stackleak: Rename STACKLEAK to KSTACK_ERASE

In preparation for adding Clang sanitizer coverage stack depth tracking
that can support stack depth callbacks:

- Add the new top-level CONFIG_KSTACK_ERASE option which will be
  implemented either with the stackleak GCC plugin, or with the Clang
  stack depth callback support.
- Rename CONFIG_GCC_PLUGIN_STACKLEAK as needed to CONFIG_KSTACK_ERASE,
  but keep it for anything specific to the GCC plugin itself.
- Rename all exposed "STACKLEAK" names and files to "KSTACK_ERASE" (named
  for what it does rather than what it protects against), but leave as
  many of the internals alone as possible to avoid even more churn.

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

Suggested-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20250717232519.2984886-1-kees@kernel.org
Signed-off-by: Kees Cook <kees@kernel.org>

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_KSTACK_ERASE``.
 
 That erasing reduces the information which kernel stack leak bugs
 can reveal and blocks some uninitialized stack variable attacks.
@@ -1473,7 +1473,7 @@ The tradeoff is the performance impact: on a single CPU system kernel
 compilation sees a 1% slowdown, other systems and workloads may vary.
 
 = ====================================================================
-0 Kernel stack erasing is disabled, STACKLEAK_METRICS are not updated.
+0 Kernel stack erasing is disabled, KSTACK_ERASE_METRICS are not updated.
 1 Kernel stack erasing is enabled (default), it is performed before
   returning to the userspace at the end of syscalls.
 = ====================================================================

Documentation/arch/x86/x86_64/mm.rst

@@ -176,5 +176,5 @@ Be very careful vs. KASLR when changing anything here. The KASLR address
 range must not overlap with anything except the KASAN shadow area, which is
 correct as KASAN disables KASLR.
 
-For both 4- and 5-level layouts, the STACKLEAK_POISON value in the last 2MB
+For both 4- and 5-level layouts, the KSTACK_ERASE_POISON value in the last 2MB
 hole: ffffffffffff4111

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_KSTACK_ERASE``), wipe heap memory on a
 free. This frustrates many uninitialized variable attacks, stack content
 exposures, heap content exposures, and use-after-free attacks.
 

Documentation/translations/zh_CN/security/self-protection.rst

@@ -259,7 +259,7 @@ KALLSYSM，则会直接打印原始地址。
 --------
 
 在释放内存时，最好对内存内容进行清除处理，以防止攻击者重用内存中以前
-的内容。例如，在系统调用返回时清除堆栈（CONFIG_GCC_PLUGIN_STACKLEAK）,
+的内容。例如，在系统调用返回时清除堆栈（CONFIG_KSTACK_ERASE）,
 在释放堆内容是清除其内容。这有助于防止许多未初始化变量攻击、堆栈内容
 泄露、堆内容泄露以及使用后释放攻击（user-after-free）。
 

MAINTAINERS

@@ -9992,8 +9992,6 @@ L:	linux-hardening@vger.kernel.org
 S:	Maintained
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git for-next/hardening
 F:	Documentation/kbuild/gcc-plugins.rst
-F:	include/linux/stackleak.h
-F:	kernel/stackleak.c
 F:	scripts/Makefile.gcc-plugins
 F:	scripts/gcc-plugins/
 
@@ -13087,10 +13085,12 @@ T:	git git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git for-next/har
 F:	Documentation/ABI/testing/sysfs-kernel-oops_count
 F:	Documentation/ABI/testing/sysfs-kernel-warn_count
 F:	arch/*/configs/hardening.config
+F:	include/linux/kstack_erase.h
 F:	include/linux/overflow.h
 F:	include/linux/randomize_kstack.h
 F:	include/linux/ucopysize.h
 F:	kernel/configs/hardening.config
+F:	kernel/kstack_erase.c
 F:	lib/tests/randstruct_kunit.c
 F:	lib/tests/usercopy_kunit.c
 F:	mm/usercopy.c

arch/Kconfig

@@ -630,11 +630,11 @@ config SECCOMP_CACHE_DEBUG
 
 	  If unsure, say N.
 
