openssl/ssl/d1_srtp.c

/* ssl/t1_lib.c */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */
/* ====================================================================
 * Copyright (c) 1998-2006 The OpenSSL Project.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    openssl-core@openssl.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 *
 * This product includes cryptographic software written by Eric Young
 * (eay@cryptsoft.com).  This product includes software written by Tim
 * Hudson (tjh@cryptsoft.com).
 *
 */
/*
 * DTLS code by Eric Rescorla <ekr@rtfm.com>
 *
 * Copyright (C) 2006, Network Resonance, Inc. Copyright (C) 2011, RTFM, Inc.
 */

#include <stdio.h>
#include <openssl/objects.h>
#include "ssl_locl.h"

#ifndef OPENSSL_NO_SRTP

static SRTP_PROTECTION_PROFILE srtp_known_profiles[] = {
    {
     "SRTP_AES128_CM_SHA1_80",
     SRTP_AES128_CM_SHA1_80,
     },
    {
     "SRTP_AES128_CM_SHA1_32",
     SRTP_AES128_CM_SHA1_32,
     },
    {0}
};

static int find_profile_by_name(char *profile_name,
                                SRTP_PROTECTION_PROFILE **pptr, unsigned len)
{
    SRTP_PROTECTION_PROFILE *p;

    p = srtp_known_profiles;
    while (p->name) {
        if ((len == strlen(p->name)) && !strncmp(p->name, profile_name, len)) {
            *pptr = p;
            return 0;
        }

        p++;
    }

    return 1;
}

static int ssl_ctx_make_profiles(const char *profiles_string,
                                 STACK_OF(SRTP_PROTECTION_PROFILE) **out)
{
    STACK_OF(SRTP_PROTECTION_PROFILE) *profiles;

    char *col;
    char *ptr = (char *)profiles_string;

    SRTP_PROTECTION_PROFILE *p;

    if (!(profiles = sk_SRTP_PROTECTION_PROFILE_new_null())) {
        SSLerr(SSL_F_SSL_CTX_MAKE_PROFILES,
               SSL_R_SRTP_COULD_NOT_ALLOCATE_PROFILES);
        return 1;
    }

    do {
        col = strchr(ptr, ':');

        if (!find_profile_by_name(ptr, &p,
                                  col ? col - ptr : (int)strlen(ptr))) {
            if (sk_SRTP_PROTECTION_PROFILE_find(profiles, p) >= 0) {
                SSLerr(SSL_F_SSL_CTX_MAKE_PROFILES,
                       SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
                sk_SRTP_PROTECTION_PROFILE_free(profiles);
                return 1;
            }

            sk_SRTP_PROTECTION_PROFILE_push(profiles, p);
        } else {
            SSLerr(SSL_F_SSL_CTX_MAKE_PROFILES,
                   SSL_R_SRTP_UNKNOWN_PROTECTION_PROFILE);
            sk_SRTP_PROTECTION_PROFILE_free(profiles);
            return 1;
        }

        if (col)
            ptr = col + 1;
    } while (col);

    *out = profiles;

    return 0;
}

int SSL_CTX_set_tlsext_use_srtp(SSL_CTX *ctx, const char *profiles)
{
    return ssl_ctx_make_profiles(profiles, &ctx->srtp_profiles);
}

int SSL_set_tlsext_use_srtp(SSL *s, const char *profiles)
{
    return ssl_ctx_make_profiles(profiles, &s->srtp_profiles);
}

STACK_OF(SRTP_PROTECTION_PROFILE) *SSL_get_srtp_profiles(SSL *s)
{
    if (s != NULL) {
        if (s->srtp_profiles != NULL) {
            return s->srtp_profiles;
        } else if ((s->ctx != NULL) && (s->ctx->srtp_profiles != NULL)) {
            return s->ctx->srtp_profiles;
        }
    }

    return NULL;
}

SRTP_PROTECTION_PROFILE *SSL_get_selected_srtp_profile(SSL *s)
{
    return s->srtp_profile;
}

/*
 * Note: this function returns 0 length if there are no profiles specified
 */
int ssl_add_clienthello_use_srtp_ext(SSL *s, unsigned char *p, int *len,
                                     int maxlen)
{
    int ct = 0;
    int i;
    STACK_OF(SRTP_PROTECTION_PROFILE) *clnt = 0;
    SRTP_PROTECTION_PROFILE *prof;

    clnt = SSL_get_srtp_profiles(s);
    ct = sk_SRTP_PROTECTION_PROFILE_num(clnt); /* -1 if clnt == 0 */

    if (p) {
        if (ct == 0) {
            SSLerr(SSL_F_SSL_ADD_CLIENTHELLO_USE_SRTP_EXT,
                   SSL_R_EMPTY_SRTP_PROTECTION_PROFILE_LIST);
            return 1;
        }

        if ((2 + ct * 2 + 1) > maxlen) {
            SSLerr(SSL_F_SSL_ADD_CLIENTHELLO_USE_SRTP_EXT,
                   SSL_R_SRTP_PROTECTION_PROFILE_LIST_TOO_LONG);
            return 1;
        }

        /* Add the length */
        s2n(ct * 2, p);
        for (i = 0; i < ct; i++) {
            prof = sk_SRTP_PROTECTION_PROFILE_value(clnt, i);
            s2n(prof->id, p);
        }

