Commit Graph

48 Commits

Author SHA1 Message Date
Jan Kara 56b27cf603 fsnotify: remove pointless NULL initializers
We usually rely on the fact that struct members not specified in the
initializer are set to NULL.  So do that with fsnotify function pointers
as well.

Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Eric Paris <eparis@parisplace.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:41 -08:00
Jan Kara 83c4c4b0a3 fsnotify: remove .should_send_event callback
After removing event structure creation from the generic layer there is
no reason for separate .should_send_event and .handle_event callbacks.
So just remove the first one.

Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Eric Paris <eparis@parisplace.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:41 -08:00
Jan Kara 7053aee26a fsnotify: do not share events between notification groups
Currently fsnotify framework creates one event structure for each
notification event and links this event into all interested notification
groups.  This is done so that we save memory when several notification
groups are interested in the event.  However the need for event
structure shared between inotify & fanotify bloats the event structure
so the result is often higher memory consumption.

Another problem is that fsnotify framework keeps path references with
outstanding events so that fanotify can return open file descriptors
with its events.  This has the undesirable effect that filesystem cannot
be unmounted while there are outstanding events - a regression for
inotify compared to a situation before it was converted to fsnotify
framework.  For fanotify this problem is hard to avoid and users of
fanotify should kind of expect this behavior when they ask for file
descriptors from notified files.

This patch changes fsnotify and its users to create separate event
structure for each group.  This allows for much simpler code (~400 lines
removed by this patch) and also smaller event structures.  For example
on 64-bit system original struct fsnotify_event consumes 120 bytes, plus
additional space for file name, additional 24 bytes for second and each
subsequent group linking the event, and additional 32 bytes for each
inotify group for private data.  After the conversion inotify event
consumes 48 bytes plus space for file name which is considerably less
memory unless file names are long and there are several groups
interested in the events (both of which are uncommon).  Fanotify event
fits in 56 bytes after the conversion (fanotify doesn't care about file
names so its events don't have to have it allocated).  A win unless
there are four or more fanotify groups interested in the event.

The conversion also solves the problem with unmount when only inotify is
used as we don't have to grab path references for inotify events.

[hughd@google.com: fanotify: fix corruption preventing startup]
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Eric Paris <eparis@parisplace.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:41 -08:00
Chen Gang 736f3203a0 kernel/audit_tree.c:audit_add_tree_rule(): protect `rule' from kill_rules()
audit_add_tree_rule() must set 'rule->tree = NULL;' firstly, to protect
the rule itself freed in kill_rules().

The reason is when it is killed, the 'rule' itself may have already
released, we should not access it.  one example: we add a rule to an
inode, just at the same time the other task is deleting this inode.

The work flow for adding a rule:

    audit_receive() -> (need audit_cmd_mutex lock)
      audit_receive_skb() ->
        audit_receive_msg() ->
          audit_receive_filter() ->
            audit_add_rule() ->
              audit_add_tree_rule() -> (need audit_filter_mutex lock)
                ...
                unlock audit_filter_mutex
                get_tree()
                ...
                iterate_mounts() -> (iterate all related inodes)
                  tag_mount() ->
                    tag_trunk() ->
                      create_trunk() -> (assume it is 1st rule)
                        fsnotify_add_mark() ->
                          fsnotify_add_inode_mark() ->  (add mark to inode->i_fsnotify_marks)
                        ...
                        get_tree(); (each inode will get one)
                ...
                lock audit_filter_mutex

The work flow for deleting an inode:

    __destroy_inode() ->
     fsnotify_inode_delete() ->
       __fsnotify_inode_delete() ->
        fsnotify_clear_marks_by_inode() ->  (get mark from inode->i_fsnotify_marks)
          fsnotify_destroy_mark() ->
           fsnotify_destroy_mark_locked() ->
             audit_tree_freeing_mark() ->
               evict_chunk() ->
                 ...
                 tree->goner = 1
                 ...
                 kill_rules() ->   (assume current->audit_context == NULL)
                   call_rcu() ->   (rule->tree != NULL)
                     audit_free_rule_rcu() ->
                       audit_free_rule()
                 ...
                 audit_schedule_prune() ->  (assume current->audit_context == NULL)
                   kthread_run() ->    (need audit_cmd_mutex and audit_filter_mutex lock)
                     prune_one() ->    (delete it from prue_list)
                       put_tree(); (match the original get_tree above)

Signed-off-by: Chen Gang <gang.chen@asianux.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-06-12 16:29:46 -07:00
Chen Gang 12b2f117f3 kernel/audit_tree.c: tree will leak memory when failure occurs in audit_trim_trees()
audit_trim_trees() calls get_tree().  If a failure occurs we must call
put_tree().

