[PATCH RFC 0/4] stackleak: Support Clang stack depth tracking

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Kees Cook

2 May 2025 2 May '25

7:01 p.m.

Hi,

As part of looking at what GCC plugins could be replaced with Clang implementations, this series uses the recently proposed stack depth tracking callback in Clang[1] to implement the stackleak feature.

-Kees

[1] https://github.com/llvm/llvm-project/pull/138323

Kees Cook (4): stackleak: Rename CONFIG_GCC_PLUGIN_STACKLEAK to CONFIG_STACKLEAK stackleak: Rename stackleak_track_stack to __sanitizer_cov_stack_depth stackleak: Split STACKLEAK_CFLAGS from GCC_PLUGINS_CFLAGS stackleak: Support Clang stack depth tracking

-- 2.34.1

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Kees Cook

2 May 2 May

7:01 p.m.

New subject: [PATCH RFC 1/4] stackleak: Rename CONFIG_GCC_PLUGIN_STACKLEAK to CONFIG_STACKLEAK

In preparation for adding Clang sanitizer coverage stack depth tracking that can support stack depth callbacks, remove "GCC_PLUGIN" from "CONFIG_GCC_PLUGIN_STACKLEAK" and remove "PLUGIN" from "DISABLE_STACKLEAK_PLUGIN". Rearrange the Kconfig to have a top-level CONFIG_STACKLEAK that will depend on either GCC plugins or Clang soon.

While here, also split "prev_lowest_stack" into CONFIG_STACKLEAK_METRICS, since that's the only place it is referenced from.

Signed-off-by: Kees Cook kees@kernel.org --- Cc: Arnd Bergmann arnd@arndb.de Cc: x86@kernel.org Cc: "Gustavo A. R. Silva" gustavoars@kernel.org Cc: linux-doc@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: kvmarm@lists.linux.dev Cc: linux-riscv@lists.infradead.org Cc: linux-s390@vger.kernel.org Cc: linux-efi@vger.kernel.org Cc: linux-hardening@vger.kernel.org Cc: linux-kbuild@vger.kernel.org Cc: linux-security-module@vger.kernel.org Cc: linux-kselftest@vger.kernel.org --- Documentation/admin-guide/sysctl/kernel.rst | 2 +- Documentation/security/self-protection.rst | 2 +- arch/arm/boot/compressed/Makefile | 2 +- arch/arm/kernel/entry-common.S | 2 +- arch/arm64/kernel/entry.S | 2 +- arch/arm64/kernel/pi/Makefile | 2 +- arch/arm64/kvm/hyp/nvhe/Makefile | 2 +- arch/riscv/kernel/entry.S | 2 +- arch/riscv/kernel/pi/Makefile | 2 +- arch/riscv/purgatory/Makefile | 2 +- arch/s390/kernel/entry.S | 2 +- arch/x86/entry/calling.h | 4 ++-- arch/x86/purgatory/Makefile | 2 +- drivers/firmware/efi/libstub/Makefile | 6 +++--- drivers/misc/lkdtm/stackleak.c | 8 ++++---- include/linux/sched.h | 4 +++- include/linux/stackleak.h | 4 ++-- kernel/Makefile | 4 ++-- lib/Makefile | 2 +- scripts/Makefile.gcc-plugins | 4 ++-- security/Kconfig.hardening | 18 +++++++++++------- tools/testing/selftests/lkdtm/config | 2 +- 22 files changed, 43 insertions(+), 37 deletions(-)

diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst index dd49a89a62d3..c94475661a80 100644 --- a/Documentation/admin-guide/sysctl/kernel.rst +++ b/Documentation/admin-guide/sysctl/kernel.rst @@ -1465,7 +1465,7 @@ stack_erasing =============

This parameter can be used to control kernel stack erasing at the end -of syscalls for kernels built with ``CONFIG_GCC_PLUGIN_STACKLEAK``. +of syscalls for kernels built with ``CONFIG_STACKLEAK``.

That erasing reduces the information which kernel stack leak bugs can reveal and blocks some uninitialized stack variable attacks. diff --git a/Documentation/security/self-protection.rst b/Documentation/security/self-protection.rst index 910668e665cb..67a266d38172 100644 --- a/Documentation/security/self-protection.rst +++ b/Documentation/security/self-protection.rst @@ -303,7 +303,7 @@ Memory poisoning

When releasing memory, it is best to poison the contents, to avoid reuse attacks that rely on the old contents of memory. E.g., clear stack on a -syscall return (``CONFIG_GCC_PLUGIN_STACKLEAK``), wipe heap memory on a +syscall return (``CONFIG_STACKLEAK``), wipe heap memory on a free. This frustrates many uninitialized variable attacks, stack content exposures, heap content exposures, and use-after-free attacks.

diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile index 945b5975fce2..2da39e41e5c0 100644 --- a/arch/arm/boot/compressed/Makefile +++ b/arch/arm/boot/compressed/Makefile @@ -9,7 +9,7 @@ OBJS =

HEAD = head.o OBJS += misc.o decompress.o -CFLAGS_decompress.o += $(DISABLE_STACKLEAK_PLUGIN) +CFLAGS_decompress.o += $(DISABLE_STACKLEAK) ifeq ($(CONFIG_DEBUG_UNCOMPRESS),y) OBJS += debug.o AFLAGS_head.o += -DDEBUG diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S index f379c852dcb7..9921898d29a1 100644 --- a/arch/arm/kernel/entry-common.S +++ b/arch/arm/kernel/entry-common.S @@ -119,7 +119,7 @@ no_work_pending:

ct_user_enter save = 0

-#ifdef CONFIG_GCC_PLUGIN_STACKLEAK +#ifdef CONFIG_STACKLEAK bl stackleak_erase_on_task_stack #endif restore_user_regs fast = 0, offset = 0 diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 5ae2a34b50bd..c5456ff920d3 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -614,7 +614,7 @@ SYM_CODE_END(ret_to_kernel) SYM_CODE_START_LOCAL(ret_to_user) ldr x19, [tsk, #TSK_TI_FLAGS] // re-check for single-step enable_step_tsk x19, x2 -#ifdef CONFIG_GCC_PLUGIN_STACKLEAK +#ifdef CONFIG_STACKLEAK bl stackleak_erase_on_task_stack #endif kernel_exit 0 diff --git a/arch/arm64/kernel/pi/Makefile b/arch/arm64/kernel/pi/Makefile index 4d11a8c29181..77159298f3c6 100644 --- a/arch/arm64/kernel/pi/Makefile +++ b/arch/arm64/kernel/pi/Makefile @@ -2,7 +2,7 @@ # Copyright 2022 Google LLC