-config HAVE_ARCH_STACKLEAK
+config HAVE_ARCH_KSTACK_ERASE
 	bool
 	help
 	  An architecture should select this if it has the code which
-	  fills the used part of the kernel stack with the STACKLEAK_POISON
+	  fills the used part of the kernel stack with the KSTACK_ERASE_POISON
 	  value before returning from system calls.
 
 config HAVE_STACKPROTECTOR

arch/arm/Kconfig

@@ -87,11 +87,11 @@ config ARM
 	select HAVE_ARCH_KGDB if !CPU_ENDIAN_BE32 && MMU
 	select HAVE_ARCH_KASAN if MMU && !XIP_KERNEL
 	select HAVE_ARCH_KASAN_VMALLOC if HAVE_ARCH_KASAN
+	select HAVE_ARCH_KSTACK_ERASE
 	select HAVE_ARCH_MMAP_RND_BITS if MMU
 	select HAVE_ARCH_PFN_VALID
 	select HAVE_ARCH_SECCOMP
 	select HAVE_ARCH_SECCOMP_FILTER if AEABI && !OABI_COMPAT
-	select HAVE_ARCH_STACKLEAK
 	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
 	select HAVE_ARCH_TRACEHOOK
 	select HAVE_ARCH_TRANSPARENT_HUGEPAGE if ARM_LPAE

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 += $(DISABLE_KSTACK_ERASE)
 ifeq ($(CONFIG_DEBUG_UNCOMPRESS),y)
 OBJS	+= debug.o
 AFLAGS_head.o += -DDEBUG

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_KSTACK_ERASE
 	bl	stackleak_erase_on_task_stack
 #endif
 	restore_user_regs fast = 0, offset = 0

arch/arm64/Kconfig

@@ -187,12 +187,12 @@ config ARM64
 	select HAVE_ARCH_KCSAN if EXPERT
 	select HAVE_ARCH_KFENCE
 	select HAVE_ARCH_KGDB
+	select HAVE_ARCH_KSTACK_ERASE
 	select HAVE_ARCH_MMAP_RND_BITS
 	select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
 	select HAVE_ARCH_PREL32_RELOCATIONS
 	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
 	select HAVE_ARCH_SECCOMP_FILTER
-	select HAVE_ARCH_STACKLEAK
 	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
 	select HAVE_ARCH_TRACEHOOK
 	select HAVE_ARCH_TRANSPARENT_HUGEPAGE

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_KSTACK_ERASE
 	bl	stackleak_erase_on_task_stack
 #endif
 	kernel_exit 0

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_KSTACK_ERASE) \
 		   $(DISABLE_LATENT_ENTROPY_PLUGIN) \
 		   $(call cc-option,-mbranch-protection=none) \
 		   -I$(srctree)/scripts/dtc/libfdt -fno-stack-protector \

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_KSTACK_ERASE)
 
 hostprogs := gen-hyprel
 HOST_EXTRACFLAGS += -I$(objtree)/include

arch/loongarch/Kconfig

@@ -120,11 +120,11 @@ config LOONGARCH
 	select HAVE_ARCH_KASAN
 	select HAVE_ARCH_KFENCE
 	select HAVE_ARCH_KGDB if PERF_EVENTS
+	select HAVE_ARCH_KSTACK_ERASE
 	select HAVE_ARCH_MMAP_RND_BITS if MMU
 	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
 	select HAVE_ARCH_SECCOMP
 	select HAVE_ARCH_SECCOMP_FILTER
-	select HAVE_ARCH_STACKLEAK
 	select HAVE_ARCH_TRACEHOOK
 	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
 	select HAVE_ARCH_USERFAULTFD_MINOR if USERFAULTFD

arch/riscv/Kconfig

@@ -135,13 +135,13 @@ config RISCV
 	select HAVE_ARCH_KASAN if MMU && 64BIT
 	select HAVE_ARCH_KASAN_VMALLOC if MMU && 64BIT
 	select HAVE_ARCH_KFENCE if MMU && 64BIT
+	select HAVE_ARCH_KSTACK_ERASE
 	select HAVE_ARCH_KGDB if !XIP_KERNEL
 	select HAVE_ARCH_KGDB_QXFER_PKT
 	select HAVE_ARCH_MMAP_RND_BITS if MMU
 	select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
 	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
 	select HAVE_ARCH_SECCOMP_FILTER
-	select HAVE_ARCH_STACKLEAK
 	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
 	select HAVE_ARCH_TRACEHOOK
 	select HAVE_ARCH_TRANSPARENT_HUGEPAGE if 64BIT && MMU

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_KSTACK_ERASE
 	call	stackleak_erase_on_task_stack
 #endif
 

