xref: /xnu-8796.141.3/bsd/kern/ubc_subr.c (revision 1b191cb58250d0705d8a51287127505aa4bc0789)

/*
 * Copyright (c) 1999-2020 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
/*
 *	File:	ubc_subr.c
 *	Author:	Umesh Vaishampayan [[email protected]]
 *		05-Aug-1999	umeshv	Created.
 *
 *	Functions related to Unified Buffer cache.
 *
 * Caller of UBC functions MUST have a valid reference on the vnode.
 *
 */

#include <sys/types.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/lock.h>
#include <sys/mman.h>
#include <sys/mount_internal.h>
#include <sys/vnode_internal.h>
#include <sys/ubc_internal.h>
#include <sys/ucred.h>
#include <sys/proc_internal.h>
#include <sys/kauth.h>
#include <sys/buf.h>
#include <sys/user.h>
#include <sys/codesign.h>
#include <sys/codedir_internal.h>
#include <sys/fsevents.h>
#include <sys/fcntl.h>
#include <sys/reboot.h>
#include <sys/code_signing.h>

#include <mach/mach_types.h>
#include <mach/memory_object_types.h>
#include <mach/memory_object_control.h>
#include <mach/vm_map.h>
#include <mach/mach_vm.h>
#include <mach/upl.h>

#include <kern/kern_types.h>
#include <kern/kalloc.h>
#include <kern/zalloc.h>
#include <kern/thread.h>
#include <vm/pmap.h>
#include <vm/vm_kern.h>
#include <vm/vm_protos.h> /* last */

#include <libkern/crypto/sha1.h>
#include <libkern/crypto/sha2.h>
#include <libkern/libkern.h>

#include <security/mac_framework.h>
#include <stdbool.h>
#include <stdatomic.h>
#include <libkern/amfi/amfi.h>

/* XXX These should be in a BSD accessible Mach header, but aren't. */
extern kern_return_t memory_object_pages_resident(memory_object_control_t,
    boolean_t *);
extern kern_return_t    memory_object_signed(memory_object_control_t control,
    boolean_t is_signed);
extern boolean_t        memory_object_is_signed(memory_object_control_t);
extern void             memory_object_mark_trusted(
	memory_object_control_t         control);

extern void Debugger(const char *message);

#if DIAGNOSTIC
#if defined(assert)
#undef assert
#endif
#define assert(cond)    \
    ((void) ((cond) ? 0 : panic("Assert failed: %s", # cond)))
#else
#include <kern/assert.h>
#endif /* DIAGNOSTIC */

static int ubc_info_init_internal(struct vnode *vp, int withfsize, off_t filesize);
static int ubc_umcallback(vnode_t, void *);
static int ubc_msync_internal(vnode_t, off_t, off_t, off_t *, int, int *);
static void ubc_cs_free(struct ubc_info *uip);

static boolean_t ubc_cs_supports_multilevel_hash(struct cs_blob *blob);
static kern_return_t ubc_cs_convert_to_multilevel_hash(struct cs_blob *blob);

ZONE_DEFINE_TYPE(ubc_info_zone, "ubc_info zone", struct ubc_info,
    ZC_ZFREE_CLEARMEM);
static uint32_t cs_blob_generation_count = 1;

/*
 * CODESIGNING
 * Routines to navigate code signing data structures in the kernel...
 */

ZONE_DEFINE_ID(ZONE_ID_CS_BLOB, "cs_blob zone", struct cs_blob,
    ZC_READONLY | ZC_ZFREE_CLEARMEM);

extern int cs_debug;

#define PAGE_SHIFT_4K           (12)

static boolean_t
cs_valid_range(
	const void *start,
	const void *end,
	const void *lower_bound,
	const void *upper_bound)
{
	if (upper_bound < lower_bound ||
	    end < start) {
		return FALSE;
	}

	if (start < lower_bound ||
	    end > upper_bound) {
		return FALSE;
	}

	return TRUE;
}

typedef void (*cs_md_init)(void *ctx);
typedef void (*cs_md_update)(void *ctx, const void *data, size_t size);
typedef void (*cs_md_final)(void *hash, void *ctx);

struct cs_hash {
	uint8_t             cs_type;    /* type code as per code signing */
	size_t              cs_size;    /* size of effective hash (may be truncated) */
	size_t              cs_digest_size;/* size of native hash */
	cs_md_init          cs_init;
	cs_md_update        cs_update;
	cs_md_final         cs_final;
};

uint8_t
cs_hash_type(
	struct cs_hash const * const cs_hash)
{
	return cs_hash->cs_type;
}

static const struct cs_hash cs_hash_sha1 = {
	.cs_type = CS_HASHTYPE_SHA1,
	.cs_size = CS_SHA1_LEN,
	.cs_digest_size = SHA_DIGEST_LENGTH,
	.cs_init = (cs_md_init)SHA1Init,
	.cs_update = (cs_md_update)SHA1Update,
	.cs_final = (cs_md_final)SHA1Final,
};
#if CRYPTO_SHA2
static const struct cs_hash cs_hash_sha256 = {
	.cs_type = CS_HASHTYPE_SHA256,
	.cs_size = SHA256_DIGEST_LENGTH,
	.cs_digest_size = SHA256_DIGEST_LENGTH,
	.cs_init = (cs_md_init)SHA256_Init,
	.cs_update = (cs_md_update)SHA256_Update,
	.cs_final = (cs_md_final)SHA256_Final,
};
static const struct cs_hash cs_hash_sha256_truncate = {
	.cs_type = CS_HASHTYPE_SHA256_TRUNCATED,
	.cs_size = CS_SHA256_TRUNCATED_LEN,
	.cs_digest_size = SHA256_DIGEST_LENGTH,
	.cs_init = (cs_md_init)SHA256_Init,
	.cs_update = (cs_md_update)SHA256_Update,
	.cs_final = (cs_md_final)SHA256_Final,
};
static const struct cs_hash cs_hash_sha384 = {
	.cs_type = CS_HASHTYPE_SHA384,
	.cs_size = SHA384_DIGEST_LENGTH,
	.cs_digest_size = SHA384_DIGEST_LENGTH,
	.cs_init = (cs_md_init)SHA384_Init,
	.cs_update = (cs_md_update)SHA384_Update,
	.cs_final = (cs_md_final)SHA384_Final,
};
#endif

static struct cs_hash const *
cs_find_md(uint8_t type)
{
	if (type == CS_HASHTYPE_SHA1) {
		return &cs_hash_sha1;
#if CRYPTO_SHA2
	} else if (type == CS_HASHTYPE_SHA256) {
		return &cs_hash_sha256;
	} else if (type == CS_HASHTYPE_SHA256_TRUNCATED) {
		return &cs_hash_sha256_truncate;
	} else if (type == CS_HASHTYPE_SHA384) {
		return &cs_hash_sha384;
#endif
	}
	return NULL;
}

union cs_hash_union {
	SHA1_CTX                sha1ctxt;
	SHA256_CTX              sha256ctx;
	SHA384_CTX              sha384ctx;
};


/*
 * Choose among different hash algorithms.
 * Higher is better, 0 => don't use at all.
 */
static const uint32_t hashPriorities[] = {
	CS_HASHTYPE_SHA1,
	CS_HASHTYPE_SHA256_TRUNCATED,
	CS_HASHTYPE_SHA256,
	CS_HASHTYPE_SHA384,
};

static unsigned int
hash_rank(const CS_CodeDirectory *cd)
{
	uint32_t type = cd->hashType;
	unsigned int n;

	for (n = 0; n < sizeof(hashPriorities) / sizeof(hashPriorities[0]); ++n) {
		if (hashPriorities[n] == type) {
			return n + 1;
		}
	}
	return 0;       /* not supported */
}


/*
 * Locating a page hash
 */
static const unsigned char *
hashes(
	const CS_CodeDirectory *cd,
	uint32_t page,
	size_t hash_len,
	const char *lower_bound,
	const char *upper_bound)
{
	const unsigned char *base, *top, *hash;
	uint32_t nCodeSlots = ntohl(cd->nCodeSlots);

	assert(cs_valid_range(cd, cd + 1, lower_bound, upper_bound));

	if ((ntohl(cd->version) >= CS_SUPPORTSSCATTER) && (ntohl(cd->scatterOffset))) {
		/* Get first scatter struct */
		const SC_Scatter *scatter = (const SC_Scatter*)
		    ((const char*)cd + ntohl(cd->scatterOffset));
		uint32_t hashindex = 0, scount, sbase = 0;
		/* iterate all scatter structs */
		do {
			if ((const char*)scatter > (const char*)cd + ntohl(cd->length)) {
				if (cs_debug) {
					printf("CODE SIGNING: Scatter extends past Code Directory\n");
				}
				return NULL;
			}

			scount = ntohl(scatter->count);
			uint32_t new_base = ntohl(scatter->base);

			/* last scatter? */
			if (scount == 0) {
				return NULL;
			}

			if ((hashindex > 0) && (new_base <= sbase)) {
				if (cs_debug) {
					printf("CODE SIGNING: unordered Scatter, prev base %d, cur base %d\n",
					    sbase, new_base);
				}
				return NULL;    /* unordered scatter array */
			}
			sbase = new_base;

			/* this scatter beyond page we're looking for? */
			if (sbase > page) {
				return NULL;
			}

			if (sbase + scount >= page) {
				/* Found the scatter struct that is
				 * referencing our page */

				/* base = address of first hash covered by scatter */
				base = (const unsigned char *)cd + ntohl(cd->hashOffset) +
				    hashindex * hash_len;
				/* top = address of first hash after this scatter */
				top = base + scount * hash_len;
				if (!cs_valid_range(base, top, lower_bound,
				    upper_bound) ||
				    hashindex > nCodeSlots) {
					return NULL;
				}

				break;
			}

			/* this scatter struct is before the page we're looking
			 * for. Iterate. */
			hashindex += scount;
			scatter++;
		} while (1);

		hash = base + (page - sbase) * hash_len;
	} else {
		base = (const unsigned char *)cd + ntohl(cd->hashOffset);
		top = base + nCodeSlots * hash_len;
		if (!cs_valid_range(base, top, lower_bound, upper_bound) ||
		    page > nCodeSlots) {
			return NULL;
		}
		assert(page < nCodeSlots);

		hash = base + page * hash_len;
	}

	if (!cs_valid_range(hash, hash + hash_len,
	    lower_bound, upper_bound)) {
		hash = NULL;
	}

	return hash;
}

/*
 * cs_validate_codedirectory
 *
 * Validate that pointers inside the code directory to make sure that
 * all offsets and lengths are constrained within the buffer.
 *
 * Parameters:	cd			Pointer to code directory buffer
 *		length			Length of buffer
 *
 * Returns:	0			Success
 *		EBADEXEC		Invalid code signature
 */

static int
cs_validate_codedirectory(const CS_CodeDirectory *cd, size_t length)
{
	struct cs_hash const *hashtype;

	if (length < sizeof(*cd)) {
		return EBADEXEC;
	}
	if (ntohl(cd->magic) != CSMAGIC_CODEDIRECTORY) {
		return EBADEXEC;
	}
	if ((cd->pageSize != PAGE_SHIFT_4K) && (cd->pageSize != PAGE_SHIFT)) {
		printf("disallowing unsupported code signature page shift: %u\n", cd->pageSize);
		return EBADEXEC;
	}
	hashtype = cs_find_md(cd->hashType);
	if (hashtype == NULL) {
		return EBADEXEC;
	}

	if (cd->hashSize != hashtype->cs_size) {
		return EBADEXEC;
	}

	if (length < ntohl(cd->hashOffset)) {
		return EBADEXEC;
	}

	/* check that nSpecialSlots fits in the buffer in front of hashOffset */
	if (ntohl(cd->hashOffset) / hashtype->cs_size < ntohl(cd->nSpecialSlots)) {
		return EBADEXEC;
	}

	/* check that codeslots fits in the buffer */
	if ((length - ntohl(cd->hashOffset)) / hashtype->cs_size < ntohl(cd->nCodeSlots)) {
		return EBADEXEC;
	}

	if (ntohl(cd->version) >= CS_SUPPORTSSCATTER && cd->scatterOffset) {
		if (length < ntohl(cd->scatterOffset)) {
			return EBADEXEC;
		}

		const SC_Scatter *scatter = (const SC_Scatter *)
		    (((const uint8_t *)cd) + ntohl(cd->scatterOffset));
		uint32_t nPages = 0;

		/*
		 * Check each scatter buffer, since we don't know the
		 * length of the scatter buffer array, we have to
		 * check each entry.
		 */
		while (1) {
			/* check that the end of each scatter buffer in within the length */
			if (((const uint8_t *)scatter) + sizeof(scatter[0]) > (const uint8_t *)cd + length) {
				return EBADEXEC;
			}
			uint32_t scount = ntohl(scatter->count);
			if (scount == 0) {
				break;
			}
			if (nPages + scount < nPages) {
				return EBADEXEC;
			}
			nPages += scount;
			scatter++;

			/* XXX check that basees doesn't overlap */
			/* XXX check that targetOffset doesn't overlap */
		}
#if 0 /* rdar://12579439 */
		if (nPages != ntohl(cd->nCodeSlots)) {
			return EBADEXEC;
		}
#endif
	}

	if (length < ntohl(cd->identOffset)) {
		return EBADEXEC;
	}

	/* identifier is NUL terminated string */
	if (cd->identOffset) {
		const uint8_t *ptr = (const uint8_t *)cd + ntohl(cd->identOffset);
		if (memchr(ptr, 0, length - ntohl(cd->identOffset)) == NULL) {
			return EBADEXEC;
		}
	}

	/* team identifier is NULL terminated string */
	if (ntohl(cd->version) >= CS_SUPPORTSTEAMID && ntohl(cd->teamOffset)) {
		if (length < ntohl(cd->teamOffset)) {
			return EBADEXEC;
		}

		const uint8_t *ptr = (const uint8_t *)cd + ntohl(cd->teamOffset);
		if (memchr(ptr, 0, length - ntohl(cd->teamOffset)) == NULL) {
			return EBADEXEC;
		}
	}

	/* linkage is variable length binary data */
	if (ntohl(cd->version) >= CS_SUPPORTSLINKAGE && cd->linkageHashType != 0) {
		const uintptr_t ptr = (uintptr_t)cd + ntohl(cd->linkageOffset);
		const uintptr_t ptr_end = ptr + ntohl(cd->linkageSize);

		if (ptr_end < ptr || ptr < (uintptr_t)cd || ptr_end > (uintptr_t)cd + length) {
			return EBADEXEC;
		}
	}


	return 0;
}

/*
 *
 */

static int
cs_validate_blob(const CS_GenericBlob *blob, size_t length)
{
	if (length < sizeof(CS_GenericBlob) || length < ntohl(blob->length)) {
		return EBADEXEC;
	}
	return 0;
}

/*
 * cs_validate_csblob
 *
 * Validate that superblob/embedded code directory to make sure that
 * all internal pointers are valid.
 *
 * Will validate both a superblob csblob and a "raw" code directory.
 *
 *
 * Parameters:	buffer			Pointer to code signature
 *		length			Length of buffer
 *		rcd			returns pointer to code directory
 *
 * Returns:	0			Success
 *		EBADEXEC		Invalid code signature
 */

static int
cs_validate_csblob(
	const uint8_t *addr,
	const size_t blob_size,
	const CS_CodeDirectory **rcd,
	const CS_GenericBlob **rentitlements,
	const CS_GenericBlob **rder_entitlements)
{
	const CS_GenericBlob *blob;
	int error;
	size_t length;
	const CS_GenericBlob *self_constraint = NULL;
	const CS_GenericBlob *parent_constraint = NULL;
	const CS_GenericBlob *responsible_proc_constraint = NULL;

	*rcd = NULL;
	*rentitlements = NULL;
	*rder_entitlements = NULL;

	blob = (const CS_GenericBlob *)(const void *)addr;

	length = blob_size;
	error = cs_validate_blob(blob, length);
	if (error) {
		return error;
	}
	length = ntohl(blob->length);

	if (ntohl(blob->magic) == CSMAGIC_EMBEDDED_SIGNATURE) {
		const CS_SuperBlob *sb;
		uint32_t n, count;
		const CS_CodeDirectory *best_cd = NULL;
		unsigned int best_rank = 0;
#if XNU_PLATFORM_WatchOS
		const CS_CodeDirectory *sha1_cd = NULL;
#endif

		if (length < sizeof(CS_SuperBlob)) {
			return EBADEXEC;
		}

		sb = (const CS_SuperBlob *)blob;
		count = ntohl(sb->count);

		/* check that the array of BlobIndex fits in the rest of the data */
		if ((length - sizeof(CS_SuperBlob)) / sizeof(CS_BlobIndex) < count) {
			return EBADEXEC;
		}

		/* now check each BlobIndex */
		for (n = 0; n < count; n++) {
			const CS_BlobIndex *blobIndex = &sb->index[n];
			uint32_t type = ntohl(blobIndex->type);
			uint32_t offset = ntohl(blobIndex->offset);
			if (length < offset) {
				return EBADEXEC;
			}

			const CS_GenericBlob *subBlob =
			    (const CS_GenericBlob *)(const void *)(addr + offset);

			size_t subLength = length - offset;

			if ((error = cs_validate_blob(subBlob, subLength)) != 0) {
				return error;
			}
			subLength = ntohl(subBlob->length);

			/* extra validation for CDs, that is also returned */
			if (type == CSSLOT_CODEDIRECTORY || (type >= CSSLOT_ALTERNATE_CODEDIRECTORIES && type < CSSLOT_ALTERNATE_CODEDIRECTORY_LIMIT)) {
				const CS_CodeDirectory *candidate = (const CS_CodeDirectory *)subBlob;
				if ((error = cs_validate_codedirectory(candidate, subLength)) != 0) {
					return error;
				}
				unsigned int rank = hash_rank(candidate);
				if (cs_debug > 3) {
					printf("CodeDirectory type %d rank %d at slot 0x%x index %d\n", candidate->hashType, (int)rank, (int)type, (int)n);
				}
				if (best_cd == NULL || rank > best_rank) {
					best_cd = candidate;
					best_rank = rank;

					if (cs_debug > 2) {
						printf("using CodeDirectory type %d (rank %d)\n", (int)best_cd->hashType, best_rank);
					}
					*rcd = best_cd;
				} else if (best_cd != NULL && rank == best_rank) {
					/* repeat of a hash type (1:1 mapped to ranks), illegal and suspicious */
					printf("multiple hash=%d CodeDirectories in signature; rejecting\n", best_cd->hashType);
					return EBADEXEC;
				}
#if XNU_PLATFORM_WatchOS
				if (candidate->hashType == CS_HASHTYPE_SHA1) {
					if (sha1_cd != NULL) {
						printf("multiple sha1 CodeDirectories in signature; rejecting\n");
						return EBADEXEC;
					}
					sha1_cd = candidate;
				}
#endif
			} else if (type == CSSLOT_ENTITLEMENTS) {
				if (ntohl(subBlob->magic) != CSMAGIC_EMBEDDED_ENTITLEMENTS) {
					return EBADEXEC;
				}
				if (*rentitlements != NULL) {
					printf("multiple entitlements blobs\n");
					return EBADEXEC;
				}
				*rentitlements = subBlob;
			} else if (type == CSSLOT_DER_ENTITLEMENTS) {
				if (ntohl(subBlob->magic) != CSMAGIC_EMBEDDED_DER_ENTITLEMENTS) {
					return EBADEXEC;
				}
				if (*rder_entitlements != NULL) {
					printf("multiple der entitlements blobs\n");
					return EBADEXEC;
				}
				*rder_entitlements = subBlob;
			} else if (type == CSSLOT_LAUNCH_CONSTRAINT_SELF) {
				if (ntohl(subBlob->magic) != CSMAGIC_EMBEDDED_LAUNCH_CONSTRAINT) {
					return EBADEXEC;
				}
				if (self_constraint != NULL) {
					printf("multiple self constraint blobs\n");
					return EBADEXEC;
				}
				self_constraint = subBlob;
			} else if (type == CSSLOT_LAUNCH_CONSTRAINT_PARENT) {
				if (ntohl(subBlob->magic) != CSMAGIC_EMBEDDED_LAUNCH_CONSTRAINT) {
					return EBADEXEC;
				}
				if (parent_constraint != NULL) {
					printf("multiple parent constraint blobs\n");
					return EBADEXEC;
				}
				parent_constraint = subBlob;
			} else if (type == CSSLOT_LAUNCH_CONSTRAINT_RESPONSIBLE) {
				if (ntohl(subBlob->magic) != CSMAGIC_EMBEDDED_LAUNCH_CONSTRAINT) {
					return EBADEXEC;
				}
				if (responsible_proc_constraint != NULL) {
					printf("multiple responsible process constraint blobs\n");
					return EBADEXEC;
				}
				responsible_proc_constraint = subBlob;
			}
		}

#if XNU_PLATFORM_WatchOS
		/* To keep watchOS fast enough, we have to resort to sha1 for
		 * some code.
		 *
		 * At the time of writing this comment, known sha1 attacks are
		 * collision attacks (not preimage or second preimage
		 * attacks), which do not apply to platform binaries since
		 * they have a fixed hash in the trust cache.  Given this
		 * property, we only prefer sha1 code directories for adhoc
		 * signatures, which always have to be in a trust cache to be
		 * valid (can-load-cdhash does not exist for watchOS). Those
		 * are, incidentally, also the platform binaries, for which we
		 * care about the performance hit that sha256 would bring us.
		 *
		 * Platform binaries may still contain a (not chosen) sha256
		 * code directory, which keeps software updates that switch to
		 * sha256-only small.
		 */

		if (*rcd != NULL && sha1_cd != NULL && (ntohl(sha1_cd->flags) & CS_ADHOC)) {
			if (sha1_cd->flags != (*rcd)->flags) {
				printf("mismatched flags between hash %d (flags: %#x) and sha1 (flags: %#x) cd.\n",
				    (int)(*rcd)->hashType, (*rcd)->flags, sha1_cd->flags);
				*rcd = NULL;
				return EBADEXEC;
			}

			*rcd = sha1_cd;
		}
#endif
	} else if (ntohl(blob->magic) == CSMAGIC_CODEDIRECTORY) {
		if ((error = cs_validate_codedirectory((const CS_CodeDirectory *)(const void *)addr, length)) != 0) {
			return error;
		}
		*rcd = (const CS_CodeDirectory *)blob;
	} else {
		return EBADEXEC;
	}

	if (*rcd == NULL) {
		return EBADEXEC;
	}

	return 0;
}

/*
 * cs_find_blob_bytes
 *
 * Find an blob from the superblob/code directory. The blob must have
 * been been validated by cs_validate_csblob() before calling
 * this. Use csblob_find_blob() instead.
 *
 * Will also find a "raw" code directory if its stored as well as
 * searching the superblob.
 *
 * Parameters:	buffer			Pointer to code signature
 *		length			Length of buffer
 *		type			type of blob to find
 *		magic			the magic number for that blob
 *
 * Returns:	pointer			Success
 *		NULL			Buffer not found
 */

const CS_GenericBlob *
csblob_find_blob_bytes(const uint8_t *addr, size_t length, uint32_t type, uint32_t magic)
{
	const CS_GenericBlob *blob = (const CS_GenericBlob *)(const void *)addr;

	if ((addr + length) < addr) {
		panic("CODE SIGNING: CS Blob length overflow for addr: %p", addr);
	}

	if (ntohl(blob->magic) == CSMAGIC_EMBEDDED_SIGNATURE) {
		const CS_SuperBlob *sb = (const CS_SuperBlob *)blob;
		size_t n, count = ntohl(sb->count);

		for (n = 0; n < count; n++) {
			if (ntohl(sb->index[n].type) != type) {
				continue;
			}
			uint32_t offset = ntohl(sb->index[n].offset);
			if (length - sizeof(const CS_GenericBlob) < offset) {
				return NULL;
			}
			blob = (const CS_GenericBlob *)(const void *)(addr + offset);
			if (ntohl(blob->magic) != magic) {
				continue;
			}
			if (((vm_address_t)blob + ntohl(blob->length)) < (vm_address_t)blob) {
				panic("CODE SIGNING: CS Blob length overflow for blob at: %p", blob);
			} else if (((vm_address_t)blob + ntohl(blob->length)) > (vm_address_t)(addr + length)) {
				continue;
			}
			return blob;
		}
	} else if (type == CSSLOT_CODEDIRECTORY && ntohl(blob->magic) == CSMAGIC_CODEDIRECTORY
	    && magic == CSMAGIC_CODEDIRECTORY) {
		if (((vm_address_t)blob + ntohl(blob->length)) < (vm_address_t)blob) {
			panic("CODE SIGNING: CS Blob length overflow for code directory blob at: %p", blob);
		} else if (((vm_address_t)blob + ntohl(blob->length)) > (vm_address_t)(addr + length)) {
			return NULL;
		}
		return blob;
	}
	return NULL;
}


const CS_GenericBlob *
csblob_find_blob(struct cs_blob *csblob, uint32_t type, uint32_t magic)
{
	if ((csblob->csb_flags & CS_VALID) == 0) {
		return NULL;
	}
	return csblob_find_blob_bytes((const uint8_t *)csblob->csb_mem_kaddr, csblob->csb_mem_size, type, magic);
}

static const uint8_t *
find_special_slot(const CS_CodeDirectory *cd, size_t slotsize, uint32_t slot)
{
	/* there is no zero special slot since that is the first code slot */
	if (ntohl(cd->nSpecialSlots) < slot || slot == 0) {
		return NULL;
	}

	return (const uint8_t *)cd + ntohl(cd->hashOffset) - (slotsize * slot);
}

static uint8_t cshash_zero[CS_HASH_MAX_SIZE] = { 0 };

static int
csblob_find_special_slot_blob(struct cs_blob* csblob, uint32_t slot, uint32_t magic, const CS_GenericBlob **out_start, size_t *out_length)
{
	uint8_t computed_hash[CS_HASH_MAX_SIZE];
	const CS_GenericBlob *blob;
	const CS_CodeDirectory *code_dir;
	const uint8_t *embedded_hash;
	union cs_hash_union context;

	if (out_start) {
		*out_start = NULL;
	}
	if (out_length) {
		*out_length = 0;
	}

	if (csblob->csb_hashtype == NULL || csblob->csb_hashtype->cs_digest_size > sizeof(computed_hash)) {
		return EBADEXEC;
	}

	code_dir = csblob->csb_cd;

	blob = csblob_find_blob_bytes((const uint8_t *)csblob->csb_mem_kaddr, csblob->csb_mem_size, slot, magic);

	embedded_hash = find_special_slot(code_dir, csblob->csb_hashtype->cs_size, slot);

	if (embedded_hash == NULL) {
		if (blob) {
			return EBADEXEC;
		}
		return 0;
	} else if (blob == NULL) {
		if (memcmp(embedded_hash, cshash_zero, csblob->csb_hashtype->cs_size) != 0) {
			return EBADEXEC;
		} else {
			return 0;
		}
	}

	csblob->csb_hashtype->cs_init(&context);
	csblob->csb_hashtype->cs_update(&context, blob, ntohl(blob->length));
	csblob->csb_hashtype->cs_final(computed_hash, &context);

	if (memcmp(computed_hash, embedded_hash, csblob->csb_hashtype->cs_size) != 0) {
		return EBADEXEC;
	}
	if (out_start) {
		*out_start = blob;
	}
	if (out_length) {
		*out_length = ntohl(blob->length);
	}

	return 0;
}

int
csblob_get_entitlements(struct cs_blob *csblob, void **out_start, size_t *out_length)
{
	uint8_t computed_hash[CS_HASH_MAX_SIZE];
	const CS_GenericBlob *entitlements;
	const CS_CodeDirectory *code_dir;
	const uint8_t *embedded_hash;
	union cs_hash_union context;

