crypto/openssh/hmac.c

   1 /* $OpenBSD: hmac.c,v 1.12 2015/03/24 20:03:44 markus 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 "includes.h"
  19
  20 #include <sys/types.h>
  21 #include <string.h>
  22
  23 #include "sshbuf.h"
  24 #include "digest.h"
  25 #include "hmac.h"
  26
  27 struct ssh_hmac_ctx {
  28         int                      alg;
  29         struct ssh_digest_ctx   *ictx;
  30         struct ssh_digest_ctx   *octx;
  31         struct ssh_digest_ctx   *digest;
  32         u_char                  *buf;
  33         size_t                   buf_len;
  34 };
  35
  36 size_t
  37 ssh_hmac_bytes(int alg)
  38 {
  39         return ssh_digest_bytes(alg);
  40 }
  41
  42 struct ssh_hmac_ctx *
  43 ssh_hmac_start(int alg)
  44 {
  45         struct ssh_hmac_ctx     *ret;
  46
  47         if ((ret = calloc(1, sizeof(*ret))) == NULL)
  48                 return NULL;
  49         ret->alg = alg;
  50         if ((ret->ictx = ssh_digest_start(alg)) == NULL ||
  51             (ret->octx = ssh_digest_start(alg)) == NULL ||
  52             (ret->digest = ssh_digest_start(alg)) == NULL)
  53                 goto fail;
  54         ret->buf_len = ssh_digest_blocksize(ret->ictx);
  55         if ((ret->buf = calloc(1, ret->buf_len)) == NULL)
  56                 goto fail;
  57         return ret;
  58 fail:
  59         ssh_hmac_free(ret);
  60         return NULL;
  61 }
  62
  63 int
  64 ssh_hmac_init(struct ssh_hmac_ctx *ctx, const void *key, size_t klen)
  65 {
  66         size_t i;
  67
  68         /* reset ictx and octx if no is key given */
  69         if (key != NULL) {
  70                 /* truncate long keys */
  71                 if (klen <= ctx->buf_len)
  72                         memcpy(ctx->buf, key, klen);
  73                 else if (ssh_digest_memory(ctx->alg, key, klen, ctx->buf,
  74                     ctx->buf_len) < 0)
  75                         return -1;
  76                 for (i = 0; i < ctx->buf_len; i++)
  77                         ctx->buf[i] ^= 0x36;
  78                 if (ssh_digest_update(ctx->ictx, ctx->buf, ctx->buf_len) < 0)
  79                         return -1;
  80                 for (i = 0; i < ctx->buf_len; i++)
  81                         ctx->buf[i] ^= 0x36 ^ 0x5c;
  82                 if (ssh_digest_update(ctx->octx, ctx->buf, ctx->buf_len) < 0)
  83                         return -1;
  84                 explicit_bzero(ctx->buf, ctx->buf_len);
  85         }
  86         /* start with ictx */
  87         if (ssh_digest_copy_state(ctx->ictx, ctx->digest) < 0)
  88                 return -1;
  89         return 0;
  90 }
  91
  92 int
  93 ssh_hmac_update(struct ssh_hmac_ctx *ctx, const void *m, size_t mlen)
  94 {
  95         return ssh_digest_update(ctx->digest, m, mlen);
  96 }
  97
  98 int
  99 ssh_hmac_update_buffer(struct ssh_hmac_ctx *ctx, const struct sshbuf *b)
 100 {
 101         return ssh_digest_update_buffer(ctx->digest, b);
 102 }
 103
 104 int
 105 ssh_hmac_final(struct ssh_hmac_ctx *ctx, u_char *d, size_t dlen)
 106 {
 107         size_t len;
 108
 109         len = ssh_digest_bytes(ctx->alg);
 110         if (dlen < len ||
 111             ssh_digest_final(ctx->digest, ctx->buf, len))
 112                 return -1;
 113         /* switch to octx */
 114         if (ssh_digest_copy_state(ctx->octx, ctx->digest) < 0 ||
 115             ssh_digest_update(ctx->digest, ctx->buf, len) < 0 ||
 116             ssh_digest_final(ctx->digest, d, dlen) < 0)
 117                 return -1;
 118         return 0;
 119 }
 120
 121 void
 122 ssh_hmac_free(struct ssh_hmac_ctx *ctx)
 123 {
 124         if (ctx != NULL) {
 125                 ssh_digest_free(ctx->ictx);
 126                 ssh_digest_free(ctx->octx);
 127                 ssh_digest_free(ctx->digest);
 128                 if (ctx->buf) {
 129                         explicit_bzero(ctx->buf, ctx->buf_len);
 130                         free(ctx->buf);
 131                 }
 132                 explicit_bzero(ctx, sizeof(*ctx));
 133                 free(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