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