Commit Graph

81 Commits

Author SHA1 Message Date
Al Viro 2903ff019b switch simple cases of fget_light to fdget
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-09-26 22:20:08 -04:00
Al Viro 352e3b2492 fanotify: sanitize failure exits in copy_event_to_user()
* do copy_to_user() before prepare_for_access_response(); that kills
the need in remove_access_response().
* don't do fd_install() until we are past the last possible failure
exit.  Don't use sys_close() on cleanup side - just put_unused_fd()
and fput().  Less racy that way...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-09-26 21:08:52 -04:00
Al Viro 765927b2d5 switch dentry_open() to struct path, make it grab references itself
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-23 00:01:29 +04:00
Al Viro c63181e6b6 vfs: move fsnotify junk to struct mount
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:12 -05:00
Lucas De Marchi 25985edced Fix common misspellings
Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
2011-03-31 11:26:23 -03:00
Justin P. Mattock ae0e47f02a Remove one to many n's in a word
Signed-off-by: Justin P. Mattock <justinmattock@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-03-01 15:47:58 +01:00
Jiri Kosina 4b7bd36470 Merge branch 'master' into for-next
Conflicts:
	MAINTAINERS
	arch/arm/mach-omap2/pm24xx.c
	drivers/scsi/bfa/bfa_fcpim.c

Needed to update to apply fixes for which the old branch was too
outdated.
2010-12-22 18:57:02 +01:00
Eric Paris 7d13162332 fanotify: fill in the metadata_len field on struct fanotify_event_metadata
The fanotify_event_metadata now has a field which is supposed to
indicate the length of the metadata portion of the event.  Fill in that
field as well.

Based-in-part-on-patch-by: Alexey Zaytsev <alexey.zaytsev@gmail.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
2010-12-15 13:58:18 -05:00
Lino Sanfilippo fdbf3ceeb6 fanotify: Dont try to open a file descriptor for the overflow event
We should not try to open a file descriptor for the overflow event since this
will always fail.

Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Signed-off-by: Eric Paris <eparis@redhat.com>
2010-12-07 16:14:24 -05:00
Eric Paris 2637919893 fanotify: do not leak user reference on allocation failure
If fanotify_init is unable to allocate a new fsnotify group it will
return but will not drop its reference on the associated user struct.
Drop that reference on error.

Reported-by: Vegard Nossum <vegard.nossum@gmail.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
2010-12-07 16:14:23 -05:00
Lino Sanfilippo 09e5f14e57 fanotify: on group destroy allow all waiters to bypass permission check
When fanotify_release() is called, there may still be processes waiting for
access permission. Currently only processes for which an event has already been
queued into the groups access list will be woken up.  Processes for which no
event has been queued will continue to sleep and thus cause a deadlock when
fsnotify_put_group() is called.
Furthermore there is a race allowing further processes to be waiting on the
access wait queue after wake_up (if they arrive before clear_marks_by_group()
is called).
This patch corrects this by setting a flag to inform processes that the group
is about to be destroyed and thus not to wait for access permission.

[additional changelog from eparis]
Lets think about the 4 relevant code paths from the PoV of the
'operator' 'listener' 'responder' and 'closer'.  Where operator is the
process doing an action (like open/read) which could require permission.
Listener is the task (or in this case thread) slated with reading from
the fanotify file descriptor.  The 'responder' is the thread responsible
for responding to access requests.  'Closer' is the thread attempting to
close the fanotify file descriptor.

The 'operator' is going to end up in:
fanotify_handle_event()
  get_response_from_access()
    (THIS BLOCKS WAITING ON USERSPACE)

The 'listener' interesting code path
fanotify_read()
  copy_event_to_user()
    prepare_for_access_response()
      (THIS CREATES AN fanotify_response_event)

The 'responder' code path:
fanotify_write()
  process_access_response()
    (REMOVE A fanotify_response_event, SET RESPONSE, WAKE UP 'operator')

The 'closer':
fanotify_release()
  (SUPPOSED TO CLEAN UP THE REST OF THIS MESS)

What we have today is that in the closer we remove all of the
fanotify_response_events and set a bit so no more response events are
ever created in prepare_for_access_response().

