Commit Graph

219 Commits

Author SHA1 Message Date
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
Eric Paris a2ae4cc9a1 inotify: stop kernel memory leak on file creation failure
If inotify_init is unable to allocate a new file for the new inotify
group we leak the new group.  This patch drops the reference on the
group on file allocation failure.

Reported-by: Vegard Nossum <vegard.nossum@gmail.com>
cc: stable@kernel.org
Signed-off-by: Eric Paris <eparis@redhat.com>
2010-12-07 16:14:22 -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
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 b29866aab8 fsnotify: rename FS_IN_ISDIR to FS_ISDIR
The _IN_ in the naming is reserved for flags only used by inotify.  Since I
am about to use this flag for fanotify rename it to be generic like the
rest.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-10-28 17:22:15 -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 52420392c8 fsnotify: call fsnotify_parent in perm events
fsnotify perm events do not call fsnotify parent.  That means you cannot
register a perm event on a directory and enforce permissions on all inodes in
that directory.  This patch fixes that situation.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-10-28 17:22:13 -04:00
Eric Paris ff8bcbd03d fsnotify: correctly handle return codes from listeners
When fsnotify groups return errors they are ignored.  For permissions
events these should be passed back up the stack, but for most events these
should continue to be ignored.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-10-28 17:22:13 -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
Eric Paris 6ad2d4e3e9 fsnotify: implement ordering between notifiers
fanotify needs to be able to specify that some groups get events before
others.  They use this idea to make sure that a hierarchical storage
manager gets access to files before programs which actually use them.  This
is purely infrastructure.  Everything will have a priority of 0, but the
infrastructure will exist for it to be non-zero.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-10-28 17:22:13 -04:00
Eric Paris 9343919c14 fanotify: allow fanotify to be built
We disabled the ability to build fanotify in commit 7c5347733d.
This reverts that commit and allows people to build fanotify.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-10-28 17:22:13 -04:00
Al Viro 63997e98a3 split invalidate_inodes()
Pull removal of fsnotify marks into generic_shutdown_super().
Split umount-time work into a new function - evict_inodes().
Make sure that invalidate_inodes() will be able to cope with
I_FREEING once we change locking in iput().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-10-25 21:27:18 -04:00
Christoph Hellwig 4d4eb36679 fsnotify: use dget_parent
Use dget_parent instead of opencoding it.  This simplifies the code, but
more importanly prepares for the more complicated locking for a parent
dget in the dcache scale patch series.

It means we do grab a reference to the parent now if need to be watched,
but not with the specified mask.  If this turns out to be a problem
we'll have to revisit it, but for now let's keep as much as possible
dcache internals inside dcache.[ch].

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-10-25 21:26:14 -04:00
Linus Torvalds 092e0e7e52 Merge branch 'llseek' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bkl
* 'llseek' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bkl:
  vfs: make no_llseek the default
  vfs: don't use BKL in default_llseek
  llseek: automatically add .llseek fop
  libfs: use generic_file_llseek for simple_attr
  mac80211: disallow seeks in minstrel debug code
  lirc: make chardev nonseekable
  viotape: use noop_llseek
  raw: use explicit llseek file operations
  ibmasmfs: use generic_file_llseek
  spufs: use llseek in all file operations
  arm/omap: use generic_file_llseek in iommu_debug
  lkdtm: use generic_file_llseek in debugfs
  net/wireless: use generic_file_llseek in debugfs
  drm: use noop_llseek
2010-10-22 10:52:56 -07:00
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
Eric Paris 7c5347733d fanotify: disable fanotify syscalls
This patch disables the fanotify syscalls by just not building them and
letting the cond_syscall() statements in kernel/sys_ni.c redirect them
to sys_ni_syscall().

It was pointed out by Tvrtko Ursulin that the fanotify interface did not
include an explicit prioritization between groups.  This is necessary
for fanotify to be usable for hierarchical storage management software,
as they must get first access to the file, before inotify-like notifiers
see the file.

This feature can be added in an ABI compatible way in the next release
(by using a number of bits in the flags field to carry the info) but it
was suggested by Alan that maybe we should just hold off and do it in
the next cycle, likely with an (new) explicit argument to the syscall.
I don't like this approach best as I know people are already starting to
use the current interface, but Alan is all wise and noone on list backed
me up with just using what we have.  I feel this is needlessly ripping
the rug out from under people at the last minute, but if others think it
needs to be a new argument it might be the best way forward.

Three choices:
Go with what we got (and implement the new feature next cycle).  Add a
new field right now (and implement the new feature next cycle).  Wait
till next cycle to release the ABI (and implement the new feature next
cycle).  This is number 3.

Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-11 18:15:28 -07:00
Eric Paris 92b4678efa fsnotify: drop two useless bools in the fnsotify main loop
The fsnotify main loop has 2 bools which indicated if we processed the
inode or vfsmount mark in that particular pass through the loop.  These
bool can we replaced with the inode_group and vfsmount_group variables
and actually make the code a little easier to understand.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-08-27 21:42:11 -04:00
Eric Paris f72adfd540 fsnotify: fix list walk order
Marks were stored on the inode and vfsmonut mark list in order from
highest memory address to lowest memory address.  The code to walk those
lists thought they were in order from lowest to highest with
unpredictable results when trying to match up marks from each.  It was
possible that extra events would be sent to userspace when inode
marks ignoring events wouldn't get matched with the vfsmount marks.

