Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

11 files changed, 2438 insertions, 0 deletions

diff --git a/drivers/misc/lkdtm/Makefile b/drivers/misc/lkdtm/Makefile
new file mode 100644
index 000000000..4405fb2bc
--- /dev/null
+++ b/drivers/misc/lkdtm/Makefile
@@ -0,0 +1,22 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_LKDTM)		+= lkdtm.o
+
+lkdtm-$(CONFIG_LKDTM)		+= core.o
+lkdtm-$(CONFIG_LKDTM)		+= bugs.o
+lkdtm-$(CONFIG_LKDTM)		+= heap.o
+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)		+= cfi.o
+
+KASAN_SANITIZE_stackleak.o	:= n
+KCOV_INSTRUMENT_rodata.o	:= n
+
+OBJCOPYFLAGS :=
+OBJCOPYFLAGS_rodata_objcopy.o	:= \
+			--rename-section .noinstr.text=.rodata,alloc,readonly,load,contents
+targets += rodata.o rodata_objcopy.o
+$(obj)/rodata_objcopy.o: $(obj)/rodata.o FORCE
+	$(call if_changed,objcopy)
diff --git a/drivers/misc/lkdtm/bugs.c b/drivers/misc/lkdtm/bugs.c
new file mode 100644
index 000000000..d39b8139b
--- /dev/null
+++ b/drivers/misc/lkdtm/bugs.c
@@ -0,0 +1,492 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This is for all the tests related to logic bugs (e.g. bad dereferences,
+ * bad alignment, bad loops, bad locking, bad scheduling, deep stacks, and
+ * lockups) along with other things that don't fit well into existing LKDTM
+ * test source files.
+ */
+#include "lkdtm.h"
+#include <linux/list.h>
+#include <linux/sched.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/task_stack.h>
+#include <linux/uaccess.h>
+#include <linux/slab.h>
+
+#if IS_ENABLED(CONFIG_X86_32) && !IS_ENABLED(CONFIG_UML)
+#include <asm/desc.h>
+#endif
+
+struct lkdtm_list {
+	struct list_head node;
+};
+
+/*
+ * Make sure our attempts to over run the kernel stack doesn't trigger
+ * a compiler warning when CONFIG_FRAME_WARN is set. Then make sure we
+ * recurse past the end of THREAD_SIZE by default.
+ */
+#if defined(CONFIG_FRAME_WARN) && (CONFIG_FRAME_WARN > 0)
+#define REC_STACK_SIZE (_AC(CONFIG_FRAME_WARN, UL) / 2)
+#else
+#define REC_STACK_SIZE (THREAD_SIZE / 8)
+#endif
+#define REC_NUM_DEFAULT ((THREAD_SIZE / REC_STACK_SIZE) * 2)
+
+static int recur_count = REC_NUM_DEFAULT;
+
+static DEFINE_SPINLOCK(lock_me_up);
+
+/*
+ * Make sure compiler does not optimize this function or stack frame away:
+ * - function marked noinline
+ * - stack variables are marked volatile
+ * - stack variables are written (memset()) and read (pr_info())
+ * - function has external effects (pr_info())
+ * */
+static int noinline recursive_loop(int remaining)
+{
+	volatile char buf[REC_STACK_SIZE];
+
+	memset((void *)buf, remaining & 0xFF, sizeof(buf));
+	pr_info("loop %d/%d ...\n", (int)buf[remaining % sizeof(buf)],
+		recur_count);
+	if (!remaining)
+		return 0;
+	else
+		return recursive_loop(remaining - 1);
+}
+
+/* If the depth is negative, use the default, otherwise keep parameter. */
+void __init lkdtm_bugs_init(int *recur_param)
+{
+	if (*recur_param < 0)
+		*recur_param = recur_count;
+	else
+		recur_count = *recur_param;
+}
+
+void lkdtm_PANIC(void)
+{
+	panic("dumptest");
+}
+
+void lkdtm_BUG(void)
+{
+	BUG();
+}
+
+static int warn_counter;
+
+void lkdtm_WARNING(void)
+{
+	WARN_ON(++warn_counter);
+}
+
+void lkdtm_WARNING_MESSAGE(void)
+{
+	WARN(1, "Warning message trigger count: %d\n", ++warn_counter);
+}
+
+void lkdtm_EXCEPTION(void)
+{
+	*((volatile int *) 0) = 0;
+}
+
+void lkdtm_LOOP(void)
+{
+	for (;;)
+		;
+}
+
+void lkdtm_EXHAUST_STACK(void)
+{
+	pr_info("Calling function with %lu frame size to depth %d ...\n",
+		REC_STACK_SIZE, recur_count);
+	recursive_loop(recur_count);
+	pr_info("FAIL: survived without exhausting stack?!\n");
+}
+
+static noinline void __lkdtm_CORRUPT_STACK(void *stack)
+{
+	memset(stack, '\xff', 64);
+}
+
+/* This should trip the stack canary, not corrupt the return address. */
+noinline void lkdtm_CORRUPT_STACK(void)
+{
+	/* Use default char array length that triggers stack protection. */
+	char data[8] __aligned(sizeof(void *));
+
+	pr_info("Corrupting stack containing char array ...\n");
+	__lkdtm_CORRUPT_STACK((void *)&data);
+}
+
+/* Same as above but will only get a canary with -fstack-protector-strong */
+noinline void lkdtm_CORRUPT_STACK_STRONG(void)
+{
+	union {
+		unsigned short shorts[4];
+		unsigned long *ptr;
+	} data __aligned(sizeof(void *));
+
+	pr_info("Corrupting stack containing union ...\n");
+	__lkdtm_CORRUPT_STACK((void *)&data);
+}
+
+void lkdtm_UNALIGNED_LOAD_STORE_WRITE(void)
+{
+	static u8 data[5] __attribute__((aligned(4))) = {1, 2, 3, 4, 5};
+	u32 *p;
+	u32 val = 0x12345678;
+
+	p = (u32 *)(data + 1);
+	if (*p == 0)
+		val = 0x87654321;
+	*p = val;
+
+	if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS))
+		pr_err("XFAIL: arch has CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS\n");
+}
+
+void lkdtm_SOFTLOCKUP(void)
+{
+	preempt_disable();
+	for (;;)
+		cpu_relax();
+}
+
+void lkdtm_HARDLOCKUP(void)
+{
+	local_irq_disable();
+	for (;;)
+		cpu_relax();
+}
+
+void lkdtm_SPINLOCKUP(void)
+{
+	/* Must be called twice to trigger. */
+	spin_lock(&lock_me_up);
+	/* Let sparse know we intended to exit holding the lock. */
+	__release(&lock_me_up);
+}
+
+void lkdtm_HUNG_TASK(void)
+{
+	set_current_state(TASK_UNINTERRUPTIBLE);
+	schedule();
+}
+
+volatile unsigned int huge = INT_MAX - 2;
+volatile unsigned int ignored;
+
+void lkdtm_OVERFLOW_SIGNED(void)
+{
+	int value;
+
+	value = huge;
+	pr_info("Normal signed addition ...\n");
+	value += 1;
+	ignored = value;
+
+	pr_info("Overflowing signed addition ...\n");
+	value += 4;
+	ignored = value;
+}
+
+
+void lkdtm_OVERFLOW_UNSIGNED(void)
+{
+	unsigned int value;
+
+	value = huge;
+	pr_info("Normal unsigned addition ...\n");
+	value += 1;
+	ignored = value;
+
+	pr_info("Overflowing unsigned addition ...\n");
+	value += 4;
+	ignored = value;
+}
+
+/* Intentionally using old-style flex array definition of 1 byte. */
+struct array_bounds_flex_array {
+	int one;
+	int two;
+	char data[1];
+};
+
+struct array_bounds {
+	int one;
+	int two;
+	char data[8];
+	int three;
+};
+
+void lkdtm_ARRAY_BOUNDS(void)
+{
+	struct array_bounds_flex_array *not_checked;
+	struct array_bounds *checked;
+	volatile int i;
+
+	not_checked = kmalloc(sizeof(*not_checked) * 2, GFP_KERNEL);
+	checked = kmalloc(sizeof(*checked) * 2, GFP_KERNEL);
+	if (!not_checked || !checked) {
+		kfree(not_checked);
+		kfree(checked);
+		return;
+	}
+
+	pr_info("Array access within bounds ...\n");
+	/* For both, touch all bytes in the actual member size. */
+	for (i = 0; i < sizeof(checked->data); i++)
+		checked->data[i] = 'A';
+	/*
+	 * For the uninstrumented flex array member, also touch 1 byte
+	 * beyond to verify it is correctly uninstrumented.
+	 */
+	for (i = 0; i < sizeof(not_checked->data) + 1; i++)
+		not_checked->data[i] = 'A';
+
+	pr_info("Array access beyond bounds ...\n");
+	for (i = 0; i < sizeof(checked->data) + 1; i++)
+		checked->data[i] = 'B';
+
+	kfree(not_checked);
+	kfree(checked);
+	pr_err("FAIL: survived array bounds overflow!\n");
+}
+
+void lkdtm_CORRUPT_LIST_ADD(void)
+{
+	/*
+	 * Initially, an empty list via LIST_HEAD:
+	 *	test_head.next = &test_head
+	 *	test_head.prev = &test_head
+	 */
+	LIST_HEAD(test_head);
+	struct lkdtm_list good, bad;
+	void *target[2] = { };
+	void *redirection = &target;
+
+	pr_info("attempting good list addition\n");
+
+	/*
+	 * Adding to the list performs these actions:
+	 *	test_head.next->prev = &good.node
+	 *	good.node.next = test_head.next
+	 *	good.node.prev = test_head
+	 *	test_head.next = good.node
+	 */
+	list_add(&good.node, &test_head);
+
+	pr_info("attempting corrupted list addition\n");
+	/*
+	 * In simulating this "write what where" primitive, the "what" is
+	 * the address of &bad.node, and the "where" is the address held
+	 * by "redirection".