KBUILD_CFLAGS := $(subst $(CC_FLAGS_FTRACE),,$(KBUILD_CFLAGS)) -fpie \ - -Os -DDISABLE_BRANCH_PROFILING $(DISABLE_STACKLEAK_PLUGIN) \ + -Os -DDISABLE_BRANCH_PROFILING $(DISABLE_STACKLEAK) \ $(DISABLE_LATENT_ENTROPY_PLUGIN) \ $(call cc-option,-mbranch-protection=none) \ -I$(srctree)/scripts/dtc/libfdt -fno-stack-protector \ diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile index b43426a493df..4e00a2a8ad0c 100644 --- a/arch/arm64/kvm/hyp/nvhe/Makefile +++ b/arch/arm64/kvm/hyp/nvhe/Makefile @@ -12,7 +12,7 @@ asflags-y := -D__KVM_NVHE_HYPERVISOR__ -D__DISABLE_EXPORTS ccflags-y := -D__KVM_NVHE_HYPERVISOR__ -D__DISABLE_EXPORTS -D__DISABLE_TRACE_MMIO__ ccflags-y += -fno-stack-protector \ -DDISABLE_BRANCH_PROFILING \ - $(DISABLE_STACKLEAK_PLUGIN) + $(DISABLE_STACKLEAK)

hostprogs := gen-hyprel HOST_EXTRACFLAGS += -I$(objtree)/include diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S index 33a5a9f2a0d4..d6e9903817f7 100644 --- a/arch/riscv/kernel/entry.S +++ b/arch/riscv/kernel/entry.S @@ -220,7 +220,7 @@ SYM_CODE_START_NOALIGN(ret_from_exception) #endif bnez s0, 1f

-#ifdef CONFIG_GCC_PLUGIN_STACKLEAK +#ifdef CONFIG_STACKLEAK call stackleak_erase_on_task_stack #endif

diff --git a/arch/riscv/kernel/pi/Makefile b/arch/riscv/kernel/pi/Makefile index 81d69d45c06c..40238ed13ea1 100644 --- a/arch/riscv/kernel/pi/Makefile +++ b/arch/riscv/kernel/pi/Makefile @@ -2,7 +2,7 @@ # This file was copied from arm64/kernel/pi/Makefile.

KBUILD_CFLAGS := $(subst $(CC_FLAGS_FTRACE),,$(KBUILD_CFLAGS)) -fpie \ - -Os -DDISABLE_BRANCH_PROFILING $(DISABLE_STACKLEAK_PLUGIN) \ + -Os -DDISABLE_BRANCH_PROFILING $(DISABLE_STACKLEAK) \ $(call cc-option,-mbranch-protection=none) \ -I$(srctree)/scripts/dtc/libfdt -fno-stack-protector \ -include $(srctree)/include/linux/hidden.h \ diff --git a/arch/riscv/purgatory/Makefile b/arch/riscv/purgatory/Makefile index fb9c917c9b45..af8fa4aded5c 100644 --- a/arch/riscv/purgatory/Makefile +++ b/arch/riscv/purgatory/Makefile @@ -53,7 +53,7 @@ targets += purgatory.ro purgatory.chk

PURGATORY_CFLAGS_REMOVE := -mcmodel=kernel PURGATORY_CFLAGS := -mcmodel=medany -ffreestanding -fno-zero-initialized-in-bss -PURGATORY_CFLAGS += $(DISABLE_STACKLEAK_PLUGIN) -DDISABLE_BRANCH_PROFILING +PURGATORY_CFLAGS += $(DISABLE_STACKLEAK) -DDISABLE_BRANCH_PROFILING PURGATORY_CFLAGS += -fno-stack-protector -g0

# Default KBUILD_CFLAGS can have -pg option set when FTRACE is enabled. That diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S index dd291c9ad6a6..6b43318dc0cc 100644 --- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -124,7 +124,7 @@ _LPP_OFFSET = __LC_LPP #endif

.macro STACKLEAK_ERASE -#ifdef CONFIG_GCC_PLUGIN_STACKLEAK +#ifdef CONFIG_STACKLEAK brasl %r14,stackleak_erase_on_task_stack #endif .endm diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h index d83236b96f22..790e63df94a2 100644 --- a/arch/x86/entry/calling.h +++ b/arch/x86/entry/calling.h @@ -369,7 +369,7 @@ For 32-bit we have the following conventions - kernel is built with .endm

.macro STACKLEAK_ERASE_NOCLOBBER -#ifdef CONFIG_GCC_PLUGIN_STACKLEAK +#ifdef CONFIG_STACKLEAK PUSH_AND_CLEAR_REGS call stackleak_erase POP_REGS @@ -388,7 +388,7 @@ For 32-bit we have the following conventions - kernel is built with #endif /* !CONFIG_X86_64 */

.macro STACKLEAK_ERASE -#ifdef CONFIG_GCC_PLUGIN_STACKLEAK +#ifdef CONFIG_STACKLEAK call stackleak_erase #endif .endm diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile index ebdfd7b84feb..5450d5f7fd88 100644 --- a/arch/x86/purgatory/Makefile +++ b/arch/x86/purgatory/Makefile @@ -35,7 +35,7 @@ targets += purgatory.ro purgatory.chk PURGATORY_CFLAGS_REMOVE := -mcmodel=kernel PURGATORY_CFLAGS := -mcmodel=small -ffreestanding -fno-zero-initialized-in-bss -g0 PURGATORY_CFLAGS += -fpic -fvisibility=hidden -PURGATORY_CFLAGS += $(DISABLE_STACKLEAK_PLUGIN) -DDISABLE_BRANCH_PROFILING +PURGATORY_CFLAGS += $(DISABLE_STACKLEAK) -DDISABLE_BRANCH_PROFILING PURGATORY_CFLAGS += -fno-stack-protector

