| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.4 289/344] bcache: fix use-after-free in register_bcache() | Date | Fri, 21 Feb 2020 08:41:28 +0100 |
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From: Coly Li <colyli@suse.de>
[ 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@suse.de> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org> --- 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 86f7e09d31516..485ebc2b2144c 100644 --- a/drivers/md/bcache/super.c +++ b/drivers/md/bcache/super.c @@ -2472,10 +2472,11 @@ out_free_sb: 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
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