[akpm@linux-foundation.org: run put_tree() before mutex_lock() for small scalability improvement]
Signed-off-by: Chen Gang <gang.chen@asianux.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric Paris <eparis@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:26 -07:00
Kees Cook 0644ec0cc8 audit: catch possible NULL audit buffers
It's possible for audit_log_start() to return NULL.  Handle it in the
various callers.

Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric Paris <eparis@redhat.com>
Cc: Jeff Layton <jlayton@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Julien Tinnes <jln@google.com>
Cc: Will Drewry <wad@google.com>
Cc: Steve Grubb <sgrubb@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-01-11 14:54:55 -08:00
Lino Sanfilippo e2a29943e9 fsnotify: pass group to fsnotify_destroy_mark()
In fsnotify_destroy_mark() dont get the group from the passed mark anymore,
but pass the group itself as an additional parameter to the function.

Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Signed-off-by: Eric Paris <eparis@redhat.com>
2012-12-11 13:44:36 -05:00
Miklos Szeredi b3e8692b4d audit: clean up refcounting in audit-tree
Drop the initial reference by fsnotify_init_mark early instead of
audit_tree_freeing_mark() at destroy time.

In the cases we destroy the mark before we drop the initial reference we need to
get rid of the get_mark that balances the put_mark in audit_tree_freeing_mark().

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2012-08-15 12:55:22 +02:00
Miklos Szeredi a2140fc0cb audit: fix refcounting in audit-tree
Refcounting of fsnotify_mark in audit tree is broken.  E.g:

                              refcount
create_chunk
  alloc_chunk                 1
  fsnotify_add_mark           2

untag_chunk
  fsnotify_get_mark           3
  fsnotify_destroy_mark
    audit_tree_freeing_mark   2
  fsnotify_put_mark           1
  fsnotify_put_mark           0
  via destroy_list
    fsnotify_mark_destroy    -1

This was reported by various people as triggering Oops when stopping auditd.

We could just remove the put_mark from audit_tree_freeing_mark() but that would
break freeing via inode destruction.  So this patch simply omits a put_mark
after calling destroy_mark or adds a get_mark before.

The additional get_mark is necessary where there's no other put_mark after
fsnotify_destroy_mark() since it assumes that the caller is holding a reference
(or the inode is keeping the mark pinned, not the case here AFAICS).

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reported-by: Valentin Avram <aval13@gmail.com>
Reported-by: Peter Moody <pmoody@google.com>
Acked-by: Eric Paris <eparis@redhat.com>
CC: stable@vger.kernel.org
2012-08-15 12:55:22 +02:00
Miklos Szeredi 0fe33aae0e audit: don't free_chunk() after fsnotify_add_mark()
Don't do free_chunk() after fsnotify_add_mark().  That one does a delayed unref
via the destroy list and this results in use-after-free.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Acked-by: Eric Paris <eparis@redhat.com>
CC: stable@vger.kernel.org
2012-08-15 12:55:22 +02:00
David Howells be34d1a3bc VFS: Make clone_mnt()/copy_tree()/collect_mounts() return errors
copy_tree() can theoretically fail in a case other than ENOMEM, but always
returns NULL which is interpreted by callers as -ENOMEM.  Change it to return
an explicit error.

Also change clone_mnt() for consistency and because union mounts will add new
error cases.

Thanks to Andreas Gruenbacher <agruen@suse.de> for a bug fix.
[AV: folded braino fix by Dan Carpenter]

Original-author: Valerie Aurora <vaurora@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Valerie Aurora <valerie.aurora@gmail.com>
Cc: Andreas Gruenbacher <agruen@suse.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-14 16:37:27 +04:00
Lai Jiangshan 3b097c4696 audit_tree,rcu: Convert call_rcu(__put_tree) to kfree_rcu()
The rcu callback __put_tree() just calls a kfree(),
so we use kfree_rcu() instead of the call_rcu(__put_tree).

