From: Anton Blanchard <anton@samba•org>
To: linuxppc-dev@ozlabs•org
Subject: [patch 07/10] powerpc: Randomise the brk region
Date: Sun, 22 Feb 2009 22:50:04 +1100 [thread overview]
Message-ID: <20090222115332.546296226@samba.org> (raw)
In-Reply-To: 20090222114957.213647384@samba.org
Randomize the heap.
before:
tundro2:~ # sleep 1 & cat /proc/${!}/maps | grep heap
10017000-10118000 rw-p 10017000 00:00 0 [heap]
10017000-10118000 rw-p 10017000 00:00 0 [heap]
10017000-10118000 rw-p 10017000 00:00 0 [heap]
10017000-10118000 rw-p 10017000 00:00 0 [heap]
10017000-10118000 rw-p 10017000 00:00 0 [heap]
after
tundro2:~ # sleep 1 & cat /proc/${!}/maps | grep heap
19419000-1951a000 rw-p 19419000 00:00 0 [heap]
325ff000-32700000 rw-p 325ff000 00:00 0 [heap]
1a97c000-1aa7d000 rw-p 1a97c000 00:00 0 [heap]
1cc60000-1cd61000 rw-p 1cc60000 00:00 0 [heap]
1afa9000-1b0aa000 rw-p 1afa9000 00:00 0 [heap]
Signed-off-by: Anton Blanchard <anton@samba•org>
---
Index: linux-2.6/arch/powerpc/include/asm/elf.h
===================================================================
--- linux-2.6.orig/arch/powerpc/include/asm/elf.h 2009-02-20 16:06:32.000000000 +1100
+++ linux-2.6/arch/powerpc/include/asm/elf.h 2009-02-22 11:58:02.000000000 +1100
@@ -275,6 +275,9 @@
(0x7ff >> (PAGE_SHIFT - 12)) : \
(0x3ffff >> (PAGE_SHIFT - 12)))
+extern unsigned long arch_randomize_brk(struct mm_struct *mm);
+#define arch_randomize_brk arch_randomize_brk
+
#endif /* __KERNEL__ */
/*
Index: linux-2.6/arch/powerpc/kernel/process.c
===================================================================
--- linux-2.6.orig/arch/powerpc/kernel/process.c 2009-02-20 16:06:32.000000000 +1100
+++ linux-2.6/arch/powerpc/kernel/process.c 2009-02-22 11:58:02.000000000 +1100
@@ -1131,3 +1131,26 @@
sp -= get_random_int() & ~PAGE_MASK;
return sp & ~0xf;
}
+
+static inline unsigned long brk_rnd(void)
+{
+ unsigned long rnd = 0;
+
+ /* 8MB for 32bit, 1GB for 64bit */
+ if (is_32bit_task())
+ rnd = (long)(get_random_int() % (1<<(23-PAGE_SHIFT)));
+ else
+ rnd = (long)(get_random_int() % (1<<(30-PAGE_SHIFT)));
+
+ return rnd << PAGE_SHIFT;
+}
+
+unsigned long arch_randomize_brk(struct mm_struct *mm)
+{
+ unsigned long ret = PAGE_ALIGN(mm->brk + brk_rnd());
+
+ if (ret < mm->brk)
+ return mm->brk;
+
+ return ret;
+}
--
next prev parent reply other threads:[~2009-02-22 11:50 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-22 11:49 [patch 00/10] PowerPC address space randomisation Anton Blanchard
2009-02-22 11:49 ` [patch 01/10] powerpc: Move is_32bit_task Anton Blanchard
2009-02-22 11:49 ` [patch 02/10] powerpc: Use new layout for 64bit binaries Anton Blanchard
2009-02-22 11:50 ` [patch 03/10] powerpc: Rearrange mmap.c Anton Blanchard
2009-02-22 11:50 ` [patch 04/10] powerpc: Randomise mmap start address Anton Blanchard
2009-02-22 11:50 ` [patch 05/10] powerpc: More stack randomisation for 64bit binaries Anton Blanchard
2009-02-22 11:50 ` [patch 06/10] powerpc: Randomise lower bits of stack address Anton Blanchard
2009-02-22 11:50 ` Anton Blanchard [this message]
2009-02-22 11:50 ` [patch 08/10] powerpc: Ensure random space between stack and mmaps Anton Blanchard
2009-02-22 11:50 ` [patch 09/10] powerpc: Increase stack gap on 64bit binaries Anton Blanchard
2009-02-22 11:50 ` [patch 10/10] powerpc: Randomise PIEs Anton Blanchard
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