The bug is that we never wake all of the operators up and tell them to
move along.  You fix that in fanotify_get_response_from_access().  You
also fix other operators which haven't gotten there yet.  So I agree
that's a good fix.
[/additional changelog from eparis]

[remove additional changes to minimize patch size]
[move initialization so it was inside CONFIG_FANOTIFY_PERMISSION]

Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Signed-off-by: Eric Paris <eparis@redhat.com>
2010-12-07 16:14:22 -05:00
Lino Sanfilippo 1734dee4e3 fanotify: Dont allow a mask of 0 if setting or removing a mark
In mark_remove_from_mask() we destroy marks that have their event mask cleared.
Thus we should not allow the creation of those marks in the first place.
With this patch we check if the mask given from user is 0 in case of FAN_MARK_ADD.
If so we return an error. Same for FAN_MARK_REMOVE since this does not have any
effect.

Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Signed-off-by: Eric Paris <eparis@redhat.com>
2010-12-07 16:14:21 -05:00
Lino Sanfilippo fa218ab98c fanotify: correct broken ref counting in case adding a mark failed
If adding a mount or inode mark failed fanotify_free_mark() is called explicitly.
But at this time the mark has already been put into the destroy list of the
fsnotify_mark kernel thread. If the thread is too slow it will try to decrease
the reference of a mark, that has already been freed by fanotify_free_mark().
(If its fast enough it will only decrease the marks ref counter from 2 to 1 - note
that the counter has been increased to 2 in add_mark() - which has practically no
effect.)

This patch fixes the ref counting by not calling free_mark() explicitly, but
decreasing the ref counter and rely on the fsnotify_mark thread to cleanup in
case adding the mark has failed.

Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Signed-off-by: Eric Paris <eparis@redhat.com>
2010-12-07 16:14:21 -05:00
Eric Paris ecf6f5e7d6 fanotify: deny permissions when no event was sent
If no event was sent to userspace we cannot expect userspace to respond to
permissions requests.  Today such requests just hang forever. This patch will
deny any permissions event which was unable to be sent to userspace.

Reported-by: Tvrtko Ursulin <tvrtko.ursulin@sophos.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
2010-12-07 16:14:17 -05:00
Michael Witten 6aaccece1c Kconfig: typo: and -> an
Signed-off-by: Michael Witten <mfwitten@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2010-11-01 15:17:29 -04:00
Lino Sanfilippo 1a5cea7215 make fanotify_read() restartable across signals
In fanotify_read() return -ERESTARTSYS instead of -EINTR to
    make read() restartable across signals (BSD semantic).

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-10-30 14:07:35 -04:00
Andrew Morton 19ba54f464 fs/notify/fanotify/fanotify_user.c: fix warnings
fs/notify/fanotify/fanotify_user.c: In function 'fanotify_release':
fs/notify/fanotify/fanotify_user.c:375: warning: unused variable 'lre'
fs/notify/fanotify/fanotify_user.c:375: warning: unused variable 're'

this is really ugly.

Cc: Eric Paris <eparis@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Eric Paris <eparis@redhat.com>
2010-10-28 17:22:16 -04:00
Eric Paris 192ca4d194 fanotify: do not recalculate the mask if the ignored mask changed
If fanotify sets a new bit in the ignored mask it will cause the generic
fsnotify layer to recalculate the real mask.  This is stupid since we
didn't change that part.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-10-28 17:22:16 -04:00
Eric Paris 8fcd65280a fanotify: ignore events on directories unless specifically requested
fanotify has a very limited number of events it sends on directories.  The
usefulness of these events is yet to be seen and still we send them.  This
is particularly painful for mount marks where one might receive many of
these useless events.  As such this patch will drop events on IS_DIR()
inodes unless they were explictly requested with FAN_ON_DIR.

This means that a mark on a directory without FAN_EVENT_ON_CHILD or
FAN_ON_DIR is meaningless and will result in no events ever (although it
will still be allowed since detecting it is hard)

