mac.c revision 262566
15897Sjmz/* $OpenBSD: mac.c,v 1.26 2014/01/04 17:50:55 tedu Exp $ */ 25897Sjmz/* 35897Sjmz * Copyright (c) 2001 Markus Friedl. All rights reserved. 45897Sjmz * 55897Sjmz * Redistribution and use in source and binary forms, with or without 65897Sjmz * modification, are permitted provided that the following conditions 75897Sjmz * are met: 85897Sjmz * 1. Redistributions of source code must retain the above copyright 95897Sjmz * notice, this list of conditions and the following disclaimer. 105897Sjmz * 2. Redistributions in binary form must reproduce the above copyright 115897Sjmz * notice, this list of conditions and the following disclaimer in the 125897Sjmz * documentation and/or other materials provided with the distribution. 135897Sjmz * 145897Sjmz * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 155897Sjmz * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 165897Sjmz * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 175897Sjmz * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 185897Sjmz * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 195897Sjmz * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 205897Sjmz * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 215897Sjmz * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 225897Sjmz * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 235897Sjmz * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 245897Sjmz */ 255897Sjmz 265897Sjmz#include "includes.h" 275897Sjmz 285897Sjmz#include <sys/types.h> 295897Sjmz 305897Sjmz#include <openssl/hmac.h> 315897Sjmz 325897Sjmz#include <stdarg.h> 335897Sjmz#include <string.h> 346734Sbde#include <signal.h> 357430Sbde 367430Sbde#include "xmalloc.h" 376734Sbde#include "log.h" 386734Sbde#include "cipher.h" 396734Sbde#include "buffer.h" 405897Sjmz#include "key.h" 416734Sbde#include "kex.h" 425897Sjmz#include "mac.h" 435897Sjmz#include "misc.h" 445897Sjmz 455897Sjmz#include "umac.h" 465897Sjmz 475897Sjmz#include "openbsd-compat/openssl-compat.h" 485897Sjmz 495897Sjmz#define SSH_EVP 1 /* OpenSSL EVP-based MAC */ 505897Sjmz#define SSH_UMAC 2 /* UMAC (not integrated with OpenSSL) */ 515897Sjmz#define SSH_UMAC128 3 525897Sjmz 535897Sjmzstruct macalg { 545897Sjmz char *name; 555993Sjmz int type; 565993Sjmz const EVP_MD * (*mdfunc)(void); 575998Sjmz int truncatebits; /* truncate digest if != 0 */ 585998Sjmz int key_len; /* just for UMAC */ 595897Sjmz int len; /* just for UMAC */ 605897Sjmz int etm; /* Encrypt-then-MAC */ 615897Sjmz}; 625897Sjmz 635897Sjmzstatic const struct macalg macs[] = { 645897Sjmz /* Encrypt-and-MAC (encrypt-and-authenticate) variants */ 655897Sjmz { "hmac-sha1", SSH_EVP, EVP_sha1, 0, 0, 0, 0 }, 665897Sjmz { "hmac-sha1-96", SSH_EVP, EVP_sha1, 96, 0, 0, 0 }, 675897Sjmz#ifdef HAVE_EVP_SHA256 685897Sjmz { "hmac-sha2-256", SSH_EVP, EVP_sha256, 0, 0, 0, 0 }, 695897Sjmz { "hmac-sha2-512", SSH_EVP, EVP_sha512, 0, 0, 0, 0 }, 705897Sjmz#endif 715897Sjmz { "hmac-md5", SSH_EVP, EVP_md5, 0, 