1 /* $OpenBSD: hmac.c,v 1.16 2026/02/14 00:18:34 jsg Exp $ */ 2 /* 3 * Copyright (c) 2014 Markus Friedl. All rights reserved. 4 * 5 * Permission to use, copy, modify, and distribute this software for any 6 * purpose with or without fee is hereby granted, provided that the above 7 * copyright notice and this permission notice appear in all copies. 8 * 9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16 */ 17 #include "includes.h" 18 __RCSID("$NetBSD: hmac.c,v 1.10 2026/04/08 18:58:40 christos Exp $"); 19 20 #include <sys/types.h> 21 22 #include <stdlib.h> 23 #include <string.h> 24 25 #include "digest.h" 26 #include "hmac.h" 27 28 struct ssh_hmac_ctx { 29 int alg; 30 struct ssh_digest_ctx *ictx; 31 struct ssh_digest_ctx *octx; 32 struct ssh_digest_ctx *digest; 33 u_char *buf; 34 size_t buf_len; 35 }; 36 37 size_t 38 ssh_hmac_bytes(int alg) 39 { 40 return ssh_digest_bytes(alg); 41 } 42 43 struct ssh_hmac_ctx * 44 ssh_hmac_start(int alg) 45 { 46 struct ssh_hmac_ctx *ret; 47 48 if ((ret = calloc(1, sizeof(*ret))) == NULL) 49 return NULL; 50 ret->alg = alg; 51 if ((ret->ictx = ssh_digest_start(alg)) == NULL || 52 (ret->octx = ssh_digest_start(alg)) == NULL || 53 (ret->digest = ssh_digest_start(alg)) == NULL) 54 goto fail; 55 ret->buf_len = ssh_digest_blocksize(ret->ictx); 56 if ((ret->buf = calloc(1, ret->buf_len)) == NULL) 57 goto fail; 58 return ret; 59 fail: 60 ssh_hmac_free(ret); 61 return NULL; 62 } 63 64 int 65 ssh_hmac_init(struct ssh_hmac_ctx *ctx, const void *key, size_t klen) 66 { 67 size_t i; 68 69 /* reset ictx and octx if no is key given */ 70 if (key != NULL) { 71 /* truncate long keys */ 72 if (klen <= ctx->buf_len) 73 memcpy(ctx->buf, key, klen); 74 else if (ssh_digest_memory(ctx->alg, key, klen, ctx->buf, 75 ctx->buf_len) < 0) 76 return -1; 77 for (i = 0; i < ctx->buf_len; i++) 78 ctx->buf[i] ^= 0x36; 79 if (ssh_digest_update(ctx->ictx, ctx->buf, ctx->buf_len) < 0) 80 return -1; 81 for (i = 0; i < ctx->buf_len; i++) 82 ctx->buf[i] ^= 0x36 ^ 0x5c; 83 if (ssh_digest_update(ctx->octx, ctx->buf, ctx->buf_len) < 0) 84 return -1; 85 explicit_bzero(ctx->buf, ctx->buf_len); 86 } 87 /* start with ictx */ 88 if (ssh_digest_copy_state(ctx->ictx, ctx->digest) < 0) 89 return -1; 90 return 0; 91 } 92 93 int 94 ssh_hmac_update(struct ssh_hmac_ctx *ctx, const void *m, size_t mlen) 95 { 96 return ssh_digest_update(ctx->digest, m, mlen); 97 } 98 99 int 100 ssh_hmac_update_buffer(struct ssh_hmac_ctx *ctx, const struct sshbuf *b) 101 { 102 return ssh_digest_update_buffer(ctx->digest, b); 103 } 104 105 int 106 ssh_hmac_final(struct ssh_hmac_ctx *ctx, u_char *d, size_t dlen) 107 { 108 size_t len; 109 110 len = ssh_digest_bytes(ctx->alg); 111 if (dlen < len || 112 ssh_digest_final(ctx->digest, ctx->buf, len)) 113 return -1; 114 /* switch to octx */ 115 if (ssh_digest_copy_state(ctx->octx, ctx->digest) < 0 || 116 ssh_digest_update(ctx->digest, ctx->buf, len) < 0 || 117 ssh_digest_final(ctx->digest, d, dlen) < 0) 118 return -1; 119 return 0; 120 } 121 122 void 123 ssh_hmac_free(struct ssh_hmac_ctx *ctx) 124 { 125 if (ctx != NULL) { 126 ssh_digest_free(ctx->ictx); 127 ssh_digest_free(ctx->octx); 128 ssh_digest_free(ctx->digest); 129 if (ctx->buf) { 130 explicit_bzero(ctx->buf, ctx->buf_len); 131 free(ctx->buf); 132 } 133 freezero(ctx, sizeof(*ctx)); 134 } 135 } 136 137 #ifdef TEST 138 139 /* cc -DTEST hmac.c digest.c buffer.c cleanup.c fatal.c log.c xmalloc.c -lcrypto */ 140 static void 141 hmac_test(void *key, size_t klen, void *m, size_t mlen, u_char *e, size_t elen) 142 { 143 struct ssh_hmac_ctx *ctx; 144 size_t i; 145 u_char digest[16]; 146 147 if ((ctx = ssh_hmac_start(SSH_DIGEST_MD5)) == NULL) 148 printf("ssh_hmac_start failed"); 149 if (ssh_hmac_init(ctx, key, klen) < 0 || 150 ssh_hmac_update(ctx, m, mlen) < 0 || 151 ssh_hmac_final(ctx, digest, sizeof(digest)) < 0) 152 printf("ssh_hmac_xxx failed"); 153 ssh_hmac_free(ctx); 154 155 if (memcmp(e, digest, elen)) { 156 for (i = 0; i < elen; i++) 157 printf("[%zu] %2.2x %2.2x\n", i, e[i], digest[i]); 158 printf("mismatch\n"); 159 } else 160 printf("ok\n"); 161 } 162 163 int 164 main(int argc, char **argv) 165 { 166 /* try test vectors from RFC 2104 */ 167 168 u_char key1[16] = { 169 0xb, 0xb, 0xb, 0xb, 0xb, 0xb, 0xb, 0xb, 170 0xb, 0xb, 0xb, 0xb, 0xb, 0xb, 0xb, 0xb }; 171 u_char *data1 = "Hi There"; 172 u_char dig1[16] = { 173 0x92, 0x94, 0x72, 0x7a, 0x36, 0x38, 0xbb, 0x1c, 174 0x13, 0xf4, 0x8e, 0xf8, 0x15, 0x8b, 0xfc, 0x9d }; 175 176 u_char *key2 = "Jefe"; 177 u_char *data2 = "what do ya want for nothing?"; 178 u_char dig2[16] = { 179 0x75, 0x0c, 0x78, 0x3e, 0x6a, 0xb0, 0xb5, 0x03, 180 0xea, 0xa8, 0x6e, 0x31, 0x0a, 0x5d, 0xb7, 0x38 }; 181 182 u_char key3[16]; 183 u_char data3[50]; 184 u_char dig3[16] = { 185 0x56, 0xbe, 0x34, 0x52, 0x1d, 0x14, 0x4c, 0x88, 186 0xdb, 0xb8, 0xc7, 0x33, 0xf0, 0xe8, 0xb3, 0xf6 }; 187 memset(key3, 0xaa, sizeof(key3)); 188 memset(data3, 0xdd, sizeof(data3)); 189 190 hmac_test(key1, sizeof(key1), data1, strlen(data1), dig1, sizeof(dig1)); 191 hmac_test(key2, strlen(key2), data2, strlen(data2), dig2, sizeof(dig2)); 192 hmac_test(key3, sizeof(key3), data3, sizeof(data3), dig3, sizeof(dig3)); 193 194 return 0; 195 } 196 197 #endif 198
Indexes created Fri Sep 18 00:27:12 UTC 2026