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From: Pavel Skripkin <paskripkin@gmail.com>
To: mchehab@kernel.org, hverkuil@xs4all.nl
Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
	Pavel Skripkin <paskripkin@gmail.com>,
	syzbot+a6969ef522a36d3344c9@syzkaller.appspotmail.com
Subject: [PATCH v3] media: em28xx: add missing em28xx_close_extension
Date: Thu, 29 Jul 2021 23:23:33 +0300	[thread overview]
Message-ID: <20210729202333.21605-1-paskripkin@gmail.com> (raw)
In-Reply-To: <aa8b3e18-7903-9380-d0d6-2303d09110fe@xs4all.nl>

If em28xx dev has ->dev_next pointer, we need to delete ->dev_next list
node from em28xx_extension_devlist on disconnect to avoid UAF bugs and
corrupted list bugs, since driver frees this pointer on disconnect.

Fixes: 1a23f81b7dc3 ("V4L/DVB (9979): em28xx: move usb probe code to a proper place")
Reported-and-tested-by: syzbot+a6969ef522a36d3344c9@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
---

Changes in v3:
	Changed order of em28xx_close_extension() and
	em28xx_release_resources() as Hans suggested

Changes in v2:
	Previous patch was completely broken. I've done some debugging
	again and found true root case of the reported bug.

---
 drivers/media/usb/em28xx/em28xx-cards.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/media/usb/em28xx/em28xx-cards.c b/drivers/media/usb/em28xx/em28xx-cards.c
index c1e0dccb7408..948e22e29b42 100644
--- a/drivers/media/usb/em28xx/em28xx-cards.c
+++ b/drivers/media/usb/em28xx/em28xx-cards.c
@@ -4139,8 +4139,11 @@ static void em28xx_usb_disconnect(struct usb_interface *intf)
 
 	em28xx_close_extension(dev);
 
-	if (dev->dev_next)
+	if (dev->dev_next) {
+		em28xx_close_extension(dev->dev_next);
 		em28xx_release_resources(dev->dev_next);
+	}
+
 	em28xx_release_resources(dev);
 
 	if (dev->dev_next) {
-- 
2.32.0


      reply	other threads:[~2021-07-29 20:23 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-06 14:50 [PATCH] media: em28xx: fix corrupted list Pavel Skripkin
2021-07-20 12:13 ` Hans Verkuil
2021-07-21 12:21   ` Pavel Skripkin
2021-07-21 12:25     ` Hans Verkuil
2021-07-21 19:43       ` [PATCH v2] media: em28xx: add missing em28xx_close_extension Pavel Skripkin
2021-07-29  9:45         ` Hans Verkuil
2021-07-29 12:45           ` Pavel Skripkin
2021-07-29 13:40             ` Hans Verkuil
2021-07-29 20:23               ` Pavel Skripkin [this message]

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