0, 0, 0 }, 725897Sjmz { "hmac-md5-96", SSH_EVP, EVP_md5, 96, 0, 0, 0 }, 735897Sjmz { "hmac-ripemd160", SSH_EVP, EVP_ripemd160, 0, 0, 0, 0 }, 745993Sjmz { "hmac-ripemd160@openssh.com", SSH_EVP, EVP_ripemd160, 0, 0, 0, 0 }, 755897Sjmz { "umac-64@openssh.com", SSH_UMAC, NULL, 0, 128, 64, 0 }, 765897Sjmz { "umac-128@openssh.com", SSH_UMAC128, NULL, 0, 128, 128, 0 }, 775897Sjmz 785897Sjmz /* Encrypt-then-MAC variants */ 795897Sjmz { "hmac-sha1-etm@openssh.com", SSH_EVP, EVP_sha1, 0, 0, 0, 1 }, 805897Sjmz { "hmac-sha1-96-etm@openssh.com", SSH_EVP, EVP_sha1, 96, 0, 0, 1 }, 815897Sjmz#ifdef HAVE_EVP_SHA256 825897Sjmz { "hmac-sha2-256-etm@openssh.com", SSH_EVP, EVP_sha256, 0, 0, 0, 1 }, 835897Sjmz { "hmac-sha2-512-etm@openssh.com", SSH_EVP, EVP_sha512, 0, 0, 0, 1 }, 845897Sjmz#endif 855897Sjmz { "hmac-md5-etm@openssh.com", SSH_EVP, EVP_md5, 0, 0, 0, 1 }, 865897Sjmz { "hmac-md5-96-etm@openssh.com", SSH_EVP, EVP_md5, 96, 0, 0, 1 }, 875897Sjmz { "hmac-ripemd160-etm@openssh.com", SSH_EVP, EVP_ripemd160, 0, 0, 0, 1 }, 885897Sjmz { "umac-64-etm@openssh.com", SSH_UMAC, NULL, 0, 128, 64, 1 }, 895897Sjmz { "umac-128-etm@openssh.com", SSH_UMAC128, NULL, 0, 128, 128, 1 }, 905897Sjmz 915897Sjmz { NULL, 0, NULL, 0, 0, 0, 0 } 925897Sjmz}; 935897Sjmz 945897Sjmz/* Returns a list of supported MACs separated by the specified char. */ 955897Sjmzchar * 965897Sjmzmac_alg_list(char sep) 975897Sjmz{ 985897Sjmz char *ret = NULL; 995897Sjmz size_t nlen, rlen = 0; 1005897Sjmz const struct macalg *m; 1015897Sjmz 1025897Sjmz for (m = macs; m->name != NULL; m++) { 1035897Sjmz if (ret != NULL) 1045897Sjmz ret[rlen++] = sep; 1055897Sjmz nlen = strlen(m->name); 1065897Sjmz ret = xrealloc(ret, 1, rlen + nlen + 2); 1075897Sjmz memcpy(ret + rlen, m->name, nlen + 1); 1085897Sjmz rlen += nlen; 1095897Sjmz } 1105897Sjmz return ret; 1115897Sjmz} 1125897Sjmz 1135897Sjmzstatic void 1145897Sjmzmac_setup_by_alg(Mac *mac, const struct macalg *macalg) 1155897Sjmz{ 1165897Sjmz int evp_len; 1175897Sjmz 1185897Sjmz mac->type = macalg->type; 1195897Sjmz if (mac->type == SSH_EVP) { 1205897Sjmz mac->evp_md = macalg->mdfunc(); 1215897Sjmz if ((evp_len = EVP_MD_size(mac->evp_md)) <= 0) 1225897Sjmz fatal("mac %s len %d", mac->name, evp_len); 1235897Sjmz mac->key_len = mac->mac_len = (u_int)evp_len; 1245897Sjmz } else { 1255897Sjmz mac->mac_len = macalg->len / 8; 1265897Sjmz mac->key_len = macalg->key_len / 8; 1275897Sjmz mac->umac_ctx = NULL; 1285897Sjmz } 1295897Sjmz if (macalg->truncatebits != 0) 1305897Sjmz mac->mac_len = macalg->truncatebits / 8; 1315897Sjmz mac->etm = macalg->etm; 1325897Sjmz} 1335897Sjmz 1346644Sjmzint 1355897Sjmzmac_setup(Mac *mac, char *name) 1365897Sjmz{ 1375897Sjmz const struct macalg *m; 1385897Sjmz 1395897Sjmz for (m = macs; m->name != NULL; m++) { 1405897Sjmz if (strcmp(name, m->name) != 0) 1415897Sjmz continue; 1425897Sjmz if (mac != NULL) 1435897Sjmz mac_setup_by_alg(mac, m); 1445897Sjmz debug2("mac_setup: found %s", name); 1455897Sjmz return (0); 1465897Sjmz } 