# Default KBUILD_CFLAGS can have -pg option set when FTRACE is enabled. That diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile index d23a1b9fed75..1cfdde43da02 100644 --- a/drivers/firmware/efi/libstub/Makefile +++ b/drivers/firmware/efi/libstub/Makefile @@ -22,15 +22,15 @@ cflags-$(CONFIG_X86) += -m$(BITS) -D__KERNEL__ -std=gnu11 \

# arm64 uses the full KBUILD_CFLAGS so it's necessary to explicitly # disable the stackleak plugin -cflags-$(CONFIG_ARM64) += -fpie $(DISABLE_STACKLEAK_PLUGIN) \ +cflags-$(CONFIG_ARM64) += -fpie $(DISABLE_STACKLEAK) \ -fno-unwind-tables -fno-asynchronous-unwind-tables cflags-$(CONFIG_ARM) += -DEFI_HAVE_STRLEN -DEFI_HAVE_STRNLEN \ -DEFI_HAVE_MEMCHR -DEFI_HAVE_STRRCHR \ -DEFI_HAVE_STRCMP -fno-builtin -fpic \ $(call cc-option,-mno-single-pic-base) \ - $(DISABLE_STACKLEAK_PLUGIN) + $(DISABLE_STACKLEAK) cflags-$(CONFIG_RISCV) += -fpic -DNO_ALTERNATIVE -mno-relax \ - $(DISABLE_STACKLEAK_PLUGIN) + $(DISABLE_STACKLEAK) cflags-$(CONFIG_LOONGARCH) += -fpie

cflags-$(CONFIG_EFI_PARAMS_FROM_FDT) += -I$(srctree)/scripts/dtc/libfdt diff --git a/drivers/misc/lkdtm/stackleak.c b/drivers/misc/lkdtm/stackleak.c index f1d022160913..ab8c690a039a 100644 --- a/drivers/misc/lkdtm/stackleak.c +++ b/drivers/misc/lkdtm/stackleak.c @@ -11,7 +11,7 @@ #include "lkdtm.h" #include <linux/stackleak.h>

-#if defined(CONFIG_GCC_PLUGIN_STACKLEAK) +#if defined(CONFIG_STACKLEAK) /* * Check that stackleak tracks the lowest stack pointer and erases the stack * below this as expected. @@ -129,16 +129,16 @@ static void lkdtm_STACKLEAK_ERASING(void) check_stackleak_irqoff(); local_irq_restore(flags); } -#else /* defined(CONFIG_GCC_PLUGIN_STACKLEAK) */ +#else /* defined(CONFIG_STACKLEAK) */ static void lkdtm_STACKLEAK_ERASING(void) { if (IS_ENABLED(CONFIG_HAVE_ARCH_STACKLEAK)) { - pr_err("XFAIL: stackleak is not enabled (CONFIG_GCC_PLUGIN_STACKLEAK=n)\n"); + pr_err("XFAIL: stackleak is not enabled (CONFIG_STACKLEAK=n)\n"); } else { pr_err("XFAIL: stackleak is not supported on this arch (HAVE_ARCH_STACKLEAK=n)\n"); } } -#endif /* defined(CONFIG_GCC_PLUGIN_STACKLEAK) */ +#endif /* defined(CONFIG_STACKLEAK) */

static struct crashtype crashtypes[] = { CRASHTYPE(STACKLEAK_ERASING), diff --git a/include/linux/sched.h b/include/linux/sched.h index f96ac1982893..f323a4d9f0ef 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1599,8 +1599,10 @@ struct task_struct { /* Used by BPF for per-TASK xdp storage */ struct bpf_net_context *bpf_net_context;

-#ifdef CONFIG_GCC_PLUGIN_STACKLEAK +#ifdef CONFIG_STACKLEAK unsigned long lowest_stack; +#endif +#ifdef CONFIG_STACKLEAK_METRICS unsigned long prev_lowest_stack; #endif

diff --git a/include/linux/stackleak.h b/include/linux/stackleak.h index 3be2cb564710..71e8242fd8f2 100644 --- a/include/linux/stackleak.h +++ b/include/linux/stackleak.h @@ -12,7 +12,7 @@ #define STACKLEAK_POISON -0xBEEF #define STACKLEAK_SEARCH_DEPTH 128

-#ifdef CONFIG_GCC_PLUGIN_STACKLEAK +#ifdef CONFIG_STACKLEAK #include <asm/stacktrace.h> #include <linux/linkage.h>

@@ -82,7 +82,7 @@ asmlinkage void noinstr stackleak_erase_on_task_stack(void); asmlinkage void noinstr stackleak_erase_off_task_stack(void); void __no_caller_saved_registers noinstr stackleak_track_stack(void);

-#else /* !CONFIG_GCC_PLUGIN_STACKLEAK */ +#else /* !CONFIG_STACKLEAK */ static inline void stackleak_task_init(struct task_struct *t) { } #endif

diff --git a/kernel/Makefile b/kernel/Makefile index 434929de17ef..79583e3501b4 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -137,8 +137,8 @@ obj-$(CONFIG_WATCH_QUEUE) += watch_queue.o obj-$(CONFIG_RESOURCE_KUNIT_TEST) += resource_kunit.o obj-$(CONFIG_SYSCTL_KUNIT_TEST) += sysctl-test.o

