diff options
| author | dcashman <dcashman@google.com> | 2016-01-12 09:18:57 -0800 |
|---|---|---|
| committer | dcashman <dcashman@google.com> | 2016-01-12 09:20:39 -0800 |
| commit | ed0ff596bcaa39aad363b4eef2c77814f241361e (patch) | |
| tree | 9be1932ad14c4e17985212d1c74dd9ff0beb5832 /include | |
| parent | c85d30ec377a519645dac14c7595e3883ed6edf7 (diff) | |
| download | hikey-linaro-ed0ff596bcaa39aad363b4eef2c77814f241361e.tar.gz | |
FROMLIST: mm: mmap: Add new /proc tunable for mmap_base ASLR.
(cherry picked from commit https://lkml.org/lkml/2015/12/21/337)
ASLR only uses as few as 8 bits to generate the random offset for the
mmap base address on 32 bit architectures. This value was chosen to
prevent a poorly chosen value from dividing the address space in such
a way as to prevent large allocations. This may not be an issue on all
platforms. Allow the specification of a minimum number of bits so that
platforms desiring greater ASLR protection may determine where to place
the trade-off.
Bug: 24047224
Signed-off-by: Daniel Cashman <dcashman@android.com>
Signed-off-by: Daniel Cashman <dcashman@google.com>
Change-Id: Ibf9ed3d4390e9686f5cc34f605d509a20d40e6c2
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/mm.h | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index d57fe6c627c1..b1b7c8bebbd6 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -49,6 +49,17 @@ extern int sysctl_legacy_va_layout; #define sysctl_legacy_va_layout 0 #endif +#ifdef CONFIG_HAVE_ARCH_MMAP_RND_BITS +extern const int mmap_rnd_bits_min; +extern const int mmap_rnd_bits_max; +extern int mmap_rnd_bits __read_mostly; +#endif +#ifdef CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS +extern const int mmap_rnd_compat_bits_min; +extern const int mmap_rnd_compat_bits_max; +extern int mmap_rnd_compat_bits __read_mostly; +#endif + #include <asm/page.h> #include <asm/pgtable.h> #include <asm/processor.h> |