+	 */
+	test_head.next = redirection;
+	list_add(&bad.node, &test_head);
+
+	if (target[0] == NULL && target[1] == NULL)
+		pr_err("Overwrite did not happen, but no BUG?!\n");
+	else
+		pr_err("list_add() corruption not detected!\n");
+}
+
+void lkdtm_CORRUPT_LIST_DEL(void)
+{
+	LIST_HEAD(test_head);
+	struct lkdtm_list item;
+	void *target[2] = { };
+	void *redirection = &target;
+
+	list_add(&item.node, &test_head);
+
+	pr_info("attempting good list removal\n");
+	list_del(&item.node);
+
+	pr_info("attempting corrupted list removal\n");
+	list_add(&item.node, &test_head);
+
+	/* As with the list_add() test above, this corrupts "next". */
+	item.node.next = redirection;
+	list_del(&item.node);
+
+	if (target[0] == NULL && target[1] == NULL)
+		pr_err("Overwrite did not happen, but no BUG?!\n");
+	else
+		pr_err("list_del() corruption not detected!\n");
+}
+
+/* Test that VMAP_STACK is actually allocating with a leading guard page */
+void lkdtm_STACK_GUARD_PAGE_LEADING(void)
+{
+	const unsigned char *stack = task_stack_page(current);
+	const unsigned char *ptr = stack - 1;
+	volatile unsigned char byte;
+
+	pr_info("attempting bad read from page below current stack\n");
+
+	byte = *ptr;
+
+	pr_err("FAIL: accessed page before stack! (byte: %x)\n", byte);
+}
+
+/* Test that VMAP_STACK is actually allocating with a trailing guard page */
+void lkdtm_STACK_GUARD_PAGE_TRAILING(void)
+{
+	const unsigned char *stack = task_stack_page(current);
+	const unsigned char *ptr = stack + THREAD_SIZE;
+	volatile unsigned char byte;
+
+	pr_info("attempting bad read from page above current stack\n");
+
+	byte = *ptr;
+
+	pr_err("FAIL: accessed page after stack! (byte: %x)\n", byte);
+}
+
+void lkdtm_UNSET_SMEP(void)
+{
+#if IS_ENABLED(CONFIG_X86_64) && !IS_ENABLED(CONFIG_UML)
+#define MOV_CR4_DEPTH	64
+	void (*direct_write_cr4)(unsigned long val);
+	unsigned char *insn;
+	unsigned long cr4;
+	int i;
+
+	cr4 = native_read_cr4();
+
+	if ((cr4 & X86_CR4_SMEP) != X86_CR4_SMEP) {
+		pr_err("FAIL: SMEP not in use\n");
+		return;
+	}
+	cr4 &= ~(X86_CR4_SMEP);
+
+	pr_info("trying to clear SMEP normally\n");
+	native_write_cr4(cr4);
+	if (cr4 == native_read_cr4()) {
+		pr_err("FAIL: pinning SMEP failed!\n");
+		cr4 |= X86_CR4_SMEP;
+		pr_info("restoring SMEP\n");
+		native_write_cr4(cr4);
+		return;
+	}
+	pr_info("ok: SMEP did not get cleared\n");
+
+	/*
+	 * To test the post-write pinning verification we need to call
+	 * directly into the middle of native_write_cr4() where the
+	 * cr4 write happens, skipping any pinning. This searches for
+	 * the cr4 writing instruction.
+	 */
+	insn = (unsigned char *)native_write_cr4;
+	for (i = 0; i < MOV_CR4_DEPTH; i++) {
+		/* mov %rdi, %cr4 */
+		if (insn[i] == 0x0f && insn[i+1] == 0x22 && insn[i+2] == 0xe7)
+			break;
+		/* mov %rdi,%rax; mov %rax, %cr4 */
+		if (insn[i]   == 0x48 && insn[i+1] == 0x89 &&
+		    insn[i+2] == 0xf8 && insn[i+3] == 0x0f &&
+		    insn[i+4] == 0x22 && insn[i+5] == 0xe0)
+			break;
+	}
+	if (i >= MOV_CR4_DEPTH) {
+		pr_info("ok: cannot locate cr4 writing call gadget\n");
+		return;
+	}
+	direct_write_cr4 = (void *)(insn + i);
+
+	pr_info("trying to clear SMEP with call gadget\n");
+	direct_write_cr4(cr4);
+	if (native_read_cr4() & X86_CR4_SMEP) {
+		pr_info("ok: SMEP removal was reverted\n");
+	} else {
+		pr_err("FAIL: cleared SMEP not detected!\n");
+		cr4 |= X86_CR4_SMEP;
+		pr_info("restoring SMEP\n");
+		native_write_cr4(cr4);
+	}
+#else
+	pr_err("XFAIL: this test is x86_64-only\n");
+#endif
+}
+
+void lkdtm_DOUBLE_FAULT(void)
+{
+#if IS_ENABLED(CONFIG_X86_32) && !IS_ENABLED(CONFIG_UML)
+	/*
+	 * Trigger #DF by setting the stack limit to zero.  This clobbers
+	 * a GDT TLS slot, which is okay because the current task will die
+	 * anyway due to the double fault.
+	 */
+	struct desc_struct d = {
+		.type = 3,	/* expand-up, writable, accessed data */
+		.p = 1,		/* present */
+		.d = 1,		/* 32-bit */
+		.g = 0,		/* limit in bytes */
+		.s = 1,		/* not system */
+	};
+
+	local_irq_disable();
+	write_gdt_entry(get_cpu_gdt_rw(smp_processor_id()),
+			GDT_ENTRY_TLS_MIN, &d, DESCTYPE_S);
+
+	/*
+	 * Put our zero-limit segment in SS and then trigger a fault.  The
+	 * 4-byte access to (%esp) will fault with #SS, and the attempt to
+	 * deliver the fault will recursively cause #SS and result in #DF.
+	 * This whole process happens while NMIs and MCEs are blocked by the
+	 * MOV SS window.  This is nice because an NMI with an invalid SS
+	 * would also double-fault, resulting in the NMI or MCE being lost.
+	 */
+	asm volatile ("movw %0, %%ss; addl $0, (%%esp)" ::
+		      "r" ((unsigned short)(GDT_ENTRY_TLS_MIN << 3)));
+
+	pr_err("FAIL: tried to double fault but didn't die\n");
+#else
+	pr_err("XFAIL: this test is ia32-only\n");
+#endif
+}
+
+#ifdef CONFIG_ARM64
+static noinline void change_pac_parameters(void)
+{
+	if (IS_ENABLED(CONFIG_ARM64_PTR_AUTH)) {
+		/* Reset the keys of current task */
+		ptrauth_thread_init_kernel(current);
+		ptrauth_thread_switch_kernel(current);
+	}
+}
+#endif
+
+noinline void lkdtm_CORRUPT_PAC(void)
+{
+#ifdef CONFIG_ARM64
+#define CORRUPT_PAC_ITERATE	10
+	int i;
+
+	if (!IS_ENABLED(CONFIG_ARM64_PTR_AUTH))
+		pr_err("FAIL: kernel not built with CONFIG_ARM64_PTR_AUTH\n");
+
+	if (!system_supports_address_auth()) {
+		pr_err("FAIL: CPU lacks pointer authentication feature\n");
+		return;
+	}
+
+	pr_info("changing PAC parameters to force function return failure...\n");
+	/*
+	 * PAC is a hash value computed from input keys, return address and
+	 * stack pointer. As pac has fewer bits so there is a chance of
+	 * collision, so iterate few times to reduce the collision probability.
+	 */
+	for (i = 0; i < CORRUPT_PAC_ITERATE; i++)
+		change_pac_parameters();
+
+	pr_err("FAIL: survived PAC changes! Kernel may be unstable from here\n");
+#else
+	pr_err("XFAIL: this test is arm64-only\n");
+#endif
+}
diff --git a/drivers/misc/lkdtm/cfi.c b/drivers/misc/lkdtm/cfi.c
new file mode 100644
index 000000000..e73ebdbfa
--- /dev/null
+++ b/drivers/misc/lkdtm/cfi.c
@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This is for all the tests relating directly to Control Flow Integrity.
+ */
+#include "lkdtm.h"
+
+static int called_count;
+
+/* Function taking one argument, without a return value. */
+static noinline void lkdtm_increment_void(int *counter)
+{
+	(*counter)++;
+}
+
+/* Function taking one argument, returning int. */
+static noinline int lkdtm_increment_int(int *counter)
+{
+	(*counter)++;
+
+	return *counter;
+}
+/*
+ * This tries to call an indirect function with a mismatched prototype.
+ */
+void lkdtm_CFI_FORWARD_PROTO(void)
+{
+	/*
+	 * Matches lkdtm_increment_void()'s prototype, but not
+	 * lkdtm_increment_int()'s prototype.
+	 */
+	void (*func)(int *);
+
+	pr_info("Calling matched prototype ...\n");
+	func = lkdtm_increment_void;
+	func(&called_count);
+
+	pr_info("Calling mismatched prototype ...\n");
+	func = (void *)lkdtm_increment_int;
+	func(&called_count);
+
+	pr_info("Fail: survived mismatched prototype function call!\n");
+}
diff --git a/drivers/misc/lkdtm/core.c b/drivers/misc/lkdtm/core.c
new file mode 100644
index 000000000..32b3d7736
--- /dev/null
+++ b/drivers/misc/lkdtm/core.c
@@ -0,0 +1,489 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Linux Kernel Dump Test Module for testing kernel crashes conditions:
+ * induces system failures at predefined crashpoints and under predefined
+ * operational conditions in order to evaluate the reliability of kernel
+ * sanity checking and crash dumps obtained using different dumping
+ * solutions.
