linux.git/fs/notify, branch v6.6

fanotify: limit reporting of event with non-decodeable file handles

2023-10-19T14:19:20+00:00

Commit a95aef69a740 ("fanotify: support reporting non-decodeable file
handles") merged in v6.5-rc1, added the ability to use an fanotify group
with FAN_REPORT_FID mode to watch filesystems that do not support nfs
export, but do know how to encode non-decodeable file handles, with the
newly introduced AT_HANDLE_FID flag.

At the time that this commit was merged, there were no filesystems
in-tree with those traits.

Commit 16aac5ad1fa9 ("ovl: support encoding non-decodable file handles"),
merged in v6.6-rc1, added this trait to overlayfs, thus allowing fanotify
watching of overlayfs with FAN_REPORT_FID mode.

In retrospect, allowing an fanotify filesystem/mount mark on such
filesystem in FAN_REPORT_FID mode will result in getting events with
file handles, without the ability to resolve the filesystem objects from
those file handles (i.e. no open_by_handle_at() support).

For v6.6, the safer option would be to allow this mode for inode marks
only, where the caller has the opportunity to use name_to_handle_at() at
the time of setting the mark. In the future we can revise this decision.

Fixes: a95aef69a740 ("fanotify: support reporting non-decodeable file handles")
Signed-off-by: Amir Goldstein 
Signed-off-by: Jan Kara 
Message-Id: <20231018100000.2453965-2-amir73il@gmail.com>

dnotify: Pass argument of fcntl_dirnotify as int

2023-07-10T12:36:12+00:00

The interface for fcntl expects the argument passed for the command
F_DIRNOTIFY to be of type int. The current code wrongly treats it as
a long. In order to avoid access to undefined bits, we should explicitly
cast the argument to int.

Cc: Jan Kara 
Cc: Amir Goldstein 
Cc: Alexander Viro 
Cc: Christian Brauner 
Cc: Jeff Layton 
Cc: Chuck Lever 
Cc: Kevin Brodsky 
Cc: Vincenzo Frascino 
Cc: Szabolcs Nagy 
Cc: "Theodore Ts'o" 
Cc: David Laight 
Cc: Mark Rutland 
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-morello@op-lists.linaro.org
Acked-by: Jan Kara 
Signed-off-by: Luca Vizzarro 
Message-Id: <20230414152459.816046-6-Luca.Vizzarro@arm.com>
Signed-off-by: Christian Brauner

fanotify: disallow mount/sb marks on kernel internal pseudo fs

2023-07-04T11:29:29+00:00

Hopefully, nobody is trying to abuse mount/sb marks for watching all
anonymous pipes/inodes.

I cannot think of a good reason to allow this - it looks like an
oversight that dated back to the original fanotify API.

Link: https://lore.kernel.org/linux-fsdevel/20230628101132.kvchg544mczxv2pm@quack3/
Fixes: 0ff21db9fcc3 ("fanotify: hooks the fanotify_mark syscall to the vfsmount code")
Signed-off-by: Amir Goldstein 
Reviewed-by: Christian Brauner 
Signed-off-by: Jan Kara 
Message-Id: <20230629042044.25723-1-amir73il@gmail.com>

exportfs: check for error return value from exportfs_encode_*()

2023-05-25T11:17:04+00:00

The exportfs_encode_*() helpers call the filesystem ->encode_fh()
method which returns a signed int.

All the in-tree implementations of ->encode_fh() return a positive
integer and FILEID_INVALID (255) for error.

Fortify the callers for possible future ->encode_fh() implementation
that will return a negative error value.

name_to_handle_at() would propagate the returned error to the users
if filesystem ->encode_fh() method returns an error.

Reported-by: Dan Carpenter 
Link: https://lore.kernel.org/linux-fsdevel/ca02955f-1877-4fde-b453-3c1d22794740@kili.mountain/
Signed-off-by: Amir Goldstein 
Reviewed-by: Jeff Layton 
Signed-off-by: Jan Kara 
Message-Id: <20230524154825.881414-1-amir73il@gmail.com>

fanotify: support reporting non-decodeable file handles

2023-05-25T11:17:04+00:00

fanotify users do not always need to decode the file handles reported
with FAN_REPORT_FID.