	*out_start = NULL;
	*out_length = 0;

	if (csblob->csb_hashtype == NULL || csblob->csb_hashtype->cs_digest_size > sizeof(computed_hash)) {
		return EBADEXEC;
	}

	code_dir = csblob->csb_cd;

	if ((csblob->csb_flags & CS_VALID) == 0) {
		entitlements = NULL;
	} else {
		entitlements = csblob->csb_entitlements_blob;
	}
	embedded_hash = find_special_slot(code_dir, csblob->csb_hashtype->cs_size, CSSLOT_ENTITLEMENTS);

	if (embedded_hash == NULL) {
		if (entitlements) {
			return EBADEXEC;
		}
		return 0;
	} else if (entitlements == NULL) {
		if (memcmp(embedded_hash, cshash_zero, csblob->csb_hashtype->cs_size) != 0) {
			return EBADEXEC;
		} else {
			return 0;
		}
	}

	csblob->csb_hashtype->cs_init(&context);
	csblob->csb_hashtype->cs_update(&context, entitlements, ntohl(entitlements->length));
	csblob->csb_hashtype->cs_final(computed_hash, &context);

	if (memcmp(computed_hash, embedded_hash, csblob->csb_hashtype->cs_size) != 0) {
		return EBADEXEC;
	}

	*out_start = __DECONST(void *, entitlements);
	*out_length = ntohl(entitlements->length);

	return 0;
}

const CS_GenericBlob*
csblob_get_der_entitlements_unsafe(struct cs_blob * csblob)
{
	if ((csblob->csb_flags & CS_VALID) == 0) {
		return NULL;
	}

	return csblob->csb_der_entitlements_blob;
}

int
csblob_get_der_entitlements(struct cs_blob *csblob, const CS_GenericBlob **out_start, size_t *out_length)
{
	uint8_t computed_hash[CS_HASH_MAX_SIZE];
	const CS_GenericBlob *der_entitlements;
	const CS_CodeDirectory *code_dir;
	const uint8_t *embedded_hash;
	union cs_hash_union context;

	*out_start = NULL;
	*out_length = 0;

	if (csblob->csb_hashtype == NULL || csblob->csb_hashtype->cs_digest_size > sizeof(computed_hash)) {
		return EBADEXEC;
	}

	code_dir = csblob->csb_cd;

	if ((csblob->csb_flags & CS_VALID) == 0) {
		der_entitlements = NULL;
	} else {
		der_entitlements = csblob->csb_der_entitlements_blob;
	}
	embedded_hash = find_special_slot(code_dir, csblob->csb_hashtype->cs_size, CSSLOT_DER_ENTITLEMENTS);

	if (embedded_hash == NULL) {
		if (der_entitlements) {
			return EBADEXEC;
		}
		return 0;
	} else if (der_entitlements == NULL) {
		if (memcmp(embedded_hash, cshash_zero, csblob->csb_hashtype->cs_size) != 0) {
			return EBADEXEC;
		} else {
			return 0;
		}
	}

	csblob->csb_hashtype->cs_init(&context);
	csblob->csb_hashtype->cs_update(&context, der_entitlements, ntohl(der_entitlements->length));
	csblob->csb_hashtype->cs_final(computed_hash, &context);

	if (memcmp(computed_hash, embedded_hash, csblob->csb_hashtype->cs_size) != 0) {
		return EBADEXEC;
	}

	*out_start = der_entitlements;
	*out_length = ntohl(der_entitlements->length);

	return 0;
}

static bool
ubc_cs_blob_pagewise_allocate(
	__unused vm_size_t size)
{
#if CODE_SIGNING_MONITOR
	/* If the monitor isn't enabled, then we don't need to page-align */
	if (csm_enabled() == false) {
		return false;
	}

	/*
	 * Small allocations can be maanged by the monitor itself. We only need to allocate
	 * page-wise when it is a sufficiently large allocation and the monitor cannot manage
	 * it on its own.
	 */
	if (size <= csm_signature_size_limit()) {
		return false;
	}

	return true;
#else
	/* Without a monitor, we never need to page align */
	return false;
#endif /* CODE_SIGNING_MONITOR */
}

int
csblob_register_profile_uuid(
	struct cs_blob __unused *csblob,
	const uuid_t __unused profile_uuid,
	void __unused *profile_addr,
	vm_size_t __unused profile_size)
{
#if CODE_SIGNING_MONITOR
	/* Profiles only need to be registered for monitor environments */
	assert(profile_addr != NULL);
	assert(profile_size != 0);
	assert(csblob != NULL);

	kern_return_t kr = csm_register_provisioning_profile(
		profile_uuid,
		profile_addr, profile_size);

	if ((kr != KERN_SUCCESS) && (kr != KERN_ALREADY_IN_SET)) {
		return EPERM;
	}

	/* Associate the profile with the monitor's signature object */
	kr = csm_associate_provisioning_profile(
		csblob->csb_csm_obj,
		profile_uuid);

	if ((kr != KERN_SUCCESS) && (kr != KERN_NOT_SUPPORTED)) {
		return EPERM;
	}

	return 0;
#else
	return 0;
#endif /* CODE_SIGNING_MONITOR */
}

/*
 * CODESIGNING
 * End of routines to navigate code signing data structures in the kernel.
 */



/*
 * ubc_info_init
 *
 * Allocate and attach an empty ubc_info structure to a vnode
 *
 * Parameters:	vp			Pointer to the vnode
 *
 * Returns:	0			Success
 *	vnode_size:ENOMEM		Not enough space
 *	vnode_size:???			Other error from vnode_getattr
 *
 */
int
ubc_info_init(struct vnode *vp)
{
	return ubc_info_init_internal(vp, 0, 0);
}


/*
 * ubc_info_init_withsize
 *
 * Allocate and attach a sized ubc_info structure to a vnode
 *
 * Parameters:	vp			Pointer to the vnode
 *		filesize		The size of the file
 *
 * Returns:	0			Success
 *	vnode_size:ENOMEM		Not enough space
 *	vnode_size:???			Other error from vnode_getattr
 */
int
ubc_info_init_withsize(struct vnode *vp, off_t filesize)
{
	return ubc_info_init_internal(vp, 1, filesize);
}


/*
 * ubc_info_init_internal
 *
 * Allocate and attach a ubc_info structure to a vnode
 *
 * Parameters:	vp			Pointer to the vnode
 *		withfsize{0,1}		Zero if the size should be obtained
 *					from the vnode; otherwise, use filesize
 *		filesize		The size of the file, if withfsize == 1
 *
 * Returns:	0			Success
 *	vnode_size:ENOMEM		Not enough space
 *	vnode_size:???			Other error from vnode_getattr
 *
 * Notes:	We call a blocking zalloc(), and the zone was created as an
 *		expandable and collectable zone, so if no memory is available,
 *		it is possible for zalloc() to block indefinitely.  zalloc()
 *		may also panic if the zone of zones is exhausted, since it's
 *		NOT expandable.
 *
 *		We unconditionally call vnode_pager_setup(), even if this is
 *		a reuse of a ubc_info; in that case, we should probably assert
 *		that it does not already have a pager association, but do not.
 *
 *		Since memory_object_create_named() can only fail from receiving
 *		an invalid pager argument, the explicit check and panic is
 *		merely precautionary.
 */
static int
ubc_info_init_internal(vnode_t vp, int withfsize, off_t filesize)
{
	struct ubc_info *uip;
	void *  pager;
	int error = 0;
	kern_return_t kret;
	memory_object_control_t control;

	uip = vp->v_ubcinfo;

	/*
	 * If there is not already a ubc_info attached to the vnode, we
	 * attach one; otherwise, we will reuse the one that's there.
	 */
	if (uip == UBC_INFO_NULL) {
		uip = zalloc_flags(ubc_info_zone, Z_WAITOK | Z_ZERO);

		uip->ui_vnode = vp;
		uip->ui_flags = UI_INITED;
		uip->ui_ucred = NOCRED;
	}
	assert(uip->ui_flags != UI_NONE);
	assert(uip->ui_vnode == vp);

	/* now set this ubc_info in the vnode */
	vp->v_ubcinfo = uip;

	/*
	 * Allocate a pager object for this vnode
	 *
	 * XXX The value of the pager parameter is currently ignored.
	 * XXX Presumably, this API changed to avoid the race between
	 * XXX setting the pager and the UI_HASPAGER flag.
	 */
	pager = (void *)vnode_pager_setup(vp, uip->ui_pager);
	assert(pager);

	/*
	 * Explicitly set the pager into the ubc_info, after setting the
	 * UI_HASPAGER flag.
	 */
	SET(uip->ui_flags, UI_HASPAGER);
	uip->ui_pager = pager;

	/*
	 * Note: We can not use VNOP_GETATTR() to get accurate
	 * value of ui_size because this may be an NFS vnode, and
	 * nfs_getattr() can call vinvalbuf(); if this happens,
	 * ubc_info is not set up to deal with that event.
	 * So use bogus size.
	 */

	/*
	 * create a vnode - vm_object association
	 * memory_object_create_named() creates a "named" reference on the
	 * memory object we hold this reference as long as the vnode is
	 * "alive."  Since memory_object_create_named() took its own reference
	 * on the vnode pager we passed it, we can drop the reference
	 * vnode_pager_setup() returned here.
	 */
	kret = memory_object_create_named(pager,
	    (memory_object_size_t)uip->ui_size, &control);
	vnode_pager_deallocate(pager);
	if (kret != KERN_SUCCESS) {
		panic("ubc_info_init: memory_object_create_named returned %d", kret);
	}

	assert(control);
	uip->ui_control = control;      /* cache the value of the mo control */
	SET(uip->ui_flags, UI_HASOBJREF);       /* with a named reference */

	if (withfsize == 0) {
		/* initialize the size */
		error = vnode_size(vp, &uip->ui_size, vfs_context_current());
		if (error) {
			uip->ui_size = 0;
		}
	} else {
		uip->ui_size = filesize;
	}
	vp->v_lflag |= VNAMED_UBC;      /* vnode has a named ubc reference */

	return error;
}


/*
 * ubc_info_free
 *
 * Free a ubc_info structure
 *
 * Parameters:	uip			A pointer to the ubc_info to free
 *
 * Returns:	(void)
 *
 * Notes:	If there is a credential that has subsequently been associated
 *		with the ubc_info, the reference to the credential is dropped.
 *
 *		It's actually impossible for a ubc_info.ui_control to take the
 *		value MEMORY_OBJECT_CONTROL_NULL.
 */
static void
ubc_info_free(struct ubc_info *uip)
{
	if (IS_VALID_CRED(uip->ui_ucred)) {
		kauth_cred_unref(&uip->ui_ucred);
	}

	if (uip->ui_control != MEMORY_OBJECT_CONTROL_NULL) {
		memory_object_control_deallocate(uip->ui_control);
	}

	cluster_release(uip);
	ubc_cs_free(uip);

	zfree(ubc_info_zone, uip);
	return;
}


void
ubc_info_deallocate(struct ubc_info *uip)
{
	ubc_info_free(uip);
}

/*
 * ubc_setsize_ex
 *
 * Tell the VM that the the size of the file represented by the vnode has
 * changed
 *
 * Parameters:	vp	   The vp whose backing file size is
 *					   being changed
 *				nsize  The new size of the backing file
 *				opts   Options
 *
 * Returns:	EINVAL for new size < 0
 *			ENOENT if no UBC info exists
 *          EAGAIN if UBC_SETSIZE_NO_FS_REENTRY option is set and new_size < old size
 *          Other errors (mapped to errno_t) returned by VM functions
 *
 * Notes:   This function will indicate success if the new size is the
 *		    same or larger than the old size (in this case, the
 *		    remainder of the file will require modification or use of
 *		    an existing upl to access successfully).
 *
 *		    This function will fail if the new file size is smaller,
 *		    and the memory region being invalidated was unable to
 *		    actually be invalidated and/or the last page could not be
 *		    flushed, if the new size is not aligned to a page
 *		    boundary.  This is usually indicative of an I/O error.
 */
errno_t
ubc_setsize_ex(struct vnode *vp, off_t nsize, ubc_setsize_opts_t opts)
{
	off_t osize;    /* ui_size before change */
	off_t lastpg, olastpgend, lastoff;
	struct ubc_info *uip;
	memory_object_control_t control;
	kern_return_t kret = KERN_SUCCESS;

	if (nsize < (off_t)0) {
		return EINVAL;
	}

	if (!UBCINFOEXISTS(vp)) {
		return ENOENT;
	}

	uip = vp->v_ubcinfo;
	osize = uip->ui_size;

	if (ISSET(opts, UBC_SETSIZE_NO_FS_REENTRY) && nsize < osize) {
		return EAGAIN;
	}

	/*
	 * Update the size before flushing the VM
	 */
	uip->ui_size = nsize;

	if (nsize >= osize) {   /* Nothing more to do */
		if (nsize > osize) {
			lock_vnode_and_post(vp, NOTE_EXTEND);
		}

		return 0;
	}

	/*
	 * When the file shrinks, invalidate the pages beyond the
	 * new size. Also get rid of garbage beyond nsize on the
	 * last page. The ui_size already has the nsize, so any
	 * subsequent page-in will zero-fill the tail properly
	 */
	lastpg = trunc_page_64(nsize);
	olastpgend = round_page_64(osize);
	control = uip->ui_control;
	assert(control);
	lastoff = (nsize & PAGE_MASK_64);

	if (lastoff) {
		upl_t           upl;
		upl_page_info_t *pl;

		/*
		 * new EOF ends up in the middle of a page
		 * zero the tail of this page if it's currently
		 * present in the cache
		 */
		kret = ubc_create_upl_kernel(vp, lastpg, PAGE_SIZE, &upl, &pl, UPL_SET_LITE | UPL_WILL_MODIFY, VM_KERN_MEMORY_FILE);

		if (kret != KERN_SUCCESS) {
			panic("ubc_setsize: ubc_create_upl (error = %d)", kret);
		}

		if (upl_valid_page(pl, 0)) {
			cluster_zero(upl, (uint32_t)lastoff, PAGE_SIZE - (uint32_t)lastoff, NULL);
		}

		ubc_upl_abort_range(upl, 0, PAGE_SIZE, UPL_ABORT_FREE_ON_EMPTY);

		lastpg += PAGE_SIZE_64;
	}
	if (olastpgend > lastpg) {
		int     flags;

		if (lastpg == 0) {
			flags = MEMORY_OBJECT_DATA_FLUSH_ALL;
		} else {
			flags = MEMORY_OBJECT_DATA_FLUSH;
		}
		/*
		 * invalidate the pages beyond the new EOF page
		 *
		 */
		kret = memory_object_lock_request(control,
		    (memory_object_offset_t)lastpg,
		    (memory_object_size_t)(olastpgend - lastpg), NULL, NULL,
		    MEMORY_OBJECT_RETURN_NONE, flags, VM_PROT_NO_CHANGE);
		if (kret != KERN_SUCCESS) {
			printf("ubc_setsize: invalidate failed (error = %d)\n", kret);
		}
	}
	return mach_to_bsd_errno(kret);
}

// Returns true for success
int
ubc_setsize(vnode_t vp, off_t nsize)
{
	return ubc_setsize_ex(vp, nsize, 0) == 0;
}

/*
 * ubc_getsize
 *
 * Get the size of the file assocated with the specified vnode
 *
 * Parameters:	vp			The vnode whose size is of interest
 *
 * Returns:	0			There is no ubc_info associated with
 *					this vnode, or the size is zero
 *		!0			The size of the file
 *
 * Notes:	Using this routine, it is not possible for a caller to
 *		successfully distinguish between a vnode associate with a zero
 *		length file, and a vnode with no associated ubc_info.  The
 *		caller therefore needs to not care, or needs to ensure that
 *		they have previously successfully called ubc_info_init() or
 *		ubc_info_init_withsize().
 */
off_t
ubc_getsize(struct vnode *vp)
{
	/* people depend on the side effect of this working this way
	 * as they call this for directory
	 */
	if (!UBCINFOEXISTS(vp)) {
		return (off_t)0;
	}
	return vp->v_ubcinfo->ui_size;
}


/*
 * ubc_umount
 *
 * Call ubc_msync(vp, 0, EOF, NULL, UBC_PUSHALL) on all the vnodes for this
 * mount point
 *
 * Parameters:	mp			The mount point
 *
 * Returns:	0			Success
 *
 * Notes:	There is no failure indication for this function.
 *
 *		This function is used in the unmount path; since it may block
 *		I/O indefinitely, it should not be used in the forced unmount
 *		path, since a device unavailability could also block that
 *		indefinitely.
 *
 *		Because there is no device ejection interlock on USB, FireWire,
 *		or similar devices, it's possible that an ejection that begins
 *		subsequent to the vnode_iterate() completing, either on one of
 *		those devices, or a network mount for which the server quits
 *		responding, etc., may cause the caller to block indefinitely.
 */
__private_extern__ int
ubc_umount(struct mount *mp)
{
	vnode_iterate(mp, 0, ubc_umcallback, 0);
	return 0;
}


/*
 * ubc_umcallback
 *
 * Used by ubc_umount() as an internal implementation detail; see ubc_umount()
 * and vnode_iterate() for details of implementation.
 */
static int
ubc_umcallback(vnode_t vp, __unused void * args)
{
	if (UBCINFOEXISTS(vp)) {
		(void) ubc_msync(vp, (off_t)0, ubc_getsize(vp), NULL, UBC_PUSHALL);
	}
	return VNODE_RETURNED;
}


/*
 * ubc_getcred
 *
 * Get the credentials currently active for the ubc_info associated with the
 * vnode.
 *
 * Parameters:	vp			The vnode whose ubc_info credentials
 *					are to be retrieved
 *
 * Returns:	!NOCRED			The credentials
 *		NOCRED			If there is no ubc_info for the vnode,
 *					or if there is one, but it has not had
 *					any credentials associated with it.
 */
kauth_cred_t
ubc_getcred(struct vnode *vp)
{
	if (UBCINFOEXISTS(vp)) {
		return vp->v_ubcinfo->ui_ucred;
	}

	return NOCRED;
}


/*
 * ubc_setthreadcred
 *
 * If they are not already set, set the credentials of the ubc_info structure
 * associated with the vnode to those of the supplied thread; otherwise leave
 * them alone.
 *
 * Parameters:	vp			The vnode whose ubc_info creds are to
 *					be set
 *		p			The process whose credentials are to
 *					be used, if not running on an assumed
 *					credential
 *		thread			The thread whose credentials are to
 *					be used
 *
 * Returns:	1			This vnode has no associated ubc_info
 *		0			Success
 *
 * Notes:	This function is generally used only in the following cases:
 *
 *		o	a memory mapped file via the mmap() system call
 *		o	a swap store backing file
 *		o	subsequent to a successful write via vn_write()
 *
 *		The information is then used by the NFS client in order to
 *		cons up a wire message in either the page-in or page-out path.
 *
 *		There are two potential problems with the use of this API:
 *
 *		o	Because the write path only set it on a successful
 *			write, there is a race window between setting the
 *			credential and its use to evict the pages to the
 *			remote file server
 *
 *		o	Because a page-in may occur prior to a write, the
 *			credential may not be set at this time, if the page-in
 *			is not the result of a mapping established via mmap().
 *
 *		In both these cases, this will be triggered from the paging
 *		path, which will instead use the credential of the current
 *		process, which in this case is either the dynamic_pager or
 *		the kernel task, both of which utilize "root" credentials.
 *
 *		This may potentially permit operations to occur which should
 *		be denied, or it may cause to be denied operations which
 *		should be permitted, depending on the configuration of the NFS
 *		server.
 */
int
ubc_setthreadcred(struct vnode *vp, proc_t p, thread_t thread)
{
#pragma unused(p, thread)
	assert(p == current_proc());
	assert(thread == current_thread());

	return ubc_setcred(vp, kauth_cred_get());
}


/*
 * ubc_setcred
 *
 * If they are not already set, set the credentials of the ubc_info structure
 * associated with the vnode to those specified; otherwise leave them
 * alone.
 *
 * Parameters:	vp			The vnode whose ubc_info creds are to
 *					be set
 *		ucred			The credentials to use
 *
 * Returns:	0			This vnode has no associated ubc_info
 *		1			Success
 *
 * Notes:	The return values for this function are inverted from nearly
 *		all other uses in the kernel.
 *
 *		See also ubc_setthreadcred(), above.
 */
int
ubc_setcred(struct vnode *vp, kauth_cred_t ucred)
{
	struct ubc_info *uip;

	/* If there is no ubc_info, deny the operation */
	if (!UBCINFOEXISTS(vp)) {
		return 0;
	}

