[ Upstream commit 867a448d587e7fa845bceaf4ee1c632448f2a9fa ]

Add flags argument to fsnotify_alloc_group(), define and use the flag
FSNOTIFY_GROUP_USER in inotify and fanotify instead of the helper
fsnotify_alloc_user_group() to indicate user allocation.

Although the flag FSNOTIFY_GROUP_USER is currently not used after group
allocation, we store the flags argument in the group struct for future
use of other group flags.

Link: https://lore.kernel.org/r/20220422120327.3459282-5-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

[ Upstream commit dabe729dddca550446e9cc118c96d1f91703345b ]

Clarify argument names and contract for fsnotify_create() and
fsnotify_mkdir() to reflect the anomaly of kernfs, which leaves dentries
negavite after mkdir/create.

Remove the WARN_ON(!inode) in audit code that were added by the Fixes
commit under the wrong assumption that dentries cannot be negative after
mkdir/create.

Fixes: aa93bdc5500c ("fsnotify: use helpers to access data by data_type")
Link: https://lore.kernel.org/linux-fsdevel/87mtp5yz0q.fsf@collabora.com/
Link: https://lore.kernel.org/r/20211025192746.66445-4-krisman@collabora.com
Reviewed-by: Jan Kara <jack@suse.cz>
Reported-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

commit 969d90ec212bae4b45bf9d21d7daa30aa6cf055e upstream.

eBPF can end up calling into the audit code from some odd places, and
some of these places don't have @current set properly so we end up
tripping the `WARN_ON_ONCE(!current->mm)` near the top of
`audit_exe_compare()`.  While the basic `!current->mm` check is good,
the `WARN_ON_ONCE()` results in some scary console messages so let's
drop that and just do the regular `!current->mm` check to avoid
problems.

Cc: <stable@vger.kernel.org>
Fixes: 47846d51348d ("audit: don't take task_lock() in audit_exe_compare() code path")
Reported-by: Artem Savkov <asavkov@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 47846d51348dd62e5231a83be040981b17c955fa upstream.

The get_task_exe_file() function locks the given task with task_lock()
which when used inside audit_exe_compare() can cause deadlocks on
systems that generate audit records when the task_lock() is held. We
resolve this problem with two changes: ignoring those cases where the
task being audited is not the current task, and changing our approach
to obtaining the executable file struct to not require task_lock().

With the intent of the audit exe filter being to filter on audit events
generated by processes started by the specified executable, it makes
sense that we would only want to use the exe filter on audit records
associated with the currently executing process, e.g. @current.  If
we are asked to filter records using a non-@current task_struct we can
safely ignore the exe filter without negatively impacting the admin's
expectations for the exe filter.

Knowing that we only have to worry about filtering the currently
executing task in audit_exe_compare() we can do away with the
task_lock() and call get_mm_exe_file() with @current->mm directly.

Cc: <stable@vger.kernel.org>
Fixes: 5efc244346f9 ("audit: fix exe_file access in audit_exe_compare")
Reported-by: Andreas Steinmetz <anstein99@googlemail.com>
Reviewed-by: John Johansen <john.johanse@canonical.com>
Reviewed-by: Mateusz Guzik <mjguzik@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The handle_inode_event() interface was added as (quoting comment):
"a simple variant of handle_event() for groups that only have inode
marks and don't have ignore mask".

In other words, all backends except fanotify.  The inotify backend
also falls under this category, but because it required extra arguments
it was left out of the initial pass of backends conversion to the
simple interface.

This results in code duplication between the generic helper
fsnotify_handle_event() and the inotify_handle_event() callback
which also happen to be buggy code.

Generalize the handle_inode_event() arguments and add the check for
FS_EXCL_UNLINK flag to the generic helper, so inotify backend could
be converted to use the simple interface.

Link: https://lore.kernel.org/r/20201202120713.702387-2-amir73il@gmail.com
CC: stable@vger.kernel.org
Fixes: b9a1b9772509 ("fsnotify: create method handle_inode_event() in fsnotify_operations")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>

The method handle_event() grew a lot of complexity due to the design of
fanotify and merging of ignore masks.

Most backends do not care about this complex functionality, so we can hide
this complexity from them.

Introduce a method handle_inode_event() that serves those backends and
passes a single inode mark and less arguments.

This change converts all backends except fanotify and inotify to use the
simplified handle_inode_event() method.  In pricipal, inotify could have
also used the new method, but that would require passing more arguments
on the simple helper (data, data_type, cookie), so we leave it with the
handle_event() method.

Link: https://lore.kernel.org/r/20200722125849.17418-9-amir73il@gmail.com
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>

The audit group marks mask does not contain any events possible on
a child so setting the flag FS_EVENT_ON_CHILD in the mask is counter
productive.

It may lead to the undesired outcome of setting the dentry flag
DCACHE_FSNOTIFY_PARENT_WATCHED on a directory inode even though it is
not watching children, because the audit mark contribute the flag
FS_EVENT_ON_CHILD to the inode's fsnotify_mask and another mark could
be contributing an event that is possible on child to the inode's mask.

Furthermore in the following patches we want to use FS_EVENT_ON_CHILD
for non-dir inodes for other purposes so stop using the flag.

Link: https://lore.kernel.org/r/20200722125849.17418-4-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>

The 'inode' argument to handle_event(), sometimes referred to as
'to_tell' is somewhat obsolete.
It is a remnant from the times when a group could only have an inode mark
associated with an event.

We now pass an iter_info array to the callback, with all marks associated
with an event.

Most backends ignore this argument, with two exceptions:
1. dnotify uses it for sanity check that event is on directory
2. fanotify uses it to report fid of directory on directory entry
   modification events

Remove the 'inode' argument and add a 'dir' argument.
The callback function signature is deliberately changed, because
the meaning of the argument has changed and the arguments have
been documented.

The 'dir' argument is set to when 'file_name' is specified and it is
referring to the directory that the 'file_name' entry belongs to.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>

Pull fsnotify updates from Jan Kara:
 "This implements the fanotify FAN_DIR_MODIFY event.

  This event reports the name in a directory under which a change
  happened and together with the directory filehandle and fstatat()
  allows reliable and efficient implementation of directory
  synchronization"

* tag 'fsnotify_for_v5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  fanotify: Fix the checks in fanotify_fsid_equal
  fanotify: report name info for FAN_DIR_MODIFY event
  fanotify: record name info for FAN_DIR_MODIFY event
  fanotify: Drop fanotify_event_has_fid()
  fanotify: prepare to report both parent and child fid's
  fanotify: send FAN_DIR_MODIFY event flavor with dir inode and name
  fanotify: divorce fanotify_path_event and fanotify_fid_event
  fanotify: Store fanotify handles differently
  fanotify: Simplify create_fd()
  fanotify: fix merging marks masks with FAN_ONDIR
  fanotify: merge duplicate events on parent and child
  fsnotify: replace inode pointer with an object id
  fsnotify: simplify arguments passing to fsnotify_parent()
  fsnotify: use helpers to access data by data_type
  fsnotify: funnel all dirent events through fsnotify_name()
  fsnotify: factor helpers fsnotify_dentry() and fsnotify_file()
  fsnotify: tidy up FS_ and FAN_ constants

Create helpers to access path and inode from different data types.

Link: https://lore.kernel.org/r/20200319151022.31456-5-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>