From 0a1213fa7432778b71a1c0166bf56660a3aab030 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Wed, 12 Dec 2018 13:08:44 +0100 Subject: arm64: enable per-task stack canaries This enables the use of per-task stack canary values if GCC has support for emitting the stack canary reference relative to the value of sp_el0, which holds the task struct pointer in the arm64 kernel. The $(eval) extends KBUILD_CFLAGS at the moment the make rule is applied, which means asm-offsets.o (which we rely on for the offset value) is built without the arguments, and everything built afterwards has the options set. Reviewed-by: Kees Cook Signed-off-by: Ard Biesheuvel Signed-off-by: Will Deacon --- arch/arm64/kernel/asm-offsets.c | 3 +++ arch/arm64/kernel/process.c | 2 +- 2 files changed, 4 insertions(+), 1 deletion(-) (limited to 'arch/arm64/kernel') diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c index 323aeb5f2fe6..65b8afc84466 100644 --- a/arch/arm64/kernel/asm-offsets.c +++ b/arch/arm64/kernel/asm-offsets.c @@ -46,6 +46,9 @@ int main(void) DEFINE(TSK_TI_TTBR0, offsetof(struct task_struct, thread_info.ttbr0)); #endif DEFINE(TSK_STACK, offsetof(struct task_struct, stack)); +#ifdef CONFIG_STACKPROTECTOR + DEFINE(TSK_STACK_CANARY, offsetof(struct task_struct, stack_canary)); +#endif BLANK(); DEFINE(THREAD_CPU_CONTEXT, offsetof(struct task_struct, thread.cpu_context)); BLANK(); diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index d9a4c2d6dd8b..8a2d68f04e0d 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -59,7 +59,7 @@ #include #include -#ifdef CONFIG_STACKPROTECTOR +#if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_STACKPROTECTOR_PER_TASK) #include unsigned long __stack_chk_guard __read_mostly; EXPORT_SYMBOL(__stack_chk_guard); -- cgit v1.2.3