+ *
+ * Copyright (C) IBM Corporation, 2006
+ *
+ * Author: Ankita Garg <ankita@in.ibm.com>
+ *
+ * It is adapted from the Linux Kernel Dump Test Tool by
+ * Fernando Luis Vazquez Cao <http://lkdtt.sourceforge.net>
+ *
+ * Debugfs support added by Simon Kagstrom <simon.kagstrom@netinsight.net>
+ *
+ * See Documentation/fault-injection/provoke-crashes.rst for instructions
+ */
+#include "lkdtm.h"
+#include <linux/fs.h>
+#include <linux/module.h>
+#include <linux/buffer_head.h>
+#include <linux/kprobes.h>
+#include <linux/list.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/debugfs.h>
+
+#define DEFAULT_COUNT 10
+
+static int lkdtm_debugfs_open(struct inode *inode, struct file *file);
+static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
+		size_t count, loff_t *off);
+static ssize_t direct_entry(struct file *f, const char __user *user_buf,
+			    size_t count, loff_t *off);
+
+#ifdef CONFIG_KPROBES
+static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs);
+static ssize_t lkdtm_debugfs_entry(struct file *f,
+				   const char __user *user_buf,
+				   size_t count, loff_t *off);
+# define CRASHPOINT_KPROBE(_symbol)				\
+		.kprobe = {					\
+			.symbol_name = (_symbol),		\
+			.pre_handler = lkdtm_kprobe_handler,	\
+		},
+# define CRASHPOINT_WRITE(_symbol)				\
+		(_symbol) ? lkdtm_debugfs_entry : direct_entry
+#else
+# define CRASHPOINT_KPROBE(_symbol)
+# define CRASHPOINT_WRITE(_symbol)		direct_entry
+#endif
+
+/* Crash points */
+struct crashpoint {
+	const char *name;
+	const struct file_operations fops;
+	struct kprobe kprobe;
+};
+
+#define CRASHPOINT(_name, _symbol)				\
+	{							\
+		.name = _name,					\
+		.fops = {					\
+			.read	= lkdtm_debugfs_read,		\
+			.llseek	= generic_file_llseek,		\
+			.open	= lkdtm_debugfs_open,		\
+			.write	= CRASHPOINT_WRITE(_symbol)	\
+		},						\
+		CRASHPOINT_KPROBE(_symbol)			\
+	}
+
+/* Define the possible places where we can trigger a crash point. */
+static struct crashpoint crashpoints[] = {
+	CRASHPOINT("DIRECT",		 NULL),
+#ifdef CONFIG_KPROBES
+	CRASHPOINT("INT_HARDWARE_ENTRY", "do_IRQ"),
+	CRASHPOINT("INT_HW_IRQ_EN",	 "handle_irq_event"),
+	CRASHPOINT("INT_TASKLET_ENTRY",	 "tasklet_action"),
+	CRASHPOINT("FS_DEVRW",		 "ll_rw_block"),
+	CRASHPOINT("MEM_SWAPOUT",	 "shrink_inactive_list"),
+	CRASHPOINT("TIMERADD",		 "hrtimer_start"),
+	CRASHPOINT("SCSI_QUEUE_RQ",	 "scsi_queue_rq"),
+	CRASHPOINT("IDE_CORE_CP",	 "generic_ide_ioctl"),
+#endif
+};
+
+
+/* Crash types. */
+struct crashtype {
+	const char *name;
+	void (*func)(void);
+};
+
+#define CRASHTYPE(_name)			\
+	{					\
+		.name = __stringify(_name),	\
+		.func = lkdtm_ ## _name,	\
+	}
+
+/* Define the possible types of crashes that can be triggered. */
+static const struct crashtype crashtypes[] = {
+	CRASHTYPE(PANIC),
+	CRASHTYPE(BUG),
+	CRASHTYPE(WARNING),
+	CRASHTYPE(WARNING_MESSAGE),
+	CRASHTYPE(EXCEPTION),
+	CRASHTYPE(LOOP),
+	CRASHTYPE(EXHAUST_STACK),
+	CRASHTYPE(CORRUPT_STACK),
+	CRASHTYPE(CORRUPT_STACK_STRONG),
+	CRASHTYPE(CORRUPT_LIST_ADD),
+	CRASHTYPE(CORRUPT_LIST_DEL),
+	CRASHTYPE(STACK_GUARD_PAGE_LEADING),
+	CRASHTYPE(STACK_GUARD_PAGE_TRAILING),
+	CRASHTYPE(UNSET_SMEP),
+	CRASHTYPE(CORRUPT_PAC),
+	CRASHTYPE(UNALIGNED_LOAD_STORE_WRITE),
+	CRASHTYPE(OVERWRITE_ALLOCATION),
+	CRASHTYPE(WRITE_AFTER_FREE),
+	CRASHTYPE(READ_AFTER_FREE),
+	CRASHTYPE(WRITE_BUDDY_AFTER_FREE),
+	CRASHTYPE(READ_BUDDY_AFTER_FREE),
+	CRASHTYPE(SLAB_FREE_DOUBLE),
+	CRASHTYPE(SLAB_FREE_CROSS),
+	CRASHTYPE(SLAB_FREE_PAGE),
+	CRASHTYPE(SOFTLOCKUP),
+	CRASHTYPE(HARDLOCKUP),
+	CRASHTYPE(SPINLOCKUP),
+	CRASHTYPE(HUNG_TASK),
+	CRASHTYPE(OVERFLOW_SIGNED),
+	CRASHTYPE(OVERFLOW_UNSIGNED),
+	CRASHTYPE(ARRAY_BOUNDS),
+	CRASHTYPE(EXEC_DATA),
+	CRASHTYPE(EXEC_STACK),
+	CRASHTYPE(EXEC_KMALLOC),
+	CRASHTYPE(EXEC_VMALLOC),
+	CRASHTYPE(EXEC_RODATA),
+	CRASHTYPE(EXEC_USERSPACE),
+	CRASHTYPE(EXEC_NULL),
+	CRASHTYPE(ACCESS_USERSPACE),
+	CRASHTYPE(ACCESS_NULL),
+	CRASHTYPE(WRITE_RO),
+	CRASHTYPE(WRITE_RO_AFTER_INIT),
+	CRASHTYPE(WRITE_KERN),
+	CRASHTYPE(REFCOUNT_INC_OVERFLOW),
+	CRASHTYPE(REFCOUNT_ADD_OVERFLOW),
+	CRASHTYPE(REFCOUNT_INC_NOT_ZERO_OVERFLOW),
+	CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_OVERFLOW),
+	CRASHTYPE(REFCOUNT_DEC_ZERO),
+	CRASHTYPE(REFCOUNT_DEC_NEGATIVE),
+	CRASHTYPE(REFCOUNT_DEC_AND_TEST_NEGATIVE),
+	CRASHTYPE(REFCOUNT_SUB_AND_TEST_NEGATIVE),
+	CRASHTYPE(REFCOUNT_INC_ZERO),
+	CRASHTYPE(REFCOUNT_ADD_ZERO),
+	CRASHTYPE(REFCOUNT_INC_SATURATED),
+	CRASHTYPE(REFCOUNT_DEC_SATURATED),
+	CRASHTYPE(REFCOUNT_ADD_SATURATED),
+	CRASHTYPE(REFCOUNT_INC_NOT_ZERO_SATURATED),
+	CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_SATURATED),
+	CRASHTYPE(REFCOUNT_DEC_AND_TEST_SATURATED),
+	CRASHTYPE(REFCOUNT_SUB_AND_TEST_SATURATED),
+	CRASHTYPE(REFCOUNT_TIMING),
+	CRASHTYPE(ATOMIC_TIMING),
+	CRASHTYPE(USERCOPY_HEAP_SIZE_TO),
+	CRASHTYPE(USERCOPY_HEAP_SIZE_FROM),
+	CRASHTYPE(USERCOPY_HEAP_WHITELIST_TO),
+	CRASHTYPE(USERCOPY_HEAP_WHITELIST_FROM),
+	CRASHTYPE(USERCOPY_STACK_FRAME_TO),
+	CRASHTYPE(USERCOPY_STACK_FRAME_FROM),
+	CRASHTYPE(USERCOPY_STACK_BEYOND),
+	CRASHTYPE(USERCOPY_KERNEL),
+	CRASHTYPE(STACKLEAK_ERASING),
+	CRASHTYPE(CFI_FORWARD_PROTO),
+	CRASHTYPE(DOUBLE_FAULT),
+};
+
+
+/* Global kprobe entry and crashtype. */
+static struct kprobe *lkdtm_kprobe;
+static struct crashpoint *lkdtm_crashpoint;
+static const struct crashtype *lkdtm_crashtype;
+
+/* Module parameters */
+static int recur_count = -1;
+module_param(recur_count, int, 0644);
+MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test");
+
+static char* cpoint_name;
+module_param(cpoint_name, charp, 0444);
+MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
+
+static char* cpoint_type;
+module_param(cpoint_type, charp, 0444);
+MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
+				"hitting the crash point");
+
+static int cpoint_count = DEFAULT_COUNT;
+module_param(cpoint_count, int, 0644);
+MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
+				"crash point is to be hit to trigger action");
+
+
+/* Return the crashtype number or NULL if the name is invalid */
+static const struct crashtype *find_crashtype(const char *name)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
+		if (!strcmp(name, crashtypes[i].name))
+			return &crashtypes[i];
+	}
+
+	return NULL;
+}
+
+/*
+ * This is forced noinline just so it distinctly shows up in the stackdump
+ * which makes validation of expected lkdtm crashes easier.
+ */
+static noinline void lkdtm_do_action(const struct crashtype *crashtype)
+{
+	if (WARN_ON(!crashtype || !crashtype->func))
+		return;
+	crashtype->func();
+}
+
+static int lkdtm_register_cpoint(struct crashpoint *crashpoint,
+				 const struct crashtype *crashtype)
+{
+	int ret;
+
+	/* If this doesn't have a symbol, just call immediately. */
+	if (!crashpoint->kprobe.symbol_name) {
+		lkdtm_do_action(crashtype);
+		return 0;
+	}
+
+	if (lkdtm_kprobe != NULL)
+		unregister_kprobe(lkdtm_kprobe);
+
+	lkdtm_crashpoint = crashpoint;
+	lkdtm_crashtype = crashtype;
+	lkdtm_kprobe = &crashpoint->kprobe;
+	ret = register_kprobe(lkdtm_kprobe);
+	if (ret < 0) {
+		pr_info("Couldn't register kprobe %s\n",
+			crashpoint->kprobe.symbol_name);
+		lkdtm_kprobe = NULL;
+		lkdtm_crashpoint = NULL;
+		lkdtm_crashtype = NULL;
+	}
+
+	return ret;
+}
+
+#ifdef CONFIG_KPROBES
+/* Global crash counter and spinlock. */
+static int crash_count = DEFAULT_COUNT;
+static DEFINE_SPINLOCK(crash_count_lock);
+
+/* Called by kprobe entry points. */
+static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs)
+{
+	unsigned long flags;
+	bool do_it = false;
+
+	if (WARN_ON(!lkdtm_crashpoint || !lkdtm_crashtype))
+		return 0;
+
+	spin_lock_irqsave(&crash_count_lock, flags);
+	crash_count--;
+	pr_info("Crash point %s of type %s hit, trigger in %d rounds\n",
+		lkdtm_crashpoint->name, lkdtm_crashtype->name, crash_count);
+
+	if (crash_count == 0) {
+		do_it = true;
+		crash_count = cpoint_count;
+	}
+	spin_unlock_irqrestore(&crash_count_lock, flags);
+
+	if (do_it)
+		lkdtm_do_action(lkdtm_crashtype);
+
+	return 0;
+}
+
+static ssize_t lkdtm_debugfs_entry(struct file *f,
+				   const char __user *user_buf,
+				   size_t count, loff_t *off)
+{
+	struct crashpoint *crashpoint = file_inode(f)->i_private;
+	const struct crashtype *crashtype = NULL;
+	char *buf;
+	int err;
+
+	if (count >= PAGE_SIZE)
+		return -EINVAL;
+
+	buf = (char *)__get_free_page(GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+	if (copy_from_user(buf, user_buf, count)) {
+		free_page((unsigned long) buf);
+		return -EFAULT;
+	}
+	/* NULL-terminate and remove enter */
+	buf[count] = '\0';
+	strim(buf);
+
+	crashtype = find_crashtype(buf);
+	free_page((unsigned long)buf);
+
+	if (!crashtype)
+		return -EINVAL;
+
+	err = lkdtm_register_cpoint(crashpoint, crashtype);
+	if (err < 0)
+		return err;
+
+	*off += count;
+
+	return count;
+}
+#endif
+