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_KSTACK_ERASE) \
 		   $(call cc-option,-mbranch-protection=none) \
 		   -I$(srctree)/scripts/dtc/libfdt -fno-stack-protector \
 		   -include $(srctree)/include/linux/hidden.h \

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_KSTACK_ERASE) -DDISABLE_BRANCH_PROFILING
 PURGATORY_CFLAGS += -fno-stack-protector -g0
 
 # Default KBUILD_CFLAGS can have -pg option set when FTRACE is enabled. That

arch/s390/Kconfig

@@ -176,10 +176,10 @@ config S390
 	select HAVE_ARCH_KCSAN
 	select HAVE_ARCH_KMSAN
 	select HAVE_ARCH_KFENCE
+	select HAVE_ARCH_KSTACK_ERASE
 	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
 	select HAVE_ARCH_SECCOMP_FILTER
 	select HAVE_ARCH_SOFT_DIRTY
-	select HAVE_ARCH_STACKLEAK
 	select HAVE_ARCH_TRACEHOOK
 	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
 	select HAVE_ARCH_VMAP_STACK

arch/s390/kernel/entry.S

@@ -124,7 +124,7 @@ _LPP_OFFSET	= __LC_LPP
 #endif
 
 	.macro STACKLEAK_ERASE
-#ifdef CONFIG_GCC_PLUGIN_STACKLEAK
+#ifdef CONFIG_KSTACK_ERASE
 	brasl	%r14,stackleak_erase_on_task_stack
 #endif
 	.endm

arch/x86/Kconfig

@@ -204,13 +204,13 @@ config X86
 	select HAVE_ARCH_KFENCE
 	select HAVE_ARCH_KMSAN			if X86_64
 	select HAVE_ARCH_KGDB
+	select HAVE_ARCH_KSTACK_ERASE
 	select HAVE_ARCH_MMAP_RND_BITS		if MMU
 	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
 	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
 	select HAVE_ARCH_PREL32_RELOCATIONS
 	select HAVE_ARCH_SECCOMP_FILTER
 	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
-	select HAVE_ARCH_STACKLEAK
 	select HAVE_ARCH_TRACEHOOK
 	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
 	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64

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_KSTACK_ERASE
 	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_KSTACK_ERASE
 	call stackleak_erase
 #endif
 .endm

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_KSTACK_ERASE) -DDISABLE_BRANCH_PROFILING
 PURGATORY_CFLAGS += -fno-stack-protector
 
 # Default KBUILD_CFLAGS can have -pg option set when FTRACE is enabled. That

drivers/firmware/efi/libstub/Makefile

@@ -22,16 +22,16 @@ 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 $(DISABLE_KSTACK_ERASE) \
 				   -fno-unwind-tables -fno-asynchronous-unwind-tables
 cflags-$(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)
+				   $(DISABLE_KSTACK_ERASE)
 cflags-$(CONFIG_RISCV)		+= -fpic -DNO_ALTERNATIVE -mno-relax \
-				   $(DISABLE_STACKLEAK_PLUGIN)
+				   $(DISABLE_KSTACK_ERASE)
-cflags-$(CONFIG_LOONGARCH)	+= -fpie $(DISABLE_STACKLEAK_PLUGIN)
+cflags-$(CONFIG_LOONGARCH)	+= -fpie $(DISABLE_KSTACK_ERASE)
 
 cflags-$(CONFIG_EFI_PARAMS_FROM_FDT)	+= -I$(srctree)/scripts/dtc/libfdt
 

drivers/misc/lkdtm/Makefile

@@ -8,7 +8,7 @@ lkdtm-$(CONFIG_LKDTM)		+= perms.o
 lkdtm-$(CONFIG_LKDTM)		+= refcount.o
 lkdtm-$(CONFIG_LKDTM)		+= rodata_objcopy.o
 lkdtm-$(CONFIG_LKDTM)		+= usercopy.o
-lkdtm-$(CONFIG_LKDTM)		+= stackleak.o
+lkdtm-$(CONFIG_LKDTM)		+= kstack_erase.o
 lkdtm-$(CONFIG_LKDTM)		+= cfi.o
 lkdtm-$(CONFIG_LKDTM)		+= fortify.o
 lkdtm-$(CONFIG_PPC_64S_HASH_MMU)	+= powerpc.o

drivers/misc/lkdtm/kstack_erase.c

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
  * This code tests that the current task stack is properly erased (filled
- * with STACKLEAK_POISON).
+ * with KSTACK_ERASE_POISON).
  *
  * Authors:
  *   Alexander Popov <alex.popov@linux.com>
@@ -9,9 +9,9 @@
  */
 
