crypto: algboss - Hold ref count on larval

On Thu, Jun 20, 2013 at 10:00:21AM +0200, Daniel Borkmann wrote:
> After having fixed a NULL pointer dereference in SCTP 1abd165e ("net:
> sctp: fix NULL pointer dereference in socket destruction"), I ran into
> the following NULL pointer dereference in the crypto subsystem with
> the same reproducer, easily hit each time:
> 
> BUG: unable to handle kernel NULL pointer dereference at (null)
> IP: [<ffffffff81070321>] __wake_up_common+0x31/0x90
> PGD 0
> Oops: 0000 [#1] SMP
> Modules linked in: padlock_sha(F-) sha256_generic(F) sctp(F) libcrc32c(F) [..]
> CPU: 6 PID: 3326 Comm: cryptomgr_probe Tainted: GF            3.10.0-rc5+ #1
> Hardware name: Dell Inc. PowerEdge T410/0H19HD, BIOS 1.6.3 02/01/2011
> task: ffff88007b6cf4e0 ti: ffff88007b7cc000 task.ti: ffff88007b7cc000
> RIP: 0010:[<ffffffff81070321>]  [<ffffffff81070321>] __wake_up_common+0x31/0x90
> RSP: 0018:ffff88007b7cde08  EFLAGS: 00010082
> RAX: ffffffffffffffe8 RBX: ffff88003756c130 RCX: 0000000000000000
> RDX: 0000000000000000 RSI: 0000000000000003 RDI: ffff88003756c130
> RBP: ffff88007b7cde48 R08: 0000000000000000 R09: ffff88012b173200
> R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000282
> R13: ffff88003756c138 R14: 0000000000000000 R15: 0000000000000000
> FS:  0000000000000000(0000) GS:ffff88012fc60000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
> CR2: 0000000000000000 CR3: 0000000001a0b000 CR4: 00000000000007e0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> Stack:
>  ffff88007b7cde28 0000000300000000 ffff88007b7cde28 ffff88003756c130
>  0000000000000282 ffff88003756c128 ffffffff81227670 0000000000000000
>  ffff88007b7cde78 ffffffff810722b7 ffff88007cdcf000 ffffffff81a90540
> Call Trace:
>  [<ffffffff81227670>] ? crypto_alloc_pcomp+0x20/0x20
>  [<ffffffff810722b7>] complete_all+0x47/0x60
>  [<ffffffff81227708>] cryptomgr_probe+0x98/0xc0
>  [<ffffffff81227670>] ? crypto_alloc_pcomp+0x20/0x20
>  [<ffffffff8106760e>] kthread+0xce/0xe0
>  [<ffffffff81067540>] ? kthread_freezable_should_stop+0x70/0x70
>  [<ffffffff815450dc>] ret_from_fork+0x7c/0xb0
>  [<ffffffff81067540>] ? kthread_freezable_should_stop+0x70/0x70
> Code: 41 56 41 55 41 54 53 48 83 ec 18 66 66 66 66 90 89 75 cc 89 55 c8
>       4c 8d 6f 08 48 8b 57 08 41 89 cf 4d 89 c6 48 8d 42 e
> RIP  [<ffffffff81070321>] __wake_up_common+0x31/0x90
>  RSP <ffff88007b7cde08>
> CR2: 0000000000000000
> ---[ end trace b495b19270a4d37e ]---
> 
> My assumption is that the following is happening: the minimal SCTP
> tool runs under ``echo 1 > /proc/sys/net/sctp/auth_enable'', hence
> it's making use of crypto_alloc_hash() via sctp_auth_init_hmacs().
> It forks itself, heavily allocates, binds, listens and waits in
> accept on sctp sockets, and then randomly kills some of them (no
> need for an actual client in this case to hit this). Then, again,
> allocating, binding, etc, and then killing child processes.
> 
> The problem that might be happening here is that cryptomgr requests
> the module to probe/load through cryptomgr_schedule_probe(), but
> before the thread handler cryptomgr_probe() returns, we return from
> the wait_for_completion_interruptible() function and probably already
> have cleared up larval, thus we run into a NULL pointer dereference
> when in cryptomgr_probe() complete_all() is being called.
> 
> If we wait with wait_for_completion() instead, this panic will not
> occur anymore. This is valid, because in case a signal is pending,
> cryptomgr_probe() returns from probing anyway with properly calling
> complete_all().

The use of wait_for_completion_interruptible is intentional so that
we don't lock up the thread if a bug causes us to never wake up.

This bug is caused by the helper thread using the larval without
holding a reference count on it.  If the helper thread completes
after the original thread requesting for help has gone away and
destroyed the larval, then we get the crash above.

So the fix is to hold a reference count on the larval.

