diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm/Kconfig | 15 | ||||
| -rw-r--r-- | arch/arm/Makefile | 12 | ||||
| -rw-r--r-- | arch/arm/boot/compressed/Makefile | 1 | ||||
| -rw-r--r-- | arch/arm/include/asm/stackprotector.h | 12 | ||||
| -rw-r--r-- | arch/arm/include/asm/thread_info.h | 3 | ||||
| -rw-r--r-- | arch/arm/kernel/asm-offsets.c | 4 | ||||
| -rw-r--r-- | arch/arm/kernel/process.c | 6 |
7 files changed, 50 insertions, 3 deletions
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 91be74d8df65..5c0305585a0a 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1810,6 +1810,21 @@ config XEN help Say Y if you want to run Linux in a Virtual Machine on Xen on ARM. +config STACKPROTECTOR_PER_TASK + bool "Use a unique stack canary value for each task" + depends on GCC_PLUGINS && STACKPROTECTOR && SMP && !XIP_DEFLATED_DATA + select GCC_PLUGIN_ARM_SSP_PER_TASK + default y + help + Due to the fact that GCC uses an ordinary symbol reference from + which to load the value of the stack canary, this value can only + change at reboot time on SMP systems, and all tasks running in the + kernel's address space are forced to use the same canary value for + the entire duration that the system is up. + + Enable this option to switch to a different method that uses a + different canary value for each task. + endmenu menu "Boot options" diff --git a/arch/arm/Makefile b/arch/arm/Makefile index 05a91d8b89f3..0436002d5091 100644 --- a/arch/arm/Makefile +++ b/arch/arm/Makefile @@ -303,6 +303,18 @@ else KBUILD_IMAGE := $(boot)/zImage endif +ifeq ($(CONFIG_STACKPROTECTOR_PER_TASK),y) +prepare: stack_protector_prepare +stack_protector_prepare: prepare0 + $(eval KBUILD_CFLAGS += \ + -fplugin-arg-arm_ssp_per_task_plugin-tso=$(shell \ + awk '{if ($$2 == "THREAD_SZ_ORDER") print $$3;}'\ + include/generated/asm-offsets.h) \ + -fplugin-arg-arm_ssp_per_task_plugin-offset=$(shell \ + awk '{if ($$2 == "TI_STACK_CANARY") print $$3;}'\ + include/generated/asm-offsets.h)) +endif + all: $(notdir $(KBUILD_IMAGE)) diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile index 1f5a5ffe7fcf..01bf2585a0fa 100644 --- a/arch/arm/boot/compressed/Makefile +++ b/arch/arm/boot/compressed/Makefile @@ -101,6 +101,7 @@ clean-files += piggy_data lib1funcs.S ashldi3.S bswapsdi2.S \ $(libfdt) $(libfdt_hdrs) hyp-stub.S KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING +KBUILD_CFLAGS += $(DISABLE_ARM_SSP_PER_TASK_PLUGIN) ifeq ($(CONFIG_FUNCTION_TRACER),y) ORIG_CFLAGS := $(KBUILD_CFLAGS) diff --git a/arch/arm/include/asm/stackprotector.h b/arch/arm/include/asm/stackprotector.h index ef5f7b69443e..72a20c3a0a90 100644 --- a/arch/arm/include/asm/stackprotector.h +++ b/arch/arm/include/asm/stackprotector.h @@ -6,8 +6,10 @@ * the stack frame and verifying that it hasn't been overwritten when * returning from the function. The pattern is called stack canary * and gcc expects it to be defined by a global variable called - * "__stack_chk_guard" on ARM. This unfortunately means that on SMP - * we cannot have a different canary value per task. + * "__stack_chk_guard" on ARM. This prevents SMP systems from using a + * different value for each task unless we enable a GCC plugin that + * replaces these symbol references with references to each task's own + * value. */ #ifndef _ASM_STACKPROTECTOR_H @@ -16,6 +18,8 @@ #include <linux/random.h> #include <linux/version.h> +#include <asm/thread_info.h> + extern unsigned long __stack_chk_guard; /* @@ -33,7 +37,11 @@ static __always_inline void boot_init_stack_canary(void) canary ^= LINUX_VERSION_CODE; current->stack_canary = canary; +#ifndef CONFIG_STACKPROTECTOR_PER_TASK __stack_chk_guard = current->stack_canary; +#else + current_thread_info()->stack_canary = current->stack_canary; +#endif } #endif /* _ASM_STACKPROTECTOR_H */ diff --git a/arch/arm/include/asm/thread_info.h b/arch/arm/include/asm/thread_info.h index 8f55dc520a3e..286eb61c632b 100644 --- a/arch/arm/include/asm/thread_info.h +++ b/arch/arm/include/asm/thread_info.h @@ -53,6 +53,9 @@ struct thread_info { struct task_struct *task; /* main task structure */ __u32 cpu; /* cpu */ __u32 cpu_domain; /* cpu domain */ +#ifdef CONFIG_STACKPROTECTOR_PER_TASK + unsigned long stack_canary; +#endif struct cpu_context_save cpu_context; /* cpu context */ __u32 syscall; /* syscall number */ __u8 used_cp[16]; /* thread used copro */ diff --git a/arch/arm/kernel/asm-offsets.c b/arch/arm/kernel/asm-offsets.c index 3968d6c22455..28b27104ac0c 100644 --- a/arch/arm/kernel/asm-offsets.c +++ b/arch/arm/kernel/asm-offsets.c @@ -79,6 +79,10 @@ int main(void) #ifdef CONFIG_CRUNCH DEFINE(TI_CRUNCH_STATE, offsetof(struct thread_info, crunchstate)); #endif +#ifdef CONFIG_STACKPROTECTOR_PER_TASK + DEFINE(TI_STACK_CANARY, offsetof(struct thread_info, stack_canary)); +#endif + DEFINE(THREAD_SZ_ORDER, THREAD_SIZE_ORDER); BLANK(); DEFINE(S_R0, offsetof(struct pt_regs, ARM_r0)); DEFINE(S_R1, offsetof(struct pt_regs, ARM_r1)); diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c index 82ab015bf42b..16601d1442d1 100644 --- a/arch/arm/kernel/process.c +++ b/arch/arm/kernel/process.c @@ -39,7 +39,7 @@ #include <asm/tls.h> #include <asm/vdso.h> -#ifdef CONFIG_STACKPROTECTOR +#if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_STACKPROTECTOR_PER_TASK) #include <linux/stackprotector.h> unsigned long __stack_chk_guard __read_mostly; EXPORT_SYMBOL(__stack_chk_guard); @@ -267,6 +267,10 @@ copy_thread(unsigned long clone_flags, unsigned long stack_start, thread_notify(THREAD_NOTIFY_COPY, thread); +#ifdef CONFIG_STACKPROTECTOR_PER_TASK + thread->stack_canary = p->stack_canary; +#endif + return 0; } |