selinux: Fix Kernel panic due to NULL pointer dereference

Below Kernel panic is observed due to race condition, where
sock_has_perm called in a thread and is trying to access sksec->sid
without checking sksec. Just before that, sk->sk_security was set
to NULL by selinux_sk_free_security through sk_free in other thread.

31704.949269:   <3> IPv4: Attempt to release alive inet socket dd81b200
31704.959049:   <1> Unable to handle kernel NULL pointer dereference at \
                        virtual address 00000000
31704.983562:   <1> pgd = c6b74000
31704.985248:   <1> [00000000] *pgd=00000000
31704.996591:   <0> Internal error: Oops: 5 [#1] PREEMPT SMP ARM
31705.001016:   <6> Modules linked in: adsprpc [last unloaded: wlan]
31705.006659:   <6> CPU: 1    Tainted: G           O  \
                        (3.4.0-g837ab9b-00003-g6bcd9c6 #1)
31705.014042:   <6> PC is at sock_has_perm+0x58/0xd4
31705.018292:   <6> LR is at sock_has_perm+0x58/0xd4
31705.022546:   <6> pc : [<c0341e8c>]    lr : [<c0341e8c>]    \
                                                  psr: 60000013
31705.022549:   <6> sp : dda27f00  ip : 00000000  fp : 5f36fc84
31705.034002:   <6> r10: 00004000  r9 : 0000009d  r8 : e8c2b700
31705.039211:   <6> r7 : dda27f24  r6 : dd81b200  r5 : 00000000  \
                                                  r4 : 00000000
31705.045721:   <6> r3 : 00000000  r2 : dda27ef8  r1 : 00000000  \
                                                  r0 : dda27f54
31705.052232:   <6> Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM \
                        Segment user
31705.059349:   <6> Control: 10c5787d  Table: 10d7406a  DAC: 00000015
.
.
.
.
31705.697816:   <6> [<c0341e8c>] (sock_has_perm+0x58/0xd4) from \
                    [<c033ed10>] (security_socket_getsockopt+0x14/0x1c)
31705.707534:   <6> [<c033ed10>] (security_socket_getsockopt+0x14/0x1c) \
                           from [<c0745c18>] (sys_getsockopt+0x34/0xa8)
31705.717343:   <6> [<c0745c18>] (sys_getsockopt+0x34/0xa8) from \
                    [<c0106140>] (ret_fast_syscall+0x0/0x30)
31705.726193:   <0> Code: e59832e8 e5933058 e5939004 ebfac736 (e5953000)
31705.732635:   <4> ---[ end trace 22889004dafd87bd ]---

Change-Id: I79c3fb525f35ea2494d53788788cd71a38a32d6b
Signed-off-by: Satya Durga Srinivasu Prabhala <satyap@codeaurora.org>
Signed-off-by: Osvaldo Banuelos <osvaldob@codeaurora.org>
ipv4: Dump stack on attempt to release alive inet socket

In commit 82e1cecf1 we hide a bug, that will make SELinux
bomb out. Let's dump the stack when it happens to have at
least a chance to find the cause.

Change-Id: I7f9b864d76a48b150c5f248417b47751424449bd
SELinux: Fix possible NULL pointer dereference in selinux_inode_permission()

While running stress tests on adding and deleting ftrace instances I hit
this bug:

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000020
  IP: selinux_inode_permission+0x85/0x160
  PGD 63681067 PUD 7ddbe067 PMD 0
  Oops: 0000 [#1] PREEMPT
  CPU: 0 PID: 5634 Comm: ftrace-test-mki Not tainted 3.13.0-rc4-test-00033-gd2a6dde-dirty #20
  Hardware name:                  /DG965MQ, BIOS MQ96510J.86A.0372.2006.0605.1717 06/05/2006
  task: ffff880078375800 ti: ffff88007ddb0000 task.ti: ffff88007ddb0000
  RIP: 0010:[<ffffffff812d8bc5>]  [<ffffffff812d8bc5>] selinux_inode_permission+0x85/0x160
  RSP: 0018:ffff88007ddb1c48  EFLAGS: 00010246
  RAX: 0000000000000000 RBX: 0000000000800000 RCX: ffff88006dd43840
  RDX: 0000000000000001 RSI: 0000000000000081 RDI: ffff88006ee46000
  RBP: ffff88007ddb1c88 R08: 0000000000000000 R09: ffff88007ddb1c54
  R10: 6e6576652f6f6f66 R11: 0000000000000003 R12: 0000000000000000
  R13: 0000000000000081 R14: ffff88006ee46000 R15: 0000000000000000
  FS:  00007f217b5b6700(0000) GS:ffffffff81e21000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033^M
  CR2: 0000000000000020 CR3: 000000006a0fe000 CR4: 00000000000007f0
  Call Trace:
    security_inode_permission+0x1c/0x30
    __inode_permission+0x41/0xa0
    inode_permission+0x18/0x50
    link_path_walk+0x66/0x920
    path_openat+0xa6/0x6c0
    do_filp_open+0x43/0xa0
    do_sys_open+0x146/0x240
    SyS_open+0x1e/0x20
    system_call_fastpath+0x16/0x1b
  Code: 84 a1 00 00 00 81 e3 00 20 00 00 89 d8 83 c8 02 40 f6 c6 04 0f 45 d8 40 f6 c6 08 74 71 80 cf 02 49 8b 46 38 4c 8d 4d cc 45 31 c0 <0f> b7 50 20 8b 70 1c 48 8b 41 70 89 d9 8b 78 04 e8 36 cf ff ff
  RIP  selinux_inode_permission+0x85/0x160
  CR2: 0000000000000020

