Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 1 | /* $OpenBSD: mac.c,v 1.32 2015/01/15 18:32:54 naddy Exp $ */ |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 2 | /* |
| 3 | * Copyright (c) 2001 Markus Friedl. All rights reserved. |
| 4 | * |
| 5 | * Redistribution and use in source and binary forms, with or without |
| 6 | * modification, are permitted provided that the following conditions |
| 7 | * are met: |
| 8 | * 1. Redistributions of source code must retain the above copyright |
| 9 | * notice, this list of conditions and the following disclaimer. |
| 10 | * 2. Redistributions in binary form must reproduce the above copyright |
| 11 | * notice, this list of conditions and the following disclaimer in the |
| 12 | * documentation and/or other materials provided with the distribution. |
| 13 | * |
| 14 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| 15 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 16 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| 17 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| 18 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| 19 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 20 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 21 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 22 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| 23 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 24 | */ |
| 25 | |
| 26 | #include "includes.h" |
| 27 | |
| 28 | #include <sys/types.h> |
| 29 | |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 30 | #include <string.h> |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 31 | #include <stdio.h> |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 32 | |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 33 | #include "digest.h" |
| 34 | #include "hmac.h" |
| 35 | #include "umac.h" |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 36 | #include "mac.h" |
| 37 | #include "misc.h" |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 38 | #include "ssherr.h" |
| 39 | #include "sshbuf.h" |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 40 | |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 41 | #include "openbsd-compat/openssl-compat.h" |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 42 | |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 43 | #define SSH_DIGEST 1 /* SSH_DIGEST_XXX */ |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 44 | #define SSH_UMAC 2 /* UMAC (not integrated with OpenSSL) */ |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 45 | #define SSH_UMAC128 3 |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 46 | |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 47 | struct macalg { |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 48 | char *name; |
| 49 | int type; |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 50 | int alg; |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 51 | int truncatebits; /* truncate digest if != 0 */ |
| 52 | int key_len; /* just for UMAC */ |
| 53 | int len; /* just for UMAC */ |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 54 | int etm; /* Encrypt-then-MAC */ |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 55 | }; |
| 56 | |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 57 | static const struct macalg macs[] = { |
| 58 | /* Encrypt-and-MAC (encrypt-and-authenticate) variants */ |
| 59 | { "hmac-sha1", SSH_DIGEST, SSH_DIGEST_SHA1, 0, 0, 0, 0 }, |
| 60 | { "hmac-sha1-96", SSH_DIGEST, SSH_DIGEST_SHA1, 96, 0, 0, 0 }, |
| 61 | #ifdef HAVE_EVP_SHA256 |
| 62 | { "hmac-sha2-256", SSH_DIGEST, SSH_DIGEST_SHA256, 0, 0, 0, 0 }, |
| 63 | { "hmac-sha2-512", SSH_DIGEST, SSH_DIGEST_SHA512, 0, 0, 0, 0 }, |
| 64 | #endif |
| 65 | { "hmac-md5", SSH_DIGEST, SSH_DIGEST_MD5, 0, 0, 0, 0 }, |
| 66 | { "hmac-md5-96", SSH_DIGEST, SSH_DIGEST_MD5, 96, 0, 0, 0 }, |
| 67 | #if defined(HAVE_EVP_RIPEMD) |
| 68 | { "hmac-ripemd160", SSH_DIGEST, SSH_DIGEST_RIPEMD160, 0, 0, 0, 0 }, |
| 69 | { "hmac-ripemd160@openssh.com", SSH_DIGEST, SSH_DIGEST_RIPEMD160, 0, 0, 0, 0 }, |
| 70 | #endif |
| 71 | { "umac-64@openssh.com", SSH_UMAC, 0, 0, 128, 64, 0 }, |
| 72 | { "umac-128@openssh.com", SSH_UMAC128, 0, 0, 128, 128, 0 }, |
| 73 | |
| 74 | /* Encrypt-then-MAC variants */ |
