[PATCH] [RFC PATCH] ALSA: usb-audio: endpoint: Prevent NULL pointer deference in snd_usb_endpoint_close

From: Rajashekar kuruva
Date: Fri Apr 26 2024 - 08:26:17 EST


When multiple plug-in and plug-out events occur,
there is a risk of encountering a NULL pointer dereference
leading to a kernel panic during a headset use-case.
this issue arises in the snd_usb_endpoint_close function

To avoid check if ep->iface_ref is not null before decrementing
its opened count. If ep->iface_ref is null, we skip the decrement
and the subsequent logic.

Signed-off-by: Rajashekar kuruva <quic_kuruva@xxxxxxxxxxx>
---
sound/usb/endpoint.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c
index 8f65349a06d3..0e3101b7e392 100644
--- a/sound/usb/endpoint.c
+++ b/sound/usb/endpoint.c
@@ -950,7 +950,7 @@ void snd_usb_endpoint_close(struct snd_usb_audio *chip,
usb_audio_dbg(chip, "Closing EP 0x%x (count %d)\n",
ep->ep_num, ep->opened);

- if (!--ep->iface_ref->opened &&
+ if (ep->iface_ref && !--ep->iface_ref->opened &&
!(chip->quirk_flags & QUIRK_FLAG_IFACE_SKIP_CLOSE))
endpoint_set_interface(chip, ep, false);

--
2.25.1