Make sure compiler won't do weird things with limits.  E.g.  fetching them
twice may return 2 different values after writable limits are implemented.

I.e.  either use rlimit helpers added in
3e10e716 ("resource: add helpers for
fetching rlimits") or ACCESS_ONCE if not applicable.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NAndré Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

... postponing assignments until they're needed. Doesn't change code size.
Signed-off-by: NAndré Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

It reduces code size:
text    data     bss     dec     hex filename
9925      72      16   10013    271d ipc/mqueue-BEFORE.o
9885      72      16    9973    26f5 ipc/mqueue-AFTER.o
Signed-off-by: NAndré Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Code size reduction:
   text    data     bss     dec     hex filename
   9941      72      16   10029    272d ipc/mqueue-BEFORE.o
   9925      72      16   10013    271d ipc/mqueue-AFTER.o
Signed-off-by: NAndré Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

... and abort earlier if we couldn't allocate the message pointers array,
avoiding the u->mq_bytes accounting logic.

It reduces code size:
   text    data     bss     dec     hex filename
   9949      72      16   10037    2735 ipc/mqueue-BEFORE.o
   9941      72      16   10029    272d ipc/mqueue-AFTER.o
Signed-off-by: NAndré Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

We leak fd on lookup_one_len() failure
Signed-off-by: NAndré Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

* do ima_get_count() in __dentry_open()
* stop doing that in followups
* move ima_path_check() to right after nameidata_to_filp()
* don't bump counters on it
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch fixes an imbalance message as reported by Sanchin Sant.
As we don't need to measure the message queue, just increment the
counters.
Reported-by: NSanchin Sant <sanchinp@in.ibm.com>
Signed-off-by: NMimi Zohar <zohar@us.ibm.com>
Acked-by: NSerge Hallyn <serue@us.ibm.com>
Signed-off-by: NJames Morris <jmorris@namei.org>

Largely inspired from ipc/ipc_sysctl.c.  This patch isolates the mqueue
sysctl stuff in its own file.

[akpm@linux-foundation.org: build fix]
Signed-off-by: NCedric Le Goater <clg@fr.ibm.com>
Signed-off-by: NNadia Derbey <Nadia.Derbey@bull.net>
Signed-off-by: NSerge E. Hallyn <serue@us.ibm.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Implement multiple mounts of the mqueue file system, and link it to usage
of CLONE_NEWIPC.

Each ipc ns has a corresponding mqueuefs superblock.  When a user does
clone(CLONE_NEWIPC) or unshare(CLONE_NEWIPC), the unshare will cause an
internal mount of a new mqueuefs sb linked to the new ipc ns.

When a user does 'mount -t mqueue mqueue /dev/mqueue', he mounts the
mqueuefs superblock.

Posix message queues can be worked with both through the mq_* system calls
(see mq_overview(7)), and through the VFS through the mqueue mount.  Any
usage of mq_open() and friends will work with the acting task's ipc
namespace.  Any actions through the VFS will work with the mqueuefs in
which the file was created.  So if a user doesn't remount mqueuefs after
unshare(CLONE_NEWIPC), mq_open("/ab") will not be reflected in "ls
/dev/mqueue".

If task a mounts mqueue for ipc_ns:1, then clones task b with a new ipcns,
ipcns:2, and then task a is the last task in ipc_ns:1 to exit, then (1)
ipc_ns:1 will be freed, (2) it's superblock will live on until task b
umounts the corresponding mqueuefs, and vfs actions will continue to
succeed, but (3) sb->s_fs_info will be NULL for the sb corresponding to
the deceased ipc_ns:1.

To make this happen, we must protect the ipc reference count when

a) a task exits and drops its ipcns->count, since it might be dropping
   it to 0 and freeing the ipcns

b) a task accesses the ipcns through its mqueuefs interface, since it
   bumps the ipcns refcount and might race with the last task in the ipcns
   exiting.

So the kref is changed to an atomic_t so we can use
atomic_dec_and_lock(&ns->count,mq_lock), and every access to the ipcns
through ns = mqueuefs_sb->s_fs_info is protected by the same lock.
Signed-off-by: NCedric Le Goater <clg@fr.ibm.com>
Signed-off-by: NSerge E. Hallyn <serue@us.ibm.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Move mqueue vfsmount plus a few tunables into the ipc_namespace struct.
The CONFIG_IPC_NS boolean and the ipc_namespace struct will serve both the
posix message queue namespaces and the SYSV ipc namespaces.