	/*
	 * Check to see if there is already a credential reference in the
	 * ubc_info; if there is not, take one on the supplied credential.
	 */
	vnode_lock(vp);
	uip = vp->v_ubcinfo;
	if (!IS_VALID_CRED(uip->ui_ucred)) {
		kauth_cred_ref(ucred);
		uip->ui_ucred = ucred;
	}
	vnode_unlock(vp);

	return 1;
}

/*
 * ubc_getpager
 *
 * Get the pager associated with the ubc_info associated with the vnode.
 *
 * Parameters:	vp			The vnode to obtain the pager from
 *
 * Returns:	!VNODE_PAGER_NULL	The memory_object_t for the pager
 *		VNODE_PAGER_NULL	There is no ubc_info for this vnode
 *
 * Notes:	For each vnode that has a ubc_info associated with it, that
 *		ubc_info SHALL have a pager associated with it, so in the
 *		normal case, it's impossible to return VNODE_PAGER_NULL for
 *		a vnode with an associated ubc_info.
 */
__private_extern__ memory_object_t
ubc_getpager(struct vnode *vp)
{
	if (UBCINFOEXISTS(vp)) {
		return vp->v_ubcinfo->ui_pager;
	}

	return 0;
}


/*
 * ubc_getobject
 *
 * Get the memory object control associated with the ubc_info associated with
 * the vnode
 *
 * Parameters:	vp			The vnode to obtain the memory object
 *					from
 *		flags			DEPRECATED
 *
 * Returns:	!MEMORY_OBJECT_CONTROL_NULL
 *		MEMORY_OBJECT_CONTROL_NULL
 *
 * Notes:	Historically, if the flags were not "do not reactivate", this
 *		function would look up the memory object using the pager if
 *		it did not exist (this could be the case if the vnode had
 *		been previously reactivated).  The flags would also permit a
 *		hold to be requested, which would have created an object
 *		reference, if one had not already existed.  This usage is
 *		deprecated, as it would permit a race between finding and
 *		taking the reference vs. a single reference being dropped in
 *		another thread.
 */
memory_object_control_t
ubc_getobject(struct vnode *vp, __unused int flags)
{
	if (UBCINFOEXISTS(vp)) {
		return vp->v_ubcinfo->ui_control;
	}

	return MEMORY_OBJECT_CONTROL_NULL;
}

/*
 * ubc_blktooff
 *
 * Convert a given block number to a memory backing object (file) offset for a
 * given vnode
 *
 * Parameters:	vp			The vnode in which the block is located
 *		blkno			The block number to convert
 *
 * Returns:	!-1			The offset into the backing object
 *		-1			There is no ubc_info associated with
 *					the vnode
 *		-1			An error occurred in the underlying VFS
 *					while translating the block to an
 *					offset; the most likely cause is that
 *					the caller specified a block past the
 *					end of the file, but this could also be
 *					any other error from VNOP_BLKTOOFF().
 *
 * Note:	Representing the error in band loses some information, but does
 *		not occlude a valid offset, since an off_t of -1 is normally
 *		used to represent EOF.  If we had a more reliable constant in
 *		our header files for it (i.e. explicitly cast to an off_t), we
 *		would use it here instead.
 */
off_t
ubc_blktooff(vnode_t vp, daddr64_t blkno)
{
	off_t file_offset = -1;
	int error;

	if (UBCINFOEXISTS(vp)) {
		error = VNOP_BLKTOOFF(vp, blkno, &file_offset);
		if (error) {
			file_offset = -1;
		}
	}

	return file_offset;
}


/*
 * ubc_offtoblk
 *
 * Convert a given offset in a memory backing object into a block number for a
 * given vnode
 *
 * Parameters:	vp			The vnode in which the offset is
 *					located
 *		offset			The offset into the backing object
 *
 * Returns:	!-1			The returned block number
 *		-1			There is no ubc_info associated with
 *					the vnode
 *		-1			An error occurred in the underlying VFS
 *					while translating the block to an
 *					offset; the most likely cause is that
 *					the caller specified a block past the
 *					end of the file, but this could also be
 *					any other error from VNOP_OFFTOBLK().
 *
 * Note:	Representing the error in band loses some information, but does
 *		not occlude a valid block number, since block numbers exceed
 *		the valid range for offsets, due to their relative sizes.  If
 *		we had a more reliable constant than -1 in our header files
 *		for it (i.e. explicitly cast to an daddr64_t), we would use it
 *		here instead.
 */
daddr64_t
ubc_offtoblk(vnode_t vp, off_t offset)
{
	daddr64_t blkno = -1;
	int error = 0;

	if (UBCINFOEXISTS(vp)) {
		error = VNOP_OFFTOBLK(vp, offset, &blkno);
		if (error) {
			blkno = -1;
		}
	}

	return blkno;
}


/*
 * ubc_pages_resident
 *
 * Determine whether or not a given vnode has pages resident via the memory
 * object control associated with the ubc_info associated with the vnode
 *
 * Parameters:	vp			The vnode we want to know about
 *
 * Returns:	1			Yes
 *		0			No
 */
int
ubc_pages_resident(vnode_t vp)
{
	kern_return_t           kret;
	boolean_t                       has_pages_resident;

	if (!UBCINFOEXISTS(vp)) {
		return 0;
	}

	/*
	 * The following call may fail if an invalid ui_control is specified,
	 * or if there is no VM object associated with the control object.  In
	 * either case, reacting to it as if there were no pages resident will
	 * result in correct behavior.
	 */
	kret = memory_object_pages_resident(vp->v_ubcinfo->ui_control, &has_pages_resident);

	if (kret != KERN_SUCCESS) {
		return 0;
	}

	if (has_pages_resident == TRUE) {
		return 1;
	}

	return 0;
}

/*
 * ubc_msync
 *
 * Clean and/or invalidate a range in the memory object that backs this vnode
 *
 * Parameters:	vp			The vnode whose associated ubc_info's
 *					associated memory object is to have a
 *					range invalidated within it
 *		beg_off			The start of the range, as an offset
 *		end_off			The end of the range, as an offset
 *		resid_off		The address of an off_t supplied by the
 *					caller; may be set to NULL to ignore
 *		flags			See ubc_msync_internal()
 *
 * Returns:	0			Success
 *		!0			Failure; an errno is returned
 *
 * Implicit Returns:
 *		*resid_off, modified	If non-NULL, the  contents are ALWAYS
 *					modified; they are initialized to the
 *					beg_off, and in case of an I/O error,
 *					the difference between beg_off and the
 *					current value will reflect what was
 *					able to be written before the error
 *					occurred.  If no error is returned, the
 *					value of the resid_off is undefined; do
 *					NOT use it in place of end_off if you
 *					intend to increment from the end of the
 *					last call and call iteratively.
 *
 * Notes:	see ubc_msync_internal() for more detailed information.
 *
 */
errno_t
ubc_msync(vnode_t vp, off_t beg_off, off_t end_off, off_t *resid_off, int flags)
{
	int retval;
	int io_errno = 0;

	if (resid_off) {
		*resid_off = beg_off;
	}

	retval = ubc_msync_internal(vp, beg_off, end_off, resid_off, flags, &io_errno);

	if (retval == 0 && io_errno == 0) {
		return EINVAL;
	}
	return io_errno;
}


/*
 * ubc_msync_internal
 *
 * Clean and/or invalidate a range in the memory object that backs this vnode
 *
 * Parameters:	vp			The vnode whose associated ubc_info's
 *					associated memory object is to have a
 *					range invalidated within it
 *		beg_off			The start of the range, as an offset
 *		end_off			The end of the range, as an offset
 *		resid_off		The address of an off_t supplied by the
 *					caller; may be set to NULL to ignore
 *		flags			MUST contain at least one of the flags
 *					UBC_INVALIDATE, UBC_PUSHDIRTY, or
 *					UBC_PUSHALL; if UBC_PUSHDIRTY is used,
 *					UBC_SYNC may also be specified to cause
 *					this function to block until the
 *					operation is complete.  The behavior
 *					of UBC_SYNC is otherwise undefined.
 *		io_errno		The address of an int to contain the
 *					errno from a failed I/O operation, if
 *					one occurs; may be set to NULL to
 *					ignore
 *
 * Returns:	1			Success
 *		0			Failure
 *
 * Implicit Returns:
 *		*resid_off, modified	The contents of this offset MAY be
 *					modified; in case of an I/O error, the
 *					difference between beg_off and the
 *					current value will reflect what was
 *					able to be written before the error
 *					occurred.
 *		*io_errno, modified	The contents of this offset are set to
 *					an errno, if an error occurs; if the
 *					caller supplies an io_errno parameter,
 *					they should be careful to initialize it
 *					to 0 before calling this function to
 *					enable them to distinguish an error
 *					with a valid *resid_off from an invalid
 *					one, and to avoid potentially falsely
 *					reporting an error, depending on use.
 *
 * Notes:	If there is no ubc_info associated with the vnode supplied,
 *		this function immediately returns success.
 *
 *		If the value of end_off is less than or equal to beg_off, this
 *		function immediately returns success; that is, end_off is NOT
 *		inclusive.
 *
 *		IMPORTANT: one of the flags UBC_INVALIDATE, UBC_PUSHDIRTY, or
 *		UBC_PUSHALL MUST be specified; that is, it is NOT possible to
 *		attempt to block on in-progress I/O by calling this function
 *		with UBC_PUSHDIRTY, and then later call it with just UBC_SYNC
 *		in order to block pending on the I/O already in progress.
 *
 *		The start offset is truncated to the page boundary and the
 *		size is adjusted to include the last page in the range; that
 *		is, end_off on exactly a page boundary will not change if it
 *		is rounded, and the range of bytes written will be from the
 *		truncate beg_off to the rounded (end_off - 1).
 */
static int
ubc_msync_internal(vnode_t vp, off_t beg_off, off_t end_off, off_t *resid_off, int flags, int *io_errno)
{
	memory_object_size_t    tsize;
	kern_return_t           kret;
	int request_flags = 0;
	int flush_flags   = MEMORY_OBJECT_RETURN_NONE;

	if (!UBCINFOEXISTS(vp)) {
		return 0;
	}
	if ((flags & (UBC_INVALIDATE | UBC_PUSHDIRTY | UBC_PUSHALL)) == 0) {
		return 0;
	}
	if (end_off <= beg_off) {
		return 1;
	}

	if (flags & UBC_INVALIDATE) {
		/*
		 * discard the resident pages
		 */
		request_flags = (MEMORY_OBJECT_DATA_FLUSH | MEMORY_OBJECT_DATA_NO_CHANGE);
	}

	if (flags & UBC_SYNC) {
		/*
		 * wait for all the I/O to complete before returning
		 */
		request_flags |= MEMORY_OBJECT_IO_SYNC;
	}

	if (flags & UBC_PUSHDIRTY) {
		/*
		 * we only return the dirty pages in the range
		 */
		flush_flags = MEMORY_OBJECT_RETURN_DIRTY;
	}

	if (flags & UBC_PUSHALL) {
		/*
		 * then return all the interesting pages in the range (both
		 * dirty and precious) to the pager
		 */
		flush_flags = MEMORY_OBJECT_RETURN_ALL;
	}

	beg_off = trunc_page_64(beg_off);
	end_off = round_page_64(end_off);
	tsize   = (memory_object_size_t)end_off - beg_off;

	/* flush and/or invalidate pages in the range requested */
	kret = memory_object_lock_request(vp->v_ubcinfo->ui_control,
	    beg_off, tsize,
	    (memory_object_offset_t *)resid_off,
	    io_errno, flush_flags, request_flags,
	    VM_PROT_NO_CHANGE);

	return (kret == KERN_SUCCESS) ? 1 : 0;
}


/*
 * ubc_map
 *
 * Explicitly map a vnode that has an associate ubc_info, and add a reference
 * to it for the ubc system, if there isn't one already, so it will not be
 * recycled while it's in use, and set flags on the ubc_info to indicate that
 * we have done this
 *
 * Parameters:	vp			The vnode to map
 *		flags			The mapping flags for the vnode; this
 *					will be a combination of one or more of
 *					PROT_READ, PROT_WRITE, and PROT_EXEC
 *
 * Returns:	0			Success
 *		EPERM			Permission was denied
 *
 * Notes:	An I/O reference on the vnode must already be held on entry
 *
 *		If there is no ubc_info associated with the vnode, this function
 *		will return success.
 *
 *		If a permission error occurs, this function will return
 *		failure; all other failures will cause this function to return
 *		success.
 *
 *		IMPORTANT: This is an internal use function, and its symbols
 *		are not exported, hence its error checking is not very robust.
 *		It is primarily used by:
 *
 *		o	mmap(), when mapping a file
 *		o	When mapping a shared file (a shared library in the
 *			shared segment region)
 *		o	When loading a program image during the exec process
 *
 *		...all of these uses ignore the return code, and any fault that
 *		results later because of a failure is handled in the fix-up path
 *		of the fault handler.  The interface exists primarily as a
 *		performance hint.
 *
 *		Given that third party implementation of the type of interfaces
 *		that would use this function, such as alternative executable
 *		formats, etc., are unsupported, this function is not exported
 *		for general use.
 *
 *		The extra reference is held until the VM system unmaps the
 *		vnode from its own context to maintain a vnode reference in
 *		cases like open()/mmap()/close(), which leave the backing
 *		object referenced by a mapped memory region in a process
 *		address space.
 */
__private_extern__ int
ubc_map(vnode_t vp, int flags)
{
	struct ubc_info *uip;
	int error = 0;
	int need_ref = 0;
	int need_wakeup = 0;

	if (UBCINFOEXISTS(vp)) {
		vnode_lock(vp);
		uip = vp->v_ubcinfo;

		while (ISSET(uip->ui_flags, UI_MAPBUSY)) {
			SET(uip->ui_flags, UI_MAPWAITING);
			(void) msleep(&uip->ui_flags, &vp->v_lock,
			    PRIBIO, "ubc_map", NULL);
		}
		SET(uip->ui_flags, UI_MAPBUSY);
		vnode_unlock(vp);

		error = VNOP_MMAP(vp, flags, vfs_context_current());

		/*
		 * rdar://problem/22587101 required that we stop propagating
		 * EPERM up the stack. Otherwise, we would have to funnel up
		 * the error at all the call sites for memory_object_map().
		 * The risk is in having to undo the map/object/entry state at
		 * all these call sites. It would also affect more than just mmap()
		 * e.g. vm_remap().
		 *
		 *	if (error != EPERM)
		 *              error = 0;
		 */

		error = 0;

		vnode_lock_spin(vp);

		if (error == 0) {
			if (!ISSET(uip->ui_flags, UI_ISMAPPED)) {
				need_ref = 1;
			}
			SET(uip->ui_flags, (UI_WASMAPPED | UI_ISMAPPED));
			if (flags & PROT_WRITE) {
				SET(uip->ui_flags, (UI_WASMAPPEDWRITE | UI_MAPPEDWRITE));
			}
		}
		CLR(uip->ui_flags, UI_MAPBUSY);

		if (ISSET(uip->ui_flags, UI_MAPWAITING)) {
			CLR(uip->ui_flags, UI_MAPWAITING);
			need_wakeup = 1;
		}
		vnode_unlock(vp);

		if (need_wakeup) {
			wakeup(&uip->ui_flags);
		}

		if (need_ref) {
			/*
			 * Make sure we get a ref as we can't unwind from here
			 */
			if (vnode_ref_ext(vp, 0, VNODE_REF_FORCE)) {
				panic("%s : VNODE_REF_FORCE failed", __FUNCTION__);
			}
			/*
			 * Vnodes that are on "unreliable" media (like disk
			 * images, network filesystems, 3rd-party filesystems,
			 * and possibly external devices) could see their
			 * contents be changed via the backing store without
			 * triggering copy-on-write, so we can't fully rely
			 * on copy-on-write and might have to resort to
			 * copy-on-read to protect "privileged" processes and
			 * prevent privilege escalation.
			 *
			 * The root filesystem is considered "reliable" because
			 * there's not much point in trying to protect
			 * ourselves from such a vulnerability and the extra
			 * cost of copy-on-read (CPU time and memory pressure)
			 * could result in some serious regressions.
			 */
			if (vp->v_mount != NULL &&
			    ((vp->v_mount->mnt_flag & MNT_ROOTFS) ||
			    vnode_on_reliable_media(vp))) {
				/*
				 * This vnode is deemed "reliable" so mark
				 * its VM object as "trusted".
				 */
				memory_object_mark_trusted(uip->ui_control);
			} else {
//				printf("BUGGYCOW: %s:%d vp %p \"%s\" in mnt %p \"%s\" is untrusted\n", __FUNCTION__, __LINE__, vp, vp->v_name, vp->v_mount, vp->v_mount->mnt_vnodecovered->v_name);
			}
		}
	}
	return error;
}


/*
 * ubc_destroy_named
 *
 * Destroy the named memory object associated with the ubc_info control object
 * associated with the designated vnode, if there is a ubc_info associated
 * with the vnode, and a control object is associated with it
 *
 * Parameters:	vp			The designated vnode
 *
 * Returns:	(void)
 *
 * Notes:	This function is called on vnode termination for all vnodes,
 *		and must therefore not assume that there is a ubc_info that is
 *		associated with the vnode, nor that there is a control object
 *		associated with the ubc_info.
 *
 *		If all the conditions necessary are present, this function
 *		calls memory_object_destory(), which will in turn end up
 *		calling ubc_unmap() to release any vnode references that were
 *		established via ubc_map().
 *
 *		IMPORTANT: This is an internal use function that is used
 *		exclusively by the internal use function vclean().
 */
__private_extern__ void
ubc_destroy_named(vnode_t vp)
{
	memory_object_control_t control;
	struct ubc_info *uip;
	kern_return_t kret;

	if (UBCINFOEXISTS(vp)) {
		uip = vp->v_ubcinfo;

		/* Terminate the memory object  */
		control = ubc_getobject(vp, UBC_HOLDOBJECT);
		if (control != MEMORY_OBJECT_CONTROL_NULL) {
			kret = memory_object_destroy(control, 0);
			if (kret != KERN_SUCCESS) {
				panic("ubc_destroy_named: memory_object_destroy failed");
			}
		}
	}
}


/*
 * ubc_isinuse
 *
 * Determine whether or not a vnode is currently in use by ubc at a level in
 * excess of the requested busycount
 *
 * Parameters:	vp			The vnode to check
 *		busycount		The threshold busy count, used to bias
 *					the count usually already held by the
 *					caller to avoid races
 *
 * Returns:	1			The vnode is in use over the threshold
 *		0			The vnode is not in use over the
 *					threshold
 *
 * Notes:	Because the vnode is only held locked while actually asking
 *		the use count, this function only represents a snapshot of the
 *		current state of the vnode.  If more accurate information is
 *		required, an additional busycount should be held by the caller
 *		and a non-zero busycount used.
 *
 *		If there is no ubc_info associated with the vnode, this
 *		function will report that the vnode is not in use by ubc.
 */
int
ubc_isinuse(struct vnode *vp, int busycount)
{
	if (!UBCINFOEXISTS(vp)) {
		return 0;
	}
	return ubc_isinuse_locked(vp, busycount, 0);
}


/*
 * ubc_isinuse_locked
 *
 * Determine whether or not a vnode is currently in use by ubc at a level in
 * excess of the requested busycount
 *
 * Parameters:	vp			The vnode to check
 *		busycount		The threshold busy count, used to bias
 *					the count usually already held by the
 *					caller to avoid races
 *		locked			True if the vnode is already locked by
 *					the caller
 *
 * Returns:	1			The vnode is in use over the threshold
 *		0			The vnode is not in use over the
 *					threshold
 *
 * Notes:	If the vnode is not locked on entry, it is locked while
 *		actually asking the use count.  If this is the case, this
 *		function only represents a snapshot of the current state of
 *		the vnode.  If more accurate information is required, the
 *		vnode lock should be held by the caller, otherwise an
 *		additional busycount should be held by the caller and a
 *		non-zero busycount used.
 *
 *		If there is no ubc_info associated with the vnode, this
 *		function will report that the vnode is not in use by ubc.
 */
int
ubc_isinuse_locked(struct vnode *vp, int busycount, int locked)
{
	int retval = 0;


	if (!locked) {
		vnode_lock_spin(vp);
	}

	if ((vp->v_usecount - vp->v_kusecount) > busycount) {
		retval = 1;
	}

	if (!locked) {
		vnode_unlock(vp);
	}
	return retval;
}


/*
 * ubc_unmap
 *
 * Reverse the effects of a ubc_map() call for a given vnode
 *
 * Parameters:	vp			vnode to unmap from ubc
 *
 * Returns:	(void)
 *
 * Notes:	This is an internal use function used by vnode_pager_unmap().
 *		It will attempt to obtain a reference on the supplied vnode,
 *		and if it can do so, and there is an associated ubc_info, and
 *		the flags indicate that it was mapped via ubc_map(), then the
 *		flag is cleared, the mapping removed, and the reference taken
 *		by ubc_map() is released.
 *
 *		IMPORTANT: This MUST only be called by the VM
 *		to prevent race conditions.
 */
__private_extern__ void
ubc_unmap(struct vnode *vp)
{
	struct ubc_info *uip;
	int     need_rele = 0;
	int     need_wakeup = 0;

	if (vnode_getwithref(vp)) {
		return;
	}

	if (UBCINFOEXISTS(vp)) {
		bool want_fsevent = false;

		vnode_lock(vp);
		uip = vp->v_ubcinfo;

		while (ISSET(uip->ui_flags, UI_MAPBUSY)) {
			SET(uip->ui_flags, UI_MAPWAITING);
			(void) msleep(&uip->ui_flags, &vp->v_lock,
			    PRIBIO, "ubc_unmap", NULL);
		}
		SET(uip->ui_flags, UI_MAPBUSY);

		if (ISSET(uip->ui_flags, UI_ISMAPPED)) {
			if (ISSET(uip->ui_flags, UI_MAPPEDWRITE)) {
				want_fsevent = true;
			}

			need_rele = 1;

			/*
			 * We want to clear the mapped flags after we've called
			 * VNOP_MNOMAP to avoid certain races and allow
			 * VNOP_MNOMAP to call ubc_is_mapped_writable.
			 */
		}
		vnode_unlock(vp);

		if (need_rele) {
			vfs_context_t ctx = vfs_context_current();

			(void)VNOP_MNOMAP(vp, ctx);

#if CONFIG_FSE
			/*
			 * Why do we want an fsevent here?  Normally the
			 * content modified fsevent is posted when a file is
			 * closed and only if it's written to via conventional
			 * means.  It's perfectly legal to close a file and
			 * keep your mappings and we don't currently track
			 * whether it was written to via a mapping.
			 * Therefore, we need to post an fsevent here if the
			 * file was mapped writable.  This may result in false
			 * events, i.e. we post a notification when nothing
			 * has really changed.
			 */
			if (want_fsevent && need_fsevent(FSE_CONTENT_MODIFIED, vp)) {
				add_fsevent(FSE_CONTENT_MODIFIED_NO_HLINK, ctx,
				    FSE_ARG_VNODE, vp,
				    FSE_ARG_DONE);
			}
#endif

			vnode_rele(vp);
		}

		vnode_lock_spin(vp);

		if (need_rele) {
			CLR(uip->ui_flags, UI_ISMAPPED | UI_MAPPEDWRITE);
		}

		CLR(uip->ui_flags, UI_MAPBUSY);

		if (ISSET(uip->ui_flags, UI_MAPWAITING)) {
			CLR(uip->ui_flags, UI_MAPWAITING);
			need_wakeup = 1;
		}
		vnode_unlock(vp);

		if (need_wakeup) {
			wakeup(&uip->ui_flags);
		}
	}
	/*
	 * the drop of the vnode ref will cleanup
	 */
	vnode_put(vp);
}


/*
 * ubc_page_op
 *
 * Manipulate individual page state for a vnode with an associated ubc_info
 * with an associated memory object control.
 *
 * Parameters:	vp			The vnode backing the page
 *		f_offset		A file offset interior to the page
 *		ops			The operations to perform, as a bitmap
 *					(see below for more information)
 *		phys_entryp		The address of a ppnum_t; may be NULL
 *					to ignore
 *		flagsp			A pointer to an int to contain flags;
 *					may be NULL to ignore
 *
 * Returns:	KERN_SUCCESS		Success
 *		KERN_INVALID_ARGUMENT	If the memory object control has no VM
 *					object associated
 *		KERN_INVALID_OBJECT	If UPL_POP_PHYSICAL and the object is
 *					not physically contiguous
 *		KERN_INVALID_OBJECT	If !UPL_POP_PHYSICAL and the object is
 *					physically contiguous
 *		KERN_FAILURE		If the page cannot be looked up
 *
 * Implicit Returns:
 *		*phys_entryp (modified)	If phys_entryp is non-NULL and
 *					UPL_POP_PHYSICAL
 *		*flagsp (modified)	If flagsp is non-NULL and there was
 *					!UPL_POP_PHYSICAL and a KERN_SUCCESS
 *
 * Notes:	For object boundaries, it is considerably more efficient to
 *		ensure that f_offset is in fact on a page boundary, as this
 *		will avoid internal use of the hash table to identify the
 *		page, and would therefore skip a number of early optimizations.
 *		Since this is a page operation anyway, the caller should try
 *		to pass only a page aligned offset because of this.
 *
 *		*flagsp may be modified even if this function fails.  If it is
 *		modified, it will contain the condition of the page before the
 *		requested operation was attempted; these will only include the
 *		bitmap flags, and not the PL_POP_PHYSICAL, UPL_POP_DUMP,
 *		UPL_POP_SET, or UPL_POP_CLR bits.
 *
 *		The flags field may contain a specific operation, such as
 *		UPL_POP_PHYSICAL or UPL_POP_DUMP:
 *
 *		o	UPL_POP_PHYSICAL	Fail if not contiguous; if
 *						*phys_entryp and successful, set
 *						*phys_entryp
 *		o	UPL_POP_DUMP		Dump the specified page
 *
 *		Otherwise, it is treated as a bitmap of one or more page
 *		operations to perform on the final memory object; allowable
 *		bit values are:
 *
 *		o	UPL_POP_DIRTY		The page is dirty
 *		o	UPL_POP_PAGEOUT		The page is paged out
 *		o	UPL_POP_PRECIOUS	The page is precious
 *		o	UPL_POP_ABSENT		The page is absent
 *		o	UPL_POP_BUSY		The page is busy
 *
 *		If the page status is only being queried and not modified, then
 *		not other bits should be specified.  However, if it is being
 *		modified, exactly ONE of the following bits should be set:
 *
 *		o	UPL_POP_SET		Set the current bitmap bits
 *		o	UPL_POP_CLR		Clear the current bitmap bits
 *
 *		Thus to effect a combination of setting an clearing, it may be
 *		necessary to call this function twice.  If this is done, the
 *		set should be used before the clear, since clearing may trigger
 *		a wakeup on the destination page, and if the page is backed by
 *		an encrypted swap file, setting will trigger the decryption
 *		needed before the wakeup occurs.
 */
kern_return_t
ubc_page_op(
	struct vnode    *vp,
	off_t           f_offset,
	int             ops,
	ppnum_t *phys_entryp,
	int             *flagsp)
{
	memory_object_control_t         control;

	control = ubc_getobject(vp, UBC_FLAGS_NONE);
	if (control == MEMORY_OBJECT_CONTROL_NULL) {
		return KERN_INVALID_ARGUMENT;
	}

	return memory_object_page_op(control,
	           (memory_object_offset_t)f_offset,
	           ops,
	           phys_entryp,
	           flagsp);
}


/*
 * ubc_range_op
 *
 * Manipulate page state for a range of memory for a vnode with an associated
 * ubc_info with an associated memory object control, when page level state is
 * not required to be returned from the call (i.e. there are no phys_entryp or
 * flagsp parameters to this call, and it takes a range which may contain
 * multiple pages, rather than an offset interior to a single page).
 *
 * Parameters:	vp			The vnode backing the page
 *		f_offset_beg		A file offset interior to the start page
 *		f_offset_end		A file offset interior to the end page
 *		ops			The operations to perform, as a bitmap
 *					(see below for more information)
 *		range			The address of an int; may be NULL to
 *					ignore
 *
 * Returns:	KERN_SUCCESS		Success
 *		KERN_INVALID_ARGUMENT	If the memory object control has no VM
 *					object associated
 *		KERN_INVALID_OBJECT	If the object is physically contiguous
 *
 * Implicit Returns:
 *		*range (modified)	If range is non-NULL, its contents will
 *					be modified to contain the number of
 *					bytes successfully operated upon.
 *
 * Notes:	IMPORTANT: This function cannot be used on a range that
 *		consists of physically contiguous pages.
 *
 *		For object boundaries, it is considerably more efficient to
 *		ensure that f_offset_beg and f_offset_end are in fact on page
 *		boundaries, as this will avoid internal use of the hash table
 *		to identify the page, and would therefore skip a number of
 *		early optimizations.  Since this is an operation on a set of
 *		pages anyway, the caller should try to pass only a page aligned
 *		offsets because of this.
 *
 *		*range will be modified only if this function succeeds.
 *
 *		The flags field MUST contain a specific operation; allowable
 *		values are:
 *
 *		o	UPL_ROP_ABSENT	Returns the extent of the range
 *					presented which is absent, starting
 *					with the start address presented
 *
 *		o	UPL_ROP_PRESENT	Returns the extent of the range
 *					presented which is present (resident),
 *					starting with the start address
 *					presented
 *		o	UPL_ROP_DUMP	Dump the pages which are found in the
 *					target object for the target range.
 *
 *		IMPORTANT: For UPL_ROP_ABSENT and UPL_ROP_PRESENT; if there are
 *		multiple regions in the range, only the first matching region
 *		is returned.
 */
kern_return_t
ubc_range_op(
	struct vnode    *vp,
	off_t           f_offset_beg,
	off_t           f_offset_end,
	int             ops,
	int             *range)
{
	memory_object_control_t         control;

	control = ubc_getobject(vp, UBC_FLAGS_NONE);
	if (control == MEMORY_OBJECT_CONTROL_NULL) {
		return KERN_INVALID_ARGUMENT;
	}

	return memory_object_range_op(control,
	           (memory_object_offset_t)f_offset_beg,
	           (memory_object_offset_t)f_offset_end,
	           ops,
	           range);
}


