[PATCH 5.15 075/279] ALSA: usb-audio: fix null pointer dereference on pointer cs_desc

Greg Kroah-Hartman
2021-11-24T13:49:45Z

From: Chengfeng Ye <cyeaa@connect.ust.hk>

[ Upstream commit b97053df0f04747c3c1e021ecbe99db675342954 ]

The pointer cs_desc return from snd_usb_find_clock_source could
be null, so there is a potential null pointer dereference issue.
Fix this by adding a null check before dereference.

Signed-off-by: Chengfeng Ye <cyeaa@connect.ust.hk>
Link: https://lore.kernel.org/r/20211024111736.11342-1-cyeaa@connect.ust.hk
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
sound/usb/clock.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/sound/usb/clock.c b/sound/usb/clock.c
index 81d5ce07d548b..98345a695dccb 100644
--- a/sound/usb/clock.c
+++ b/sound/usb/clock.c
@@ -496,6 +496,10 @@ int snd_usb_set_sample_rate_v2v3(struct snd_usb_audio *chip,
union uac23_clock_source_desc *cs_desc;

cs_desc = snd_usb_find_clock_source(chip, clock, fmt->protocol);
+
+ if (!cs_desc)
+ return 0;
+
if (fmt->protocol == UAC_VERSION_3)
bmControls = le32_to_cpu(cs_desc->v3.bmControls);
else
--
2.33.0