Pull nfsd fixes from Chuck Lever:

 - Two minor bug fixes

* tag 'nfsd-6.4-2' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux:
  nfsd: fix double fget() bug in __write_ports_addfd()
  nfsd: make a copy of struct iattr before calling notify_change

The bug here is that you cannot rely on getting the same socket
from multiple calls to fget() because userspace can influence
that.  This is a kind of double fetch bug.

The fix is to delete the svc_alien_sock() function and instead do
the checking inside the svc_addsock() function.

Fixes: 3064639423c4 ("nfsd: check passed socket's net matches NFSd superblock's one")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: NeilBrown <neilb@suse.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Pull NFS client fixes from Anna Schumaker:
 "Stable Fix:

   - Don't change task->tk_status after the call to rpc_exit_task

  Other Bugfixes:

   - Convert kmap_atomic() to kmap_local_folio()

   - Fix a potential double free with READ_PLUS"

* tag 'nfs-for-6.4-2' of git://git.linux-nfs.org/projects/anna/linux-nfs:
  NFSv4.2: Fix a potential double free with READ_PLUS
  SUNRPC: Don't change task->tk_status after the call to rpc_exit_task
  NFS: Convert kmap_atomic() to kmap_local_folio()

Some calls to rpc_exit_task() may deliberately change the value of
task->tk_status, for instance because it gets checked by the RPC call's
rpc_release() callback. That makes it wrong to reset the value to
task->tk_rpc_status.
In particular this causes a bug where the rpc_call_done() callback tries
to fail over a set of pNFS/flexfiles writes to a different IP address,
but the reset of task->tk_status causes nfs_commit_release_pages() to
immediately mark the file as having a fatal error.

Fixes: 39494194f93b ("SUNRPC: Fix races with rpc_killall_tasks()")
Cc: stable@vger.kernel.org # 6.1.x
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Pull nfsd fixes from Chuck Lever:

 - A collection of minor bug fixes

* tag 'nfsd-6.4-1' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux:
  NFSD: Remove open coding of string copy
  SUNRPC: Fix trace_svc_register() call site
  SUNRPC: always free ctxt when freeing deferred request
  SUNRPC: double free xprt_ctxt while still in use
  SUNRPC: Fix error handling in svc_setup_socket()
  SUNRPC: Fix encoding of accepted but unsuccessful RPC replies
  lockd: define nlm_port_min,max with CONFIG_SYSCTL
  nfsd: define exports_proc_ops with CONFIG_PROC_FS
  SUNRPC: Avoid relying on crypto API to derive CBC-CTS output IV

The trace event recorded incorrect values for the registered family,
protocol, and port because the arguments are in the wrong order.

Fixes: b4af59328c25 ("SUNRPC: Trace server-side rpcbind registration events")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Since the ->xprt_ctxt pointer was added to svc_deferred_req, it has not
been sufficient to use kfree() to free a deferred request.  We may need
to free the ctxt as well.

As freeing the ctxt is all that ->xpo_release_rqst() does, we repurpose
it to explicit do that even when the ctxt is not stored in an rqst.
So we now have ->xpo_release_ctxt() which is given an xprt and a ctxt,
which may have been taken either from an rqst or from a dreq.  The
caller is now responsible for clearing that pointer after the call to
->xpo_release_ctxt.

We also clear dr->xprt_ctxt when the ctxt is moved into a new rqst when
revisiting a deferred request.  This ensures there is only one pointer
to the ctxt, so the risk of double freeing in future is reduced.  The
new code in svc_xprt_release which releases both the ctxt and any
rq_deferred depends on this.

Fixes: 773f91b2cf3f ("SUNRPC: Fix NFSD's request deferral on RDMA transports")
Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

When an RPC request is deferred, the rq_xprt_ctxt pointer is moved out
of the svc_rqst into the svc_deferred_req.
When the deferred request is revisited, the pointer is copied into
the new svc_rqst - and also remains in the svc_deferred_req.

In the (rare?) case that the request is deferred a second time, the old
svc_deferred_req is reused - it still has all the correct content.
However in that case the rq_xprt_ctxt pointer is NOT cleared so that
when xpo_release_xprt is called, the ctxt is freed (UDP) or possible
added to a free list (RDMA).
When the deferred request is revisited for a second time, it will
reference this ctxt which may be invalid, and the free the object a
second time which is likely to oops.

So change svc_defer() to *always* clear rq_xprt_ctxt, and assert that
the value is now stored in the svc_deferred_req.

Fixes: 773f91b2cf3f ("SUNRPC: Fix NFSD's request deferral on RDMA transports")
Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Dan points out that sock_alloc_file() releases @sock on error, but
so do all of svc_setup_socket's callers, resulting in a double-
release if sock_alloc_file() returns an error.

Rather than allocating a struct file for all new sockets, allocate
one only for sockets created during a TCP accept. For the moment,
those are the only ones that will ever be used with RPC-with-TLS.

Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Fixes: ae0d77708aae ("SUNRPC: Ensure server-side sockets have a sock->file")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Jiri Slaby says:
> I bisected to this ... as it breaks nfs3-only servers in 6.3.
> I.e. /etc/nfs.conf containing:
> [nfsd]
> vers4=no
>
> The client sees:
>  mount("10.0.2.15:/tmp", "/mnt", "nfs", 0, "vers=4.2,addr=10.0.2.15,clientad"...) = -1 EIO (Input/output error)
>  write(2, "mount.nfs: mount system call fai"..., 45
>  mount.nfs: mount system call failed for /mnt
>
> And the kernel says:
>  nfs4_discover_server_trunking unhandled error -5. Exiting with error EIO

Reported-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://bugzilla.suse.com/show_bug.cgi?id=1210995
Fixes: 4bcf0343e8a6 ("SUNRPC: Set rq_accept_statp inside ->accept methods")
Tested-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>