ubi: Fix out of bounds write in volume update code

richardweinberger · richardweinberger · commit e4f6daac2033 · 2016-03-05T21:56:23.000+01:00
ubi_start_leb_change() allocates too few bytes.
ubi_more_leb_change_data() will write up to req-&gt;upd_bytes +
ubi-&gt;min_io_size bytes.

Cc: stable@vger.kernel.org
Signed-off-by: Richard Weinberger &lt;richard@nod.at&gt;
Reviewed-by: Boris Brezillon &lt;boris.brezillon@free-electrons.com&gt;
diff --git a/drivers/mtd/ubi/upd.c b/drivers/mtd/ubi/upd.c
@@ -193,7 +193,7 @@ int ubi_start_leb_change(struct ubi_device *ubi, struct ubi_volume *vol,
 	vol->changing_leb = 1;
 	vol->ch_lnum = req->lnum;
 
-	vol->upd_buf = vmalloc(req->bytes);
+	vol->upd_buf = vmalloc(ALIGN((int)req->bytes, ubi->min_io_size));
 	if (!vol->upd_buf)
 		return -ENOMEM;
 
