linux-stable.git/fs/notify, branch v3.15.4

fanotify: fix -EOVERFLOW with large files on 64-bit

2014-05-06T20:04:59+00:00

On 64-bit systems, O_LARGEFILE is automatically added to flags inside
the open() syscall (also openat(), blkdev_open(), etc).  Userspace
therefore defines O_LARGEFILE to be 0 - you can use it, but it's a
no-op.  Everything should be O_LARGEFILE by default.

But: when fanotify does create_fd() it uses dentry_open(), which skips
all that.  And userspace can't set O_LARGEFILE in fanotify_init()
because it's defined to 0.  So if fanotify gets an event regarding a
large file, the read() will just fail with -EOVERFLOW.

This patch adds O_LARGEFILE to fanotify_init()'s event_f_flags on 64-bit
systems, using the same test as open()/openat()/etc.

Addresses https://bugzilla.redhat.com/show_bug.cgi?id=696821

Signed-off-by: Will Woods 
Acked-by: Eric Paris 
Reviewed-by: Jan Kara 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fanotify: move unrelated handling from copy_event_to_user()

2014-04-03T23:20:51+00:00

Move code moving event structure to access_list from copy_event_to_user()
to fanotify_read() where it is more logical (so that we can immediately
see in the main loop that we either move the event to a different list
or free it).  Also move special error handling for permission events
from copy_event_to_user() to the main loop to have it in one place with
error handling for normal events.  This makes copy_event_to_user()
really only copy the event to user without any side effects.

Signed-off-by: Jan Kara 
Cc: Eric Paris 
Cc: Al Viro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fanotify: reorganize loop in fanotify_read()

2014-04-03T23:20:51+00:00

Swap the error / "read ok" branches in the main loop of fanotify_read().
We will grow the "read ok" part in the next patch and this makes the
indentation easier.  Also it is more common to have error conditions
inside an 'if' instead of the fast path.

Signed-off-by: Jan Kara 
Cc: Eric Paris 
Cc: Al Viro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fanotify: convert access_mutex to spinlock

2014-04-03T23:20:51+00:00

access_mutex is used only to guard operations on access_list.  There's
no need for sleeping within this lock so just make a spinlock out of it.

Signed-off-by: Jan Kara 
Cc: Eric Paris 
Cc: Al Viro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fanotify: use fanotify event structure for permission response processing

2014-04-03T23:20:51+00:00

Currently, fanotify creates new structure to track the fact that
permission event has been reported to userspace and someone is waiting
for a response to it.  As event structures are now completely in the
hands of each notification framework, we can use the event structure for
this tracking instead of allocating a new structure.

Since this makes the event structures for normal events and permission
events even more different and the structures have different lifetime
rules, we split them into two separate structures (where permission
event structure contains the structure for a normal event).  This makes
normal events 8 bytes smaller and the code a tad bit cleaner.

[akpm@linux-foundation.org: fix build]
Signed-off-by: Jan Kara 
Cc: Eric Paris 
Cc: Al Viro 
Cc: Wu Fengguang 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fanotify: remove useless bypass_perm check

2014-04-03T23:20:51+00:00

The prepare_for_access_response() function checks whether
group->fanotify_data.bypass_perm is set.  However this test can never be
true because prepare_for_access_response() is called only from
fanotify_read() which means fanotify group is alive with an active fd
while bypass_perm is set from fanotify_release() when all file
descriptors pointing to the group are closed and the group is going
away.

Signed-off-by: Jan Kara 
Cc: Eric Paris 
Cc: Al Viro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fsnotify: Allocate overflow events with proper type

2014-02-25T10:18:06+00:00

Commit 7053aee26a35 "fsnotify: do not share events between notification
groups" used overflow event statically allocated in a group with the
size of the generic notification event. This causes problems because
some code looks at type specific parts of event structure and gets
confused by a random data it sees there and causes crashes.

Fix the problem by allocating overflow event with type corresponding to
the group type so code cannot get confused.

Signed-off-by: Jan Kara

fanotify: Handle overflow in case of permission events

2014-02-25T10:17:58+00:00

If the event queue overflows when we are handling permission event, we
will never get response from userspace. So we must avoid waiting for it.
Change fsnotify_add_notify_event() to return whether overflow has
happened so that we can detect it in fanotify_handle_event() and act
accordingly.

Signed-off-by: Jan Kara

fsnotify: Fix detection whether overflow event is queued

2014-02-25T10:17:52+00:00

Currently we didn't initialize event's list head when we removed it from
the event list. Thus a detection whether overflow event is already
queued wasn't working. Fix it by always initializing the list head when
deleting event from a list.

Signed-off-by: Jan Kara

inotify: Fix reporting of cookies for inotify events

2014-02-18T10:17:17+00:00

My rework of handling of notification events (namely commit 7053aee26a35
"fsnotify: do not share events between notification groups") broke
sending of cookies with inotify events. We didn't propagate the value
passed to fsnotify() properly and passed 4 uninitialized bytes to
userspace instead (so it is also an information leak). Sadly I didn't
notice this during my testing because inotify cookies aren't used very
much and LTP inotify tests ignore them.

Fix the problem by passing the cookie value properly.

Fixes: 7053aee26a3548ebaba046ae2e52396ccf56ac6c
Reported-by: Vegard Nossum 
Signed-off-by: Jan Kara