1 /* 2 * Copyright (c) 2001 Markus Friedl. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 14 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 15 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 16 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 17 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 18 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 19 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 20 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 22 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 23 */ 24 25 #include "includes.h" 26 RCSID("$OpenBSD: mac.c,v 1.5 2002/05/16 22:02:50 markus Exp $"); 27 28 #include <openssl/hmac.h> 29 30 #include "xmalloc.h" 31 #include "getput.h" 32 #include "log.h" 33 #include "cipher.h" 34 #include "kex.h" 35 #include "mac.h" 36 37 struct { 38 char *name; 39 const EVP_MD * (*mdfunc)(void); 40 int truncatebits; /* truncate digest if != 0 */ 41 } macs[] = { 42 { "hmac-sha1", EVP_sha1, 0, }, 43 { "hmac-sha1-96", EVP_sha1, 96 }, 44 { "hmac-md5", EVP_md5, 0 }, 45 { "hmac-md5-96", EVP_md5, 96 }, 46 { "hmac-ripemd160", EVP_ripemd160, 0 }, 47 { "hmac-ripemd160@openssh.com", EVP_ripemd160, 0 }, 48 { NULL, NULL, 0 } 49 }; 50 51 int 52 mac_init(Mac *mac, char *name) 53 { 54 int i; 55 for (i = 0; macs[i].name; i++) { 56 if (strcmp(name, macs[i].name) == 0) { 57 if (mac != NULL) { 58 mac->md = (*macs[i].mdfunc)(); 59 mac->key_len = mac->mac_len = EVP_MD_size(mac->md); 60 if (macs[i].truncatebits != 0) 61 mac->mac_len = macs[i].truncatebits/8; 62 } 63 debug2("mac_init: found %s", name); 64 return (0); 65 } 66 } 67 debug2("mac_init: unknown %s", name); 68 return (-1); 69 } 70 71 u_char * 72 mac_compute(Mac *mac, u_int32_t seqno, u_char *data, int datalen) 73 { 74 HMAC_CTX c; 75 static u_char m[EVP_MAX_MD_SIZE]; 76 u_char b[4]; 77 78 if (mac->key == NULL) 79 fatal("mac_compute: no key"); 80 if (mac->mac_len > sizeof(m)) 81 fatal("mac_compute: mac too long"); 82 HMAC_Init(&c, mac->key, mac->key_len, mac->md); 83 PUT_32BIT(b, seqno); 84 HMAC_Update(&c, b, sizeof(b)); 85 HMAC_Update(&c, data, datalen); 86 HMAC_Final(&c, m, NULL); 87 HMAC_cleanup(&c); 88 return (m); 89 } 90 91 /* XXX copied from ciphers_valid */ 92 #define MAC_SEP "," 93 int 94 mac_valid(const char *names) 95 { 96 char *maclist, *cp, *p; 97 98 if (names == NULL || strcmp(names, "") == 0) 99 return (0); 100 maclist = cp = xstrdup(names); 101 for ((p = strsep(&cp, MAC_SEP)); p && *p != '\0'; 102 (p = strsep(&cp, MAC_SEP))) { 103 if (mac_init(NULL, p) < 0) { 104 debug("bad mac %s [%s]", p, names); 105 xfree(maclist); 106 return (0); 107 } else { 108 debug3("mac ok: %s [%s]", p, names); 109 } 110 } 111 debug3("macs ok: [%s]", names); 112 xfree(maclist); 113 return (1); 114 } 115