zram: fix potential UAF of zram table

If zram_meta_alloc failed early, it frees allocated zram->table without
setting it NULL.  Which will potentially cause zram_meta_free to access
the table if user reset an failed and uninitialized device.

Link: https://lkml.kernel.org/r/20250107065446.86928-1-ryncsn@gmail.com
Fixes: 74363ec674cb ("zram: fix uninitialized ZRAM not releasing backing device")
Signed-off-by: Kairui Song <kasong@tencent.com>
Reviewed-by:  Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 45df5eeabc5e3df07ad8525a6b33813f0bb49749..7903a4da40acfb02aba7a7f5aee49d162965350f 100644 (file)
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1468,6 +1468,7 @@ static bool zram_meta_alloc(struct zram *zram, u64 disksize)
        zram->mem_pool = zs_create_pool(zram->disk->disk_name);
        if (!zram->mem_pool) {
                vfree(zram->table);
+               zram->table = NULL;
                return false;
        }