| 75 | { "hmac-sha1-etm@openssh.com", SSH_DIGEST, SSH_DIGEST_SHA1, 0, 0, 0, 1 }, |
| 76 | { "hmac-sha1-96-etm@openssh.com", SSH_DIGEST, SSH_DIGEST_SHA1, 96, 0, 0, 1 }, |
| 77 | #ifdef HAVE_EVP_SHA256 |
| 78 | { "hmac-sha2-256-etm@openssh.com", SSH_DIGEST, SSH_DIGEST_SHA256, 0, 0, 0, 1 }, |
| 79 | { "hmac-sha2-512-etm@openssh.com", SSH_DIGEST, SSH_DIGEST_SHA512, 0, 0, 0, 1 }, |
| 80 | #endif |
| 81 | { "hmac-md5-etm@openssh.com", SSH_DIGEST, SSH_DIGEST_MD5, 0, 0, 0, 1 }, |
| 82 | { "hmac-md5-96-etm@openssh.com", SSH_DIGEST, SSH_DIGEST_MD5, 96, 0, 0, 1 }, |
| 83 | { "hmac-ripemd160-etm@openssh.com", SSH_DIGEST, SSH_DIGEST_RIPEMD160, 0, 0, 0, 1 }, |
| 84 | { "umac-64-etm@openssh.com", SSH_UMAC, 0, 0, 128, 64, 1 }, |
| 85 | { "umac-128-etm@openssh.com", SSH_UMAC128, 0, 0, 128, 128, 1 }, |
| 86 | |
| 87 | { NULL, 0, 0, 0, 0, 0, 0 } |
| 88 | }; |
| 89 | |
| 90 | /* Returns a list of supported MACs separated by the specified char. */ |
| 91 | char * |
| 92 | mac_alg_list(char sep) |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 93 | { |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 94 | char *ret = NULL, *tmp; |
| 95 | size_t nlen, rlen = 0; |
| 96 | const struct macalg *m; |
| 97 | |
| 98 | for (m = macs; m->name != NULL; m++) { |
| 99 | if (ret != NULL) |
| 100 | ret[rlen++] = sep; |
| 101 | nlen = strlen(m->name); |
| 102 | if ((tmp = realloc(ret, rlen + nlen + 2)) == NULL) { |
| 103 | free(ret); |
| 104 | return NULL; |
| 105 | } |
| 106 | ret = tmp; |
| 107 | memcpy(ret + rlen, m->name, nlen + 1); |
| 108 | rlen += nlen; |
| 109 | } |
| 110 | return ret; |
| 111 | } |
| 112 | |
| 113 | static int |
| 114 | mac_setup_by_alg(struct sshmac *mac, const struct macalg *macalg) |
| 115 | { |
| 116 | mac->type = macalg->type; |
| 117 | if (mac->type == SSH_DIGEST) { |
| 118 | if ((mac->hmac_ctx = ssh_hmac_start(macalg->alg)) == NULL) |
| 119 | return SSH_ERR_ALLOC_FAIL; |
| 120 | mac->key_len = mac->mac_len = ssh_hmac_bytes(macalg->alg); |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 121 | } else { |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 122 | mac->mac_len = macalg->len / 8; |
| 123 | mac->key_len = macalg->key_len / 8; |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 124 | mac->umac_ctx = NULL; |
| 125 | } |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 126 | if (macalg->truncatebits != 0) |
| 127 | mac->mac_len = macalg->truncatebits / 8; |
| 128 | mac->etm = macalg->etm; |
| 129 | return 0; |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 130 | } |
| 131 | |
| 132 | int |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 133 | mac_setup(struct sshmac *mac, char *name) |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 134 | { |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 135 | const struct macalg *m; |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 136 | |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 137 | for (m = macs; m->name != NULL; m++) { |
| 138 | if (strcmp(name, m->name) != 0) |
| 139 | continue; |
| 140 | if (mac != NULL) |
| 141 | return mac_setup_by_alg(mac, m); |
| 142 | return 0; |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 143 | } |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 144 | return SSH_ERR_INVALID_ARGUMENT; |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 145 | } |
| 146 | |
| 147 | int |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 148 | mac_init(struct sshmac *mac) |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 149 | { |
| 150 | if (mac->key == NULL) |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 151 | return SSH_ERR_INVALID_ARGUMENT; |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 152 | switch (mac->type) { |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 153 | case SSH_DIGEST: |
| 154 | if (mac->hmac_ctx == NULL || |
| 155 | ssh_hmac_init(mac->hmac_ctx, mac->key, mac->key_len) < 0) |
| 156 | return SSH_ERR_INVALID_ARGUMENT; |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 157 | return 0; |
| 158 | case SSH_UMAC: |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 159 | if ((mac->umac_ctx = umac_new(mac->key)) == NULL) |
| 160 | return SSH_ERR_ALLOC_FAIL; |
| 161 | return 0; |
| 162 | case SSH_UMAC128: |
| 163 | if ((mac->umac_ctx = umac128_new(mac->key)) == NULL) |