-CFLAGS_stackleak.o += $(DISABLE_STACKLEAK_PLUGIN) -obj-$(CONFIG_GCC_PLUGIN_STACKLEAK) += stackleak.o +CFLAGS_stackleak.o += $(DISABLE_STACKLEAK) +obj-$(CONFIG_STACKLEAK) += stackleak.o KASAN_SANITIZE_stackleak.o := n KCSAN_SANITIZE_stackleak.o := n KCOV_INSTRUMENT_stackleak.o := n diff --git a/lib/Makefile b/lib/Makefile index f07b24ce1b3f..720c4846d255 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -338,7 +338,7 @@ obj-$(CONFIG_UBSAN) += ubsan.o UBSAN_SANITIZE_ubsan.o := n KASAN_SANITIZE_ubsan.o := n KCSAN_SANITIZE_ubsan.o := n -CFLAGS_ubsan.o := -fno-stack-protector $(DISABLE_STACKLEAK_PLUGIN) +CFLAGS_ubsan.o := -fno-stack-protector $(DISABLE_STACKLEAK)

obj-$(CONFIG_SBITMAP) += sbitmap.o

diff --git a/scripts/Makefile.gcc-plugins b/scripts/Makefile.gcc-plugins index e4deaf5fa571..e3ed92e20d16 100644 --- a/scripts/Makefile.gcc-plugins +++ b/scripts/Makefile.gcc-plugins @@ -32,9 +32,9 @@ gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK) \ gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK_VERBOSE) \ += -fplugin-arg-stackleak_plugin-verbose ifdef CONFIG_GCC_PLUGIN_STACKLEAK - DISABLE_STACKLEAK_PLUGIN += -fplugin-arg-stackleak_plugin-disable + DISABLE_STACKLEAK += -fplugin-arg-stackleak_plugin-disable endif -export DISABLE_STACKLEAK_PLUGIN +export DISABLE_STACKLEAK

gcc-plugin-$(CONFIG_GCC_PLUGIN_ARM_SSP_PER_TASK) += arm_ssp_per_task_plugin.so ifdef CONFIG_GCC_PLUGIN_ARM_SSP_PER_TASK diff --git a/security/Kconfig.hardening b/security/Kconfig.hardening index 3fe9d7b945c4..8aa5c1d4794d 100644 --- a/security/Kconfig.hardening +++ b/security/Kconfig.hardening @@ -158,10 +158,10 @@ config GCC_PLUGIN_STRUCTLEAK_VERBOSE initialized. Since not all existing initializers are detected by the plugin, this can produce false positive warnings.

-config GCC_PLUGIN_STACKLEAK +config STACKLEAK bool "Poison kernel stack before returning from syscalls" - depends on GCC_PLUGINS depends on HAVE_ARCH_STACKLEAK + depends on GCC_PLUGINS help This option makes the kernel erase the kernel stack before returning from system calls. This has the effect of leaving @@ -179,6 +179,10 @@ config GCC_PLUGIN_STACKLEAK are advised to test this feature on your expected workload before deploying it.

+config GCC_PLUGIN_STACKLEAK + def_bool STACKLEAK + depends on GCC_PLUGINS + help This plugin was ported from grsecurity/PaX. More information at: * https://grsecurity.net/ * https://pax.grsecurity.net/ @@ -197,9 +201,9 @@ config STACKLEAK_TRACK_MIN_SIZE int "Minimum stack frame size of functions tracked by STACKLEAK" default 100 range 0 4096 - depends on GCC_PLUGIN_STACKLEAK + depends on STACKLEAK help - The STACKLEAK gcc plugin instruments the kernel code for tracking + The STACKLEAK options instruments the kernel code for tracking the lowest border of the kernel stack (and for some other purposes). It inserts the stackleak_track_stack() call for the functions with a stack frame size greater than or equal to this parameter. @@ -207,7 +211,7 @@ config STACKLEAK_TRACK_MIN_SIZE

config STACKLEAK_METRICS bool "Show STACKLEAK metrics in the /proc file system" - depends on GCC_PLUGIN_STACKLEAK + depends on STACKLEAK depends on PROC_FS help If this is set, STACKLEAK metrics for every task are available in @@ -219,11 +223,11 @@ config STACKLEAK_METRICS

config STACKLEAK_RUNTIME_DISABLE bool "Allow runtime disabling of kernel stack erasing" - depends on GCC_PLUGIN_STACKLEAK + depends on STACKLEAK help This option provides 'stack_erasing' sysctl, which can be used in runtime to control kernel stack erasing for kernels built with - CONFIG_GCC_PLUGIN_STACKLEAK. + CONFIG_STACKLEAK.

config INIT_ON_ALLOC_DEFAULT_ON bool "Enable heap memory zeroing on allocation by default" diff --git a/tools/testing/selftests/lkdtm/config b/tools/testing/selftests/lkdtm/config index 7afe05e8c4d7..b9b1275c07e8 100644 --- a/tools/testing/selftests/lkdtm/config +++ b/tools/testing/selftests/lkdtm/config @@ -2,7 +2,7 @@ CONFIG_LKDTM=y CONFIG_DEBUG_LIST=y CONFIG_SLAB_FREELIST_HARDENED=y CONFIG_FORTIFY_SOURCE=y -CONFIG_GCC_PLUGIN_STACKLEAK=y +CONFIG_STACKLEAK=y CONFIG_HARDENED_USERCOPY=y CONFIG_RANDOMIZE_KSTACK_OFFSET_DEFAULT=y CONFIG_INIT_ON_FREE_DEFAULT_ON=y

-- 2.34.1

Kees Cook

7:01 p.m.

New subject: [PATCH RFC 2/4] stackleak: Rename stackleak_track_stack to __sanitizer_cov_stack_depth

The Clang stack depth tracking implementation has a fixed name for the stack depth tracking callback, "__sanitizer_cov_stack_depth", so rename the GCC plugin function to match.

Signed-off-by: Kees Cook kees@kernel.org --- Cc: Arnd Bergmann arnd@arndb.de Cc: linux-hardening@vger.kernel.org --- include/linux/stackleak.h | 2 +- kernel/stackleak.c | 4 +- scripts/gcc-plugins/stackleak_plugin.c | 52 +++++++++++++------------- security/Kconfig.hardening | 4 +- tools/objtool/check.c | 2 +- 5 files changed, 32 insertions(+), 32 deletions(-)

diff --git a/include/linux/stackleak.h b/include/linux/stackleak.h index 71e8242fd8f2..a669574a3562 100644 --- a/include/linux/stackleak.h +++ b/include/linux/stackleak.h @@ -80,7 +80,7 @@ static inline void stackleak_task_init(struct task_struct *t) asmlinkage void noinstr stackleak_erase(void); asmlinkage void noinstr stackleak_erase_on_task_stack(void); asmlinkage void noinstr stackleak_erase_off_task_stack(void); -void __no_caller_saved_registers noinstr stackleak_track_stack(void); +void __no_caller_saved_registers noinstr __sanitizer_cov_stack_depth(void);

