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Annotation of src/usr.bin/ssh/mac.c, Revision 1.1

1.1     ! markus      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 1.7 2001/02/08 19:30:51 itojun 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:        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 = mac->md->md_size;
        !            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: }