1475993Sjmz debug2("mac_setup: unknown %s", name); 1485897Sjmz return (-1); 1495897Sjmz} 1505897Sjmz 1515897Sjmzint 1525897Sjmzmac_init(Mac *mac) 1535897Sjmz{ 1545897Sjmz if (mac->key == NULL) 1555897Sjmz fatal("mac_init: no key"); 1566644Sjmz switch (mac->type) { 1576644Sjmz case SSH_EVP: 1585897Sjmz if (mac->evp_md == NULL) 1596644Sjmz return -1; 1606644Sjmz HMAC_CTX_init(&mac->evp_ctx); 1617430Sbde HMAC_Init(&mac->evp_ctx, mac->key, mac->key_len, mac->evp_md); 1625897Sjmz return 0; 1635897Sjmz case SSH_UMAC: 1645897Sjmz mac->umac_ctx = umac_new(mac->key); 1655897Sjmz return 0; 1665897Sjmz case SSH_UMAC128: 1675897Sjmz mac->umac_ctx = umac128_new(mac->key); 1685897Sjmz return 0; 1695897Sjmz default: 1705897Sjmz return -1; 1715897Sjmz } 1725897Sjmz} 1735897Sjmz 1745897Sjmzu_char * 1755897Sjmzmac_compute(Mac *mac, u_int32_t seqno, u_char *data, int datalen) 1765897Sjmz{ 1775897Sjmz static union { 1785897Sjmz u_char m[EVP_MAX_MD_SIZE]; 1795897Sjmz u_int64_t for_align; 1805897Sjmz } u; 1815897Sjmz u_char b[4], nonce[8]; 1825897Sjmz 1835897Sjmz if (mac->mac_len > sizeof(u)) 1845897Sjmz fatal("mac_compute: mac too long %u %zu", 1855897Sjmz mac->mac_len, sizeof(u)); 1865897Sjmz 1875897Sjmz switch (mac->type) { 1885897Sjmz case SSH_EVP: 1895897Sjmz put_u32(b, seqno); 1905897Sjmz /* reset HMAC context */ 1915897Sjmz HMAC_Init(&mac->evp_ctx, NULL, 0, NULL); 1925897Sjmz HMAC_Update(&mac->evp_ctx, b, sizeof(b)); 1935897Sjmz HMAC_Update(&mac->evp_ctx, data, datalen); 1945897Sjmz HMAC_Final(&mac->evp_ctx, u.m, NULL); 1955897Sjmz break; 1965897Sjmz case SSH_UMAC: 1975897Sjmz put_u64(nonce, seqno); 1985897Sjmz umac_update(mac->umac_ctx, data, datalen); 1995897Sjmz umac_final(mac->umac_ctx, u.m, nonce); 2005897Sjmz break; 2015897Sjmz case SSH_UMAC128: 2025897Sjmz put_u64(nonce, seqno); 2035897Sjmz umac128_update(mac->umac_ctx, data, datalen); 2045897Sjmz umac128_final(mac->umac_ctx, u.m, nonce); 2055897Sjmz break; 2065897Sjmz default: 2075897Sjmz fatal("mac_compute: unknown MAC type"); 2085897Sjmz } 209 return (u.m); 210} 211 212void 213mac_clear(Mac *mac) 214{ 215 if (mac->type == SSH_UMAC) { 216 if (mac->umac_ctx != NULL) 217 umac_delete(mac->umac_ctx); 218 } else if (mac->type == SSH_UMAC128) { 219 if (mac->umac_ctx != NULL) 220 umac128_delete(mac->umac_ctx); 221 } else if (mac->evp_md != NULL) 222 HMAC_cleanup(&mac->evp_ctx); 223 mac->evp_md = NULL; 224 mac->umac_ctx = NULL; 225} 226 227/* XXX copied from ciphers_valid */ 228#define MAC_SEP "," 229int 230mac_valid(const char *names) 231{ 232 char *maclist, *cp, *p; 233 234 if (names == NULL || strcmp(names, "") == 0) 235 return (0); 236 maclist = cp = xstrdup(names); 237 for ((p = strsep(&cp, MAC_SEP)); p && *p != '\0'; 238 (p = strsep(&cp, MAC_SEP))) { 239 if (mac_setup(NULL, p) < 0) { 240 debug("bad mac %s [%s]", p, names); 241 free(maclist); 242 return (0); 243 } else { 244 debug3("mac ok: %s [%s]", p, names); 245 } 246 } 247 debug3("macs ok: [%s]", names); 248 free(maclist); 249 return (1); 250} 251