linux-stable.git/include/linux/namei.h, branch v6.3.7

Merge tag 'nfsd-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux

2023-02-22T22:21:40+00:00

Pull nfsd updates from Chuck Lever:
 "Two significant security enhancements are part of this release:

   - NFSD's RPC header encoding and decoding, including RPCSEC GSS and
     gssproxy header parsing, has been overhauled to make it more
     memory-safe.

   - Support for Kerberos AES-SHA2-based encryption types has been added
     for both the NFS client and server. This provides a clean path for
     deprecating and removing insecure encryption types based on DES and
     SHA-1. AES-SHA2 is also FIPS-140 compliant, so that NFS with
     Kerberos may now be used on systems with fips enabled.

  In addition to these, NFSD is now able to handle crossing into an
  auto-mounted mount point on an exported NFS mount. A number of fixes
  have been made to NFSD's server-side copy implementation.

  RPC metrics have been converted to per-CPU variables. This helps
  reduce unnecessary cross-CPU and cross-node memory bus traffic, and
  significantly reduces noise when KCSAN is enabled"

* tag 'nfsd-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux: (121 commits)
  NFSD: Clean up nfsd_symlink()
  NFSD: copy the whole verifier in nfsd_copy_write_verifier
  nfsd: don't fsync nfsd_files on last close
  SUNRPC: Fix occasional warning when destroying gss_krb5_enctypes
  nfsd: fix courtesy client with deny mode handling in nfs4_upgrade_open
  NFSD: fix problems with cleanup on errors in nfsd4_copy
  nfsd: fix race to check ls_layouts
  nfsd: don't hand out delegation on setuid files being opened for write
  SUNRPC: Remove ->xpo_secure_port()
  SUNRPC: Clean up the svc_xprt_flags() macro
  nfsd: remove fs/nfsd/fault_inject.c
  NFSD: fix leaked reference count of nfsd4_ssc_umount_item
  nfsd: clean up potential nfsd_file refcount leaks in COPY codepath
  nfsd: zero out pointers after putting nfsd_files on COPY setup error
  SUNRPC: Fix whitespace damage in svcauth_unix.c
  nfsd: eliminate __nfs4_get_fd
  nfsd: add some kerneldoc comments for stateid preprocessing functions
  nfsd: eliminate find_deleg_file_locked
  nfsd: don't take nfsd4_copy ref for OP_OFFLOAD_STATUS
  SUNRPC: Add encryption self-tests
  ...

fs: namei: Allow follow_down() to uncover auto mounts

2023-02-20T14:20:08+00:00

This function is only used by NFSD to cross mount points.
If a mount point is of type auto mount, follow_down() will
not uncover it. Add LOOKUP_AUTOMOUNT to the lookup flags
to have ->d_automount() called when NFSD walks down the
mount tree.

Signed-off-by: Richard Weinberger 
Reviewed-by: Ian Kent 
Reviewed-by: Jeff Layton 
Acked-by: Al Viro 
Signed-off-by: Chuck Lever

fs: port ->permission() to pass mnt_idmap

2023-01-19T08:24:28+00:00

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Christian Brauner (Microsoft)

nd_jump_link(): constify path

2022-09-01T21:39:49+00:00

Reviewed-by: Christian Brauner (Microsoft) 
Signed-off-by: Al Viro

fs: add two trivial lookup helpers

2022-04-28T14:31:10+00:00

Similar to the addition of lookup_one() add a version of
lookup_one_unlocked() and lookup_one_positive_unlocked() that take
idmapped mounts into account. This is required to port overlay to
support idmapped base layers.

Cc: 
Tested-by: Giuseppe Scrivano 
Reviewed-by: Amir Goldstein 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Christian Brauner (Microsoft) 
Signed-off-by: Miklos Szeredi

namei: add mapping aware lookup helper

2021-08-23T11:19:12+00:00

Various filesystems rely on the lookup_one_len() helper to lookup a
single path component relative to a well-known starting point. Allow
such filesystems to support idmapped mounts by adding a version of this
helper to take the idmap into account when calling inode_permission().
This change is a required to let btrfs (and other filesystems) support
idmapped mounts.