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-10-28 17:22:16 -04:00
Eric Paris e1c048ba78 fanotify: do not send events for irregular files
fanotify_should_send_event has a test to see if an object is a file or
directory and does not send an event otherwise.  The problem is that the
test is actually checking if the object with a mark is a file or directory,
not if the object the event happened on is a file or directory.  We should
check the latter.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-10-28 17:22:15 -04:00
Eric Paris 4afeff8505 fanotify: limit number of listeners per user
fanotify currently has no limit on the number of listeners a given user can
have open.  This patch limits the total number of listeners per user to
128.  This is the same as the inotify default limit.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-10-28 17:22:15 -04:00
Eric Paris ac7e22dcfa fanotify: allow userspace to override max marks
Some fanotify groups, especially those like AV scanners, will need to place
lots of marks, particularly ignore marks.  Since ignore marks do not pin
inodes in cache and are cleared if the inode is removed from core (usually
under memory pressure) we expose an interface for listeners, with
CAP_SYS_ADMIN, to override the maximum number of marks and be allowed to
set and 'unlimited' number of marks.  Programs which make use of this
feature will be able to OOM a machine.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-10-28 17:22:15 -04:00
Eric Paris e7099d8a5a fanotify: limit the number of marks in a single fanotify group
There is currently no limit on the number of marks a given fanotify group
can have.  Since fanotify is gated on CAP_SYS_ADMIN this was not seen as
a serious DoS threat.  This patch implements a default of 8192, the same as
inotify to work towards removing the CAP_SYS_ADMIN gating and eliminating
the default DoS'able status.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-10-28 17:22:14 -04:00
Eric Paris 5dd03f55fd fanotify: allow userspace to override max queue depth
fanotify has a defualt max queue depth.  This patch allows processes which
explicitly request it to have an 'unlimited' queue depth.  These processes
need to be very careful to make sure they cannot fall far enough behind
that they OOM the box.  Thus this flag is gated on CAP_SYS_ADMIN.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-10-28 17:22:14 -04:00
Eric Paris 2529a0df0f fsnotify: implement a default maximum queue depth
Currently fanotify has no maximum queue depth.  Since fanotify is
CAP_SYS_ADMIN only this does not pose a normal user DoS issue, but it
certianly is possible that an fanotify listener which can't keep up could
OOM the box.  This patch implements a default 16k depth.  This is the same
default depth used by inotify, but given fanotify's better queue merging in
many situations this queue will contain many additional useful events by
comparison.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-10-28 17:22:14 -04:00
Eric Paris 5322a59f14 fanotify: ignore fanotify ignore marks if open writers
fanotify will clear ignore marks if a task changes the contents of an
inode.  The problem is with the races around when userspace finishes
checking a file and when that result is actually attached to the inode.
This race was described as such:

Consider the following scenario with hostile processes A and B, and
victim process C:
1. Process A opens new file for writing. File check request is generated.
2. File check is performed in userspace. Check result is "file has no malware".
3. The "permit" response is delivered to kernel space.
4. File ignored mark set.
5. Process A writes dummy bytes to the file. File ignored flags are cleared.
6. Process B opens the same file for reading. File check request is generated.
7. File check is performed in userspace. Check result is "file has no malware".
8. Process A writes malware bytes to the file. There is no cached response yet.
9. The "permit" response is delivered to kernel space and is cached in fanotify.
10. File ignored mark set.
11. Now any process C will be permitted to open the malware file.
There is a race between steps 8 and 10

While fanotify makes no strong guarantees about systems with hostile
processes there is no reason we cannot harden against this race.  We do
that by simply ignoring any ignore marks if the inode has open writers (aka
i_writecount > 0).  (We actually do not ignore ignore marks if the
FAN_MARK_SURV_MODIFY flag is set)

Reported-by: Vasily Novikov <vasily.novikov@kaspersky.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
2010-10-28 17:22:14 -04:00
Eric Paris 4231a23530 fanotify: implement fanotify listener ordering
The fanotify listeners needs to be able to specify what types of operations
they are going to perform so they can be ordered appropriately between other
listeners doing other types of operations.  They need this to be able to make
sure that things like hierarchichal storage managers will get access to inodes
before processes which need the data.  This patch defines 3 possible uses
which groups must indicate in the fanotify_init() flags.

FAN_CLASS_PRE_CONTENT
FAN_CLASS_CONTENT
FAN_CLASS_NOTIF

Groups will receive notification in that order.  The order between 2 groups in
the same class is undeterministic.

FAN_CLASS_PRE_CONTENT is intended to be used by listeners which need access to
the inode before they are certain that the inode contains it's final data.  A
hierarchical storage manager should choose to use this class.

FAN_CLASS_CONTENT is intended to be used by listeners which need access to the
inode after it contains its intended contents.  This would be the appropriate
level for an AV solution or document control system.

