--- zzzz-none-000/linux-3.10.107/arch/tile/mm/mmap.c 2017-06-27 09:49:32.000000000 +0000 +++ scorpion-7490-727/linux-3.10.107/arch/tile/mm/mmap.c 2021-02-04 17:41:59.000000000 +0000 @@ -58,18 +58,36 @@ #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; - mm->unmap_area = arch_unmap_area; } else { mm->mmap_base = mmap_base(mm); mm->get_unmapped_area = arch_get_unmapped_area_topdown; - mm->unmap_area = arch_unmap_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; +}