From: Coly Li colyli@suse.de
mainline inclusion from mainline-5.6-rc1 commit ae3cd299919af6eb670d5af0bc9d7ba14086bd8e category: feature bugzilla: 43003 CVE: NA ---------------------------
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 Acked-by: Hanjun Guo guohanjun@huawei.com Reviewed-by: Yufen Yu yuyufen@huawei.com Signed-off-by: zhangyi (F) yi.zhang@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- 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 a5bbaf0c047a..d0c19f9dcbdc 100644 --- a/drivers/md/bcache/super.c +++ b/drivers/md/bcache/super.c @@ -2470,10 +2470,11 @@ 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; }