FAN_CLASS_NOTIF is intended for normal async notification about access, much the
same as inotify and dnotify.  Syncronous permissions events are not permitted
at this class.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-10-28 17:22:13 -04:00
Arnd Bergmann 6038f373a3 llseek: automatically add .llseek fop
All file_operations should get a .llseek operation so we can make
nonseekable_open the default for future file operations without a
.llseek pointer.

The three cases that we can automatically detect are no_llseek, seq_lseek
and default_llseek. For cases where we can we can automatically prove that
the file offset is always ignored, we use noop_llseek, which maintains
the current behavior of not returning an error from a seek.

New drivers should normally not use noop_llseek but instead use no_llseek
and call nonseekable_open at open time.  Existing drivers can be converted
to do the same when the maintainer knows for certain that no user code
relies on calling seek on the device file.

The generated code is often incorrectly indented and right now contains
comments that clarify for each added line why a specific variant was
chosen. In the version that gets submitted upstream, the comments will
be gone and I will manually fix the indentation, because there does not
seem to be a way to do that using coccinelle.

Some amount of new code is currently sitting in linux-next that should get
the same modifications, which I will do at the end of the merge window.

Many thanks to Julia Lawall for helping me learn to write a semantic
patch that does all this.

===== begin semantic patch =====
// This adds an llseek= method to all file operations,
// as a preparation for making no_llseek the default.
//
// The rules are
// - use no_llseek explicitly if we do nonseekable_open
// - use seq_lseek for sequential files
// - use default_llseek if we know we access f_pos
// - use noop_llseek if we know we don't access f_pos,
//   but we still want to allow users to call lseek
//
@ open1 exists @
identifier nested_open;
@@
nested_open(...)
{
<+...
nonseekable_open(...)
...+>
}

@ open exists@
identifier open_f;
identifier i, f;
identifier open1.nested_open;
@@
int open_f(struct inode *i, struct file *f)
{
<+...
(
nonseekable_open(...)
|
nested_open(...)
)
...+>
}

@ read disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
<+...
(
   *off = E
|
   *off += E
|
   func(..., off, ...)
|
   E = *off
)
...+>
}

@ read_no_fpos disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
... when != off
}

@ write @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
<+...
(
  *off = E
|
  *off += E
|
  func(..., off, ...)
|
  E = *off
)
...+>
}

@ write_no_fpos @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
... when != off
}

@ fops0 @
identifier fops;
@@
struct file_operations fops = {
 ...
};

@ has_llseek depends on fops0 @
identifier fops0.fops;
identifier llseek_f;
@@
struct file_operations fops = {
...
 .llseek = llseek_f,
...
};

@ has_read depends on fops0 @
identifier fops0.fops;
identifier read_f;
@@
struct file_operations fops = {
...
 .read = read_f,
...
};

@ has_write depends on fops0 @
identifier fops0.fops;
identifier write_f;
@@
struct file_operations fops = {
...
 .write = write_f,
...
};

@ has_open depends on fops0 @
identifier fops0.fops;
identifier open_f;
@@
struct file_operations fops = {
...
 .open = open_f,
...
};

// use no_llseek if we call nonseekable_open
////////////////////////////////////////////
@ nonseekable1 depends on !has_llseek && has_open @
identifier fops0.fops;
identifier nso ~= "nonseekable_open";
@@
struct file_operations fops = {
...  .open = nso, ...
+.llseek = no_llseek, /* nonseekable */
};

@ nonseekable2 depends on !has_llseek @
identifier fops0.fops;
identifier open.open_f;
@@
struct file_operations fops = {
...  .open = open_f, ...
+.llseek = no_llseek, /* open uses nonseekable */
};

// use seq_lseek for sequential files
/////////////////////////////////////
@ seq depends on !has_llseek @
identifier fops0.fops;
identifier sr ~= "seq_read";
@@
struct file_operations fops = {
...  .read = sr, ...
+.llseek = seq_lseek, /* we have seq_read */
};

// use default_llseek if there is a readdir
///////////////////////////////////////////
@ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier readdir_e;
@@
// any other fop is used that changes pos
struct file_operations fops = {
... .readdir = readdir_e, ...
+.llseek = default_llseek, /* readdir is present */
};