Relax the restriction that filesystem needs to support NFS export and
allow reporting file handles from filesystems that only support ecoding
unique file handles.

Even filesystems that do not have export_operations at all can fallback
to use the default FILEID_INO32_GEN encoding, but we use the existence
of export_operations as an indication that the encoded file handles will
be sufficiently unique and that user will be able to compare them to
filesystem objects using AT_HANDLE_FID flag to name_to_handle_at(2).

For filesystems that do not support NFS export, users will have to use
the AT_HANDLE_FID of name_to_handle_at(2) if they want to compare the
object in path to the object fid reported in an event.

Signed-off-by: Amir Goldstein 
Signed-off-by: Jan Kara 
Message-Id: <20230502124817.3070545-5-amir73il@gmail.com>

exportfs: add explicit flag to request non-decodeable file handles

2023-05-22T16:08:37+00:00

So far, all callers of exportfs_encode_inode_fh(), except for fsnotify's
show_mark_fhandle(), check that filesystem can decode file handles, but
we would like to add more callers that do not require a file handle that
can be decoded.

Introduce a flag to explicitly request a file handle that may not to be
decoded later and a wrapper exportfs_encode_fid() that sets this flag
and convert show_mark_fhandle() to use the new wrapper.

This will be used to allow adding fanotify support to filesystems that
do not support NFS export.

Acked-by: Jeff Layton 
Acked-by: Chuck Lever 
Signed-off-by: Amir Goldstein 
Signed-off-by: Jan Kara 
Message-Id: <20230502124817.3070545-3-amir73il@gmail.com>

inotify: Avoid reporting event with invalid wd

2023-04-25T10:36:55+00:00

When inotify_freeing_mark() races with inotify_handle_inode_event() it
can happen that inotify_handle_inode_event() sees that i_mark->wd got
already reset to -1 and reports this value to userspace which can
confuse the inotify listener. Avoid the problem by validating that wd is
sensible (and pretend the mark got removed before the event got
generated otherwise).

CC: stable@vger.kernel.org
Fixes: 7e790dd5fc93 ("inotify: fix error paths in inotify_update_watch")
Message-Id: <20230424163219.9250-1-jack@suse.cz>
Reported-by: syzbot+4a06d4373fd52f0b2f9c@syzkaller.appspotmail.com
Reviewed-by: Amir Goldstein 
Signed-off-by: Jan Kara

fanotify: use pidfd_prepare()

2023-04-03T09:16:57+00:00

We generally try to avoid installing a file descriptor into the caller's
file descriptor table just to close it again via close_fd() in case an
error occurs. Instead we reserve a file descriptor but don't install it
into the caller's file descriptor table yet. If we fail for other,
unrelated reasons we can just close the reserved file descriptor and if
we make it past all meaningful error paths we just install it. Fanotify
gets this right already for one fd type but not for pidfds.

Use the new pidfd_prepare() helper to reserve a pidfd and a pidfd file
and switch to the more common fd allocation and installation pattern.

Acked-by: Jan Kara 
Message-Id: <20230327-pidfd-file-api-v1-3-5c0e9a3158e4@kernel.org>
Signed-off-by: Christian Brauner

Merge tag 'rcu.2023.02.10a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu

2023-02-21T18:45:51+00:00

Pull RCU updates from Paul McKenney:

 - Documentation updates

 - Miscellaneous fixes, perhaps most notably:

      - Throttling callback invocation based on the number of callbacks
        that are now ready to invoke instead of on the total number of
        callbacks

      - Several patches that suppress false-positive boot-time
        diagnostics, for example, due to lockdep not yet being
        initialized

      - Make expedited RCU CPU stall warnings dump stacks of any tasks
        that are blocking the stalled grace period. (Normal RCU CPU
        stall warnings have done this for many years)

      - Lazy-callback fixes to avoid delays during boot, suspend, and
        resume. (Note that lazy callbacks must be explicitly enabled, so
        this should not (yet) affect production use cases)

