xs_sock_recv_cmsg was failing to call xs_sock_process_cmsg for any cmsg
type other than TLS_RECORD_TYPE_ALERT (TLS_RECORD_TYPE_DATA, and other
values not handled.) Based on my reading of the previous commit
(cc5d5908: sunrpc: fix client side handling of tls alerts), it looks
like only iov_iter_revert should be conditional on TLS_RECORD_TYPE_ALERT
(but that other cmsg types should still call xs_sock_process_cmsg). On
my machine, I was unable to connect (over mtls) to an NFS share hosted
on FreeBSD. With this patch applied, I am able to mount the share again.

Fixes: cc5d59081fa2 ("sunrpc: fix client side handling of tls alerts")
Signed-off-by: Justin Worrell <jworrell@gmail.com>
Reviewed-and-tested-by: Scott Mayhew <smayhew@redhat.com>
Link: https://lore.kernel.org/r/20250904211038.12874-3-jworrell@gmail.com
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

This reverts commit 14e41b16e8cb677bb440dca2edba8b041646c742.

This patch breaks the LTP acct02 test, so let's revert and look for a
better solution.

Reported-by: Mark Brown <broonie@kernel.org>
Reported-by: Harshvardhan Jha <harshvardhan.j.jha@oracle.com>
Link: https://lore.kernel.org/linux-nfs/7d4d57b0-39a3-49f1-8ada-60364743e3b4@sirena.org.uk/
Cc: stable@vger.kernel.org # 6.15.x
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Pull nfsd fixes from Chuck Lever:

 - A correctness fix for delegated timestamps

 - Address an NFSD shutdown hang when LOCALIO is in use

 - Prevent a remotely exploitable crasher when TLS is in use

* tag 'nfsd-6.17-1' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux:
  sunrpc: fix handling of server side tls alerts
  nfsd: avoid ref leak in nfsd_open_local_fh()
  nfsd: don't set the ctime on delegated atime updates

Pull NFS client updates from Trond Myklebust:
 "Highlights include:

  Stable fixes:
   - don't inherit NFS filesystem capabilities when crossing from one
     filesystem to another

  Bugfixes:
   - NFS wakeup of __nfs_lookup_revalidate() needs memory barriers
   - NFS improve bounds checking in nfs_fh_to_dentry()
   - NFS Fix allocation errors when writing to a NFS file backed
     loopback device
   - NFSv4: More listxattr fixes
   - SUNRPC: fix client handling of TLS alerts
   - pNFS block/scsi layout fix for an uninitialised pointer
     dereference
   - pNFS block/scsi layout fixes for the extent encoding, stripe
     mapping, and disk offset overflows
   - pNFS layoutcommit work around for RPC size limitations
   - pNFS/flexfiles avoid looping when handling fatal errors after
     layoutget
   - localio: fix various race conditions

  Features and cleanups:
   - Add NFSv4 support for retrieving the btime
   - NFS: Allow folio migration for the case of mode == MIGRATE_SYNC
   - NFS: Support using a kernel keyring to store TLS certificates
   - NFSv4: Speed up delegation lookup using a hash table
   - Assorted cleanups to remove unused variables and struct fields
   - Assorted new tracepoints to improve debugging"

* tag 'nfs-for-6.17-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (44 commits)
  NFS/localio: nfs_uuid_put() fix the wake up after unlinking the file
  NFS/localio: nfs_uuid_put() fix races with nfs_open/close_local_fh()
  NFS/localio: nfs_close_local_fh() fix check for file closed
  NFSv4: Remove duplicate lookups, capability probes and fsinfo calls
  NFS: Fix the setting of capabilities when automounting a new filesystem
  sunrpc: fix client side handling of tls alerts
  nfs/localio: use read_seqbegin() rather than read_seqbegin_or_lock()
  NFS: Fixup allocation flags for nfsiod's __GFP_NORETRY
  NFSv4.2: another fix for listxattr
  NFS: Fix filehandle bounds checking in nfs_fh_to_dentry()
  SUNRPC: Silence warnings about parameters not being described
  NFS: Clean up pnfs_put_layout_hdr()/pnfs_destroy_layout_final()
  NFS: Fix wakeup of __nfs_lookup_revalidate() in unblock_revalidate()
  NFS: use a hash table for delegation lookup
  NFS: track active delegations per-server
  NFS: move the delegation_watermark module parameter
  NFS: cleanup nfs_inode_reclaim_delegation
  NFS: cleanup error handling in nfs4_server_common_setup
  pNFS/flexfiles: don't attempt pnfs on fatal DS errors
  NFS: drop __exit from nfs_exit_keyring
  ...