The sysctl code will be fixed separately in patch 3.  After just this
patch, making a change to posix mqueue tunables always changes the values
in the initial ipc namespace.
Signed-off-by: NCedric Le Goater <clg@fr.ibm.com>
Signed-off-by: NSerge E. Hallyn <serue@us.ibm.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

current->fs->umask is what most of fs_struct users are doing.
Put that into a helper function.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Traditionally, changes to struct file->f_flags have been done under BKL
protection, or with no protection at all.  This patch causes all f_flags
changes after file open/creation time to be done under protection of
f_lock.  This allows the removal of some BKL usage and fixes a number of
longstanding (if microscopic) races.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>

Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>

Convert all system calls to return a long. This should be a NOP since all
converted types should have the same size anyway.
With the exception of sys_exit_group which returned void. But that doesn't
matter since the system call doesn't return.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>

If a process registers for asynchronous notification on a POSIX message
queue, it gets a signal and a siginfo_t structure when a message arrives
on the message queue.  The si_pid in the siginfo_t structure is set to the
PID of the process that sent the message to the message queue.

The principle is the following:
. when mq_notify(SIGEV_SIGNAL) is called, the caller registers for
  notification when a msg arrives. The associated pid structure is stroed into
  inode_info->notify_owner. Let's call this process P1.
. when mq_send() is called by say P2, P2 sends a signal to P1 to notify
  him about msg arrival.

The way .si_pid is set today is not correct, since it doesn't take into account
the fact that the process that is sending the message might not be in the
same namespace as the notified one.

This patch proposes to set si_pid to the sender's pid into the notify_owner
namespace.
Signed-off-by: NNadia Derbey <Nadia.Derbey@bull.net>
Signed-off-by: NSukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Acked-by: NOleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Bastian Blank <bastian@waldi.eu.org>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: NSerge Hallyn <serue@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

... and don't bother in callers.  Don't bother with zeroing i_blocks,
while we are at it - it's already been zeroed.

i_mode is not worth the effort; it has no common default value.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

* don't bother with allocations
* don't do double copy_from_user()
* don't duplicate parts of check for audit_dummy_context()
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

* logging the original value of *msg_prio in mq_timedreceive(2)
  is insane - the argument is write-only (i.e. syscall always
  ignores the original value and only overwrites it).
* merge __audit_mq_timed{send,receive}
* don't do copy_from_user() twice
* don't mess with allocations in auditsc part
* ... and don't bother checking !audit_enabled and !context in there -
  we'd already checked for audit_dummy_context().
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

* don't copy_from_user() twice
* don't bother with allocations
* don't duplicate parts of audit_dummy_context()
* make it return void
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

* get rid of allocations
* make it return void
* don't duplicate parts of audit_dummy_context()
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Pass credentials through dentry_open() so that the COW creds patch can have
SELinux's flush_unauthorized_files() pass the appropriate creds back to itself
when it opens its null chardev.

The security_dentry_open() call also now takes a creds pointer, as does the
dentry_open hook in struct security_operations.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NJames Morris <jmorris@namei.org>
Signed-off-by: NJames Morris <jmorris@namei.org>

Wrap current->cred and a few other accessors to hide their actual
implementation.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NJames Morris <jmorris@namei.org>
Acked-by: NSerge Hallyn <serue@us.ibm.com>
Signed-off-by: NJames Morris <jmorris@namei.org>

Separate the task security context from task_struct.  At this point, the
security data is temporarily embedded in the task_struct with two pointers
pointing to it.

Note that the Alpha arch is altered as it refers to (E)UID and (E)GID in
entry.S via asm-offsets.

With comment fixes Signed-off-by: Marc Dionne <marc.c.dionne@gmail.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NJames Morris <jmorris@namei.org>
Acked-by: NSerge Hallyn <serue@us.ibm.com>
Signed-off-by: NJames Morris <jmorris@namei.org>

Wrap access to task credentials so that they can be separated more easily from
the task_struct during the introduction of COW creds.

Change most current->(|e|s|fs)[ug]id to current_(|e|s|fs)[ug]id().

Change some task->e?[ug]id to task_e?[ug]id().  In some places it makes more
sense to use RCU directly rather than a convenient wrapper; these will be
addressed by later patches.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Reviewed-by: NJames Morris <jmorris@namei.org>
Acked-by: NSerge Hallyn <serue@us.ibm.com>
Signed-off-by: NJames Morris <jmorris@namei.org>

Increase the range of various posix message queue limits.

