3.16.55-rc1 review patch. If anyone has any objections, please let me know.
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From: Guennadi Liakhovetski g.liakhovetski@gmx.de
commit 6ed9b28504326f8cf542e6b68245b2f7ce009216 upstream.
Similar to an earlier patch, fixing reading user-space data for the VIDIOC_CREATE_BUFS ioctl() in 32-bit compatibility mode, this patch fixes writing back of the possibly modified struct to the user. However, unlike the former bug, this one is much less harmful, because it only results in the kernel failing to write the .type field back to the user, but in fact this is likely unneeded, because the kernel will hardly want to change that field. Therefore this bug is more of a theoretical nature.
Signed-off-by: Guennadi Liakhovetski g.liakhovetski@gmx.de Acked-by: Laurent Pinchart laurent.pinchart@ideasonboard.com Signed-off-by: Mauro Carvalho Chehab mchehab@osg.samsung.com Signed-off-by: Ben Hutchings ben@decadent.org.uk --- drivers/media/v4l2-core/v4l2-compat-ioctl32.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
--- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c +++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c @@ -222,6 +222,9 @@ static int get_v4l2_create32(struct v4l2
static int __put_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user *up) { + if (put_user(kp->type, &up->type)) + return -EFAULT; + switch (kp->type) { case V4L2_BUF_TYPE_VIDEO_CAPTURE: case V4L2_BUF_TYPE_VIDEO_OUTPUT: @@ -248,8 +251,7 @@ static int __put_v4l2_format32(struct v4
static int put_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user *up) { - if (!access_ok(VERIFY_WRITE, up, sizeof(struct v4l2_format32)) || - put_user(kp->type, &up->type)) + if (!access_ok(VERIFY_WRITE, up, sizeof(struct v4l2_format32))) return -EFAULT; return __put_v4l2_format32(kp, up); } @@ -257,8 +259,8 @@ static int put_v4l2_format32(struct v4l2 static int put_v4l2_create32(struct v4l2_create_buffers *kp, struct v4l2_create_buffers32 __user *up) { if (!access_ok(VERIFY_WRITE, up, sizeof(struct v4l2_create_buffers32)) || - copy_to_user(up, kp, offsetof(struct v4l2_create_buffers32, format.fmt))) - return -EFAULT; + copy_to_user(up, kp, offsetof(struct v4l2_create_buffers32, format))) + return -EFAULT; return __put_v4l2_format32(&kp->format, &up->format); }