[cip-dev] [PATCH 4.4-cip 0/6] Extend user-space ASLR range

[ben.hutchings@codethink.co.uk (Ben Hutchings)]

This is a backport of changes in 4.5 to extend the range of Address
Space Layout Randomisation for user-space processes.  When enabled, this
should make some user-space vulnerabilities harder to exploit, but it
can also cause some applications to fail if they currently use a large
proportion of the virtual address space.

The default ASLR range remains the same, but it can be changed through
kernel config (CONFIG_ARCH_MMAP_RND_BITS) or at run-time through sysctl
(vm.mmap_rnd_bits).  (For 32-bit compat tasks, the range is controlled
through CONFIG_ARCH_MMAP_RND_COMPAT_BITS and vm.mmap_rnd_compat_bits.)

This includes support for arm, arm64 and x86 (32- and 64-bit).  (arm64
is not currently supported by CIP, but it was easier to include it in
the backport than to leave it out.)

For this and other backports, I'm looking for feedback like:
- Did I miss a follow-up fix or an earlier dependency?
- Does this cause a regression (other than as explained above)?
- Are you likely to use it?
- Are there related features you want in 4.4?

Ben.

Daniel Cashman (6):
  mm: mmap: add new /proc tunable for mmap_base ASLR
  arm: mm: support ARCH_MMAP_RND_BITS
  arm64: mm: support ARCH_MMAP_RND_BITS
  x86: mm: support ARCH_MMAP_RND_BITS
  drivers: char: random: add get_random_long()
  mm: ASLR: use get_random_long()

 Documentation/sysctl/vm.txt      | 29 +++++++++++++++++
 arch/Kconfig                     | 68 ++++++++++++++++++++++++++++++++++++++++
 arch/arm/Kconfig                 |  9 ++++++
 arch/arm/mm/mmap.c               |  3 +-
 arch/arm64/Kconfig               | 29 +++++++++++++++++
 arch/arm64/mm/mmap.c             |  8 +++--
 arch/mips/mm/mmap.c              |  4 +--
 arch/powerpc/kernel/process.c    |  4 +--
 arch/powerpc/mm/mmap.c           |  4 +--
 arch/sparc/kernel/sys_sparc_64.c |  2 +-
 arch/x86/Kconfig                 | 16 ++++++++++
 arch/x86/mm/mmap.c               | 12 +++----
 drivers/char/random.c            | 22 +++++++++++++
 fs/binfmt_elf.c                  |  2 +-
 include/linux/mm.h               | 11 +++++++
 include/linux/random.h           |  1 +
 kernel/sysctl.c                  | 22 +++++++++++++
 mm/mmap.c                        | 12 +++++++
 18 files changed, 240 insertions(+), 18 deletions(-)

-- 
2.10.2


-- 
Ben Hutchings
Software Developer, Codethink Ltd.