/*
 * ubc_create_upl
 *
 * Given a vnode, cause the population of a portion of the vm_object; based on
 * the nature of the request, the pages returned may contain valid data, or
 * they may be uninitialized.
 *
 * Parameters:	vp			The vnode from which to create the upl
 *		f_offset		The start offset into the backing store
 *					represented by the vnode
 *		bufsize			The size of the upl to create
 *		uplp			Pointer to the upl_t to receive the
 *					created upl; MUST NOT be NULL
 *		plp			Pointer to receive the internal page
 *					list for the created upl; MAY be NULL
 *					to ignore
 *
 * Returns:	KERN_SUCCESS		The requested upl has been created
 *		KERN_INVALID_ARGUMENT	The bufsize argument is not an even
 *					multiple of the page size
 *		KERN_INVALID_ARGUMENT	There is no ubc_info associated with
 *					the vnode, or there is no memory object
 *					control associated with the ubc_info
 *	memory_object_upl_request:KERN_INVALID_VALUE
 *					The supplied upl_flags argument is
 *					invalid
 * Implicit Returns:
 *		*uplp (modified)
 *		*plp (modified)		If non-NULL, the value of *plp will be
 *					modified to point to the internal page
 *					list; this modification may occur even
 *					if this function is unsuccessful, in
 *					which case the contents may be invalid
 *
 * Note:	If successful, the returned *uplp MUST subsequently be freed
 *		via a call to ubc_upl_commit(), ubc_upl_commit_range(),
 *		ubc_upl_abort(), or ubc_upl_abort_range().
 */
kern_return_t
ubc_create_upl_external(
	struct vnode    *vp,
	off_t           f_offset,
	int             bufsize,
	upl_t           *uplp,
	upl_page_info_t **plp,
	int             uplflags)
{
	return ubc_create_upl_kernel(vp, f_offset, bufsize, uplp, plp, uplflags, vm_tag_bt());
}

kern_return_t
ubc_create_upl_kernel(
	struct vnode    *vp,
	off_t           f_offset,
	int             bufsize,
	upl_t           *uplp,
	upl_page_info_t **plp,
	int             uplflags,
	vm_tag_t tag)
{
	memory_object_control_t         control;
	kern_return_t                   kr;

	if (plp != NULL) {
		*plp = NULL;
	}
	*uplp = NULL;

	if (bufsize & 0xfff) {
		return KERN_INVALID_ARGUMENT;
	}

	if (bufsize > MAX_UPL_SIZE_BYTES) {
		return KERN_INVALID_ARGUMENT;
	}

	if (uplflags & (UPL_UBC_MSYNC | UPL_UBC_PAGEOUT | UPL_UBC_PAGEIN)) {
		if (uplflags & UPL_UBC_MSYNC) {
			uplflags &= UPL_RET_ONLY_DIRTY;

			uplflags |= UPL_COPYOUT_FROM | UPL_CLEAN_IN_PLACE |
			    UPL_SET_INTERNAL | UPL_SET_LITE;
		} else if (uplflags & UPL_UBC_PAGEOUT) {
			uplflags &= UPL_RET_ONLY_DIRTY;

			if (uplflags & UPL_RET_ONLY_DIRTY) {
				uplflags |= UPL_NOBLOCK;
			}

			uplflags |= UPL_FOR_PAGEOUT | UPL_CLEAN_IN_PLACE |
			    UPL_COPYOUT_FROM | UPL_SET_INTERNAL | UPL_SET_LITE;
		} else {
			uplflags |= UPL_RET_ONLY_ABSENT |
			    UPL_NO_SYNC | UPL_CLEAN_IN_PLACE |
			    UPL_SET_INTERNAL | UPL_SET_LITE;

			/*
			 * if the requested size == PAGE_SIZE, we don't want to set
			 * the UPL_NOBLOCK since we may be trying to recover from a
			 * previous partial pagein I/O that occurred because we were low
			 * on memory and bailed early in order to honor the UPL_NOBLOCK...
			 * since we're only asking for a single page, we can block w/o fear
			 * of tying up pages while waiting for more to become available
			 */
			if (bufsize > PAGE_SIZE) {
				uplflags |= UPL_NOBLOCK;
			}
		}
	} else {
		uplflags &= ~UPL_FOR_PAGEOUT;

		if (uplflags & UPL_WILL_BE_DUMPED) {
			uplflags &= ~UPL_WILL_BE_DUMPED;
			uplflags |= (UPL_NO_SYNC | UPL_SET_INTERNAL);
		} else {
			uplflags |= (UPL_NO_SYNC | UPL_CLEAN_IN_PLACE | UPL_SET_INTERNAL);
		}
	}
	control = ubc_getobject(vp, UBC_FLAGS_NONE);
	if (control == MEMORY_OBJECT_CONTROL_NULL) {
		return KERN_INVALID_ARGUMENT;
	}

	kr = memory_object_upl_request(control, f_offset, bufsize, uplp, NULL, NULL, uplflags, tag);
	if (kr == KERN_SUCCESS && plp != NULL) {
		*plp = UPL_GET_INTERNAL_PAGE_LIST(*uplp);
	}
	return kr;
}


/*
 * ubc_upl_maxbufsize
 *
 * Return the maximum bufsize ubc_create_upl( ) will take.
 *
 * Parameters:	none
 *
 * Returns:	maximum size buffer (in bytes) ubc_create_upl( ) will take.
 */
upl_size_t
ubc_upl_maxbufsize(
	void)
{
	return MAX_UPL_SIZE_BYTES;
}

/*
 * ubc_upl_map
 *
 * Map the page list assocated with the supplied upl into the kernel virtual
 * address space at the virtual address indicated by the dst_addr argument;
 * the entire upl is mapped
 *
 * Parameters:	upl			The upl to map
 *		dst_addr		The address at which to map the upl
 *
 * Returns:	KERN_SUCCESS		The upl has been mapped
 *		KERN_INVALID_ARGUMENT	The upl is UPL_NULL
 *		KERN_FAILURE		The upl is already mapped
 *	vm_map_enter:KERN_INVALID_ARGUMENT
 *					A failure code from vm_map_enter() due
 *					to an invalid argument
 */
kern_return_t
ubc_upl_map(
	upl_t           upl,
	vm_offset_t     *dst_addr)
{
	return vm_upl_map(kernel_map, upl, dst_addr);
}

/*
 * ubc_upl_map_range:- similar to ubc_upl_map but the focus is on a range
 * of the UPL. Takes an offset, size, and protection so that only a  part
 * of the UPL can be mapped with the right protections.
 */
kern_return_t
ubc_upl_map_range(
	upl_t           upl,
	vm_offset_t     offset_to_map,
	vm_size_t       size_to_map,
	vm_prot_t       prot_to_map,
	vm_offset_t     *dst_addr)
{
	return vm_upl_map_range(kernel_map, upl, offset_to_map, size_to_map, prot_to_map, dst_addr);
}


/*
 * ubc_upl_unmap
 *
 * Unmap the page list assocated with the supplied upl from the kernel virtual
 * address space; the entire upl is unmapped.
 *
 * Parameters:	upl			The upl to unmap
 *
 * Returns:	KERN_SUCCESS		The upl has been unmapped
 *		KERN_FAILURE		The upl is not currently mapped
 *		KERN_INVALID_ARGUMENT	If the upl is UPL_NULL
 */
kern_return_t
ubc_upl_unmap(
	upl_t   upl)
{
	return vm_upl_unmap(kernel_map, upl);
}

/*
 * ubc_upl_unmap_range:- similar to ubc_upl_unmap but the focus is
 * on part of the UPL that is mapped. The offset and size parameter
 * specifies what part of the UPL needs to be unmapped.
 *
 * Note: Currrently offset & size are unused as we always initiate the unmap from the
 * very beginning of the UPL's mapping and track the mapped size in the UPL. But we
 * might want to allow unmapping a UPL in the middle, for example, and we can use the
 * offset + size parameters for that purpose.
 */
kern_return_t
ubc_upl_unmap_range(
	upl_t   upl,
	vm_offset_t     offset_to_unmap,
	vm_size_t       size_to_unmap)
{
	return vm_upl_unmap_range(kernel_map, upl, offset_to_unmap, size_to_unmap);
}


/*
 * ubc_upl_commit
 *
 * Commit the contents of the upl to the backing store
 *
 * Parameters:	upl			The upl to commit
 *
 * Returns:	KERN_SUCCESS		The upl has been committed
 *		KERN_INVALID_ARGUMENT	The supplied upl was UPL_NULL
 *		KERN_FAILURE		The supplied upl does not represent
 *					device memory, and the offset plus the
 *					size would exceed the actual size of
 *					the upl
 *
 * Notes:	In practice, the only return value for this function should be
 *		KERN_SUCCESS, unless there has been data structure corruption;
 *		since the upl is deallocated regardless of success or failure,
 *		there's really nothing to do about this other than panic.
 *
 *		IMPORTANT: Use of this function should not be mixed with use of
 *		ubc_upl_commit_range(), due to the unconditional deallocation
 *		by this function.
 */
kern_return_t
ubc_upl_commit(
	upl_t                   upl)
{
	upl_page_info_t *pl;
	kern_return_t   kr;

	pl = UPL_GET_INTERNAL_PAGE_LIST(upl);
	kr = upl_commit(upl, pl, MAX_UPL_SIZE_BYTES >> PAGE_SHIFT);
	upl_deallocate(upl);
	return kr;
}


/*
 * ubc_upl_commit
 *
 * Commit the contents of the specified range of the upl to the backing store
 *
 * Parameters:	upl			The upl to commit
 *		offset			The offset into the upl
 *		size			The size of the region to be committed,
 *					starting at the specified offset
 *		flags			commit type (see below)
 *
 * Returns:	KERN_SUCCESS		The range has been committed
 *		KERN_INVALID_ARGUMENT	The supplied upl was UPL_NULL
 *		KERN_FAILURE		The supplied upl does not represent
 *					device memory, and the offset plus the
 *					size would exceed the actual size of
 *					the upl
 *
 * Notes:	IMPORTANT: If the commit is successful, and the object is now
 *		empty, the upl will be deallocated.  Since the caller cannot
 *		check that this is the case, the UPL_COMMIT_FREE_ON_EMPTY flag
 *		should generally only be used when the offset is 0 and the size
 *		is equal to the upl size.
 *
 *		The flags argument is a bitmap of flags on the rage of pages in
 *		the upl to be committed; allowable flags are:
 *
 *		o	UPL_COMMIT_FREE_ON_EMPTY	Free the upl when it is
 *							both empty and has been
 *							successfully committed
 *		o	UPL_COMMIT_CLEAR_DIRTY		Clear each pages dirty
 *							bit; will prevent a
 *							later pageout
 *		o	UPL_COMMIT_SET_DIRTY		Set each pages dirty
 *							bit; will cause a later
 *							pageout
 *		o	UPL_COMMIT_INACTIVATE		Clear each pages
 *							reference bit; the page
 *							will not be accessed
 *		o	UPL_COMMIT_ALLOW_ACCESS		Unbusy each page; pages
 *							become busy when an
 *							IOMemoryDescriptor is
 *							mapped or redirected,
 *							and we have to wait for
 *							an IOKit driver
 *
 *		The flag UPL_COMMIT_NOTIFY_EMPTY is used internally, and should
 *		not be specified by the caller.
 *
 *		The UPL_COMMIT_CLEAR_DIRTY and UPL_COMMIT_SET_DIRTY flags are
 *		mutually exclusive, and should not be combined.
 */
kern_return_t
ubc_upl_commit_range(
	upl_t                   upl,
	upl_offset_t            offset,
	upl_size_t              size,
	int                             flags)
{
	upl_page_info_t *pl;
	boolean_t               empty;
	kern_return_t   kr;

	if (flags & UPL_COMMIT_FREE_ON_EMPTY) {
		flags |= UPL_COMMIT_NOTIFY_EMPTY;
	}

	if (flags & UPL_COMMIT_KERNEL_ONLY_FLAGS) {
		return KERN_INVALID_ARGUMENT;
	}

	pl = UPL_GET_INTERNAL_PAGE_LIST(upl);

	kr = upl_commit_range(upl, offset, size, flags,
	    pl, MAX_UPL_SIZE_BYTES >> PAGE_SHIFT, &empty);

	if ((flags & UPL_COMMIT_FREE_ON_EMPTY) && empty) {
		upl_deallocate(upl);
	}

	return kr;
}


/*
 * ubc_upl_abort_range
 *
 * Abort the contents of the specified range of the specified upl
 *
 * Parameters:	upl			The upl to abort
 *		offset			The offset into the upl
 *		size			The size of the region to be aborted,
 *					starting at the specified offset
 *		abort_flags		abort type (see below)
 *
 * Returns:	KERN_SUCCESS		The range has been aborted
 *		KERN_INVALID_ARGUMENT	The supplied upl was UPL_NULL
 *		KERN_FAILURE		The supplied upl does not represent
 *					device memory, and the offset plus the
 *					size would exceed the actual size of
 *					the upl
 *
 * Notes:	IMPORTANT: If the abort is successful, and the object is now
 *		empty, the upl will be deallocated.  Since the caller cannot
 *		check that this is the case, the UPL_ABORT_FREE_ON_EMPTY flag
 *		should generally only be used when the offset is 0 and the size
 *		is equal to the upl size.
 *
 *		The abort_flags argument is a bitmap of flags on the range of
 *		pages in the upl to be aborted; allowable flags are:
 *
 *		o	UPL_ABORT_FREE_ON_EMPTY	Free the upl when it is both
 *						empty and has been successfully
 *						aborted
 *		o	UPL_ABORT_RESTART	The operation must be restarted
 *		o	UPL_ABORT_UNAVAILABLE	The pages are unavailable
 *		o	UPL_ABORT_ERROR		An I/O error occurred
 *		o	UPL_ABORT_DUMP_PAGES	Just free the pages
 *		o	UPL_ABORT_NOTIFY_EMPTY	RESERVED
 *		o	UPL_ABORT_ALLOW_ACCESS	RESERVED
 *
 *		The UPL_ABORT_NOTIFY_EMPTY is an internal use flag and should
 *		not be specified by the caller.  It is intended to fulfill the
 *		same role as UPL_COMMIT_NOTIFY_EMPTY does in the function
 *		ubc_upl_commit_range(), but is never referenced internally.
 *
 *		The UPL_ABORT_ALLOW_ACCESS is defined, but neither set nor
 *		referenced; do not use it.
 */
kern_return_t
ubc_upl_abort_range(
	upl_t                   upl,
	upl_offset_t            offset,
	upl_size_t              size,
	int                             abort_flags)
{
	kern_return_t   kr;
	boolean_t               empty = FALSE;

	if (abort_flags & UPL_ABORT_FREE_ON_EMPTY) {
		abort_flags |= UPL_ABORT_NOTIFY_EMPTY;
	}

	kr = upl_abort_range(upl, offset, size, abort_flags, &empty);

	if ((abort_flags & UPL_ABORT_FREE_ON_EMPTY) && empty) {
		upl_deallocate(upl);
	}

	return kr;
}


/*
 * ubc_upl_abort
 *
 * Abort the contents of the specified upl
 *
 * Parameters:	upl			The upl to abort
 *		abort_type		abort type (see below)
 *
 * Returns:	KERN_SUCCESS		The range has been aborted
 *		KERN_INVALID_ARGUMENT	The supplied upl was UPL_NULL
 *		KERN_FAILURE		The supplied upl does not represent
 *					device memory, and the offset plus the
 *					size would exceed the actual size of
 *					the upl
 *
 * Notes:	IMPORTANT: If the abort is successful, and the object is now
 *		empty, the upl will be deallocated.  Since the caller cannot
 *		check that this is the case, the UPL_ABORT_FREE_ON_EMPTY flag
 *		should generally only be used when the offset is 0 and the size
 *		is equal to the upl size.
 *
 *		The abort_type is a bitmap of flags on the range of
 *		pages in the upl to be aborted; allowable flags are:
 *
 *		o	UPL_ABORT_FREE_ON_EMPTY	Free the upl when it is both
 *						empty and has been successfully
 *						aborted
 *		o	UPL_ABORT_RESTART	The operation must be restarted
 *		o	UPL_ABORT_UNAVAILABLE	The pages are unavailable
 *		o	UPL_ABORT_ERROR		An I/O error occurred
 *		o	UPL_ABORT_DUMP_PAGES	Just free the pages
 *		o	UPL_ABORT_NOTIFY_EMPTY	RESERVED
 *		o	UPL_ABORT_ALLOW_ACCESS	RESERVED
 *
 *		The UPL_ABORT_NOTIFY_EMPTY is an internal use flag and should
 *		not be specified by the caller.  It is intended to fulfill the
 *		same role as UPL_COMMIT_NOTIFY_EMPTY does in the function
 *		ubc_upl_commit_range(), but is never referenced internally.
 *
 *		The UPL_ABORT_ALLOW_ACCESS is defined, but neither set nor
 *		referenced; do not use it.
 */
kern_return_t
ubc_upl_abort(
	upl_t                   upl,
	int                             abort_type)
{
	kern_return_t   kr;

	kr = upl_abort(upl, abort_type);
	upl_deallocate(upl);
	return kr;
}


/*
 * ubc_upl_pageinfo
 *
 *  Retrieve the internal page list for the specified upl
 *
 * Parameters:	upl			The upl to obtain the page list from
 *
 * Returns:	!NULL			The (upl_page_info_t *) for the page
 *					list internal to the upl
 *		NULL			Error/no page list associated
 *
 * Notes:	IMPORTANT: The function is only valid on internal objects
 *		where the list request was made with the UPL_INTERNAL flag.
 *
 *		This function is a utility helper function, since some callers
 *		may not have direct access to the header defining the macro,
 *		due to abstraction layering constraints.
 */
upl_page_info_t *
ubc_upl_pageinfo(
	upl_t                   upl)
{
	return UPL_GET_INTERNAL_PAGE_LIST(upl);
}


int
UBCINFOEXISTS(const struct vnode * vp)
{
	return (vp) && ((vp)->v_type == VREG) && ((vp)->v_ubcinfo != UBC_INFO_NULL);
}


void
ubc_upl_range_needed(
	upl_t           upl,
	int             index,
	int             count)
{
	upl_range_needed(upl, index, count);
}

boolean_t
ubc_is_mapped(const struct vnode *vp, boolean_t *writable)
{
	if (!UBCINFOEXISTS(vp) || !ISSET(vp->v_ubcinfo->ui_flags, UI_ISMAPPED)) {
		return FALSE;
	}
	if (writable) {
		*writable = ISSET(vp->v_ubcinfo->ui_flags, UI_MAPPEDWRITE);
	}
	return TRUE;
}

boolean_t
ubc_is_mapped_writable(const struct vnode *vp)
{
	boolean_t writable;
	return ubc_is_mapped(vp, &writable) && writable;
}

boolean_t
ubc_was_mapped(const struct vnode *vp, boolean_t *writable)
{
	if (!UBCINFOEXISTS(vp) || !ISSET(vp->v_ubcinfo->ui_flags, UI_WASMAPPED)) {
		return FALSE;
	}
	if (writable) {
		*writable = ISSET(vp->v_ubcinfo->ui_flags, UI_WASMAPPEDWRITE);
	}
	return TRUE;
}

boolean_t
ubc_was_mapped_writable(const struct vnode *vp)
{
	boolean_t writable;
	return ubc_was_mapped(vp, &writable) && writable;
}


/*
 * CODE SIGNING
 */
static atomic_size_t cs_blob_size = 0;
static atomic_uint_fast32_t cs_blob_count = 0;
static atomic_size_t cs_blob_size_peak = 0;
static atomic_size_t cs_blob_size_max = 0;
static atomic_uint_fast32_t cs_blob_count_peak = 0;

SYSCTL_UINT(_vm, OID_AUTO, cs_blob_count, CTLFLAG_RD | CTLFLAG_LOCKED, &cs_blob_count, 0, "Current number of code signature blobs");
SYSCTL_ULONG(_vm, OID_AUTO, cs_blob_size, CTLFLAG_RD | CTLFLAG_LOCKED, &cs_blob_size, "Current size of all code signature blobs");
SYSCTL_UINT(_vm, OID_AUTO, cs_blob_count_peak, CTLFLAG_RD | CTLFLAG_LOCKED, &cs_blob_count_peak, 0, "Peak number of code signature blobs");
SYSCTL_ULONG(_vm, OID_AUTO, cs_blob_size_peak, CTLFLAG_RD | CTLFLAG_LOCKED, &cs_blob_size_peak, "Peak size of code signature blobs");
SYSCTL_ULONG(_vm, OID_AUTO, cs_blob_size_max, CTLFLAG_RD | CTLFLAG_LOCKED, &cs_blob_size_max, "Size of biggest code signature blob");

/*
 * Function: csblob_parse_teamid
 *
 * Description: This function returns a pointer to the team id
 *               stored within the codedirectory of the csblob.
 *               If the codedirectory predates team-ids, it returns
 *               NULL.
 *               This does not copy the name but returns a pointer to
 *               it within the CD. Subsequently, the CD must be
 *               available when this is used.
 */

static const char *
csblob_parse_teamid(struct cs_blob *csblob)
{
	const CS_CodeDirectory *cd;

	cd = csblob->csb_cd;

	if (ntohl(cd->version) < CS_SUPPORTSTEAMID) {
		return NULL;
	}

	if (cd->teamOffset == 0) {
		return NULL;
	}

	const char *name = ((const char *)cd) + ntohl(cd->teamOffset);
	if (cs_debug > 1) {
		printf("found team-id %s in cdblob\n", name);
	}

	return name;
}

kern_return_t
ubc_cs_blob_allocate(
	vm_offset_t     *blob_addr_p,
	vm_size_t       *blob_size_p)
{
	kern_return_t   kr = KERN_FAILURE;
	vm_size_t       allocation_size = 0;

	if (!blob_addr_p || !blob_size_p) {
		return KERN_INVALID_ARGUMENT;
	}
	allocation_size = *blob_size_p;

	if (ubc_cs_blob_pagewise_allocate(allocation_size) == true) {
		/* Round up to page size */
		allocation_size = round_page(allocation_size);

		/* Allocate page-wise */
		kr = kmem_alloc(
			kernel_map,
			blob_addr_p,
			allocation_size,
			KMA_KOBJECT | KMA_DATA | KMA_ZERO,
			VM_KERN_MEMORY_SECURITY);
	} else {
		*blob_addr_p = (vm_offset_t)kalloc_data_tag(
			allocation_size,
			Z_WAITOK | Z_ZERO,
			VM_KERN_MEMORY_SECURITY);

		assert(*blob_addr_p != 0);
		kr = KERN_SUCCESS;
	}

	if (kr == KERN_SUCCESS) {
		*blob_size_p = allocation_size;
	}

	return kr;
}

void
ubc_cs_blob_deallocate(
	vm_offset_t     blob_addr,
	vm_size_t       blob_size)
{
	if (ubc_cs_blob_pagewise_allocate(blob_size) == true) {
		kmem_free(kernel_map, blob_addr, blob_size);
	} else {
		kfree_data(blob_addr, blob_size);
	}
}

/*
 * Some codesigned files use a lowest common denominator page size of
 * 4KiB, but can be used on systems that have a runtime page size of
 * 16KiB. Since faults will only occur on 16KiB ranges in
 * cs_validate_range(), we can convert the original Code Directory to
 * a multi-level scheme where groups of 4 hashes are combined to form
 * a new hash, which represents 16KiB in the on-disk file.  This can
 * reduce the wired memory requirement for the Code Directory by
 * 75%. Care must be taken for binaries that use the "fourk" VM pager
 * for unaligned access, which may still attempt to validate on
 * non-16KiB multiples for compatibility with 3rd party binaries.
 */
static boolean_t
ubc_cs_supports_multilevel_hash(struct cs_blob *blob __unused)
{
	const CS_CodeDirectory *cd;

#if CODE_SIGNING_MONITOR
	// TODO: <rdar://problem/30954826>
	if (csm_enabled() == true) {
		return FALSE;
	}
#endif

	/*
	 * Only applies to binaries that ship as part of the OS,
	 * primarily the shared cache.
	 */
	if (!blob->csb_platform_binary || blob->csb_teamid != NULL) {
		return FALSE;
	}

	/*
	 * If the runtime page size matches the code signing page
	 * size, there is no work to do.
	 */
	if (PAGE_SHIFT <= blob->csb_hash_pageshift) {
		return FALSE;
	}

	cd = blob->csb_cd;

	/*
	 * There must be a valid integral multiple of hashes
	 */
	if (ntohl(cd->nCodeSlots) & (PAGE_MASK >> blob->csb_hash_pageshift)) {
		return FALSE;
	}

	/*
	 * Scatter lists must also have ranges that have an integral number of hashes
	 */
	if ((ntohl(cd->version) >= CS_SUPPORTSSCATTER) && (ntohl(cd->scatterOffset))) {
		const SC_Scatter *scatter = (const SC_Scatter*)
		    ((const char*)cd + ntohl(cd->scatterOffset));
		/* iterate all scatter structs to make sure they are all aligned */
		do {
			uint32_t sbase = ntohl(scatter->base);
			uint32_t scount = ntohl(scatter->count);

			/* last scatter? */
			if (scount == 0) {
				break;
			}

			if (sbase & (PAGE_MASK >> blob->csb_hash_pageshift)) {
				return FALSE;
			}

			if (scount & (PAGE_MASK >> blob->csb_hash_pageshift)) {
				return FALSE;
			}

			scatter++;
		} while (1);
	}

	/* Covered range must be a multiple of the new page size */
	if (ntohl(cd->codeLimit) & PAGE_MASK) {
		return FALSE;
	}

