CVE-2024-56564 ceph: pass cred pointer to ceph_mds_auth_match()

In the Linux kernel, the following vulnerability has been resolved: ceph: pass cred pointer to cephmdsauthmatch This eliminates a redundant getcurrentcred call, because cephmdscheckaccess has already obtained this pointer. As a side effect, this also fixes a reference leak in cephmdsauthmatch: by...