+/* Generic read callback that just prints out the available crash types */
+static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
+		size_t count, loff_t *off)
+{
+	char *buf;
+	int i, n, out;
+
+	buf = (char *)__get_free_page(GFP_KERNEL);
+	if (buf == NULL)
+		return -ENOMEM;
+
+	n = scnprintf(buf, PAGE_SIZE, "Available crash types:\n");
+	for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
+		n += scnprintf(buf + n, PAGE_SIZE - n, "%s\n",
+			      crashtypes[i].name);
+	}
+	buf[n] = '\0';
+
+	out = simple_read_from_buffer(user_buf, count, off,
+				      buf, n);
+	free_page((unsigned long) buf);
+
+	return out;
+}
+
+static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
+{
+	return 0;
+}
+
+/* Special entry to just crash directly. Available without KPROBEs */
+static ssize_t direct_entry(struct file *f, const char __user *user_buf,
+		size_t count, loff_t *off)
+{
+	const struct crashtype *crashtype;
+	char *buf;
+
+	if (count >= PAGE_SIZE)
+		return -EINVAL;
+	if (count < 1)
+		return -EINVAL;
+
+	buf = (char *)__get_free_page(GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+	if (copy_from_user(buf, user_buf, count)) {
+		free_page((unsigned long) buf);
+		return -EFAULT;
+	}
+	/* NULL-terminate and remove enter */
+	buf[count] = '\0';
+	strim(buf);
+
+	crashtype = find_crashtype(buf);
+	free_page((unsigned long) buf);
+	if (!crashtype)
+		return -EINVAL;
+
+	pr_info("Performing direct entry %s\n", crashtype->name);
+	lkdtm_do_action(crashtype);
+	*off += count;
+
+	return count;
+}
+
+static struct dentry *lkdtm_debugfs_root;
+
+static int __init lkdtm_module_init(void)
+{
+	struct crashpoint *crashpoint = NULL;
+	const struct crashtype *crashtype = NULL;
+	int ret;
+	int i;
+
+	/* Neither or both of these need to be set */
+	if ((cpoint_type || cpoint_name) && !(cpoint_type && cpoint_name)) {
+		pr_err("Need both cpoint_type and cpoint_name or neither\n");
+		return -EINVAL;
+	}
+
+	if (cpoint_type) {
+		crashtype = find_crashtype(cpoint_type);
+		if (!crashtype) {
+			pr_err("Unknown crashtype '%s'\n", cpoint_type);
+			return -EINVAL;
+		}
+	}
+
+	if (cpoint_name) {
+		for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
+			if (!strcmp(cpoint_name, crashpoints[i].name))
+				crashpoint = &crashpoints[i];
+		}
+
+		/* Refuse unknown crashpoints. */
+		if (!crashpoint) {
+			pr_err("Invalid crashpoint %s\n", cpoint_name);
+			return -EINVAL;
+		}
+	}
+
+#ifdef CONFIG_KPROBES
+	/* Set crash count. */
+	crash_count = cpoint_count;
+#endif
+
+	/* Handle test-specific initialization. */
+	lkdtm_bugs_init(&recur_count);
+	lkdtm_perms_init();
+	lkdtm_usercopy_init();
+	lkdtm_heap_init();
+
+	/* Register debugfs interface */
+	lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
+
+	/* Install debugfs trigger files. */
+	for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
+		struct crashpoint *cur = &crashpoints[i];
+
+		debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root, cur,
+				    &cur->fops);
+	}
+
+	/* Install crashpoint if one was selected. */
+	if (crashpoint) {
+		ret = lkdtm_register_cpoint(crashpoint, crashtype);
+		if (ret < 0) {
+			pr_info("Invalid crashpoint %s\n", crashpoint->name);
+			goto out_err;
+		}
+		pr_info("Crash point %s of type %s registered\n",
+			crashpoint->name, cpoint_type);
+	} else {
+		pr_info("No crash points registered, enable through debugfs\n");
+	}
+
+	return 0;
+
+out_err:
+	debugfs_remove_recursive(lkdtm_debugfs_root);
+	return ret;
+}
+
+static void __exit lkdtm_module_exit(void)
+{
+	debugfs_remove_recursive(lkdtm_debugfs_root);
+
+	/* Handle test-specific clean-up. */
+	lkdtm_heap_exit();
+	lkdtm_usercopy_exit();
+
+	if (lkdtm_kprobe != NULL)
+		unregister_kprobe(lkdtm_kprobe);
+
+	pr_info("Crash point unregistered\n");
+}
+
+module_init(lkdtm_module_init);
+module_exit(lkdtm_module_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Kernel crash testing module");
diff --git a/drivers/misc/lkdtm/heap.c b/drivers/misc/lkdtm/heap.c
new file mode 100644
index 000000000..1323bc16f
--- /dev/null
+++ b/drivers/misc/lkdtm/heap.c
@@ -0,0 +1,221 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This is for all the tests relating directly to heap memory, including
+ * page allocation and slab allocations.
+ */
+#include "lkdtm.h"
+#include <linux/slab.h>
+#include <linux/sched.h>
+
+static struct kmem_cache *double_free_cache;
+static struct kmem_cache *a_cache;
+static struct kmem_cache *b_cache;
+
+/*
+ * This tries to stay within the next largest power-of-2 kmalloc cache
+ * to avoid actually overwriting anything important if it's not detected
+ * correctly.
+ */
+void lkdtm_OVERWRITE_ALLOCATION(void)
+{
+	size_t len = 1020;
+	u32 *data = kmalloc(len, GFP_KERNEL);
+	if (!data)
+		return;
+
+	data[1024 / sizeof(u32)] = 0x12345678;
+	kfree(data);
+}
+
+void lkdtm_WRITE_AFTER_FREE(void)
+{
+	int *base, *again;
+	size_t len = 1024;
+	/*
+	 * The slub allocator uses the first word to store the free
+	 * pointer in some configurations. Use the middle of the
+	 * allocation to avoid running into the freelist
+	 */
+	size_t offset = (len / sizeof(*base)) / 2;
+
+	base = kmalloc(len, GFP_KERNEL);
+	if (!base)
+		return;
+	pr_info("Allocated memory %p-%p\n", base, &base[offset * 2]);
+	pr_info("Attempting bad write to freed memory at %p\n",
+		&base[offset]);
+	kfree(base);
+	base[offset] = 0x0abcdef0;
+	/* Attempt to notice the overwrite. */
+	again = kmalloc(len, GFP_KERNEL);
+	kfree(again);
+	if (again != base)
+		pr_info("Hmm, didn't get the same memory range.\n");
+}
+
+void lkdtm_READ_AFTER_FREE(void)
+{
+	int *base, *val, saw;
+	size_t len = 1024;
+	/*
+	 * The slub allocator will use the either the first word or
+	 * the middle of the allocation to store the free pointer,
+	 * depending on configurations. Store in the second word to
+	 * avoid running into the freelist.
+	 */
+	size_t offset = sizeof(*base);
+
+	base = kmalloc(len, GFP_KERNEL);
+	if (!base) {
+		pr_info("Unable to allocate base memory.\n");
+		return;
+	}
+
+	val = kmalloc(len, GFP_KERNEL);
+	if (!val) {
+		pr_info("Unable to allocate val memory.\n");
+		kfree(base);
+		return;
+	}
+
+	*val = 0x12345678;
+	base[offset] = *val;
+	pr_info("Value in memory before free: %x\n", base[offset]);
+
+	kfree(base);
+
+	pr_info("Attempting bad read from freed memory\n");
+	saw = base[offset];
+	if (saw != *val) {
+		/* Good! Poisoning happened, so declare a win. */
+		pr_info("Memory correctly poisoned (%x)\n", saw);
+		BUG();
+	}
+	pr_info("Memory was not poisoned\n");
+
+	kfree(val);
+}
+
+void lkdtm_WRITE_BUDDY_AFTER_FREE(void)
+{
+	unsigned long p = __get_free_page(GFP_KERNEL);
+	if (!p) {
+		pr_info("Unable to allocate free page\n");
+		return;
+	}
+
+	pr_info("Writing to the buddy page before free\n");
+	memset((void *)p, 0x3, PAGE_SIZE);
+	free_page(p);
+	schedule();
+	pr_info("Attempting bad write to the buddy page after free\n");
+	memset((void *)p, 0x78, PAGE_SIZE);
+	/* Attempt to notice the overwrite. */
+	p = __get_free_page(GFP_KERNEL);
+	free_page(p);
+	schedule();
+}
+
+void lkdtm_READ_BUDDY_AFTER_FREE(void)
+{
+	unsigned long p = __get_free_page(GFP_KERNEL);
+	int saw, *val;
+	int *base;
+
+	if (!p) {
+		pr_info("Unable to allocate free page\n");
+		return;
+	}
+
+	val = kmalloc(1024, GFP_KERNEL);
+	if (!val) {
+		pr_info("Unable to allocate val memory.\n");
+		free_page(p);
+		return;
+	}
+
+	base = (int *)p;
+
+	*val = 0x12345678;
+	base[0] = *val;
+	pr_info("Value in memory before free: %x\n", base[0]);
+	free_page(p);
+	pr_info("Attempting to read from freed memory\n");
+	saw = base[0];
+	if (saw != *val) {
+		/* Good! Poisoning happened, so declare a win. */
+		pr_info("Memory correctly poisoned (%x)\n", saw);
+		BUG();
+	}
+	pr_info("Buddy page was not poisoned\n");
+
+	kfree(val);
+}
+
+void lkdtm_SLAB_FREE_DOUBLE(void)
+{
+	int *val;
+
+	val = kmem_cache_alloc(double_free_cache, GFP_KERNEL);
+	if (!val) {
+		pr_info("Unable to allocate double_free_cache memory.\n");
+		return;
+	}
+
+	/* Just make sure we got real memory. */
+	*val = 0x12345678;
+	pr_info("Attempting double slab free ...\n");
+	kmem_cache_free(double_free_cache, val);
+	kmem_cache_free(double_free_cache, val);
+}
+
+void lkdtm_SLAB_FREE_CROSS(void)
+{
+	int *val;
+
+	val = kmem_cache_alloc(a_cache, GFP_KERNEL);
+	if (!val) {
+		pr_info("Unable to allocate a_cache memory.\n");
+		return;
+	}
+
+	/* Just make sure we got real memory. */
+	*val = 0x12345679;
+	pr_info("Attempting cross-cache slab free ...\n");
+	kmem_cache_free(b_cache, val);
+}
+
+void lkdtm_SLAB_FREE_PAGE(void)
+{
+	unsigned long p = __get_free_page(GFP_KERNEL);
+
+	pr_info("Attempting non-Slab slab free ...\n");
+	kmem_cache_free(NULL, (void *)p);
+	free_page(p);
+}
+
+/*
+ * We have constructors to keep the caches distinctly separated without
+ * needing to boot with "slab_nomerge".