	/* All checks pass */
	return TRUE;
}

/*
 * Reconstruct a cs_blob with the code signature fields. This helper function
 * is useful because a lot of things often change the base address of the code
 * signature blob, which requires reconstructing some of the other pointers
 * within.
 */
static errno_t
ubc_cs_blob_reconstruct(
	struct cs_blob *cs_blob,
	const vm_address_t signature_addr,
	const vm_address_t signature_size,
	const vm_offset_t code_directory_offset)
{
	const CS_CodeDirectory *code_directory = NULL;

	/* Setup the signature blob address */
	cs_blob->csb_mem_kaddr = (void*)signature_addr;
	cs_blob->csb_mem_size = signature_size;

	/* Setup the code directory in the blob */
	code_directory = (const CS_CodeDirectory*)(signature_addr + code_directory_offset);
	cs_blob->csb_cd = code_directory;

	/* Setup the XML entitlements */
	cs_blob->csb_entitlements_blob = csblob_find_blob_bytes(
		(uint8_t*)signature_addr,
		signature_size,
		CSSLOT_ENTITLEMENTS,
		CSMAGIC_EMBEDDED_ENTITLEMENTS);

	/* Setup the DER entitlements */
	cs_blob->csb_der_entitlements_blob = csblob_find_blob_bytes(
		(uint8_t*)signature_addr,
		signature_size,
		CSSLOT_DER_ENTITLEMENTS,
		CSMAGIC_EMBEDDED_DER_ENTITLEMENTS);

	return 0;
}

/*
 * Given a validated cs_blob, we reformat the structure to only include
 * the blobs which are required by the kernel for our current platform.
 * This saves significant memory with agile signatures.
 *
 * To support rewriting the code directory, potentially through
 * multilevel hashes, we provide a mechanism to allocate a code directory
 * of a specified size and zero it out --> caller can fill it in.
 *
 * We don't need to perform a lot of overflow checks as the assumption
 * here is that the cs_blob has already been validated.
 */
static errno_t
ubc_cs_reconstitute_code_signature(
	const struct cs_blob * const blob,
	vm_address_t * const ret_mem_kaddr,
	vm_size_t * const ret_mem_size,
	vm_size_t code_directory_size,
	CS_CodeDirectory ** const code_directory
	)
{
	vm_address_t new_blob_addr = 0;
	vm_size_t new_blob_size = 0;
	vm_size_t new_code_directory_size = 0;
	const CS_GenericBlob *best_code_directory = NULL;
	const CS_GenericBlob *first_code_directory = NULL;
	const CS_GenericBlob *der_entitlements_blob = NULL;
	const CS_GenericBlob *entitlements_blob = NULL;
	const CS_GenericBlob *cms_blob = NULL;
	const CS_GenericBlob *launch_constraint_self = NULL;
	const CS_GenericBlob *launch_constraint_parent = NULL;
	const CS_GenericBlob *launch_constraint_responsible = NULL;
	CS_SuperBlob *superblob = NULL;
	uint32_t num_blobs = 0;
	uint32_t blob_index = 0;
	uint32_t blob_offset = 0;
	kern_return_t ret;
	int err;

	if (!blob) {
		if (cs_debug > 1) {
			printf("CODE SIGNING: CS Blob passed in is NULL\n");
		}
		return EINVAL;
	}

	best_code_directory = (const CS_GenericBlob*)blob->csb_cd;
	if (!best_code_directory) {
		/* This case can never happen, and it is a sign of bad things */
		panic("CODE SIGNING: Validated CS Blob has no code directory");
	}

	new_code_directory_size = code_directory_size;
	if (new_code_directory_size == 0) {
		new_code_directory_size = ntohl(best_code_directory->length);
	}

	/*
	 * A code signature can contain multiple code directories, each of which contains hashes
	 * of pages based on a hashing algorithm. The kernel selects which hashing algorithm is
	 * the strongest, and consequently, marks one of these code directories as the best
	 * matched one. More often than not, the best matched one is _not_ the first one.
	 *
	 * However, the CMS blob which cryptographically verifies the code signature is only
	 * signed against the first code directory. Therefore, if the CMS blob is present, we also
	 * need the first code directory to be able to verify it. Given this, we organize the
	 * new cs_blob as following order:
	 *
	 * 1. best code directory
	 * 2. DER encoded entitlements blob (if present)
	 * 3. launch constraint self (if present)
	 * 4. launch constraint parent (if present)
	 * 5. launch constraint responsible (if present)
	 * 6. entitlements blob (if present)
	 * 7. cms blob (if present)
	 * 8. first code directory (if not already the best match, and if cms blob is present)
	 *
	 * This order is chosen deliberately, as later on, we expect to get rid of the CMS blob
	 * and the first code directory once their verification is complete.
	 */

	/* Storage for the super blob header */
	new_blob_size += sizeof(CS_SuperBlob);

	/* Guaranteed storage for the best code directory */
	new_blob_size += sizeof(CS_BlobIndex);
	new_blob_size += new_code_directory_size;
	num_blobs += 1;

	/* Conditional storage for the DER entitlements blob */
	der_entitlements_blob = blob->csb_der_entitlements_blob;
	if (der_entitlements_blob) {
		new_blob_size += sizeof(CS_BlobIndex);
		new_blob_size += ntohl(der_entitlements_blob->length);
		num_blobs += 1;
	}

	/* Conditional storage for the launch constraints self blob */
	launch_constraint_self = csblob_find_blob_bytes(
		(const uint8_t *)blob->csb_mem_kaddr,
		blob->csb_mem_size,
		CSSLOT_LAUNCH_CONSTRAINT_SELF,
		CSMAGIC_EMBEDDED_LAUNCH_CONSTRAINT);
	if (launch_constraint_self) {
		new_blob_size += sizeof(CS_BlobIndex);
		new_blob_size += ntohl(launch_constraint_self->length);
		num_blobs += 1;
	}

	/* Conditional storage for the launch constraints parent blob */
	launch_constraint_parent = csblob_find_blob_bytes(
		(const uint8_t *)blob->csb_mem_kaddr,
		blob->csb_mem_size,
		CSSLOT_LAUNCH_CONSTRAINT_PARENT,
		CSMAGIC_EMBEDDED_LAUNCH_CONSTRAINT);
	if (launch_constraint_parent) {
		new_blob_size += sizeof(CS_BlobIndex);
		new_blob_size += ntohl(launch_constraint_parent->length);
		num_blobs += 1;
	}

	/* Conditional storage for the launch constraints responsible blob */
	launch_constraint_responsible = csblob_find_blob_bytes(
		(const uint8_t *)blob->csb_mem_kaddr,
		blob->csb_mem_size,
		CSSLOT_LAUNCH_CONSTRAINT_RESPONSIBLE,
		CSMAGIC_EMBEDDED_LAUNCH_CONSTRAINT);
	if (launch_constraint_responsible) {
		new_blob_size += sizeof(CS_BlobIndex);
		new_blob_size += ntohl(launch_constraint_responsible->length);
		num_blobs += 1;
	}

	/* Conditional storage for the entitlements blob */
	entitlements_blob = blob->csb_entitlements_blob;
	if (entitlements_blob) {
		new_blob_size += sizeof(CS_BlobIndex);
		new_blob_size += ntohl(entitlements_blob->length);
		num_blobs += 1;
	}

	/* Conditional storage for the CMS blob */
	cms_blob = csblob_find_blob_bytes((const uint8_t *)blob->csb_mem_kaddr, blob->csb_mem_size, CSSLOT_SIGNATURESLOT, CSMAGIC_BLOBWRAPPER);
	if (cms_blob) {
		new_blob_size += sizeof(CS_BlobIndex);
		new_blob_size += ntohl(cms_blob->length);
		num_blobs += 1;
	}

	/*
	 * Conditional storage for the first code directory.
	 * This is only needed if a CMS blob exists and the best code directory isn't already
	 * the first one. It is an error if we find a CMS blob but do not find a first code directory.
	 */
	if (cms_blob) {
		first_code_directory = csblob_find_blob_bytes((const uint8_t *)blob->csb_mem_kaddr, blob->csb_mem_size, CSSLOT_CODEDIRECTORY, CSMAGIC_CODEDIRECTORY);
		if (first_code_directory == best_code_directory) {
			/* We don't need the first code directory anymore, since the best one is already it */
			first_code_directory = NULL;
		} else if (first_code_directory) {
			new_blob_size += sizeof(CS_BlobIndex);
			new_blob_size += ntohl(first_code_directory->length);
			num_blobs += 1;
		} else {
			printf("CODE SIGNING: Invalid CS Blob: found CMS blob but not a first code directory\n");
			return EINVAL;
		}
	}

	/*
	 * The blob size could be rouded up to page size here, so we keep a copy
	 * of the actual superblob length as well.
	 */
	vm_size_t new_blob_allocation_size = new_blob_size;
	ret = ubc_cs_blob_allocate(&new_blob_addr, &new_blob_allocation_size);
	if (ret != KERN_SUCCESS) {
		printf("CODE SIGNING: Failed to allocate memory for new code signing blob: %d\n", ret);
		return ENOMEM;
	}

	/*
	 * Fill out the superblob header and then all the blobs in the order listed
	 * above.
	 */
	superblob = (CS_SuperBlob*)new_blob_addr;
	superblob->magic = htonl(CSMAGIC_EMBEDDED_SIGNATURE);
	superblob->length = htonl((uint32_t)new_blob_size);
	superblob->count = htonl(num_blobs);

	blob_index = 0;
	blob_offset = sizeof(CS_SuperBlob) + (num_blobs * sizeof(CS_BlobIndex));

	/* Best code directory */
	superblob->index[blob_index].offset = htonl(blob_offset);
	if (first_code_directory) {
		superblob->index[blob_index].type = htonl(CSSLOT_ALTERNATE_CODEDIRECTORIES);
	} else {
		superblob->index[blob_index].type = htonl(CSSLOT_CODEDIRECTORY);
	}

	if (code_directory_size > 0) {
		/* We zero out the code directory, as we expect the caller to fill it in */
		memset((void*)(new_blob_addr + blob_offset), 0, new_code_directory_size);
	} else {
		memcpy((void*)(new_blob_addr + blob_offset), best_code_directory, new_code_directory_size);
	}

	if (code_directory) {
		*code_directory = (CS_CodeDirectory*)(new_blob_addr + blob_offset);
	}
	blob_offset += new_code_directory_size;

	/* DER entitlements blob */
	if (der_entitlements_blob) {
		blob_index += 1;
		superblob->index[blob_index].offset = htonl(blob_offset);
		superblob->index[blob_index].type = htonl(CSSLOT_DER_ENTITLEMENTS);

		memcpy((void*)(new_blob_addr + blob_offset), der_entitlements_blob, ntohl(der_entitlements_blob->length));
		blob_offset += ntohl(der_entitlements_blob->length);
	}

	/* Launch constraints self blob */
	if (launch_constraint_self) {
		blob_index += 1;
		superblob->index[blob_index].offset = htonl(blob_offset);
		superblob->index[blob_index].type = htonl(CSSLOT_LAUNCH_CONSTRAINT_SELF);

		memcpy(
			(void*)(new_blob_addr + blob_offset),
			launch_constraint_self,
			ntohl(launch_constraint_self->length));

		blob_offset += ntohl(launch_constraint_self->length);
	}

	/* Launch constraints parent blob */
	if (launch_constraint_parent) {
		blob_index += 1;
		superblob->index[blob_index].offset = htonl(blob_offset);
		superblob->index[blob_index].type = htonl(CSSLOT_LAUNCH_CONSTRAINT_PARENT);

		memcpy(
			(void*)(new_blob_addr + blob_offset),
			launch_constraint_parent,
			ntohl(launch_constraint_parent->length));

		blob_offset += ntohl(launch_constraint_parent->length);
	}

	/* Launch constraints responsible blob */
	if (launch_constraint_responsible) {
		blob_index += 1;
		superblob->index[blob_index].offset = htonl(blob_offset);
		superblob->index[blob_index].type = htonl(CSSLOT_LAUNCH_CONSTRAINT_RESPONSIBLE);

		memcpy(
			(void*)(new_blob_addr + blob_offset),
			launch_constraint_responsible,
			ntohl(launch_constraint_responsible->length));

		blob_offset += ntohl(launch_constraint_responsible->length);
	}

	/* Entitlements blob */
	if (entitlements_blob) {
		blob_index += 1;
		superblob->index[blob_index].offset = htonl(blob_offset);
		superblob->index[blob_index].type = htonl(CSSLOT_ENTITLEMENTS);

		memcpy((void*)(new_blob_addr + blob_offset), entitlements_blob, ntohl(entitlements_blob->length));
		blob_offset += ntohl(entitlements_blob->length);
	}

	/* CMS blob */
	if (cms_blob) {
		blob_index += 1;
		superblob->index[blob_index].offset = htonl(blob_offset);
		superblob->index[blob_index].type = htonl(CSSLOT_SIGNATURESLOT);
		memcpy((void*)(new_blob_addr + blob_offset), cms_blob, ntohl(cms_blob->length));
		blob_offset += ntohl(cms_blob->length);
	}

	/* First code directory */
	if (first_code_directory) {
		blob_index += 1;
		superblob->index[blob_index].offset = htonl(blob_offset);
		superblob->index[blob_index].type = htonl(CSSLOT_CODEDIRECTORY);
		memcpy((void*)(new_blob_addr + blob_offset), first_code_directory, ntohl(first_code_directory->length));
		blob_offset += ntohl(first_code_directory->length);
	}

	/*
	 * We only validate the blob in case we copied in the best code directory.
	 * In case the code directory size we were passed in wasn't 0, we memset the best
	 * code directory to 0 and expect the caller to fill it in. In the same spirit, we
	 * expect the caller to validate the code signature after they fill in the code
	 * directory.
	 */
	if (code_directory_size == 0) {
		const CS_CodeDirectory *validated_code_directory = NULL;
		const CS_GenericBlob *validated_entitlements_blob = NULL;
		const CS_GenericBlob *validated_der_entitlements_blob = NULL;

		ret = cs_validate_csblob(
			(const uint8_t *)superblob,
			new_blob_size,
			&validated_code_directory,
			&validated_entitlements_blob,
			&validated_der_entitlements_blob);

		if (ret) {
			printf("unable to validate reconstituted cs_blob: %d\n", ret);
			err = EINVAL;
			goto fail;
		}
	}

	if (ret_mem_kaddr) {
		*ret_mem_kaddr = new_blob_addr;
	}
	if (ret_mem_size) {
		*ret_mem_size = new_blob_allocation_size;
	}

	return 0;

fail:
	ubc_cs_blob_deallocate(new_blob_addr, new_blob_allocation_size);
	return err;
}

/*
 * We use this function to clear out unnecessary bits from the code signature
 * blob which are no longer needed. We free these bits and give them back to
 * the kernel. This is needed since reconstitution includes extra data which is
 * needed only for verification but has no point in keeping afterwards.
 *
 * This results in significant memory reduction, especially for 3rd party apps
 * since we also get rid of the CMS blob.
 */
static errno_t
ubc_cs_reconstitute_code_signature_2nd_stage(
	struct cs_blob *blob
	)
{
	kern_return_t ret = KERN_FAILURE;
	const CS_GenericBlob *launch_constraint_self = NULL;
	const CS_GenericBlob *launch_constraint_parent = NULL;
	const CS_GenericBlob *launch_constraint_responsible = NULL;
	CS_SuperBlob *superblob = NULL;
	uint32_t num_blobs = 0;
	vm_size_t last_needed_blob_offset = 0;
	vm_offset_t code_directory_offset = 0;

	/*
	 * Ordering of blobs we need to keep:
	 * 1. Code directory
	 * 2. DER encoded entitlements (if present)
	 * 3. Launch constraints self (if present)
	 * 3. Launch constraints parent (if present)
	 * 3. Launch constraints responsible (if present)
	 *
	 * We need to clear out the remaining page after these blobs end, and fix up
	 * the superblob for the changes. Things gets a little more complicated for
	 * blobs which may not have been kmem_allocated. For those, we simply just
	 * allocate the new required space and copy into it.
	 */

	if (blob == NULL) {
		printf("NULL blob passed in for 2nd stage reconstitution\n");
		return EINVAL;
	}
	assert(blob->csb_reconstituted == true);

	/* Ensure we're not page-wise allocated when in this function */
	assert(ubc_cs_blob_pagewise_allocate(blob->csb_mem_size) == false);

	if (!blob->csb_cd) {
		/* This case can never happen, and it is a sign of bad things */
		panic("validated cs_blob has no code directory");
	}
	superblob = (CS_SuperBlob*)blob->csb_mem_kaddr;

	num_blobs = 1;
	last_needed_blob_offset = ntohl(superblob->index[0].offset) + ntohl(blob->csb_cd->length);

	/* Check for DER entitlements */
	if (blob->csb_der_entitlements_blob) {
		num_blobs += 1;
		last_needed_blob_offset += ntohl(blob->csb_der_entitlements_blob->length);
	}

	/* Check for launch constraints self */
	launch_constraint_self = csblob_find_blob_bytes(
		(const uint8_t *)blob->csb_mem_kaddr,
		blob->csb_mem_size,
		CSSLOT_LAUNCH_CONSTRAINT_SELF,
		CSMAGIC_EMBEDDED_LAUNCH_CONSTRAINT);
	if (launch_constraint_self) {
		num_blobs += 1;
		last_needed_blob_offset += ntohl(launch_constraint_self->length);
	}

	/* Check for launch constraints parent */
	launch_constraint_parent = csblob_find_blob_bytes(
		(const uint8_t *)blob->csb_mem_kaddr,
		blob->csb_mem_size,
		CSSLOT_LAUNCH_CONSTRAINT_PARENT,
		CSMAGIC_EMBEDDED_LAUNCH_CONSTRAINT);
	if (launch_constraint_parent) {
		num_blobs += 1;
		last_needed_blob_offset += ntohl(launch_constraint_parent->length);
	}

	/* Check for launch constraints responsible */
	launch_constraint_responsible = csblob_find_blob_bytes(
		(const uint8_t *)blob->csb_mem_kaddr,
		blob->csb_mem_size,
		CSSLOT_LAUNCH_CONSTRAINT_RESPONSIBLE,
		CSMAGIC_EMBEDDED_LAUNCH_CONSTRAINT);
	if (launch_constraint_responsible) {
		num_blobs += 1;
		last_needed_blob_offset += ntohl(launch_constraint_responsible->length);
	}

	superblob->count = htonl(num_blobs);
	superblob->length = htonl((uint32_t)last_needed_blob_offset);

	/*
	 * There is a chance that the code directory is marked within the superblob as an
	 * alternate code directory. This happens when the first code directory isn't the
	 * best one chosen by the kernel, so to be able to access both the first and the best,
	 * we save the best one as an alternate one. Since we're getting rid of the first one
	 * here, we mark the best one as the first one.
	 */
	superblob->index[0].type = htonl(CSSLOT_CODEDIRECTORY);

	vm_address_t new_superblob = 0;
	vm_size_t new_superblob_size = last_needed_blob_offset;

	ret = ubc_cs_blob_allocate(&new_superblob, &new_superblob_size);
	if (ret != KERN_SUCCESS) {
		printf("unable to allocate memory for 2nd stage reconstitution: %d\n", ret);
		return ENOMEM;
	}
	assert(new_superblob_size == last_needed_blob_offset);

	/* Calculate the code directory offset */
	code_directory_offset = (vm_offset_t)blob->csb_cd - (vm_offset_t)blob->csb_mem_kaddr;

	/* Copy in the updated superblob into the new memory */
	memcpy((void*)new_superblob, superblob, new_superblob_size);

	/* Free the old code signature and old memory */
	ubc_cs_blob_deallocate((vm_offset_t)blob->csb_mem_kaddr, blob->csb_mem_size);

	/* Reconstruct critical fields in the blob object */
	ubc_cs_blob_reconstruct(
		blob,
		new_superblob,
		new_superblob_size,
		code_directory_offset);

	/* XML entitlements should've been removed */
	assert(blob->csb_entitlements_blob == NULL);

	const CS_CodeDirectory *validated_code_directory = NULL;
	const CS_GenericBlob *validated_entitlements_blob = NULL;
	const CS_GenericBlob *validated_der_entitlements_blob = NULL;

	ret = cs_validate_csblob(
		(const uint8_t*)blob->csb_mem_kaddr,
		blob->csb_mem_size,
		&validated_code_directory,
		&validated_entitlements_blob,
		&validated_der_entitlements_blob);
	if (ret) {
		printf("unable to validate code signature after 2nd stage reconstitution: %d\n", ret);
		return EINVAL;
	}

	return 0;
}

static int
ubc_cs_convert_to_multilevel_hash(struct cs_blob *blob)
{
	const CS_CodeDirectory  *old_cd, *cd;
	CS_CodeDirectory        *new_cd;
	const CS_GenericBlob *entitlements;
	const CS_GenericBlob *der_entitlements;
	vm_offset_t     new_blob_addr;
	vm_size_t       new_blob_size;
	vm_size_t       new_cdsize;
	int                             error;

	uint32_t                hashes_per_new_hash_shift = (uint32_t)(PAGE_SHIFT - blob->csb_hash_pageshift);

	if (cs_debug > 1) {
		printf("CODE SIGNING: Attempting to convert Code Directory for %lu -> %lu page shift\n",
		    (unsigned long)blob->csb_hash_pageshift, (unsigned long)PAGE_SHIFT);
	}

	old_cd = blob->csb_cd;

	/* Up to the hashes, we can copy all data */
	new_cdsize  = ntohl(old_cd->hashOffset);
	new_cdsize += (ntohl(old_cd->nCodeSlots) >> hashes_per_new_hash_shift) * old_cd->hashSize;

	error = ubc_cs_reconstitute_code_signature(blob, &new_blob_addr, &new_blob_size, new_cdsize, &new_cd);
	if (error != 0) {
		printf("CODE SIGNING: Failed to reconsitute code signature: %d\n", error);
		return error;
	}
	entitlements = csblob_find_blob_bytes((uint8_t*)new_blob_addr, new_blob_size, CSSLOT_ENTITLEMENTS, CSMAGIC_EMBEDDED_ENTITLEMENTS);
	der_entitlements = csblob_find_blob_bytes((uint8_t*)new_blob_addr, new_blob_size, CSSLOT_DER_ENTITLEMENTS, CSMAGIC_EMBEDDED_DER_ENTITLEMENTS);

	memcpy(new_cd, old_cd, ntohl(old_cd->hashOffset));

	/* Update fields in the Code Directory structure */
	new_cd->length = htonl((uint32_t)new_cdsize);

	uint32_t nCodeSlots = ntohl(new_cd->nCodeSlots);
	nCodeSlots >>= hashes_per_new_hash_shift;
	new_cd->nCodeSlots = htonl(nCodeSlots);

	new_cd->pageSize = (uint8_t)PAGE_SHIFT; /* Not byte-swapped */

	if ((ntohl(new_cd->version) >= CS_SUPPORTSSCATTER) && (ntohl(new_cd->scatterOffset))) {
		SC_Scatter *scatter = (SC_Scatter*)
		    ((char *)new_cd + ntohl(new_cd->scatterOffset));
		/* iterate all scatter structs to scale their counts */
		do {
			uint32_t scount = ntohl(scatter->count);
			uint32_t sbase  = ntohl(scatter->base);

			/* last scatter? */
			if (scount == 0) {
				break;
			}

			scount >>= hashes_per_new_hash_shift;
			scatter->count = htonl(scount);

			sbase >>= hashes_per_new_hash_shift;
			scatter->base = htonl(sbase);

			scatter++;
		} while (1);
	}

	/* For each group of hashes, hash them together */
	const unsigned char *src_base = (const unsigned char *)old_cd + ntohl(old_cd->hashOffset);
	unsigned char *dst_base = (unsigned char *)new_cd + ntohl(new_cd->hashOffset);

	uint32_t hash_index;
	for (hash_index = 0; hash_index < nCodeSlots; hash_index++) {
		union cs_hash_union     mdctx;

		uint32_t source_hash_len = old_cd->hashSize << hashes_per_new_hash_shift;
		const unsigned char *src = src_base + hash_index * source_hash_len;
		unsigned char *dst = dst_base + hash_index * new_cd->hashSize;

		blob->csb_hashtype->cs_init(&mdctx);
		blob->csb_hashtype->cs_update(&mdctx, src, source_hash_len);
		blob->csb_hashtype->cs_final(dst, &mdctx);
	}

	error = cs_validate_csblob((const uint8_t *)new_blob_addr, new_blob_size, &cd, &entitlements, &der_entitlements);
	if (error != 0) {
		printf("CODE SIGNING: Failed to validate new Code Signing Blob: %d\n",
		    error);

		ubc_cs_blob_deallocate(new_blob_addr, new_blob_size);
		return error;
	}

	/* New Code Directory is ready for use, swap it out in the blob structure */
	ubc_cs_blob_deallocate((vm_offset_t)blob->csb_mem_kaddr, blob->csb_mem_size);

	blob->csb_mem_size = new_blob_size;
	blob->csb_mem_kaddr = (void *)new_blob_addr;
	blob->csb_cd = cd;
	blob->csb_entitlements_blob = NULL;

	blob->csb_der_entitlements_blob = der_entitlements; /* may be NULL, not yet validated */
	blob->csb_reconstituted = true;

	/* The blob has some cached attributes of the Code Directory, so update those */

	blob->csb_hash_firstlevel_pageshift = blob->csb_hash_pageshift; /* Save the original page size */

	blob->csb_hash_pageshift = PAGE_SHIFT;
	blob->csb_end_offset = ntohl(cd->codeLimit);
	if ((ntohl(cd->version) >= CS_SUPPORTSSCATTER) && (ntohl(cd->scatterOffset))) {
		const SC_Scatter *scatter = (const SC_Scatter*)
		    ((const char*)cd + ntohl(cd->scatterOffset));
		blob->csb_start_offset = ((off_t)ntohl(scatter->base)) * PAGE_SIZE;
	} else {
		blob->csb_start_offset = 0;
	}

	return 0;
}

static void
cs_blob_cleanup(struct cs_blob *blob)
{
	if (blob->csb_entitlements != NULL) {
		amfi->OSEntitlements_invalidate(blob->csb_entitlements);
		osobject_release(blob->csb_entitlements);
		blob->csb_entitlements = NULL;
	}

