From ed070066305551c2bf71b0737fcc5fe3e136aed6 Mon Sep 17 00:00:00 2001 From: Maciej Matraszek Date: Mon, 15 Sep 2014 05:14:48 -0300 Subject: [PATCH] media: v4l2-common: fix overflow in v4l_bound_align_image() 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 Acked-by: Sakari Ailus Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Greg Kroah-Hartman --- 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 3fed63f4e026..ec9a4fa3bc86 100644 --- a/drivers/media/v4l2-core/v4l2-common.c +++ b/drivers/media/v4l2-core/v4l2-common.c @@ -485,16 +485,13 @@ 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; } -- 2.34.1