From: Joshua Colp <jcolp@digium.com>
Date: Thu, 2 Nov 2017 10:34:46 +0000 (-0300)
Subject: core: Don't attempt to write to a stream that does not exist.
X-Git-Tag: 15.2.0-rc1~193^2
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=e9b53dcd9b6e63ae15edf175c6109f1f40ea8709;p=thirdparty%2Fasterisk.git

core: Don't attempt to write to a stream that does not exist.

When a frame is provided to ast_write ensure that a multistream
capable channel has a stream for it before attempting to give it
to the channel driver. In some cases (such as a deferred SDP
negotiation) the stream may not yet exist.

ASTERISK-27364

Change-Id: Icf84ca982a67cdd6e9a71851eb7eb1bd0e865276
---

diff --git a/main/channel.c b/main/channel.c
index 7d6e5db07a..7eb40d1955 100644
--- a/main/channel.c
+++ b/main/channel.c
@@ -5054,7 +5054,11 @@ int ast_write_stream(struct ast_channel *chan, int stream_num, struct ast_frame
 	case AST_FRAME_VIDEO:
 		/* XXX Handle translation of video codecs one day XXX */
 		if (ast_channel_tech(chan)->write_stream) {
-			res = ast_channel_tech(chan)->write_stream(chan, ast_stream_get_position(stream), fr);
+			if (stream) {
+				res = ast_channel_tech(chan)->write_stream(chan, ast_stream_get_position(stream), fr);
+			} else {
+				res = 0;
+			}
 		} else if ((stream == default_stream) && ast_channel_tech(chan)->write_video) {
 			res = ast_channel_tech(chan)->write_video(chan, fr);
 		} else {
@@ -5063,7 +5067,11 @@ int ast_write_stream(struct ast_channel *chan, int stream_num, struct ast_frame
 		break;
 	case AST_FRAME_MODEM:
 		if (ast_channel_tech(chan)->write_stream) {
-			res = ast_channel_tech(chan)->write_stream(chan, ast_stream_get_position(stream), fr);
+			if (stream) {
+				res = ast_channel_tech(chan)->write_stream(chan, ast_stream_get_position(stream), fr);
+			} else {
+				res = 0;
+			}
 		} else if ((stream == default_stream) && ast_channel_tech(chan)->write) {
 			res = ast_channel_tech(chan)->write(chan, fr);
 		} else {
@@ -5251,7 +5259,11 @@ int ast_write_stream(struct ast_channel *chan, int stream_num, struct ast_frame
 			f = NULL;
 		} else {
 			if (ast_channel_tech(chan)->write_stream) {
-				res = ast_channel_tech(chan)->write_stream(chan, ast_stream_get_position(stream), f);
+				if (stream) {
+					res = ast_channel_tech(chan)->write_stream(chan, ast_stream_get_position(stream), f);
+				} else {
+					res = 0;
+				}
 			} else if ((stream == default_stream) && ast_channel_tech(chan)->write) {
 				res = ast_channel_tech(chan)->write(chan, f);
 			} else {