#if CODE_SIGNING_MONITOR
	if (blob->csb_csm_obj != NULL) {
		/* Unconditionally remove any profiles we may have associated */
		csm_disassociate_provisioning_profile(blob->csb_csm_obj);

		kern_return_t kr = csm_unregister_code_signature(blob->csb_csm_obj);
		if (kr == KERN_SUCCESS) {
			/*
			 * If the code signature was monitor managed, the monitor will have freed it
			 * itself in the unregistration call. It means we do not need to free the data
			 * over here.
			 */
			if (blob->csb_csm_managed) {
				blob->csb_mem_kaddr = NULL;
				blob->csb_mem_size = 0;
			}
		}
	}

	/* Unconditionally remove references to the monitor */
	blob->csb_csm_obj = NULL;
	blob->csb_csm_managed = false;
#endif

	if (blob->csb_mem_kaddr) {
		ubc_cs_blob_deallocate((vm_offset_t)blob->csb_mem_kaddr, blob->csb_mem_size);
	}
	blob->csb_mem_kaddr = NULL;
	blob->csb_mem_size = 0;
}

static void
cs_blob_ro_free(struct cs_blob *blob)
{
	struct cs_blob tmp;

	if (blob != NULL) {
		/*
		 * cs_blob_cleanup clears fields, so we need to pass it a
		 * mutable copy.
		 */
		tmp = *blob;
		cs_blob_cleanup(&tmp);

		zfree_ro(ZONE_ID_CS_BLOB, blob);
	}
}

/*
 * Free a cs_blob previously created by cs_blob_create_validated.
 */
void
cs_blob_free(
	struct cs_blob *blob)
{
	cs_blob_ro_free(blob);
}

static int
cs_blob_init_validated(
	vm_address_t * const addr,
	vm_size_t size,
	struct cs_blob *blob,
	CS_CodeDirectory const ** const ret_cd)
{
	int error = EINVAL;
	const CS_CodeDirectory *cd = NULL;
	const CS_GenericBlob *entitlements = NULL;
	const CS_GenericBlob *der_entitlements = NULL;
	union cs_hash_union mdctx;
	size_t length;

	bzero(blob, sizeof(*blob));

	/* fill in the new blob */
	blob->csb_mem_size = size;
	blob->csb_mem_offset = 0;
	blob->csb_mem_kaddr = (void *)*addr;
	blob->csb_flags = 0;
	blob->csb_signer_type = CS_SIGNER_TYPE_UNKNOWN;
	blob->csb_platform_binary = 0;
	blob->csb_platform_path = 0;
	blob->csb_teamid = NULL;
#if CONFIG_SUPPLEMENTAL_SIGNATURES
	blob->csb_supplement_teamid = NULL;
#endif
	blob->csb_entitlements_blob = NULL;
	blob->csb_der_entitlements_blob = NULL;
	blob->csb_entitlements = NULL;
#if CODE_SIGNING_MONITOR
	blob->csb_csm_obj = NULL;
	blob->csb_csm_managed = false;
#endif
	blob->csb_reconstituted = false;
	blob->csb_validation_category = CS_VALIDATION_CATEGORY_INVALID;

	/* Transfer ownership. Even on error, this function will deallocate */
	*addr = 0;

	/*
	 * Validate the blob's contents
	 */
	length = (size_t) size;
	error = cs_validate_csblob((const uint8_t *)blob->csb_mem_kaddr,
	    length, &cd, &entitlements, &der_entitlements);
	if (error) {
		if (cs_debug) {
			printf("CODESIGNING: csblob invalid: %d\n", error);
		}
		/*
		 * The vnode checker can't make the rest of this function
		 * succeed if csblob validation failed, so bail */
		goto out;
	} else {
		const unsigned char *md_base;
		uint8_t hash[CS_HASH_MAX_SIZE];
		int md_size;
		vm_offset_t hash_pagemask;

		blob->csb_cd = cd;
		blob->csb_entitlements_blob = entitlements; /* may be NULL, not yet validated */
		blob->csb_der_entitlements_blob = der_entitlements; /* may be NULL, not yet validated */
		blob->csb_hashtype = cs_find_md(cd->hashType);
		if (blob->csb_hashtype == NULL || blob->csb_hashtype->cs_digest_size > sizeof(hash)) {
			panic("validated CodeDirectory but unsupported type");
		}

		blob->csb_hash_pageshift = cd->pageSize;
		hash_pagemask = (1U << cd->pageSize) - 1;
		blob->csb_hash_firstlevel_pageshift = 0;
		blob->csb_flags = (ntohl(cd->flags) & CS_ALLOWED_MACHO) | CS_VALID;
		blob->csb_end_offset = (((vm_offset_t)ntohl(cd->codeLimit) + hash_pagemask) & ~hash_pagemask);
		if ((ntohl(cd->version) >= CS_SUPPORTSSCATTER) && (ntohl(cd->scatterOffset))) {
			const SC_Scatter *scatter = (const SC_Scatter*)
			    ((const char*)cd + ntohl(cd->scatterOffset));
			blob->csb_start_offset = ((off_t)ntohl(scatter->base)) * (1U << blob->csb_hash_pageshift);
		} else {
			blob->csb_start_offset = 0;
		}
		/* compute the blob's cdhash */
		md_base = (const unsigned char *) cd;
		md_size = ntohl(cd->length);

		blob->csb_hashtype->cs_init(&mdctx);
		blob->csb_hashtype->cs_update(&mdctx, md_base, md_size);
		blob->csb_hashtype->cs_final(hash, &mdctx);

		memcpy(blob->csb_cdhash, hash, CS_CDHASH_LEN);

#if CONFIG_SUPPLEMENTAL_SIGNATURES
		blob->csb_linkage_hashtype = NULL;
		if (ntohl(cd->version) >= CS_SUPPORTSLINKAGE && cd->linkageHashType != 0 &&
		    ntohl(cd->linkageSize) >= CS_CDHASH_LEN) {
			blob->csb_linkage_hashtype = cs_find_md(cd->linkageHashType);

			if (blob->csb_linkage_hashtype != NULL) {
				memcpy(blob->csb_linkage, (uint8_t const*)cd + ntohl(cd->linkageOffset),
				    CS_CDHASH_LEN);
			}
		}
#endif
	}

	error = 0;

out:
	if (error != 0) {
		cs_blob_cleanup(blob);
		blob = NULL;
		cd = NULL;
	}

	if (ret_cd != NULL) {
		*ret_cd = cd;
	}

	return error;
}

/*
 * Validate the code signature blob, create a struct cs_blob wrapper
 * and return it together with a pointer to the chosen code directory
 * and entitlements blob.
 *
 * Note that this takes ownership of the memory as addr, mainly because
 * this function can actually replace the passed in blob with another
 * one, e.g. when performing multilevel hashing optimization.
 */
int
cs_blob_create_validated(
	vm_address_t * const            addr,
	vm_size_t                       size,
	struct cs_blob ** const         ret_blob,
	CS_CodeDirectory const ** const     ret_cd)
{
	struct cs_blob blob = {};
	struct cs_blob *ro_blob;
	int error;

	if (ret_blob) {
		*ret_blob = NULL;
	}

	if ((error = cs_blob_init_validated(addr, size, &blob, ret_cd)) != 0) {
		return error;
	}

	if (ret_blob != NULL) {
		ro_blob = zalloc_ro(ZONE_ID_CS_BLOB, Z_WAITOK | Z_NOFAIL);
		zalloc_ro_update_elem(ZONE_ID_CS_BLOB, ro_blob, &blob);
		*ret_blob = ro_blob;
	}

	return error;
}

#if CONFIG_SUPPLEMENTAL_SIGNATURES
static void
cs_blob_supplement_free(struct cs_blob * const blob)
{
	void *teamid;

	if (blob != NULL) {
		if (blob->csb_supplement_teamid != NULL) {
			teamid = blob->csb_supplement_teamid;
			vm_size_t teamid_size = strlen(blob->csb_supplement_teamid) + 1;
			kfree_data(teamid, teamid_size);
		}
		cs_blob_ro_free(blob);
	}
}
#endif

static void
ubc_cs_blob_adjust_statistics(struct cs_blob const *blob)
{
	/* Note that the atomic ops are not enough to guarantee
	 * correctness: If a blob with an intermediate size is inserted
	 * concurrently, we can lose a peak value assignment. But these
	 * statistics are only advisory anyway, so we're not going to
	 * employ full locking here. (Consequently, we are also okay with
	 * relaxed ordering of those accesses.)
	 */

	unsigned int new_cs_blob_count = os_atomic_add(&cs_blob_count, 1, relaxed);
	if (new_cs_blob_count > os_atomic_load(&cs_blob_count_peak, relaxed)) {
		os_atomic_store(&cs_blob_count_peak, new_cs_blob_count, relaxed);
	}

	size_t new_cs_blob_size = os_atomic_add(&cs_blob_size, blob->csb_mem_size, relaxed);

	if (new_cs_blob_size > os_atomic_load(&cs_blob_size_peak, relaxed)) {
		os_atomic_store(&cs_blob_size_peak, new_cs_blob_size, relaxed);
	}
	if (blob->csb_mem_size > os_atomic_load(&cs_blob_size_max, relaxed)) {
		os_atomic_store(&cs_blob_size_max, blob->csb_mem_size, relaxed);
	}
}

static void
cs_blob_set_cpu_type(struct cs_blob *blob, cpu_type_t cputype)
{
	zalloc_ro_update_field(ZONE_ID_CS_BLOB, blob, csb_cpu_type, &cputype);
}

__abortlike
static void
panic_cs_blob_backref_mismatch(struct cs_blob *blob, struct vnode *vp)
{
	panic("cs_blob vnode backref mismatch: blob=%p, vp=%p, "
	    "blob->csb_vnode=%p", blob, vp, blob->csb_vnode);
}

void
cs_blob_require(struct cs_blob *blob, vnode_t vp)
{
	zone_require_ro(ZONE_ID_CS_BLOB, sizeof(struct cs_blob), blob);

	if (vp != NULL && __improbable(blob->csb_vnode != vp)) {
		panic_cs_blob_backref_mismatch(blob, vp);
	}
}

#if CODE_SIGNING_MONITOR

/**
 * Independently verify the authenticity of the code signature through the monitor
 * environment. This is required as otherwise the monitor won't allow associations
 * of the code signature with address spaces.
 *
 * Once we've verified the code signature, we no longer need to keep around any
 * provisioning profiles we may have registered with it. AMFI associates profiles
 * with the monitor during its validation (which happens before the monitor's).
 */
static errno_t
verify_code_signature_monitor(
	struct cs_blob *cs_blob)
{
	kern_return_t ret = KERN_DENIED;

	ret = csm_verify_code_signature(cs_blob->csb_csm_obj);
	if ((ret != KERN_SUCCESS) && (ret != KERN_NOT_SUPPORTED)) {
		printf("unable to verify code signature with monitor: %d\n", ret);
		return EPERM;
	}

	ret = csm_disassociate_provisioning_profile(cs_blob->csb_csm_obj);
	if ((ret != KERN_SUCCESS) && (ret != KERN_NOT_FOUND) && (ret != KERN_NOT_SUPPORTED)) {
		printf("unable to disassociate profile from code signature: %d\n", ret);
		return EPERM;
	}

	/* Associate the OSEntitlements kernel object with the monitor */
	ret = csm_associate_os_entitlements(cs_blob->csb_csm_obj, cs_blob->csb_entitlements);
	if ((ret != KERN_SUCCESS) && (ret != KERN_NOT_SUPPORTED)) {
		printf("unable to associate OSEntitlements with monitor: %d\n", ret);
		return EPERM;
	}

	return 0;
}

/**
 * Register the code signature with the code signing monitor environment. This
 * will effectively make the blob data immutable, either because the blob memory
 * will be allocated and managed directory by the monitor, or because the monitor
 * will lockdown the memory associated with the blob.
 */
static errno_t
register_code_signature_monitor(
	struct vnode *vnode,
	struct cs_blob *cs_blob,
	vm_offset_t code_directory_offset)
{
	kern_return_t ret = KERN_DENIED;
	vm_address_t monitor_signature_addr = 0;
	void *monitor_sig_object = NULL;
	const char *vnode_path_ptr = NULL;

	/*
	 * Attempt to resolve the path for this vnode and pass it in to the code
	 * signing monitor during registration.
	 */
	int vnode_path_len = MAXPATHLEN;
	char *vnode_path = kalloc_data(vnode_path_len, Z_WAITOK);

	errno_t error = vnode_getwithref(vnode);
	if (error == 0) {
		error = vn_getpath(vnode, vnode_path, &vnode_path_len);
		if (error == 0) {
			vnode_path_ptr = vnode_path;
		}

		/* Release reference count on the vnode */
		(void)vnode_put(vnode);
	}

	ret = csm_register_code_signature(
		(vm_address_t)cs_blob->csb_mem_kaddr,
		cs_blob->csb_mem_size,
		code_directory_offset,
		vnode_path_ptr,
		&monitor_sig_object,
		&monitor_signature_addr);

	kfree_data(vnode_path, MAXPATHLEN);
	vnode_path_ptr = NULL;

	if (ret == KERN_SUCCESS) {
		/* Reconstruct the cs_blob if the monitor used its own allocation */
		if (monitor_signature_addr != (vm_address_t)cs_blob->csb_mem_kaddr) {
			vm_address_t monitor_signature_size = cs_blob->csb_mem_size;

			/* Free the old memory for the blob */
			ubc_cs_blob_deallocate(
				(vm_address_t)cs_blob->csb_mem_kaddr,
				cs_blob->csb_mem_size);

			/* Reconstruct critical fields in the blob object */
			ubc_cs_blob_reconstruct(
				cs_blob,
				monitor_signature_addr,
				monitor_signature_size,
				code_directory_offset);

			/* Mark the signature as monitor managed */
			cs_blob->csb_csm_managed = true;
		}
	} else if (ret != KERN_NOT_SUPPORTED) {
		printf("unable to register code signature with monitor: %d\n", ret);
		return EPERM;
	}

	/* Save the monitor handle for the signature object -- may be NULL */
	cs_blob->csb_csm_obj = monitor_sig_object;

	return 0;
}

#endif /* CODE_SIGNING_MONITOR */

/**
 * Accelerate entitlements for a code signature object. When we have a code
 * signing monitor, this acceleration is done within the monitor which then
 * passes back a CoreEntitlements query context the kernel can use. When we
 * don't have a code signing monitor, we accelerate the queries within the
 * kernel memory itself.
 *
 * This function must be called when the storage for the code signature can
 * no longer change.
 */
static errno_t
accelerate_entitlement_queries(
	struct cs_blob *cs_blob)
{
	kern_return_t ret = KERN_NOT_SUPPORTED;

#if CODE_SIGNING_MONITOR
	CEQueryContext_t ce_ctx = NULL;
	const char *signing_id = NULL;

	ret = csm_accelerate_entitlements(cs_blob->csb_csm_obj, &ce_ctx);
	if ((ret != KERN_SUCCESS) && (ret != KERN_NOT_SUPPORTED)) {
		printf("unable to accelerate entitlements through the monitor: %d\n", ret);
		return EPERM;
	}

	if (ret == KERN_SUCCESS) {
		/* Call cannot not fail at this stage */
		ret = csm_acquire_signing_identifier(cs_blob->csb_csm_obj, &signing_id);
		assert(ret == KERN_SUCCESS);

		/* Adjust the OSEntitlements context with AMFI */
		ret = amfi->OSEntitlements.adjustContextWithMonitor(
			cs_blob->csb_entitlements,
			ce_ctx,
			cs_blob->csb_csm_obj,
			signing_id,
			cs_blob->csb_flags);
		if (ret != KERN_SUCCESS) {
			printf("unable to adjust OSEntitlements context with monitor: %d\n", ret);
			return EPERM;
		}

		return 0;
	}
#endif

	/*
	 * If we reach here, then either we don't have a code signing monitor, or
	 * the code signing monitor isn't enabled for code signing, in which case,
	 * AMFI is going to accelerate the entitlements context and adjust its
	 * context on its own.
	 */
	assert(ret == KERN_NOT_SUPPORTED);

	ret = amfi->OSEntitlements.adjustContextWithoutMonitor(
		cs_blob->csb_entitlements,
		cs_blob);

	if (ret != KERN_SUCCESS) {
		printf("unable to adjust OSEntitlements context without monitor: %d\n", ret);
		return EPERM;
	}

	return 0;
}

/**
 * Ensure and validate that some security critical code signing blobs haven't
 * been stripped off from the code signature. This can happen if an attacker
 * chose to load a code signature sans these critical blobs, or if there is a
 * bug in reconstitution logic which remove these blobs from the code signature.
 */
static errno_t
validate_auxiliary_signed_blobs(
	struct cs_blob *cs_blob)
{
	struct cs_blob_identifier {
		uint32_t cs_slot;
		uint32_t cs_magic;
	};

	const struct cs_blob_identifier identifiers[] = {
		{CSSLOT_LAUNCH_CONSTRAINT_SELF, CSMAGIC_EMBEDDED_LAUNCH_CONSTRAINT},
		{CSSLOT_LAUNCH_CONSTRAINT_PARENT, CSMAGIC_EMBEDDED_LAUNCH_CONSTRAINT},
		{CSSLOT_LAUNCH_CONSTRAINT_RESPONSIBLE, CSMAGIC_EMBEDDED_LAUNCH_CONSTRAINT}
	};
	const uint32_t num_identifiers = sizeof(identifiers) / sizeof(identifiers[0]);

	for (uint32_t i = 0; i < num_identifiers; i++) {
		errno_t err = csblob_find_special_slot_blob(
			cs_blob,
			identifiers[i].cs_slot,
			identifiers[i].cs_magic,
			NULL,
			NULL);

		if (err != 0) {
			printf("unable to validate security-critical blob: %d [%u|%u]\n",
			    err, identifiers[i].cs_slot, identifiers[i].cs_magic);

			return EPERM;
		}
	}

	return 0;
}

/**
 * Setup multi-level hashing for the code signature. This isn't supported on most
 * shipping devices, but on ones where it is, it can result in significant savings
 * of memory from the code signature standpoint.
 *
 * Multi-level hashing is used to condense the code directory hashes in order to
 * improve memory consumption. We take four 4K page hashes, and condense them into
 * a single 16K hash, hence reducing the space consumed by the code directory by
 * about ~75%.
 */
static errno_t
setup_multilevel_hashing(
	struct cs_blob *cs_blob)
{
	code_signing_monitor_type_t monitor_type = CS_MONITOR_TYPE_NONE;
	errno_t err = -1;

	/*
	 * When we have a code signing monitor, we do not support multi-level hashing
	 * since the code signature data is expected to be locked within memory which
	 * cannot be written to by the kernel.
	 *
	 * Even when the code signing monitor isn't explicitly enabled, there are other
	 * reasons for not performing multi-level hashing. For instance, Rosetta creates
	 * issues with multi-level hashing on Apple Silicon Macs.
	 */
	code_signing_configuration(&monitor_type, NULL);
	if (monitor_type != CS_MONITOR_TYPE_NONE) {
		return 0;
	}

	/* We need to check if multi-level hashing is supported for this blob */
	if (ubc_cs_supports_multilevel_hash(cs_blob) == false) {
		return 0;
	}

	err = ubc_cs_convert_to_multilevel_hash(cs_blob);
	if (err != 0) {
		printf("unable to setup multi-level hashing: %d\n", err);
		return err;
	}

	assert(cs_blob->csb_reconstituted == true);
	return 0;
}

/**
 * Once code signature validation is complete, we can remove even more blobs from the
 * code signature as they are no longer needed. This goes on to conserve even more
 * system memory.
 */
static errno_t
reconstitute_code_signature_2nd_stage(
	struct cs_blob *cs_blob)
{
	kern_return_t ret = KERN_NOT_SUPPORTED;
	errno_t err = EPERM;

	/* If we never reconstituted before, we won't be reconstituting again */
	if (cs_blob->csb_reconstituted == false) {
		return 0;
	}

#if CODE_SIGNING_MONITOR
	/*
	 * When we have a code signing monitor, the code signature is immutable until the
	 * monitor decides to unlock parts of it. Therefore, 2nd stage reconstitution takes
	 * place in the monitor when we have a monitor available.
	 *
	 * If the monitor isn't enforcing code signing (in which case the code signature is
	 * NOT immutable), then we perform 2nd stage reconstitution within the kernel itself.
	 */
	vm_address_t unneeded_addr = 0;
	vm_size_t unneeded_size = 0;

	ret = csm_reconstitute_code_signature(
		cs_blob->csb_csm_obj,
		&unneeded_addr,
		&unneeded_size);

	if ((ret == KERN_SUCCESS) && unneeded_addr && unneeded_size) {
		/* Free the unneded part of the blob */
		kmem_free(kernel_map, unneeded_addr, unneeded_size);

		/* Adjust the size in the blob object */
		cs_blob->csb_mem_size -= unneeded_size;
	}
#endif

	if (ret == KERN_SUCCESS) {
		goto success;
	} else if (ret != KERN_NOT_SUPPORTED) {
		/*
		 * A monitor environment is available, and it failed in performing 2nd stage
		 * reconstitution. This is a fatal issue for code signing validation.
		 */
		printf("unable to reconstitute code signature through monitor: %d\n", ret);
		return EPERM;
	}

	/* No monitor available if we reached here */
	err = ubc_cs_reconstitute_code_signature_2nd_stage(cs_blob);
	if (err != 0) {
		return err;
	}

success:
	/*
	 * Regardless of whether we are performing 2nd stage reconstitution in the monitor
	 * or in the kernel, we remove references to XML entitlements from the blob here.
	 * None of the 2nd stage reconstitution code ever keeps these around, and they have
	 * been explicitly deprecated and disallowed.
	 */
	cs_blob->csb_entitlements_blob = NULL;

	return 0;
}

/**
 * A code signature blob often contains blob which aren't needed in the kernel. Since
 * the code signature is wired into kernel memory for the time it is used, it behooves
 * us to remove any blobs we have no need for in order to conserve memory.
 *
 * Some platforms support copying the entire SuperBlob stored in kernel memory into
 * userspace memory through the "csops" system call. There is an expectation that when
 * this happens, all the blobs which were a part of the code signature are copied in
 * to userspace memory. As a result, these platforms cannot reconstitute the code
 * signature since, or rather, these platforms cannot remove blobs from the signature,
 * thereby making reconstitution useless.
 */
static errno_t
reconstitute_code_signature(
	struct cs_blob *cs_blob)
{
	CS_CodeDirectory *code_directory = NULL;
	vm_address_t signature_addr = 0;
	vm_size_t signature_size = 0;
	vm_offset_t code_directory_offset = 0;
	bool platform_supports_reconstitution = false;

#if CONFIG_CODE_SIGNATURE_RECONSTITUTION
	platform_supports_reconstitution = true;
#endif

	/*
	 * We can skip reconstitution if the code signing monitor isn't available or not
	 * enabled. But if we do have a monitor, then reconsitution becomes required, as
	 * there is an expectation of performing 2nd stage reconstitution through the
	 * monitor itself.
	 */
	if (platform_supports_reconstitution == false) {
#if CODE_SIGNING_MONITOR
		if (csm_enabled() == true) {
			printf("reconstitution required when code signing monitor is enabled\n");
			return EPERM;
		}
#endif
		return 0;
	}

	errno_t err = ubc_cs_reconstitute_code_signature(
		cs_blob,
		&signature_addr,
		&signature_size,
		0,
		&code_directory);

	if (err != 0) {
		printf("unable to reconstitute code signature: %d\n", err);
		return err;
	}

	/* Calculate the code directory offset */
	code_directory_offset = (vm_offset_t)code_directory - signature_addr;

	/* Reconstitution allocates new memory -- free the old one */
	ubc_cs_blob_deallocate((vm_address_t)cs_blob->csb_mem_kaddr, cs_blob->csb_mem_size);

	/* Reconstruct critical fields in the blob object */
	ubc_cs_blob_reconstruct(
		cs_blob,
		signature_addr,
		signature_size,
		code_directory_offset);

	/* Mark the object as reconstituted */
	cs_blob->csb_reconstituted = true;

	return 0;
}

int
ubc_cs_blob_add(
	struct vnode    *vp,
	uint32_t        platform,
	cpu_type_t      cputype,
	cpu_subtype_t   cpusubtype,
	off_t           base_offset,
	vm_address_t    *addr,
	vm_size_t       size,
	struct image_params *imgp,
	__unused int    flags,
	struct cs_blob  **ret_blob)
{
	ptrauth_generic_signature_t cs_blob_sig = {0};
	struct ubc_info *uip = NULL;
	struct cs_blob tmp_blob = {0};
	struct cs_blob *blob_ro = NULL;
	struct cs_blob *oblob = NULL;
	CS_CodeDirectory const *cd = NULL;
	off_t blob_start_offset = 0;
	off_t blob_end_offset = 0;
	boolean_t record_mtime = false;
	kern_return_t kr = KERN_DENIED;
	errno_t error = -1;

#if HAS_APPLE_PAC
	void *signed_entitlements = NULL;
#if CODE_SIGNING_MONITOR
	void *signed_monitor_obj = NULL;
#endif
#endif

	if (ret_blob) {
		*ret_blob = NULL;
	}

	/*
	 * Create the struct cs_blob abstract data type which will get attached to
	 * the vnode object. This function also validates the structural integrity
	 * of the code signature blob being passed in.
	 *
	 * We initialize a temporary blob whose contents are then copied into an RO
	 * blob which we allocate from the read-only allocator.
	 */
	error = cs_blob_init_validated(addr, size, &tmp_blob, &cd);
	if (error != 0) {
		printf("unable to create a validated cs_blob object: %d\n", error);
		return error;
	}

	tmp_blob.csb_cpu_type = cputype;
	tmp_blob.csb_cpu_subtype = cpusubtype & ~CPU_SUBTYPE_MASK;
	tmp_blob.csb_base_offset = base_offset;

