1 /* $OpenBSD: hmac.c,v 1.14 2020/02/26 13:40:09 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 18 #include <sys/types.h> 19 #include <string.h> 20 #include <stdlib.h> 21 22 #include "sshbuf.h" 23 #include "digest.h" 24 #include "hmac.h" 25 26 struct ssh_hmac_ctx { 27 int alg; 28 struct ssh_digest_ctx *ictx; 29 struct ssh_digest_ctx *octx; 30 struct ssh_digest_ctx *digest; 31 u_char *buf; 32 size_t buf_len; 33 }; 34 35 size_t 36 ssh_hmac_bytes(int alg) 37 { 38 return ssh_digest_bytes(alg); 39 } 40 41 struct ssh_hmac_ctx * 42 ssh_hmac_start(int alg) 43 { 44 struct ssh_hmac_ctx *ret; 45 46 if ((ret = calloc(1, sizeof(*ret))) == NULL) 47 return NULL; 48 ret->alg = alg; 49 if ((ret->ictx = ssh_digest_start(alg)) == NULL || 50 (ret->octx = ssh_digest_start(alg)) == NULL || 51 (ret->digest = ssh_digest_start(alg)) == NULL) 52 goto fail; 53 ret->buf_len = ssh_digest_blocksize(ret->ictx); 54 if ((ret->buf = calloc(1, ret->buf_len)) == NULL) 55 goto fail; 56 return ret; 57 fail: 58 ssh_hmac_free(ret); 59 return NULL; 60 } 61 62 int 63 ssh_hmac_init(struct ssh_hmac_ctx *ctx, const void *key, size_t klen) 64 { 65 size_t i; 66 67 /* reset ictx and octx if no is key given */ 68 if (key != NULL) { 69 /* truncate long keys */ 70 if (klen <= ctx->buf_len) 71 memcpy(ctx->buf, key, klen); 72 else if (ssh_digest_memory(ctx->alg, key, klen, ctx->buf, 73 ctx->buf_len) < 0) 74 return -1; 75 for (i = 0; i < ctx->buf_len; i++) 76 ctx->buf[i] ^= 0x36; 77 if (ssh_digest_update(ctx->ictx, ctx->buf, ctx->buf_len) < 0) 78 return -1; 79 for (i = 0; i < ctx->buf_len; i++) 80 ctx->buf[i] ^= 0x36 ^ 0x5c; 81 if (ssh_digest_update(ctx->octx, ctx->buf, ctx->buf_len) < 0) 82 return -1; 83 explicit_bzero(ctx->buf, ctx->buf_len); 84 } 85 /* start with ictx */ 86 if (ssh_digest_copy_state(ctx->ictx, ctx->digest) < 0) 87 return -1; 88 return 0; 89 } 90 91 int 92 ssh_hmac_update(struct ssh_hmac_ctx *ctx, const void *m, size_t mlen) 93 { 94 return ssh_digest_update(ctx->digest, m, mlen); 95 } 96 97 int 98 ssh_hmac_update_buffer(struct ssh_hmac_ctx *ctx, const struct sshbuf *b) 99 { 100 return ssh_digest_update_buffer(ctx->digest, b); 101 } 102 103 int 104 ssh_hmac_final(struct ssh_hmac_ctx *ctx, u_char *d, size_t dlen) 105 { 106 size_t len; 107 108 len = ssh_digest_bytes(ctx->alg); 109 if (dlen < len || 110 ssh_digest_final(ctx->digest, ctx->buf, len)) 111 return -1; 112 /* switch to octx */ 113 if (ssh_digest_copy_state(ctx->octx, ctx->digest) < 0 || 114 ssh_digest_update(ctx->digest, ctx->buf, len) < 0 || 115 ssh_digest_final(ctx->digest, d, dlen) < 0) 116 return -1; 117 return 0; 118 } 119 120 void 121 ssh_hmac_free(struct ssh_hmac_ctx *ctx) 122 { 123 if (ctx != NULL) { 124 ssh_digest_free(ctx->ictx); 125 ssh_digest_free(ctx->octx); 126 ssh_digest_free(ctx->digest); 127 if (ctx->buf) { 128 explicit_bzero(ctx->buf, ctx->buf_len); 129 free(ctx->buf); 130 } 131 freezero(ctx, sizeof(*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("[%zu] %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