xref: /xnu-12377.81.4/bsd/sys/cprotect.h (revision 043036a2b3718f7f0be807e2870f8f47d3fa0796)

/*
 * Copyright (c) 2009-2023 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@
 */

#ifndef _SYS_CPROTECT_H_
#define _SYS_CPROTECT_H_

#ifdef KERNEL_PRIVATE

#include <sys/cdefs.h>
#include <sys/param.h>
#include <sys/buf.h>
#include <sys/kdebug.h>
#include <crypto/aes.h>
#include <stdbool.h>
#include <uuid/uuid.h>
#include <libkern/crypto/sha1.h>

__BEGIN_DECLS

#define CP_CODE(code) FSDBG_CODE(DBG_CONTENT_PROT, code)
/*
 * Class DBG_FSYSTEM == 0x03
 * Subclass DBG_CONTENT_PROT == 0xCF
 * These debug codes are of the form 0x03CFzzzz
 */

enum {
	CPDBG_OFFSET_IO = CP_CODE(0),   /* 0x03CF0000 */
};

/* normally the debug events are no-ops */
#define CP_DEBUG(x, a, b, c, d, e) do {} while (0);

/* dev kernels only! */
#if !SECURE_KERNEL

/* KDEBUG events used by content protection subsystem */
#if 0
#undef CP_DEBUG
#define CP_DEBUG KERNEL_DEBUG_CONSTANT
#endif

#endif

#define CP_MAX_WRAPPEDKEYSIZE     128   /* The size of the largest allowed key */
#define VFS_CP_MAX_CACHEBUFLEN    64    /* Maximum size of the cached key */

/* lock events from AppleKeyStore */
enum {
	CP_ACTION_LOCKED         = 0,
	CP_ACTION_UNLOCKED       = 1,
	CP_ACTION_EP_INVALIDATED = 2,
	CP_ACTION_CX_EXPIRED     = 3,
};
/*
 * Ideally, cp_key_store_action_t would be an enum, but we cannot fix
 * that until AppleKeyStore is updated.
 */
typedef int cp_key_store_action_t;

/*
 * It was once the case (and it may still be the case) where the lock
 * state got conflated with the possible actions/events that
 * AppleKeyStore can send.  For that reason, the locked states below
 * should numerically match their corresponding actions above.
 */
typedef unsigned char cp_lock_state_t;
enum {
	CP_LOCKED_STATE         = 0,
	CP_UNLOCKED_STATE       = 1,
};

typedef unsigned char cp_ep_state_t;
enum {
	CP_EP_INVALIDATED       = 0,
};

typedef unsigned char cp_cx_state_t;
enum {
	CP_CX_EXPIRED           = 0,
};

typedef uint32_t cp_key_class_t;
typedef uint32_t cp_key_os_version_t;
typedef uint16_t cp_key_revision_t;
typedef uint64_t cp_crypto_id_t;

typedef struct cprotect *cprotect_t;
typedef struct cpx *cpx_t;

#ifdef BSD_KERNEL_PRIVATE
/* Not for consumption outside of XNU */
typedef uint32_t cpx_flags_t;
/*
 * This is a CPX structure with a fixed-length key buffer. We need this defined in a header
 * so that we can use this structure to allocate the memory for the zone(s) properly.
 */
typedef struct fcpx {
#ifdef DEBUG
	uint32_t                cpx_magic1;
#endif // DEBUG
	aes_encrypt_ctx         *cpx_iv_aes_ctx_ptr;// Context used for generating the IV
	cpx_flags_t             cpx_flags;
	uint16_t                cpx_max_key_len;
	uint16_t                cpx_key_len;
	uint8_t                 cpx_cached_key[VFS_CP_MAX_CACHEBUFLEN];
	//Fixed length all the way through
} fcpx_t;

#endif // BSD_KERNEL_PRIVATE

typedef struct cp_key {
	uint8_t len;
	void *key;
} cp_key_t;