	/* Perform 1st stage reconstitution */
	error = reconstitute_code_signature(&tmp_blob);
	if (error != 0) {
		goto out;
	}

	/*
	 * There is a strong design pattern we have to follow carefully within this
	 * function. Since we're storing the struct cs_blob within RO-allocated
	 * memory, it is immutable to modifications from within the kernel itself.
	 *
	 * However, before the contents of the blob are transferred to the immutable
	 * cs_blob, they are kept on the stack. In order to protect against a kernel
	 * R/W attacker, we must protect this stack variable. Most importantly, any
	 * code paths which can block for a while must compute a PAC signature over
	 * the stack variable, then perform the blocking operation, and then ensure
	 * that the PAC signature over the stack variable is still valid to ensure
	 * that an attacker did not overwrite contents of the blob by introducing a
	 * maliciously long blocking operation, giving them the time required to go
	 * and overwrite the contents of the blob.
	 *
	 * The most important fields to protect here are the OSEntitlements and the
	 * code signing monitor object references. For these ones, we keep around
	 * extra signed pointers diversified against the read-only blobs' memory
	 * and then update the stack variable with these before updating the full
	 * read-only blob.
	 */

	blob_ro = zalloc_ro(ZONE_ID_CS_BLOB, Z_WAITOK | Z_NOFAIL);
	assert(blob_ro != NULL);

	tmp_blob.csb_ro_addr = blob_ro;
	tmp_blob.csb_vnode = vp;

	/* AMFI needs to see the current blob state at the RO address */
	zalloc_ro_update_elem(ZONE_ID_CS_BLOB, blob_ro, &tmp_blob);

#if CODE_SIGNING_MONITOR
	error = register_code_signature_monitor(
		vp,
		&tmp_blob,
		(vm_offset_t)tmp_blob.csb_cd - (vm_offset_t)tmp_blob.csb_mem_kaddr);

	if (error != 0) {
		goto out;
	}

#if HAS_APPLE_PAC
	signed_monitor_obj = ptrauth_sign_unauthenticated(
		tmp_blob.csb_csm_obj,
		ptrauth_key_process_independent_data,
		ptrauth_blend_discriminator(&blob_ro->csb_csm_obj,
		OS_PTRAUTH_DISCRIMINATOR("cs_blob.csb_csm_obj")));
#endif /* HAS_APPLE_PAC */

#endif /* CODE_SIGNING_MONITOR */

#if CONFIG_MACF
	unsigned int cs_flags = tmp_blob.csb_flags;
	unsigned int signer_type = tmp_blob.csb_signer_type;

	error = mac_vnode_check_signature(
		vp,
		&tmp_blob,
		imgp,
		&cs_flags,
		&signer_type,
		flags,
		platform);

	if (error != 0) {
		printf("validation of code signature failed through MACF policy: %d\n", error);
		goto out;
	}

#if HAS_APPLE_PAC
	signed_entitlements = ptrauth_sign_unauthenticated(
		tmp_blob.csb_entitlements,
		ptrauth_key_process_independent_data,
		ptrauth_blend_discriminator(&blob_ro->csb_entitlements,
		OS_PTRAUTH_DISCRIMINATOR("cs_blob.csb_entitlements")));
#endif

	tmp_blob.csb_flags = cs_flags;
	tmp_blob.csb_signer_type = signer_type;

	if (tmp_blob.csb_flags & CS_PLATFORM_BINARY) {
		tmp_blob.csb_platform_binary = 1;
		tmp_blob.csb_platform_path = !!(tmp_blob.csb_flags & CS_PLATFORM_PATH);
		tmp_blob.csb_teamid = NULL;
	} else {
		tmp_blob.csb_platform_binary = 0;
		tmp_blob.csb_platform_path = 0;
	}

	if ((flags & MAC_VNODE_CHECK_DYLD_SIM) && !tmp_blob.csb_platform_binary) {
		printf("dyld simulator runtime is not apple signed: proc: %d\n",
		    proc_getpid(current_proc()));

		error = EPERM;
		goto out;
	}
#endif /* CONFIG_MACF */

#if CODE_SIGNING_MONITOR
	error = verify_code_signature_monitor(&tmp_blob);
	if (error != 0) {
		goto out;
	}
#endif

	/* Perform 2nd stage reconstitution */
	error = reconstitute_code_signature_2nd_stage(&tmp_blob);
	if (error != 0) {
		goto out;
	}

	/* Setup any multi-level hashing for the code signature */
	error = setup_multilevel_hashing(&tmp_blob);
	if (error != 0) {
		goto out;
	}

	/* Ensure security critical auxiliary blobs still exist */
	error = validate_auxiliary_signed_blobs(&tmp_blob);
	if (error != 0) {
		goto out;
	}

	/*
	 * Accelerate the entitlement queries for this code signature. This must
	 * be done only after we know that the code signature pointers within the
	 * struct cs_blob aren't going to be shifted around anymore, which is why
	 * this acceleration is done after setting up multilevel hashing, since
	 * that is the last part of signature validation which can shift the code
	 * signature around.
	 */
	error = accelerate_entitlement_queries(&tmp_blob);
	if (error != 0) {
		goto out;
	}

	/*
	 * Parse and set the Team ID for this code signature. This only needs to
	 * happen when the signature isn't marked as platform. Like above, this
	 * has to happen after we know the pointers within struct cs_blob aren't
	 * going to be shifted anymore.
	 */
	if ((tmp_blob.csb_flags & CS_PLATFORM_BINARY) == 0) {
		tmp_blob.csb_teamid = csblob_parse_teamid(&tmp_blob);
	}

	/*
	 * Validate the code signing blob's coverage. Ideally, we can just do this
	 * in the beginning, right after structural validation, however, multilevel
	 * hashing can change some offets.
	 */
	blob_start_offset = tmp_blob.csb_base_offset + tmp_blob.csb_start_offset;
	blob_end_offset = tmp_blob.csb_base_offset + tmp_blob.csb_end_offset;
	if (blob_start_offset >= blob_end_offset) {
		error = EINVAL;
		goto out;
	} else if (blob_start_offset < 0 || blob_end_offset <= 0) {
		error = EINVAL;
		goto out;
	}

	/*
	 * The vnode_lock, linked list traversal, and marking of the memory object as
	 * signed can all be blocking operations. Compute a PAC over the tmp_blob.
	 */
	cs_blob_sig = ptrauth_utils_sign_blob_generic(
		&tmp_blob,
		sizeof(tmp_blob),
		OS_PTRAUTH_DISCRIMINATOR("ubc_cs_blob_add.blocking_op0"),
		PTRAUTH_ADDR_DIVERSIFY);

	vnode_lock(vp);
	if (!UBCINFOEXISTS(vp)) {
		vnode_unlock(vp);
		error = ENOENT;
		goto out;
	}
	uip = vp->v_ubcinfo;

	/* check if this new blob overlaps with an existing blob */
	for (oblob = ubc_get_cs_blobs(vp);
	    oblob != NULL;
	    oblob = oblob->csb_next) {
		off_t oblob_start_offset, oblob_end_offset;

		if (tmp_blob.csb_signer_type != oblob->csb_signer_type) {  // signer type needs to be the same for slices
			vnode_unlock(vp);
			error = EALREADY;
			goto out;
		} else if (tmp_blob.csb_platform_binary) {  //platform binary needs to be the same for app slices
			if (!oblob->csb_platform_binary) {
				vnode_unlock(vp);
				error = EALREADY;
				goto out;
			}
		} else if (tmp_blob.csb_teamid) {  //teamid binary needs to be the same for app slices
			if (oblob->csb_platform_binary ||
			    oblob->csb_teamid == NULL ||
			    strcmp(oblob->csb_teamid, tmp_blob.csb_teamid) != 0) {
				vnode_unlock(vp);
				error = EALREADY;
				goto out;
			}
		} else {  // non teamid binary needs to be the same for app slices
			if (oblob->csb_platform_binary ||
			    oblob->csb_teamid != NULL) {
				vnode_unlock(vp);
				error = EALREADY;
				goto out;
			}
		}

		oblob_start_offset = (oblob->csb_base_offset +
		    oblob->csb_start_offset);
		oblob_end_offset = (oblob->csb_base_offset +
		    oblob->csb_end_offset);
		if (blob_start_offset >= oblob_end_offset ||
		    blob_end_offset <= oblob_start_offset) {
			/* no conflict with this existing blob */
		} else {
			/* conflict ! */
			if (blob_start_offset == oblob_start_offset &&
			    blob_end_offset == oblob_end_offset &&
			    tmp_blob.csb_mem_size == oblob->csb_mem_size &&
			    tmp_blob.csb_flags == oblob->csb_flags &&
			    (tmp_blob.csb_cpu_type == CPU_TYPE_ANY ||
			    oblob->csb_cpu_type == CPU_TYPE_ANY ||
			    tmp_blob.csb_cpu_type == oblob->csb_cpu_type) &&
			    !bcmp(tmp_blob.csb_cdhash,
			    oblob->csb_cdhash,
			    CS_CDHASH_LEN)) {
				/*
				 * We already have this blob:
				 * we'll return success but
				 * throw away the new blob.
				 */
				if (oblob->csb_cpu_type == CPU_TYPE_ANY) {
					/*
					 * The old blob matches this one
					 * but doesn't have any CPU type.
					 * Update it with whatever the caller
					 * provided this time.
					 */
					cs_blob_set_cpu_type(oblob, cputype);
				}

				/* The signature is still accepted, so update the
				 * generation count. */
				uip->cs_add_gen = cs_blob_generation_count;

				vnode_unlock(vp);
				if (ret_blob) {
					*ret_blob = oblob;
				}
				error = EAGAIN;
				goto out;
			} else {
				/* different blob: reject the new one */
				vnode_unlock(vp);
				error = EALREADY;
				goto out;
			}
		}
	}

	/* mark this vnode's VM object as having "signed pages" */
	kr = memory_object_signed(uip->ui_control, TRUE);
	if (kr != KERN_SUCCESS) {
		vnode_unlock(vp);
		error = ENOENT;
		goto out;
	}

	if (uip->cs_blobs == NULL) {
		/* loading 1st blob: record the file's current "modify time" */
		record_mtime = TRUE;
	}

	/* set the generation count for cs_blobs */
	uip->cs_add_gen = cs_blob_generation_count;

	/* Authenticate the PAC signature after blocking operation */
	ptrauth_utils_auth_blob_generic(
		&tmp_blob,
		sizeof(tmp_blob),
		OS_PTRAUTH_DISCRIMINATOR("ubc_cs_blob_add.blocking_op0"),
		PTRAUTH_ADDR_DIVERSIFY,
		cs_blob_sig);

	/* Update the system statistics for code signatures blobs */
	ubc_cs_blob_adjust_statistics(&tmp_blob);

	/* Update the list pointer to reference other blobs for this vnode */
	tmp_blob.csb_next = uip->cs_blobs;

#if HAS_APPLE_PAC
	/*
	 * Update all the critical pointers in the blob with the RO diversified
	 * values before updating the read-only blob with the full contents of
	 * the struct cs_blob. We need to use memcpy here as otherwise a simple
	 * assignment will cause the compiler to re-sign using the stack variable
	 * as the address diversifier.
	 */
	memcpy((void*)&tmp_blob.csb_entitlements, &signed_entitlements, sizeof(void*));
#if CODE_SIGNING_MONITOR
	memcpy((void*)&tmp_blob.csb_csm_obj, &signed_monitor_obj, sizeof(void*));
#endif
#endif
	zalloc_ro_update_elem(ZONE_ID_CS_BLOB, blob_ro, &tmp_blob);

	/* Add a fence to ensure writes to the blob are visible on all threads */
	os_atomic_thread_fence(seq_cst);

	/*
	 * Add the cs_blob to the front of the list of blobs for this vnode. We
	 * add to the front of the list, and we never remove a blob from the list
	 * which means ubc_cs_get_blobs can return whatever the top of the list
	 * is, while still keeping the list valid. Useful for if we validate a
	 * page while adding in a new blob for this vnode.
	 */
	uip->cs_blobs = blob_ro;

	/* Make sure to reload pointer from uip to double check */
	if (uip->cs_blobs->csb_next) {
		zone_require_ro(ZONE_ID_CS_BLOB, sizeof(struct cs_blob), uip->cs_blobs->csb_next);
	}

	if (cs_debug > 1) {
		proc_t p;
		const char *name = vnode_getname_printable(vp);
		p = current_proc();
		printf("CODE SIGNING: proc %d(%s) "
		    "loaded %s signatures for file (%s) "
		    "range 0x%llx:0x%llx flags 0x%x\n",
		    proc_getpid(p), p->p_comm,
		    blob_ro->csb_cpu_type == -1 ? "detached" : "embedded",
		    name,
		    blob_ro->csb_base_offset + blob_ro->csb_start_offset,
		    blob_ro->csb_base_offset + blob_ro->csb_end_offset,
		    blob_ro->csb_flags);
		vnode_putname_printable(name);
	}

	vnode_unlock(vp);

	if (record_mtime) {
		vnode_mtime(vp, &uip->cs_mtime, vfs_context_current());
	}

	if (ret_blob) {
		*ret_blob = blob_ro;
	}

	error = 0;      /* success ! */

out:
	if (error) {
		if (error != EAGAIN) {
			printf("check_signature[pid: %d]: error = %d\n", proc_getpid(current_proc()), error);
		}

		cs_blob_cleanup(&tmp_blob);
		if (blob_ro) {
			zfree_ro(ZONE_ID_CS_BLOB, blob_ro);
		}
	}

	if (error == EAGAIN) {
		/*
		 * See above:  error is EAGAIN if we were asked
		 * to add an existing blob again.  We cleaned the new
		 * blob and we want to return success.
		 */
		error = 0;
	}

	return error;
}

#if CONFIG_SUPPLEMENTAL_SIGNATURES
int
ubc_cs_blob_add_supplement(
	struct vnode    *vp,
	struct vnode    *orig_vp,
	off_t           base_offset,
	vm_address_t    *addr,
	vm_size_t       size,
	struct cs_blob  **ret_blob)
{
	kern_return_t           kr;
	struct ubc_info         *uip, *orig_uip;
	int                     error;
	struct cs_blob          tmp_blob;
	struct cs_blob          *orig_blob;
	struct cs_blob          *blob_ro = NULL;
	CS_CodeDirectory const *cd;
	off_t                   blob_start_offset, blob_end_offset;

	if (ret_blob) {
		*ret_blob = NULL;
	}

	/* Create the struct cs_blob wrapper that will be attached to the vnode.
	 * Validates the passed in blob in the process. */
	error = cs_blob_init_validated(addr, size, &tmp_blob, &cd);

	if (error != 0) {
		printf("malformed code signature supplement blob: %d\n", error);
		return error;
	}

	tmp_blob.csb_cpu_type = -1;
	tmp_blob.csb_base_offset = base_offset;

	tmp_blob.csb_reconstituted = false;

	vnode_lock(orig_vp);
	if (!UBCINFOEXISTS(orig_vp)) {
		vnode_unlock(orig_vp);
		error = ENOENT;
		goto out;
	}

	orig_uip = orig_vp->v_ubcinfo;

	/* check that the supplement's linked cdhash matches a cdhash of
	 * the target image.
	 */

	if (tmp_blob.csb_linkage_hashtype == NULL) {
		proc_t p;
		const char *iname = vnode_getname_printable(vp);
		p = current_proc();

		printf("CODE SIGNING: proc %d(%s) supplemental signature for file (%s) "
		    "is not a supplemental.\n",
		    proc_getpid(p), p->p_comm, iname);

		error = EINVAL;

		vnode_putname_printable(iname);
		vnode_unlock(orig_vp);
		goto out;
	}
	bool found_but_not_valid = false;
	for (orig_blob = ubc_get_cs_blobs(orig_vp); orig_blob != NULL;
	    orig_blob = orig_blob->csb_next) {
		if (orig_blob->csb_hashtype == tmp_blob.csb_linkage_hashtype &&
		    memcmp(orig_blob->csb_cdhash, tmp_blob.csb_linkage, CS_CDHASH_LEN) == 0) {
			// Found match!
			found_but_not_valid = ((orig_blob->csb_flags & CS_VALID) != CS_VALID);
			break;
		}
	}

	if (orig_blob == NULL || found_but_not_valid) {
		// Not found.

		proc_t p;
		const char *iname = vnode_getname_printable(vp);
		p = current_proc();

		error = (orig_blob == NULL) ? ESRCH : EPERM;

		printf("CODE SIGNING: proc %d(%s) supplemental signature for file (%s) "
		    "does not match any attached cdhash (error: %d).\n",
		    proc_getpid(p), p->p_comm, iname, error);

		vnode_putname_printable(iname);
		vnode_unlock(orig_vp);
		goto out;
	}

	vnode_unlock(orig_vp);

	blob_ro = zalloc_ro(ZONE_ID_CS_BLOB, Z_WAITOK | Z_NOFAIL);
	tmp_blob.csb_ro_addr = blob_ro;
	tmp_blob.csb_vnode = vp;

	/* AMFI needs to see the current blob state at the RO address. */
	zalloc_ro_update_elem(ZONE_ID_CS_BLOB, blob_ro, &tmp_blob);

	// validate the signature against policy!
#if CONFIG_MACF
	unsigned int signer_type = tmp_blob.csb_signer_type;
	error = mac_vnode_check_supplemental_signature(vp, &tmp_blob, orig_vp, orig_blob, &signer_type);

	tmp_blob.csb_signer_type = signer_type;

	if (error) {
		if (cs_debug) {
			printf("check_supplemental_signature[pid: %d], error = %d\n", proc_getpid(current_proc()), error);
		}
		goto out;
	}
#endif

	// We allowed the supplemental signature blob so
	// copy the platform bit or team-id from the linked signature and whether or not the original is developer code
	tmp_blob.csb_platform_binary = 0;
	tmp_blob.csb_platform_path = 0;
	if (orig_blob->csb_platform_binary == 1) {
		tmp_blob.csb_platform_binary = orig_blob->csb_platform_binary;
		tmp_blob.csb_platform_path = orig_blob->csb_platform_path;
	} else if (orig_blob->csb_teamid != NULL) {
		vm_size_t teamid_size = strlen(orig_blob->csb_teamid) + 1;
		tmp_blob.csb_supplement_teamid = kalloc_data(teamid_size, Z_WAITOK);
		if (tmp_blob.csb_supplement_teamid == NULL) {
			error = ENOMEM;
			goto out;
		}
		strlcpy(tmp_blob.csb_supplement_teamid, orig_blob->csb_teamid, teamid_size);
	}
	tmp_blob.csb_flags = (orig_blob->csb_flags & CS_DEV_CODE);

	// Validate the blob's coverage
	blob_start_offset = tmp_blob.csb_base_offset + tmp_blob.csb_start_offset;
	blob_end_offset = tmp_blob.csb_base_offset + tmp_blob.csb_end_offset;

	if (blob_start_offset >= blob_end_offset || blob_start_offset < 0 || blob_end_offset <= 0) {
		/* reject empty or backwards blob */
		error = EINVAL;
		goto out;
	}

	vnode_lock(vp);
	if (!UBCINFOEXISTS(vp)) {
		vnode_unlock(vp);
		error = ENOENT;
		goto out;
	}
	uip = vp->v_ubcinfo;

	struct cs_blob *existing = uip->cs_blob_supplement;
	if (existing != NULL) {
		if (tmp_blob.csb_hashtype == existing->csb_hashtype &&
		    memcmp(tmp_blob.csb_cdhash, existing->csb_cdhash, CS_CDHASH_LEN) == 0) {
			error = EAGAIN; // non-fatal
		} else {
			error = EALREADY; // fatal
		}

		vnode_unlock(vp);
		goto out;
	}

	/* mark this vnode's VM object as having "signed pages" */
	kr = memory_object_signed(uip->ui_control, TRUE);
	if (kr != KERN_SUCCESS) {
		vnode_unlock(vp);
		error = ENOENT;
		goto out;
	}


	/* We still adjust statistics even for supplemental blobs, as they
	 * consume memory just the same. */
	ubc_cs_blob_adjust_statistics(&tmp_blob);
	/* Unlike regular cs_blobs, we only ever support one supplement. */
	tmp_blob.csb_next = NULL;
	zalloc_ro_update_elem(ZONE_ID_CS_BLOB, blob_ro, &tmp_blob);

	os_atomic_thread_fence(seq_cst); // Fence to prevent reordering here
	uip->cs_blob_supplement = blob_ro;

	/* Make sure to reload pointer from uip to double check */
	if (__improbable(uip->cs_blob_supplement->csb_next)) {
		panic("csb_next does not match expected NULL value");
	}

	vnode_unlock(vp);


	if (cs_debug > 1) {
		proc_t p;
		const char *name = vnode_getname_printable(vp);
		p = current_proc();
		printf("CODE SIGNING: proc %d(%s) "
		    "loaded supplemental signature for file (%s) "
		    "range 0x%llx:0x%llx\n",
		    proc_getpid(p), p->p_comm,
		    name,
		    blob_ro->csb_base_offset + blob_ro->csb_start_offset,
		    blob_ro->csb_base_offset + blob_ro->csb_end_offset);
		vnode_putname_printable(name);
	}

	if (ret_blob) {
		*ret_blob = blob_ro;
	}

	error = 0; // Success!
out:
	if (error) {
		if (cs_debug) {
			printf("ubc_cs_blob_add_supplement[pid: %d]: error = %d\n", proc_getpid(current_proc()), error);
		}

		cs_blob_cleanup(&tmp_blob);
		if (blob_ro) {
			zfree_ro(ZONE_ID_CS_BLOB, blob_ro);
		}
	}

	if (error == EAGAIN) {
		/* We were asked to add an existing blob.
		 * We cleaned up and ignore the attempt. */
		error = 0;
	}

	return error;
}
#endif



void
csvnode_print_debug(struct vnode *vp)
{
	const char      *name = NULL;
	struct ubc_info *uip;
	struct cs_blob *blob;

	name = vnode_getname_printable(vp);
	if (name) {
		printf("csvnode: name: %s\n", name);
		vnode_putname_printable(name);
	}

	vnode_lock_spin(vp);

	if (!UBCINFOEXISTS(vp)) {
		blob = NULL;
		goto out;
	}

	uip = vp->v_ubcinfo;
	for (blob = uip->cs_blobs; blob != NULL; blob = blob->csb_next) {
		printf("csvnode: range: %lu -> %lu flags: 0x%08x platform: %s path: %s team: %s\n",
		    (unsigned long)blob->csb_start_offset,
		    (unsigned long)blob->csb_end_offset,
		    blob->csb_flags,
		    blob->csb_platform_binary ? "yes" : "no",
		    blob->csb_platform_path ? "yes" : "no",
		    blob->csb_teamid ? blob->csb_teamid : "<NO-TEAM>");
	}

out:
	vnode_unlock(vp);
}

#if CONFIG_SUPPLEMENTAL_SIGNATURES
struct cs_blob *
ubc_cs_blob_get_supplement(
	struct vnode    *vp,
	off_t           offset)
{
	struct cs_blob *blob;
	off_t offset_in_blob;

	vnode_lock_spin(vp);

	if (!UBCINFOEXISTS(vp)) {
		blob = NULL;
		goto out;
	}

	blob = vp->v_ubcinfo->cs_blob_supplement;

	if (blob == NULL) {
		// no supplemental blob
		goto out;
	}


	if (offset != -1) {
		offset_in_blob = offset - blob->csb_base_offset;
		if (offset_in_blob < blob->csb_start_offset || offset_in_blob >= blob->csb_end_offset) {
			// not actually covered by this blob
			blob = NULL;
		}
	}

out:
	vnode_unlock(vp);

	return blob;
}
#endif

struct cs_blob *
ubc_cs_blob_get(
	struct vnode    *vp,
	cpu_type_t      cputype,
	cpu_subtype_t   cpusubtype,
	off_t           offset)
{
	struct cs_blob  *blob;
	off_t offset_in_blob;

	vnode_lock_spin(vp);

	if (!UBCINFOEXISTS(vp)) {
		blob = NULL;
		goto out;
	}

	for (blob = ubc_get_cs_blobs(vp);
	    blob != NULL;
	    blob = blob->csb_next) {
		if (cputype != -1 && blob->csb_cpu_type == cputype && (cpusubtype == -1 || blob->csb_cpu_subtype == (cpusubtype & ~CPU_SUBTYPE_MASK))) {
			break;
		}
		if (offset != -1) {
			offset_in_blob = offset - blob->csb_base_offset;
			if (offset_in_blob >= blob->csb_start_offset &&
			    offset_in_blob < blob->csb_end_offset) {
				/* our offset is covered by this blob */
				break;
			}
		}
	}

out:
	vnode_unlock(vp);

	return blob;
}

void
ubc_cs_free_and_vnode_unlock(
	vnode_t vp)
{
	struct ubc_info *uip = vp->v_ubcinfo;
	struct cs_blob  *cs_blobs, *blob, *next_blob;

	if (!(uip->ui_flags & UI_CSBLOBINVALID)) {
		vnode_unlock(vp);
		return;
	}

	uip->ui_flags &= ~UI_CSBLOBINVALID;

	cs_blobs = uip->cs_blobs;
	uip->cs_blobs = NULL;

#if CHECK_CS_VALIDATION_BITMAP
	ubc_cs_validation_bitmap_deallocate( uip );
#endif

#if CONFIG_SUPPLEMENTAL_SIGNATURES
	struct cs_blob  *cs_blob_supplement = uip->cs_blob_supplement;
	uip->cs_blob_supplement = NULL;
#endif

	vnode_unlock(vp);

	for (blob = cs_blobs;
	    blob != NULL;
	    blob = next_blob) {
		next_blob = blob->csb_next;
		os_atomic_add(&cs_blob_count, -1, relaxed);
		os_atomic_add(&cs_blob_size, -blob->csb_mem_size, relaxed);
		cs_blob_ro_free(blob);
	}