 - Make kfree_rcu() and friends take advantage of polled grace periods,
   thus reducing memory footprint by almost two orders of magnitude,
   admittedly on a microbenchmark

   This also begins the transition from kfree_rcu(p) to
   kfree_rcu_mightsleep(p). This transition was motivated by bugs where
   kfree_rcu(p), which can block, was typed instead of the intended
   kfree_rcu(p, rh)

 - SRCU updates, perhaps most notably fixing a bug that causes SRCU to
   fail when booted on a system with a non-zero boot CPU. This
   surprising situation actually happens for kdump kernels on the
   powerpc architecture

   This also adds an srcu_down_read() and srcu_up_read(), which act like
   srcu_read_lock() and srcu_read_unlock(), but allow an SRCU read-side
   critical section to be handed off from one task to another

 - Clean up the now-useless SRCU Kconfig option

   There are a few more commits that are not yet acked or pulled into
   maintainer trees, and these will be in a pull request for a later
   merge window

 - RCU-tasks updates, perhaps most notably these fixes:

      - A strange interaction between PID-namespace unshare and the
        RCU-tasks grace period that results in a low-probability but
        very real hang

      - A race between an RCU tasks rude grace period on a single-CPU
        system and CPU-hotplug addition of the second CPU that can
        result in a too-short grace period

      - A race between shrinking RCU tasks down to a single callback
        list and queuing a new callback to some other CPU, but where
        that queuing is delayed for more than an RCU grace period. This
        can result in that callback being stranded on the non-boot CPU

 - Torture-test updates and fixes

 - Torture-test scripting updates and fixes

 - Provide additional RCU CPU stall-warning information in kernels built
   with CONFIG_RCU_CPU_STALL_CPUTIME=y, and restore the full five-minute
   timeout limit for expedited RCU CPU stall warnings

* tag 'rcu.2023.02.10a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu: (80 commits)
  rcu/kvfree: Add kvfree_rcu_mightsleep() and kfree_rcu_mightsleep()
  kernel/notifier: Remove CONFIG_SRCU
  init: Remove "select SRCU"
  fs/quota: Remove "select SRCU"
  fs/notify: Remove "select SRCU"
  fs/btrfs: Remove "select SRCU"
  fs: Remove CONFIG_SRCU
  drivers/pci/controller: Remove "select SRCU"
  drivers/net: Remove "select SRCU"
  drivers/md: Remove "select SRCU"
  drivers/hwtracing/stm: Remove "select SRCU"
  drivers/dax: Remove "select SRCU"
  drivers/base: Remove CONFIG_SRCU
  rcu: Disable laziness if lazy-tracking says so
  rcu: Track laziness during boot and suspend
  rcu: Remove redundant call to rcu_boost_kthread_setaffinity()
  rcu: Allow up to five minutes expedited RCU CPU stall-warning timeouts
  rcu: Align the output of RCU CPU stall warning messages
  rcu: Add RCU stall diagnosis information
  sched: Add helper nr_context_switches_cpu()
  ...

fanotify,audit: Allow audit to use the full permission event response

2023-02-07T11:53:53+00:00

This patch passes the full response so that the audit function can use all
of it. The audit function was updated to log the additional information in
the AUDIT_FANOTIFY record.

Currently the only type of fanotify info that is defined is an audit
rule number, but convert it to hex encoding to future-proof the field.
Hex encoding suggested by Paul Moore .

The {subj,obj}_trust values are {0,1,2}, corresponding to no, yes, unknown.

Sample records:
  type=FANOTIFY msg=audit(1600385147.372:590): resp=2 fan_type=1 fan_info=3137 subj_trust=3 obj_trust=5
  type=FANOTIFY msg=audit(1659730979.839:284): resp=1 fan_type=0 fan_info=0 subj_trust=2 obj_trust=2

Suggested-by: Steve Grubb 
Link: https://lore.kernel.org/r/3075502.aeNJFYEL58@x2
Tested-by: Steve Grubb 
Acked-by: Steve Grubb 
Signed-off-by: Richard Guy Briggs 
Signed-off-by: Jan Kara 
Message-Id: