From: Arnd Bergmann <arnd@kernel.org>
To: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Linux Media Mailing List <linux-media@vger.kernel.org>,
syzbot <syzbot+1115e79c8df6472c612b@syzkaller.appspotmail.com>,
Arnd Bergmann <arnd@arndb.de>,
Hans Verkuil <hverkuil-cisco@xs4all.nl>,
Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Mauro Carvalho Chehab <mchehab@kernel.org>,
syzkaller-bugs <syzkaller-bugs@googlegroups.com>
Subject: Re: [PATCH 1/1] v4l: ioctl: Fix memory leak in video_usercopy
Date: Sun, 20 Dec 2020 12:36:23 +0100 [thread overview]
Message-ID: <CAK8P3a3s=yU=PW7zLc4M83DksxAsb=v8r4U6aAySj2-nmeczjA@mail.gmail.com> (raw)
In-Reply-To: <20201220110651.13432-1-sakari.ailus@linux.intel.com>
On Sun, Dec 20, 2020 at 12:06 PM Sakari Ailus
<sakari.ailus@linux.intel.com> wrote:
>
> When an IOCTL with argument size larger than 128 that also used array
> arguments were handled, two memory allocations were made but alas, only
> the latter one of them was released. This happened because there was only
> a single local variable to hold such a temporary allocation.
>
> Fix this by adding separate variables to hold the pointers to the
> temporary allocations.
>
> Reported-by: Arnd Bergmann <arnd@kernel.org>
> Reported-by: syzbot+1115e79c8df6472c612b@syzkaller.appspotmail.com
> Fixes: d14e6d76ebf7 ("[media] v4l: Add multi-planar ioctl handling code")
> Cc: stable@vger.kernel.org
> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
> out:
> + kvfree(array_buf);
> kvfree(mbuf);
I think it would make sense to change mbuf back to kzalloc()/kfree
after this, since the size of the ioctl argument has an upper bound
of 2^_IOC_SIZEBITS (16KB), which does not need the vmalloc
path, unlike the array args.
Arnd
next prev parent reply other threads:[~2020-12-20 11:37 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-20 11:06 [PATCH 1/1] v4l: ioctl: Fix memory leak in video_usercopy Sakari Ailus
2020-12-20 11:09 ` Hans Verkuil
2020-12-20 11:36 ` Arnd Bergmann [this message]
2020-12-20 11:51 ` Sakari Ailus
2020-12-20 14:15 ` Laurent Pinchart
2020-12-20 20:03 ` Sakari Ailus
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