Cc: Christoph Hellwig 
Cc: Al Viro 
Cc: Matthew Wilcox (Oracle) 
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Josef Bacik 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Christian Brauner 
Signed-off-by: David Sterba

take LOOKUP_{ROOT,ROOT_GRABBED,JUMPED} out of LOOKUP_... space

2021-04-07T17:57:13+00:00

Separate field in nameidata (nd->state) holding the flags that
should be internal-only - that way we both get some spare bits
in LOOKUP_... and get simpler rules for nd->root lifetime rules,
since we can set the replacement of LOOKUP_ROOT (ND_ROOT_PRESET)
at the same time we set nd->root.

Signed-off-by: Al Viro

fs: add support for LOOKUP_CACHED

2021-01-04T16:42:21+00:00

io_uring always punts opens to async context, since there's no control
over whether the lookup blocks or not. Add LOOKUP_CACHED to support
just doing the fast RCU based lookups, which we know will not block. If
we can do a cached path resolution of the filename, then we don't have
to always punt lookups for a worker.

During path resolution, we always do LOOKUP_RCU first. If that fails and
we terminate LOOKUP_RCU, then fail a LOOKUP_CACHED attempt as well.

Cc: Al Viro 
Signed-off-by: Jens Axboe 
Signed-off-by: Al Viro

sanitize handling of nd->last_type, kill LAST_BIND

2020-03-14T01:08:19+00:00

->last_type values are set in 3 places: path_init() (sets to LAST_ROOT),
link_path_walk (LAST_NORM/DOT/DOTDOT) and pick_link (LAST_BIND).

The are checked in walk_component(), lookup_last() and do_last().
They also get copied to the caller by filename_parentat().  In the last
3 cases the value is what we had at the return from link_path_walk().
In case of walk_component() it's either directly downstream from
assignment in link_path_walk() or, when called by lookup_last(), the
value we have at the return from link_path_walk().

The value at the entry into link_path_walk() can survive to return only
if the pathname contains nothing but slashes.  Note that pick_link()
never returns such - pure jumps are handled directly.  So for the calls
of link_path_walk() for trailing symlinks it does not matter what value
had been there at the entry; the value at the return won't depend upon it.

There are 3 call chains that might have pick_link() storing LAST_BIND:

1) pick_link() from step_into() from walk_component() from
link_path_walk().  In that case we will either be parsing the next
component immediately after return into link_path_walk(), which will
overwrite the ->last_type before anyone has a chance to look at it,
or we'll fail, in which case nobody will be looking at ->last_type at all.

2) pick_link() from step_into() from walk_component() from lookup_last().
The value is never looked at due to the above; it won't affect the value
seen at return from any link_path_walk().

3) pick_link() from step_into() from do_last().  Ditto.

In other words, assignemnt in pick_link() is pointless, and so is
LAST_BIND itself; nothing ever looks at that value.  Kill it off.
And make link_path_walk() _always_ assign ->last_type - in the only
case when the value at the entry might survive to the return that value
is always LAST_ROOT, inherited from path_init().  Move that assignment
from path_init() into the beginning of link_path_walk(), to consolidate
the things.

Historical note: LAST_BIND used to be used for the kludge with trailing
pure jump symlinks (extra iteration through the top-level loop).
No point keeping it anymore...

Signed-off-by: Al Viro

LOOKUP_MOUNTPOINT: fold path_mountpointat() into path_lookupat()

2020-03-14T01:08:17+00:00

New LOOKUP flag, telling path_lookupat() to act as path_mountpointat().
IOW, traverse mounts at the final point and skip revalidation of the
location where it ends up.

Signed-off-by: Al Viro