08 Apr, 2014

1 commit


28 Jan, 2014

7 commits

  • This field is only used to reset the ids seq number if it exceeds the
    smaller of INT_MAX/SEQ_MULTIPLIER and USHRT_MAX, and can therefore be
    moved out of the structure and into its own macro. Since each
    ipc_namespace contains a table of 3 pointers to struct ipc_ids we can
    save space in instruction text:

    text data bss dec hex filename
    56232 2348 24 58604 e4ec ipc/built-in.o
    56216 2348 24 58588 e4dc ipc/built-in.o-after

    Signed-off-by: Davidlohr Bueso
    Reviewed-by: Jonathan Gonzalez
    Cc: Aswin Chandramouleeswaran
    Cc: Rik van Riel
    Acked-by: Manfred Spraul
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Davidlohr Bueso
     
  • Get rid of silly/useless label jumping.

    Signed-off-by: Davidlohr Bueso
    Cc: Aswin Chandramouleeswaran
    Cc: Rik van Riel
    Acked-by: Manfred Spraul
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Davidlohr Bueso
     
  • Only found in ipc_rmid().

    Signed-off-by: Davidlohr Bueso
    Cc: Aswin Chandramouleeswaran
    Cc: Rik van Riel
    Acked-by: Manfred Spraul
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Davidlohr Bueso
     
  • Deal with checkpatch messages:
    WARNING: braces {} are not necessary for single statement blocks

    Signed-off-by: Davidlohr Bueso
    Cc: Aswin Chandramouleeswaran
    Cc: Rik van Riel
    Acked-by: Manfred Spraul
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Davidlohr Bueso
     
  • IPC commenting style is all over the place, *specially* in util.c. This
    patch orders things a bit.

    Signed-off-by: Davidlohr Bueso
    Cc: Aswin Chandramouleeswaran
    Cc: Rik van Riel
    Acked-by: Manfred Spraul
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Davidlohr Bueso
     
  • The ipc code does not adhere the typical linux coding style.
    This patch fixes lots of simple whitespace errors.

    - mostly autogenerated by
    scripts/checkpatch.pl -f --fix \
    --types=pointer_location,spacing,space_before_tab
    - one manual fixup (keep structure members tab-aligned)
    - removal of additional space_before_tab that were not found by --fix

    Tested with some of my msg and sem test apps.

    Andrew: Could you include it in -mm and move it towards Linus' tree?

    Signed-off-by: Manfred Spraul
    Suggested-by: Li Bin
    Cc: Joe Perches
    Acked-by: Rafael Aquini
    Cc: Davidlohr Bueso
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Manfred Spraul
     
  • struct kern_ipc_perm.deleted is meant to be used as a boolean toggle, and
    the changes introduced by this patch are just to make the case explicit.

    Signed-off-by: Rafael Aquini
    Reviewed-by: Rik van Riel
    Cc: Greg Thelen
    Acked-by: Davidlohr Bueso
    Cc: Manfred Spraul
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Rafael Aquini
     

13 Nov, 2013

1 commit


17 Oct, 2013

1 commit

  • The initial documentation was a bit incomplete, update accordingly.

    [akpm@linux-foundation.org: make it more readable in 80 columns]
    Signed-off-by: Davidlohr Bueso
    Acked-by: Manfred Spraul
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Davidlohr Bueso
     

25 Sep, 2013

1 commit

  • Currently, IPC mechanisms do security and auditing related checks under
    RCU. However, since security modules can free the security structure,
    for example, through selinux_[sem,msg_queue,shm]_free_security(), we can
    race if the structure is freed before other tasks are done with it,
    creating a use-after-free condition. Manfred illustrates this nicely,
    for instance with shared mem and selinux:

    -> do_shmat calls rcu_read_lock()
    -> do_shmat calls shm_object_check().
    Checks that the object is still valid - but doesn't acquire any locks.
    Then it returns.
    -> do_shmat calls security_shm_shmat (e.g. selinux_shm_shmat)
    -> selinux_shm_shmat calls ipc_has_perm()
    -> ipc_has_perm accesses ipc_perms->security

    shm_close()
    -> shm_close acquires rw_mutex & shm_lock
    -> shm_close calls shm_destroy
    -> shm_destroy calls security_shm_free (e.g. selinux_shm_free_security)
    -> selinux_shm_free_security calls ipc_free_security(&shp->shm_perm)
    -> ipc_free_security calls kfree(ipc_perms->security)