Investigating, I found that the inode->i_security was NULL, and the
dereference of it caused the oops.

in selinux_inode_permission():

	isec = inode->i_security;

	rc = avc_has_perm_noaudit(sid, isec->sid, isec->sclass, perms, 0, &avd);

Note, the crash came from stressing the deletion and reading of debugfs
files.  I was not able to recreate this via normal files.  But I'm not
sure they are safe.  It may just be that the race window is much harder
to hit.

What seems to have happened (and what I have traced), is the file is
being opened at the same time the file or directory is being deleted.
As the dentry and inode locks are not held during the path walk, nor is
the inodes ref counts being incremented, there is nothing saving these
structures from being discarded except for an rcu_read_lock().

The rcu_read_lock() protects against freeing of the inode, but it does
not protect freeing of the inode_security_struct.  Now if the freeing of
the i_security happens with a call_rcu(), and the i_security field of
the inode is not changed (it gets freed as the inode gets freed) then
there will be no issue here.  (Linus Torvalds suggested not setting the
field to NULL such that we do not need to check if it is NULL in the
permission check).

Note, this is a hack, but it fixes the problem at hand.  A real fix is
to restructure the destroy_inode() to call all the destructor handlers
from the RCU callback.  But that is a major job to do, and requires a
lot of work.  For now, we just band-aid this bug with this fix (it
works), and work on a more maintainable solution in the future.

Link: http://lkml.kernel.org/r/20140109101932.0508dec7@gandalf.local.home
Link: http://lkml.kernel.org/r/20140109182756.17abaaa8@gandalf.local.home

Cc: stable@vger.kernel.org
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Change-Id: Iab1d8871f1dffa499e10ba9d845ac204d0fee32a
SELinux: Fix memory leak upon loading policy

commit 8ed814602876bec9bad2649ca17f34b499357a1c upstream.

Hello.

I got below leak with linux-3.10.0-54.0.1.el7.x86_64 .

[  681.903890] kmemleak: 5538 new suspected memory leaks (see /sys/kernel/debug/kmemleak)

Below is a patch, but I don't know whether we need special handing for undoing
ebitmap_set_bit() call.
----------
>>From fe97527a90fe95e2239dfbaa7558f0ed559c0992 Mon Sep 17 00:00:00 2001
From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Date: Mon, 6 Jan 2014 16:30:21 +0900
Subject: SELinux: Fix memory leak upon loading policy

Commit 2463c26d "SELinux: put name based create rules in a hashtable" did not
check return value from hashtab_insert() in filename_trans_read(). It leaks
memory if hashtab_insert() returns error.

  unreferenced object 0xffff88005c9160d0 (size 8):
    comm "systemd", pid 1, jiffies 4294688674 (age 235.265s)
    hex dump (first 8 bytes):
      57 0b 00 00 6b 6b 6b a5                          W...kkk.
    backtrace:
      [<ffffffff816604ae>] kmemleak_alloc+0x4e/0xb0
      [<ffffffff811cba5e>] kmem_cache_alloc_trace+0x12e/0x360
      [<ffffffff812aec5d>] policydb_read+0xd1d/0xf70
      [<ffffffff812b345c>] security_load_policy+0x6c/0x500
      [<ffffffff812a623c>] sel_write_load+0xac/0x750
      [<ffffffff811eb680>] vfs_write+0xc0/0x1f0
      [<ffffffff811ec08c>] SyS_write+0x4c/0xa0
      [<ffffffff81690419>] system_call_fastpath+0x16/0x1b
      [<ffffffffffffffff>] 0xffffffffffffffff

However, we should not return EEXIST error to the caller, or the systemd will
show below message and the boot sequence freezes.

  systemd[1]: Failed to load SELinux policy. Freezing.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Paul Moore <pmoore@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Change-Id: I5204ed79917dc5d0a4a5e7be7dff7a0035ac09b9
cpufreq: ondemand: Remove unnecessary synchronization attempt

Commit 1ce28d6b (ondemand: updated tune for hardware coordination)
brings in an attempt to synchronize expiry of per-cpu ondemand timer
at same time across all online cpus. This is meant to help systems
where "multiple cores share P-state via Hardware Coordination".

