linux-kernel - [PATCH 4.9 055/129] ALSA: usb-audio: Skip bSynchAddress endpoint check if it is invalid

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20191003154342.358817712@linuxfoundation.org>
Date:   Thu,  3 Oct 2019 17:52:58 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Ard van Breemen <ard@...ak.net>,
        Takashi Iwai <tiwai@...e.de>, Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.9 055/129] ALSA: usb-audio: Skip bSynchAddress endpoint check if it is invalid

From: Ard van Breemen <ard@...ak.net>

[ Upstream commit 1b34121d9f26d272b0b2334209af6b6fc82d4bf1 ]

The Linux kernel assumes that get_endpoint(alts,0) and
get_endpoint(alts,1) are eachothers feedback endpoints.
To reassure that validity it will test bsynchaddress to comply with that
assumption. But if the bsyncaddress is 0 (invalid), it will flag that as
a wrong assumption and return an error.
Fix: Skip the test if bSynchAddress is 0.
Note: those with a valid bSynchAddress should have a code quirck added.

Signed-off-by: Ard van Breemen <ard@...ak.net>
Signed-off-by: Takashi Iwai <tiwai@...e.de>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 sound/usb/pcm.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index 497bad9f27898..9bc995f9b4e17 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -470,6 +470,7 @@ static int set_sync_endpoint(struct snd_usb_substream *subs,
 	}
 	ep = get_endpoint(alts, 1)->bEndpointAddress;
 	if (get_endpoint(alts, 0)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
+	    get_endpoint(alts, 0)->bSynchAddress != 0 &&
 	    ((is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress | USB_DIR_IN)) ||
 	     (!is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress & ~USB_DIR_IN)))) {
 		dev_err(&dev->dev,
-- 
2.20.1