[ 113/184] fs/compat_ioctl.c: VIDEO_SET_SPU_PALETTE missing

[Willy Tarreau]

2.6.32-longterm review patch.  If anyone has any objections, please let me know.

------------------
 error check

From: Kees Cook <keescook@xxxxxxxxxxxx>

commit 12176503366885edd542389eed3aaf94be163fdb upstream.

The compat ioctl for VIDEO_SET_SPU_PALETTE was missing an error check
while converting ioctl arguments.  This could lead to leaking kernel
stack contents into userspace.

Patch extracted from existing fix in grsecurity.

Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: David Miller <davem@xxxxxxxxxxxxx>
Cc: Brad Spengler <spender@xxxxxxxxxxxxxx>
Cc: PaX Team <pageexec@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Willy Tarreau <w@xxxxxx>
---
 fs/compat_ioctl.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/compat_ioctl.c b/fs/compat_ioctl.c
index d84e705..0dd21a4 100644
--- a/fs/compat_ioctl.c
+++ b/fs/compat_ioctl.c
@@ -234,6 +234,8 @@ static int do_video_set_spu_palette(unsigned int fd, unsigned int cmd, unsigned
 	up = (struct compat_video_spu_palette __user *) arg;
 	err  = get_user(palp, &up->palette);
 	err |= get_user(length, &up->length);
+	if (err)
+		return -EFAULT;
 
 	up_native = compat_alloc_user_space(sizeof(struct video_spu_palette));
 	err  = put_user(compat_ptr(palp), &up_native->palette);
-- 
1.7.12.2.21.g234cd45.dirty



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