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric Paris <eparis@redhat.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-07-20 14:10:11 -07:00
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
Al Viro f7a998a949 in untag_chunk() we need to do alloc_chunk() a bit earlier
... while we are not holding spinlocks.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-10-30 02:18:32 -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 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 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 5444e2981c fsnotify: split generic and inode specific mark code
currently all marking is done by functions in inode-mark.c.  Some of this
is pretty generic and should be instead done in a generic function and we
should only put the inode specific code in inode-mark.c

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:58:57 -04:00
Andreas Gruenbacher 3556608709 fsnotify: take inode->i_lock inside fsnotify_find_mark_entry()
All callers to fsnotify_find_mark_entry() except one take and
release inode->i_lock around the call.  Take the lock inside
fsnotify_find_mark_entry() instead.

Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:58:54 -04:00
Eric Paris d07754412f fsnotify: rename fsnotify_find_mark_entry to fsnotify_find_mark
the _entry portion of fsnotify functions is useless.  Drop it.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:58:53 -04:00
Eric Paris e61ce86737 fsnotify: rename fsnotify_mark_entry to just fsnotify_mark
The name is long and it serves no real purpose.  So rename
fsnotify_mark_entry to just fsnotify_mark.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:58:53 -04:00
Eric Paris 2823e04de4 fsnotify: put inode specific fields in an fsnotify_mark in a union
The addition of marks on vfs mounts will be simplified if the inode
specific parts of a mark and the vfsmnt specific parts of a mark are
actually in a union so naming can be easy.  This patch just implements the
inode struct and the union.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:58:52 -04:00
Eric Paris 3a9fb89f4c fsnotify: include vfsmount in should_send_event when appropriate
To ensure that a group will not duplicate events when it receives it based
on the vfsmount and the inode should_send_event test we should distinguish
those two cases.  We pass a vfsmount to this function so groups can make
their own determinations.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:58:52 -04:00
Eric Paris 0d2e2a1d00 fsnotify: drop mask argument from fsnotify_alloc_group
Nothing uses the mask argument to fsnotify_alloc_group.  This patch drops
that argument.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:58:51 -04:00
Eric Paris ffab83402f fsnotify: fsnotify_obtain_group should be fsnotify_alloc_group
fsnotify_obtain_group was intended to be able to find an already existing
group.  Nothing uses that functionality.  This just renames it to
fsnotify_alloc_group so it is clear what it is doing.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:58:50 -04:00
Eric Paris 74be0cc828 fsnotify: remove group_num altogether
The original fsnotify interface has a group-num which was intended to be
able to find a group after it was added.  I no longer think this is a
necessary thing to do and so we remove the group_num.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:58:50 -04:00
Eric Paris 8112e2d6a7 fsnotify: include data in should_send calls
fanotify is going to need to look at file->private_data to know if an event
should be sent or not.  This passes the data (which might be a file,
dentry, inode, or none) to the should_send function calls so fanotify can
get that information when available

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:58:31 -04:00
Eric Paris 7b0a04fbfb fsnotify: provide the data type to should_send_event
fanotify is only interested in event types which contain enough information
to open the original file in the context of the fanotify listener.  Since
fanotify may not want to send events if that data isn't present we pass
the data type to the should_send_event function call so fanotify can express
its lack of interest.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:58:31 -04:00
Eric Paris 28a3a7eb3b audit: reimplement audit_trees using fsnotify rather than inotify
Simply switch audit_trees from using inotify to using fsnotify for it's
inode pinning and disappearing act information.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:58:17 -04:00
Tejun Heo 5a0e3ad6af include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-30 22:02:32 +09:00
Al Viro 1f707137b5 new helper: iterate_mounts()
apply function to vfsmounts in set returned by collect_mounts(),
stop if it returns non-zero.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-03-03 14:07:57 -05:00
Al Viro 2096f759ab New helper: path_is_under(path1, path2)
Analog of is_subdir for vfsmount,dentry pairs, moved from audit_tree.c

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-03-03 14:07:55 -05:00
Al Viro b4c30aad39 fix more leaks in audit_tree.c tag_chunk()
Several leaks in audit_tree didn't get caught by commit
318b6d3d7d, including the leak on normal
exit in case of multiple rules refering to the same chunk.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-19 09:27:43 -08:00
Al Viro 6f5d511489 fix braindamage in audit_tree.c untag_chunk()
... aka "Al had badly fscked up when writing that thing and nobody
noticed until Eric had fixed leaks that used to mask the breakage".

