Index: crypto/openssl/ssl/d1_both.c
===================================================================
--- crypto/openssl/ssl/d1_both.c	(revision 264059)
+++ crypto/openssl/ssl/d1_both.c	(working copy)
@@ -1458,26 +1458,36 @@ dtls1_process_heartbeat(SSL *s)
 	unsigned int payload;
 	unsigned int padding = 16; /* Use minimum padding */
 
+	if (s->msg_callback)
+		s->msg_callback(0, s->version, TLS1_RT_HEARTBEAT,
+			&s->s3->rrec.data[0], s->s3->rrec.length,
+			s, s->msg_callback_arg);
+
 	/* Read type and payload length first */
+	if (1 + 2 + 16 > s->s3->rrec.length)
+		return 0; /* silently discard */
 	hbtype = *p++;
 	n2s(p, payload);
+	if (1 + 2 + payload + 16 > s->s3->rrec.length)
+		return 0; /* silently discard per RFC 6520 sec. 4 */
 	pl = p;
 
-	if (s->msg_callback)
-		s->msg_callback(0, s->version, TLS1_RT_HEARTBEAT,
-			&s->s3->rrec.data[0], s->s3->rrec.length,
-			s, s->msg_callback_arg);
-
 	if (hbtype == TLS1_HB_REQUEST)
 		{
 		unsigned char *buffer, *bp;
+		unsigned int write_length = 1 /* heartbeat type */ +
+					    2 /* heartbeat length */ +
+					    payload + padding;
 		int r;
 
+		if (write_length > SSL3_RT_MAX_PLAIN_LENGTH)
+			return 0;
+
 		/* Allocate memory for the response, size is 1 byte
 		 * message type, plus 2 bytes payload length, plus
 		 * payload, plus padding
 		 */
-		buffer = OPENSSL_malloc(1 + 2 + payload + padding);
+		buffer = OPENSSL_malloc(write_length);
 		bp = buffer;
 
 		/* Enter response type, length and copy payload */
@@ -1488,11 +1498,11 @@ dtls1_process_heartbeat(SSL *s)
 		/* Random padding */
 		RAND_pseudo_bytes(bp, padding);
 
-		r = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buffer, 3 + payload + padding);
+		r = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buffer, write_length);
 
 		if (r >= 0 && s->msg_callback)
 			s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
-				buffer, 3 + payload + padding,
+				buffer, write_length,
 				s, s->msg_callback_arg);
 
 		OPENSSL_free(buffer);
Index: crypto/openssl/ssl/t1_lib.c
===================================================================
--- crypto/openssl/ssl/t1_lib.c	(revision 264059)
+++ crypto/openssl/ssl/t1_lib.c	(working copy)
@@ -2486,16 +2486,20 @@ tls1_process_heartbeat(SSL *s)
 	unsigned int payload;
 	unsigned int padding = 16; /* Use minimum padding */
 
+	if (s->msg_callback)
+		s->msg_callback(0, s->version, TLS1_RT_HEARTBEAT,
+			&s->s3->rrec.data[0], s->s3->rrec.length,
+			s, s->msg_callback_arg);
+
 	/* Read type and payload length first */
+	if (1 + 2 + 16 > s->s3->rrec.length)
+		return 0; /* silently discard */
 	hbtype = *p++;
 	n2s(p, payload);
+	if (1 + 2 + payload + 16 > s->s3->rrec.length)
+		return 0; /* silently discard per RFC 6520 sec. 4 */
 	pl = p;
 
-	if (s->msg_callback)
-		s->msg_callback(0, s->version, TLS1_RT_HEARTBEAT,
-			&s->s3->rrec.data[0], s->s3->rrec.length,
-			s, s->msg_callback_arg);
-
 	if (hbtype == TLS1_HB_REQUEST)
 		{
 		unsigned char *buffer, *bp;