diff options
| author | dcashman <dcashman@google.com> | 2015-12-29 14:24:39 -0800 |
|---|---|---|
| committer | Moyster <oysterized@gmail.com> | 2016-09-10 16:51:12 +0200 |
| commit | bd4cf354cc5f4a7c5c64b5bae1f6167423ae39c2 (patch) | |
| tree | 12526b612248dd45f3454680401a584914d706c6 /kernel | |
| parent | fb9d96e62a68703f1861f14c68caa8a641b68978 (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: I66ac01c6f4f2c8dcfc84d1f1e99490b8385b3ed4
Diffstat (limited to 'kernel')
| -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 781dce655..85d56cf97 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -1510,6 +1510,28 @@ static struct ctl_table vm_table[] = { .extra1 = &zero, },*/ #endif +#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 { } }; |