The function essentially creates a copy of old array sans one element
and replaces the references to elements of original (they are on cyclic
lists) with those to corresponding elements of new one.  After that the
old one is fair game for freeing.

First of all, there's a dumb braino: when we get to list_replace_init we
use indices for wrong arrays - position in new one with the old array
and vice versa.

Another bug is more subtle - termination condition is wrong if the
element to be excluded happens to be the last one.  We shouldn't go
until we fill the new array, we should go until we'd finished the old
one.  Otherwise the element we are trying to kill will remain on the
cyclic lists...

That crap used to be masked by several leaks, so it was not quite
trivial to hit.  Eric had fixed some of those leaks a while ago and the
shit had hit the fan...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-19 09:27:43 -08:00
Al Viro 916d75761c Fix rule eviction order for AUDIT_DIR
If syscall removes the root of subtree being watched, we
definitely do not want the rules refering that subtree
to be destroyed without the syscall in question having
a chance to match them.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-24 00:02:38 -04:00
Eric Paris 9d96098510 Audit: clean up all op= output to include string quoting
A number of places in the audit system we send an op= followed by a string
that includes spaces.  Somehow this works but it's just wrong.  This patch
moves all of those that I could find to be quoted.

Example:

Change From: type=CONFIG_CHANGE msg=audit(1244666690.117:31): auid=0 ses=1
subj=unconfined_u:unconfined_r:auditctl_t:s0-s0:c0.c1023 op=remove rule
key="number2" list=4 res=0

Change To: type=CONFIG_CHANGE msg=audit(1244666690.117:31): auid=0 ses=1
subj=unconfined_u:unconfined_r:auditctl_t:s0-s0:c0.c1023 op="remove rule"
key="number2" list=4 res=0

Signed-off-by: Eric Paris <eparis@redhat.com>
2009-06-24 00:00:52 -04:00
Al Viro 589ff870ed Switch collect_mounts() to struct path
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-11 21:36:01 -04:00
Al Viro 24b6f16ecf No need for crossing to mountpoint in audit_tag_tree()
is_under() will DTRT anyway.  And yes, is_subdir() behaviour
is intentional.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-04-20 23:01:15 -04:00
Eric Paris 318b6d3d7d audit: incorrect ref counting in audit tree tag_chunk
tag_chunk has bad exit paths in which the inotify ref counting is wrong.
At the top of the function we found &old_watch using  inotify_find_watch().
inotify_find_watch takes a reference to the watch.  This is never dropped
on an error path.

Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-04-05 13:48:26 -04:00
Al Viro 5af75d8d58 audit: validate comparison operations, store them in sane form
Don't store the field->op in the messy (and very inconvenient for e.g.
audit_comparator()) form; translate to dense set of values and do full
validation of userland-submitted value while we are at it.

->audit_init_rule() and ->audit_match_rule() get new values now; in-tree
instances updated.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-01-04 15:14:42 -05:00
Al Viro e45aa212ea audit rules ordering, part 2
Fix the actual rule listing; add per-type lists _not_ used for matching,
with all exit,... sitting on one such list.  Simplifies "do something
for all rules" logics, while we are at it...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-01-04 15:14:42 -05:00
Al Viro 8f7b0ba1c8 Fix inotify watch removal/umount races
Inotify watch removals suck violently.

To kick the watch out we need (in this order) inode->inotify_mutex and
ih->mutex.  That's fine if we have a hold on inode; however, for all
other cases we need to make damn sure we don't race with umount.  We can
*NOT* just grab a reference to a watch - inotify_unmount_inodes() will
happily sail past it and we'll end with reference to inode potentially
outliving its superblock.

Ideally we just want to grab an active reference to superblock if we
can; that will make sure we won't go into inotify_umount_inodes() until
we are done.  Cleanup is just deactivate_super().

However, that leaves a messy case - what if we *are* racing with
umount() and active references to superblock can't be acquired anymore?
We can bump ->s_count, grab ->s_umount, which will almost certainly wait
until the superblock is shut down and the watch in question is pining
for fjords.  That's fine, but there is a problem - we might have hit the
window between ->s_active getting to 0 / ->s_count - below S_BIAS (i.e.
the moment when superblock is past the point of no return and is heading
for shutdown) and the moment when deactivate_super() acquires
->s_umount.