        /* Add an empty use_mki value */
        *p++ = 0;
    }

    *len = 2 + ct * 2 + 1;

    return 0;
}

int ssl_parse_clienthello_use_srtp_ext(SSL *s, unsigned char *d, int len,
                                       int *al)
{
    SRTP_PROTECTION_PROFILE *sprof;
    STACK_OF(SRTP_PROTECTION_PROFILE) *srvr;
    int ct;
    int mki_len;
    int i, srtp_pref;
    unsigned int id;

    /* Length value + the MKI length */
    if (len < 3) {
        SSLerr(SSL_F_SSL_PARSE_CLIENTHELLO_USE_SRTP_EXT,
               SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
        *al = SSL_AD_DECODE_ERROR;
        return 1;
    }

    /* Pull off the length of the cipher suite list */
    n2s(d, ct);
    len -= 2;

    /* Check that it is even */
    if (ct % 2) {
        SSLerr(SSL_F_SSL_PARSE_CLIENTHELLO_USE_SRTP_EXT,
               SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
        *al = SSL_AD_DECODE_ERROR;
        return 1;
    }

    /* Check that lengths are consistent */
    if (len < (ct + 1)) {
        SSLerr(SSL_F_SSL_PARSE_CLIENTHELLO_USE_SRTP_EXT,
               SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
        *al = SSL_AD_DECODE_ERROR;
        return 1;
    }

    srvr = SSL_get_srtp_profiles(s);
    s->srtp_profile = NULL;
    /* Search all profiles for a match initially */
    srtp_pref = sk_SRTP_PROTECTION_PROFILE_num(srvr);

    while (ct) {
        n2s(d, id);
        ct -= 2;
        len -= 2;

        /*
         * Only look for match in profiles of higher preference than
         * current match.
         * If no profiles have been have been configured then this
         * does nothing.
         */
        for (i = 0; i < srtp_pref; i++) {
            sprof = sk_SRTP_PROTECTION_PROFILE_value(srvr, i);
            if (sprof->id == id) {
                s->srtp_profile = sprof;
                srtp_pref = i;
                break;
            }
        }
    }

    /*
     * Now extract the MKI value as a sanity check, but discard it for now
     */
    mki_len = *d;
    d++;
    len--;

    if (mki_len != len) {
        SSLerr(SSL_F_SSL_PARSE_CLIENTHELLO_USE_SRTP_EXT,
               SSL_R_BAD_SRTP_MKI_VALUE);
        *al = SSL_AD_DECODE_ERROR;
        return 1;
    }

    return 0;
}

int ssl_add_serverhello_use_srtp_ext(SSL *s, unsigned char *p, int *len,
                                     int maxlen)
{
    if (p) {
        if (maxlen < 5) {
            SSLerr(SSL_F_SSL_ADD_SERVERHELLO_USE_SRTP_EXT,
                   SSL_R_SRTP_PROTECTION_PROFILE_LIST_TOO_LONG);
            return 1;
        }

        if (s->srtp_profile == 0) {
            SSLerr(SSL_F_SSL_ADD_SERVERHELLO_USE_SRTP_EXT,
                   SSL_R_USE_SRTP_NOT_NEGOTIATED);
            return 1;
        }
        s2n(2, p);
        s2n(s->srtp_profile->id, p);
        *p++ = 0;
    }
    *len = 5;

    return 0;
}

int ssl_parse_serverhello_use_srtp_ext(SSL *s, unsigned char *d, int len,
                                       int *al)
{
    unsigned id;
    int i;
    int ct;

    STACK_OF(SRTP_PROTECTION_PROFILE) *clnt;
    SRTP_PROTECTION_PROFILE *prof;

    if (len != 5) {
        SSLerr(SSL_F_SSL_PARSE_SERVERHELLO_USE_SRTP_EXT,
               SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
        *al = SSL_AD_DECODE_ERROR;
        return 1;
    }

    n2s(d, ct);
    if (ct != 2) {
        SSLerr(SSL_F_SSL_PARSE_SERVERHELLO_USE_SRTP_EXT,
               SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
        *al = SSL_AD_DECODE_ERROR;
        return 1;
    }

    n2s(d, id);
    if (*d) {                   /* Must be no MKI, since we never offer one */
        SSLerr(SSL_F_SSL_PARSE_SERVERHELLO_USE_SRTP_EXT,
               SSL_R_BAD_SRTP_MKI_VALUE);
        *al = SSL_AD_ILLEGAL_PARAMETER;
        return 1;
    }

    clnt = SSL_get_srtp_profiles(s);

    /* Throw an error if the server gave us an unsolicited extension */
    if (clnt == NULL) {
        SSLerr(SSL_F_SSL_PARSE_SERVERHELLO_USE_SRTP_EXT,
               SSL_R_NO_SRTP_PROFILES);
        *al = SSL_AD_DECODE_ERROR;
        return 1;
    }

    /*
     * Check to see if the server gave us something we support (and
     * presumably offered)
     */
    for (i = 0; i < sk_SRTP_PROTECTION_PROFILE_num(clnt); i++) {
        prof = sk_SRTP_PROTECTION_PROFILE_value(clnt, i);

        if (prof->id == id) {
            s->srtp_profile = prof;
            *al = 0;
            return 0;
        }
    }

    SSLerr(SSL_F_SSL_PARSE_SERVERHELLO_USE_SRTP_EXT,
           SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
    *al = SSL_AD_DECODE_ERROR;
    return 1;
}

#endif