1 /* Copyright (c) (2022) Apple Inc. All rights reserved. 2 * 3 * corecrypto is licensed under Apple Inc.’s Internal Use License Agreement (which 4 * is contained in the License.txt file distributed with corecrypto) and only to 5 * people who accept that license. IMPORTANT: Any license rights granted to you by 6 * Apple Inc. (if any) are limited to internal use within your organization only on 7 * devices and computers you own or control, for the sole purpose of verifying the 8 * security characteristics and correct functioning of the Apple Software. You may 9 * not, directly or indirectly, redistribute the Apple Software or any portions thereof. 10 */ 11 12 #ifndef _CORECRYPTO_CCMODE_GCM_INTERNAL_H_ 13 #define _CORECRYPTO_CCMODE_GCM_INTERNAL_H_ 14 15 #include <corecrypto/ccmode_impl.h> 16 17 #define CCGCM_IV_NBYTES 12 18 #define CCGCM_BLOCK_NBYTES 16 19 20 /* Create a gcm key from a gcm mode object. 21 * key must point to at least sizeof(CCMODE_GCM_KEY(ecb)) bytes of free 22 * storage. */ 23 int ccmode_gcm_init(const struct ccmode_gcm *gcm, ccgcm_ctx *ctx, 24 size_t rawkey_len, const void *rawkey); 25 int ccmode_gcm_set_iv(ccgcm_ctx *ctx, size_t iv_nbytes, const void *iv); 26 int ccmode_gcm_aad(ccgcm_ctx *ctx, size_t nbytes, const void *in); 27 int ccmode_gcm_decrypt(ccgcm_ctx *ctx, size_t nbytes, const void *in, 28 void *out); 29 int ccmode_gcm_encrypt(ccgcm_ctx *ctx, size_t nbytes, const void *in, 30 void *out); 31 32 /*! 33 * @function ccmode_gcm_finalize() finalizes AES-GCM call sequence 34 * @param key encryption or decryption key 35 * @param tag_nbytes length of tag in bytes 36 * @param tag authentication tag 37 * @result 0=success or non zero= error 38 * @discussion For decryption, the tag parameter must be the expected-tag. A secure compare is performed between the provided expected-tag and the computed-tag. If they are the same, 0 is returned. Otherwise, non zero is returned. For encryption, tag is output and provides the authentication tag. 39 * 40 */ 41 int ccmode_gcm_finalize(ccgcm_ctx *key, size_t tag_nbytes, void *tag); 42 int ccmode_gcm_reset(ccgcm_ctx *key); 43 44 #define GCM_ECB_KEY_SIZE(ECB_ENCRYPT) \ 45 ((5 * ccn_sizeof_size((ECB_ENCRYPT)->block_size)) \ 46 + ccn_sizeof_size((ECB_ENCRYPT)->size)) 47 48 #define CCGCM_FLAGS_INIT_WITH_IV 1 49 50 // Here is what the structure looks like in memory 51 // [ temp space | length | *ecb | *ecb_key | table | ecb_key ] 52 // size of table depends on the implementation (VNG vs factory) 53 // currently, VNG and factory share the same "header" described here 54 // VNG may add additional data after the header 55 struct _ccmode_gcm_key { 56 // 5 blocks of temp space. 57 unsigned char H[16]; /* multiplier */ 58 unsigned char X[16]; /* accumulator */ 59 unsigned char Y[16]; /* counter */ 60 unsigned char Y_0[16]; /* initial counter */ 61 unsigned char buf[16]; /* buffer for stuff */ 62 63 // State and length 64 uint16_t state; /* state the GCM code is in */ 65 uint16_t flags; /* flags (persistent across reset) */ 66 uint32_t buf_nbytes; /* length of data in buf */ 67 68 uint64_t aad_nbytes; /* 64-bit counter used for IV and AAD */ 69 uint64_t text_nbytes; /* 64-bit counter for the plaintext PT */ 70 71 // ECB 72 const struct ccmode_ecb *ecb; // ecb mode 73 // Pointer to the ECB key in the buffer 74 void *ecb_key; // address of the ecb_key in u, set in init function 75 int encdec; //is it an encrypt or decrypt object 76 77 // Buffer with ECB key and H table if applicable 78 CC_ALIGNED(16) unsigned char u[]; // ecb key + tables 79 }; 80 81 /* Macros for accessing a CCMODE_GCM_KEY. 82 * Common to the generic (factory) and the VNG implementation 83 */ 84 85 #define _CCMODE_GCM_KEY(K) ((struct _ccmode_gcm_key *)(K)) 86 #define CCMODE_GCM_KEY_H(K) (_CCMODE_GCM_KEY(K)->H) 87 #define CCMODE_GCM_KEY_X(K) (_CCMODE_GCM_KEY(K)->X) 88 #define CCMODE_GCM_KEY_Y(K) (_CCMODE_GCM_KEY(K)->Y) 89 #define CCMODE_GCM_KEY_Y_0(K) (_CCMODE_GCM_KEY(K)->Y_0) 90 #define CCMODE_GCM_KEY_PAD_LEN(K) (_CCMODE_GCM_KEY(K)->buf_nbytes) 91 #define CCMODE_GCM_KEY_PAD(K) (_CCMODE_GCM_KEY(K)->buf) 92 93 #define _CCMODE_GCM_ECB_MODE(K) ((struct _ccmode_gcm_key *)(K)) 94 #define CCMODE_GCM_KEY_ECB(K) (_CCMODE_GCM_ECB_MODE(K)->ecb) 95 #define CCMODE_GCM_KEY_ECB_KEY(K) ((ccecb_ctx *)_CCMODE_GCM_ECB_MODE(K)->ecb_key) // set in init function 96 97 #define CCMODE_GCM_STATE_IV 1 98 #define CCMODE_GCM_STATE_AAD 2 99 #define CCMODE_GCM_STATE_TEXT 3 100 #define CCMODE_GCM_STATE_FINAL 4 101 102 void ccmode_gcm_gf_mult(const unsigned char *a, const unsigned char *b, unsigned char *c); 103 void ccmode_gcm_gf_mult_32(const unsigned char *a, const unsigned char *b, unsigned char *c); 104 void ccmode_gcm_gf_mult_64(const unsigned char *a, const unsigned char *b, unsigned char *c); 105 void ccmode_gcm_mult_h(ccgcm_ctx *key, unsigned char *I); 106 107 CC_NONNULL_ALL 108 void inc_uint(uint8_t *buf, size_t nbytes); 109 110 CC_NONNULL_ALL 111 void ccmode_gcm_update_pad(ccgcm_ctx *key); 112 113 CC_NONNULL_ALL 114 void ccmode_gcm_aad_finalize(ccgcm_ctx *key); 115 116 #endif // _CORECRYPTO_CCMODE_GCM_INTERNAL_H_ 117