ubi: Fix out of bounds write in volume update code

ubi_start_leb_change() allocates too few bytes.
ubi_more_leb_change_data() will write up to req->upd_bytes +
ubi->min_io_size bytes.

Cc: stable@vger.kernel.org
Signed-off-by: Richard Weinberger <richard@nod.at>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>

diff --git a/drivers/mtd/ubi/upd.c b/drivers/mtd/ubi/upd.c
index 2a1b6e0..0134ba3 100644 (file)
--- 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;