From: Takashi Iwai tiwai@suse.de
stable inclusion from stable-5.10.2 commit cc3edd81ef035b728955241dca8a3b3c2f333ab6 bugzilla: 46859
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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 --- sound/usb/format.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/sound/usb/format.c b/sound/usb/format.c index 3bfead393aa3..91f0ed4a2e7e 100644 --- a/sound/usb/format.c +++ b/sound/usb/format.c @@ -40,6 +40,8 @@ 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;