linux-stable.git/fs/notify, branch v4.9.321

inotify: show inotify mask flags in proc fdinfo

2022-06-14T14:52:31+00:00

[ Upstream commit a32e697cda27679a0327ae2cafdad8c7170f548f ]

The inotify mask flags IN_ONESHOT and IN_EXCL_UNLINK are not "internal
to kernel" and should be exposed in procfs fdinfo so CRIU can restore
them.

Fixes: 6933599697c9 ("inotify: hide internal kernel bits from fdinfo")
Link: https://lore.kernel.org/r/20220422120327.3459282-2-amir73il@gmail.com
Signed-off-by: Amir Goldstein 
Signed-off-by: Jan Kara 
Signed-off-by: Sasha Levin

fanotify: fix handling of events on child sub-directory

2019-02-06T16:33:30+00:00

commit b469e7e47c8a075cc08bcd1e85d4365134bdcdd5 upstream.

When an event is reported on a sub-directory and the parent inode has
a mark mask with FS_EVENT_ON_CHILD|FS_ISDIR, the event will be sent to
fsnotify() even if the event type is not in the parent mark mask
(e.g. FS_OPEN).

Further more, if that event happened on a mount or a filesystem with
a mount/sb mark that does have that event type in their mask, the "on
child" event will be reported on the mount/sb mark.  That is not
desired, because user will get a duplicate event for the same action.

Note that the event reported on the victim inode is never merged with
the event reported on the parent inode, because of the check in
should_merge(): old_fsn->inode == new_fsn->inode.

Fix this by looking for a match of an actual event type (i.e. not just
FS_ISDIR) in parent's inode mark mask and by not reporting an "on child"
event to group if event type is only found on mount/sb marks.

[backport hint: The bug seems to have always been in fanotify, but this
                patch will only apply cleanly to v4.19.y]

Cc:  # v4.19
Signed-off-by: Amir Goldstein 
Signed-off-by: Jan Kara 
[amir: backport to v4.9]
Signed-off-by: Amir Goldstein 
Signed-off-by: Greg Kroah-Hartman

fanotify: fix logic of events on child

2018-04-24T07:34:18+00:00

commit 54a307ba8d3cd00a3902337ffaae28f436eeb1a4 upstream.

When event on child inodes are sent to the parent inode mark and
parent inode mark was not marked with FAN_EVENT_ON_CHILD, the event
will not be delivered to the listener process. However, if the same
process also has a mount mark, the event to the parent inode will be
delivered regadless of the mount mark mask.

This behavior is incorrect in the case where the mount mark mask does
not contain the specific event type. For example, the process adds
a mark on a directory with mask FAN_MODIFY (without FAN_EVENT_ON_CHILD)
and a mount mark with mask FAN_CLOSE_NOWRITE (without FAN_ONDIR).

A modify event on a file inside that directory (and inside that mount)
should not create a FAN_MODIFY event, because neither of the marks
requested to get that event on the file.

Fixes: 1968f5eed54c ("fanotify: use both marks when possible")
Cc: stable 
Signed-off-by: Amir Goldstein 
Signed-off-by: Jan Kara 
[natechancellor: Fix small conflict due to lack of 3cd5eca8d7a2f]
Signed-off-by: Nathan Chancellor 
Signed-off-by: Greg Kroah-Hartman

dentry name snapshots

2017-08-07T01:59:43+00:00

commit 49d31c2f389acfe83417083e1208422b4091cd9e upstream.

take_dentry_name_snapshot() takes a safe snapshot of dentry name;
if the name is a short one, it gets copied into caller-supplied
structure, otherwise an extra reference to external name is grabbed
(those are never modified).  In either case the pointer to stable
string is stored into the same structure.

dentry must be held by the caller of take_dentry_name_snapshot(),
but may be freely dropped afterwards - the snapshot will stay
until destroyed by release_dentry_name_snapshot().

Intended use:
	struct name_snapshot s;

	take_dentry_name_snapshot(&s, dentry);
	...
	access s.name
	...
	release_dentry_name_snapshot(&s);

Replaces fsnotify_oldname_...(), gets used in fsnotify to obtain the name
to pass down with event.

Signed-off-by: Al Viro 
Signed-off-by: Greg Kroah-Hartman

fanotify: don't expose EOPENSTALE to userspace

2017-05-25T13:44:31+00:00

commit 4ff33aafd32e084f5ee7faa54ba06e95f8b1b8af upstream.

When delivering an event to userspace for a file on an NFS share,
if the file is deleted on server side before user reads the event,
user will not get the event.

If the event queue contained several events, the stale event is
quietly dropped and read() returns to user with events read so far
in the buffer.

