Commit 37958ac3 authored Mar 24, 2023 by Takashi Iwai Committed by Greg Kroah-Hartman Apr 05, 2023

ALSA: usb-audio: Fix regression on detection of Roland VS-100

commit fa4e7a6fa12b1132340785e14bd439cbe95b7a5a upstream.

It's been reported that the recent kernel can't probe the PCM devices
on Roland VS-100 properly, and it turned out to be a regression by the
recent addition of the bit shift range check for the format bits.
In the old code, we just did bit-shift and it resulted in zero, which
is then corrected to the standard PCM format, while the new code
explicitly returns an error in such a case.

For addressing the regression, relax the check and fallback to the
standard PCM type (with the info output).

Fixes: 43d5ca88dfcd ("ALSA: usb-audio: Fix potential out-of-bounds shift")
Cc: <stable@vger.kernel.org>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=217084
Link: https://lore.kernel.org/r/20230324075005.19403-1-tiwai@suse.de


Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 6dabafd8

sound/usb/format.c

+6 −2

Original line number	Original line	Diff line number	Diff line
	@@ -40,8 +40,12 @@ static u64 parse_audio_format_i_type(struct snd_usb_audio *chip,
	case UAC_VERSION_1:		case UAC_VERSION_1:
	default: {		default: {
	struct uac_format_type_i_discrete_descriptor *fmt = _fmt;		struct uac_format_type_i_discrete_descriptor *fmt = _fmt;
	if (format >= 64)		if (format >= 64) {
	return 0; /* invalid format */		usb_audio_info(chip,
			"%u:%d: invalid format type 0x%llx is detected, processed as PCM\n",
			fp->iface, fp->altsetting, format);
			format = UAC_FORMAT_TYPE_I_PCM;
			}
	sample_width = fmt->bBitResolution;		sample_width = fmt->bBitResolution;
	sample_bytes = fmt->bSubframeSize;		sample_bytes = fmt->bSubframeSize;
	format = 1ULL << format;		format = 1ULL << format;