fs: binfmt_elf: create Kconfig variable for PIE randomization
Randomization of PIE load address is hard coded in binfmt_elf.c for X86
and ARM. Create a new Kconfig variable
(CONFIG_ARCH_BINFMT_ELF_RANDOMIZE_PIE) for this and use it instead. Thus
architecture specific policy is pushed out of the generic binfmt_elf.c and
into the architecture Kconfig files.
X86 and ARM Kconfigs are modified to select the new variable so there is
no change in behavior. A follow on patch will select it for MIPS too.
Signed-off-by: David Daney <david.daney@cavium.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 9d66dfc..98a6459 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -16,6 +16,7 @@
select HAVE_FTRACE_MCOUNT_RECORD if (!XIP_KERNEL)
select HAVE_DYNAMIC_FTRACE if (!XIP_KERNEL)
select HAVE_FUNCTION_GRAPH_TRACER if (!THUMB2_KERNEL)
+ select ARCH_BINFMT_ELF_RANDOMIZE_PIE
select HAVE_GENERIC_DMA_COHERENT
select HAVE_KERNEL_GZIP
select HAVE_KERNEL_LZO
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 1d2a69d..d6ddc0b 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -62,6 +62,7 @@
select ANON_INODES
select HAVE_ARCH_KMEMCHECK
select HAVE_USER_RETURN_NOTIFIER
+ select ARCH_BINFMT_ELF_RANDOMIZE_PIE
select HAVE_ARCH_JUMP_LABEL
select HAVE_TEXT_POKE_SMP
select HAVE_GENERIC_HARDIRQS
diff --git a/fs/Kconfig.binfmt b/fs/Kconfig.binfmt
index 79e2ca7..e95d1b6 100644
--- a/fs/Kconfig.binfmt
+++ b/fs/Kconfig.binfmt
@@ -27,6 +27,9 @@
bool
depends on COMPAT && BINFMT_ELF
+config ARCH_BINFMT_ELF_RANDOMIZE_PIE
+ bool
+
config BINFMT_ELF_FDPIC
bool "Kernel support for FDPIC ELF binaries"
default y
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 21ac5ee..bcb884e 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -794,7 +794,7 @@
* default mmap base, as well as whatever program they
* might try to exec. This is because the brk will
* follow the loader, and is not movable. */
-#if defined(CONFIG_X86) || defined(CONFIG_ARM)
+#ifdef CONFIG_ARCH_BINFMT_ELF_RANDOMIZE_PIE
/* Memory randomization might have been switched off
* in runtime via sysctl.
* If that is the case, retain the original non-zero