Messages in this thread Patch in this message |  | | From | Arun Chandran <> | Subject | [PATCH v1] Arm64: ASLR: fix text randomization | Date | Tue, 7 Oct 2014 18:10:28 +0530 |
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This is due to incorrect definition of ELF_ET_DYN_BASE. It introduces randomization for text even if user does a "echo 0 > /proc/sys/kernel/randomize_va_space"
Signed-off-by: Arun Chandran <achandran@mvista.com> --- This can be tested using the code below
#include <stdio.h>
int main(int argc, char *argv) { printf("main = %p\n", main); return 0; }
* compile it possition independently aarch64-linux-gnu-gcc -fPIE -pie aslr.c -o aslr
* run it on the target
# ./aslr main = 0x7f87138950 # ./aslr main = 0x7f94a10950 # ./aslr main = 0x7f94fee950 # ./aslr text main = 0x7f8cb72950
# echo 0 > /proc/sys/kernel/randomize_va_space # ./aslr text main = 0x5555555950 # ./aslr main = 0x5555555950 # ./aslr main = 0x5555555950 # ./aslr main = 0x5555555950 --- arch/arm64/Kconfig | 1 + arch/arm64/include/asm/elf.h | 4 ++-- 2 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index fd4e81a..a2eefc9 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1,5 +1,6 @@ config ARM64 def_bool y + select ARCH_BINFMT_ELF_RANDOMIZE_PIE select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE select ARCH_HAS_SG_CHAIN select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h index 01d3aab..1f65be3 100644 --- a/arch/arm64/include/asm/elf.h +++ b/arch/arm64/include/asm/elf.h @@ -126,7 +126,7 @@ typedef struct user_fpsimd_state elf_fpregset_t; * that it will "exec", and that there is sufficient room for the brk. */ extern unsigned long randomize_et_dyn(unsigned long base); -#define ELF_ET_DYN_BASE (randomize_et_dyn(2 * TASK_SIZE_64 / 3)) +#define ELF_ET_DYN_BASE (2 * TASK_SIZE_64 / 3) /* * When the program starts, a1 contains a pointer to a function to be @@ -169,7 +169,7 @@ extern unsigned long arch_randomize_brk(struct mm_struct *mm); #define COMPAT_ELF_PLATFORM ("v8l") #endif -#define COMPAT_ELF_ET_DYN_BASE (randomize_et_dyn(2 * TASK_SIZE_32 / 3)) +#define COMPAT_ELF_ET_DYN_BASE (2 * TASK_SIZE_32 / 3) /* AArch32 registers. */ #define COMPAT_ELF_NGREG 18 -- 1.7.9.5
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