Synchronization is achieved by having timers expire when jiffy value
would be a perfect multiple of sampling window size. While such
synchronozation attemps are unnecessary on systems where cores don't
share P-states, it can hurt on power as cpus can now work off shorter
sampling windows (when percentage utilization over short window can be
observed to be high, causing frequency to be boosted).

Remove this unnecessary attempt to synchronize expiry of ondemand
timer across online cpus. A more acceptable solution could be to have
low-level architecture specific cpufreq driver indicate the need for
synchronization.

Change-Id: I6cb1cf3472ca106f029dc01248e0df7cfbb495b8
Signed-off-by: Srivatsa Vaddagiri <vatsa@codeaurora.org>
cpufreq: interactive: delete timers for GOV_START

Make sure that timers cpu_timer and cpu_slack_timer
deactivated before addition of new.

Change-Id: If31c4049606871df6f00efdc24b1d713c86a6f69
Signed-off-by: Shridhar Rasal <srasal@nvidia.com>
Signed-off-by: Bharat Nihalani <bnihalani@nvidia.com>
Git-commit: b430123367e78a6557bac3cf1558bcb85193fb12
Git-repo: https://android.googlesource.com/kernel/common/
[mattw@codeaurora.org: resolved trivial context conflict]
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>
staging: android: ashmem: Avoid deadlock with mmap/shrink

Both ashmem_mmap and ashmem_shrink take the ashmem_lock. It may
be possible for ashmem_mmap to invoke ashmem_shrink:

-000|mutex_lock(lock = 0x0)
-001|ashmem_shrink(?, sc = 0x0) <--- try to take ashmem_mutex again
-002|shrink_slab(shrink = 0xDA5F1CC0, nr_pages_scanned = 0, lru_pages
-002|=
-002|124)
-003|try_to_free_pages(zonelist = 0x0, ?, ?, ?)
-004|__alloc_pages_nodemask(gfp_mask = 21200, order = 1, zonelist =
-004|0xC11D0940,
-005|new_slab(s = 0xE4841E80, ?, node = -1)
-006|__slab_alloc.isra.43.constprop.50(s = 0xE4841E80, gfpflags =
-006|2148925462, ad
-007|kmem_cache_alloc(s = 0xE4841E80, gfpflags = 208)
-008|shmem_alloc_inode(?)
-009|alloc_inode(sb = 0xE480E800)
-010|new_inode_pseudo(?)
-011|new_inode(?)
-012|shmem_get_inode(sb = 0xE480E800, dir = 0x0, ?, dev = 0, flags =
-012|187)
-013|shmem_file_setup(?, ?, flags = 187)
-014|ashmem_mmap(?, vma = 0xC5D64210) <---- Acquire ashmem_mutex
-015|mmap_region(file = 0xDF8E2C00, addr = 1772974080, len = 233472,
-015|flags = 57,
-016|sys_mmap_pgoff(addr = 0, len = 230400, prot = 3, flags = 1, fd =
-016|157, pgoff
-017|ret_fast_syscall(asm)
-->|exception
-018|NUR:0x40097508(asm)
---|end of frame

Avoid this deadlock by using mutex_trylock in ashmem_shrink; if the mutex
is already held, do not attempt to shrink.

Change-Id: I222bbf55856d5849da813b730de0636c80966c8e
CRs-Fixed: 608832
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
cma: Remove potential deadlock situation

A report was given of a deadlock situation on the cma_mutex:

mutex_lock(cma_mutex)   (*2)
dma_release_from_contiguous
ion_secure_cma_free_chunk
ion_secure_cma_shrinker
shrink_slab
try_to_free_pages
migrate_pages
alloc_contig_range
mutex_lock(cma_mutex)  (*1)
dma_alloc_from_contiguous
ion_alloc

We may need to free CMA allocations while a current CMA allocation is in
progress if CMA is freed from a shrinker. cma_mutex currently protects
two things: the bitmap indicating which pages are allocated/free and
serialization of isolation/migration calls on allocation. There is
no need to take the mutex on free calls though as the pages are
freed back into the system via the regular __free_page call. Move
the free_contig_range call outside the cma_mutex to break the
chain dependency. We can safely free the pages back into the system
before changing the bitmap without any risk of races.

Change-Id: I4989eb2891e502b08db8117a51bd86652e902778
CRs-Fixed: 619644
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>