From 281fda27673f833a01d516658a64d22a32c8e072 Mon Sep 17 00:00:00 2001
From: Richard Weinberger <richard@nod.at>
Date: Tue, 22 Sep 2015 23:58:07 +0200
Subject: UBI: Validate data_size

commit 281fda27673f833a01d516658a64d22a32c8e072 upstream.

Make sure that data_size is less than LEB size.
Otherwise a handcrafted UBI image is able to trigger
an out of bounds memory access in ubi_compare_lebs().

Signed-off-by: Richard Weinberger <richard@nod.at>
Reviewed-by: David Gstir <david@sigma-star.at>
[lizf: Backported to 3.4: use dbg_err() instead of ubi_err()];
Signed-off-by: Zefan Li <lizefan@huawei.com>
---
 drivers/mtd/ubi/io.c |    5 +++++
 1 file changed, 5 insertions(+)

--- a/drivers/mtd/ubi/io.c
+++ b/drivers/mtd/ubi/io.c
@@ -942,6 +942,11 @@ static int validate_vid_hdr(const struct
 		goto bad;
 	}
 
+	if (data_size > ubi->leb_size) {
+		dbg_err("bad data_size");
+		goto bad;
+	}
+
 	if (vol_type == UBI_VID_STATIC) {
 		/*
 		 * Although from high-level point of view static volumes may