From: Kees Cook <keescook@chromium.org>
Date: Thu, 25 Oct 2012 20:38:16 +0000 (-0700)
Subject: fs/compat_ioctl.c: VIDEO_SET_SPU_PALETTE missing error check
X-Git-Tag: v2.6.34.15~56
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=fabe66bd6a4683f802b3cc6ec59579effb1afc41;p=thirdparty%2Fkernel%2Fstable.git

fs/compat_ioctl.c: VIDEO_SET_SPU_PALETTE missing error check

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@chromium.org>
Cc: David Miller <davem@davemloft.net>
Cc: Brad Spengler <spender@grsecurity.net>
Cc: PaX Team <pageexec@freemail.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---

diff --git a/fs/compat_ioctl.c b/fs/compat_ioctl.c
index 641640dc7ae54..7a00d9b155bf9 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);