iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

[media] v4l2-common: fix overflow in v4l_bound_align_image()

Browse Source 
Fix clamp_align() used in v4l_bound_align_image() to prevent overflow
when passed large value like UINT32_MAX.

 In the current implementation:
    clamp_align(UINT32_MAX, 8, 8192, 3)

returns 8, because in line:

    x = (x + (1 << (align - 1))) & mask;

x overflows to (-1 + 4) & 0x7 = 3, while expected value is 8192.

v4l_bound_align_image() is heavily used in VIDIOC_S_FMT and
VIDIOC_SUBDEV_S_FMT ioctls handlers, and documentation of the latter
explicitly states that:

"The modified format should be as close as possible to the original
request."
  -- http://linuxtv.org/downloads/v4l-dvb-apis/vidioc-subdev-g-fmt.html

Thus one would expect, that passing UINT32_MAX as format width and
height will result in setting maximum possible resolution for the
device. Particularly, when the driver doesn't support
VIDIOC_ENUM_FRAMESIZES ioctl, which is common in the codebase.

Fixes changeset: b0d3159be9a3

Signed-off-by: Maciej Matraszek <m.matraszek@samsung.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
This commit is contained in:
Maciej Matraszek 2014-09-15 05:14:48 -03:00 committed by Mauro Carvalho Chehab
parent 43c3ea312c
commit 3bacc10cd4
1 changed files with 3 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
drivers/media/v4l2-core/v4l2-common.c
View File

@ -435,16 +435,13 @@ static unsigned int clamp_align(unsigned int x, unsigned int min,
/* Bits that must be zero to be aligned */
unsigned int mask = ~((1 << align) - 1);
/* Clamp to aligned min and max */
x = clamp(x, (min + ~mask) & mask, max & mask);
/* Round to nearest aligned value */
if (align)
x = (x + (1 << (align - 1))) & mask;
/* Clamp to aligned value of min and max */
if (x < min)
x = (min + ~mask) & mask;
else if (x > max)
x = max & mask;
return x;
}