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authorTakashi Iwai <tiwai@suse.de>2020-12-09 09:45:51 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-12-29 13:46:46 +0100
commitb5ac73ed84d634a0ba528435ffaeefa2a81f2253 (patch)
tree7a925263e3aad722dcb4522bbeb8e6189e39167b /sound/usb
parent230f33f3cb954aacadc2cb90396f10269129b19c (diff)
downloadlinux-rt-b5ac73ed84d634a0ba528435ffaeefa2a81f2253.tar.gz
ALSA: usb-audio: Fix potential out-of-bounds shift
commit 43d5ca88dfcd35e43010fdd818e067aa9a55f5ba upstream. syzbot spotted a potential out-of-bounds shift in the USB-audio format parser that receives the arbitrary shift value from the USB descriptor. Add a range check for avoiding the undefined behavior. Reported-by: syzbot+df7dc146ebdd6435eea3@syzkaller.appspotmail.com Cc: <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20201209084552.17109-1-tiwai@suse.de Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'sound/usb')
-rw-r--r--sound/usb/format.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/sound/usb/format.c b/sound/usb/format.c
index eeb56d6fe8aa..06190e3fd919 100644
--- a/sound/usb/format.c
+++ b/sound/usb/format.c
@@ -52,6 +52,8 @@ static u64 parse_audio_format_i_type(struct snd_usb_audio *chip,
case UAC_VERSION_1:
default: {
struct uac_format_type_i_discrete_descriptor *fmt = _fmt;
+ if (format >= 64)
+ return 0; /* invalid format */
sample_width = fmt->bBitResolution;
sample_bytes = fmt->bSubframeSize;
format = 1 << format;