1 /* 2 * Copyright (c) 2017 Thomas Pornin <pornin@bolet.org> 3 * 4 * Permission is hereby granted, free of charge, to any person obtaining 5 * a copy of this software and associated documentation files (the 6 * "Software"), to deal in the Software without restriction, including 7 * without limitation the rights to use, copy, modify, merge, publish, 8 * distribute, sublicense, and/or sell copies of the Software, and to 9 * permit persons to whom the Software is furnished to do so, subject to 10 * the following conditions: 11 * 12 * The above copyright notice and this permission notice shall be 13 * included in all copies or substantial portions of the Software. 14 * 15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 16 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 17 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 18 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS 19 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN 20 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN 21 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 22 * SOFTWARE. 23 */ 24 25 #include "inner.h" 26 27 /* see bearssl_block.h */ 28 void 29 br_aes_big_ctrcbc_init(br_aes_big_ctrcbc_keys *ctx, 30 const void *key, size_t len) 31 { 32 ctx->vtable = &br_aes_big_ctrcbc_vtable; 33 ctx->num_rounds = br_aes_keysched(ctx->skey, key, len); 34 } 35 36 static void 37 xorbuf(void *dst, const void *src, size_t len) 38 { 39 unsigned char *d; 40 const unsigned char *s; 41 42 d = dst; 43 s = src; 44 while (len -- > 0) { 45 *d ++ ^= *s ++; 46 } 47 } 48 49 /* see bearssl_block.h */ 50 void 51 br_aes_big_ctrcbc_ctr(const br_aes_big_ctrcbc_keys *ctx, 52 void *ctr, void *data, size_t len) 53 { 54 unsigned char *buf, *bctr; 55 uint32_t cc0, cc1, cc2, cc3; 56 57 buf = data; 58 bctr = ctr; 59 cc3 = br_dec32be(bctr + 0); 60 cc2 = br_dec32be(bctr + 4); 61 cc1 = br_dec32be(bctr + 8); 62 cc0 = br_dec32be(bctr + 12); 63 while (len > 0) { 64 unsigned char tmp[16]; 65 uint32_t carry; 66 67 br_enc32be(tmp + 0, cc3); 68 br_enc32be(tmp + 4, cc2); 69 br_enc32be(tmp + 8, cc1); 70 br_enc32be(tmp + 12, cc0); 71 br_aes_big_encrypt(ctx->num_rounds, ctx->skey, tmp); 72 xorbuf(buf, tmp, 16); 73 buf += 16; 74 len -= 16; 75 cc0 ++; 76 carry = (~(cc0 | -cc0)) >> 31; 77 cc1 += carry; 78 carry &= (~(cc1 | -cc1)) >> 31; 79 cc2 += carry; 80 carry &= (~(cc2 | -cc2)) >> 31; 81 cc3 += carry; 82 } 83 br_enc32be(bctr + 0, cc3); 84 br_enc32be(bctr + 4, cc2); 85 br_enc32be(bctr + 8, cc1); 86 br_enc32be(bctr + 12, cc0); 87 } 88 89 /* see bearssl_block.h */ 90 void 91 br_aes_big_ctrcbc_mac(const br_aes_big_ctrcbc_keys *ctx, 92 void *cbcmac, const void *data, size_t len) 93 { 94 const unsigned char *buf; 95 96 buf = data; 97 while (len > 0) { 98 xorbuf(cbcmac, buf, 16); 99 br_aes_big_encrypt(ctx->num_rounds, ctx->skey, cbcmac); 100 buf += 16; 101 len -= 16; 102 } 103 } 104 105 /* see bearssl_block.h */ 106 void 107 br_aes_big_ctrcbc_encrypt(const br_aes_big_ctrcbc_keys *ctx, 108 void *ctr, void *cbcmac, void *data, size_t len) 109 { 110 br_aes_big_ctrcbc_ctr(ctx, ctr, data, len); 111 br_aes_big_ctrcbc_mac(ctx, cbcmac, data, len); 112 } 113 114 /* see bearssl_block.h */ 115 void 116 br_aes_big_ctrcbc_decrypt(const br_aes_big_ctrcbc_keys *ctx, 117 void *ctr, void *cbcmac, void *data, size_t len) 118 { 119 br_aes_big_ctrcbc_mac(ctx, cbcmac, data, len); 120 br_aes_big_ctrcbc_ctr(ctx, ctr, data, len); 121 } 122 123 /* see bearssl_block.h */ 124 const br_block_ctrcbc_class br_aes_big_ctrcbc_vtable = { 125 sizeof(br_aes_big_ctrcbc_keys), 126 16, 127 4, 128 (void (*)(const br_block_ctrcbc_class **, const void *, size_t)) 129 &br_aes_big_ctrcbc_init, 130 (void (*)(const br_block_ctrcbc_class *const *, 131 void *, void *, void *, size_t)) 132 &br_aes_big_ctrcbc_encrypt, 133 (void (*)(const br_block_ctrcbc_class *const *, 134 void *, void *, void *, size_t)) 135 &br_aes_big_ctrcbc_decrypt, 136 (void (*)(const br_block_ctrcbc_class *const *, 137 void *, void *, size_t)) 138 &br_aes_big_ctrcbc_ctr, 139 (void (*)(const br_block_ctrcbc_class *const *, 140 void *, const void *, size_t)) 141 &br_aes_big_ctrcbc_mac 142 }; 143