diff options
| author | Prem Karat <pkarat@mvista.com> | 2014-04-21 06:03:16 +0200 |
|---|---|---|
| committer | Ralf Baechle <ralf@linux-mips.org> | 2014-11-24 07:45:38 +0100 |
| commit | ccd3988086364837d0c0fb4563d715c691636313 (patch) | |
| tree | b32a646617d76d570cfe20d64483d3b3aef10c39 /arch | |
| parent | MIPS: Remove a temporary hack for debugging cache flushes in SMTC configuration (diff) | |
| download | linux-ccd3988086364837d0c0fb4563d715c691636313.tar.xz linux-ccd3988086364837d0c0fb4563d715c691636313.zip | |
MIPS: Enable VDSO randomization
Based on commit 1091458d09e1a (mmap randomization)
For 32-bit address spaces randomize within a
16MB space, for 64-bit within a 256MB space.
Test Results:
------------
Without Patch (VDSO is not randomized)
---------------------------------------
root@Maleo:~# ./aslr vdso
FAIL: ASLR not functional (vdso always at 0x7fff7000)
root@Maleo:~# ./aslr rekey vdso
pre_val==cur_val
value=0x7fff7000
With patch:(VDSO is randmoized and doesn't interfere with stack)
----------------------------------------------------------------
root@cavium-octeon2:~# ./aslr rekey vdso
pre_val!=cur_val
previous_value=0x7f830ea2
current_value=0x776e2000
root@cavium-octeon2:~# ./aslr rekey vdso
pre_val!=cur_val
previous_value=0x7fb0cea2
current_value=0x77209000
root@cavium-octeon2:~# ./aslr rekey vdso
pre_val!=cur_val
previous_value=0x7f985ea2
current_value=0x7770c000
root@cavium-octeon2:~# ./aslr rekey vdso
pre_val!=cur_val
previous_value=0x7fbc6ea2
current_value=0x7fe25000
Maps file output:
-------------------------
root@cavium-octeon2:~# ./aslr rekey maps
78584000-785a5000 rwxp 00000000 00:00 0 [heap]
7f9d0000-7f9f1000 rw-p 00000000 00:00 0 [stack]
7ffa5000-7ffa6000 r-xp 00000000 00:00 0 [vdso]
root@cavium-octeon2:~# ./aslr rekey maps
77de0000-77e01000 rwxp 00000000 00:00 0 [heap]
7f91b000-7f93c000 rw-p 00000000 00:00 0 [stack]
7ff99000-7ff9a000 r-xp 00000000 00:00 0 [vdso]
root@cavium-octeon2:~# ./aslr rekey maps
77d7f000-77da0000 rwxp 00000000 00:00 0 [heap]
7fc2a000-7fc4b000 rw-p 00000000 00:00 0 [stack]
7fe09000-7fe0a000 r-xp 00000000 00:00 0 [vdso]
root@cavium-octeon2:~# ./aslr rekey maps
7794c000-7794d000 r-xp 00000000 00:00 0 [vdso]
77e4b000-77e6c000 rwxp 00000000 00:00 0 [heap]
7f6e7000-7f708000 rw-p 00000000 00:00 0 [stack]
root@cavium-octeon2:~#
Signed-off-by: Prem Karat <pkarat@mvista.com>
Cc: linux-mips@linux-mips.org
Cc: sergei.shtylyov@cogentembedded.com
Cc: ddaney.cavm@gmail.com
Patchwork: https://patchwork.linux-mips.org/patch/6812
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/mips/kernel/vdso.c | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/arch/mips/kernel/vdso.c b/arch/mips/kernel/vdso.c index 0f1af58b036a..ed2a278722a9 100644 --- a/arch/mips/kernel/vdso.c +++ b/arch/mips/kernel/vdso.c @@ -16,9 +16,11 @@ #include <linux/elf.h> #include <linux/vmalloc.h> #include <linux/unistd.h> +#include <linux/random.h> #include <asm/vdso.h> #include <asm/uasm.h> +#include <asm/processor.h> /* * Including <asm/unistd.h> would give use the 64-bit syscall numbers ... @@ -67,7 +69,18 @@ subsys_initcall(init_vdso); static unsigned long vdso_addr(unsigned long start) { - return STACK_TOP; + unsigned long offset = 0UL; + + if (current->flags & PF_RANDOMIZE) { + offset = get_random_int(); + offset <<= PAGE_SHIFT; + if (TASK_IS_32BIT_ADDR) + offset &= 0xfffffful; + else + offset &= 0xffffffful; + } + + return STACK_TOP + offset; } int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) |