Fix for SRTP Memory Leak

CVE-2014-3513

This issue was reported to OpenSSL on 26th September 2014, based on an original
issue and patch developed by the LibreSSL project. Further analysis of the issue
was performed by the OpenSSL team.

The fix was developed by the OpenSSL team.
Reviewed-by: NTim Hudson <tjh@openssl.org>

ssl/d1_srtp.c

@@ -167,25 +167,6 @@ static int find_profile_by_name(char *profile_name,
 	return 1;
 	}
 
-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 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;
@@ -208,11 +189,19 @@ static int ssl_ctx_make_profiles(const char *profiles_string,STACK_OF(SRTP_PROTE
 		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;
 			}
 
@@ -304,13 +293,12 @@ int ssl_add_clienthello_use_srtp_ext(SSL *s, unsigned char *p, int *len, int max
 
 int ssl_parse_clienthello_use_srtp_ext(SSL *s, unsigned char *d, int len,int *al)
 	{
-	SRTP_PROTECTION_PROFILE *cprof,*sprof;
-	STACK_OF(SRTP_PROTECTION_PROFILE) *clnt=0,*srvr;
+	SRTP_PROTECTION_PROFILE *sprof;
+	STACK_OF(SRTP_PROTECTION_PROFILE) *srvr;
         int ct;
         int mki_len;
-	int i,j;
-	int id;
-	int ret;
+	int i, srtp_pref;
+	unsigned int id;
 
          /* Length value + the MKI length */
         if(len < 3)
@@ -340,8 +328,10 @@ int ssl_parse_clienthello_use_srtp_ext(SSL *s, unsigned char *d, int len,int *al
 		return 1;
 		}
 
-        
-	clnt=sk_SRTP_PROTECTION_PROFILE_new_null();
+	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)
 		{
@@ -349,13 +339,21 @@ int ssl_parse_clienthello_use_srtp_ext(SSL *s, unsigned char *d, int len,int *al
 		ct-=2;
                 len-=2;
 
-		if(!find_profile_by_num(id,&cprof))
+		/*
+		 * 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++)
 			{
-			sk_SRTP_PROTECTION_PROFILE_push(clnt,cprof);
-			}
-		else
+			sprof = sk_SRTP_PROTECTION_PROFILE_value(srvr, i);
+			if (sprof->id == id)
 				{
-			; /* Ignore */
+				s->srtp_profile = sprof;
+				srtp_pref = i;
+				break;
+				}
 			}
 		}
 
@@ -370,36 +368,7 @@ int ssl_parse_clienthello_use_srtp_ext(SSL *s, unsigned char *d, int len,int *al
 		return 1;
 		}
 
-	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;
-				*al=0;
-				ret=0;
-				goto done;
-				}
-			}
-		}
-
-	ret=0;
-    
-done:
-	if(clnt) sk_SRTP_PROTECTION_PROFILE_free(clnt);
-
-	return ret;
+	return 0;
 	}
 
 int ssl_add_serverhello_use_srtp_ext(SSL *s, unsigned char *p, int *len, int maxlen)

ssl/t1_lib.c

@@ -1462,7 +1462,7 @@ unsigned char *ssl_add_clienthello_tlsext(SSL *s, unsigned char *buf, unsigned c
 		ret += s->alpn_client_proto_list_len;
 		}
 
-        if(SSL_get_srtp_profiles(s))
+        if(SSL_IS_DTLS(s) && SSL_get_srtp_profiles(s))
                 {
                 int el;
 
@@ -1642,7 +1642,7 @@ unsigned char *ssl_add_serverhello_tlsext(SSL *s, unsigned char *buf, unsigned c
 		}
 #endif
 
-        if(s->srtp_profile)
+        if(SSL_IS_DTLS(s) && s->srtp_profile)
                 {
                 int el;
 
@@ -2433,7 +2433,8 @@ static int ssl_scan_clienthello_tlsext(SSL *s, unsigned char **p, unsigned char
 			}
 
 		/* session ticket processed earlier */
-		else if (type == TLSEXT_TYPE_use_srtp)
+		else if (SSL_IS_DTLS(s) && SSL_get_srtp_profiles(s)
+				&& type == TLSEXT_TYPE_use_srtp)
                         {
 			if(ssl_parse_clienthello_use_srtp_ext(s, data, size,
 							      al))
@@ -2776,7 +2777,7 @@ static int ssl_scan_serverhello_tlsext(SSL *s, unsigned char **p, unsigned char
 				}
 			}
 #endif
-		else if (type == TLSEXT_TYPE_use_srtp)
+		else if (SSL_IS_DTLS(s) && type == TLSEXT_TYPE_use_srtp)
                         {
                         if(ssl_parse_serverhello_use_srtp_ext(s, data, size,
 							      al))