Messages in this thread Patch in this message | | | From | Jiri Slaby <> | Subject | [PATCH 3.12 097/206] media: v4l2-common: fix overflow in v4l_bound_align_image() | Date | Tue, 18 Nov 2014 15:07:32 +0100 |
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From: Maciej Matraszek <m.matraszek@samsung.com>
3.12-stable review patch. If anyone has any objections, please let me know.
===============
commit 3bacc10cd4a85bc70bc0b6c001d3bf995c7fe04c upstream.
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> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz> --- drivers/media/v4l2-core/v4l2-common.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-)
diff --git a/drivers/media/v4l2-core/v4l2-common.c b/drivers/media/v4l2-core/v4l2-common.c index 037d7a55aa8c..767abc9e5581 100644 --- a/drivers/media/v4l2-core/v4l2-common.c +++ b/drivers/media/v4l2-core/v4l2-common.c @@ -431,16 +431,13 @@ 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; } -- 2.1.3
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