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 Signed-off-by: Takashi Iwai tiwai@suse.de --- sound/usb/format.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/sound/usb/format.c b/sound/usb/format.c index 93459ba228d3..9ebc5d202c87 100644 --- a/sound/usb/format.c +++ b/sound/usb/format.c @@ -39,6 +39,8 @@ 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 = 1ULL << format;