diff options
| author | Anton Blanchard <anton@samba.org> | 2009-02-22 01:50:02 +0000 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2009-02-23 15:53:07 +1100 |
| commit | 2dadb987e09995b2910c419cdfe2307e66537649 (patch) | |
| tree | 963530a0ee6a54f6067e6d267f5861094426e1be | |
| parent | 9f14c42d7582bf33bbe1e133d897a6942ceae08e (diff) | |
powerpc: More stack randomisation for 64bit binaries
At the moment we randomise the stack by 8MB on 32bit and 64bit tasks. Since we
have a lot more address space to play with on 64bit, lets do what x86 does and
increase that randomisation to 1GB:
before:
# for i in seq `1 10` ; do sleep 1 & cat /proc/${!}/maps | grep stack; done
fffffebc000-fffffed1000 rw-p ffffffeb000 00:00 0 [stack]
ffffff5a000-ffffff6f000 rw-p ffffffeb000 00:00 0 [stack]
fffffdb2000-fffffdc7000 rw-p ffffffeb000 00:00 0 [stack]
fffffd3e000-fffffd53000 rw-p ffffffeb000 00:00 0 [stack]
fffffad9000-fffffaee000 rw-p ffffffeb000 00:00 0 [stack]
after:
# for i in seq `1 10` ; do sleep 1 & cat /proc/${!}/maps | grep stack; done
ffff5c27000-ffff5c3c000 rw-p ffffffeb000 00:00 0 [stack]
fffebe5e000-fffebe73000 rw-p ffffffeb000 00:00 0 [stack]
fffcb298000-fffcb2ad000 rw-p ffffffeb000 00:00 0 [stack]
fffc719d000-fffc71b2000 rw-p ffffffeb000 00:00 0 [stack]
fffe01af000-fffe01c4000 rw-p ffffffeb000 00:00 0 [stack]
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
| -rw-r--r-- | arch/powerpc/include/asm/elf.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/elf.h b/arch/powerpc/include/asm/elf.h index c125da793b0..3f94d8880e6 100644 --- a/arch/powerpc/include/asm/elf.h +++ b/arch/powerpc/include/asm/elf.h @@ -271,6 +271,11 @@ extern int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp); #define VDSO_AUX_ENT(a,b) NEW_AUX_ENT(a,b); +/* 1GB for 64bit, 8MB for 32bit */ +#define STACK_RND_MASK (is_32bit_task() ? \ + (0x7ff >> (PAGE_SHIFT - 12)) : \ + (0x3ffff >> (PAGE_SHIFT - 12))) + #endif /* __KERNEL__ */ /* |