#else /* !CONFIG_STACKLEAK */ static inline void stackleak_task_init(struct task_struct *t) { } diff --git a/kernel/stackleak.c b/kernel/stackleak.c index bb65321761b4..5158468968e2 100644 --- a/kernel/stackleak.c +++ b/kernel/stackleak.c @@ -156,7 +156,7 @@ asmlinkage void noinstr stackleak_erase_off_task_stack(void) __stackleak_erase(false); }

-void __used __no_caller_saved_registers noinstr stackleak_track_stack(void) +void __used __no_caller_saved_registers noinstr __sanitizer_cov_stack_depth(void) { unsigned long sp = current_stack_pointer;

@@ -174,4 +174,4 @@ void __used __no_caller_saved_registers noinstr stackleak_track_stack(void) current->lowest_stack = sp; } } -EXPORT_SYMBOL(stackleak_track_stack); +EXPORT_SYMBOL(__sanitizer_cov_stack_depth); diff --git a/scripts/gcc-plugins/stackleak_plugin.c b/scripts/gcc-plugins/stackleak_plugin.c index d20c47d21ad8..e486488c867d 100644 --- a/scripts/gcc-plugins/stackleak_plugin.c +++ b/scripts/gcc-plugins/stackleak_plugin.c @@ -9,7 +9,7 @@ * any of the gcc libraries * * This gcc plugin is needed for tracking the lowest border of the kernel stack. - * It instruments the kernel code inserting stackleak_track_stack() calls: + * It instruments the kernel code inserting __sanitizer_cov_stack_depth() calls: * - after alloca(); * - for the functions with a stack frame size greater than or equal * to the "track-min-size" plugin parameter. @@ -33,7 +33,7 @@ __visible int plugin_is_GPL_compatible;

static int track_frame_size = -1; static bool build_for_x86 = false; -static const char track_function[] = "stackleak_track_stack"; +static const char track_function[] = "__sanitizer_cov_stack_depth"; static bool disable = false; static bool verbose = false;

@@ -58,7 +58,7 @@ static void add_stack_tracking_gcall(gimple_stmt_iterator *gsi, bool after) cgraph_node_ptr node; basic_block bb;

- /* Insert calling stackleak_track_stack() */ + /* Insert calling __sanitizer_cov_stack_depth() */ stmt = gimple_build_call(track_function_decl, 0); gimple_call = as_a_gcall(stmt); if (after) @@ -120,12 +120,12 @@ static void add_stack_tracking_gasm(gimple_stmt_iterator *gsi, bool after) gcc_assert(build_for_x86);

/* - * Insert calling stackleak_track_stack() in asm: - * asm volatile("call stackleak_track_stack" + * Insert calling __sanitizer_cov_stack_depth() in asm: + * asm volatile("call __sanitizer_cov_stack_depth" * :: "r" (current_stack_pointer)) * Use ASM_CALL_CONSTRAINT trick from arch/x86/include/asm/asm.h. * This constraint is taken into account during gcc shrink-wrapping - * optimization. It is needed to be sure that stackleak_track_stack() + * optimization. It is needed to be sure that __sanitizer_cov_stack_depth() * call is inserted after the prologue of the containing function, * when the stack frame is prepared. */ @@ -137,7 +137,7 @@ static void add_stack_tracking_gasm(gimple_stmt_iterator *gsi, bool after) input = build_tree_list(NULL_TREE, build_const_char_string(2, "r")); input = chainon(NULL_TREE, build_tree_list(input, sp_decl)); vec_safe_push(inputs, input); - asm_call = gimple_build_asm_vec("call stackleak_track_stack", + asm_call = gimple_build_asm_vec("call __sanitizer_cov_stack_depth", inputs, NULL, NULL, NULL); gimple_asm_set_volatile(asm_call, true); if (after) @@ -151,11 +151,11 @@ static void add_stack_tracking(gimple_stmt_iterator *gsi, bool after) { /* * The 'no_caller_saved_registers' attribute is used for - * stackleak_track_stack(). If the compiler supports this attribute for - * the target arch, we can add calling stackleak_track_stack() in asm. + * __sanitizer_cov_stack_depth(). If the compiler supports this attribute for + * the target arch, we can add calling __sanitizer_cov_stack_depth() in asm. * That improves performance: we avoid useless operations with the * caller-saved registers in the functions from which we will remove - * stackleak_track_stack() call during the stackleak_cleanup pass. + * __sanitizer_cov_stack_depth() call during the stackleak_cleanup pass. */ if (lookup_attribute_spec(get_identifier("no_caller_saved_registers"))) add_stack_tracking_gasm(gsi, after); @@ -165,7 +165,7 @@ static void add_stack_tracking(gimple_stmt_iterator *gsi, bool after)

/* * Work with the GIMPLE representation of the code. Insert the - * stackleak_track_stack() call after alloca() and into the beginning + * __sanitizer_cov_stack_depth() call after alloca() and into the beginning * of the function if it is not instrumented. */ static unsigned int stackleak_instrument_execute(void) @@ -205,7 +205,7 @@ static unsigned int stackleak_instrument_execute(void) DECL_NAME_POINTER(current_function_decl)); }

- /* Insert stackleak_track_stack() call after alloca() */ + /* Insert __sanitizer_cov_stack_depth() call after alloca() */ add_stack_tracking(&gsi, true); if (bb == entry_bb) prologue_instrumented = true; @@ -241,7 +241,7 @@ static unsigned int stackleak_instrument_execute(void) return 0; }

- /* Insert stackleak_track_stack() call at the function beginning */ + /* Insert __sanitizer_cov_stack_depth() call at the function beginning */ bb = entry_bb; if (!single_pred_p(bb)) { /* gcc_assert(bb_loop_depth(bb) || @@ -270,15 +270,15 @@ static void remove_stack_tracking_gcall(void) rtx_insn *insn, *next;