Scott Mayhew discovered a security exploit in NFS over TLS in
tls_alert_recv() due to its assumption it can read data from
the msg iterator's kvec..

kTLS implementation splits TLS non-data record payload between
the control message buffer (which includes the type such as TLS
aler or TLS cipher change) and the rest of the payload (say TLS
alert's level/description) which goes into the msg payload buffer.

This patch proposes to rework how control messages are setup and
used by sock_recvmsg().

If no control message structure is setup, kTLS layer will read and
process TLS data record types. As soon as it encounters a TLS control
message, it would return an error. At that point, NFS can setup a
kvec backed msg buffer and read in the control message such as a
TLS alert. Msg iterator can advance the kvec pointer as a part of
the copy process thus we need to revert the iterator before calling
into the tls_alert_recv.

Reported-by: Scott Mayhew <smayhew@redhat.com>
Fixes: 5e052dda121e ("SUNRPC: Recognize control messages in server-side TCP socket code")
Suggested-by: Trond Myklebust <trondmy@hammerspace.com>
Cc: stable@vger.kernel.org
Signed-off-by: Olga Kornievskaia <okorniev@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

A security exploit was discovered in NFS over TLS in tls_alert_recv
due to its assumption that there is valid data in the msghdr's
iterator's kvec.

Instead, this patch proposes the rework how control messages are
setup and used by sock_recvmsg().

If no control message structure is setup, kTLS layer will read and
process TLS data record types. As soon as it encounters a TLS control
message, it would return an error. At that point, NFS can setup a kvec
backed control buffer and read in the control message such as a TLS
alert. Scott found that a msg iterator can advance the kvec pointer
as a part of the copy process thus we need to revert the iterator
before calling into the tls_alert_recv.

Fixes: dea034b963c8 ("SUNRPC: Capture CMSG metadata on client-side receive")
Suggested-by: Trond Myklebust <trondmy@hammerspace.com>
Suggested-by: Scott Mayhew <smayhew@redhat.com>
Signed-off-by: Olga Kornievskaia <okorniev@redhat.com>
Link: https://lore.kernel.org/r/20250731180058.4669-3-okorniev@redhat.com
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Pull rpc_pipefs updates from Al Viro:
 "Massage rpc_pipefs to use saner primitives and clean up the APIs
  provided to the rest of the kernel"

* tag 'pull-rpc_pipefs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  rpc_create_client_dir(): return 0 or -E...
  rpc_create_client_dir(): don't bother with rpc_populate()
  rpc_new_dir(): the last argument is always NULL
  rpc_pipe: expand the calls of rpc_mkdir_populate()
  rpc_gssd_dummy_populate(): don't bother with rpc_populate()
  rpc_mkpipe_dentry(): switch to simple_start_creating()
  rpc_pipe: saner primitive for creating regular files
  rpc_pipe: saner primitive for creating subdirectories
  rpc_pipe: don't overdo directory locking
  rpc_mkpipe_dentry(): saner calling conventions
  rpc_unlink(): saner calling conventions
  rpc_populate(): lift cleanup into callers
  rpc_unlink(): use simple_recursive_removal()
  rpc_{rmdir_,}depopulate(): use simple_recursive_removal() instead
  rpc_pipe: clean failure exits in fill_super
  new helper: simple_start_creating()

Pull dentry d_flags updates from Al Viro:
 "The current exclusion rules for dentry->d_flags stores are rather
  unpleasant. The basic rules are simple:

   - stores to dentry->d_flags are OK under dentry->d_lock

   - stores to dentry->d_flags are OK in the dentry constructor, before
     becomes potentially visible to other threads

  Unfortunately, there's a couple of exceptions to that, and that's
  where the headache comes from.

  The main PITA comes from d_set_d_op(); that primitive sets ->d_op of
  dentry and adjusts the flags that correspond to presence of individual
  methods. It's very easy to misuse; existing uses _are_ safe, but proof
  of correctness is brittle.

  Use in __d_alloc() is safe (we are within a constructor), but we might
  as well precalculate the initial value of 'd_flags' when we set the
  default ->d_op for given superblock and set 'd_flags' directly instead
  of messing with that helper.

