diff options
| -rw-r--r-- | arch/tile/include/asm/elf.h | 4 | ||||
| -rw-r--r-- | arch/tile/mm/mmap.c | 24 |
2 files changed, 26 insertions, 2 deletions
diff --git a/arch/tile/include/asm/elf.h b/arch/tile/include/asm/elf.h index 31d854f1b83b..e1da88e8aa9f 100644 --- a/arch/tile/include/asm/elf.h +++ b/arch/tile/include/asm/elf.h @@ -137,6 +137,10 @@ do { \ NEW_AUX_ENT(AT_SYSINFO_EHDR, VDSO_BASE); \ } while (0) +struct mm_struct; +extern unsigned long arch_randomize_brk(struct mm_struct *mm); +#define arch_randomize_brk arch_randomize_brk + #ifdef CONFIG_COMPAT #define COMPAT_ELF_PLATFORM "tilegx-m32" diff --git a/arch/tile/mm/mmap.c b/arch/tile/mm/mmap.c index d67d91ebf63e..851a94e6ae58 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; +} |