From: Takashi Iwai <tiwai@xxxxxxx> 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@xxxxxxxxxxxxxxxxxxxxxxxxx Cc: <stable@xxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20201209084552.17109-1-tiwai@xxxxxxx Signed-off-by: Takashi Iwai <tiwai@xxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- sound/usb/format.c | 2 ++ 1 file changed, 2 insertions(+) --- a/sound/usb/format.c +++ b/sound/usb/format.c @@ -40,6 +40,8 @@ static u64 parse_audio_format_i_type(str 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;