 #include "lkdtm.h"
-#include <linux/stackleak.h>
+#include <linux/kstack_erase.h>
 
-#if defined(CONFIG_GCC_PLUGIN_STACKLEAK)
+#if defined(CONFIG_KSTACK_ERASE)
 /*
  * Check that stackleak tracks the lowest stack pointer and erases the stack
  * below this as expected.
@@ -85,7 +85,7 @@ static void noinstr check_stackleak_irqoff(void)
 	while (poison_low > task_stack_low) {
 		poison_low -= sizeof(unsigned long);
 
-		if (*(unsigned long *)poison_low == STACKLEAK_POISON)
+		if (*(unsigned long *)poison_low == KSTACK_ERASE_POISON)
 			continue;
 
 		instrumentation_begin();
@@ -96,7 +96,7 @@ static void noinstr check_stackleak_irqoff(void)
 	}
 
 	instrumentation_begin();
-	pr_info("stackleak stack usage:\n"
+	pr_info("kstack erase stack usage:\n"
 		"  high offset: %lu bytes\n"
 		"  current:     %lu bytes\n"
 		"  lowest:      %lu bytes\n"
@@ -121,7 +121,7 @@ static void noinstr check_stackleak_irqoff(void)
 	instrumentation_end();
 }
 
-static void lkdtm_STACKLEAK_ERASING(void)
+static void lkdtm_KSTACK_ERASE(void)
 {
 	unsigned long flags;
 
@@ -129,19 +129,19 @@ static void lkdtm_STACKLEAK_ERASING(void)
 	check_stackleak_irqoff();
 	local_irq_restore(flags);
 }
-#else /* defined(CONFIG_GCC_PLUGIN_STACKLEAK) */
+#else /* defined(CONFIG_KSTACK_ERASE) */
-static void lkdtm_STACKLEAK_ERASING(void)
+static void lkdtm_KSTACK_ERASE(void)
 {
-	if (IS_ENABLED(CONFIG_HAVE_ARCH_STACKLEAK)) {
+	if (IS_ENABLED(CONFIG_HAVE_ARCH_KSTACK_ERASE)) {
-		pr_err("XFAIL: stackleak is not enabled (CONFIG_GCC_PLUGIN_STACKLEAK=n)\n");
+		pr_err("XFAIL: stackleak is not enabled (CONFIG_KSTACK_ERASE=n)\n");
 	} else {
-		pr_err("XFAIL: stackleak is not supported on this arch (HAVE_ARCH_STACKLEAK=n)\n");
+		pr_err("XFAIL: stackleak is not supported on this arch (HAVE_ARCH_KSTACK_ERASE=n)\n");
 	}
 }
-#endif /* defined(CONFIG_GCC_PLUGIN_STACKLEAK) */
+#endif /* defined(CONFIG_KSTACK_ERASE) */
 
 static struct crashtype crashtypes[] = {
-	CRASHTYPE(STACKLEAK_ERASING),
+	CRASHTYPE(KSTACK_ERASE),
 };
 
 struct crashtype_category stackleak_crashtypes = {

fs/proc/base.c

@@ -3291,7 +3291,7 @@ static int proc_pid_ksm_stat(struct seq_file *m, struct pid_namespace *ns,
 }
 #endif /* CONFIG_KSM */
 
-#ifdef CONFIG_STACKLEAK_METRICS
+#ifdef CONFIG_KSTACK_ERASE_METRICS
 static int proc_stack_depth(struct seq_file *m, struct pid_namespace *ns,
 				struct pid *pid, struct task_struct *task)
 {
@@ -3304,7 +3304,7 @@ static int proc_stack_depth(struct seq_file *m, struct pid_namespace *ns,
 							prev_depth, depth);
 	return 0;
 }
-#endif /* CONFIG_STACKLEAK_METRICS */
+#endif /* CONFIG_KSTACK_ERASE_METRICS */
 