    This patch delays the freeing of the security structures after all RCU
    readers are done. Furthermore it aligns the security life cycle with
    that of the rest of IPC - freeing them based on the reference counter.
    For situations where we need not free security, the current behavior is
    kept. Linus states:

    "... the old behavior was suspect for another reason too: having the
    security blob go away from under a user sounds like it could cause
    various other problems anyway, so I think the old code was at least
    _prone_ to bugs even if it didn't have catastrophic behavior."

    I have tested this patch with IPC testcases from LTP on both my
    quad-core laptop and on a 64 core NUMA server. In both cases selinux is
    enabled, and tests pass for both voluntary and forced preemption models.
    While the mentioned races are theoretical (at least no one as reported
    them), I wanted to make sure that this new logic doesn't break anything
    we weren't aware of.

    Suggested-by: Linus Torvalds
    Signed-off-by: Davidlohr Bueso
    Acked-by: Manfred Spraul
    Signed-off-by: Linus Torvalds

    Davidlohr Bueso
     

12 Sep, 2013

5 commits

  • No remaining users, we now use ipc_obtain_object_check().

    Signed-off-by: Davidlohr Bueso
    Cc: Sedat Dilek
    Cc: Rik van Riel
    Cc: Manfred Spraul
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Davidlohr Bueso
     
  • After previous cleanups and optimizations, this function is no longer
    heavily used and we don't have a good reason to keep it. Update the few
    remaining callers and get rid of it.

    Signed-off-by: Davidlohr Bueso
    Cc: Sedat Dilek
    Cc: Rik van Riel
    Cc: Manfred Spraul
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Davidlohr Bueso
     
  • As suggested by Andrew, add a generic initial locking scheme used
    throughout all sysv ipc mechanisms. Documenting the ids rwsem, how rcu
    can be enough to do the initial checks and when to actually acquire the
    kern_ipc_perm.lock spinlock.

    I found that adding it to util.c was generic enough.

    Signed-off-by: Davidlohr Bueso
    Tested-by: Sedat Dilek
    Cc: Rik van Riel
    Cc: Manfred Spraul
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Davidlohr Bueso
     
  • Since in some situations the lock can be shared for readers, we shouldn't
    be calling it a mutex, rename it to rwsem.

    Signed-off-by: Davidlohr Bueso
    Tested-by: Sedat Dilek
    Cc: Rik van Riel
    Cc: Manfred Spraul
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Davidlohr Bueso
     
  • Now that sem, msgque and shm, through *_down(), all use the lockless
    variant of ipcctl_pre_down(), go ahead and delete it.

    [akpm@linux-foundation.org: fix function name in kerneldoc, cleanups]
    Signed-off-by: Davidlohr Bueso
    Tested-by: Sedat Dilek
    Cc: Rik van Riel
    Cc: Manfred Spraul
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Davidlohr Bueso
     

10 Jul, 2013

3 commits

  • Enforce that ipc_rcu_alloc returns a cacheline aligned pointer on SMP.

    Rationale:

    The SysV sem code tries to move the main spinlock into a seperate
    cacheline (____cacheline_aligned_in_smp). This works only if
    ipc_rcu_alloc returns cacheline aligned pointers. vmalloc and kmalloc
    return cacheline algined pointers, the implementation of ipc_rcu_alloc
    breaks that.

    [akpm@linux-foundation.org: coding-style fixes]
    Signed-off-by: Manfred Spraul
    Cc: Rik van Riel
    Cc: Davidlohr Bueso
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Manfred Spraul
     
  • This function currently acquires both the rw_mutex and the rcu lock on
    successful lookups, leaving the callers to explicitly unlock them,
    creating another two level locking situation.

    Make the callers (including those that still use ipcctl_pre_down())
    explicitly lock and unlock the rwsem and rcu lock.

