CVE-2025-38724

In the Linux kernel, the following vulnerability has been resolved:

nfsd: handle getclientlocked() failure in nfsd4setclientidconfirm()

Lei Lu recently reported that nfsd4setclientidconfirm() did not check the return value from getclientlocked(). a SETCLIENTID_CONFIRM could race with a confirmed client expiring and fail to get a reference. That could later lead to a UAF.

Fix this by getting a reference early in the case where there is an extant confirmed client. If that fails then treat it as if there were no confirmed client found at all.

In the case where the unconfirmed client is expiring, just fail and return the result from getclientlocked().