Cc: <stable@vger.kernel.org> # 3.6+
Reported-by: Daniel Borkmann <dborkman@redhat.com>
Tested-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
powerpc/eeh: Add eeh_dev to the cache during boot

commit f8f7d63fd96ead101415a1302035137a866f8998 ("powerpc/eeh: Trace eeh
device from I/O cache") broke EEH on pseries for devices that were
present during boot and have not been hotplugged/DLPARed.

eeh_check_failure will get the eeh_dev from the cache, and will get
NULL. eeh_addr_cache_build adds the addresses to the cache, but eeh_dev
for the giving pci_device is not set yet. Just reordering the call to
eeh_addr_cache_insert_dev works fine. The ordering is similar to the one
in eeh_add_device_late.

Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@linux.vnet.ibm.com>
Acked-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
drm/qxl: add missing access check for execbuffer ioctl

Reported-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Fix: kernel/ptrace.c: ptrace_peek_siginfo() missing __put_user() validation

This __put_user() could be used by unprivileged processes to write into
kernel memory.  The issue here is that even if copy_siginfo_to_user()
fails, the error code is not checked before __put_user() is executed.

Luckily, ptrace_peek_siginfo() has been added within the 3.10-rc cycle,
so it has not hit a stable release yet.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Andrey Vagin <avagin@openvz.org>
Cc: Roland McGrath <roland@redhat.com>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Pedro Alves <palves@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge branch 'drm-fixes' of git://people.freedesktop.org/~airlied/linux

Pull drm/qxl fix from Dave Airlie:
 "Bad me forgot an access check, possible security issue, but since this
  is the first kernel with it, should be fine to just put it in now"

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux:
  drm/qxl: add missing access check for execbuffer ioctl
Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6

Pull crypto fix from Herbert Xu:
 "This fixes a crash in the crypto layer exposed by an SCTP test tool"

* git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
  crypto: algboss - Hold ref count on larval
powerpc/pci: Improve device hotplug initialization

Commit 37f02195b (powerpc/pci: fix PCI-e devices rescan issue on powerpc
platform) fixes a problem with interrupt and DMA initialization on hot
plugged devices. With this commit, interrupt and DMA initialization for
hot plugged devices is handled in the pci device enable function.

This approach has a couple of drawbacks. First, it creates two code paths
for device initialization, one for hot plugged devices and another for devices
known during the initial PCI scan. Second, the initialization code for hot
plugged devices is only called when the device is enabled, ie typically
in the probe function. Also, the platform specific setup code is called each
time pci_enable_device() is called, not only once during device discovery,
meaning it is actually called multiple times, once for devices discovered
during the initial scan and again each time a driver is re-loaded.

The visible result is that interrupt pins are only assigned to hot plugged
devices when the device driver is loaded. Effectively this changes the PCI
probe API, since pci_dev->irq and the device's dma configuration will now
only be valid after pci_enable() was called at least once. A more subtle
change is that platform specific PCI device setup is moved from device
discovery into the driver's probe function, more specifically into the
pci_enable_device() call.

To fix the inconsistencies, add new function pcibios_add_device.
Call pcibios_setup_device from pcibios_setup_bus_devices if device setup
is not complete, and from pcibios_add_device if bus setup is complete.

With this change, device setup code is moved back into device initialization,
and called exactly once for both static and hot plugged devices.

[ This also fixes a regression introduced by the above patch which
  causes dev->irq to be overwritten under some cirumstances after
  MSIs have been enabled for the device which leads to crashes due
  to the MSI core "hijacking" dev->irq to store the base MSI number
  and not the LSI. --BenH
]

Cc: Yuanquan Chen <Yuanquan.Chen@freescale.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Hiroo Matsumoto <matsumoto.hiroo@jp.fujitsu.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
ARM: dt: Only print warning, not WARN() on bad cpu map in device tree

Due to recent changes and expecations of proper cpu bindings, there are
now cases for many of the in-tree devicetrees where a WARN() will hit
on boot due to badly formatted /cpus nodes.

Downgrade this to a pr_warn() to be less alarmist, since it's not a
new problem.

Tested on Arndale, Cubox, Seaboard and Panda ES. Panda hits the WARN
without this, the others do not.

Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge branch 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc

Pull powerpc fixes from Ben Herrenschmidt:
 "We discovered some breakage in our "EEH" (PCI Error Handling) code
  while doing error injection, due to a couple of regressions.  One of
  them is due to a patch (37f02195bee9 "powerpc/pci: fix PCI-e devices
  rescan issue on powerpc platform") that, in hindsight, I shouldn't
  have merged considering that it caused more problems than it solved.

  Please pull those two fixes.  One for a simple EEH address cache
  initialization issue.  The other one is a patch from Guenter that I
  had originally planned to put in 3.11 but which happens to also fix
  that other regression (a kernel oops during EEH error handling and
  possibly hotplug).

  With those two, the couple of test machines I've hammered with error
  injection are remaining up now.  EEH appears to still fail to recover
  on some devices, so there is another problem that Gavin is looking
  into but at least it's no longer crashing the kernel."

* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
  powerpc/pci: Improve device hotplug initialization
  powerpc/eeh: Add eeh_dev to the cache during boot