/* - * Find stackleak_track_stack() calls. Loop through the chain of insns, + * Find __sanitizer_cov_stack_depth() calls. Loop through the chain of insns, * which is an RTL representation of the code for a function. * * The example of a matching insn: - * (call_insn 8 4 10 2 (call (mem (symbol_ref ("stackleak_track_stack") - * [flags 0x41] <function_decl 0x7f7cd3302a80 stackleak_track_stack>) - * [0 stackleak_track_stack S1 A8]) (0)) 675 {*call} (expr_list - * (symbol_ref ("stackleak_track_stack") [flags 0x41] <function_decl - * 0x7f7cd3302a80 stackleak_track_stack>) (expr_list (0) (nil))) (nil)) + * (call_insn 8 4 10 2 (call (mem (symbol_ref ("__sanitizer_cov_stack_depth") + * [flags 0x41] <function_decl 0x7f7cd3302a80 __sanitizer_cov_stack_depth>) + * [0 __sanitizer_cov_stack_depth S1 A8]) (0)) 675 {*call} (expr_list + * (symbol_ref ("__sanitizer_cov_stack_depth") [flags 0x41] <function_decl + * 0x7f7cd3302a80 __sanitizer_cov_stack_depth>) (expr_list (0) (nil))) (nil)) */ for (insn = get_insns(); insn; insn = next) { rtx body; @@ -318,7 +318,7 @@ static void remove_stack_tracking_gcall(void) if (SYMBOL_REF_DECL(body) != track_function_decl) continue;

- /* Delete the stackleak_track_stack() call */ + /* Delete the __sanitizer_cov_stack_depth() call */ delete_insn_and_edges(insn); #if BUILDING_GCC_VERSION < 8000 if (GET_CODE(next) == NOTE && @@ -340,12 +340,12 @@ static bool remove_stack_tracking_gasm(void) gcc_assert(build_for_x86);

/* - * Find stackleak_track_stack() asm calls. Loop through the chain of + * Find __sanitizer_cov_stack_depth() asm calls. Loop through the chain of * insns, which is an RTL representation of the code for a function. * * The example of a matching insn: * (insn 11 5 12 2 (parallel [ (asm_operands/v - * ("call stackleak_track_stack") ("") 0 + * ("call __sanitizer_cov_stack_depth") ("") 0 * [ (reg/v:DI 7 sp [ current_stack_pointer ]) ] * [ (asm_input:DI ("r")) ] []) * (clobber (reg:CC 17 flags)) ]) -1 (nil)) @@ -375,7 +375,7 @@ static bool remove_stack_tracking_gasm(void) continue;

if (strcmp(ASM_OPERANDS_TEMPLATE(body), - "call stackleak_track_stack")) { + "call __sanitizer_cov_stack_depth")) { continue; }

@@ -389,7 +389,7 @@ static bool remove_stack_tracking_gasm(void)

/* * Work with the RTL representation of the code. - * Remove the unneeded stackleak_track_stack() calls from the functions + * Remove the unneeded __sanitizer_cov_stack_depth() calls from the functions * which don't call alloca() and don't have a large enough stack frame size. */ static unsigned int stackleak_cleanup_execute(void) @@ -474,13 +474,13 @@ static bool stackleak_gate(void) return track_frame_size >= 0; }

-/* Build the function declaration for stackleak_track_stack() */ +/* Build the function declaration for __sanitizer_cov_stack_depth() */ static void stackleak_start_unit(void *gcc_data __unused, void *user_data __unused) { tree fntype;

- /* void stackleak_track_stack(void) */ + /* void __sanitizer_cov_stack_depth(void) */ fntype = build_function_type_list(void_type_node, NULL_TREE); track_function_decl = build_fn_decl(track_function, fntype); DECL_ASSEMBLER_NAME(track_function_decl); /* for LTO */ diff --git a/security/Kconfig.hardening b/security/Kconfig.hardening index 8aa5c1d4794d..edcc489a6805 100644 --- a/security/Kconfig.hardening +++ b/security/Kconfig.hardening @@ -205,8 +205,8 @@ config STACKLEAK_TRACK_MIN_SIZE help The STACKLEAK options instruments the kernel code for tracking the lowest border of the kernel stack (and for some other purposes). - It inserts the stackleak_track_stack() call for the functions with - a stack frame size greater than or equal to this parameter. + It inserts the __sanitizer_cov_stack_depth() call for the functions + with a stack frame size greater than or equal to this parameter. If unsure, leave the default value 100.

config STACKLEAK_METRICS diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 3a411064fa34..05d0095c1384 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -1191,7 +1191,7 @@ static const char *uaccess_safe_builtin[] = { "__ubsan_handle_shift_out_of_bounds", "__ubsan_handle_load_invalid_value", /* STACKLEAK */ - "stackleak_track_stack", + "__sanitizer_cov_stack_depth", /* TRACE_BRANCH_PROFILING */ "ftrace_likely_update", /* STACKPROTECTOR */

-- 2.34.1

Kees Cook

7:01 p.m.

New subject: [PATCH RFC 3/4] stackleak: Split STACKLEAK_CFLAGS from GCC_PLUGINS_CFLAGS

In preparation for Clang stack depth tracking for stackleak, split the stackleak-specific cflags out of GCC_PLUGINS_CFLAGS into STACKLEAK_CFLAGS.

Signed-off-by: Kees Cook kees@kernel.org --- Cc: Arnd Bergmann arnd@arndb.de Cc: x86@kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: sparclinux@vger.kernel.org Cc: linux-kbuild@vger.kernel.org Cc: linux-hardening@vger.kernel.org --- arch/arm/vdso/Makefile | 2 +- arch/arm64/kernel/vdso/Makefile | 1 + arch/sparc/vdso/Makefile | 3 ++- arch/x86/entry/vdso/Makefile | 3 ++- scripts/Makefile.gcc-plugins | 11 ++++++----- 5 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/arch/arm/vdso/Makefile b/arch/arm/vdso/Makefile index cb044bfd145d..92748e341b7d 100644 --- a/arch/arm/vdso/Makefile +++ b/arch/arm/vdso/Makefile @@ -26,7 +26,7 @@ CPPFLAGS_vdso.lds += -P -C -U$(ARCH) CFLAGS_REMOVE_vdso.o = -pg

# Force -O2 to avoid libgcc dependencies -CFLAGS_REMOVE_vgettimeofday.o = -pg -Os $(RANDSTRUCT_CFLAGS) $(GCC_PLUGINS_CFLAGS) +CFLAGS_REMOVE_vgettimeofday.o = -pg -Os $(RANDSTRUCT_CFLAGS) $(GCC_PLUGINS_CFLAGS) $(STACKLEAK_CFLAGS) ifeq ($(c-gettimeofday-y),) CFLAGS_vgettimeofday.o = -O2 else diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile index 5e27e46aa496..fb17749b93cf 100644 --- a/arch/arm64/kernel/vdso/Makefile +++ b/arch/arm64/kernel/vdso/Makefile @@ -37,6 +37,7 @@ ccflags-y += -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO # the CFLAGS to make possible to build the kernel with CONFIG_WERROR enabled. CC_FLAGS_REMOVE_VDSO := $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_SCS) \ $(RANDSTRUCT_CFLAGS) $(GCC_PLUGINS_CFLAGS) \ + $(STACKLEAK_CFLAGS) \ $(CC_FLAGS_LTO) $(CC_FLAGS_CFI) \ -Wmissing-prototypes -Wmissing-declarations

diff --git a/arch/sparc/vdso/Makefile b/arch/sparc/vdso/Makefile index fdc4a8f5a49c..162a0235f41f 100644 --- a/arch/sparc/vdso/Makefile +++ b/arch/sparc/vdso/Makefile @@ -48,7 +48,7 @@ CFL := $(PROFILING) -mcmodel=medlow -fPIC -O2 -fasynchronous-unwind-tables -m64

SPARC_REG_CFLAGS = -ffixed-g4 -ffixed-g5 $(call cc-option,-fcall-used-g5) $(call cc-option,-fcall-used-g7)

-$(vobjs): KBUILD_CFLAGS := $(filter-out $(RANDSTRUCT_CFLAGS) $(GCC_PLUGINS_CFLAGS) $(SPARC_REG_CFLAGS),$(KBUILD_CFLAGS)) $(CFL) +$(vobjs): KBUILD_CFLAGS := $(filter-out $(RANDSTRUCT_CFLAGS) $(GCC_PLUGINS_CFLAGS) $(STACKLEAK_CFLAGS) $(SPARC_REG_CFLAGS),$(KBUILD_CFLAGS)) $(CFL)

# # vDSO code runs in userspace and -pg doesn't help with profiling anyway. @@ -80,6 +80,7 @@ KBUILD_CFLAGS_32 := $(filter-out -mcmodel=medlow,$(KBUILD_CFLAGS_32)) KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32)) KBUILD_CFLAGS_32 := $(filter-out $(RANDSTRUCT_CFLAGS),$(KBUILD_CFLAGS_32)) KBUILD_CFLAGS_32 := $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS_32)) +KBUILD_CFLAGS_32 := $(filter-out $(STACKLEAK_CFLAGS),$(KBUILD_CFLAGS_32)) KBUILD_CFLAGS_32 := $(filter-out $(SPARC_REG_CFLAGS),$(KBUILD_CFLAGS_32)) KBUILD_CFLAGS_32 += -m32 -msoft-float -fpic KBUILD_CFLAGS_32 += -fno-stack-protector diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile index 54d3e9774d62..cd5249b6ef84 100644 --- a/arch/x86/entry/vdso/Makefile +++ b/arch/x86/entry/vdso/Makefile @@ -62,7 +62,7 @@ ifneq ($(RETPOLINE_VDSO_CFLAGS),) endif endif

-$(vobjs): KBUILD_CFLAGS := $(filter-out $(PADDING_CFLAGS) $(CC_FLAGS_LTO) $(CC_FLAGS_CFI) $(RANDSTRUCT_CFLAGS) $(GCC_PLUGINS_CFLAGS) $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS)) $(CFL) +$(vobjs): KBUILD_CFLAGS := $(filter-out $(PADDING_CFLAGS) $(CC_FLAGS_LTO) $(CC_FLAGS_CFI) $(RANDSTRUCT_CFLAGS) $(GCC_PLUGINS_CFLAGS) $(STACKLEAK_CFLAGS) $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS)) $(CFL) $(vobjs): KBUILD_AFLAGS += -DBUILD_VDSO

# @@ -124,6 +124,7 @@ KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32)) KBUILD_CFLAGS_32 := $(filter-out -mfentry,$(KBUILD_CFLAGS_32)) KBUILD_CFLAGS_32 := $(filter-out $(RANDSTRUCT_CFLAGS),$(KBUILD_CFLAGS_32)) KBUILD_CFLAGS_32 := $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS_32)) +KBUILD_CFLAGS_32 := $(filter-out $(STACKLEAK_CFLAGS),$(KBUILD_CFLAGS_32)) KBUILD_CFLAGS_32 := $(filter-out $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS_32)) KBUILD_CFLAGS_32 := $(filter-out $(CC_FLAGS_LTO),$(KBUILD_CFLAGS_32)) KBUILD_CFLAGS_32 := $(filter-out $(CC_FLAGS_CFI),$(KBUILD_CFLAGS_32)) diff --git a/scripts/Makefile.gcc-plugins b/scripts/Makefile.gcc-plugins index e3ed92e20d16..398b70e2d270 100644 --- a/scripts/Makefile.gcc-plugins +++ b/scripts/Makefile.gcc-plugins @@ -23,18 +23,19 @@ gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STRUCTLEAK) \ += -DSTRUCTLEAK_PLUGIN

gcc-plugin-$(CONFIG_GCC_PLUGIN_STACKLEAK) += stackleak_plugin.so -gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK) \ +gcc-plugin-stackleak-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK) \ += -DSTACKLEAK_PLUGIN -gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK) \ +gcc-plugin-stackleak-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK) \ += -fplugin-arg-stackleak_plugin-track-min-size=$(CONFIG_STACKLEAK_TRACK_MIN_SIZE) -gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK) \ +gcc-plugin-stackleak-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK) \ += -fplugin-arg-stackleak_plugin-arch=$(SRCARCH) -gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK_VERBOSE) \ +gcc-plugin-stackleak-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK_VERBOSE) \ += -fplugin-arg-stackleak_plugin-verbose ifdef CONFIG_GCC_PLUGIN_STACKLEAK + STACKLEAK_CFLAGS = $(gcc-plugin-stackleak-cflags-y) DISABLE_STACKLEAK += -fplugin-arg-stackleak_plugin-disable endif -export DISABLE_STACKLEAK +export STACKLEAK_CFLAGS DISABLE_STACKLEAK

gcc-plugin-$(CONFIG_GCC_PLUGIN_ARM_SSP_PER_TASK) += arm_ssp_per_task_plugin.so ifdef CONFIG_GCC_PLUGIN_ARM_SSP_PER_TASK

-- 2.34.1

Kees Cook

7:01 p.m.