    Signed-off-by: Davidlohr Bueso
    Cc: Andi Kleen
    Cc: Rik van Riel
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Davidlohr Bueso
     
  • This patchset continues the work that began in the sysv ipc semaphore
    scaling series, see

    https://lkml.org/lkml/2013/3/20/546

    Just like semaphores used to be, sysv shared memory and msg queues also
    abuse the ipc lock, unnecessarily holding it for operations such as
    permission and security checks.

    This patchset mostly deals with mqueues, and while shared mem can be
    done in a very similar way, I want to get these patches out in the open
    first. It also does some pending cleanups, mostly focused on the two
    level locking we have in ipc code, taking care of ipc_addid() and
    ipcctl_pre_down_nolock() - yes there are still functions that need to be
    updated as well.

    This patch:

    Make all callers explicitly take and release the RCU read lock.

    This addresses the two level locking seen in newary(), newseg() and
    newqueue(). For the last two, explicitly unlock the ipc object and the
    rcu lock, instead of calling the custom shm_unlock and msg_unlock
    functions. The next patch will deal with the open coded locking for
    ->perm.lock

    Signed-off-by: Davidlohr Bueso
    Cc: Andi Kleen
    Cc: Rik van Riel
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Davidlohr Bueso
     

02 May, 2013

2 commits

  • Commit 32fcfd40715e ("make vfree() safe to call from interrupt
    contexts") made it safe to do vfree directly from the RCU callback,
    which allows us to simplify ipc/util.c a lot by getting rid of the
    differences between vmalloc/kmalloc memory.

    Signed-off-by: Al Viro
    Signed-off-by: Linus Torvalds

    Al Viro
     
  • Pull VFS updates from Al Viro,

    Misc cleanups all over the place, mainly wrt /proc interfaces (switch
    create_proc_entry to proc_create(), get rid of the deprecated
    create_proc_read_entry() in favor of using proc_create_data() and
    seq_file etc).

    7kloc removed.

    * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (204 commits)
    don't bother with deferred freeing of fdtables
    proc: Move non-public stuff from linux/proc_fs.h to fs/proc/internal.h
    proc: Make the PROC_I() and PDE() macros internal to procfs
    proc: Supply a function to remove a proc entry by PDE
    take cgroup_open() and cpuset_open() to fs/proc/base.c
    ppc: Clean up scanlog
    ppc: Clean up rtas_flash driver somewhat
    hostap: proc: Use remove_proc_subtree()
    drm: proc: Use remove_proc_subtree()
    drm: proc: Use minor->index to label things, not PDE->name
    drm: Constify drm_proc_list[]
    zoran: Don't print proc_dir_entry data in debug
    reiserfs: Don't access the proc_dir_entry in r_open(), r_start() r_show()
    proc: Supply an accessor for getting the data from a PDE's parent
    airo: Use remove_proc_subtree()
    rtl8192u: Don't need to save device proc dir PDE
    rtl8187se: Use a dir under /proc/net/r8180/
    proc: Add proc_mkdir_data()
    proc: Move some bits from linux/proc_fs.h to linux/{of.h,signal.h,tty.h}
    proc: Move PDE_NET() to fs/proc/proc_net.c
    ...

    Linus Torvalds
     

01 May, 2013

3 commits

  • Introduce finer grained locking for semtimedop, to handle the common case
    of a program wanting to manipulate one semaphore from an array with
    multiple semaphores.

    If the call is a semop manipulating just one semaphore in an array with
    multiple semaphores, only take the lock for that semaphore itself.

    If the call needs to manipulate multiple semaphores, or another caller is
    in a transaction that manipulates multiple semaphores, the sem_array lock
    is taken, as well as all the locks for the individual semaphores.

