ssl/d1_srtp.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/bytestring.h>
#include <openssl/obj.h>
#include <openssl/err.h>

#include "ssl_locl.h"
#include <openssl/srtp.h>


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,
    },
#if 0
    {
    "SRTP_NULL_SHA1_80",
    SRTP_NULL_SHA1_80,
    },
    {
    "SRTP_NULL_SHA1_32",
    SRTP_NULL_SHA1_32,
    },
#endif
    {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 1;
			}

		p++;
		}

	return 0;
	}

static int find_profile_by_num(unsigned profile_num,
			       SRTP_PROTECTION_PROFILE **pptr)
	{
	SRTP_PROTECTION_PROFILE *p;

	p=srtp_known_profiles;
	while(p->name)
		{
		if(p->id == profile_num)
			{
			*pptr=p;
			return 1;
			}
		p++;
		}

	return 0;
	}

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()))
		{
		OPENSSL_PUT_ERROR(SSL, ssl_ctx_make_profiles, SSL_R_SRTP_COULD_NOT_ALLOCATE_PROFILES);
		return 0;
		}
    
	do
		{
		col=strchr(ptr,':');

		if(find_profile_by_name(ptr,&p,
					 col ? col-ptr : (int)strlen(ptr)))
			{
			sk_SRTP_PROTECTION_PROFILE_push(profiles,p);
			}
		else
			{
			OPENSSL_PUT_ERROR(SSL, ssl_ctx_make_profiles, SSL_R_SRTP_UNKNOWN_PROTECTION_PROFILE);
			return 0;
			}

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

	*out=profiles;
    
	return 1;
	}

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

int SSL_set_srtp_profiles(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;
	}

int SSL_CTX_set_tlsext_use_srtp(SSL_CTX *ctx, const char *profiles)
	{
	/* This API inverts its return value. */
	return !SSL_CTX_set_srtp_profiles(ctx, profiles);
	}

int SSL_set_tlsext_use_srtp(SSL *s, const char *profiles)
	{
	/* This API inverts its return value. */
	return !SSL_set_srtp_profiles(s, profiles);
	}

/* 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)
			{
			OPENSSL_PUT_ERROR(SSL, ssl_add_clienthello_use_srtp_ext, SSL_R_EMPTY_SRTP_PROTECTION_PROFILE_LIST);
			return 0;
			}

		if((2 + ct*2 + 1) > maxlen)
			{
			OPENSSL_PUT_ERROR(SSL, ssl_add_clienthello_use_srtp_ext, SSL_R_SRTP_PROTECTION_PROFILE_LIST_TOO_LONG);
			return 0;
			}

                /* 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 1;
	}


int ssl_parse_clienthello_use_srtp_ext(SSL *s, CBS *cbs, int *out_alert)
	{
	CBS profile_ids, srtp_mki;
	SRTP_PROTECTION_PROFILE *cprof, *sprof;
	STACK_OF(SRTP_PROTECTION_PROFILE) *clnt = 0,*srvr;
	size_t i,j;
	int ret = 0;

	if (!CBS_get_u16_length_prefixed(cbs, &profile_ids) ||
		CBS_len(&profile_ids) < 2 ||
		!CBS_get_u8_length_prefixed(cbs, &srtp_mki) ||
		CBS_len(cbs) != 0)
		{
		OPENSSL_PUT_ERROR(SSL, ssl_parse_clienthello_use_srtp_ext, SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
		*out_alert = SSL_AD_DECODE_ERROR;
		goto done;
		}

	clnt = sk_SRTP_PROTECTION_PROFILE_new_null();

	while (CBS_len(&profile_ids) > 0)
		{
		uint16_t profile_id;

		if (!CBS_get_u16(&profile_ids, &profile_id))
			{
			*out_alert = SSL_AD_DECODE_ERROR;
			goto done;
			}

		if (find_profile_by_num(profile_id, &cprof))
			{
			sk_SRTP_PROTECTION_PROFILE_push(clnt, cprof);
			}
		}

	/* Discard the MKI value for now. */

	srvr = SSL_get_srtp_profiles(s);

	/* Pick our most preferred profile. If no profiles have been
	 configured then the outer loop doesn't run 
	 (sk_SRTP_PROTECTION_PROFILE_num() = -1)
	 and so we just return without doing anything */
	for(i=0;i<sk_SRTP_PROTECTION_PROFILE_num(srvr);i++)
		{
		sprof=sk_SRTP_PROTECTION_PROFILE_value(srvr,i);

		for(j=0;j<sk_SRTP_PROTECTION_PROFILE_num(clnt);j++)
			{
			cprof=sk_SRTP_PROTECTION_PROFILE_value(clnt,j);
            
			if(cprof->id==sprof->id)
				{
				s->srtp_profile = sprof;
				ret = 1;
				goto done;
				}
			}
		}

	ret = 1;
    
done:
	if(clnt) sk_SRTP_PROTECTION_PROFILE_free(clnt);

	return ret;
	}

int ssl_add_serverhello_use_srtp_ext(SSL *s, unsigned char *p, int *len, int maxlen)
	{
	if(p)
		{
		if(maxlen < 5)
			{
			OPENSSL_PUT_ERROR(SSL, ssl_add_serverhello_use_srtp_ext, SSL_R_SRTP_PROTECTION_PROFILE_LIST_TOO_LONG);
			return 0;
			}

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

int ssl_parse_serverhello_use_srtp_ext(SSL *s, CBS *cbs, int *out_alert)
	{
	CBS profile_ids, srtp_mki;
	uint16_t profile_id;
	size_t i;

	STACK_OF(SRTP_PROTECTION_PROFILE) *clnt;
	SRTP_PROTECTION_PROFILE *prof;

	/* The extension consists of a u16-prefixed profile ID list containing a
	 * single uint16_t profile ID, then followed by a u8-prefixed srtp_mki
	 * field.
	 *
	 * See https://tools.ietf.org/html/rfc5764#section-4.1.1
	 */
	if (!CBS_get_u16_length_prefixed(cbs, &profile_ids) ||
		!CBS_get_u16(&profile_ids, &profile_id) ||
		CBS_len(&profile_ids) != 0 ||
		!CBS_get_u8_length_prefixed(cbs, &srtp_mki) ||
		CBS_len(cbs) != 0)
		{
		OPENSSL_PUT_ERROR(SSL, ssl_parse_serverhello_use_srtp_ext, SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
		*out_alert = SSL_AD_DECODE_ERROR;
		return 0;
		}

	if (CBS_len(&srtp_mki) != 0)
		{
		/* Must be no MKI, since we never offer one. */
		OPENSSL_PUT_ERROR(SSL, ssl_parse_serverhello_use_srtp_ext, SSL_R_BAD_SRTP_MKI_VALUE);
		*out_alert = SSL_AD_ILLEGAL_PARAMETER;
		return 0;
		}

	clnt=SSL_get_srtp_profiles(s);

	/* Throw an error if the server gave us an unsolicited extension */
	if (clnt == NULL)
		{
		OPENSSL_PUT_ERROR(SSL, ssl_parse_serverhello_use_srtp_ext, SSL_R_NO_SRTP_PROFILES);
		*out_alert = SSL_AD_DECODE_ERROR;
		return 0;
		}
    
	/* 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 == profile_id)
			{
			s->srtp_profile=prof;
			*out_alert = 0;
			return 1;
			}
		}

	OPENSSL_PUT_ERROR(SSL, ssl_parse_serverhello_use_srtp_ext, SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
	*out_alert = SSL_AD_ILLEGAL_PARAMETER;
	return 0;
	}