| 164 | return SSH_ERR_ALLOC_FAIL; |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 165 | return 0; |
| 166 | default: |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 167 | return SSH_ERR_INVALID_ARGUMENT; |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 168 | } |
| 169 | } |
| 170 | |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 171 | int |
| 172 | mac_compute(struct sshmac *mac, u_int32_t seqno, const u_char *data, int datalen, |
| 173 | u_char *digest, size_t dlen) |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 174 | { |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 175 | static union { |
| 176 | u_char m[SSH_DIGEST_MAX_LENGTH]; |
| 177 | u_int64_t for_align; |
| 178 | } u; |
| 179 | u_char b[4]; |
| 180 | u_char nonce[8]; |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 181 | |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 182 | if (mac->mac_len > sizeof(u)) |
| 183 | return SSH_ERR_INTERNAL_ERROR; |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 184 | |
| 185 | switch (mac->type) { |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 186 | case SSH_DIGEST: |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 187 | put_u32(b, seqno); |
| 188 | /* reset HMAC context */ |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 189 | if (ssh_hmac_init(mac->hmac_ctx, NULL, 0) < 0 || |
| 190 | ssh_hmac_update(mac->hmac_ctx, b, sizeof(b)) < 0 || |
| 191 | ssh_hmac_update(mac->hmac_ctx, data, datalen) < 0 || |
| 192 | ssh_hmac_final(mac->hmac_ctx, u.m, sizeof(u.m)) < 0) |
| 193 | return SSH_ERR_LIBCRYPTO_ERROR; |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 194 | break; |
| 195 | case SSH_UMAC: |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 196 | POKE_U64(nonce, seqno); |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 197 | umac_update(mac->umac_ctx, data, datalen); |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 198 | umac_final(mac->umac_ctx, u.m, nonce); |
| 199 | break; |
| 200 | case SSH_UMAC128: |
| 201 | put_u64(nonce, seqno); |
| 202 | umac128_update(mac->umac_ctx, data, datalen); |
| 203 | umac128_final(mac->umac_ctx, u.m, nonce); |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 204 | break; |
| 205 | default: |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 206 | return SSH_ERR_INVALID_ARGUMENT; |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 207 | } |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 208 | if (digest != NULL) { |
| 209 | if (dlen > mac->mac_len) |
| 210 | dlen = mac->mac_len; |
| 211 | memcpy(digest, u.m, dlen); |
| 212 | } |
| 213 | return 0; |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 214 | } |
| 215 | |
| 216 | void |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 217 | mac_clear(struct sshmac *mac) |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 218 | { |
| 219 | if (mac->type == SSH_UMAC) { |
| 220 | if (mac->umac_ctx != NULL) |
| 221 | umac_delete(mac->umac_ctx); |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 222 | } else if (mac->type == SSH_UMAC128) { |
| 223 | if (mac->umac_ctx != NULL) |
| 224 | umac128_delete(mac->umac_ctx); |
| 225 | } else if (mac->hmac_ctx != NULL) |
| 226 | ssh_hmac_free(mac->hmac_ctx); |
| 227 | mac->hmac_ctx = NULL; |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 228 | mac->umac_ctx = NULL; |
| 229 | } |
| 230 | |
| 231 | /* XXX copied from ciphers_valid */ |
| 232 | #define MAC_SEP "," |
| 233 | int |
| 234 | mac_valid(const char *names) |
| 235 | { |
| 236 | char *maclist, *cp, *p; |
| 237 | |
| 238 | if (names == NULL || strcmp(names, "") == 0) |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 239 | return 0; |
| 240 | if ((maclist = cp = strdup(names)) == NULL) |
| 241 | return 0; |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 242 | for ((p = strsep(&cp, MAC_SEP)); p && *p != '\0'; |
| 243 | (p = strsep(&cp, MAC_SEP))) { |
| 244 | if (mac_setup(NULL, p) < 0) { |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 245 | free(maclist); |
| 246 | return 0; |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 247 | } |
| 248 | } |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 249 | free(maclist); |
| 250 | return 1; |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 251 | } |