diff options
| author | dcashman <dcashman@google.com> | 2016-01-12 09:18:57 -0800 |
|---|---|---|
| committer | John Stultz <john.stultz@linaro.org> | 2016-02-16 13:54:14 -0800 |
| commit | d49d88766ba924b3df96d9fc1c1a257b90970b74 (patch) | |
| tree | 47b3e74a9e80db79d26c4c6ba4c5bc992b96a403 /kernel/sysctl.c | |
| parent | 29a4f01daa11254debe7aba980681bb838dfff1b (diff) | |
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 'kernel/sysctl.c')
| -rw-r--r-- | kernel/sysctl.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 81fe3bde9fee..35bfe0c1360b 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -1577,6 +1577,28 @@ static struct ctl_table vm_table[] = { .mode = 0644, .proc_handler = proc_doulongvec_minmax, }, +#ifdef CONFIG_HAVE_ARCH_MMAP_RND_BITS + { + .procname = "mmap_rnd_bits", + .data = &mmap_rnd_bits, + .maxlen = sizeof(mmap_rnd_bits), + .mode = 0600, + .proc_handler = proc_dointvec_minmax, + .extra1 = (void *)&mmap_rnd_bits_min, + .extra2 = (void *)&mmap_rnd_bits_max, + }, +#endif +#ifdef CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS + { + .procname = "mmap_rnd_compat_bits", + .data = &mmap_rnd_compat_bits, + .maxlen = sizeof(mmap_rnd_compat_bits), + .mode = 0600, + .proc_handler = proc_dointvec_minmax, + .extra1 = (void *)&mmap_rnd_compat_bits_min, + .extra2 = (void *)&mmap_rnd_compat_bits_max, + }, +#endif { } }; |