+ */
+static void ctor_double_free(void *region)
+{ }
+static void ctor_a(void *region)
+{ }
+static void ctor_b(void *region)
+{ }
+
+void __init lkdtm_heap_init(void)
+{
+	double_free_cache = kmem_cache_create("lkdtm-heap-double_free",
+					      64, 0, 0, ctor_double_free);
+	a_cache = kmem_cache_create("lkdtm-heap-a", 64, 0, 0, ctor_a);
+	b_cache = kmem_cache_create("lkdtm-heap-b", 64, 0, 0, ctor_b);
+}
+
+void __exit lkdtm_heap_exit(void)
+{
+	kmem_cache_destroy(double_free_cache);
+	kmem_cache_destroy(a_cache);
+	kmem_cache_destroy(b_cache);
+}
diff --git a/drivers/misc/lkdtm/lkdtm.h b/drivers/misc/lkdtm/lkdtm.h
new file mode 100644
index 000000000..6dec4c9b4
--- /dev/null
+++ b/drivers/misc/lkdtm/lkdtm.h
@@ -0,0 +1,105 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __LKDTM_H
+#define __LKDTM_H
+
+#define pr_fmt(fmt) "lkdtm: " fmt
+
+#include <linux/kernel.h>
+
+/* lkdtm_bugs.c */
+void __init lkdtm_bugs_init(int *recur_param);
+void lkdtm_PANIC(void);
+void lkdtm_BUG(void);
+void lkdtm_WARNING(void);
+void lkdtm_WARNING_MESSAGE(void);
+void lkdtm_EXCEPTION(void);
+void lkdtm_LOOP(void);
+void lkdtm_EXHAUST_STACK(void);
+void lkdtm_CORRUPT_STACK(void);
+void lkdtm_CORRUPT_STACK_STRONG(void);
+void lkdtm_UNALIGNED_LOAD_STORE_WRITE(void);
+void lkdtm_SOFTLOCKUP(void);
+void lkdtm_HARDLOCKUP(void);
+void lkdtm_SPINLOCKUP(void);
+void lkdtm_HUNG_TASK(void);
+void lkdtm_OVERFLOW_SIGNED(void);
+void lkdtm_OVERFLOW_UNSIGNED(void);
+void lkdtm_ARRAY_BOUNDS(void);
+void lkdtm_CORRUPT_LIST_ADD(void);
+void lkdtm_CORRUPT_LIST_DEL(void);
+void lkdtm_STACK_GUARD_PAGE_LEADING(void);
+void lkdtm_STACK_GUARD_PAGE_TRAILING(void);
+void lkdtm_UNSET_SMEP(void);
+void lkdtm_DOUBLE_FAULT(void);
+void lkdtm_CORRUPT_PAC(void);
+
+/* lkdtm_heap.c */
+void __init lkdtm_heap_init(void);
+void __exit lkdtm_heap_exit(void);
+void lkdtm_OVERWRITE_ALLOCATION(void);
+void lkdtm_WRITE_AFTER_FREE(void);
+void lkdtm_READ_AFTER_FREE(void);
+void lkdtm_WRITE_BUDDY_AFTER_FREE(void);
+void lkdtm_READ_BUDDY_AFTER_FREE(void);
+void lkdtm_SLAB_FREE_DOUBLE(void);
+void lkdtm_SLAB_FREE_CROSS(void);
+void lkdtm_SLAB_FREE_PAGE(void);
+
+/* lkdtm_perms.c */
+void __init lkdtm_perms_init(void);
+void lkdtm_WRITE_RO(void);
+void lkdtm_WRITE_RO_AFTER_INIT(void);
+void lkdtm_WRITE_KERN(void);
+void lkdtm_EXEC_DATA(void);
+void lkdtm_EXEC_STACK(void);
+void lkdtm_EXEC_KMALLOC(void);
+void lkdtm_EXEC_VMALLOC(void);
+void lkdtm_EXEC_RODATA(void);
+void lkdtm_EXEC_USERSPACE(void);
+void lkdtm_EXEC_NULL(void);
+void lkdtm_ACCESS_USERSPACE(void);
+void lkdtm_ACCESS_NULL(void);
+
+/* lkdtm_refcount.c */
+void lkdtm_REFCOUNT_INC_OVERFLOW(void);
+void lkdtm_REFCOUNT_ADD_OVERFLOW(void);
+void lkdtm_REFCOUNT_INC_NOT_ZERO_OVERFLOW(void);
+void lkdtm_REFCOUNT_ADD_NOT_ZERO_OVERFLOW(void);
+void lkdtm_REFCOUNT_DEC_ZERO(void);
+void lkdtm_REFCOUNT_DEC_NEGATIVE(void);
+void lkdtm_REFCOUNT_DEC_AND_TEST_NEGATIVE(void);
+void lkdtm_REFCOUNT_SUB_AND_TEST_NEGATIVE(void);
+void lkdtm_REFCOUNT_INC_ZERO(void);
+void lkdtm_REFCOUNT_ADD_ZERO(void);
+void lkdtm_REFCOUNT_INC_SATURATED(void);
+void lkdtm_REFCOUNT_DEC_SATURATED(void);
+void lkdtm_REFCOUNT_ADD_SATURATED(void);
+void lkdtm_REFCOUNT_INC_NOT_ZERO_SATURATED(void);
+void lkdtm_REFCOUNT_ADD_NOT_ZERO_SATURATED(void);
+void lkdtm_REFCOUNT_DEC_AND_TEST_SATURATED(void);
+void lkdtm_REFCOUNT_SUB_AND_TEST_SATURATED(void);
+void lkdtm_REFCOUNT_TIMING(void);
+void lkdtm_ATOMIC_TIMING(void);
+
+/* lkdtm_rodata.c */
+void lkdtm_rodata_do_nothing(void);
+
+/* lkdtm_usercopy.c */
+void __init lkdtm_usercopy_init(void);
+void __exit lkdtm_usercopy_exit(void);
+void lkdtm_USERCOPY_HEAP_SIZE_TO(void);
+void lkdtm_USERCOPY_HEAP_SIZE_FROM(void);
+void lkdtm_USERCOPY_HEAP_WHITELIST_TO(void);
+void lkdtm_USERCOPY_HEAP_WHITELIST_FROM(void);
+void lkdtm_USERCOPY_STACK_FRAME_TO(void);
+void lkdtm_USERCOPY_STACK_FRAME_FROM(void);
+void lkdtm_USERCOPY_STACK_BEYOND(void);
+void lkdtm_USERCOPY_KERNEL(void);
+
+/* lkdtm_stackleak.c */
+void lkdtm_STACKLEAK_ERASING(void);
+
+/* cfi.c */
+void lkdtm_CFI_FORWARD_PROTO(void);
+
+#endif
diff --git a/drivers/misc/lkdtm/perms.c b/drivers/misc/lkdtm/perms.c
new file mode 100644
index 000000000..2dede2ef6
--- /dev/null
+++ b/drivers/misc/lkdtm/perms.c
@@ -0,0 +1,229 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This is for all the tests related to validating kernel memory
+ * permissions: non-executable regions, non-writable regions, and
+ * even non-readable regions.
+ */
+#include "lkdtm.h"
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/mman.h>
+#include <linux/uaccess.h>
+#include <asm/cacheflush.h>
+
+/* Whether or not to fill the target memory area with do_nothing(). */
+#define CODE_WRITE	true
+#define CODE_AS_IS	false
+
+/* How many bytes to copy to be sure we've copied enough of do_nothing(). */
+#define EXEC_SIZE 64
+
+/* This is non-const, so it will end up in the .data section. */
+static u8 data_area[EXEC_SIZE];
+
+/* This is cost, so it will end up in the .rodata section. */
+static const unsigned long rodata = 0xAA55AA55;
+
+/* This is marked __ro_after_init, so it should ultimately be .rodata. */
+static unsigned long ro_after_init __ro_after_init = 0x55AA5500;
+
+/*
+ * This just returns to the caller. It is designed to be copied into
+ * non-executable memory regions.
+ */
+static void do_nothing(void)
+{
+	return;
+}
+
+/* Must immediately follow do_nothing for size calculuations to work out. */
+static void do_overwritten(void)
+{
+	pr_info("do_overwritten wasn't overwritten!\n");
+	return;
+}
+
+static noinline void execute_location(void *dst, bool write)
+{
+	void (*func)(void) = dst;
+
+	pr_info("attempting ok execution at %px\n", do_nothing);
+	do_nothing();
+
+	if (write == CODE_WRITE) {
+		memcpy(dst, do_nothing, EXEC_SIZE);
+		flush_icache_range((unsigned long)dst,
+				   (unsigned long)dst + EXEC_SIZE);
+	}
+	pr_info("attempting bad execution at %px\n", func);
+	func();
+	pr_err("FAIL: func returned\n");
+}
+
+static void execute_user_location(void *dst)
+{
+	int copied;
+
+	/* Intentionally crossing kernel/user memory boundary. */
+	void (*func)(void) = dst;
+
+	pr_info("attempting ok execution at %px\n", do_nothing);
+	do_nothing();
+
+	copied = access_process_vm(current, (unsigned long)dst, do_nothing,
+				   EXEC_SIZE, FOLL_WRITE);
+	if (copied < EXEC_SIZE)
+		return;
+	pr_info("attempting bad execution at %px\n", func);
+	func();
+	pr_err("FAIL: func returned\n");
+}
+
+void lkdtm_WRITE_RO(void)
+{
+	/* Explicitly cast away "const" for the test and make volatile. */
+	volatile unsigned long *ptr = (unsigned long *)&rodata;
+
+	pr_info("attempting bad rodata write at %px\n", ptr);
+	*ptr ^= 0xabcd1234;
+	pr_err("FAIL: survived bad write\n");
+}
+
+void lkdtm_WRITE_RO_AFTER_INIT(void)
+{
+	volatile unsigned long *ptr = &ro_after_init;
+
+	/*
+	 * Verify we were written to during init. Since an Oops
+	 * is considered a "success", a failure is to just skip the
+	 * real test.
