[3.16.y-ckt stable] Patch "UBI: Validate data_size" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    UBI: Validate data_size

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt19.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 80fe92d4075b6b72a371b7bfa4093f2bfa02f321 Mon Sep 17 00:00:00 2001
From: Richard Weinberger <richard at 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 at nod.at>
Reviewed-by: David Gstir <david at sigma-star.at>
[ luis: backported to 3.16:
  - no ubi_device parameter for the ubi_err() macro in 3.16 ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/mtd/ubi/io.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/mtd/ubi/io.c b/drivers/mtd/ubi/io.c
index d36134925d31..db657f2168d7 100644
--- a/drivers/mtd/ubi/io.c
+++ b/drivers/mtd/ubi/io.c
@@ -921,6 +921,11 @@ 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