[PATCH 3.12 072/123] UBI: Validate data_size

[Jiri Slaby]

From: Richard Weinberger <richard@xxxxxx>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

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@xxxxxx>
Reviewed-by: David Gstir <david@xxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
 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 bf79def40126..8822e880833b 100644
--- a/drivers/mtd/ubi/io.c
+++ b/drivers/mtd/ubi/io.c
@@ -931,6 +931,11 @@ 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
-- 
2.6.2

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