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Commit b5f6bf0f authored by Coly Li's avatar Coly Li Committed by Greg Kroah-Hartman
Browse files

bcache: fix use-after-free in register_bcache() 



[ 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: default avatarColy Li <colyli@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 393b8509

drivers/md/bcache/super.c

+2 −1
Original line number Diff line number Diff line
@@ -2472,10 +2472,11 @@ 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;

}