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 /* see inner.h */ 28 void 29 br_tls_phash(void *dst, size_t len, 30 const br_hash_class *dig, 31 const void *secret, size_t secret_len, const char *label, 32 size_t seed_num, const br_tls_prf_seed_chunk *seed) 33 { 34 unsigned char *buf; 35 unsigned char tmp[64], a[64]; 36 br_hmac_key_context kc; 37 br_hmac_context hc; 38 size_t label_len, hlen, u; 39 40 if (len == 0) { 41 return; 42 } 43 buf = dst; 44 for (label_len = 0; label[label_len]; label_len ++); 45 hlen = br_digest_size(dig); 46 br_hmac_key_init(&kc, dig, secret, secret_len); 47 br_hmac_init(&hc, &kc, 0); 48 br_hmac_update(&hc, label, label_len); 49 for (u = 0; u < seed_num; u ++) { 50 br_hmac_update(&hc, seed[u].data, seed[u].len); 51 } 52 br_hmac_out(&hc, a); 53 for (;;) { 54 br_hmac_init(&hc, &kc, 0); 55 br_hmac_update(&hc, a, hlen); 56 br_hmac_update(&hc, label, label_len); 57 for (u = 0; u < seed_num; u ++) { 58 br_hmac_update(&hc, seed[u].data, seed[u].len); 59 } 60 br_hmac_out(&hc, tmp); 61 for (u = 0; u < hlen && u < len; u ++) { 62 buf[u] ^= tmp[u]; 63 } 64 buf += u; 65 len -= u; 66 if (len == 0) { 67 return; 68 } 69 br_hmac_init(&hc, &kc, 0); 70 br_hmac_update(&hc, a, hlen); 71 br_hmac_out(&hc, a); 72 } 73 } 74