+	 */
+	if ((*ptr & 0xAA) != 0xAA) {
+		pr_info("%p was NOT written during init!?\n", ptr);
+		return;
+	}
+
+	pr_info("attempting bad ro_after_init write at %px\n", ptr);
+	*ptr ^= 0xabcd1234;
+	pr_err("FAIL: survived bad write\n");
+}
+
+void lkdtm_WRITE_KERN(void)
+{
+	size_t size;
+	volatile unsigned char *ptr;
+
+	size = (unsigned long)do_overwritten - (unsigned long)do_nothing;
+	ptr = (unsigned char *)do_overwritten;
+
+	pr_info("attempting bad %zu byte write at %px\n", size, ptr);
+	memcpy((void *)ptr, (unsigned char *)do_nothing, size);
+	flush_icache_range((unsigned long)ptr, (unsigned long)(ptr + size));
+	pr_err("FAIL: survived bad write\n");
+
+	do_overwritten();
+}
+
+void lkdtm_EXEC_DATA(void)
+{
+	execute_location(data_area, CODE_WRITE);
+}
+
+void lkdtm_EXEC_STACK(void)
+{
+	u8 stack_area[EXEC_SIZE];
+	execute_location(stack_area, CODE_WRITE);
+}
+
+void lkdtm_EXEC_KMALLOC(void)
+{
+	u32 *kmalloc_area = kmalloc(EXEC_SIZE, GFP_KERNEL);
+	execute_location(kmalloc_area, CODE_WRITE);
+	kfree(kmalloc_area);
+}
+
+void lkdtm_EXEC_VMALLOC(void)
+{
+	u32 *vmalloc_area = vmalloc(EXEC_SIZE);
+	execute_location(vmalloc_area, CODE_WRITE);
+	vfree(vmalloc_area);
+}
+
+void lkdtm_EXEC_RODATA(void)
+{
+	execute_location(lkdtm_rodata_do_nothing, CODE_AS_IS);
+}
+
+void lkdtm_EXEC_USERSPACE(void)
+{
+	unsigned long user_addr;
+
+	user_addr = vm_mmap(NULL, 0, PAGE_SIZE,
+			    PROT_READ | PROT_WRITE | PROT_EXEC,
+			    MAP_ANONYMOUS | MAP_PRIVATE, 0);
+	if (user_addr >= TASK_SIZE) {
+		pr_warn("Failed to allocate user memory\n");
+		return;
+	}
+	execute_user_location((void *)user_addr);
+	vm_munmap(user_addr, PAGE_SIZE);
+}
+
+void lkdtm_EXEC_NULL(void)
+{
+	execute_location(NULL, CODE_AS_IS);
+}
+
+void lkdtm_ACCESS_USERSPACE(void)
+{
+	unsigned long user_addr, tmp = 0;
+	unsigned long *ptr;
+
+	user_addr = vm_mmap(NULL, 0, PAGE_SIZE,
+			    PROT_READ | PROT_WRITE | PROT_EXEC,
+			    MAP_ANONYMOUS | MAP_PRIVATE, 0);
+	if (user_addr >= TASK_SIZE) {
+		pr_warn("Failed to allocate user memory\n");
+		return;
+	}
+
+	if (copy_to_user((void __user *)user_addr, &tmp, sizeof(tmp))) {
+		pr_warn("copy_to_user failed\n");
+		vm_munmap(user_addr, PAGE_SIZE);
+		return;
+	}
+
+	ptr = (unsigned long *)user_addr;
+
+	pr_info("attempting bad read at %px\n", ptr);
+	tmp = *ptr;
+	tmp += 0xc0dec0de;
+	pr_err("FAIL: survived bad read\n");
+
+	pr_info("attempting bad write at %px\n", ptr);
+	*ptr = tmp;
+	pr_err("FAIL: survived bad write\n");
+
+	vm_munmap(user_addr, PAGE_SIZE);
+}
+
+void lkdtm_ACCESS_NULL(void)
+{
+	unsigned long tmp;
+	volatile unsigned long *ptr = (unsigned long *)NULL;
+
+	pr_info("attempting bad read at %px\n", ptr);
+	tmp = *ptr;
+	tmp += 0xc0dec0de;
+	pr_err("FAIL: survived bad read\n");
+
+	pr_info("attempting bad write at %px\n", ptr);
+	*ptr = tmp;
+	pr_err("FAIL: survived bad write\n");
+}
+
+void __init lkdtm_perms_init(void)
+{
+	/* Make sure we can write to __ro_after_init values during __init */
+	ro_after_init |= 0xAA;
+}
diff --git a/drivers/misc/lkdtm/refcount.c b/drivers/misc/lkdtm/refcount.c
new file mode 100644
index 000000000..de7c5ab52
--- /dev/null
+++ b/drivers/misc/lkdtm/refcount.c
@@ -0,0 +1,392 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This is for all the tests related to refcount bugs (e.g. overflow,
+ * underflow, reaching zero untested, etc).
+ */
+#include "lkdtm.h"
+#include <linux/refcount.h>
+
+static void overflow_check(refcount_t *ref)
+{
+	switch (refcount_read(ref)) {
+	case REFCOUNT_SATURATED:
+		pr_info("Overflow detected: saturated\n");
+		break;
+	case REFCOUNT_MAX:
+		pr_warn("Overflow detected: unsafely reset to max\n");
+		break;
+	default:
+		pr_err("Fail: refcount wrapped to %d\n", refcount_read(ref));
+	}
+}
+
+/*
+ * A refcount_inc() above the maximum value of the refcount implementation,
+ * should at least saturate, and at most also WARN.
+ */
+void lkdtm_REFCOUNT_INC_OVERFLOW(void)
+{
+	refcount_t over = REFCOUNT_INIT(REFCOUNT_MAX - 1);
+
+	pr_info("attempting good refcount_inc() without overflow\n");
+	refcount_dec(&over);
+	refcount_inc(&over);
+
+	pr_info("attempting bad refcount_inc() overflow\n");
+	refcount_inc(&over);
+	refcount_inc(&over);
+
+	overflow_check(&over);
+}
+
+/* refcount_add() should behave just like refcount_inc() above. */
+void lkdtm_REFCOUNT_ADD_OVERFLOW(void)
+{
+	refcount_t over = REFCOUNT_INIT(REFCOUNT_MAX - 1);
+
+	pr_info("attempting good refcount_add() without overflow\n");
+	refcount_dec(&over);
+	refcount_dec(&over);
+	refcount_dec(&over);
+	refcount_dec(&over);
+	refcount_add(4, &over);
+
+	pr_info("attempting bad refcount_add() overflow\n");
+	refcount_add(4, &over);
+
+	overflow_check(&over);
+}
+
+/* refcount_inc_not_zero() should behave just like refcount_inc() above. */
+void lkdtm_REFCOUNT_INC_NOT_ZERO_OVERFLOW(void)
+{
+	refcount_t over = REFCOUNT_INIT(REFCOUNT_MAX);
+
+	pr_info("attempting bad refcount_inc_not_zero() overflow\n");
+	if (!refcount_inc_not_zero(&over))
+		pr_warn("Weird: refcount_inc_not_zero() reported zero\n");
+
+	overflow_check(&over);
+}
+
+/* refcount_add_not_zero() should behave just like refcount_inc() above. */
+void lkdtm_REFCOUNT_ADD_NOT_ZERO_OVERFLOW(void)
+{
+	refcount_t over = REFCOUNT_INIT(REFCOUNT_MAX);
+
+	pr_info("attempting bad refcount_add_not_zero() overflow\n");
+	if (!refcount_add_not_zero(6, &over))
+		pr_warn("Weird: refcount_add_not_zero() reported zero\n");
+
+	overflow_check(&over);
+}
+
+static void check_zero(refcount_t *ref)
+{
+	switch (refcount_read(ref)) {
+	case REFCOUNT_SATURATED:
+		pr_info("Zero detected: saturated\n");
+		break;
+	case REFCOUNT_MAX:
+		pr_warn("Zero detected: unsafely reset to max\n");
+		break;
+	case 0:
+		pr_warn("Still at zero: refcount_inc/add() must not inc-from-0\n");
+		break;
+	default:
+		pr_err("Fail: refcount went crazy: %d\n", refcount_read(ref));
+	}
+}
+
+/*
+ * A refcount_dec(), as opposed to a refcount_dec_and_test(), when it hits
+ * zero it should either saturate (when inc-from-zero isn't protected)
+ * or stay at zero (when inc-from-zero is protected) and should WARN for both.
+ */
+void lkdtm_REFCOUNT_DEC_ZERO(void)
+{
+	refcount_t zero = REFCOUNT_INIT(2);
+
+	pr_info("attempting good refcount_dec()\n");
+	refcount_dec(&zero);
+
+	pr_info("attempting bad refcount_dec() to zero\n");
+	refcount_dec(&zero);
+
+	check_zero(&zero);
+}
+
+static void check_negative(refcount_t *ref, int start)
+{
+	/*
+	 * refcount_t refuses to move a refcount at all on an
+	 * over-sub, so we have to track our starting position instead of
+	 * looking only at zero-pinning.
+	 */
+	if (refcount_read(ref) == start) {
+		pr_warn("Still at %d: refcount_inc/add() must not inc-from-0\n",
+			start);
+		return;
+	}
+
+	switch (refcount_read(ref)) {
+	case REFCOUNT_SATURATED:
+		pr_info("Negative detected: saturated\n");
+		break;
+	case REFCOUNT_MAX:
+		pr_warn("Negative detected: unsafely reset to max\n");
+		break;
+	default:
+		pr_err("Fail: refcount went crazy: %d\n", refcount_read(ref));
+	}
+}
+
+/* A refcount_dec() going negative should saturate and may WARN. */
+void lkdtm_REFCOUNT_DEC_NEGATIVE(void)
+{
+	refcount_t neg = REFCOUNT_INIT(0);
+
+	pr_info("attempting bad refcount_dec() below zero\n");
+	refcount_dec(&neg);
+
+	check_negative(&neg, 0);
+}
+
+/*
+ * A refcount_dec_and_test() should act like refcount_dec() above when
+ * going negative.
+ */
+void lkdtm_REFCOUNT_DEC_AND_TEST_NEGATIVE(void)
+{
+	refcount_t neg = REFCOUNT_INIT(0);
+
+	pr_info("attempting bad refcount_dec_and_test() below zero\n");
+	if (refcount_dec_and_test(&neg))
+		pr_warn("Weird: refcount_dec_and_test() reported zero\n");
+
+	check_negative(&neg, 0);
+}
+
+/*
+ * A refcount_sub_and_test() should act like refcount_dec_and_test()
+ * above when going negative.
+ */
+void lkdtm_REFCOUNT_SUB_AND_TEST_NEGATIVE(void)
+{
+	refcount_t neg = REFCOUNT_INIT(3);
+
+	pr_info("attempting bad refcount_sub_and_test() below zero\n");
+	if (refcount_sub_and_test(5, &neg))
+		pr_warn("Weird: refcount_sub_and_test() reported zero\n");
+
+	check_negative(&neg, 3);
+}
+
+static void check_from_zero(refcount_t *ref)
+{
+	switch (refcount_read(ref)) {
+	case 0:
+		pr_info("Zero detected: stayed at zero\n");
+		break;
+	case REFCOUNT_SATURATED:
+		pr_info("Zero detected: saturated\n");
+		break;
+	case REFCOUNT_MAX:
+		pr_warn("Zero detected: unsafely reset to max\n");
+		break;
+	default:
+		pr_info("Fail: zero not detected, incremented to %d\n",
+			refcount_read(ref));
+	}
+}
+
+/*
+ * A refcount_inc() from zero should pin to zero or saturate and may WARN.
