net/sunrpc: fix reference count leaks in rpc_sysfs_xprt_state_change

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: net/sunrpc: fix reference count leaks in rpc_sysfs_xprt_state_change The refcount leak issues take place in an error handling path. When the 3rd argument buf doesn't match with "offline", "online" or "remove", the function simply returns -EINVAL and forgets to decrease the reference count of a rpc_xprt object and a rpc_xprt_switch object increased by rpc_sysfs_xprt_kobj_get_xprt() and rpc_sysfs_xprt_kobj_get_xprt_switch(), causing reference count leaks of both unused objects. Fix this issue by jumping to the error handling path labelled with out_put when buf matches none of "offline", "online" or "remove".

References

• https://git.kernel.org/stable/c/4b22aa42bd4d2d630ef1854c139275c3532937cb
• https://git.kernel.org/stable/c/5f6024c05a2c0fdd180b29395aaf686d25af3a0f
• https://git.kernel.org/stable/c/776d794f28c95051bc70405a7b1fa40115658a18