/* Interface to AKS kext */
typedef struct {
	void     *key;
	unsigned key_len;
	void     *iv_key;
	unsigned iv_key_len;
	uint32_t flags;
} cp_raw_key_s;

typedef cp_raw_key_s* cp_raw_key_t;

typedef struct {
	void     *key;
	unsigned key_len;
	cp_key_class_t dp_class;
} cp_wrapped_key_s;

typedef cp_wrapped_key_s* cp_wrapped_key_t;

typedef struct {
	union {
		ino64_t                 inode;
		cp_crypto_id_t  crypto_id;
	};
	uint32_t                        volume;
	pid_t                           pid;
	uid_t                           uid;
	cp_key_revision_t       key_revision;
} cp_cred_s;

typedef cp_cred_s* cp_cred_t;

/* The wrappers are invoked on the AKS kext */
typedef int unwrapper_t(cp_cred_t access, const cp_wrapped_key_t wrapped_key_in, cp_raw_key_t key_out);
typedef int rewrapper_t(cp_cred_t access, cp_key_class_t dp_class, const cp_wrapped_key_t wrapped_key_in, cp_wrapped_key_t wrapped_key_out);
typedef int new_key_t(cp_cred_t access, cp_key_class_t dp_class, cp_raw_key_t key_out, cp_wrapped_key_t wrapped_key_out);
typedef int invalidater_t(cp_cred_t access); /* invalidates keys */
typedef int backup_key_t(cp_cred_t access, const cp_wrapped_key_t wrapped_key_in, cp_wrapped_key_t wrapped_key_out);

/*
 * Flags for Interaction between AKS / Kernel
 * These are twiddled via the input/output structs in the above
 * wrapper/unwrapper functions.
 */
#define CP_RAW_KEY_WRAPPEDKEY   0x00000001

/*
 * Function prototypes for kexts to interface with our internal cprotect
 * fields;  cpx provides opacity and allows us to modify behavior internally
 * without requiring kext changes.
 */
cpx_t cpx_alloc(size_t key_size, bool needs_ctx);
int cpx_alloc_ctx(cpx_t cpx);
void cpx_free_ctx(cpx_t cpx);
void cpx_init(cpx_t, size_t key_len);
void cpx_init_ctx_ptr(cpx_t cpx);
void cpx_free(cpx_t);
void cpx_writeprotect(cpx_t cpx);
__attribute__((const)) size_t cpx_size(size_t key_len);
__attribute__((pure)) bool cpx_is_sep_wrapped_key(const struct cpx *);
void cpx_set_is_sep_wrapped_key(struct cpx *, bool);
__attribute__((pure)) bool cpx_is_composite_key(const struct cpx *);
void cpx_set_is_composite_key(struct cpx *, bool);
__attribute__((pure)) bool cpx_use_offset_for_iv(const struct cpx *);
void cpx_set_use_offset_for_iv(struct cpx *, bool);
__attribute__((pure)) bool cpx_synthetic_offset_for_iv(const struct cpx *);
void cpx_set_synthetic_offset_for_iv(struct cpx *, bool);
__attribute__((pure)) uint16_t cpx_key_len(const struct cpx *);
void cpx_set_key_len(struct cpx *, uint16_t key_len);
__attribute__((pure)) void *cpx_key(const struct cpx *);
aes_encrypt_ctx *cpx_iv_aes_ctx(struct cpx *);
void cpx_flush(cpx_t cpx);
bool cpx_can_copy(const struct cpx *src, const struct cpx *dst);
void cpx_copy(const struct cpx *src, cpx_t dst);
uint16_t cpx_max_key_len(const struct cpx *cpx);
bool cpx_has_key(const struct cpx *cpx);
size_t cpx_sizex(const struct cpx *cpx);
void cpx_set_aes_iv_key(struct cpx *cpx, void *iv_key);

int cp_key_store_action(cp_key_store_action_t);
int cp_key_store_action_for_volume(uuid_t volume_uuid, cp_key_store_action_t action);
cp_key_os_version_t cp_os_version(void);
// Should be cp_key_class_t but HFS has a conflicting definition
int cp_is_valid_class(int isdir, int32_t protectionclass);

__END_DECLS

#endif /* KERNEL_PRIVATE */
#endif /* !_SYS_CPROTECT_H_ */