mac.c revision 248619
177957Sbenno/* $OpenBSD: mac.c,v 1.21 2012/12/11 22:51:45 sthen Exp $ */ 277957Sbenno/* 377957Sbenno * Copyright (c) 2001 Markus Friedl. All rights reserved. 4139825Simp * 577957Sbenno * Redistribution and use in source and binary forms, with or without 677957Sbenno * modification, are permitted provided that the following conditions 777957Sbenno * are met: 877957Sbenno * 1. Redistributions of source code must retain the above copyright 977957Sbenno * notice, this list of conditions and the following disclaimer. 1077957Sbenno * 2. Redistributions in binary form must reproduce the above copyright 1177957Sbenno * notice, this list of conditions and the following disclaimer in the 1277957Sbenno * documentation and/or other materials provided with the distribution. 1377957Sbenno * 1477957Sbenno * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 1577957Sbenno * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 1677957Sbenno * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 1777957Sbenno * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 1877957Sbenno * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 1977957Sbenno * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 2077957Sbenno * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 2177957Sbenno * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 2277957Sbenno * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 2377957Sbenno * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 2477957Sbenno */ 2577957Sbenno 2677957Sbenno#include "includes.h" 2777957Sbenno 28139825Simp#include <sys/types.h> 2977957Sbenno 3077957Sbenno#include <openssl/hmac.h> 3177957Sbenno 3277957Sbenno#include <stdarg.h> 3377957Sbenno#include <string.h> 3477957Sbenno#include <signal.h> 3577957Sbenno 3677957Sbenno#include "xmalloc.h" 3777957Sbenno#include "log.h" 3877957Sbenno#include "cipher.h" 3977957Sbenno#include "buffer.h" 4077957Sbenno#include "key.h" 4177957Sbenno#include "kex.h" 4277957Sbenno#include "mac.h" 4377957Sbenno#include "misc.h" 4477957Sbenno 4577957Sbenno#include "umac.h" 4677957Sbenno 4777957Sbenno#include "openbsd-compat/openssl-compat.h" 4877957Sbenno 4977957Sbenno#define SSH_EVP 1 /* OpenSSL EVP-based MAC */ 5077957Sbenno#define SSH_UMAC 2 /* UMAC (not integrated with OpenSSL) */ 5177957Sbenno#define SSH_UMAC128 3 5277957Sbenno 5377957Sbennostruct { 5477957Sbenno char *name; 5577957Sbenno int type; 5677957Sbenno const EVP_MD * (*mdfunc)(void); 5777957Sbenno int truncatebits; /* truncate digest if != 0 */ 5877957Sbenno int key_len; /* just for UMAC */ 5977957Sbenno int len; /* just for UMAC */ 60198723Snwhitehorn int etm; /* Encrypt-then-MAC */ 6177957Sbenno} macs[] = { 6277957Sbenno /* Encrypt-and-MAC (encrypt-and-authenticate) variants */ 6377957Sbenno { "hmac-sha1", SSH_EVP, EVP_sha1, 0, 0, 0, 0 }, 6477957Sbenno { "hmac-sha1-96", SSH_EVP, EVP_sha1, 96, 0, 0, 0 }, 6577957Sbenno#ifdef HAVE_EVP_SHA256 6677957Sbenno { "hmac-sha2-256", SSH_EVP, EVP_sha256, 0, 0, 0, 0 }, 6777957Sbenno { "hmac-sha2-512", SSH_EVP, EVP_sha512, 0, 0, 0, 0 }, 6877957Sbenno#endif 69178628Smarcel { "hmac-md5", SSH_EVP, EVP_md5, 0, 0, 0, 0 }, 70178628Smarcel { "hmac-md5-96", SSH_EVP, EVP_md5, 96, 0, 0, 0 }, 71231019Sandreast { "hmac-ripemd160", SSH_EVP, EVP_ripemd160, 0, 0, 0, 0 }, 72223485Snwhitehorn { "hmac-ripemd160@openssh.com", SSH_EVP, EVP_ripemd160, 0, 0, 0, 0 }, 73178628Smarcel { "umac-64@openssh.com", SSH_UMAC, NULL, 0, 128, 64, 0 }, 74178628Smarcel { "umac-128@openssh.com", SSH_UMAC128, NULL, 0, 128, 128, 0 }, 75178628Smarcel 76172887Sgrehan /* Encrypt-then-MAC variants */ 77172887Sgrehan { "hmac-sha1-etm@openssh.com", SSH_EVP, EVP_sha1, 0, 0, 0, 1 }, 78172887Sgrehan { "hmac-sha1-96-etm@openssh.com", SSH_EVP, EVP_sha1, 96, 0, 0, 1 }, 79118893Sgrehan#ifdef HAVE_EVP_SHA256 80118893Sgrehan { "hmac-sha2-256-etm@openssh.com", SSH_EVP, EVP_sha256, 0, 0, 0, 1 }, 8177957Sbenno { "hmac-sha2-512-etm@openssh.com", SSH_EVP, EVP_sha512, 0, 0, 0, 1 }, 82231019Sandreast#endif 83209975Snwhitehorn { "hmac-md5-etm@openssh.com", SSH_EVP, EVP_md5, 0, 0, 0, 1 }, 84209975Snwhitehorn { "hmac-md5-96-etm@openssh.com", SSH_EVP, EVP_md5, 96, 0, 0, 1 }, 85118893Sgrehan { "hmac-ripemd160-etm@openssh.com", SSH_EVP, EVP_ripemd160, 0, 0, 0, 1 }, 86209975Snwhitehorn { "umac-64-etm@openssh.com", SSH_UMAC, NULL, 0, 128, 64, 1 }, 87209975Snwhitehorn { "umac-128-etm@openssh.com", SSH_UMAC128, NULL, 0, 128, 128, 1 }, 88209975Snwhitehorn 89209975Snwhitehorn { NULL, 0, NULL, 0, 0, 0, 0 } 90209975Snwhitehorn}; 91209975Snwhitehorn 92209975Snwhitehornstatic void 93209975Snwhitehornmac_setup_by_id(Mac *mac, int which) 94209975Snwhitehorn{ 95209975Snwhitehorn int evp_len; 96209975Snwhitehorn mac->type = macs[which].type; 97209975Snwhitehorn if (mac->type == SSH_EVP) { 98209975Snwhitehorn mac->evp_md = (*macs[which].mdfunc)(); 99209975Snwhitehorn if ((evp_len = EVP_MD_size(mac->evp_md)) <= 0) 100209975Snwhitehorn fatal("mac %s len %d", mac->name, evp_len); 101209975Snwhitehorn mac->key_len = mac->mac_len = (u_int)evp_len; 102209975Snwhitehorn } else { 103209975Snwhitehorn mac->mac_len = macs[which].len / 8; 104118893Sgrehan mac->key_len = macs[which].key_len / 8; 10591486Sbenno mac->umac_ctx = NULL; 106209975Snwhitehorn } 10791486Sbenno if (macs[which].truncatebits != 0) 108209975Snwhitehorn mac->mac_len = macs[which].truncatebits / 8; 109209975Snwhitehorn mac->etm = macs[which].etm; 110209975Snwhitehorn} 111209975Snwhitehorn 112118893Sgrehanint 113223485Snwhitehornmac_setup(Mac *mac, char *name) 114198723Snwhitehorn{ 115198731Snwhitehorn int i; 116118893Sgrehan 117209975Snwhitehorn for (i = 0; macs[i].name; i++) { 118209975Snwhitehorn if (strcmp(name, macs[i].name) == 0) { 119198731Snwhitehorn if (mac != NULL) 120178628Smarcel mac_setup_by_id(mac, i); 121198731Snwhitehorn debug2("mac_setup: found %s", name); 12286066Smp return (0); 123218824Snwhitehorn } 124209975Snwhitehorn } 125188860Snwhitehorn debug2("mac_setup: unknown %s", name); 126188860Snwhitehorn return (-1); 127198731Snwhitehorn} 128198731Snwhitehorn 129188860Snwhitehornint 130198731Snwhitehornmac_init(Mac *mac) 131188860Snwhitehorn{ 132218824Snwhitehorn if (mac->key == NULL) 133209975Snwhitehorn fatal("mac_init: no key"); 134188860Snwhitehorn switch (mac->type) { 135188860Snwhitehorn case SSH_EVP: 136118893Sgrehan if (mac->evp_md == NULL) 137218824Snwhitehorn return -1; 138209975Snwhitehorn HMAC_CTX_init(&mac->evp_ctx); 13991486Sbenno HMAC_Init(&mac->evp_ctx, mac->key, mac->key_len, mac->evp_md); 140209975Snwhitehorn return 0; 141198723Snwhitehorn case SSH_UMAC: 142234517Snwhitehorn mac->umac_ctx = umac_new(mac->key); 143209975Snwhitehorn return 0; 144209975Snwhitehorn case