If the event queue contains a single stale event or if the stale
event is a permission event, read() returns to user with the kernel
internal error code 518 (EOPENSTALE), which is not a POSIX error code.

Check the internal return value -EOPENSTALE in fanotify_read(), just
the same as it is checked in path_openat() and drop the event in the
cases that it is not already dropped.

This is a reproducer from Marko Rauhamaa:

Just take the example program listed under "man fanotify" ("fantest")
and follow these steps:

    ==============================================================
    NFS Server    NFS Client(1)     NFS Client(2)
    ==============================================================
    # echo foo >/nfsshare/bar.txt
                  # cat /nfsshare/bar.txt
                  foo
                                    # ./fantest /nfsshare
                                    Press enter key to terminate.
                                    Listening for events.
    # rm -f /nfsshare/bar.txt
                  # cat /nfsshare/bar.txt
                                    read: Unknown error 518
                  cat: /nfsshare/bar.txt: Operation not permitted
    ==============================================================

where NFS Client (1) and (2) are two terminal sessions on a single NFS
Client machine.

Reported-by: Marko Rauhamaa 
Tested-by: Marko Rauhamaa 
Cc: 
Signed-off-by: Amir Goldstein 
Signed-off-by: Jan Kara 
Signed-off-by: Greg Kroah-Hartman

fsnotify: Fix possible use-after-free in inode iteration on umount

2017-01-09T07:32:22+00:00

commit 5716863e0f8251d3360d4cbfc0e44e08007075df upstream.

fsnotify_unmount_inodes() plays complex tricks to pin next inode in the
sb->s_inodes list when iterating over all inodes. Furthermore the code has a
bug that if the current inode is the last on i_sb_list that does not have e.g.
I_FREEING set, then we leave next_i pointing to inode which may get removed
from the i_sb_list once we drop s_inode_list_lock thus resulting in
use-after-free issues (usually manifesting as infinite looping in
fsnotify_unmount_inodes()).

Fix the problem by keeping current inode pinned somewhat longer. Then we can
make the code much simpler and standard.

Signed-off-by: Jan Kara 
Signed-off-by: Greg Kroah-Hartman

fsnotify: clean up spinlock assertions

2016-10-08T01:46:26+00:00

Use assert_spin_locked() macro instead of hand-made BUG_ON statements.

Link: http://lkml.kernel.org/r/1474537439-18919-1-git-send-email-jack@suse.cz
Signed-off-by: Jan Kara 
Suggested-by: Heiner Kallweit 
Reviewed-by: Jeff Layton 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fanotify: fix possible false warning when freeing events

2016-10-08T01:46:26+00:00

When freeing permission events by fsnotify_destroy_event(), the warning
WARN_ON(!list_empty(&event->list)); may falsely hit.

This is because although fanotify_get_response() saw event->response
set, there is nothing to make sure the current CPU also sees the removal
of the event from the list.  Add proper locking around the WARN_ON() to
avoid the false warning.

Link: http://lkml.kernel.org/r/1473797711-14111-7-git-send-email-jack@suse.cz
Reported-by: Miklos Szeredi 
Signed-off-by: Jan Kara 
Reviewed-by: Lino Sanfilippo 
Cc: Eric Paris 
Cc: Al Viro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fanotify: use notification_lock instead of access_lock

2016-10-08T01:46:26+00:00

Fanotify code has its own lock (access_lock) to protect a list of events
waiting for a response from userspace.

However this is somewhat awkward as the same list_head in the event is
protected by notification_lock if it is part of the notification queue
and by access_lock if it is part of the fanotify private queue which
makes it difficult for any reliable checks in the generic code.  So make
fanotify use the same lock - notification_lock - for protecting its
private event list.

Link: http://lkml.kernel.org/r/1473797711-14111-6-git-send-email-jack@suse.cz
Signed-off-by: Jan Kara 
Reviewed-by: Lino Sanfilippo 
Cc: Miklos Szeredi 
Cc: Eric Paris 
Cc: Al Viro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fsnotify: convert notification_mutex to a spinlock

2016-10-08T01:46:26+00:00

notification_mutex is used to protect the list of pending events.  As such
there's no reason to use a sleeping lock for it.  Convert it to a
spinlock.

[jack@suse.cz: fixed version]
  Link: http://lkml.kernel.org/r/1474031567-1831-1-git-send-email-jack@suse.cz
Link: http://lkml.kernel.org/r/1473797711-14111-5-git-send-email-jack@suse.cz
Signed-off-by: Jan Kara 
Reviewed-by: Lino Sanfilippo 
Tested-by: Guenter Roeck 
Cc: Miklos Szeredi 
Cc: Eric Paris 
Cc: Al Viro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds