From 652b14aa84961fa391184ccbaf559a537d33b28c Mon Sep 17 00:00:00 2001 From: David Daney Date: Mon, 19 Jul 2010 13:14:57 -0700 Subject: MIPS: Enable heap randomization. Based somewhat on the PPC implementation. 32-bit processes have the heap randomized in an 8MB space, 256MB for 64-bit processes. Signed-off-by: David Daney To: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/1479/ Signed-off-by: Ralf Baechle --- arch/mips/kernel/syscall.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) (limited to 'arch/mips/kernel/syscall.c') diff --git a/arch/mips/kernel/syscall.c b/arch/mips/kernel/syscall.c index 9824a829f61d..58bab2ef257f 100644 --- a/arch/mips/kernel/syscall.c +++ b/arch/mips/kernel/syscall.c @@ -30,6 +30,7 @@ #include #include #include +#include #include #include @@ -153,6 +154,33 @@ void arch_pick_mmap_layout(struct mm_struct *mm) mm->unmap_area = arch_unmap_area; } +static inline unsigned long brk_rnd(void) +{ + unsigned long rnd = get_random_int(); + + rnd = rnd << PAGE_SHIFT; + /* 8MB for 32bit, 256MB for 64bit */ + if (TASK_IS_32BIT_ADDR) + rnd = rnd & 0x7ffffful; + else + rnd = rnd & 0xffffffful; + + return rnd; +} + +unsigned long arch_randomize_brk(struct mm_struct *mm) +{ + unsigned long base = mm->brk; + unsigned long ret; + + ret = PAGE_ALIGN(base + brk_rnd()); + + if (ret < mm->brk) + return mm->brk; + + return ret; +} + SYSCALL_DEFINE6(mips_mmap, unsigned long, addr, unsigned long, len, unsigned long, prot, unsigned long, flags, unsigned long, fd, off_t, offset) -- cgit v1.2.3