[PATCH] zram: fix potential UAF of zram table

From: Kairui Song
Date: Tue Jan 07 2025 - 01:55:08 EST


From: Kairui Song <kasong@xxxxxxxxxxx>

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.

Fixes: 74363ec674cb ("zram: fix uninitialized ZRAM not releasing backing device")
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Kairui Song <kasong@xxxxxxxxxxx>
---
drivers/block/zram/zram_drv.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 5b8e4f4171ab..70ecaee25c20 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1465,6 +1465,7 @@ 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;
}

--
2.47.1