From ad3d95222d94918cfe7e7f27b40a07b18af871a5 Mon Sep 17 00:00:00 2001
From: "Dr. Stephen Henson" <steve@openssl.org>
Date: Fri, 9 Mar 2012 15:52:09 +0000
Subject: [PATCH] PR: 2756 Submitted by: Robin Seggelmann
 <seggelmann@fh-muenster.de>

Fix DTLS timeout handling.
---
 ssl/d1_lib.c   | 43 ++++++++++++++++++++++++++-----------------
 ssl/d1_pkt.c   | 12 +++---------
 ssl/ssl_locl.h |  1 +
 3 files changed, 30 insertions(+), 26 deletions(-)

diff --git a/ssl/d1_lib.c b/ssl/d1_lib.c
index 7603715159..c6ca85f1bb 100644
--- a/ssl/d1_lib.c
+++ b/ssl/d1_lib.c
@@ -381,6 +381,7 @@ void dtls1_double_timeout(SSL *s)
 void dtls1_stop_timer(SSL *s)
 	{
 	/* Reset everything */
+	memset(&(s->d1->timeout), 0, sizeof(struct dtls1_timeout_st));
 	memset(&(s->d1->next_timeout), 0, sizeof(struct timeval));
 	s->d1->timeout_duration = 1;
 	BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0, &(s->d1->next_timeout));
@@ -388,10 +389,28 @@ void dtls1_stop_timer(SSL *s)
 	dtls1_clear_record_buffer(s);
 	}
 
+int dtls1_check_timeout_num(SSL *s)
+	{
+	s->d1->timeout.num_alerts++;
+
+	/* Reduce MTU after 2 unsuccessful retransmissions */
+	if (s->d1->timeout.num_alerts > 2)
+		{
+		s->d1->mtu = BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0, NULL);		
+		}
+
+	if (s->d1->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT)
+		{
+		/* fail the connection, enough alerts have been sent */
+		SSLerr(SSL_F_DTLS1_HANDLE_TIMEOUT,SSL_R_READ_TIMEOUT_EXPIRED);
+		return -1;
+		}
+
+	return 0;
+	}
+
 int dtls1_handle_timeout(SSL *s)
 	{
-	DTLS1_STATE *state;
-
 	/* if no timer is expired, don't do anything */
 	if (!dtls1_is_timer_expired(s))
 		{
@@ -399,24 +418,14 @@ int dtls1_handle_timeout(SSL *s)
 		}
 
 	dtls1_double_timeout(s);
-	state = s->d1;
-	state->timeout.num_alerts++;
-	if ( state->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT)
-		{
-		/* fail the connection, enough alerts have been sent */
-		SSLerr(SSL_F_DTLS1_HANDLE_TIMEOUT,SSL_R_READ_TIMEOUT_EXPIRED);
+
+	if (dtls1_check_timeout_num(s) < 0)
 		return -1;
-		}
 
-	state->timeout.read_timeouts++;
-	if ( state->timeout.read_timeouts > DTLS1_TMO_READ_COUNT)
+	s->d1->timeout.read_timeouts++;
+	if (s->d1->timeout.read_timeouts > DTLS1_TMO_READ_COUNT)
 		{
-		state->timeout.read_timeouts = 1;
-		}
-
-	if (state->timeout_duration > 2)
-		{
-		s->d1->mtu = BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0, NULL);		
+		s->d1->timeout.read_timeouts = 1;
 		}
 
 	dtls1_start_timer(s);
diff --git a/ssl/d1_pkt.c b/ssl/d1_pkt.c
index de30a505a6..6d245736f6 100644
--- a/ssl/d1_pkt.c
+++ b/ssl/d1_pkt.c
@@ -179,7 +179,6 @@ static int dtls1_record_needs_buffering(SSL *s, SSL3_RECORD *rr,
 static int dtls1_buffer_record(SSL *s, record_pqueue *q,
 	unsigned char *priority);
 static int dtls1_process_record(SSL *s);
-static void dtls1_clear_timeouts(SSL *s);
 
 /* copy buffered record into SSL structure */
 static int
@@ -682,7 +681,6 @@ again:
 		goto again;   /* get another record */
 		}
 
-	dtls1_clear_timeouts(s);  /* done waiting */
 	return(1);
 
 	}
@@ -1152,6 +1150,9 @@ start:
 		 */
 		if (msg_hdr.type == SSL3_MT_FINISHED)
 			{
+			if (dtls1_check_timeout_num(s) < 0)
+				return -1;
+
 			dtls1_retransmit_buffered_messages(s);
 			rr->length = 0;
 			goto start;
@@ -1765,10 +1766,3 @@ dtls1_reset_seq_numbers(SSL *s, int rw)
 
 	memset(seq, 0x00, seq_bytes);
 	}
-
-
-static void
-dtls1_clear_timeouts(SSL *s)
-	{
-	memset(&(s->d1->timeout), 0x00, sizeof(struct dtls1_timeout_st));
-	}
diff --git a/ssl/ssl_locl.h b/ssl/ssl_locl.h
index cea622a2a6..4e4e79b99d 100644
--- a/ssl/ssl_locl.h
+++ b/ssl/ssl_locl.h
@@ -943,6 +943,7 @@ void dtls1_get_ccs_header(unsigned char *data, struct ccs_header_st *ccs_hdr);
 void dtls1_reset_seq_numbers(SSL *s, int rw);
 long dtls1_default_timeout(void);
 struct timeval* dtls1_get_timeout(SSL *s, struct timeval* timeleft);
+int dtls1_check_timeout_num(SSL *s);
 int dtls1_handle_timeout(SSL *s);
 const SSL_CIPHER *dtls1_get_cipher(unsigned int u);
 void dtls1_start_timer(SSL *s);