net/sunrpc: fix potential memory leaks in rpc_sysfs_xprt_state_change()

The issue happens on some error handling paths. When the function
fails to grab the object `xprt`, it simply returns 0, forgetting to
decrease the reference count of another object `xps`, which is
increased by rpc_sysfs_xprt_kobj_get_xprt_switch(), causing refcount
leaks. Also, the function forgets to check whether `xps` is valid
before using it, which may result in NULL-dereferencing issues.

Fix it by adding proper error handling code when either `xprt` or
`xps` is NULL.

Fixes: 5b7eb78486 ("SUNRPC: take a xprt offline using sysfs")
Signed-off-by: Xin Xiong <xiongx18@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Xin Xiong 2022-08-10 23:29:13 +08:00 committed by David S. Miller
parent 86d2155e48
commit bfc48f1b05

View file

@ -291,8 +291,10 @@ static ssize_t rpc_sysfs_xprt_state_change(struct kobject *kobj,
int offline = 0, online = 0, remove = 0;
struct rpc_xprt_switch *xps = rpc_sysfs_xprt_kobj_get_xprt_switch(kobj);
if (!xprt)
return 0;
if (!xprt || !xps) {
count = 0;
goto out_put;
}
if (!strncmp(buf, "offline", 7))
offline = 1;