We could just do drop_super() yield() and retry, but that's rather
antisocial and this stuff is luser-triggerable.  OTOH, having grabbed
->s_umount and having found that we'd got there first (i.e.  that
->s_root is non-NULL) we know that we won't race with
inotify_umount_inodes().

So we could grab a reference to watch and do the rest as above, just
with drop_super() instead of deactivate_super(), right? Wrong.  We had
to drop ih->mutex before we could grab ->s_umount.  So the watch
could've been gone already.

That still can be dealt with - we need to save watch->wd, do idr_find()
and compare its result with our pointer.  If they match, we either have
the damn thing still alive or we'd lost not one but two races at once,
the watch had been killed and a new one got created with the same ->wd
at the same address.  That couldn't have happened in inotify_destroy(),
but inotify_rm_wd() could run into that.  Still, "new one got created"
is not a problem - we have every right to kill it or leave it alone,
whatever's more convenient.

So we can use idr_find(...) == watch && watch->inode->i_sb == sb as
"grab it and kill it" check.  If it's been our original watch, we are
fine, if it's a newcomer - nevermind, just pretend that we'd won the
race and kill the fscker anyway; we are safe since we know that its
superblock won't be going away.

And yes, this is far beyond mere "not very pretty"; so's the entire
concept of inotify to start with.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Greg KH <greg@kroah.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-11-15 12:26:44 -08:00
Al Viro 98bc993f99 [PATCH] get rid of nameidata in audit_tree
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-10-23 05:12:53 -04:00
Paul E. McKenney 6793a051fb [PATCH] list_for_each_rcu must die: audit
All uses of list_for_each_rcu() can be profitably replaced by the
easier-to-use list_for_each_entry_rcu().  This patch makes this change
for the Audit system, in preparation for removing the list_for_each_rcu()
API entirely.  This time with well-formed SOB.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-05-17 03:30:23 -04:00
Jan Blunck 1d957f9bf8 Introduce path_put()
* Add path_put() functions for releasing a reference to the dentry and
  vfsmount of a struct path in the right order

* Switch from path_release(nd) to path_put(&nd->path)

* Rename dput_path() to path_put_conditional()

[akpm@linux-foundation.org: fix cifs]
Signed-off-by: Jan Blunck <jblunck@suse.de>
Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: <linux-fsdevel@vger.kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Steven French <sfrench@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-14 21:13:33 -08:00
Jan Blunck 4ac9137858 Embed a struct path into struct nameidata instead of nd->{dentry,mnt}
This is the central patch of a cleanup series. In most cases there is no good
reason why someone would want to use a dentry for itself. This series reflects
that fact and embeds a struct path into nameidata.

Together with the other patches of this series
- it enforced the correct order of getting/releasing the reference count on
  <dentry,vfsmount> pairs
- it prepares the VFS for stacking support since it is essential to have a
  struct path in every place where the stack can be traversed
- it reduces the overall code size:

without patch series:
   text    data     bss     dec     hex filename
5321639  858418  715768 6895825  6938d1 vmlinux

with patch series:
   text    data     bss     dec     hex filename
5320026  858418  715768 6894212  693284 vmlinux

This patch:

Switch from nd->{dentry,mnt} to nd->path.{dentry,mnt} everywhere.

[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: fix cifs]
[akpm@linux-foundation.org: fix smack]
Signed-off-by: Jan Blunck <jblunck@suse.de>
Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-14 21:13:33 -08:00
Al Viro 74c3cbe33b [PATCH] audit: watching subtrees
New kind of audit rule predicates: "object is visible in given subtree".
The part that can be sanely implemented, that is.  Limitations:
	* if you have hardlink from outside of tree, you'd better watch
it too (or just watch the object itself, obviously)
	* if you mount something under a watched tree, tell audit
that new chunk should be added to watched subtrees
	* if you umount something in a watched tree and it's still mounted
elsewhere, you will get matches on events happening there.  New command
tells audit to recalculate the trees, trimming such sources of false
positives.

Note that it's _not_ about path - if something mounted in several places
(multiple mount, bindings, different namespaces, etc.), the match does
_not_ depend on which one we are using for access.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2007-10-21 02:37:45 -04:00