This problem only affected fanotify when using both vfsmount and inode
marks simultaneously.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-08-27 21:41:26 -04:00
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
Eric Paris 84e1ab4d87 fsnotify: fix ignored mask handling between inode and vfsmount marks
The interesting 2 list lockstep walking didn't quite work out if the inode
marks only had ignores and the vfsmount list requested events.  The code to
shortcut list traversal would not run the inode list since it didn't have real
event requests.  This code forces inode list traversal when a vfsmount mark
matches the event type.  Maybe we could add an i_fsnotify_ignored_mask field
to struct inode to get the shortcut back, but it doesn't seem worth it to grow
struct inode again.

I bet with the recent changes to lock the way we do now it would actually not
be a major perf hit to just drop i_fsnotify_mark_mask altogether.  But that is
for another day.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-08-22 20:09:41 -04:00
Eric Paris 5f3f259fa8 fsnotify: reset used_inode and used_vfsmount on each pass
The fsnotify main loop has 2 booleans which tell if a particular mark was
sent to the listeners or if it should be processed in the next pass.  The
problem is that the booleans were not reset on each traversal of the loop.
So marks could get skipped even when they were not sent to the notifiers.

Reported-by: Tvrtko Ursulin <tvrtko.ursulin@sophos.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
2010-08-22 20:09:41 -04:00
Eric Paris faa9560ae7 fanotify: do not dereference inode_mark when it is unset
The fanotify code is supposed to get the group from the mark.  It accidentally
only used the inode_mark.  If the vfsmount_mark was set but not the inode_mark
it would deref the NULL inode_mark.  Get the group from the correct place.

Reported-by: Tvrtko Ursulin <tvrtko.ursulin@sophos.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
2010-08-22 20:09:41 -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
Linus Torvalds 8c8946f509 Merge branch 'for-linus' of git://git.infradead.org/users/eparis/notify
* 'for-linus' of git://git.infradead.org/users/eparis/notify: (132 commits)
  fanotify: use both marks when possible
  fsnotify: pass both the vfsmount mark and inode mark
  fsnotify: walk the inode and vfsmount lists simultaneously
  fsnotify: rework ignored mark flushing
  fsnotify: remove global fsnotify groups lists
  fsnotify: remove group->mask
  fsnotify: remove the global masks
  fsnotify: cleanup should_send_event
  fanotify: use the mark in handler functions
  audit: use the mark in handler functions
  dnotify: use the mark in handler functions
  inotify: use the mark in handler functions
  fsnotify: send fsnotify_mark to groups in event handling functions
  fsnotify: Exchange list heads instead of moving elements
  fsnotify: srcu to protect read side of inode and vfsmount locks
  fsnotify: use an explicit flag to indicate fsnotify_destroy_mark has been called
  fsnotify: use _rcu functions for mark list traversal
  fsnotify: place marks on object in order of group memory address
  vfs/fsnotify: fsnotify_close can delay the final work in fput
  fsnotify: store struct file not struct path
  ...

Fix up trivial delete/modify conflict in fs/notify/inotify/inotify.c.
2010-08-10 11:39:13 -07:00
Al Viro a4ffdde6e5 simplify checks for I_CLEAR/I_FREEING
add I_CLEAR instead of replacing I_FREEING with it.  I_CLEAR is
equivalent to I_FREEING for almost all code looking at either;
it's there to keep track of having called clear_inode() exactly
once per inode lifetime, at some point after having set I_FREEING.
I_CLEAR and I_FREEING never get set at the same time with the
current code, so we can switch to setting i_flags to I_FREEING | I_CLEAR
instead of I_CLEAR without loss of information.  As the result of
such change, checks become simpler and the amount of code that needs
to know about I_CLEAR shrinks a lot.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-08-09 16:47:44 -04:00
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 613a807fe7 fsnotify: walk the inode and vfsmount lists simultaneously
We currently walk the list of marks on an inode followed by the list of
marks on the vfsmount.  These are in order (by the memory address of the
group) so lets walk them both together.  Eventually we can pass both the
inode mark and the vfsmount mark to helpers simultaneously.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 10:18:54 -04:00
Eric Paris 84a5b68e8d fsnotify: rework ignored mark flushing
currently ignored_mark clearing is done in a seperate list traversal
before the actual list traversal to send events.  There is no need for
this.  Do them at the same time.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 10:18:54 -04:00
Eric Paris 02436668d9 fsnotify: remove global fsnotify groups lists
The global fsnotify groups lists were invented as a way to increase the
performance of fsnotify by shortcutting events which were not interesting.
With the changes to walk the object lists rather than global groups lists
these shortcuts are not useful.

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 03930979af fsnotify: remove the global masks
Because we walk the object->fsnotify_marks list instead of the global
fsnotify groups list we don't need the fsnotify_inode_mask and
fsnotify_vfsmount_mask as these were simply shortcuts in fsnotify() for
performance.  They are now extra checks, rip them out.

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