1 /* 2 * Copyright (c) 2016 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 static inline size_t 28 block_size(const br_hash_class *dig) 29 { 30 unsigned ls; 31 32 ls = (unsigned)(dig->desc >> BR_HASHDESC_LBLEN_OFF) 33 & BR_HASHDESC_LBLEN_MASK; 34 return (size_t)1 << ls; 35 } 36 37 static void 38 process_key(const br_hash_class **hc, void *ks, 39 const void *key, size_t key_len, unsigned bb) 40 { 41 unsigned char tmp[256]; 42 size_t blen, u; 43 44 blen = block_size(*hc); 45 memcpy(tmp, key, key_len); 46 for (u = 0; u < key_len; u ++) { 47 tmp[u] ^= (unsigned char)bb; 48 } 49 memset(tmp + key_len, bb, blen - key_len); 50 (*hc)->init(hc); 51 (*hc)->update(hc, tmp, blen); 52 (*hc)->state(hc, ks); 53 } 54 55 /* see bearssl.h */ 56 void 57 br_hmac_key_init(br_hmac_key_context *kc, 58 const br_hash_class *dig, const void *key, size_t key_len) 59 { 60 br_hash_compat_context hc; 61 unsigned char kbuf[64]; 62 63 kc->dig_vtable = dig; 64 hc.vtable = dig; 65 if (key_len > block_size(dig)) { 66 dig->init(&hc.vtable); 67 dig->update(&hc.vtable, key, key_len); 68 dig->out(&hc.vtable, kbuf); 69 key = kbuf; 70 key_len = br_digest_size(dig); 71 } 72 process_key(&hc.vtable, kc->ksi, key, key_len, 0x36); 73 process_key(&hc.vtable, kc->kso, key, key_len, 0x5C); 74 } 75 76 /* see bearssl.h */ 77 void 78 br_hmac_init(br_hmac_context *ctx, 79 const br_hmac_key_context *kc, size_t out_len) 80 { 81 const br_hash_class *dig; 82 size_t blen, hlen; 83 84 dig = kc->dig_vtable; 85 blen = block_size(dig); 86 dig->init(&ctx->dig.vtable); 87 dig->set_state(&ctx->dig.vtable, kc->ksi, (uint64_t)blen); 88 memcpy(ctx->kso, kc->kso, sizeof kc->kso); 89 hlen = br_digest_size(dig); 90 if (out_len > 0 && out_len < hlen) { 91 hlen = out_len; 92 } 93 ctx->out_len = hlen; 94 } 95 96 /* see bearssl.h */ 97 void 98 br_hmac_update(br_hmac_context *ctx, const void *data, size_t len) 99 { 100 ctx->dig.vtable->update(&ctx->dig.vtable, data, len); 101 } 102 103 /* see bearssl.h */ 104 size_t 105 br_hmac_out(const br_hmac_context *ctx, void *out) 106 { 107 const br_hash_class *dig; 108 br_hash_compat_context hc; 109 unsigned char tmp[64]; 110 size_t blen, hlen; 111 112 dig = ctx->dig.vtable; 113 dig->out(&ctx->dig.vtable, tmp); 114 blen = block_size(dig); 115 dig->init(&hc.vtable); 116 dig->set_state(&hc.vtable, ctx->kso, (uint64_t)blen); 117 hlen = br_digest_size(dig); 118 dig->update(&hc.vtable, tmp, hlen); 119 dig->out(&hc.vtable, tmp); 120 memcpy(out, tmp, ctx->out_len); 121 return ctx->out_len; 122 } 123