nfsd: decouple the xprtsec policy check from check_nfsd_access()
commit e4f574ca9c6dfa66695bb054ff5df43ecea873ec upstream.
A while back I had reported that an NFSv3 client could successfully
mount using '-o xprtsec=none' an export that had been exported with
'xprtsec=tls:mtls'. By "successfully" I mean that the mount command
would succeed and the mount would show up in /proc/mount. Attempting
to do anything futher with the mount would be met with NFS3ERR_ACCES.
This was fixed (albeit accidentally) by commit bb4f07f2409c ("nfsd:
Fix NFSD_MAY_BYPASS_GSS and NFSD_MAY_BYPASS_GSS_ON_ROOT") and was
subsequently re-broken by commit 0813c5f01249 ("nfsd: fix access
checking for NLM under XPRTSEC policies").
Transport Layer Security isn't an RPC security flavor or pseudo-flavor,
so we shouldn't be conflating them when determining whether the access
checks can be bypassed. Split check_nfsd_access() into two helpers, and
have __fh_verify() call the helpers directly since __fh_verify() has
logic that allows one or both of the checks to be skipped. All other
sites will continue to call check_nfsd_access().
Link: https://lore.kernel.org/linux-nfs/ZjO3Qwf_G87yNXb2@aion/
Fixes: 9280c5774314 ("NFSD: Handle new xprtsec= export option")
Cc: stable@vger.kernel.org
Signed-off-by: Scott Mayhew <smayhew@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
3 files changed