 /*
  * Thread groups
@@ -3411,7 +3411,7 @@ static const struct pid_entry tgid_base_stuff[] = {
 #ifdef CONFIG_LIVEPATCH
 	ONE("patch_state",  S_IRUSR, proc_pid_patch_state),
 #endif
-#ifdef CONFIG_STACKLEAK_METRICS
+#ifdef CONFIG_KSTACK_ERASE_METRICS
 	ONE("stack_depth", S_IRUGO, proc_stack_depth),
 #endif
 #ifdef CONFIG_PROC_PID_ARCH_STATUS

include/linux/kstack_erase.h

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _LINUX_STACKLEAK_H
+#ifndef _LINUX_KSTACK_ERASE_H
-#define _LINUX_STACKLEAK_H
+#define _LINUX_KSTACK_ERASE_H
 
 #include <linux/sched.h>
 #include <linux/sched/task_stack.h>
@@ -9,10 +9,10 @@
  * Check that the poison value points to the unused hole in the
  * virtual memory map for your platform.
  */
-#define STACKLEAK_POISON -0xBEEF
+#define KSTACK_ERASE_POISON -0xBEEF
-#define STACKLEAK_SEARCH_DEPTH 128
+#define KSTACK_ERASE_SEARCH_DEPTH 128
 
-#ifdef CONFIG_GCC_PLUGIN_STACKLEAK
+#ifdef CONFIG_KSTACK_ERASE
 #include <asm/stacktrace.h>
 #include <linux/linkage.h>
 
@@ -50,7 +50,7 @@ stackleak_task_high_bound(const struct task_struct *tsk)
 static __always_inline unsigned long
 stackleak_find_top_of_poison(const unsigned long low, const unsigned long high)
 {
-	const unsigned int depth = STACKLEAK_SEARCH_DEPTH / sizeof(unsigned long);
+	const unsigned int depth = KSTACK_ERASE_SEARCH_DEPTH / sizeof(unsigned long);
 	unsigned int poison_count = 0;
 	unsigned long poison_high = high;
 	unsigned long sp = high;
@@ -58,7 +58,7 @@ stackleak_find_top_of_poison(const unsigned long low, const unsigned long high)
 	while (sp > low && poison_count < depth) {
 		sp -= sizeof(unsigned long);
 
-		if (*(unsigned long *)sp == STACKLEAK_POISON) {
+		if (*(unsigned long *)sp == KSTACK_ERASE_POISON) {
 			poison_count++;
 		} else {
 			poison_count = 0;
@@ -72,7 +72,7 @@ stackleak_find_top_of_poison(const unsigned long low, const unsigned long high)
 static inline void stackleak_task_init(struct task_struct *t)
 {
 	t->lowest_stack = stackleak_task_low_bound(t);
-# ifdef CONFIG_STACKLEAK_METRICS
+# ifdef CONFIG_KSTACK_ERASE_METRICS
 	t->prev_lowest_stack = t->lowest_stack;
 # endif
 }
@@ -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_KSTACK_ERASE */
 static inline void stackleak_task_init(struct task_struct *t) { }
 #endif
 

include/linux/sched.h

@@ -1607,8 +1607,10 @@ 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_KSTACK_ERASE
 	unsigned long			lowest_stack;
+#endif
+#ifdef CONFIG_KSTACK_ERASE_METRICS
 	unsigned long			prev_lowest_stack;
 #endif
 

kernel/Makefile

@@ -139,11 +139,11 @@ 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)
+CFLAGS_kstack_erase.o += $(DISABLE_KSTACK_ERASE)
-obj-$(CONFIG_GCC_PLUGIN_STACKLEAK) += stackleak.o
+obj-$(CONFIG_KSTACK_ERASE) += kstack_erase.o
-KASAN_SANITIZE_stackleak.o := n
+KASAN_SANITIZE_kstack_erase.o := n
-KCSAN_SANITIZE_stackleak.o := n
+KCSAN_SANITIZE_kstack_erase.o := n
-KCOV_INSTRUMENT_stackleak.o := n
+KCOV_INSTRUMENT_kstack_erase.o := n
 
 obj-$(CONFIG_SCF_TORTURE_TEST) += scftorture.o
 

kernel/fork.c

@@ -93,7 +93,7 @@
 #include <linux/kcov.h>
 #include <linux/livepatch.h>
 #include <linux/thread_info.h>
-#include <linux/stackleak.h>
+#include <linux/kstack_erase.h>
 #include <linux/kasan.h>
 #include <linux/scs.h>
 #include <linux/io_uring.h>

kernel/kstack_erase.c

@@ -6,14 +6,14 @@
  *
  * Author: Alexander Popov <alex.popov@linux.com>
  *
- * STACKLEAK reduces the information which kernel stack leak bugs can
+ * KSTACK_ERASE reduces the information which kernel stack leak bugs can
  * reveal and blocks some uninitialized stack variable attacks.
  */
 
