diff options
authorGuennadi Liakhovetski <g.liakhovetski@gmx.de>2014-04-26 12:51:31 -0300
committerMauro Carvalho Chehab <m.chehab@samsung.com>2014-05-13 20:00:28 -0300
commitec77581a6ca0be566bf3428263820da6d12ed5ae (patch)
parent322e6d19ede96ac6c13a132590c435ff17e0827f (diff)
[media] V4L2: fix VIDIOC_CREATE_BUFS in 64- / 32-bit compatibility mode
If a struct contains 64-bit fields, it is aligned on 64-bit boundaries within containing structs in 64-bit compilations. This is the case with struct v4l2_window, which contains pointers and is embedded into struct v4l2_format, and that one is embedded into struct v4l2_create_buffers. Unlike some other structs, used as a part of the kernel ABI as ioctl() arguments, that are packed, these structs aren't packed. This isn't a problem per se, but the ioctl-compat code for VIDIOC_CREATE_BUFS contains a bug, that triggers in such 64-bit builds. That code wrongly assumes, that in struct v4l2_create_buffers, struct v4l2_format immediately follows the __u32 memory field, which in fact isn't the case. This bug wasn't visible until now, because until recently hardly any applications used this ioctl() and mostly embedded 32-bit only drivers implemented it. This is changing now with addition of this ioctl() to some USB drivers, e.g. UVC. This patch fixes the bug by copying parts of struct v4l2_create_buffers separately. Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
1 files changed, 7 insertions, 5 deletions
diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
index 04b2daf567be..7e2411c36419 100644
--- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
+++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
@@ -178,6 +178,9 @@ struct v4l2_create_buffers32 {
static int __get_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user *up)
+ if (get_user(kp->type, &up->type))
+ return -EFAULT;
switch (kp->type) {
@@ -204,17 +207,16 @@ static int __get_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __us
static int get_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user *up)
- if (!access_ok(VERIFY_READ, up, sizeof(struct v4l2_format32)) ||
- get_user(kp->type, &up->type))
- return -EFAULT;
+ if (!access_ok(VERIFY_READ, up, sizeof(struct v4l2_format32)))
+ return -EFAULT;
return __get_v4l2_format32(kp, up);
static int get_v4l2_create32(struct v4l2_create_buffers *kp, struct v4l2_create_buffers32 __user *up)
if (!access_ok(VERIFY_READ, up, sizeof(struct v4l2_create_buffers32)) ||
- copy_from_user(kp, up, offsetof(struct v4l2_create_buffers32, format.fmt)))
- return -EFAULT;
+ copy_from_user(kp, up, offsetof(struct v4l2_create_buffers32, format)))
+ return -EFAULT;
return __get_v4l2_format32(&kp->format, &up->format);

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