ALSA: usb-audio: Add sanity check for OOB writes at silencing

Browse source

[ Upstream commit fba2105a15 ]

At silencing the playback URB packets in the implicit fb mode before
the actual playback, we blindly assume that the received packets fit
with the buffer size.  But when the setup in the capture stream
differs from the playback stream (e.g. due to the USB core limitation
of max packet size), such an inconsistency may lead to OOB writes to
the buffer, resulting in a crash.

For addressing it, add a sanity check of the transfer buffer size at
prepare_silent_urb(), and stop the data copy if the received data
overflows.  Also, report back the transfer error properly from there,
too.

Note that this doesn't fix the root cause of the playback error
itself, but this merely covers the kernel Oops.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=221076
Link: https://patch.msgid.link/20260216141209.1849200-4-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

...

This commit is contained in:

Takashi Iwai 2026-02-16 15:12:07 +01:00 • committed by Sasha Levin

parent 5d82acdcc4

commit fa01973bb7

1 changed files with 22 additions and 17 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

37

sound/usb/endpoint.c

View file