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  1. 28 1月, 2014 7 次提交
  3. 13 11月, 2013 1 次提交
  5. 17 10月, 2013 1 次提交
  7. 25 9月, 2013 1 次提交
    • D
      ipc: fix race with LSMs · 53dad6d3
      由 Davidlohr Bueso 提交于 
      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: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NDavidlohr Bueso <davidlohr@hp.com>
Acked-by: NManfred Spraul <manfred@colorfullife.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      53dad6d3
  9. 12 9月, 2013 5 次提交
  11. 10 7月, 2013 3 次提交
  13. 02 5月, 2013 1 次提交
  15. 01 5月, 2013 3 次提交
  17. 30 4月, 2013 1 次提交
  19. 10 4月, 2013 1 次提交
    • A
      procfs: new helper - PDE_DATA(inode) · d9dda78b
      由 Al Viro 提交于 
      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: NAl Viro <viro@zeniv.linux.org.uk>
      d9dda78b
  21. 28 2月, 2013 1 次提交
  23. 05 1月, 2013 1 次提交
    • S
      ipc: add sysctl to specify desired next object id · 03f59566
      由 Stanislav Kinsbursky 提交于 
      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: NStanislav Kinsbursky <skinsbursky@parallels.com>
Cc: Serge Hallyn <serge.hallyn@canonical.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      03f59566
  25. 07 9月, 2012 1 次提交
  27. 31 7月, 2012 1 次提交
  29. 21 7月, 2011 1 次提交
  31. 28 3月, 2011 1 次提交
  33. 24 3月, 2011 1 次提交
  35. 25 5月, 2010 1 次提交
  37. 23 9月, 2009 1 次提交
  39. 07 4月, 2009 1 次提交
  41. 05 1月, 2009 2 次提交
  43. 20 11月, 2008 1 次提交
  45. 14 11月, 2008 1 次提交
  47. 26 7月, 2008 2 次提交