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From: Takashi Iwai <tiwai@suse.de>
To: alsa-devel@alsa-project.org
Subject: [alsa-devel] [PATCH 1/2] ALSA: usb-audio: Fix incorrect size check for processing/extension units
Date: Thu, 14 Nov 2019 17:56:12 +0100
Message-ID: <20191114165613.7422-1-tiwai@suse.de> (raw)

The recently introduced unit descriptor validation had some bug for
processing and extension units, it counts a bControlSize byte twice so
it expected a bigger size than it should have been.  This seems
resulting in a probe error on a few devices.

Fix the calculation for proper checks of PU and EU.

Fixes: 57f8770620e9 ("ALSA: usb-audio: More validations of descriptor units")
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 sound/usb/validate.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/sound/usb/validate.c b/sound/usb/validate.c
index a5e584b60dcd..389e8657434a 100644
--- a/sound/usb/validate.c
+++ b/sound/usb/validate.c
@@ -81,9 +81,9 @@ static bool validate_processing_unit(const void *p,
 	switch (v->protocol) {
 	case UAC_VERSION_1:
 	default:
-		/* bNrChannels, wChannelConfig, iChannelNames, bControlSize */
-		len += 1 + 2 + 1 + 1;
-		if (d->bLength < len) /* bControlSize */
+		/* bNrChannels, wChannelConfig, iChannelNames */
+		len += 1 + 2 + 1;
+		if (d->bLength < len + 1) /* bControlSize */
 			return false;
 		m = hdr[len];
 		len += 1 + m + 1; /* bControlSize, bmControls, iProcessing */
-- 
2.16.4

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Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-14 16:56 Takashi Iwai [this message]
2019-11-14 16:56 ` [alsa-devel] [PATCH 2/2] ALSA: usb-audio: Add skip_validation option Takashi Iwai

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