From: Richard Weinberger <richard@nod.at>
Date: Tue, 22 Sep 2015 21:58:07 +0000 (+0200)
Subject: UBI: Validate data_size
X-Git-Tag: v3.2.73~53
X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=commitdiff_plain;h=73d95e7b04162376761b6c942d74cd18b1556dce

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>
[bwh: Backported to 3.2: drop first argument to ubi_err()]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

diff --git a/drivers/mtd/ubi/io.c b/drivers/mtd/ubi/io.c
index f20b6f22f240..6e7f4d45bc0c 100644
--- a/drivers/mtd/ubi/io.c
+++ b/drivers/mtd/ubi/io.c
@@ -943,6 +943,11 @@ static int validate_vid_hdr(const struct ubi_device *ubi,
 		goto bad;
 	}
 
+	if (data_size > ubi->leb_size) {
+		ubi_err("bad data_size");
+		goto bad;
+	}
+
 	if (vol_type == UBI_VID_STATIC) {
 		/*
 		 * Although from high-level point of view static volumes may