  The reasons why other uses are safe are bloody convoluted; I'm not
  going to reproduce it here. See [1] for gory details, if you care. The
  critical part is using d_set_d_op() only just prior to
  d_splice_alias(), which makes a combination of d_splice_alias() with
  setting ->d_op, etc a natural replacement primitive.

  Better yet, if we go that way, it's easy to take setting ->d_op and
  modifying 'd_flags' under ->d_lock, which eliminates the headache as
  far as 'd_flags' exclusion rules are concerned. Other exceptions are
  minor and easy to deal with.

  What this series does:

   - d_set_d_op() is no longer available; instead a new primitive
     (d_splice_alias_ops()) is provided, equivalent to combination of
     d_set_d_op() and d_splice_alias().

   - new field of struct super_block - 's_d_flags'. This sets the
     default value of 'd_flags' to be used when allocating dentries on
     this filesystem.

   - new primitive for setting 's_d_op': set_default_d_op(). This
     replaces stores to 's_d_op' at mount time.

     All in-tree filesystems converted; out-of-tree ones will get caught
     by the compiler ('s_d_op' is renamed, so stores to it will be
     caught). 's_d_flags' is set by the same primitive to match the
     's_d_op'.

   - a lot of filesystems had sb->s_d_op->d_delete equal to
     always_delete_dentry; that is equivalent to setting
     DCACHE_DONTCACHE in 'd_flags', so such filesystems can bloody well
     set that bit in 's_d_flags' and drop 'd_delete()' from
     dentry_operations.

     In quite a few cases that results in empty dentry_operations, which
     means that we can get rid of those.

   - kill simple_dentry_operations - not needed anymore

   - massage d_alloc_parallel() to get rid of the other exception wrt
     'd_flags' stores - we can set DCACHE_PAR_LOOKUP as soon as we
     allocate the new dentry; no need to delay that until we commit to
     using the sucker.

  As the result, 'd_flags' stores are all either under ->d_lock or done
  before the dentry becomes visible in any shared data structures"

Link: https://lore.kernel.org/all/20250224010624.GT1977892@ZenIV/ [1]

* tag 'pull-dcache' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (21 commits)
  configfs: use DCACHE_DONTCACHE
  debugfs: use DCACHE_DONTCACHE
  efivarfs: use DCACHE_DONTCACHE instead of always_delete_dentry()
  9p: don't bother with always_delete_dentry
  ramfs, hugetlbfs, mqueue: set DCACHE_DONTCACHE
  kill simple_dentry_operations
  devpts, sunrpc, hostfs: don't bother with ->d_op
  shmem: no dentry retention past the refcount reaching zero
  d_alloc_parallel(): set DCACHE_PAR_LOOKUP earlier
  make d_set_d_op() static
  simple_lookup(): just set DCACHE_DONTCACHE
  tracefs: Add d_delete to remove negative dentries
  set_default_d_op(): calculate the matching value for ->d_flags
  correct the set of flags forbidden at d_set_d_op() time
  split d_flags calculation out of d_set_d_op()
  new helper: set_default_d_op()
  fuse: no need for special dentry_operations for root dentry
  switch procfs from d_set_d_op() to d_splice_alias_ops()
  new helper: d_splice_alias_ops()
  procfs: kill ->proc_dops
  ...

Warning: net/sunrpc/auth_gss/gss_krb5_crypto.c:902 function parameter
'len' not described in 'krb5_etm_decrypt'
Warning: net/sunrpc/auth_gss/gss_krb5_crypto.c:902 function parameter
'buf' not described in 'krb5_etm_decrypt'

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Remove a bunch of unused xdr_*decode* functions:
  The last use of xdr_decode_netobj() was removed in 2021 by:
commit 7cf96b6d0104 ("lockd: Update the NLMv4 SHARE arguments decoder to
use struct xdr_stream")
  The last use of xdr_decode_string_inplace() was removed in 2021 by:
commit 3049e974a7c7 ("lockd: Update the NLMv4 FREE_ALL arguments decoder
to use struct xdr_stream")
  The last use of xdr_stream_decode_opaque() was removed in 2024 by:
commit fed8a17c61ff ("xdrgen: typedefs should use the built-in string and
opaque functions")

  The functions xdr_stream_decode_string() and
xdr_stream_decode_opaque_dup() were both added in 2018 by the
commit 0e779aa70308 ("SUNRPC: Add helpers for decoding opaque and string
types")
but never used.

Remove them.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Link: https://lore.kernel.org/r/20250712233006.403226-1-linux@treblig.org
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>