diff options
| author | Tony Lu <zlu@tilera.com> | 2013-08-09 15:45:24 -0400 |
|---|---|---|
| committer | Chris Metcalf <cmetcalf@tilera.com> | 2013-08-30 11:56:25 -0400 |
| commit | b2eca4274c1813c76291eab4859ca3e86e6fd35b (patch) | |
| tree | ad4e951e630cb4fa4ff5e6cf484ba9cab9e466d1 /arch/tile/mm/mmap.c | |
| parent | 9b5bbf729d2db27ecb477b42c0701c1c97eb5603 (diff) | |
tile: support ASLR fully
With this change, tile Linux now supports address-space layout
randomization for shared objects, stack, heap and vdso.
Acked-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Tony Lu <zlu@tilera.com>
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
Diffstat (limited to 'arch/tile/mm/mmap.c')
| -rw-r--r-- | arch/tile/mm/mmap.c | 24 |
1 files changed, 22 insertions, 2 deletions
diff --git a/arch/tile/mm/mmap.c b/arch/tile/mm/mmap.c index d67d91ebf63..851a94e6ae5 100644 --- a/arch/tile/mm/mmap.c +++ b/arch/tile/mm/mmap.c @@ -58,16 +58,36 @@ void arch_pick_mmap_layout(struct mm_struct *mm) #else int is_32bit = 0; #endif + unsigned long random_factor = 0UL; + + /* + * 8 bits of randomness in 32bit mmaps, 24 address space bits + * 12 bits of randomness in 64bit mmaps, 28 address space bits + */ + if (current->flags & PF_RANDOMIZE) { + if (is_32bit) + random_factor = get_random_int() % (1<<8); + else + random_factor = get_random_int() % (1<<12); + + random_factor <<= PAGE_SHIFT; + } /* * Use standard layout if the expected stack growth is unlimited * or we are running native 64 bits. */ - if (!is_32bit || rlimit(RLIMIT_STACK) == RLIM_INFINITY) { - mm->mmap_base = TASK_UNMAPPED_BASE; + if (rlimit(RLIMIT_STACK) == RLIM_INFINITY) { + mm->mmap_base = TASK_UNMAPPED_BASE + random_factor; mm->get_unmapped_area = arch_get_unmapped_area; } else { mm->mmap_base = mmap_base(mm); mm->get_unmapped_area = arch_get_unmapped_area_topdown; } } + +unsigned long arch_randomize_brk(struct mm_struct *mm) +{ + unsigned long range_end = mm->brk + 0x02000000; + return randomize_range(mm->brk, range_end, 0) ? : mm->brk; +} |