From: Coly Li <colyli@xxxxxxx>
[ Upstream commit ae3cd299919af6eb670d5af0bc9d7ba14086bd8e ]
The patch "bcache: rework error unwinding in register_bcache" introduces
a use-after-free regression in register_bcache(). Here are current code,
2510 out_free_path:
2511 kfree(path);
2512 out_module_put:
2513 module_put(THIS_MODULE);
2514 out:
2515 pr_info("error %s: %s", path, err);
2516 return ret;
If some error happens and the above code path is executed, at line 2511
path is released, but referenced at line 2515. Then KASAN reports a use-
after-free error message.
This patch changes line 2515 in the following way to fix the problem,
2515 pr_info("error %s: %s", path?path:"", err);
Signed-off-by: Coly Li <colyli@xxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/md/bcache/super.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index bd2ae1d78fe15..05cb94664efee 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -2475,10 +2475,11 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
kfree(sb);
out_free_path:
kfree(path);
+ path = NULL;
out_module_put:
module_put(THIS_MODULE);
out:
- pr_info("error %s: %s", path, err);
+ pr_info("error %s: %s", path?path:"", err);
return ret;
}
--
2.20.1
