* [PATCH] media: v4l2-core: only zero-out ioctl-read buffers
@ 2020-01-08 10:00 Arnd Bergmann
2020-01-08 10:10 ` Sakari Ailus
0 siblings, 1 reply; 2+ messages in thread
From: Arnd Bergmann @ 2020-01-08 10:00 UTC (permalink / raw)
To: Mauro Carvalho Chehab, Hans Verkuil, Arnd Bergmann
Cc: syzbot+54fd8cca4b7226c94b8e, Sakari Ailus, Ezequiel Garcia,
Vandana BN, Boris Brezillon, linux-media, linux-kernel
The memset() got moved out of the check for _IOC_NONE, so passing a
made-up command number with a size but no direction would allow clearing
data on user-provided pointers.
Move video_get_user() back into the _IOC_NONE check where it belongs.
Reported-by: syzbot+54fd8cca4b7226c94b8e@syzkaller.appspotmail.com
Fixes: 6c625c01c7a6 ("media: v4l2-core: split out data copy from video_usercopy")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
drivers/media/v4l2-core/v4l2-ioctl.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
index b0d670715c27..0f11fc6b5447 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -3208,12 +3208,12 @@ video_usercopy(struct file *file, unsigned int orig_cmd, unsigned long arg,
parg = mbuf;
}
+ err = video_get_user((void __user *)arg, parg, orig_cmd,
+ &always_copy);
+ if (err)
+ goto out;
}
- err = video_get_user((void __user *)arg, parg, orig_cmd, &always_copy);
- if (err)
- goto out;
-
err = check_array_args(cmd, parg, &array_size, &user_ptr, &kernel_ptr);
if (err < 0)
goto out;
--
2.20.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] media: v4l2-core: only zero-out ioctl-read buffers
2020-01-08 10:00 [PATCH] media: v4l2-core: only zero-out ioctl-read buffers Arnd Bergmann
@ 2020-01-08 10:10 ` Sakari Ailus
0 siblings, 0 replies; 2+ messages in thread
From: Sakari Ailus @ 2020-01-08 10:10 UTC (permalink / raw)
To: Arnd Bergmann
Cc: Mauro Carvalho Chehab, Hans Verkuil, syzbot+54fd8cca4b7226c94b8e,
Ezequiel Garcia, Vandana BN, Boris Brezillon, linux-media,
linux-kernel
On Wed, Jan 08, 2020 at 11:00:00AM +0100, Arnd Bergmann wrote:
> The memset() got moved out of the check for _IOC_NONE, so passing a
> made-up command number with a size but no direction would allow clearing
> data on user-provided pointers.
>
> Move video_get_user() back into the _IOC_NONE check where it belongs.
>
> Reported-by: syzbot+54fd8cca4b7226c94b8e@syzkaller.appspotmail.com
> Fixes: 6c625c01c7a6 ("media: v4l2-core: split out data copy from video_usercopy")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Thanks for the fix, Arnd!
Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> ---
> drivers/media/v4l2-core/v4l2-ioctl.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
> index b0d670715c27..0f11fc6b5447 100644
> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> @@ -3208,12 +3208,12 @@ video_usercopy(struct file *file, unsigned int orig_cmd, unsigned long arg,
> parg = mbuf;
> }
>
> + err = video_get_user((void __user *)arg, parg, orig_cmd,
> + &always_copy);
> + if (err)
> + goto out;
> }
>
> - err = video_get_user((void __user *)arg, parg, orig_cmd, &always_copy);
> - if (err)
> - goto out;
> -
> err = check_array_args(cmd, parg, &array_size, &user_ptr, &kernel_ptr);
> if (err < 0)
> goto out;
--
Sakari Ailus
sakari.ailus@linux.intel.com
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2020-01-08 10:10 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-01-08 10:00 [PATCH] media: v4l2-core: only zero-out ioctl-read buffers Arnd Bergmann
2020-01-08 10:10 ` Sakari Ailus
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).