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authorAnton Blanchard <anton@samba.org>2009-02-22 01:50:07 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2009-02-23 15:53:21 +1100
commit501cb16d3cfdcca99ac26fe122079f2a43b046b8 (patch)
tree90feee70ffa3e15857908f842e5764649141270b
parent002b0ec73dd8b784004e5a013ad9f2fa6274af5a (diff)
powerpc: Randomise PIEs
Randomise ELF_ET_DYN_BASE, which is used when loading position independent executables. 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.h3
-rw-r--r--arch/powerpc/kernel/process.c10
2 files changed, 12 insertions, 1 deletions
diff --git a/arch/powerpc/include/asm/elf.h b/arch/powerpc/include/asm/elf.h
index 968b37f7a9f..1a856b15226 100644
--- a/arch/powerpc/include/asm/elf.h
+++ b/arch/powerpc/include/asm/elf.h
@@ -179,7 +179,8 @@ typedef elf_fpreg_t elf_vsrreghalf_t32[ELF_NVSRHALFREG];
the loader. We need to make sure that it is out of the way of the program
that it will "exec", and that there is sufficient room for the brk. */
-#define ELF_ET_DYN_BASE (0x20000000)
+extern unsigned long randomize_et_dyn(unsigned long base);
+#define ELF_ET_DYN_BASE (randomize_et_dyn(0x20000000))
/*
* Our registers are always unsigned longs, whether we're a 32 bit
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 30b149ce759..eac06494878 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1170,3 +1170,13 @@ unsigned long arch_randomize_brk(struct mm_struct *mm)
return ret;
}
+
+unsigned long randomize_et_dyn(unsigned long base)
+{
+ unsigned long ret = PAGE_ALIGN(base + brk_rnd());
+
+ if (ret < base)
+ return base;
+
+ return ret;
+}