From: Andre Noll <maan@systemlinux.org>
Date: Sat, 7 Apr 2012 22:25:42 +0000 (+0200)
Subject: audiod: Check pointers passed to btr_get_node_start().
X-Git-Tag: v0.4.11~19
X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=commitdiff_plain;h=8f5de4b6e1c1299b0d8cf894474cad049f6b0958

audiod: Check pointers passed to btr_get_node_start().

If the receiver or writer buffer tree node pointer is NULL, we'll segfault due
to a a NULL pointer dereference in btr_get_node_start(). Although this might
not be triggerable, it does not hurt to be defensive here.
---

diff --git a/audiod.c b/audiod.c
index aefac612..40603c4e 100644
--- a/audiod.c
+++ b/audiod.c
@@ -250,7 +250,7 @@ char *get_time_string(int slot_num)
 	 */
 	length = stat_task->length_seconds;
 	tmp = &stat_task->server_stream_start;
-	if (s && s->wns) { /* writer active in this slot */
+	if (s && s->wns && s->wns[0].btrn) { /* writer active in this slot */
 		btr_get_node_start(s->wns[0].btrn, &wstime);
 		if (wstime.tv_sec != 0) { /* writer wrote something */
 			if (s->server_stream_start.tv_sec == 0) {
@@ -267,7 +267,7 @@ char *get_time_string(int slot_num)
 		tv_diff(tmp, &stat_task->sa_time_diff, &sss);
 	else
 		tv_add(tmp, &stat_task->sa_time_diff, &sss);
-	if (!s || !s->wns) {
+	if (!s || !s->wns || !s->wns[0].btrn) {
 		struct timeval diff;
 		tv_diff(now, &sss, &diff);
 		seconds = diff.tv_sec + stat_task->offset_seconds;
@@ -276,11 +276,14 @@ char *get_time_string(int slot_num)
 	tv_diff(now, &wstime, &wtime);
 	//PARA_CRIT_LOG("offset %d\n", s->offset_seconds);
 	seconds = s->offset_seconds;
-	btr_get_node_start(s->receiver_node->btrn, &rstime);
-	ret = tv_diff(&rstime, &sss, &rskip);
-	if (ret > 0) { /* audiod was started in the middle of the stream */
-		tv_add(&wtime, &rskip, &sum);
-		seconds += sum.tv_sec;
+	if (s->receiver_node->btrn) {
+		btr_get_node_start(s->receiver_node->btrn, &rstime);
+		ret = tv_diff(&rstime, &sss, &rskip);
+		if (ret > 0) { /* audiod was started in the middle of the stream */
+			tv_add(&wtime, &rskip, &sum);
+			seconds += sum.tv_sec;
+		} else
+			seconds += wtime.tv_sec;
 	} else
 		seconds += wtime.tv_sec;
 out: