Implementation of stackleak based heavily on the x86 version
Signed-off-by: Laura Abbott <[email protected]> --- Since last time: Minor style cleanups. Re-wrote check_alloca to correctly handle all stack types. While doing that, I also realized current_top_of_stack was incorrect so I fixed that as well. --- arch/arm64/Kconfig | 1 + arch/arm64/include/asm/processor.h | 17 ++++++++++++++ arch/arm64/kernel/entry.S | 7 ++++++ arch/arm64/kernel/process.c | 32 +++++++++++++++++++++++++++ arch/arm64/kvm/hyp/Makefile | 3 ++- drivers/firmware/efi/libstub/Makefile | 3 ++- include/linux/stackleak.h | 1 + 7 files changed, 62 insertions(+), 2 deletions(-) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 42c090cf0292..216d36a49ab5 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -96,6 +96,7 @@ 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 a73ae1e49200..4f3062ee22c6 100644 --- a/arch/arm64/include/asm/processor.h +++ b/arch/arm64/include/asm/processor.h @@ -266,5 +266,22 @@ extern void __init minsigstksz_setup(void); #define SVE_SET_VL(arg) sve_set_current_vl(arg) #define SVE_GET_VL() sve_get_current_vl() +/* + * For CONFIG_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() \ +({ \ + unsigned long _low = 0; \ + unsigned long _high = 0; \ + \ + current_stack_type(current, current_stack_pointer, &_low, &_high); \ + _high; \ +}) +#define on_thread_stack() (on_task_stack(current, current_stack_pointer, NULL, NULL)) + #endif /* __ASSEMBLY__ */ #endif /* __ASM_PROCESSOR_H */ diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 28ad8799406f..67d12016063d 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -431,6 +431,11 @@ tsk .req x28 // current thread_info .text + .macro stackleak_erase +#ifdef CONFIG_GCC_PLUGIN_STACKLEAK + bl stackleak_erase +#endif + .endm /* * Exception vectors. */ @@ -910,6 +915,7 @@ 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 @@ -936,6 +942,7 @@ 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 e10bc363f533..904defa36689 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -493,3 +493,35 @@ void arch_setup_new_exec(void) { current->mm->context.flags = is_compat_task() ? MMCF_AARCH32 : 0; } + +#ifdef CONFIG_GCC_PLUGIN_STACKLEAK +void __used stackleak_check_alloca(unsigned long size) +{ + unsigned long stack_left; + enum stack_type type; + unsigned long current_sp = current_stack_pointer; + unsigned long low, high; + + type = current_stack_type(current, current_sp, &low, &high); + BUG_ON(type == STACK_TYPE_UNKNOWN); + + stack_left = current_sp - low; + + if (size >= stack_left) { + /* + * Kernel stack depth overflow is detected, let's report that. + * If CONFIG_VMAP_STACK is enabled, we can safely use BUG(). + * If CONFIG_VMAP_STACK is disabled, BUG() handling can corrupt + * the neighbour memory. CONFIG_SCHED_STACK_END_CHECK calls + * panic() in a similar situation, so let's do the same if that + * option is on. Otherwise just use BUG() and hope for the best. + */ +#if !defined(CONFIG_VMAP_STACK) && defined(CONFIG_SCHED_STACK_END_CHECK) + panic("alloca() over the kernel stack boundary\n"); +#else + BUG(); +#endif + } +} +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 b911b973d328..08420ec6b7c3 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. -- 2.17.1
