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  1. 26 Feb, 2016 33 commits
  3. 25 Feb, 2016 7 commits
    • Greg Kroah-Hartman's avatar
      Linux 4.4.3 · 2134d97a
      Greg Kroah-Hartman authored
      2134d97a
    • Luis R. Rodriguez's avatar
      modules: fix modparam async_probe request · e2f712dc
      Luis R. Rodriguez authored 
      commit 4355efbd upstream.

Commit f2411da7 ("driver-core: add driver module
asynchronous probe support") added async probe support,
in two forms:

  * in-kernel driver specification annotation
  * generic async_probe module parameter (modprobe foo async_probe)

To support the generic kernel parameter parse_args() was
extended via commit ecc86170 ("module: add extra
argument for parse_params() callback") however commit
failed to f2411da7 failed to add the required argument.

This causes a crash then whenever async_probe generic
module parameter is used. This was overlooked when the
form in which in-kernel async probe support was reworked
a bit... Fix this as originally intended.

Cc: Hannes Reinecke <hare@suse.de>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: default avatarLuis R. Rodriguez <mcgrof@suse.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> [minimized]
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      e2f712dc
    • Rusty Russell's avatar
      module: wrapper for symbol name. · a24d9a2f
      Rusty Russell authored 
      commit 2e7bac53 upstream.

This trivial wrapper adds clarity and makes the following patch
smaller.
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      a24d9a2f
    • Thomas Gleixner's avatar
      itimers: Handle relative timers with CONFIG_TIME_LOW_RES proper · 82e730ba
      Thomas Gleixner authored 
      commit 51cbb524 upstream.

As Helge reported for timerfd we have the same issue in itimers. We return
remaining time larger than the programmed relative time to user space in case
of CONFIG_TIME_LOW_RES=y. Use the proper function to adjust the extra time
added in hrtimer_start_range_ns().
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Helge Deller <deller@gmx.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: linux-m68k@lists.linux-m68k.org
Cc: dhowells@redhat.com
Link: http://lkml.kernel.org/r/20160114164159.528222587@linutronix.deSigned-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      82e730ba
    • Thomas Gleixner's avatar
      posix-timers: Handle relative timers with CONFIG_TIME_LOW_RES proper · 1c94da3e
      Thomas Gleixner authored 
      commit 572c3917 upstream.

As Helge reported for timerfd we have the same issue in posix timers. We
return remaining time larger than the programmed relative time to user space
in case of CONFIG_TIME_LOW_RES=y. Use the proper function to adjust the extra
time added in hrtimer_start_range_ns().
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Helge Deller <deller@gmx.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: linux-m68k@lists.linux-m68k.org
Cc: dhowells@redhat.com
Link: http://lkml.kernel.org/r/20160114164159.450510905@linutronix.deSigned-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      1c94da3e
    • Thomas Gleixner's avatar
      timerfd: Handle relative timers with CONFIG_TIME_LOW_RES proper · 565f2229
      Thomas Gleixner authored 
      commit b62526ed upstream.

Helge reported that a relative timer can return a remaining time larger than
the programmed relative time on parisc and other architectures which have
CONFIG_TIME_LOW_RES set. This happens because we add a jiffie to the resulting
expiry time to prevent short timeouts.

Use the new function hrtimer_expires_remaining_adjusted() to calculate the
remaining time. It takes that extra added time into account for relative
timers.
Reported-and-tested-by: default avatarHelge Deller <deller@gmx.de>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: linux-m68k@lists.linux-m68k.org
Cc: dhowells@redhat.com
Link: http://lkml.kernel.org/r/20160114164159.354500742@linutronix.deSigned-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      565f2229
    • Mateusz Guzik's avatar
      prctl: take mmap sem for writing to protect against others · e5e99792
      Mateusz Guzik authored 
      commit ddf1d398 upstream.

An unprivileged user can trigger an oops on a kernel with
CONFIG_CHECKPOINT_RESTORE.

proc_pid_cmdline_read takes mmap_sem for reading and obtains args + env
start/end values. These get sanity checked as follows:
        BUG_ON(arg_start > arg_end);
        BUG_ON(env_start > env_end);

These can be changed by prctl_set_mm. Turns out also takes the semaphore for
reading, effectively rendering it useless. This results in:

  kernel BUG at fs/proc/base.c:240!
  invalid opcode: 0000 [#1] SMP
  Modules linked in: virtio_net
  CPU: 0 PID: 925 Comm: a.out Not tainted 4.4.0-rc8-next-20160105dupa+ #71
  Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
  task: ffff880077a68000 ti: ffff8800784d0000 task.ti: ffff8800784d0000
  RIP: proc_pid_cmdline_read+0x520/0x530
  RSP: 0018:ffff8800784d3db8  EFLAGS: 00010206
  RAX: ffff880077c5b6b0 RBX: ffff8800784d3f18 RCX: 0000000000000000
  RDX: 0000000000000002 RSI: 00007f78e8857000 RDI: 0000000000000246
  RBP: ffff8800784d3e40 R08: 0000000000000008 R09: 0000000000000001
  R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000050
  R13: 00007f78e8857800 R14: ffff88006fcef000 R15: ffff880077c5b600
  FS:  00007f78e884a740(0000) GS:ffff88007b200000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
  CR2: 00007f78e8361770 CR3: 00000000790a5000 CR4: 00000000000006f0
  Call Trace:
    __vfs_read+0x37/0x100
    vfs_read+0x82/0x130
    SyS_read+0x58/0xd0
    entry_SYSCALL_64_fastpath+0x12/0x76
  Code: 4c 8b 7d a8 eb e9 48 8b 9d 78 ff ff ff 4c 8b 7d 90 48 8b 03 48 39 45 a8 0f 87 f0 fe ff ff e9 d1 fe ff ff 4c 8b 7d 90 eb c6 0f 0b <0f> 0b 0f 0b 66 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00
  RIP   proc_pid_cmdline_read+0x520/0x530
  ---[ end trace 97882617ae9c6818 ]---

Turns out there are instances where the code just reads aformentioned
values without locking whatsoever - namely environ_read and get_cmdline.

Interestingly these functions look quite resilient against bogus values,
but I don't believe this should be relied upon.

The first patch gets rid of the oops bug by grabbing mmap_sem for
writing.

The second patch is optional and puts locking around aformentioned
consumers for safety.  Consumers of other fields don't seem to benefit
from similar treatment and are left untouched.

This patch (of 2):

The code was taking the semaphore for reading, which does not protect
against readers nor concurrent modifications.

The problem could cause a sanity checks to fail in procfs's cmdline
reader, resulting in an OOPS.

Note that some functions perform an unlocked read of various mm fields,
but they seem to be fine despite possible modificaton.
Signed-off-by: default avatarMateusz Guzik <mguzik@redhat.com>
Acked-by: default avatarCyrill Gorcunov <gorcunov@openvz.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Jarod Wilson <jarod@redhat.com>
Cc: Jan Stancek <jstancek@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Anshuman Khandual <anshuman.linux@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      e5e99792
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