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. Cc: Russell King <linux@xxxxxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx> Cc: x86@xxxxxxxxxx Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx Cc: linux-kernel@xxxxxxxxxxxxxxx Cc: linux-fsdevel@xxxxxxxxxxxxxxx Signed-off-by: David Daney <david.daney@xxxxxxxxxx> --- arch/arm/Kconfig | 1 + arch/x86/Kconfig | 1 + fs/Kconfig.binfmt | 3 +++ fs/binfmt_elf.c | 2 +- 4 files changed, 6 insertions(+), 1 deletions(-) diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 44789ef..3830439 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -30,6 +30,7 @@ config ARM select HAVE_SPARSE_IRQ select GENERIC_IRQ_SHOW select CPU_PM if (SUSPEND || CPU_IDLE) + select ARCH_BINFMT_ELF_RANDOMIZE_PIE help The ARM series is a line of low-power-consumption RISC chip designs licensed by ARM Ltd and targeted at embedded applications and diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index cb9a104..9c3e447 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -75,6 +75,7 @@ config X86 select HAVE_BPF_JIT if (X86_64 && NET) select CLKEVT_I8253 select ARCH_HAVE_NMI_SAFE_CMPXCHG + select ARCH_BINFMT_ELF_RANDOMIZE_PIE config INSTRUCTION_DECODER def_bool (KPROBES || PERF_EVENTS) 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 @@ config COMPAT_BINFMT_ELF 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 @@ static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs) * 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 -- 1.7.2.3
