Hi Mauro,
On Sunday 11 December 2011 11:22:29 Mauro Carvalho Chehab wrote:
> On 29-11-2011 23:22, Laurent Pinchart wrote:
> > Hi Haogang,
> >
> > On Tuesday 29 November 2011 22:32:25 Haogang Chen wrote:
> >> There is a potential integer overflow in uvc_ioctl_ctrl_map(). When a
> >> large xmap->menu_count is passed from the userspace, the subsequent call
> >> to kmalloc() will allocate a buffer smaller than expected.
> >> map->menu_count and map->menu_info would later be used in a loop (e.g.
> >> in uvc_query_v4l2_ctrl), which leads to out-of-bound access.
> >>
> >> The patch checks the ioctl argument and returns -EINVAL for zero or too
> >> large values in xmap->menu_count.
> >
> > Thanks for the patch.
>
> I'm assuming that either one of you will re-send the patches with the
> pointed changes, so, I'm marking this one with "changes requested" at
> patchwork.
The modified patch is included in my latest pull request.
I had forgotten to CC sta...@kernel.org in the commit message. I've updated
the uvcvideo-next branch, but have you already pulled from it ? If so, could
you add Cc: sta...@kernel.org to the patch, or should I send a v2 for the pull
request ?
> >> Signed-off-by: Haogang Chen<haogangc...@gmail.com>
> >> ---
> >>
> >> drivers/media/video/uvc/uvc_v4l2.c | 6 ++++++
> >> 1 files changed, 6 insertions(+), 0 deletions(-)
> >>
> >> diff --git a/drivers/media/video/uvc/uvc_v4l2.c
> >> b/drivers/media/video/uvc/uvc_v4l2.c index dadf11f..9a180d6 100644
> >> --- a/drivers/media/video/uvc/uvc_v4l2.c
> >> +++ b/drivers/media/video/uvc/uvc_v4l2.c
> >> @@ -58,6 +58,12 @@ static int uvc_ioctl_ctrl_map(struct uvc_video_chain
> >> *chain, break;
> >>
> >> case V4L2_CTRL_TYPE_MENU:
> >> + if (xmap->menu_count == 0 ||
> >> + xmap->menu_count> INT_MAX / sizeof(*map->menu_info)) {
> >
> > I'd like to prevent excessive memory consumption by limiting the number
> > of menu entries, similarly to how the driver limits the number of
> > mappings. Defining UVC_MAX_CONTROL_MENU_ENTRIES to 32 in uvcvideo.h
> > should be a reasonable value.
> >
> >> + kfree(map);
> >> + return -EINVAL;
> >
> > I'd rather do
> >
> > ret = -EINVAL;
> > goto done;
> >
> > to centralize error handling.
> >
> > If you're fine with both changes I can modify the patch, there's no need
> > to resubmit.
> >
> >> + }
> >> +
> >>
> >> size = xmap->menu_count * sizeof(*map->menu_info);
> >> map->menu_info = kmalloc(size, GFP_KERNEL);
> >> if (map->menu_info == NULL) {
--
Regards,
Laurent Pinchart
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