mtd: virt_concat: fix use-after-free in mtd_virt_concat_destroy_joins()

mtd_concat_destroy() frees item->concat so calling
mtd_virt_concat_put_mtd_devices(item->concat) leads to a use after free.

Fix this by moving mtd_virt_concat_put_mtd_devices() before
mtd_concat_destroy()

Fixes: 43db6366fc2d ("mtd: Add driver for concatenating devices")
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

diff --git a/drivers/mtd/mtd_virt_concat.c b/drivers/mtd/mtd_virt_concat.c
index 37075ead0f3377b601c616400496f26f0521917d..a3fb96788e9dc8b2bbd1a9a55687f4b4c9579fbe 100644 (file)
--- a/drivers/mtd/mtd_virt_concat.c
+++ b/drivers/mtd/mtd_virt_concat.c
@@ -75,8 +75,8 @@ void mtd_virt_concat_destroy_joins(void)
                if (item->concat) {
                        mtd_device_unregister(mtd);
                        kfree(mtd->name);
-                       mtd_concat_destroy(mtd);
                        mtd_virt_concat_put_mtd_devices(item->concat);
+                       mtd_concat_destroy(mtd);
                }
        }
 }