From bd6941cfaa31ee8a3f8661cb98227a5cbcc0f9f3 Mon Sep 17 00:00:00 2001
From: "Dr. Stephen Henson" <steve@openssl.org>
Date: Sat, 31 Dec 2011 23:00:36 +0000
Subject: PR: 2658 Submitted by: Robin Seggelmann <seggelmann@fh-muenster.de>
 Reviewed by: steve

Support for TLS/DTLS heartbeats.
---
 ssl/d1_both.c | 152 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 151 insertions(+), 1 deletion(-)

(limited to 'ssl/d1_both.c')

diff --git a/ssl/d1_both.c b/ssl/d1_both.c
index 89338e9430..0a84f95711 100644
--- a/ssl/d1_both.c
+++ b/ssl/d1_both.c
@@ -1084,7 +1084,11 @@ int dtls1_read_failed(SSL *s, int code)
 		return code;
 		}
 
-	if ( ! SSL_in_init(s))  /* done, no need to send a retransmit */
+#ifndef OPENSSL_NO_HEARTBEATS
+	if (!SSL_in_init(s) && !s->tlsext_hb_pending)  /* done, no need to send a retransmit */
+#else
+	if (!SSL_in_init(s))  /* done, no need to send a retransmit */
+#endif
 		{
 		BIO_set_flags(SSL_get_rbio(s), BIO_FLAGS_READ);
 		return code;
@@ -1438,3 +1442,149 @@ int dtls1_shutdown(SSL *s)
 #endif
 	return ret;
 	}
+
+#ifndef OPENSSL_NO_HEARTBEATS
+int
+dtls1_process_heartbeat(SSL *s)
+	{
+	unsigned char *p = &s->s3->rrec.data[0], *pl;
+	unsigned short hbtype;
+	unsigned int payload;
+	unsigned int padding = 16; /* Use minimum padding */
+
+	/* Read type and payload length first */
+	hbtype = *p++;
+	n2s(p, payload);
+	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;
+		int r;
+
+		/* 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);
+		bp = buffer;
+
+		/* Enter response type, length and copy payload */
+		*bp++ = TLS1_HB_RESPONSE;
+		s2n(payload, bp);
+		memcpy(bp, pl, payload);
+		/* Random padding */
+		RAND_pseudo_bytes(p, padding);
+
+		r = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buffer, 3 + payload + padding);
+
+		if (r >= 0 && s->msg_callback)
+			s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
+				buffer, 3 + payload + padding,
+				s, s->msg_callback_arg);
+
+		OPENSSL_free(buffer);
+
+		if (r < 0)
+			return r;
+		}
+	else if (hbtype == TLS1_HB_RESPONSE)
+		{
+		unsigned int seq;
+
+		/* We only send sequence numbers (2 bytes unsigned int),
+		 * and 16 random bytes, so we just try to read the
+		 * sequence number */
+		n2s(pl, seq);
+
+		if (payload == 18 && seq == s->tlsext_hb_seq)
+			{
+			dtls1_stop_timer(s);
+			s->tlsext_hb_seq++;
+			s->tlsext_hb_pending = 0;
+			}
+		}
+
+	return 0;
+	}
+
+int
+dtls1_heartbeat(SSL *s)
+	{
+	unsigned char *buf, *p;
+	int ret;
+	unsigned int payload = 18; /* Sequence number + random bytes */
+	unsigned int padding = 16; /* Use minimum padding */
+
+	/* Only send if peer supports and accepts HB requests... */
+	if (!(s->tlsext_heartbeat & SSL_TLSEXT_HB_ENABLED) ||
+	    s->tlsext_heartbeat & SSL_TLSEXT_HB_DONT_SEND_REQUESTS)
+		{
+		SSLerr(SSL_F_DTLS1_HEARTBEAT,SSL_R_TLS_HEARTBEAT_PEER_DOESNT_ACCEPT);
+		return -1;
+		}
+
+	/* ...and there is none in flight yet... */
+	if (s->tlsext_hb_pending)
+		{
+		SSLerr(SSL_F_DTLS1_HEARTBEAT,SSL_R_TLS_HEARTBEAT_PENDING);
+		return -1;
+		}
+
+	/* ...and no handshake in progress. */
+	if (SSL_in_init(s) || s->in_handshake)
+		{
+		SSLerr(SSL_F_DTLS1_HEARTBEAT,SSL_R_UNEXPECTED_MESSAGE);
+		return -1;
+		}
+
+	/* Check if padding is too long, payload and padding
+	 * must not exceed 2^14 - 3 = 16381 bytes in total.
+	 */
+	OPENSSL_assert(payload + padding <= 16381);
+
+	/* Create HeartBeat message, we just use a sequence number
+	 * as payload to distuingish different messages and add
+	 * some random stuff.
+	 *  - Message Type, 1 byte
+	 *  - Payload Length, 2 bytes (unsigned int)
+	 *  - Payload, the sequence number (2 bytes uint)
+	 *  - Payload, random bytes (16 bytes uint)
+	 *  - Padding
+	 */
+	buf = OPENSSL_malloc(1 + 2 + payload + padding);
+	p = buf;
+	/* Message Type */
+	*p++ = TLS1_HB_REQUEST;
+	/* Payload length (18 bytes here) */
+	s2n(payload, p);
+	/* Sequence number */
+	s2n(s->tlsext_hb_seq, p);
+	/* 16 random bytes */
+	RAND_pseudo_bytes(p, 16);
+	p += 16;
+	/* Random padding */
+	RAND_pseudo_bytes(p, padding);
+
+	ret = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buf, 3 + payload + padding);
+	if (ret >= 0)
+		{
+		if (s->msg_callback)
+			s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
+				buf, 3 + payload + padding,
+				s, s->msg_callback_arg);
+
+		dtls1_start_timer(s);
+		s->tlsext_hb_pending = 1;
+		}
+
+	OPENSSL_free(buf);
+
+	return ret;
+	}
+#endif
-- 
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