+ */
+void lkdtm_REFCOUNT_INC_ZERO(void)
+{
+	refcount_t zero = REFCOUNT_INIT(0);
+
+	pr_info("attempting safe refcount_inc_not_zero() from zero\n");
+	if (!refcount_inc_not_zero(&zero)) {
+		pr_info("Good: zero detected\n");
+		if (refcount_read(&zero) == 0)
+			pr_info("Correctly stayed at zero\n");
+		else
+			pr_err("Fail: refcount went past zero!\n");
+	} else {
+		pr_err("Fail: Zero not detected!?\n");
+	}
+
+	pr_info("attempting bad refcount_inc() from zero\n");
+	refcount_inc(&zero);
+
+	check_from_zero(&zero);
+}
+
+/*
+ * A refcount_add() should act like refcount_inc() above when starting
+ * at zero.
+ */
+void lkdtm_REFCOUNT_ADD_ZERO(void)
+{
+	refcount_t zero = REFCOUNT_INIT(0);
+
+	pr_info("attempting safe refcount_add_not_zero() from zero\n");
+	if (!refcount_add_not_zero(3, &zero)) {
+		pr_info("Good: zero detected\n");
+		if (refcount_read(&zero) == 0)
+			pr_info("Correctly stayed at zero\n");
+		else
+			pr_err("Fail: refcount went past zero\n");
+	} else {
+		pr_err("Fail: Zero not detected!?\n");
+	}
+
+	pr_info("attempting bad refcount_add() from zero\n");
+	refcount_add(3, &zero);
+
+	check_from_zero(&zero);
+}
+
+static void check_saturated(refcount_t *ref)
+{
+	switch (refcount_read(ref)) {
+	case REFCOUNT_SATURATED:
+		pr_info("Saturation detected: still saturated\n");
+		break;
+	case REFCOUNT_MAX:
+		pr_warn("Saturation detected: unsafely reset to max\n");
+		break;
+	default:
+		pr_err("Fail: refcount went crazy: %d\n", refcount_read(ref));
+	}
+}
+
+/*
+ * A refcount_inc() from a saturated value should at most warn about
+ * being saturated already.
+ */
+void lkdtm_REFCOUNT_INC_SATURATED(void)
+{
+	refcount_t sat = REFCOUNT_INIT(REFCOUNT_SATURATED);
+
+	pr_info("attempting bad refcount_inc() from saturated\n");
+	refcount_inc(&sat);
+
+	check_saturated(&sat);
+}
+
+/* Should act like refcount_inc() above from saturated. */
+void lkdtm_REFCOUNT_DEC_SATURATED(void)
+{
+	refcount_t sat = REFCOUNT_INIT(REFCOUNT_SATURATED);
+
+	pr_info("attempting bad refcount_dec() from saturated\n");
+	refcount_dec(&sat);
+
+	check_saturated(&sat);
+}
+
+/* Should act like refcount_inc() above from saturated. */
+void lkdtm_REFCOUNT_ADD_SATURATED(void)
+{
+	refcount_t sat = REFCOUNT_INIT(REFCOUNT_SATURATED);
+
+	pr_info("attempting bad refcount_dec() from saturated\n");
+	refcount_add(8, &sat);
+
+	check_saturated(&sat);
+}
+
+/* Should act like refcount_inc() above from saturated. */
+void lkdtm_REFCOUNT_INC_NOT_ZERO_SATURATED(void)
+{
+	refcount_t sat = REFCOUNT_INIT(REFCOUNT_SATURATED);
+
+	pr_info("attempting bad refcount_inc_not_zero() from saturated\n");
+	if (!refcount_inc_not_zero(&sat))
+		pr_warn("Weird: refcount_inc_not_zero() reported zero\n");
+
+	check_saturated(&sat);
+}
+
+/* Should act like refcount_inc() above from saturated. */
+void lkdtm_REFCOUNT_ADD_NOT_ZERO_SATURATED(void)
+{
+	refcount_t sat = REFCOUNT_INIT(REFCOUNT_SATURATED);
+
+	pr_info("attempting bad refcount_add_not_zero() from saturated\n");
+	if (!refcount_add_not_zero(7, &sat))
+		pr_warn("Weird: refcount_add_not_zero() reported zero\n");
+
+	check_saturated(&sat);
+}
+
+/* Should act like refcount_inc() above from saturated. */
+void lkdtm_REFCOUNT_DEC_AND_TEST_SATURATED(void)
+{
+	refcount_t sat = REFCOUNT_INIT(REFCOUNT_SATURATED);
+
+	pr_info("attempting bad refcount_dec_and_test() from saturated\n");
+	if (refcount_dec_and_test(&sat))
+		pr_warn("Weird: refcount_dec_and_test() reported zero\n");
+
+	check_saturated(&sat);
+}
+
+/* Should act like refcount_inc() above from saturated. */
+void lkdtm_REFCOUNT_SUB_AND_TEST_SATURATED(void)
+{
+	refcount_t sat = REFCOUNT_INIT(REFCOUNT_SATURATED);
+
+	pr_info("attempting bad refcount_sub_and_test() from saturated\n");
+	if (refcount_sub_and_test(8, &sat))
+		pr_warn("Weird: refcount_sub_and_test() reported zero\n");
+
+	check_saturated(&sat);
+}
+
+/* Used to time the existing atomic_t when used for reference counting */
+void lkdtm_ATOMIC_TIMING(void)
+{
+	unsigned int i;
+	atomic_t count = ATOMIC_INIT(1);
+
+	for (i = 0; i < INT_MAX - 1; i++)
+		atomic_inc(&count);
+
+	for (i = INT_MAX; i > 0; i--)
+		if (atomic_dec_and_test(&count))
+			break;
+
+	if (i != 1)
+		pr_err("atomic timing: out of sync up/down cycle: %u\n", i - 1);
+	else
+		pr_info("atomic timing: done\n");
+}
+
+/*
+ * This can be compared to ATOMIC_TIMING when implementing fast refcount
+ * protections. Looking at the number of CPU cycles tells the real story
+ * about performance. For example:
+ *    cd /sys/kernel/debug/provoke-crash
+ *    perf stat -B -- cat <(echo REFCOUNT_TIMING) > DIRECT
+ */
+void lkdtm_REFCOUNT_TIMING(void)
+{
+	unsigned int i;
+	refcount_t count = REFCOUNT_INIT(1);
+
+	for (i = 0; i < INT_MAX - 1; i++)
+		refcount_inc(&count);
+
+	for (i = INT_MAX; i > 0; i--)
+		if (refcount_dec_and_test(&count))
+			break;
+
+	if (i != 1)
+		pr_err("refcount: out of sync up/down cycle: %u\n", i - 1);
+	else
+		pr_info("refcount timing: done\n");
+}
diff --git a/drivers/misc/lkdtm/rodata.c b/drivers/misc/lkdtm/rodata.c
new file mode 100644
index 000000000..baacb876d
--- /dev/null
+++ b/drivers/misc/lkdtm/rodata.c
@@ -0,0 +1,11 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This includes functions that are meant to live entirely in .rodata
+ * (via objcopy tricks), to validate the non-executability of .rodata.
+ */
+#include "lkdtm.h"
+
+void noinstr lkdtm_rodata_do_nothing(void)
+{
+	/* Does nothing. We just want an architecture agnostic "return". */
+}
diff --git a/drivers/misc/lkdtm/stackleak.c b/drivers/misc/lkdtm/stackleak.c
new file mode 100644
index 000000000..d1a5c0705
--- /dev/null
+++ b/drivers/misc/lkdtm/stackleak.c
@@ -0,0 +1,82 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This code tests that the current task stack is properly erased (filled
+ * with STACKLEAK_POISON).
+ *
+ * Authors:
+ *   Alexander Popov <alex.popov@linux.com>
+ *   Tycho Andersen <tycho@tycho.ws>
+ */
+
+#include "lkdtm.h"
+#include <linux/stackleak.h>
+
+void lkdtm_STACKLEAK_ERASING(void)
+{
+	unsigned long *sp, left, found, i;
+	const unsigned long check_depth =
+			STACKLEAK_SEARCH_DEPTH / sizeof(unsigned long);
+	bool test_failed = false;
+
+	/*
+	 * For the details about the alignment of the poison values, see
+	 * the comment in stackleak_track_stack().
+	 */
+	sp = PTR_ALIGN(&i, sizeof(unsigned long));
+
+	left = ((unsigned long)sp & (THREAD_SIZE - 1)) / sizeof(unsigned long);
+	sp--;
+
+	/*
+	 * One 'long int' at the bottom of the thread stack is reserved
+	 * and not poisoned.
+	 */
+	if (left > 1) {
+		left--;
+	} else {
+		pr_err("FAIL: not enough stack space for the test\n");
+		test_failed = true;
+		goto end;
+	}
+
+	pr_info("checking unused part of the thread stack (%lu bytes)...\n",
+					left * sizeof(unsigned long));
+
+	/*
+	 * Search for 'check_depth' poison values in a row (just like
+	 * stackleak_erase() does).
+	 */
+	for (i = 0, found = 0; i < left && found <= check_depth; i++) {
+		if (*(sp - i) == STACKLEAK_POISON)
+			found++;
+		else
+			found = 0;
+	}
+
+	if (found <= check_depth) {
+		pr_err("FAIL: the erased part is not found (checked %lu bytes)\n",
+						i * sizeof(unsigned long));
+		test_failed = true;
+		goto end;
+	}
+
+	pr_info("the erased part begins after %lu not poisoned bytes\n",
+				(i - found) * sizeof(unsigned long));
+
+	/* The rest of thread stack should be erased */
+	for (; i < left; i++) {
+		if (*(sp - i) != STACKLEAK_POISON) {
+			pr_err("FAIL: bad value number %lu in the erased part: 0x%lx\n",
+								i, *(sp - i));
+			test_failed = true;
+		}
+	}
+
+end:
+	if (test_failed) {
+		pr_err("FAIL: the thread stack is NOT properly erased\n");
+		dump_stack();
+	} else {
+		pr_info("OK: the rest of the thread stack is properly erased\n");
+	}
+}
diff --git a/drivers/misc/lkdtm/usercopy.c b/drivers/misc/lkdtm/usercopy.c
new file mode 100644
index 000000000..cde265548
--- /dev/null
+++ b/drivers/misc/lkdtm/usercopy.c
@@ -0,0 +1,353 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This is for all the tests related to copy_to_user() and copy_from_user()
+ * hardening.
+ */
+#include "lkdtm.h"
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/sched/task_stack.h>
+#include <linux/mman.h>
+#include <linux/uaccess.h>
+#include <asm/cacheflush.h>
+
+/*
+ * Many of the tests here end up using const sizes, but those would
+ * normally be ignored by hardened usercopy, so force the compiler
+ * into choosing the non-const path to make sure we trigger the
+ * hardened usercopy checks by added "unconst" to all the const copies,
+ * and making sure "cache_size" isn't optimized into a const.
