[alsa-devel] [PATCH v2 9/9] ALSA: usb-audio: WARN_ON when alts is passed as NULL

Eldad Zack eldad at fogrefinery.com
Sat Aug 3 10:51:15 CEST 2013

Prevent NULL dereference in snd_usb_add_endpoints(), when
alts is passed as NULL. In this case, WARN (since this is
a non-fatal bug) and return NULL ep. Call sites treat a NULL
return value as an error.

Signed-off-by: Eldad Zack <eldad at fogrefinery.com>
 sound/usb/endpoint.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c
index 7a444b5..92ea945 100644
--- a/sound/usb/endpoint.c
+++ b/sound/usb/endpoint.c
@@ -418,6 +418,9 @@ struct snd_usb_endpoint *snd_usb_add_endpoint(struct snd_usb_audio *chip,
 	struct snd_usb_endpoint *ep;
 	int is_playback = direction == SNDRV_PCM_STREAM_PLAYBACK;
+	if (WARN_ON(!alts))
+		return NULL;
 	list_for_each_entry(ep, &chip->ep_list, list) {

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