[alsa-devel] [PATCH] ALSA: oxfw: fix NULL pointer dereference to unused stream structure

[Takashi Sakamoto]

ALSA oxfw driver supports Griffin FireWave. This device supports one
isochronous stream for PCM playback. Current driver executes code to
wait event for stream structure of opposite direction. This causes
NULL pointer dereference.

This commit fixes the bug.

Fixes: ac5d77864cfc ("ALSA: oxfw: support AMDTP domain")
Signed-off-by: Takashi Sakamoto <o-takashi at sakamocchi.jp>
---
 sound/firewire/oxfw/oxfw-stream.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/sound/firewire/oxfw/oxfw-stream.c b/sound/firewire/oxfw/oxfw-stream.c
index 0318dc4dcc55..3c9a796b6526 100644
--- a/sound/firewire/oxfw/oxfw-stream.c
+++ b/sound/firewire/oxfw/oxfw-stream.c
@@ -350,13 +350,18 @@ int snd_oxfw_stream_start_duplex(struct snd_oxfw *oxfw)
 
 		// Wait first packet.
 		if (!amdtp_stream_wait_callback(&oxfw->rx_stream,
-						CALLBACK_TIMEOUT) ||
-		    !amdtp_stream_wait_callback(&oxfw->tx_stream,
 						CALLBACK_TIMEOUT)) {
 			err = -ETIMEDOUT;
 			goto error;
 		}
 
+		if (oxfw->has_output) {
+			if (!amdtp_stream_wait_callback(&oxfw->tx_stream,
+							CALLBACK_TIMEOUT)) {
+				err = -ETIMEDOUT;
+				goto error;
+			}
+		}
 	}
 
 	return 0;
-- 
2.20.1