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  1. 28 6月, 2017 2 次提交
  3. 19 6月, 2017 1 次提交
    • H
      mm: larger stack guard gap, between vmas · 1be7107f
      由 Hugh Dickins 提交于 
      Stack guard page is a useful feature to reduce a risk of stack smashing
into a different mapping. We have been using a single page gap which
is sufficient to prevent having stack adjacent to a different mapping.
But this seems to be insufficient in the light of the stack usage in
userspace. E.g. glibc uses as large as 64kB alloca() in many commonly
used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX]
which is 256kB or stack strings with MAX_ARG_STRLEN.

This will become especially dangerous for suid binaries and the default
no limit for the stack size limit because those applications can be
tricked to consume a large portion of the stack and a single glibc call
could jump over the guard page. These attacks are not theoretical,
unfortunatelly.

Make those attacks less probable by increasing the stack guard gap
to 1MB (on systems with 4k pages; but make it depend on the page size
because systems with larger base pages might cap stack allocations in
the PAGE_SIZE units) which should cover larger alloca() and VLA stack
allocations. It is obviously not a full fix because the problem is
somehow inherent, but it should reduce attack space a lot.

One could argue that the gap size should be configurable from userspace,
but that can be done later when somebody finds that the new 1MB is wrong
for some special case applications.  For now, add a kernel command line
option (stack_guard_gap) to specify the stack gap size (in page units).

Implementation wise, first delete all the old code for stack guard page:
because although we could get away with accounting one extra page in a
stack vma, accounting a larger gap can break userspace - case in point,
a program run with "ulimit -S -v 20000" failed when the 1MB gap was
counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK
and strict non-overcommit mode.

Instead of keeping gap inside the stack vma, maintain the stack guard
gap as a gap between vmas: using vm_start_gap() in place of vm_start
(or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few
places which need to respect the gap - mainly arch_get_unmapped_area(),
and and the vma tree's subtree_gap support for that.
Original-patch-by: NOleg Nesterov <oleg@redhat.com>
Original-patch-by: NMichal Hocko <mhocko@suse.com>
Signed-off-by: NHugh Dickins <hughd@google.com>
Acked-by: NMichal Hocko <mhocko@suse.com>
Tested-by: Helge Deller <deller@gmx.de> # parisc
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      1be7107f
  5. 08 6月, 2017 1 次提交
  7. 05 6月, 2017 1 次提交
  9. 02 6月, 2017 1 次提交
  11. 01 6月, 2017 1 次提交
  13. 31 5月, 2017 1 次提交
  15. 28 5月, 2017 1 次提交
  17. 25 5月, 2017 1 次提交
  19. 23 5月, 2017 3 次提交
  21. 22 5月, 2017 2 次提交
  23. 19 5月, 2017 1 次提交
    • P
      iTCO_wdt: all versions count down twice · 1fccb730
      由 Paolo Bonzini 提交于 
      The ICH9 is listed as having TCO v2, and indeed the behavior in the
datasheet corresponds to v2 (for example the NO_REBOOT flag is
accessible via the 16KiB-aligned Root Complex Base Address).

However, the TCO counts twice just like in v1; the documentation
of the SECOND_TO_STS bit says: "ICH9 sets this bit to 1 to indicate
that the TIMEOUT bit had been (or is currently) set and a second
timeout occurred before the TCO_RLD register was written. If this
bit is set and the NO_REBOOT config bit is 0, then the ICH9 will
reboot the system after the second timeout.  The same can be found
in the BayTrail (Atom E3800) datasheet, and even HOWTOs around
the Internet say that it will reboot after _twice_ the specified
heartbeat.

I did not find the Apollo Lake datasheet, but because v4/v5 has
a SECOND_TO_STS bit just like the previous version I'm enabling
this for Apollo Lake as well.

Cc: linux-watchdog@vger.kernel.org
Reviewed-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>
      1fccb730
  25. 17 5月, 2017 1 次提交
    • M
      doc-rst: fixed kernel-doc directives in usb/typec.rst · 5383fae7
      由 Markus Heiser 提交于 
      Even if this file is not yet included in any toctree, it is parsed by
Sphinx since it is named '.rst'. This patch fixes the following two
ERRORs from Sphinx build:

Documentation/usb/typec.rst:116: ERROR: Error in "kernel-doc" directive:
invalid option block.

.. kernel-doc:: drivers/usb/typec/typec.c
   :functions: typec_register_cable typec_unregister_cable typec_register_plug
   typec_unregister_plug

Documentation/usb/typec.rst:139: ERROR: Error in "kernel-doc" directive:
invalid option block.

.. kernel-doc:: drivers/usb/typec/typec.c
   :functions: typec_set_data_role typec_set_pwr_role typec_set_vconn_role
   typec_set_pwr_opmode
Signed-off-by: NMarkus Heiser <markus.heiser@darmarit.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      5383fae7
  27. 15 5月, 2017 1 次提交
  29. 14 5月, 2017 1 次提交
  31. 13 5月, 2017 3 次提交
  33. 12 5月, 2017 1 次提交
  35. 11 5月, 2017 1 次提交
  37. 10 5月, 2017 8 次提交
  39. 09 5月, 2017 6 次提交
  41. 08 5月, 2017 2 次提交