ubi: Fix out of bounds write in volume update code

commit e4f6daac20332448529b11f09388f1d55ef2084c upstream.

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.

Signed-off-by: Richard Weinberger <richard@nod.at>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/mtd/ubi/upd.c b/drivers/mtd/ubi/upd.c
index 068a246..d1802b0 100644 (file)
--- a/drivers/mtd/ubi/upd.c
+++ b/drivers/mtd/ubi/upd.c
@@ -197,7 +197,7 @@ int ubi_start_leb_change(struct ubi_device *ubi, struct ubi_volume *vol,
        vol->ch_lnum = req->lnum;
        vol->ch_dtype = req->dtype;
 
-       vol->upd_buf = vmalloc(req->bytes);
+       vol->upd_buf = vmalloc(ALIGN((int)req->bytes, ubi->min_io_size));
        if (!vol->upd_buf)
                return -ENOMEM;