-#include <linux/stackleak.h>
+#include <linux/kstack_erase.h>
 #include <linux/kprobes.h>
 
-#ifdef CONFIG_STACKLEAK_RUNTIME_DISABLE
+#ifdef CONFIG_KSTACK_ERASE_RUNTIME_DISABLE
 #include <linux/jump_label.h>
 #include <linux/string_choices.h>
 #include <linux/sysctl.h>
@@ -68,7 +68,7 @@ late_initcall(stackleak_sysctls_init);
 #define skip_erasing()	static_branch_unlikely(&stack_erasing_bypass)
 #else
 #define skip_erasing()	false
-#endif /* CONFIG_STACKLEAK_RUNTIME_DISABLE */
+#endif /* CONFIG_KSTACK_ERASE_RUNTIME_DISABLE */
 
 #ifndef __stackleak_poison
 static __always_inline void __stackleak_poison(unsigned long erase_low,
@@ -91,7 +91,7 @@ static __always_inline void __stackleak_erase(bool on_task_stack)
 	erase_low = stackleak_find_top_of_poison(task_stack_low,
 						 current->lowest_stack);
 
-#ifdef CONFIG_STACKLEAK_METRICS
+#ifdef CONFIG_KSTACK_ERASE_METRICS
 	current->prev_lowest_stack = erase_low;
 #endif
 
@@ -113,7 +113,7 @@ static __always_inline void __stackleak_erase(bool on_task_stack)
 	else
 		erase_high = task_stack_high;
 
-	__stackleak_poison(erase_low, erase_high, STACKLEAK_POISON);
+	__stackleak_poison(erase_low, erase_high, KSTACK_ERASE_POISON);
 
 	/* Reset the 'lowest_stack' value for the next syscall */
 	current->lowest_stack = task_stack_high;
@@ -161,11 +161,11 @@ void __used __no_caller_saved_registers noinstr stackleak_track_stack(void)
 	unsigned long sp = current_stack_pointer;
 
 	/*
-	 * Having CONFIG_STACKLEAK_TRACK_MIN_SIZE larger than
+	 * Having CONFIG_KSTACK_ERASE_TRACK_MIN_SIZE larger than
-	 * STACKLEAK_SEARCH_DEPTH makes the poison search in
+	 * KSTACK_ERASE_SEARCH_DEPTH makes the poison search in
 	 * stackleak_erase() unreliable. Let's prevent that.
 	 */
-	BUILD_BUG_ON(CONFIG_STACKLEAK_TRACK_MIN_SIZE > STACKLEAK_SEARCH_DEPTH);
+	BUILD_BUG_ON(CONFIG_KSTACK_ERASE_TRACK_MIN_SIZE > KSTACK_ERASE_SEARCH_DEPTH);
 
 	/* 'lowest_stack' should be aligned on the register width boundary */
 	sp = ALIGN(sp, sizeof(unsigned long));

lib/Makefile

@@ -337,7 +337,7 @@ 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_KSTACK_ERASE)
 
 obj-$(CONFIG_SBITMAP) += sbitmap.o
 

scripts/Makefile.gcc-plugins

@@ -12,15 +12,15 @@ gcc-plugin-$(CONFIG_GCC_PLUGIN_STACKLEAK)	+= stackleak_plugin.so
 gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK)		\
 		+= -DSTACKLEAK_PLUGIN
 gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK)		\
-		+= -fplugin-arg-stackleak_plugin-track-min-size=$(CONFIG_STACKLEAK_TRACK_MIN_SIZE)
+		+= -fplugin-arg-stackleak_plugin-track-min-size=$(CONFIG_KSTACK_ERASE_TRACK_MIN_SIZE)
 gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK)		\
 		+= -fplugin-arg-stackleak_plugin-arch=$(SRCARCH)
 gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK_VERBOSE)	\
 		+= -fplugin-arg-stackleak_plugin-verbose
 ifdef CONFIG_GCC_PLUGIN_STACKLEAK
-    DISABLE_STACKLEAK_PLUGIN += -fplugin-arg-stackleak_plugin-disable
+    DISABLE_KSTACK_ERASE += -fplugin-arg-stackleak_plugin-disable
 endif
-export DISABLE_STACKLEAK_PLUGIN
+export DISABLE_KSTACK_ERASE
 