SSH_UMAC128: 145178628Smarcel mac->umac_ctx = umac128_new(mac->key); 146198723Snwhitehorn return 0; 147198723Snwhitehorn default: 148198723Snwhitehorn return -1; 149198723Snwhitehorn } 150198723Snwhitehorn} 151223485Snwhitehorn 152209975Snwhitehornu_char * 153235013Snwhitehornmac_compute(Mac *mac, u_int32_t seqno, u_char *data, int datalen) 154235013Snwhitehorn{ 155198723Snwhitehorn static u_char m[EVP_MAX_MD_SIZE]; 156198723Snwhitehorn u_char b[4], nonce[8]; 157118893Sgrehan 158223485Snwhitehorn if (mac->mac_len > sizeof(m)) 159223485Snwhitehorn fatal("mac_compute: mac too long %u %lu", 160209975Snwhitehorn mac->mac_len, (u_long)sizeof(m)); 16177957Sbenno 162209975Snwhitehorn switch (mac->type) { 163209975Snwhitehorn case SSH_EVP: 164223485Snwhitehorn put_u32(b, seqno); 165218824Snwhitehorn /* reset HMAC context */ 166209975Snwhitehorn HMAC_Init(&mac->evp_ctx, NULL, 0, NULL); 167183088Smarcel HMAC_Update(&mac->evp_ctx, b, sizeof(b)); 168178628Smarcel HMAC_Update(&mac->evp_ctx, data, datalen); 169178628Smarcel HMAC_Final(&mac->evp_ctx, m, NULL); 170118893Sgrehan break; 171188860Snwhitehorn case SSH_UMAC: 172223485Snwhitehorn put_u64(nonce, seqno); 173218824Snwhitehorn umac_update(mac->umac_ctx, data, datalen); 174209975Snwhitehorn umac_final(mac->umac_ctx, m, nonce); 17586066Smp break; 176188860Snwhitehorn case SSH_UMAC128: 177188860Snwhitehorn put_u64(nonce, seqno); 178188860Snwhitehorn umac128_update(mac->umac_ctx, data, datalen); 179188860Snwhitehorn umac128_final(mac->umac_ctx, m, nonce); 180188860Snwhitehorn break; 181223485Snwhitehorn default: 182218824Snwhitehorn fatal("mac_compute: unknown MAC type"); 183209975Snwhitehorn } 184188860Snwhitehorn return (m); 18599036Sbenno} 186188860Snwhitehorn 187209975Snwhitehornvoid 188118893Sgrehanmac_clear(Mac *mac) 189209975Snwhitehorn{ 190209975Snwhitehorn if (mac->type == SSH_UMAC) { 191209975Snwhitehorn if (mac->umac_ctx != NULL) 192209975Snwhitehorn umac_delete(mac->umac_ctx); 193209975Snwhitehorn } else if (mac->type == SSH_UMAC128) { 194209975Snwhitehorn if (mac->umac_ctx != NULL) 195209975Snwhitehorn umac128_delete(mac->umac_ctx); 196209975Snwhitehorn } else if (mac->evp_md != NULL) 197209975Snwhitehorn HMAC_cleanup(&mac->evp_ctx); 198209975Snwhitehorn mac->evp_md = NULL; 199209975Snwhitehorn mac->umac_ctx = NULL; 200209975Snwhitehorn} 201209975Snwhitehorn 202209975Snwhitehorn/* XXX copied from ciphers_valid */ 203209975Snwhitehorn#define MAC_SEP "," 204209975Snwhitehornint 205209975Snwhitehornmac_valid(const char *names) 206209975Snwhitehorn{ 207209975Snwhitehorn char *maclist, *cp, *p; 208209975Snwhitehorn 20984945Smp if (names == NULL || strcmp(names, "") == 0) 210209975Snwhitehorn return (0); 21191486Sbenno maclist = cp = xstrdup(names); 212209975Snwhitehorn for ((p = strsep(&cp, MAC_SEP)); p && *p != '\0'; 213209975Snwhitehorn (p = strsep(&cp, MAC_SEP))) { 214209975Snwhitehorn if (mac_setup(NULL, p) < 0) { 215214574Snwhitehorn debug("bad mac %s [%s]", p, names); 216209975Snwhitehorn xfree(maclist); 217209975Snwhitehorn return (0); 218209975Snwhitehorn } else { 219214607Snwhitehorn debug3("mac ok: %s [%s]", p, names); 220209975Snwhitehorn } 221214574Snwhitehorn } 222214574Snwhitehorn debug3("macs ok: [%s]", names); 223214574Snwhitehorn xfree(maclist); 224214574Snwhitehorn return (1); 225214574Snwhitehorn} 226209975Snwhitehorn