If the server is malicious then *bytes_read could be larger than the
size of the "target" buffer.  It would lead to memory corruption when we
do the memcpy().

Reported-by: Dr Silvio Cesare of InfoSect <Silvio Cesare <silvio.cesare@gmail.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

ashmem_mutex may create a chain of dependencies like:

CPU0                                    CPU1
 mmap syscall                           ioctl syscall
 -> mmap_sem (acquired)                 -> ashmem_ioctl
 -> ashmem_mmap                            -> ashmem_mutex (acquired)
    -> ashmem_mutex (try to acquire)       -> copy_from_user
                                              -> mmap_sem (try to acquire)

There is a lock odering problem between mmap_sem and ashmem_mutex causing
a lockdep splat[1] during a syzcaller test. This patch fixes the problem
by move copy_from_user out of ashmem_mutex.

[1] https://www.spinics.net/lists/kernel/msg2733200.html

Fixes: ce8a3a9e76d0 (staging: android: ashmem: Fix a race condition in pin ioctls)
Reported-by: syzbot+d7a918a7a8e1c952bc36@syzkaller.appspotmail.com
Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

A rounding error was causing comedi_nsamples_left to
return the wrong value when nsamples was not a multiple
of the scan length.

Cc: <stable@vger.kernel.org> # v4.4+
Signed-off-by: Frank Mori Hess <fmh6jj@gmail.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

ashmem_mutex create a chain of dependencies like so:

(1)
mmap syscall ->
  mmap_sem ->  (acquired)
  ashmem_mmap
  ashmem_mutex (try to acquire)
  (block)

(2)
llseek syscall ->
  ashmem_llseek ->
  ashmem_mutex ->  (acquired)
  inode_lock ->
  inode->i_rwsem (try to acquire)
  (block)

(3)
getdents ->
  iterate_dir ->
  inode_lock ->
  inode->i_rwsem   (acquired)
  copy_to_user ->
  mmap_sem         (try to acquire)

There is a lock ordering created between mmap_sem and inode->i_rwsem
causing a lockdep splat [2] during a syzcaller test, this patch fixes
the issue by unlocking the mutex earlier. Functionally that's Ok since
we don't need to protect vfs_llseek.

[1] https://patchwork.kernel.org/patch/10185031/
[2] https://lkml.org/lkml/2018/1/10/48

Acked-by: Todd Kjos <tkjos@google.com>
Cc: Arve Hjonnevag <arve@android.com>
Cc: stable@vger.kernel.org
Reported-by: syzbot+8ec30bb7bf1a981a2012@syzkaller.appspotmail.com
Signed-off-by: Joel Fernandes <joelaf@google.com>
Acked-by: Greg Hackmann <ghackmann@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Pull staging/IIO fixes from Greg KH:
 "Here are a small number of staging and iio driver fixes for 4.16-rc2.

  The IIO fixes are all for reported things, and the android driver
  fixes also resolve some reported problems. The remaining fsl-mc
  Kconfig change resolves a build testing error that Arnd reported.

  All of these have been in linux-next with no reported issues"

* tag 'staging-4.16-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
  iio: buffer: check if a buffer has been set up when poll is called
  iio: adis_lib: Initialize trigger before requesting interrupt
  staging: android: ion: Zero CMA allocated memory
  staging: android: ashmem: Fix a race condition in pin ioctls
  staging: fsl-mc: fix build testing on x86
  iio: srf08: fix link error "devm_iio_triggered_buffer_setup" undefined
  staging: iio: ad5933: switch buffer mode to software
  iio: adc: stm32: fix stm32h7_adc_enable error handling
  staging: iio: adc: ad7192: fix external frequency setting
  iio: adc: aspeed: Fix error handling path

Jonathan writes:

First round of IIO fixes for the 4.16 cycle.

One nasty very old crash around polling for buffers that aren't there
- though that can only cause effects on drivers that support events
but not buffers.

* buffer / kfifo handling in the core.
  - Check there is a buffer and return 0 from poll directly if there
    isn't.  Poll doesn't make sense in this circumstances, but best to close
    the hole.
* ad5933
  - Change the marked buffer mode to a software buffer as the meaning of
    the hardware buffer label has long since changed and this uses a front
    end software buffer anyway.
* ad7192
  - Fix the fact the external clock frequency was only set when using the
    internal clock which was less than helpful.
* adis_lib
  - Initialize the trigger before requesting the interrupt.  Some newer
    parts can power up with interrupt generation enabled so ordering now
    matters.
* aspeed-adc
  - Fix an errror handling path as labels and general ordering were wrong.
* srf08
  - Fix a link error due to undefined devm_iio_triggered_buffer_setup.
* stm32-adc
  - Fix error handling unwind squence in stm32h7_adc_enable.

Since commit 204f672255c2 ("staging: android: ion: Use CMA APIs directly")
the CMA API is now used directly and therefore the allocated memory is no
longer automatically zeroed.

Explicitly zero CMA allocated memory to ensure that no data is exposed to
userspace.

Fixes: 204f672255c2 ("staging: android: ion: Use CMA APIs directly")
Signed-off-by: Liam Mark <lmark@codeaurora.org>
Acked-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

ashmem_pin_unpin() reads asma->file and asma->size before taking the
ashmem_mutex, so it can race with other operations that modify them.

Build-tested only.

Cc: stable@vger.kernel.org
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Selecting GENERIC_MSI_IRQ_DOMAIN on x86 causes a compile-time error in
some configurations:

drivers/base/platform-msi.c:37:19: error: field 'arg' has incomplete type

On the other architectures, we are fine, but here we should have an additional
dependency on X86_LOCAL_APIC so we can get the PCI_MSI_IRQ_DOMAIN symbol.

Cc: stable@vger.kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

On some platforms there's an ITS available but it's not enabled
because reading or writing the registers is denied by the
firmware. In fact, reading or writing them will cause the system
to reset. We could remove the node from DT in such a case, but
it's better to skip nodes that are marked as "disabled" in DT so
that we can describe the hardware that exists and use the status
property to indicate how the firmware has configured things.

Cc: Stuart Yoder <stuyoder@gmail.com>
Cc: Laurentiu Tudor <laurentiu.tudor@nxp.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Rajendra Nayak <rnayak@codeaurora.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>