Posix gives the message queue user the ability to 'trade off' the maximum
size of messages with the number of possible messages that can be 'in
flight'.  Linux currently makes this trade off more restrictive than it
needs to be.

In particular, the maximum message size today can be made no smaller than
8192.  This greatly restricts those applications that would like to have
the ability to post large numbers of very small messages.

So this task lowers the limit that the maximum message size can be set to,
from 8192 to 128.  It also lowers the limit that the maximum #number of
messages in flight can be set to, from 10 to 1.

With these changes the message queue user can make better trade offs
between #messages and message size, in order to get everything to fit
within the setrlimit(RLIMIT_MSGQUEUE) limit for that particular user.

This patch also applies the values in

	/proc/sys/fs/mqueue/msg_max
	/proc/sys/fs/mqueue/msgsize_max

as the defaults for the max #messages allowed and the max message size
allowed, respectively, for those applications that do not supply these.
Previously, the defaults were hardwired to 10 and 8192, respectively.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NJoe Korty <joe.korty@ccur.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Nadia Derbey <Nadia.Derbey@bull.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Incidentally, the name that gives hundreds of false positives on grep
is not a good idea...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Kmem cache passed to constructor is only needed for constructors that are
themselves multiplexeres.  Nobody uses this "feature", nor does anybody uses
passed kmem cache in non-trivial way, so pass only pointer to object.

Non-trivial places are:
	arch/powerpc/mm/init_64.c
	arch/powerpc/mm/hugetlbpage.c

This is flag day, yes.
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Acked-by: NPekka Enberg <penberg@cs.helsinki.fi>
Acked-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Jon Tollefson <kniht@linux.vnet.ibm.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Matt Mackall <mpm@selenic.com>
[akpm@linux-foundation.org: fix arch/powerpc/mm/hugetlbpage.c]
[akpm@linux-foundation.org: fix mm/slab.c]
[akpm@linux-foundation.org: fix ubifs]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Also this patch kills unneccesary trailing NULL character.
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Cc: Nadia Derbey <Nadia.Derbey@bull.net>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Pierre Peiffer <peifferp@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NDenis V. Lunev <den@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

A very small cleanup for mq_open.

We do not have to call set_close_on_exit if we create the file
descriptor right away with the flag set.  We have a function for this
now.  The resulting code is smaller and a tiny bit faster.
Signed-off-by: NUlrich Drepper <drepper@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This is the first really tricky patch in the series.  It elevates the writer
count on a mount each time a non-special file is opened for write.

We used to do this in may_open(), but Miklos pointed out that __dentry_open()
is used as well to create filps.  This will cover even those cases, while a
call in may_open() would not have.

There is also an elevated count around the vfs_create() call in open_namei().
See the comments for more details, but we need this to fix a 'create, remount,
fail r/w open()' race.

Some filesystems forego the use of normal vfs calls to create
struct files.   Make sure that these users elevate the mnt
writer count because they will get __fput(), and we need
to make sure they're balanced.
Acked-by: NAl Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDave Hansen <haveblue@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Elevate the write count during the vfs_rmdir() and vfs_unlink().

[AV: merged rmdir and unlink parts, added missing pieces in nfsd]
Acked-by: NSerge Hallyn <serue@us.ibm.com>
Acked-by: NAl Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDave Hansen <haveblue@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

When sending the pid namespaces patches I wrongly converted the tsk->tgid into
task_pid_vnr(tsk) in mqueue-s (the git id of this patch is
b488893a).

The proper behavior is to get the task_tgid_vnr(tsk).

This seem to be the only mistake of that kind.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Some time ago the xxx_vnr() calls (e.g.  pid_vnr or find_task_by_vpid) were
_all_ converted to operate on the current pid namespace.  After this each call
like xxx_nr_ns(foo, current->nsproxy->pid_ns) is nothing but a xxx_vnr(foo)
one.

Switch all the xxx_nr_ns() callers to use the xxx_vnr() calls where
appropriate.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Reviewed-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The error path in sys_mq_getsetattr() after the call to
audit_mq_getsetattr() is wrong - the info->lock is not unlocked and the
struct file *filp is not put.

Fix them both.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Cc: Pierre Peiffer <pierre.peiffer@bull.net>
Cc: Nadia Derbey <Nadia.Derbey@bull.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit ed6dcf4a in the history.git tree broke netlink_unicast timeouts
by moving the schedule_timeout() call to a new function that doesn't
propagate the remaining timeout back to the caller. This means on each
retry we start with the full timeout again.

ipc/mqueue.c seems to actually want to wait indefinitely so this
behaviour is retained.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>