 # All the plugin CFLAGS are collected here in case a build target needs to
 # filter them out of the KBUILD_CFLAGS.

security/Kconfig.hardening

@@ -82,10 +82,10 @@ choice
 
 endchoice
 
-config GCC_PLUGIN_STACKLEAK
+config KSTACK_ERASE
 	bool "Poison kernel stack before returning from syscalls"
+	depends on HAVE_ARCH_KSTACK_ERASE
 	depends on GCC_PLUGINS
-	depends on HAVE_ARCH_STACKLEAK
 	help
 	  This option makes the kernel erase the kernel stack before
 	  returning from system calls. This has the effect of leaving
@@ -103,6 +103,10 @@ config GCC_PLUGIN_STACKLEAK
 	  are advised to test this feature on your expected workload before
 	  deploying it.
 
+config GCC_PLUGIN_STACKLEAK
+	def_bool KSTACK_ERASE
+	depends on GCC_PLUGINS
+	help
 	  This plugin was ported from grsecurity/PaX. More information at:
 	   * https://grsecurity.net/
 	   * https://pax.grsecurity.net/
@@ -117,37 +121,37 @@ config GCC_PLUGIN_STACKLEAK_VERBOSE
 	  instrumented. This is useful for comparing coverage between
 	  builds.
 
-config STACKLEAK_TRACK_MIN_SIZE
+config KSTACK_ERASE_TRACK_MIN_SIZE
-	int "Minimum stack frame size of functions tracked by STACKLEAK"
+	int "Minimum stack frame size of functions tracked by KSTACK_ERASE"
 	default 100
 	range 0 4096
-	depends on GCC_PLUGIN_STACKLEAK
+	depends on KSTACK_ERASE
 	help
-	  The STACKLEAK gcc plugin instruments the kernel code for tracking
+	  The KSTACK_ERASE option 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.
 	  If unsure, leave the default value 100.
 
-config STACKLEAK_METRICS
+config KSTACK_ERASE_METRICS
-	bool "Show STACKLEAK metrics in the /proc file system"
+	bool "Show KSTACK_ERASE metrics in the /proc file system"
-	depends on GCC_PLUGIN_STACKLEAK
+	depends on KSTACK_ERASE
 	depends on PROC_FS
 	help
-	  If this is set, STACKLEAK metrics for every task are available in
+	  If this is set, KSTACK_ERASE metrics for every task are available
-	  the /proc file system. In particular, /proc/<pid>/stack_depth
+	  in the /proc file system. In particular, /proc/<pid>/stack_depth
 	  shows the maximum kernel stack consumption for the current and
 	  previous syscalls. Although this information is not precise, it
-	  can be useful for estimating the STACKLEAK performance impact for
+	  can be useful for estimating the KSTACK_ERASE performance impact
-	  your workloads.
+	  for your workloads.
 
-config STACKLEAK_RUNTIME_DISABLE
+config KSTACK_ERASE_RUNTIME_DISABLE
 	bool "Allow runtime disabling of kernel stack erasing"
-	depends on GCC_PLUGIN_STACKLEAK
+	depends on KSTACK_ERASE
 	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_KSTACK_ERASE.
 
 config INIT_ON_ALLOC_DEFAULT_ON
 	bool "Enable heap memory zeroing on allocation by default"

tools/objtool/check.c

@@ -1192,7 +1192,7 @@ static const char *uaccess_safe_builtin[] = {
 	"__ubsan_handle_type_mismatch_v1",
 	"__ubsan_handle_shift_out_of_bounds",
 	"__ubsan_handle_load_invalid_value",
-	/* STACKLEAK */
+	/* KSTACK_ERASE */
 	"stackleak_track_stack",
 	/* TRACE_BRANCH_PROFILING */
 	"ftrace_likely_update",

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_KSTACK_ERASE=y
 CONFIG_HARDENED_USERCOPY=y
 CONFIG_RANDOMIZE_KSTACK_OFFSET_DEFAULT=y
 CONFIG_INIT_ON_FREE_DEFAULT_ON=y