// use default_llseek if at least one of read/write touches f_pos
/////////////////////////////////////////////////////////////////
@ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read.read_f;
@@
// read fops use offset
struct file_operations fops = {
... .read = read_f, ...
+.llseek = default_llseek, /* read accesses f_pos */
};

@ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write.write_f;
@@
// write fops use offset
struct file_operations fops = {
... .write = write_f, ...
+	.llseek = default_llseek, /* write accesses f_pos */
};

// Use noop_llseek if neither read nor write accesses f_pos
///////////////////////////////////////////////////////////

@ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
identifier write_no_fpos.write_f;
@@
// write fops use offset
struct file_operations fops = {
...
 .write = write_f,
 .read = read_f,
...
+.llseek = noop_llseek, /* read and write both use no f_pos */
};

@ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write_no_fpos.write_f;
@@
struct file_operations fops = {
... .write = write_f, ...
+.llseek = noop_llseek, /* write uses no f_pos */
};

@ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
@@
struct file_operations fops = {
... .read = read_f, ...
+.llseek = noop_llseek, /* read uses no f_pos */
};

@ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
@@
struct file_operations fops = {
...
+.llseek = noop_llseek, /* no read or write fn */
};
===== End semantic patch =====

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Julia Lawall <julia@diku.dk>
Cc: Christoph Hellwig <hch@infradead.org>
2010-10-15 15:53:27 +02:00
Andreas Gruenbacher a2f13ad0ba fanotify: Return EPERM when a process is not privileged
The appropriate error code when privileged operations are denied is
EPERM, not EACCES.

Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Signed-off-by: Eric Paris <paris@paris.rdu.redhat.com>
2010-08-27 19:59:42 -04:00
Tvrtko Ursulin ff8d6e9831 fanotify: drop duplicate pr_debug statement
This reminded me... you have two pr_debugs in fanotify_should_send_event
which output redundant information. Maybe you intended it like that so
it is selectable how much log spam you want, or if not you may want to
apply this patch.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@sophos.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
2010-08-22 20:30:12 -04:00
Eric Paris 2eebf582c9 fanotify: flush outstanding perm requests on group destroy
When an fanotify listener is closing it may cause a deadlock between the
listener and the original task doing an fs operation.  If the original task
is waiting for a permissions response it will be holding the srcu lock.  The
listener cannot clean up and exit until after that srcu lock is syncronized.
Thus deadlock.  The fix introduced here is to stop accepting new permissions
events when a listener is shutting down and to grant permission for all
outstanding events.  Thus the original task will eventually release the srcu
lock and the listener can complete shutdown.

Reported-by: Andreas Gruenbacher <agruen@suse.de>
Cc: Andreas Gruenbacher <agruen@suse.de>
Signed-off-by: Eric Paris <eparis@redhat.com>
2010-08-22 20:28:16 -04:00
Linus Torvalds 2069601b3f Revert "fsnotify: store struct file not struct path"
This reverts commit 3bcf3860a4 (and the
accompanying commit c1e5c95402 "vfs/fsnotify: fsnotify_close can delay
the final work in fput" that was a horribly ugly hack to make it work at
all).

The 'struct file' approach not only causes that disgusting hack, it
somehow breaks pulseaudio, probably due to some other subtlety with
f_count handling.

