[PATCH] arm64: Clear the stack
From: Laura Abbott <hidden>
Date: 2018-06-29 19:06:04
Also in:
lkml
Subsystem:
arm64 port (aarch64 architecture), extensible firmware interface (efi), gcc plugins, kernel build + files below scripts/ (unless maintained elsewhere), kernel virtual machine for arm64 (kvm/arm64), the rest · Maintainers:
Catalin Marinas, Will Deacon, Ard Biesheuvel, Kees Cook, Nathan Chancellor, Nicolas Schier, Marc Zyngier, Oliver Upton, Linus Torvalds
Implementation of stackleak based heavily on the x86 version Signed-off-by: Laura Abbott <redacted> --- Changes since last time: - Minor name change in entry.S - Converted to use the generic interfaces so there's minimal additions. - Added the fast syscall path. - Addition of on_thread_stack and current_top_of_stack - Disable stackleak on hyp per suggestion - Added a define for check_alloca. I'm still not sure about keeping it since the x86 version got reworked? I've mostly kept this as one patch with a minimal commit text. I can split it up and elaborate more before final merging. --- arch/arm64/Kconfig | 1 + arch/arm64/include/asm/processor.h | 9 +++++++++ arch/arm64/kernel/entry.S | 7 +++++++ arch/arm64/kernel/process.c | 16 ++++++++++++++++ arch/arm64/kvm/hyp/Makefile | 3 ++- drivers/firmware/efi/libstub/Makefile | 3 ++- include/linux/stackleak.h | 1 + scripts/Makefile.gcc-plugins | 5 ++++- 8 files changed, 42 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index eb2cf4938f6d..b0221db95dc9 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig@@ -92,6 +92,7 @@ config ARM64 select HAVE_ARCH_MMAP_RND_BITS select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT select HAVE_ARCH_SECCOMP_FILTER + select HAVE_ARCH_STACKLEAK select HAVE_ARCH_THREAD_STRUCT_WHITELIST select HAVE_ARCH_TRACEHOOK select HAVE_ARCH_TRANSPARENT_HUGEPAGE
diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
index 767598932549..73914fd7e142 100644
--- a/arch/arm64/include/asm/processor.h
+++ b/arch/arm64/include/asm/processor.h@@ -248,5 +248,14 @@ void cpu_clear_disr(const struct arm64_cpu_capabilities *__unused); #define SVE_SET_VL(arg) sve_set_current_vl(arg) #define SVE_GET_VL() sve_get_current_vl() +/* + * For stackleak + * + * These need to be macros because otherwise we get stuck in a nightmare + * of header definitions for the use of task_stack_page. + */ +#define current_top_of_stack() (task_stack_page(current) + THREAD_SIZE) +#define on_thread_stack() (on_task_stack(current, current_stack_pointer)) + #endif /* __ASSEMBLY__ */ #endif /* __ASM_PROCESSOR_H */
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index ec2ee720e33e..31c9da7d401e 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S@@ -401,6 +401,11 @@ tsk .req x28 // current thread_info .text + .macro stackleak_erase +#ifdef CONFIG_GCC_PLUGIN_STACKLEAK + bl stackleak_erase_kstack +#endif + .endm /* * Exception vectors. */
@@ -880,6 +885,7 @@ ret_fast_syscall: and x2, x1, #_TIF_WORK_MASK cbnz x2, work_pending enable_step_tsk x1, x2 + stackleak_erase kernel_exit 0 ret_fast_syscall_trace: enable_daif