#if CONFIG_SUPPLEMENTAL_SIGNATURES
	if (cs_blob_supplement != NULL) {
		os_atomic_add(&cs_blob_count, -1, relaxed);
		os_atomic_add(&cs_blob_size, -cs_blob_supplement->csb_mem_size, relaxed);
		cs_blob_supplement_free(cs_blob_supplement);
	}
#endif
}

static void
ubc_cs_free(
	struct ubc_info *uip)
{
	struct cs_blob  *blob, *next_blob;

	for (blob = uip->cs_blobs;
	    blob != NULL;
	    blob = next_blob) {
		next_blob = blob->csb_next;
		os_atomic_add(&cs_blob_count, -1, relaxed);
		os_atomic_add(&cs_blob_size, -blob->csb_mem_size, relaxed);
		cs_blob_ro_free(blob);
	}
#if CHECK_CS_VALIDATION_BITMAP
	ubc_cs_validation_bitmap_deallocate( uip );
#endif
	uip->cs_blobs = NULL;
#if CONFIG_SUPPLEMENTAL_SIGNATURES
	if (uip->cs_blob_supplement != NULL) {
		blob = uip->cs_blob_supplement;
		os_atomic_add(&cs_blob_count, -1, relaxed);
		os_atomic_add(&cs_blob_size, -blob->csb_mem_size, relaxed);
		cs_blob_supplement_free(uip->cs_blob_supplement);
		uip->cs_blob_supplement = NULL;
	}
#endif
}

/* check cs blob generation on vnode
 * returns:
 *    0         : Success, the cs_blob attached is current
 *    ENEEDAUTH : Generation count mismatch. Needs authentication again.
 */
int
ubc_cs_generation_check(
	struct vnode    *vp)
{
	int retval = ENEEDAUTH;

	vnode_lock_spin(vp);

	if (UBCINFOEXISTS(vp) && vp->v_ubcinfo->cs_add_gen == cs_blob_generation_count) {
		retval = 0;
	}

	vnode_unlock(vp);
	return retval;
}

int
ubc_cs_blob_revalidate(
	struct vnode    *vp,
	struct cs_blob *blob,
	struct image_params *imgp,
	int flags,
	uint32_t platform
	)
{
	int error = 0;
	const CS_CodeDirectory *cd = NULL;
	const CS_GenericBlob *entitlements = NULL;
	const CS_GenericBlob *der_entitlements = NULL;
	size_t size;
	assert(vp != NULL);
	assert(blob != NULL);

	if ((blob->csb_flags & CS_VALID) == 0) {
		// If the blob attached to the vnode was invalidated, don't try to revalidate it
		// Blob invalidation only occurs when the file that the blob is attached to is
		// opened for writing, giving us a signal that the file is modified.
		printf("CODESIGNING: can not re-validate a previously invalidated blob, reboot or create a new file.\n");
		error = EPERM;
		goto out;
	}

	size = blob->csb_mem_size;
	error = cs_validate_csblob((const uint8_t *)blob->csb_mem_kaddr,
	    size, &cd, &entitlements, &der_entitlements);
	if (error) {
		if (cs_debug) {
			printf("CODESIGNING: csblob invalid: %d\n", error);
		}
		goto out;
	}

	unsigned int cs_flags = (ntohl(cd->flags) & CS_ALLOWED_MACHO) | CS_VALID;
	unsigned int signer_type = CS_SIGNER_TYPE_UNKNOWN;

	if (blob->csb_reconstituted) {
		/*
		 * Code signatures that have been modified after validation
		 * cannot be revalidated inline from their in-memory blob.
		 *
		 * That's okay, though, because the only path left that relies
		 * on revalidation of existing in-memory blobs is the legacy
		 * detached signature database path, which only exists on macOS,
		 * which does not do reconstitution of any kind.
		 */
		if (cs_debug) {
			printf("CODESIGNING: revalidate: not inline revalidating reconstituted signature.\n");
		}

		/*
		 * EAGAIN tells the caller that they may reread the code
		 * signature and try attaching it again, which is the same
		 * thing they would do if there was no cs_blob yet in the
		 * first place.
		 *
		 * Conveniently, after ubc_cs_blob_add did a successful
		 * validation, it will detect that a matching cs_blob (cdhash,
		 * offset, arch etc.) already exists, and return success
		 * without re-adding a cs_blob to the vnode.
		 */
		return EAGAIN;
	}

	/* callout to mac_vnode_check_signature */
#if CONFIG_MACF
	error = mac_vnode_check_signature(vp, blob, imgp, &cs_flags, &signer_type, flags, platform);
	if (cs_debug && error) {
		printf("revalidate: check_signature[pid: %d], error = %d\n", proc_getpid(current_proc()), error);
	}
#else
	(void)flags;
	(void)signer_type;
#endif

	/* update generation number if success */
	vnode_lock_spin(vp);
	struct cs_signer_info signer_info = {
		.csb_flags = cs_flags,
		.csb_signer_type = signer_type
	};
	zalloc_ro_update_field(ZONE_ID_CS_BLOB, blob, csb_signer_info, &signer_info);
	if (UBCINFOEXISTS(vp)) {
		if (error == 0) {
			vp->v_ubcinfo->cs_add_gen = cs_blob_generation_count;
		} else {
			vp->v_ubcinfo->cs_add_gen = 0;
		}
	}

	vnode_unlock(vp);

out:
	return error;
}

void
cs_blob_reset_cache()
{
	/* incrementing odd no by 2 makes sure '0' is never reached. */
	OSAddAtomic(+2, &cs_blob_generation_count);
	printf("Reseting cs_blob cache from all vnodes. \n");
}

struct cs_blob *
ubc_get_cs_blobs(
	struct vnode    *vp)
{
	struct ubc_info *uip;
	struct cs_blob  *blobs;

	/*
	 * No need to take the vnode lock here.  The caller must be holding
	 * a reference on the vnode (via a VM mapping or open file descriptor),
	 * so the vnode will not go away.  The ubc_info stays until the vnode
	 * goes away.  And we only modify "blobs" by adding to the head of the
	 * list.
	 * The ubc_info could go away entirely if the vnode gets reclaimed as
	 * part of a forced unmount.  In the case of a code-signature validation
	 * during a page fault, the "paging_in_progress" reference on the VM
	 * object guarantess that the vnode pager (and the ubc_info) won't go
	 * away during the fault.
	 * Other callers need to protect against vnode reclaim by holding the
	 * vnode lock, for example.
	 */

	if (!UBCINFOEXISTS(vp)) {
		blobs = NULL;
		goto out;
	}

	uip = vp->v_ubcinfo;
	blobs = uip->cs_blobs;
	if (blobs != NULL) {
		cs_blob_require(blobs, vp);
	}

out:
	return blobs;
}

#if CONFIG_SUPPLEMENTAL_SIGNATURES
struct cs_blob *
ubc_get_cs_supplement(
	struct vnode    *vp)
{
	struct ubc_info *uip;
	struct cs_blob  *blob;

	/*
	 * No need to take the vnode lock here.  The caller must be holding
	 * a reference on the vnode (via a VM mapping or open file descriptor),
	 * so the vnode will not go away.  The ubc_info stays until the vnode
	 * goes away.
	 * The ubc_info could go away entirely if the vnode gets reclaimed as
	 * part of a forced unmount.  In the case of a code-signature validation
	 * during a page fault, the "paging_in_progress" reference on the VM
	 * object guarantess that the vnode pager (and the ubc_info) won't go
	 * away during the fault.
	 * Other callers need to protect against vnode reclaim by holding the
	 * vnode lock, for example.
	 */

	if (!UBCINFOEXISTS(vp)) {
		blob = NULL;
		goto out;
	}

	uip = vp->v_ubcinfo;
	blob = uip->cs_blob_supplement;
	if (blob != NULL) {
		cs_blob_require(blob, vp);
	}

out:
	return blob;
}
#endif


void
ubc_get_cs_mtime(
	struct vnode    *vp,
	struct timespec *cs_mtime)
{
	struct ubc_info *uip;

	if (!UBCINFOEXISTS(vp)) {
		cs_mtime->tv_sec = 0;
		cs_mtime->tv_nsec = 0;
		return;
	}

	uip = vp->v_ubcinfo;
	cs_mtime->tv_sec = uip->cs_mtime.tv_sec;
	cs_mtime->tv_nsec = uip->cs_mtime.tv_nsec;
}

unsigned long cs_validate_page_no_hash = 0;
unsigned long cs_validate_page_bad_hash = 0;
static boolean_t
cs_validate_hash(
	struct cs_blob          *blobs,
	memory_object_t         pager,
	memory_object_offset_t  page_offset,
	const void              *data,
	vm_size_t               *bytes_processed,
	unsigned                *tainted)
{
	union cs_hash_union     mdctx;
	struct cs_hash const    *hashtype = NULL;
	unsigned char           actual_hash[CS_HASH_MAX_SIZE];
	unsigned char           expected_hash[CS_HASH_MAX_SIZE];
	boolean_t               found_hash;
	struct cs_blob          *blob;
	const CS_CodeDirectory  *cd;
	const unsigned char     *hash;
	boolean_t               validated;
	off_t                   offset; /* page offset in the file */
	size_t                  size;
	off_t                   codeLimit = 0;
	const char              *lower_bound, *upper_bound;
	vm_offset_t             kaddr, blob_addr;

	/* retrieve the expected hash */
	found_hash = FALSE;

	for (blob = blobs;
	    blob != NULL;
	    blob = blob->csb_next) {
		offset = page_offset - blob->csb_base_offset;
		if (offset < blob->csb_start_offset ||
		    offset >= blob->csb_end_offset) {
			/* our page is not covered by this blob */
			continue;
		}

		/* blob data has been released */
		kaddr = (vm_offset_t)blob->csb_mem_kaddr;
		if (kaddr == 0) {
			continue;
		}

		blob_addr = kaddr + blob->csb_mem_offset;
		lower_bound = CAST_DOWN(char *, blob_addr);
		upper_bound = lower_bound + blob->csb_mem_size;

		cd = blob->csb_cd;
		if (cd != NULL) {
			/* all CD's that have been injected is already validated */

			hashtype = blob->csb_hashtype;
			if (hashtype == NULL) {
				panic("unknown hash type ?");
			}
			if (hashtype->cs_digest_size > sizeof(actual_hash)) {
				panic("hash size too large");
			}
			if (offset & ((1U << blob->csb_hash_pageshift) - 1)) {
				panic("offset not aligned to cshash boundary");
			}

			codeLimit = ntohl(cd->codeLimit);

			hash = hashes(cd, (uint32_t)(offset >> blob->csb_hash_pageshift),
			    hashtype->cs_size,
			    lower_bound, upper_bound);
			if (hash != NULL) {
				bcopy(hash, expected_hash, hashtype->cs_size);
				found_hash = TRUE;
			}

			break;
		}
	}

	if (found_hash == FALSE) {
		/*
		 * We can't verify this page because there is no signature
		 * for it (yet).  It's possible that this part of the object
		 * is not signed, or that signatures for that part have not
		 * been loaded yet.
		 * Report that the page has not been validated and let the
		 * caller decide if it wants to accept it or not.
		 */
		cs_validate_page_no_hash++;
		if (cs_debug > 1) {
			printf("CODE SIGNING: cs_validate_page: "
			    "mobj %p off 0x%llx: no hash to validate !?\n",
			    pager, page_offset);
		}
		validated = FALSE;
		*tainted = 0;
	} else {
		*tainted = 0;

		size = (1U << blob->csb_hash_pageshift);
		*bytes_processed = size;

		const uint32_t *asha1, *esha1;
		if ((off_t)(offset + size) > codeLimit) {
			/* partial page at end of segment */
			assert(offset < codeLimit);
			size = (size_t) (codeLimit & (size - 1));
			*tainted |= CS_VALIDATE_NX;
		}

		hashtype->cs_init(&mdctx);

		if (blob->csb_hash_firstlevel_pageshift) {
			const unsigned char *partial_data = (const unsigned char *)data;
			size_t i;
			for (i = 0; i < size;) {
				union cs_hash_union     partialctx;
				unsigned char partial_digest[CS_HASH_MAX_SIZE];
				size_t partial_size = MIN(size - i, (1U << blob->csb_hash_firstlevel_pageshift));

				hashtype->cs_init(&partialctx);
				hashtype->cs_update(&partialctx, partial_data, partial_size);
				hashtype->cs_final(partial_digest, &partialctx);

				/* Update cumulative multi-level hash */
				hashtype->cs_update(&mdctx, partial_digest, hashtype->cs_size);
				partial_data = partial_data + partial_size;
				i += partial_size;
			}
		} else {
			hashtype->cs_update(&mdctx, data, size);
		}
		hashtype->cs_final(actual_hash, &mdctx);

		asha1 = (const uint32_t *) actual_hash;
		esha1 = (const uint32_t *) expected_hash;

		if (bcmp(expected_hash, actual_hash, hashtype->cs_size) != 0) {
			if (cs_debug) {
				printf("CODE SIGNING: cs_validate_page: "
				    "mobj %p off 0x%llx size 0x%lx: "
				    "actual [0x%x 0x%x 0x%x 0x%x 0x%x] != "
				    "expected [0x%x 0x%x 0x%x 0x%x 0x%x]\n",
				    pager, page_offset, size,
				    asha1[0], asha1[1], asha1[2],
				    asha1[3], asha1[4],
				    esha1[0], esha1[1], esha1[2],
				    esha1[3], esha1[4]);
			}
			cs_validate_page_bad_hash++;
			*tainted |= CS_VALIDATE_TAINTED;
		} else {
			if (cs_debug > 10) {
				printf("CODE SIGNING: cs_validate_page: "
				    "mobj %p off 0x%llx size 0x%lx: "
				    "SHA1 OK\n",
				    pager, page_offset, size);
			}
		}
		validated = TRUE;
	}

	return validated;
}

boolean_t
cs_validate_range(
	struct vnode    *vp,
	memory_object_t         pager,
	memory_object_offset_t  page_offset,
	const void              *data,
	vm_size_t               dsize,
	unsigned                *tainted)
{
	vm_size_t offset_in_range;
	boolean_t all_subranges_validated = TRUE; /* turn false if any subrange fails */

	struct cs_blob *blobs = ubc_get_cs_blobs(vp);

#if CONFIG_SUPPLEMENTAL_SIGNATURES
	if (blobs == NULL && proc_is_translated(current_proc())) {
		struct cs_blob *supp = ubc_get_cs_supplement(vp);

		if (supp != NULL) {
			blobs = supp;
		} else {
			return FALSE;
		}
	}
#endif



	*tainted = 0;

	for (offset_in_range = 0;
	    offset_in_range < dsize;
	    /* offset_in_range updated based on bytes processed */) {
		unsigned subrange_tainted = 0;
		boolean_t subrange_validated;
		vm_size_t bytes_processed = 0;

		subrange_validated = cs_validate_hash(blobs,
		    pager,
		    page_offset + offset_in_range,
		    (const void *)((const char *)data + offset_in_range),
		    &bytes_processed,
		    &subrange_tainted);

		*tainted |= subrange_tainted;

		if (bytes_processed == 0) {
			/* Cannote make forward progress, so return an error */
			all_subranges_validated = FALSE;
			break;
		} else if (subrange_validated == FALSE) {
			all_subranges_validated = FALSE;
			/* Keep going to detect other types of failures in subranges */
		}

		offset_in_range += bytes_processed;
	}

	return all_subranges_validated;
}

void
cs_validate_page(
	struct vnode            *vp,
	memory_object_t         pager,
	memory_object_offset_t  page_offset,
	const void              *data,
	int                     *validated_p,
	int                     *tainted_p,
	int                     *nx_p)
{
	vm_size_t offset_in_page;
	struct cs_blob *blobs;

	blobs = ubc_get_cs_blobs(vp);

#if CONFIG_SUPPLEMENTAL_SIGNATURES
	if (blobs == NULL && proc_is_translated(current_proc())) {
		struct cs_blob *supp = ubc_get_cs_supplement(vp);

		if (supp != NULL) {
			blobs = supp;
		}
	}
#endif

	*validated_p = VMP_CS_ALL_FALSE;
	*tainted_p = VMP_CS_ALL_FALSE;
	*nx_p = VMP_CS_ALL_FALSE;

	for (offset_in_page = 0;
	    offset_in_page < PAGE_SIZE;
	    /* offset_in_page updated based on bytes processed */) {
		unsigned subrange_tainted = 0;
		boolean_t subrange_validated;
		vm_size_t bytes_processed = 0;
		int sub_bit;

		subrange_validated = cs_validate_hash(blobs,
		    pager,
		    page_offset + offset_in_page,
		    (const void *)((const char *)data + offset_in_page),
		    &bytes_processed,
		    &subrange_tainted);

		if (bytes_processed == 0) {
			/* 4k chunk not code-signed: try next one */
			offset_in_page += FOURK_PAGE_SIZE;
			continue;
		}
		if (offset_in_page == 0 &&
		    bytes_processed > PAGE_SIZE - FOURK_PAGE_SIZE) {
			/* all processed: no 4k granularity */
			if (subrange_validated) {
				*validated_p = VMP_CS_ALL_TRUE;
			}
			if (subrange_tainted & CS_VALIDATE_TAINTED) {
				*tainted_p = VMP_CS_ALL_TRUE;
			}
			if (subrange_tainted & CS_VALIDATE_NX) {
				*nx_p = VMP_CS_ALL_TRUE;
			}
			break;
		}
		/* we only handle 4k or 16k code-signing granularity... */
		assertf(bytes_processed <= FOURK_PAGE_SIZE,
		    "vp %p blobs %p offset 0x%llx + 0x%llx bytes_processed 0x%llx\n",
		    vp, blobs, (uint64_t)page_offset,
		    (uint64_t)offset_in_page, (uint64_t)bytes_processed);
		sub_bit = 1 << (offset_in_page >> FOURK_PAGE_SHIFT);
		if (subrange_validated) {
			*validated_p |= sub_bit;
		}
		if (subrange_tainted & CS_VALIDATE_TAINTED) {
			*tainted_p |= sub_bit;
		}
		if (subrange_tainted & CS_VALIDATE_NX) {
			*nx_p |= sub_bit;
		}
		/* go to next 4k chunk */
		offset_in_page += FOURK_PAGE_SIZE;
	}

	return;
}

int
ubc_cs_getcdhash(
	vnode_t         vp,
	off_t           offset,
	unsigned char   *cdhash)
{
	struct cs_blob  *blobs, *blob;
	off_t           rel_offset;
	int             ret;

	vnode_lock(vp);

	blobs = ubc_get_cs_blobs(vp);
	for (blob = blobs;
	    blob != NULL;
	    blob = blob->csb_next) {
		/* compute offset relative to this blob */
		rel_offset = offset - blob->csb_base_offset;
		if (rel_offset >= blob->csb_start_offset &&
		    rel_offset < blob->csb_end_offset) {
			/* this blob does cover our "offset" ! */
			break;
		}
	}

	if (blob == NULL) {
		/* we didn't find a blob covering "offset" */
		ret = EBADEXEC; /* XXX any better error ? */
	} else {
		/* get the SHA1 hash of that blob */
		bcopy(blob->csb_cdhash, cdhash, sizeof(blob->csb_cdhash));
		ret = 0;
	}

	vnode_unlock(vp);

	return ret;
}

boolean_t
ubc_cs_is_range_codesigned(
	vnode_t                 vp,
	mach_vm_offset_t        start,
	mach_vm_size_t          size)
{
	struct cs_blob          *csblob;
	mach_vm_offset_t        blob_start;
	mach_vm_offset_t        blob_end;

	if (vp == NULL) {
		/* no file: no code signature */
		return FALSE;
	}
	if (size == 0) {
		/* no range: no code signature */
		return FALSE;
	}
	if (start + size < start) {
		/* overflow */
		return FALSE;
	}

	csblob = ubc_cs_blob_get(vp, -1, -1, start);
	if (csblob == NULL) {
		return FALSE;
	}

	/*
	 * We currently check if the range is covered by a single blob,
	 * which should always be the case for the dyld shared cache.
	 * If we ever want to make this routine handle other cases, we
	 * would have to iterate if the blob does not cover the full range.
	 */
	blob_start = (mach_vm_offset_t) (csblob->csb_base_offset +
	    csblob->csb_start_offset);
	blob_end = (mach_vm_offset_t) (csblob->csb_base_offset +
	    csblob->csb_end_offset);
	if (blob_start > start || blob_end < (start + size)) {
		/* range not fully covered by this code-signing blob */
		return FALSE;
	}

	return TRUE;
}

#if CHECK_CS_VALIDATION_BITMAP
#define stob(s) (((atop_64(round_page_64(s))) + 07) >> 3)
extern  boolean_t       root_fs_upgrade_try;

/*
 * Should we use the code-sign bitmap to avoid repeated code-sign validation?
 * Depends:
 * a) Is the target vnode on the root filesystem?
 * b) Has someone tried to mount the root filesystem read-write?
 * If answers are (a) yes AND (b) no, then we can use the bitmap.
 */
#define USE_CODE_SIGN_BITMAP(vp)        ( (vp != NULL) && (vp->v_mount != NULL) && (vp->v_mount->mnt_flag & MNT_ROOTFS) && !root_fs_upgrade_try)
kern_return_t
ubc_cs_validation_bitmap_allocate(
	vnode_t         vp)
{
	kern_return_t   kr = KERN_SUCCESS;
	struct ubc_info *uip;
	char            *target_bitmap;
	vm_object_size_t        bitmap_size;

	if (!USE_CODE_SIGN_BITMAP(vp) || (!UBCINFOEXISTS(vp))) {
		kr = KERN_INVALID_ARGUMENT;
	} else {
		uip = vp->v_ubcinfo;

		if (uip->cs_valid_bitmap == NULL) {
			bitmap_size = stob(uip->ui_size);
			target_bitmap = (char*) kalloc_data((vm_size_t)bitmap_size, Z_WAITOK | Z_ZERO);
			if (target_bitmap == 0) {
				kr = KERN_NO_SPACE;
			} else {
				kr = KERN_SUCCESS;
			}
			if (kr == KERN_SUCCESS) {
				uip->cs_valid_bitmap = (void*)target_bitmap;
				uip->cs_valid_bitmap_size = bitmap_size;
			}
		}
	}
	return kr;
}

kern_return_t
ubc_cs_check_validation_bitmap(
	vnode_t                 vp,
	memory_object_offset_t          offset,
	int                     optype)
{
	kern_return_t   kr = KERN_SUCCESS;

	if (!USE_CODE_SIGN_BITMAP(vp) || !UBCINFOEXISTS(vp)) {
		kr = KERN_INVALID_ARGUMENT;
	} else {
		struct ubc_info *uip = vp->v_ubcinfo;
		char            *target_bitmap = uip->cs_valid_bitmap;

		if (target_bitmap == NULL) {
			kr = KERN_INVALID_ARGUMENT;
		} else {
			uint64_t        bit, byte;
			bit = atop_64( offset );
			byte = bit >> 3;

			if (byte > uip->cs_valid_bitmap_size) {
				kr = KERN_INVALID_ARGUMENT;
			} else {
				if (optype == CS_BITMAP_SET) {
					target_bitmap[byte] |= (1 << (bit & 07));
					kr = KERN_SUCCESS;
				} else if (optype == CS_BITMAP_CLEAR) {
					target_bitmap[byte] &= ~(1 << (bit & 07));
					kr = KERN_SUCCESS;
				} else if (optype == CS_BITMAP_CHECK) {
					if (target_bitmap[byte] & (1 << (bit & 07))) {
						kr = KERN_SUCCESS;
					} else {
						kr = KERN_FAILURE;
					}
				}
			}
		}
	}
	return kr;
}

void
ubc_cs_validation_bitmap_deallocate(
	struct ubc_info *uip)
{
	if (uip->cs_valid_bitmap != NULL) {
		kfree_data(uip->cs_valid_bitmap, (vm_size_t)uip->cs_valid_bitmap_size);
		uip->cs_valid_bitmap = NULL;
	}
}
#else
kern_return_t
ubc_cs_validation_bitmap_allocate(__unused vnode_t vp)
{
	return KERN_INVALID_ARGUMENT;
}

kern_return_t
ubc_cs_check_validation_bitmap(
	__unused struct vnode *vp,
	__unused memory_object_offset_t offset,
	__unused int optype)
{
	return KERN_INVALID_ARGUMENT;
}

void
ubc_cs_validation_bitmap_deallocate(__unused struct ubc_info *uip)
{
	return;
}
#endif /* CHECK_CS_VALIDATION_BITMAP */

#if CODE_SIGNING_MONITOR

kern_return_t
cs_associate_blob_with_mapping(
	void                    *pmap,
	vm_map_offset_t         start,
	vm_map_size_t           size,
	vm_object_offset_t      offset,
	void                    *blobs_p)
{
	off_t                   blob_start_offset, blob_end_offset;
	kern_return_t           kr;
	struct cs_blob          *blobs, *blob;
	vm_offset_t             kaddr;
	void                    *monitor_sig_obj = NULL;

	if (csm_enabled() == false) {
		return KERN_NOT_SUPPORTED;
	}

	blobs = (struct cs_blob *)blobs_p;

	for (blob = blobs;
	    blob != NULL;
	    blob = blob->csb_next) {
		blob_start_offset = (blob->csb_base_offset +
		    blob->csb_start_offset);
		blob_end_offset = (blob->csb_base_offset +
		    blob->csb_end_offset);
		if ((off_t) offset < blob_start_offset ||
		    (off_t) offset >= blob_end_offset ||
		    (off_t) (offset + size) <= blob_start_offset ||
		    (off_t) (offset + size) > blob_end_offset) {
			continue;
		}

		kaddr = (vm_offset_t)blob->csb_mem_kaddr;
		if (kaddr == 0) {
			/* blob data has been released */
			continue;
		}

		monitor_sig_obj = blob->csb_csm_obj;
		if (monitor_sig_obj == NULL) {
			continue;
		}

		break;
	}

	if (monitor_sig_obj != NULL) {
		vm_offset_t segment_offset = offset - blob_start_offset;
		kr = csm_associate_code_signature(pmap, monitor_sig_obj, start, size, segment_offset);
	} else {
		kr = KERN_CODESIGN_ERROR;
	}

	return kr;
}

#endif /* CODE_SIGNING_MONITOR */