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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2018-12-12 15:08:44 +0300
committerWill Deacon <will.deacon@arm.com>2018-12-12 21:45:31 +0300
commit0a1213fa7432778b71a1c0166bf56660a3aab030 (patch)
treeddf7b68d14a504fe97fbdefe00bf8a3296590cc5 /arch/arm64/kernel
parent4ab215061554ae2a4b78744a5dd3b3c6639f16a7 (diff)
downloadlinux-0a1213fa7432778b71a1c0166bf56660a3aab030.tar.xz
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 <keescook@chromium.org> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/arm64/kernel')
-rw-r--r--arch/arm64/kernel/asm-offsets.c3
-rw-r--r--arch/arm64/kernel/process.c2
2 files changed, 4 insertions, 1 deletions
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 <asm/processor.h>
#include <asm/stacktrace.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);