Fix up various conflicts due to later fsnotify work.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-12 14:23:04 -07:00
Eric Paris 1968f5eed5 fanotify: use both marks when possible
fanotify currently, when given a vfsmount_mark will look up (if it exists)
the corresponding inode mark.  This patch drops that lookup and uses the
mark provided.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 10:18:55 -04:00
Eric Paris ce8f76fb73 fsnotify: pass both the vfsmount mark and inode mark
should_send_event() and handle_event() will both need to look up the inode
event if they get a vfsmount event.  Lets just pass both at the same time
since we have them both after walking the lists in lockstep.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 10:18:54 -04:00
Eric Paris 43709a288e fsnotify: remove group->mask
group->mask is now useless.  It was originally a shortcut for fsnotify to
save on performance.  These checks are now redundant, so we remove them.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 10:18:54 -04:00
Eric Paris 2612abb51b fsnotify: cleanup should_send_event
The change to use srcu and walk the object list rather than the global
fsnotify_group list means that should_send_event is no longer needed for a
number of groups and can be simplified for others.  Do that.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 10:18:53 -04:00
Eric Paris 0215054f37 fanotify: use the mark in handler functions
fanotify now gets a mark in the should_send_event and handle_event
functions.  Rather than look up the mark themselves fanotify should just use
the mark it was handed.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 10:18:53 -04:00
Eric Paris 3a9b16b407 fsnotify: send fsnotify_mark to groups in event handling functions
With the change of fsnotify to use srcu walking the marks list instead of
walking the global groups list we now know the mark in question.  The code can
send the mark to the group's handling functions and the groups won't have to
find those marks themselves.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 10:18:52 -04:00
Eric Paris 3bcf3860a4 fsnotify: store struct file not struct path
Al explains that calling dentry_open() with a mnt/dentry pair is only
garunteed to be safe if they are already used in an open struct file.  To
make sure this is the case don't store and use a struct path in fsnotify,
always use a struct file.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 10:18:51 -04:00
Eric Paris f70ab54cc6 fsnotify: fsnotify_add_notify_event should return an event
Rather than the horrific void ** argument and such just to pass the
fanotify_merge event back to the caller of fsnotify_add_notify_event() have
those things return an event if it was different than the event suggusted to
be added.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 10:18:50 -04:00
Eric Paris 80af258867 fanotify: groups can specify their f_flags for new fd
Currently fanotify fds opened for thier listeners are done with f_flags
equal to O_RDONLY | O_LARGEFILE.  This patch instead takes f_flags from the
fanotify_init syscall and uses those when opening files in the context of
the listener.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 10:18:50 -04:00
Tejun Heo e4e047a220 fsnotify: update gfp/slab.h includes
Implicit slab.h inclusion via percpu.h is about to go away.  Make sure
gfp.h or slab.h is included as necessary.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Eric Paris <eparis@redhat.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:59:03 -04:00
Eric Paris 08ae89380a fanotify: drop the useless priority argument
The priority argument in fanotify is useless.  Kill it.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:59:03 -04:00
Eric Paris 269ed32a9c fanotify: default Kconfig to n
fanotify has default to y in linux-next since it's inception but default to
n in the final push to Linus.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:59:03 -04:00
Eric Paris 8860f060e4 fanotify: do not return 0 in a void function
remove_access_response() is supposed to have a void return, but was
returning 0;

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:59:02 -04:00
Eric Paris b2d879096a fanotify: userspace interface for permission responses
fanotify groups need to respond to events which include permissions types.
To do so groups will send a response using write() on the fanotify_fd they
have open.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:59:02 -04:00
Eric Paris 9e66e4233d fanotify: permissions and blocking
This is the backend work needed for fanotify to support the new
FS_OPEN_PERM and FS_ACCESS_PERM fsnotify events.  This is done using the
new fsnotify secondary queue.  No userspace interface is provided actually
respond to or request these events.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:59:02 -04:00
Eric Paris 43ed7e16a8 fanotify: use merge argument to determine actual event added to queue
fanotify needs to know the actual event added to queues so it can be
correctly checked for return values from userspace.  To do this we need to
pass that information from the merger code back to the main even handling
routine.  Currently that information is unused, but it will be.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:59:01 -04:00
Eric Paris 6e5f77b32e fsnotify: intoduce a notification merge argument
Each group can define their own notification (and secondary_q) merge
function.  Inotify does tail drop, fanotify does matching and drop which
can actually allocate a completely new event.  But for fanotify to properly
deal with permissions events it needs to know the new event which was
ultimately added to the notification queue.  This patch just implements a
void ** argument which is passed to the merge function.  fanotify can use
this field to pass the new event back to higher layers.

Signed-off-by: Eric Paris <eparis@redhat.com>
for fanotify to properly deal with permissions events
2010-07-28 09:59:01 -04:00
Eric Paris cb2d429faf fsnotify: add group priorities
This introduces an ordering to fsnotify groups.  With purely asynchronous
notification based "things" implementing fsnotify (inotify, dnotify) ordering
isn't particularly important.  But if people want to use fsnotify for the
basis of sycronous notification or blocking notification ordering becomes
important.

eg. A Hierarchical Storage Management listener would need to get its event
before an AV scanner could get its event (since the HSM would need to
bring the data in for the AV scanner to scan.)  Typically asynchronous notification
would want to run after the AV scanner made any relevant access decisions
so as to not send notification about an event that was denied.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:59:01 -04:00