New subject: [PATCH RFC 4/4] stackleak: Support Clang stack depth tracking

Wire up stackleak to Clang's proposed[1] stack depth tracking callback option. While __noinstr already contained __no_sanitize_coverage, it was still needed for __init and __head section markings. This is needed to make sure the callback is not executed in unsupported contexts.

Link: https://github.com/llvm/llvm-project/pull/138323 [1] Signed-off-by: Kees Cook kees@kernel.org --- Cc: Arnd Bergmann arnd@arndb.de Cc: Thomas Gleixner tglx@linutronix.de Cc: Ingo Molnar mingo@redhat.com Cc: Borislav Petkov bp@alien8.de Cc: Dave Hansen dave.hansen@linux.intel.com Cc: x86@kernel.org Cc: "H. Peter Anvin" hpa@zytor.com Cc: Masahiro Yamada masahiroy@kernel.org Cc: Nathan Chancellor nathan@kernel.org Cc: Nicolas Schier nicolas.schier@linux.dev Cc: Marco Elver elver@google.com Cc: Andrey Konovalov andreyknvl@gmail.com Cc: Andrey Ryabinin ryabinin.a.a@gmail.com Cc: Ard Biesheuvel ardb@kernel.org Cc: "Gustavo A. R. Silva" gustavoars@kernel.org Cc: Paul Moore paul@paul-moore.com Cc: James Morris jmorris@namei.org Cc: "Serge E. Hallyn" serge@hallyn.com Cc: Kai Huang kai.huang@intel.com Cc: Hou Wenlong houwenlong.hwl@antgroup.com Cc: "Kirill A. Shutemov" kirill.shutemov@linux.intel.com Cc: Andrew Morton akpm@linux-foundation.org Cc: "Peter Zijlstra (Intel)" peterz@infradead.org Cc: Sami Tolvanen samitolvanen@google.com Cc: Christophe Leroy christophe.leroy@csgroup.eu Cc: linux-kbuild@vger.kernel.org Cc: kasan-dev@googlegroups.com Cc: linux-hardening@vger.kernel.org Cc: linux-security-module@vger.kernel.org --- arch/x86/include/asm/init.h | 2 +- include/linux/init.h | 4 +++- scripts/Makefile.ubsan | 12 ++++++++++++ security/Kconfig.hardening | 5 ++++- 4 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/init.h b/arch/x86/include/asm/init.h index 8b1b1abcef15..6bfdaeddbae8 100644 --- a/arch/x86/include/asm/init.h +++ b/arch/x86/include/asm/init.h @@ -5,7 +5,7 @@ #if defined(CONFIG_CC_IS_CLANG) && CONFIG_CLANG_VERSION < 170000 #define __head __section(".head.text") __no_sanitize_undefined __no_stack_protector #else -#define __head __section(".head.text") __no_sanitize_undefined +#define __head __section(".head.text") __no_sanitize_undefined __no_sanitize_coverage #endif

struct x86_mapping_info { diff --git a/include/linux/init.h b/include/linux/init.h index ee1309473bc6..c65a050d52a7 100644 --- a/include/linux/init.h +++ b/include/linux/init.h @@ -49,7 +49,9 @@

/* These are for everybody (although not all archs will actually discard it in modules) */ -#define __init __section(".init.text") __cold __latent_entropy __noinitretpoline +#define __init __section(".init.text") __cold __latent_entropy \ + __noinitretpoline \ + __no_sanitize_coverage #define __initdata __section(".init.data") #define __initconst __section(".init.rodata") #define __exitdata __section(".exit.data") diff --git a/scripts/Makefile.ubsan b/scripts/Makefile.ubsan index 9e35198edbf0..cfb3ecde07dd 100644 --- a/scripts/Makefile.ubsan +++ b/scripts/Makefile.ubsan @@ -22,3 +22,15 @@ ubsan-integer-wrap-cflags-$(CONFIG_UBSAN_INTEGER_WRAP) += \ -fsanitize=implicit-unsigned-integer-truncation \ -fsanitize-ignorelist=$(srctree)/scripts/integer-wrap-ignore.scl export CFLAGS_UBSAN_INTEGER_WRAP := $(ubsan-integer-wrap-cflags-y) + +ifdef CONFIG_CC_IS_CLANG +stackleak-cflags-$(CONFIG_STACKLEAK) += \ + -fsanitize-coverage=stack-depth \ + -fsanitize-coverage-stack-depth-callback-min=$(CONFIG_STACKLEAK_TRACK_MIN_SIZE) +export STACKLEAK_CFLAGS := $(stackleak-cflags-y) +ifdef CONFIG_STACKLEAK + DISABLE_STACKLEAK := -fno-sanitize-coverage=stack-depth +endif +export DISABLE_STACKLEAK +KBUILD_CFLAGS += $(STACKLEAK_CFLAGS) +endif diff --git a/security/Kconfig.hardening b/security/Kconfig.hardening index edcc489a6805..e86b61e44b33 100644 --- a/security/Kconfig.hardening +++ b/security/Kconfig.hardening @@ -158,10 +158,13 @@ config GCC_PLUGIN_STRUCTLEAK_VERBOSE initialized. Since not all existing initializers are detected by the plugin, this can produce false positive warnings.

+config CC_HAS_SANCOV_STACK_DEPTH_CALLBACK + def_bool $(cc-option,-fsanitize-coverage-stack-depth-callback-min=1) + config STACKLEAK bool "Poison kernel stack before returning from syscalls" depends on HAVE_ARCH_STACKLEAK - depends on GCC_PLUGINS + depends on GCC_PLUGINS || CC_HAS_SANCOV_STACK_DEPTH_CALLBACK help This option makes the kernel erase the kernel stack before returning from system calls. This has the effect of leaving

-- 2.34.1

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Kees Cook