1 /* $OpenBSD: hmac.c,v 1.10 2014/01/31 16:39:19 tedu 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 18 #include <sys/types.h> 19 #include <string.h> 20 21 #include "buffer.h" 22 #include "digest.h" 23 #include "hmac.h" 24 25 struct ssh_hmac_ctx { 26 int alg; 27 struct ssh_digest_ctx *ictx; 28 struct ssh_digest_ctx *octx; 29 struct ssh_digest_ctx *digest; 30 u_char *buf; 31 size_t buf_len; 32 }; 33 34 size_t 35 ssh_hmac_bytes(int alg) 36 { 37 return ssh_digest_bytes(alg); 38 } 39 40 struct ssh_hmac_ctx * 41 ssh_hmac_start(int alg) 42 { 43 struct ssh_hmac_ctx *ret; 44 45 if ((ret = calloc(1, sizeof(*ret))) == NULL) 46 return NULL; 47 ret->alg = alg; 48 if ((ret->ictx = ssh_digest_start(alg)) == NULL || 49 (ret->octx = ssh_digest_start(alg)) == NULL || 50 (ret->digest = ssh_digest_start(alg)) == NULL) 51 goto fail; 52 ret->buf_len = ssh_digest_blocksize(ret->ictx); 53 if ((ret->buf = calloc(1, ret->buf_len)) == NULL) 54 goto fail; 55 return ret; 56 fail: 57 ssh_hmac_free(ret); 58 return NULL; 59 } 60 61 int 62 ssh_hmac_init(struct ssh_hmac_ctx *ctx, const void *key, size_t klen) 63 { 64 size_t i; 65 66 /* reset ictx and octx if no is key given */ 67 if (key != NULL) { 68 /* truncate long keys */ 69 if (klen <= ctx->buf_len) 70 memcpy(ctx->buf, key, klen); 71 else if (ssh_digest_memory(ctx->alg, key, klen, ctx->buf, 72 ctx->buf_len) < 0) 73 return -1; 74 for (i = 0; i < ctx->buf_len; i++) 75 ctx->buf[i] ^= 0x36; 76 if (ssh_digest_update(ctx->ictx, ctx->buf, ctx->buf_len) < 0) 77 return -1; 78 for (i = 0; i < ctx->buf_len; i++) 79 ctx->buf[i] ^= 0x36 ^ 0x5c; 80 if (ssh_digest_update(ctx->octx, ctx->buf, ctx->buf_len) < 0) 81 return -1; 82 explicit_bzero(ctx->buf, ctx->buf_len); 83 } 84 /* start with ictx */ 85 if (ssh_digest_copy_state(ctx->ictx, ctx->digest) < 0) 86 return -1; 87 return 0; 88 } 89 90 int 91 ssh_hmac_update(struct ssh_hmac_ctx *ctx, const void *m, size_t mlen) 92 { 93 return ssh_digest_update(ctx->digest, m, mlen); 94 } 95 96 int 97 ssh_hmac_update_buffer(struct ssh_hmac_ctx *ctx, const Buffer *b) 98 { 99 return ssh_digest_update_buffer(ctx->digest, b); 100 } 101 102 int 103 ssh_hmac_final(struct ssh_hmac_ctx *ctx, u_char *d, size_t dlen) 104 { 105 size_t len; 106 107 len = ssh_digest_bytes(ctx->alg); 108 if (dlen < len || 109 ssh_digest_final(ctx->digest, ctx->buf, len)) 110 return -1; 111 /* switch to octx */ 112 if (ssh_digest_copy_state(ctx->octx, ctx->digest) < 0 || 113 ssh_digest_update(ctx->digest, ctx->buf, len) < 0 || 114 ssh_digest_final(ctx->digest, d, dlen) < 0) 115 return -1; 116 return 0; 117 } 118 119 void 120 ssh_hmac_free(struct ssh_hmac_ctx *ctx) 121 { 122 if (ctx != NULL) { 123 ssh_digest_free(ctx->ictx); 124 ssh_digest_free(ctx->octx); 125 ssh_digest_free(ctx->digest); 126 if (ctx->buf) { 127 explicit_bzero(ctx->buf, ctx->buf_len); 128 free(ctx->buf); 129 } 130 explicit_bzero(ctx, sizeof(*ctx)); 131 free(ctx); 132 } 133 } 134 135 #ifdef TEST 136 137 /* cc -DTEST hmac.c digest.c buffer.c cleanup.c fatal.c log.c xmalloc.c -lcrypto */ 138 static void 139 hmac_test(void *key, size_t klen, void *m, size_t mlen, u_char *e, size_t elen) 140 { 141 struct ssh_hmac_ctx *ctx; 142 size_t i; 143 u_char digest[16]; 144 145 if ((ctx = ssh_hmac_start(SSH_DIGEST_MD5)) == NULL) 146 printf("ssh_hmac_start failed"); 147 if (ssh_hmac_init(ctx, key, klen) < 0 || 148 ssh_hmac_update(ctx, m, mlen) < 0 || 149 ssh_hmac_final(ctx, digest, sizeof(digest)) < 0) 150 printf("ssh_hmac_xxx failed"); 151 ssh_hmac_free(ctx); 152 153 if (memcmp(e, digest, elen)) { 154 for (i = 0; i < elen; i++) 155 printf("[%zd] %2.2x %2.2x\n", i, e[i], digest[i]); 156 printf("mismatch\n"); 157 } else 158 printf("ok\n"); 159 } 160 161 int 162 main(int argc, char **argv) 163 { 164 /* try test vectors from RFC 2104 */ 165 166 u_char key1[16] = { 167 0xb, 0xb, 0xb, 0xb, 0xb, 0xb, 0xb, 0xb, 168 0xb, 0xb, 0xb, 0xb, 0xb, 0xb, 0xb, 0xb }; 169 u_char *data1 = "Hi There"; 170 u_char dig1[16] = { 171 0x92, 0x94, 0x72, 0x7a, 0x36, 0x38, 0xbb, 0x1c, 172 0x13, 0xf4, 0x8e, 0xf8, 0x15, 0x8b, 0xfc, 0x9d }; 173 174 u_char *key2 = "Jefe"; 175 u_char *data2 = "what do ya want for nothing?"; 176 u_char dig2[16] = { 177 0x75, 0x0c, 0x78, 0x3e, 0x6a, 0xb0, 0xb5, 0x03, 178 0xea, 0xa8, 0x6e, 0x31, 0x0a, 0x5d, 0xb7, 0x38 }; 179 180 u_char key3[16]; 181 u_char data3[50]; 182 u_char dig3[16] = { 183 0x56, 0xbe, 0x34, 0x52, 0x1d, 0x14, 0x4c, 0x88, 184 0xdb, 0xb8, 0xc7, 0x33, 0xf0, 0xe8, 0xb3, 0xf6 }; 185 memset(key3, 0xaa, sizeof(key3)); 186 memset(data3, 0xdd, sizeof(data3)); 187 188 hmac_test(key1, sizeof(key1), data1, strlen(data1), dig1, sizeof(dig1)); 189 hmac_test(key2, strlen(key2), data2, strlen(data2), dig2, sizeof(dig2)); 190 hmac_test(key3, sizeof(key3), data3, sizeof(data3), dig3, sizeof(dig3)); 191 192 return 0; 193 } 194 195 #endif 196