@@ -906,6 +912,7 @@ ret_to_user: cbnz x2, work_pending finish_ret_to_user: enable_step_tsk x1, x2 + stackleak_erase kernel_exit 0 ENDPROC(ret_to_user)
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index f08a2ed9db0d..9f0f135f8b66 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c@@ -493,3 +493,19 @@ void arch_setup_new_exec(void) { current->mm->context.flags = is_compat_task() ? MMCF_AARCH32 : 0; } + +#ifdef CONFIG_GCC_PLUGIN_STACKLEAK +#define MIN_STACK_LEFT 256 + +void __used stackleak_check_alloca(unsigned long size) +{ + unsigned long sp, stack_left; + + sp = current_stack_pointer; + + stack_left = sp & (THREAD_SIZE - 1); + BUG_ON(stack_left < MIN_STACK_LEFT || + size >= stack_left - MIN_STACK_LEFT); +} +EXPORT_SYMBOL(stackleak_check_alloca); +#endif
diff --git a/arch/arm64/kvm/hyp/Makefile b/arch/arm64/kvm/hyp/Makefile
index 4313f7475333..2fabc2dc1966 100644
--- a/arch/arm64/kvm/hyp/Makefile
+++ b/arch/arm64/kvm/hyp/Makefile@@ -3,7 +3,8 @@ # Makefile for Kernel-based Virtual Machine module, HYP part # -ccflags-y += -fno-stack-protector -DDISABLE_BRANCH_PROFILING +ccflags-y += -fno-stack-protector -DDISABLE_BRANCH_PROFILING \ + $(DISABLE_STACKLEAK_PLUGIN) KVM=../../../../virt/kvm
diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index a34e9290a699..25dd2a14560d 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile@@ -20,7 +20,8 @@ cflags-$(CONFIG_EFI_ARMSTUB) += -I$(srctree)/scripts/dtc/libfdt KBUILD_CFLAGS := $(cflags-y) -DDISABLE_BRANCH_PROFILING \ -D__NO_FORTIFY \ $(call cc-option,-ffreestanding) \ - $(call cc-option,-fno-stack-protector) + $(call cc-option,-fno-stack-protector) \ + $(DISABLE_STACKLEAK_PLUGIN) GCOV_PROFILE := n KASAN_SANITIZE := n
diff --git a/include/linux/stackleak.h b/include/linux/stackleak.h
index e2da99b3a191..00d62b302efb 100644
--- a/include/linux/stackleak.h
+++ b/include/linux/stackleak.h@@ -5,6 +5,7 @@ #include <linux/sched.h> #include <linux/sched/task_stack.h> +#include <asm/stacktrace.h> /* * Check that the poison value points to the unused hole in the * virtual memory map for your platform.
diff --git a/scripts/Makefile.gcc-plugins b/scripts/Makefile.gcc-plugins
index a535742a1c06..972ce4ca7f6a 100644
--- a/scripts/Makefile.gcc-plugins
+++ b/scripts/Makefile.gcc-plugins@@ -37,11 +37,14 @@ ifdef CONFIG_GCC_PLUGINS gcc-plugin-$(CONFIG_GCC_PLUGIN_STACKLEAK) += stackleak_plugin.so gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK) += -DSTACKLEAK_PLUGIN -fplugin-arg-stackleak_plugin-track-min-size=$(CONFIG_STACKLEAK_TRACK_MIN_SIZE) + ifdef CONFIG_GCC_PLUGIN_STACKLEAK + DISABLE_STACKLEAK_PLUGIN += -fplugin-arg-stackleak_plugin-disable + endif GCC_PLUGINS_CFLAGS := $(strip $(addprefix -fplugin=$(objtree)/scripts/gcc-plugins/, $(gcc-plugin-y)) $(gcc-plugin-cflags-y)) export PLUGINCC GCC_PLUGINS_CFLAGS GCC_PLUGIN GCC_PLUGIN_SUBDIR - export SANCOV_PLUGIN DISABLE_LATENT_ENTROPY_PLUGIN + export SANCOV_PLUGIN DISABLE_LATENT_ENTROPY_PLUGIN DISABLE_STACKLEAK_PLUGIN ifneq ($(PLUGINCC),) # SANCOV_PLUGIN can be only in CFLAGS_KCOV because avoid duplication.
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2.17.1