diff options
| author |   David Daney <ddaney@caviumnetworks.com> | 2010-07-19 13:14:57 -0700 |
|---|---|---|
| committer |   Ralf Baechle <ralf@linux-mips.org> | 2010-08-05 13:26:06 +0100 |
| commit | 652b14aa84961fa391184ccbaf559a537d33b28c (patch) | |
| tree | 748ba20efa1094728a85fe4d59d01ccbd6e1bfad /arch/mips/kernel/syscall.c | |
| parent | MIPS: Randomize mmap if randomize_va_space is set (diff) | |
| download | linux-dev-652b14aa84961fa391184ccbaf559a537d33b28c.tar.xz linux-dev-652b14aa84961fa391184ccbaf559a537d33b28c.zip | |
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 <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/1479/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/kernel/syscall.c')
| -rw-r--r-- | arch/mips/kernel/syscall.c | 28 |
1 files changed, 28 insertions, 0 deletions
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 <linux/uaccess.h> #include <linux/slab.h> #include <linux/random.h> +#include <linux/elf.h> #include <asm/asm.h> #include <asm/branch.h> @@ -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) |