PR: 2115

Submitted by: Robin Seggelmann <seggelmann@fh-muenster.de>
Approved by: steve@openssl.org

Add Renegotiation extension to DTLS, fix DTLS ClientHello processing bug.

1 files changed, 191 insertions, 0 deletions

diff --git a/ssl/d1_lib.c b/ssl/d1_lib.c
index 2786b61c29..99935563d1 100644
--- a/ssl/d1_lib.c
+++ b/ssl/d1_lib.c
@@ -382,3 +382,194 @@ int dtls1_listen(SSL *s, struct sockaddr *client)
 	(void) BIO_dgram_get_peer(SSL_get_rbio(s), client);
 	return 1;
 	}
+
+#ifndef OPENSSL_NO_TLSEXT
+unsigned char *ssl_add_clienthello_dtlsext(SSL *s, unsigned char *p, unsigned char *limit)
+	{
+	int extdatalen = 0;
+	unsigned char *ret = p;
+	int el;
+
+	ret+=2;
+	
+	if (ret>=limit) return NULL; /* this really never occurs, but ... */
+
+	/* Renegotiate extension */
+	if(!ssl_add_clienthello_renegotiate_ext(s, 0, &el, 0))
+		{
+		SSLerr(SSL_F_SSL_ADD_CLIENTHELLO_TLSEXT, ERR_R_INTERNAL_ERROR);
+		return NULL;
+		}
+
+	if((limit - p - 4 - el) < 0) return NULL;
+	  
+	s2n(TLSEXT_TYPE_renegotiate,ret);
+	s2n(el,ret);
+
+	if(!ssl_add_clienthello_renegotiate_ext(s, ret, &el, el))
+		{
+		SSLerr(SSL_F_SSL_ADD_CLIENTHELLO_TLSEXT, ERR_R_INTERNAL_ERROR);
+		return NULL;
+		}
+
+	ret += el;
+
+	if ((extdatalen = ret-p-2)== 0) 
+		return p;
+
+	s2n(extdatalen,p);
+
+	return ret;
+	}
+
+int ssl_parse_clienthello_dtlsext(SSL *s, unsigned char **p, unsigned char *d, int n, int *al)
+	{
+	unsigned short type;
+	unsigned short size;
+	unsigned short len;
+	unsigned char *data = *p;
+	int renegotiate_seen = 0;
+
+	if (data >= (d+n-2))
+		{
+		if (s->new_session
+			&& !(s->ctx->options & SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION))
+			{
+			/* We should always see one extension: the renegotiate extension */
+	 		SSLerr(SSL_F_SSL_PARSE_CLIENTHELLO_TLSEXT, SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED);
+			*al = SSL_AD_ILLEGAL_PARAMETER; /* is this the right alert? */
+			return 0;
+			}
+		return 1;
+		}
+	n2s(data,len);
+
+	if (data > (d+n-len)) 
+		return 1;
+
+	while (data <= (d+n-4))
+		{
+		n2s(data,type);
+		n2s(data,size);
+		
+		if (data+size > (d+n))
+	   		return 1;
+		
+		if (type == TLSEXT_TYPE_renegotiate)
+			{
+			if(!ssl_parse_clienthello_renegotiate_ext(s, data, size, al))
+				return 0;
+			renegotiate_seen = 1;
+			}
+		
+		data+=size;
+		}
+
+	if (s->new_session && !renegotiate_seen
+		&& !(s->ctx->options & SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION))
+		{
+		*al = SSL_AD_ILLEGAL_PARAMETER; /* is this the right alert? */
+	 	SSLerr(SSL_F_SSL_PARSE_CLIENTHELLO_TLSEXT, SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED);
+		return 0;
+		}
+
+	*p = data;
+	return 1;
+	}
+
+unsigned char *ssl_add_serverhello_dtlsext(SSL *s, unsigned char *p, unsigned char *limit)
+	{
+	int extdatalen = 0;
+	unsigned char *ret = p;
+	
+	ret+=2;
+	
+	if (ret>=limit) return NULL; /* this really never occurs, but ... */
+	
+	if(s->s3->send_connection_binding)
+		{
+		int el;
+
+		if(!ssl_add_serverhello_renegotiate_ext(s, 0, &el, 0))
+			{
+			SSLerr(SSL_F_SSL_ADD_SERVERHELLO_TLSEXT, ERR_R_INTERNAL_ERROR);
+			return NULL;
+			}
+
+		if((limit - p - 4 - el) < 0) return NULL;
+          
+		s2n(TLSEXT_TYPE_renegotiate,ret);
+		s2n(el,ret);
+
+		if(!ssl_add_serverhello_renegotiate_ext(s, ret, &el, el))
+			{
+			SSLerr(SSL_F_SSL_ADD_SERVERHELLO_TLSEXT, ERR_R_INTERNAL_ERROR);
+			return NULL;
+			}
+
+		ret += el;
+		}
+
+	if ((extdatalen = ret-p-2)== 0) 
+		return p;
+
+	s2n(extdatalen,p);
+
+	return ret;
+	}
+
+int ssl_parse_serverhello_dtlsext(SSL *s, unsigned char **p, unsigned char *d, int n, int *al)
+	{
+	unsigned short type;
+	unsigned short size;
+	unsigned short len;
+	unsigned char *data = *p;
+	int renegotiate_seen = 0;
+	
+	if (data >= (d+n-2))
+		{
+		if (s->new_session
+			&& !(s->ctx->options & SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION))
+			{
+			/* We should always see one extension: the renegotiate extension */
+	 		SSLerr(SSL_F_SSL_PARSE_SERVERHELLO_TLSEXT, SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED);
+			*al = SSL_AD_ILLEGAL_PARAMETER; /* is this the right alert? */
+			return 0;
+			}
+		return 1;
+		}
+	n2s(data,len);
+	
+	if (data > (d+n-len)) 
+		return 1;
+	
+	while (data <= (d+n-4))
+		{
+		n2s(data,type);
+		n2s(data,size);
+		
+		if (data+size > (d+n))
+	   		return 1;
+		
+		if (type == TLSEXT_TYPE_renegotiate)
+			{
+			if(!ssl_parse_serverhello_renegotiate_ext(s, data, size, al))
+				return 0;
+			renegotiate_seen = 1;
+			}
+		
+		data+=size;
+		}
+
+	if (s->new_session && !renegotiate_seen
+		&& !(s->ctx->options & SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION))
+		{
+		*al = SSL_AD_ILLEGAL_PARAMETER; /* is this the right alert? */
+	 	SSLerr(SSL_F_SSL_PARSE_SERVERHELLO_TLSEXT, SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED);
+		return 0;
+		}
+
+	*p = data;
+	return 1;
+	}
+#endif