From: Kees Cook <keescook@xxxxxxxxxxxx>
-------------------
This is a commit scheduled for the next v2.6.34 longterm release.
http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git
If you see a problem with using this for longterm, please comment.
-------------------
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: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
---
fs/compat_ioctl.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/compat_ioctl.c b/fs/compat_ioctl.c
index 641640dc7ae5..7a00d9b155bf 100644
--- a/fs/compat_ioctl.c
+++ b/fs/compat_ioctl.c
@@ -227,6 +227,8 @@ static int do_video_set_spu_palette(unsigned int fd, unsigned int cmd,
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);
--
1.8.5.2
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