From: Maciej Matraszek <m.matraszek@samsung.com>
Date: Mon, 15 Sep 2014 08:14:48 +0000 (-0300)
Subject: [media] v4l2-common: fix overflow in v4l_bound_align_image()
X-Git-Tag: fixes-against-v3.18-rc2~130^2^2~77
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3bacc10cd4a85bc70bc0b6c001d3bf995c7fe04c;p=pandora-kernel.git

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

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>
---

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