    On a 24 CPU system, performance numbers with the semop-multi
    test with N threads and N semaphores, look like this:

    vanilla Davidlohr's Davidlohr's + Davidlohr's +
    threads patches rwlock patches v3 patches
    10 610652 726325 1783589 2142206
    20 341570 365699 1520453 1977878
    30 288102 307037 1498167 2037995
    40 290714 305955 1612665 2256484
    50 288620 312890 1733453 2650292
    60 289987 306043 1649360 2388008
    70 291298 306347 1723167 2717486
    80 290948 305662 1729545 2763582
    90 290996 306680 1736021 2757524
    100 292243 306700 1773700 3059159

    [davidlohr.bueso@hp.com: do not call sem_lock when bogus sma]
    [davidlohr.bueso@hp.com: make refcounter atomic]
    Signed-off-by: Rik van Riel
    Suggested-by: Linus Torvalds
    Acked-by: Davidlohr Bueso
    Cc: Chegu Vinod
    Cc: Jason Low
    Reviewed-by: Michel Lespinasse
    Cc: Peter Hurley
    Cc: Stanislav Kinsbursky
    Tested-by: Emmanuel Benisty
    Tested-by: Sedat Dilek
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Rik van Riel
     
  • Various forms of ipc use ipcctl_pre_down() to retrieve an ipc object and
    check permissions, mostly for IPC_RMID and IPC_SET commands.

    Introduce ipcctl_pre_down_nolock(), a lockless version of this function.
    The locking version is retained, yet modified to call the nolock version
    without affecting its semantics, thus transparent to all ipc callers.

    Signed-off-by: Davidlohr Bueso
    Signed-off-by: Rik van Riel
    Suggested-by: Linus Torvalds
    Cc: Chegu Vinod
    Cc: Emmanuel Benisty
    Cc: Jason Low
    Cc: Michel Lespinasse
    Cc: Peter Hurley
    Cc: Stanislav Kinsbursky
    Tested-by: Sedat Dilek
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Davidlohr Bueso
     
  • Through ipc_lock() and therefore ipc_lock_check() we currently return the
    locked ipc object. This is not necessary for all situations and can,
    therefore, cause unnecessary ipc lock contention.

    Introduce analogous ipc_obtain_object() and ipc_obtain_object_check()
    functions that only lookup and return the ipc object.

    Both these functions must be called within the RCU read critical section.

    [akpm@linux-foundation.org: propagate the ipc_obtain_object() errno from ipc_lock()]
    Signed-off-by: Davidlohr Bueso
    Signed-off-by: Rik van Riel
    Reviewed-by: Chegu Vinod
    Acked-by: Michel Lespinasse
    Cc: Emmanuel Benisty
    Cc: Jason Low
    Cc: Peter Hurley
    Cc: Stanislav Kinsbursky
    Tested-by: Sedat Dilek
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Davidlohr Bueso
     

30 Apr, 2013

1 commit


10 Apr, 2013

1 commit

  • The only part of proc_dir_entry the code outside of fs/proc
    really cares about is PDE(inode)->data. Provide a helper
    for that; static inline for now, eventually will be moved
    to fs/proc, along with the knowledge of struct proc_dir_entry
    layout.

    Signed-off-by: Al Viro

    Al Viro
     

28 Feb, 2013

1 commit

  • Convert to the much saner new idr interface.

    The new interface doesn't directly translate to the way idr_pre_get()
    was used around ipc_addid() as preloading disables preemption. From
    my cursory reading, it seems like we should be able to do all
    allocation from ipc_addid(), so I moved it there. Can you please
    check whether this would be okay? If this is wrong and ipc_addid()
    should be allowed to be called from non-sleepable context, I'd suggest
    allocating id itself in the outer functions and later install the
    pointer using idr_replace().

    Signed-off-by: Tejun Heo
    Reported-by: Sedat Dilek
    Tested-by: Sedat Dilek
    Cc: Stanislav Kinsbursky
    Cc: "Eric W. Biederman"
    Cc: James Morris
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Tejun Heo
     

05 Jan, 2013

1 commit

  • Add 3 new variables and sysctls to tune them (by one "next_id" variable
    for messages, semaphores and shared memory respectively). This variable
    can be used to set desired id for next allocated IPC object. By default
    it's equal to -1 and old behaviour is preserved. If this variable is
    non-negative, then desired idr will be extracted from it and used as a
    start value to search for free IDR slot.

    Notes:

    1) this patch doesn't guarantee that the new object will have desired
    id. So it's up to user space how to handle new object with wrong id.

    2) After a sucessful id allocation attempt, "next_id" will be set back
    to -1 (if it was non-negative).

