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authorPrem Karat <pkarat@mvista.com>2014-04-21 09:33:16 +0530
committerRalf Baechle <ralf@linux-mips.org>2014-11-24 07:45:38 +0100
commitccd3988086364837d0c0fb4563d715c691636313 (patch)
treeb32a646617d76d570cfe20d64483d3b3aef10c39 /arch/mips
parentac41f9c46282926c92b8bd0dcb1aca29a97d13ab (diff)
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/mips')
-rw-r--r--arch/mips/kernel/vdso.c15
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)