linux-kernel - [PATCH AUTOSEL 4.14 099/130] media: pvrusb2: Fix oops on tear-down when radio support is not present

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: <20191210220301.13262-99-sashal@kernel.org>
Date:   Tue, 10 Dec 2019 17:02:30 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Mike Isely <isely@...ox.com>,
        Hans Verkuil <hverkuil-cisco@...all.nl>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Sasha Levin <sashal@...nel.org>, linux-media@...r.kernel.org
Subject: [PATCH AUTOSEL 4.14 099/130] media: pvrusb2: Fix oops on tear-down when radio support is not present

From: Mike Isely <isely@...ox.com>

[ Upstream commit 7f404ae9cf2a285f73b3c18ab9303d54b7a3d8e1 ]

In some device configurations there's no radio or radio support in the
driver.  That's OK, as the driver sets itself up accordingly.  However
on tear-down in these caes it's still trying to tear down radio
related context when there isn't anything there, leading to
dereferences through a null pointer and chaos follows.

How this bug survived unfixed for 11 years in the pvrusb2 driver is a
mystery to me.

[hverkuil: fix two checkpatch warnings]

Signed-off-by: Mike Isely <isely@...ox.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@...all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/media/usb/pvrusb2/pvrusb2-v4l2.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/media/usb/pvrusb2/pvrusb2-v4l2.c b/drivers/media/usb/pvrusb2/pvrusb2-v4l2.c
index 4320bda9352df..e0413db267816 100644
--- a/drivers/media/usb/pvrusb2/pvrusb2-v4l2.c
+++ b/drivers/media/usb/pvrusb2/pvrusb2-v4l2.c
@@ -915,8 +915,12 @@ static void pvr2_v4l2_internal_check(struct pvr2_channel *chp)
 	pvr2_v4l2_dev_disassociate_parent(vp->dev_video);
 	pvr2_v4l2_dev_disassociate_parent(vp->dev_radio);
 	if (!list_empty(&vp->dev_video->devbase.fh_list) ||
-	    !list_empty(&vp->dev_radio->devbase.fh_list))
+	    (vp->dev_radio &&
+	     !list_empty(&vp->dev_radio->devbase.fh_list))) {
+		pvr2_trace(PVR2_TRACE_STRUCT,
+			   "pvr2_v4l2 internal_check exit-empty id=%p", vp);
 		return;
+	}
 	pvr2_v4l2_destroy_no_lock(vp);
 }
 
@@ -990,7 +994,8 @@ static int pvr2_v4l2_release(struct file *file)
 	kfree(fhp);
 	if (vp->channel.mc_head->disconnect_flag &&
 	    list_empty(&vp->dev_video->devbase.fh_list) &&
-	    list_empty(&vp->dev_radio->devbase.fh_list)) {
+	    (!vp->dev_radio ||
+	     list_empty(&vp->dev_radio->devbase.fh_list))) {
 		pvr2_v4l2_destroy_no_lock(vp);
 	}
 	return 0;
-- 
2.20.1