    [akpm@linux-foundation.org: checkpatch fixes]
    Signed-off-by: Stanislav Kinsbursky
    Cc: Serge Hallyn
    Cc: "Eric W. Biederman"
    Cc: Pavel Emelyanov
    Cc: Al Viro
    Cc: KOSAKI Motohiro
    Cc: Michael Kerrisk
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Stanislav Kinsbursky
     

07 Sep, 2012

1 commit

  • - Store the ipc owner and creator with a kuid
    - Store the ipc group and the crators group with a kgid.
    - Add error handling to ipc_update_perms, allowing it to
    fail if the uids and gids can not be converted to kuids
    or kgids.
    - Modify the proc files to display the ipc creator and
    owner in the user namespace of the opener of the proc file.

    Signed-off-by: Eric W. Biederman

    Eric W. Biederman
     

31 Jul, 2012

1 commit

  • Rather than #define the options manually in the architecture code, add
    Kconfig options for them and select them there instead. This also allows
    us to select the compat IPC version parsing automatically for platforms
    using the old compat IPC interface.

    Reported-by: Andrew Morton
    Signed-off-by: Will Deacon
    Cc: Arnd Bergmann
    Cc: Chris Metcalf
    Cc: Catalin Marinas
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Will Deacon
     

21 Jul, 2011

1 commit


28 Mar, 2011

1 commit

  • Fix ipc/util.c kernel-doc warnings:

    Warning(ipc/util.c:336): No description found for parameter 'ns'
    Warning(ipc/util.c:620): No description found for parameter 'ns'
    Warning(ipc/util.c:790): No description found for parameter 'ns'

    Signed-off-by: Randy Dunlap
    Reviewed-by: Jesper Juhl
    Signed-off-by: Linus Torvalds

    Randy Dunlap
     

24 Mar, 2011

1 commit

  • CAP_IPC_OWNER and CAP_IPC_LOCK can be checked against current_user_ns(),
    because the resource comes from current's own ipc namespace.

    setuid/setgid are to uids in own namespace, so again checks can be against
    current_user_ns().

    Changelog:
    Jan 11: Use task_ns_capable() in place of sched_capable().
    Jan 11: Use nsown_capable() as suggested by Bastian Blank.
    Jan 11: Clarify (hopefully) some logic in futex and sched.c
    Feb 15: use ns_capable for ipc, not nsown_capable
    Feb 23: let copy_ipcs handle setting ipc_ns->user_ns
    Feb 23: pass ns down rather than taking it from current

    [akpm@linux-foundation.org: coding-style fixes]
    Signed-off-by: Serge E. Hallyn
    Acked-by: "Eric W. Biederman"
    Acked-by: Daniel Lezcano
    Acked-by: David Howells
    Cc: James Morris
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Serge E. Hallyn
     

25 May, 2010

1 commit


23 Sep, 2009

1 commit

  • Make all seq_operations structs const, to help mitigate against
    revectoring user-triggerable function pointers.

    This is derived from the grsecurity patch, although generated from scratch
    because it's simpler than extracting the changes from there.

    Signed-off-by: James Morris
    Acked-by: Serge Hallyn
    Acked-by: Casey Schaufler
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    James Morris
     

07 Apr, 2009

1 commit

  • 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: Cedric Le Goater
    Signed-off-by: Serge E. Hallyn
    Cc: Alexey Dobriyan
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Serge E. Hallyn
     

05 Jan, 2009

2 commits


04 Dec, 2008

1 commit


20 Nov, 2008

1 commit

  • A problem was found while reviewing the code after Bugzilla bug
    http://bugzilla.kernel.org/show_bug.cgi?id=11796.

    In ipc_addid(), the newly allocated ipc structure is inserted into the
    ipcs tree (i.e made visible to readers) without locking it. This is not
    correct since its initialization continues after it has been inserted in
    the tree.

    This patch moves the ipc structure lock initialization + locking before
    the actual insertion.

    Signed-off-by: Nadia Derbey
    Reported-by: Clement Calmels
    Cc: Manfred Spraul
    Cc: [2.6.27.x]
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Nadia Derbey