+ */
+static volatile size_t unconst;
+static volatile size_t cache_size = 1024;
+static struct kmem_cache *whitelist_cache;
+
+static const unsigned char test_text[] = "This is a test.\n";
+
+/*
+ * Instead of adding -Wno-return-local-addr, just pass the stack address
+ * through a function to obfuscate it from the compiler.
+ */
+static noinline unsigned char *trick_compiler(unsigned char *stack)
+{
+	return stack + unconst;
+}
+
+static noinline unsigned char *do_usercopy_stack_callee(int value)
+{
+	unsigned char buf[128];
+	int i;
+
+	/* Exercise stack to avoid everything living in registers. */
+	for (i = 0; i < sizeof(buf); i++) {
+		buf[i] = value & 0xff;
+	}
+
+	/*
+	 * Put the target buffer in the middle of stack allocation
+	 * so that we don't step on future stack users regardless
+	 * of stack growth direction.
+	 */
+	return trick_compiler(&buf[(128/2)-32]);
+}
+
+static noinline void do_usercopy_stack(bool to_user, bool bad_frame)
+{
+	unsigned long user_addr;
+	unsigned char good_stack[32];
+	unsigned char *bad_stack;
+	int i;
+
+	/* Exercise stack to avoid everything living in registers. */
+	for (i = 0; i < sizeof(good_stack); i++)
+		good_stack[i] = test_text[i % sizeof(test_text)];
+
+	/* This is a pointer to outside our current stack frame. */
+	if (bad_frame) {
+		bad_stack = do_usercopy_stack_callee((uintptr_t)&bad_stack);
+	} else {
+		/* Put start address just inside stack. */
+		bad_stack = task_stack_page(current) + THREAD_SIZE;
+		bad_stack -= sizeof(unsigned long);
+	}
+
+#ifdef ARCH_HAS_CURRENT_STACK_POINTER
+	pr_info("stack     : %px\n", (void *)current_stack_pointer);
+#endif
+	pr_info("good_stack: %px-%px\n", good_stack, good_stack + sizeof(good_stack));
+	pr_info("bad_stack : %px-%px\n", bad_stack, bad_stack + sizeof(good_stack));
+
+	user_addr = vm_mmap(NULL, 0, PAGE_SIZE,
+			    PROT_READ | PROT_WRITE | PROT_EXEC,
+			    MAP_ANONYMOUS | MAP_PRIVATE, 0);
+	if (user_addr >= TASK_SIZE) {
+		pr_warn("Failed to allocate user memory\n");
+		return;
+	}
+
+	if (to_user) {
+		pr_info("attempting good copy_to_user of local stack\n");
+		if (copy_to_user((void __user *)user_addr, good_stack,
+				 unconst + sizeof(good_stack))) {
+			pr_warn("copy_to_user failed unexpectedly?!\n");
+			goto free_user;
+		}
+
+		pr_info("attempting bad copy_to_user of distant stack\n");
+		if (copy_to_user((void __user *)user_addr, bad_stack,
+				 unconst + sizeof(good_stack))) {
+			pr_warn("copy_to_user failed, but lacked Oops\n");
+			goto free_user;
+		}
+	} else {
+		/*
+		 * There isn't a safe way to not be protected by usercopy
+		 * if we're going to write to another thread's stack.
+		 */
+		if (!bad_frame)
+			goto free_user;
+
+		pr_info("attempting good copy_from_user of local stack\n");
+		if (copy_from_user(good_stack, (void __user *)user_addr,
+				   unconst + sizeof(good_stack))) {
+			pr_warn("copy_from_user failed unexpectedly?!\n");
+			goto free_user;
+		}
+
+		pr_info("attempting bad copy_from_user of distant stack\n");
+		if (copy_from_user(bad_stack, (void __user *)user_addr,
+				   unconst + sizeof(good_stack))) {
+			pr_warn("copy_from_user failed, but lacked Oops\n");
+			goto free_user;
+		}
+	}
+
+free_user:
+	vm_munmap(user_addr, PAGE_SIZE);
+}
+
+/*
+ * This checks for whole-object size validation with hardened usercopy,
+ * with or without usercopy whitelisting.
+ */
+static void do_usercopy_heap_size(bool to_user)
+{
+	unsigned long user_addr;
+	unsigned char *one, *two;
+	void __user *test_user_addr;
+	void *test_kern_addr;
+	size_t size = unconst + 1024;
+
+	one = kmalloc(size, GFP_KERNEL);
+	two = kmalloc(size, GFP_KERNEL);
+	if (!one || !two) {
+		pr_warn("Failed to allocate kernel memory\n");
+		goto free_kernel;
+	}
+
+	user_addr = vm_mmap(NULL, 0, PAGE_SIZE,
+			    PROT_READ | PROT_WRITE | PROT_EXEC,
+			    MAP_ANONYMOUS | MAP_PRIVATE, 0);
+	if (user_addr >= TASK_SIZE) {
+		pr_warn("Failed to allocate user memory\n");
+		goto free_kernel;
+	}
+
+	memset(one, 'A', size);
+	memset(two, 'B', size);
+
+	test_user_addr = (void __user *)(user_addr + 16);
+	test_kern_addr = one + 16;
+
+	if (to_user) {
+		pr_info("attempting good copy_to_user of correct size\n");
+		if (copy_to_user(test_user_addr, test_kern_addr, size / 2)) {
+			pr_warn("copy_to_user failed unexpectedly?!\n");
+			goto free_user;
+		}
+
+		pr_info("attempting bad copy_to_user of too large size\n");
+		if (copy_to_user(test_user_addr, test_kern_addr, size)) {
+			pr_warn("copy_to_user failed, but lacked Oops\n");
+			goto free_user;
+		}
+	} else {
+		pr_info("attempting good copy_from_user of correct size\n");
+		if (copy_from_user(test_kern_addr, test_user_addr, size / 2)) {
+			pr_warn("copy_from_user failed unexpectedly?!\n");
+			goto free_user;
+		}
+
+		pr_info("attempting bad copy_from_user of too large size\n");
+		if (copy_from_user(test_kern_addr, test_user_addr, size)) {
+			pr_warn("copy_from_user failed, but lacked Oops\n");
+			goto free_user;
+		}
+	}
+
+free_user:
+	vm_munmap(user_addr, PAGE_SIZE);
+free_kernel:
+	kfree(one);
+	kfree(two);
+}
+
+/*
+ * This checks for the specific whitelist window within an object. If this
+ * test passes, then do_usercopy_heap_size() tests will pass too.
+ */
+static void do_usercopy_heap_whitelist(bool to_user)
+{
+	unsigned long user_alloc;
+	unsigned char *buf = NULL;
+	unsigned char __user *user_addr;
+	size_t offset, size;
+
+	/* Make sure cache was prepared. */
+	if (!whitelist_cache) {
+		pr_warn("Failed to allocate kernel cache\n");
+		return;
+	}
+
+	/*
+	 * Allocate a buffer with a whitelisted window in the buffer.
+	 */
+	buf = kmem_cache_alloc(whitelist_cache, GFP_KERNEL);
+	if (!buf) {
+		pr_warn("Failed to allocate buffer from whitelist cache\n");
+		goto free_alloc;
+	}
+
+	/* Allocate user memory we'll poke at. */
+	user_alloc = vm_mmap(NULL, 0, PAGE_SIZE,
+			    PROT_READ | PROT_WRITE | PROT_EXEC,
+			    MAP_ANONYMOUS | MAP_PRIVATE, 0);
+	if (user_alloc >= TASK_SIZE) {
+		pr_warn("Failed to allocate user memory\n");
+		goto free_alloc;
+	}
+	user_addr = (void __user *)user_alloc;
+
+	memset(buf, 'B', cache_size);
+
+	/* Whitelisted window in buffer, from kmem_cache_create_usercopy. */
+	offset = (cache_size / 4) + unconst;
+	size = (cache_size / 16) + unconst;
+
+	if (to_user) {
+		pr_info("attempting good copy_to_user inside whitelist\n");
+		if (copy_to_user(user_addr, buf + offset, size)) {
+			pr_warn("copy_to_user failed unexpectedly?!\n");
+			goto free_user;
+		}
+
+		pr_info("attempting bad copy_to_user outside whitelist\n");
+		if (copy_to_user(user_addr, buf + offset - 1, size)) {
+			pr_warn("copy_to_user failed, but lacked Oops\n");
+			goto free_user;
+		}
+	} else {
+		pr_info("attempting good copy_from_user inside whitelist\n");
+		if (copy_from_user(buf + offset, user_addr, size)) {
+			pr_warn("copy_from_user failed unexpectedly?!\n");
+			goto free_user;
+		}
+
+		pr_info("attempting bad copy_from_user outside whitelist\n");
+		if (copy_from_user(buf + offset - 1, user_addr, size)) {
+			pr_warn("copy_from_user failed, but lacked Oops\n");
+			goto free_user;
+		}
+	}
+
+free_user:
+	vm_munmap(user_alloc, PAGE_SIZE);
+free_alloc:
+	if (buf)
+		kmem_cache_free(whitelist_cache, buf);
+}
+
+/* Callable tests. */
+void lkdtm_USERCOPY_HEAP_SIZE_TO(void)
+{
+	do_usercopy_heap_size(true);
+}
+
+void lkdtm_USERCOPY_HEAP_SIZE_FROM(void)
+{
+	do_usercopy_heap_size(false);
+}
+
+void lkdtm_USERCOPY_HEAP_WHITELIST_TO(void)
+{
+	do_usercopy_heap_whitelist(true);
+}
+
+void lkdtm_USERCOPY_HEAP_WHITELIST_FROM(void)
+{
+	do_usercopy_heap_whitelist(false);
+}
+
+void lkdtm_USERCOPY_STACK_FRAME_TO(void)
+{
+	do_usercopy_stack(true, true);
+}
+
+void lkdtm_USERCOPY_STACK_FRAME_FROM(void)
+{
+	do_usercopy_stack(false, true);
+}
+
+void lkdtm_USERCOPY_STACK_BEYOND(void)
+{
+	do_usercopy_stack(true, false);
+}
+
+void lkdtm_USERCOPY_KERNEL(void)
+{
+	unsigned long user_addr;
+
+	user_addr = vm_mmap(NULL, 0, PAGE_SIZE,
+			    PROT_READ | PROT_WRITE | PROT_EXEC,
+			    MAP_ANONYMOUS | MAP_PRIVATE, 0);
+	if (user_addr >= TASK_SIZE) {
+		pr_warn("Failed to allocate user memory\n");
+		return;
+	}
+
+	pr_info("attempting good copy_to_user from kernel rodata: %px\n",
+		test_text);
+	if (copy_to_user((void __user *)user_addr, test_text,
+			 unconst + sizeof(test_text))) {
+		pr_warn("copy_to_user failed unexpectedly?!\n");
+		goto free_user;
+	}
+
+	pr_info("attempting bad copy_to_user from kernel text: %px\n",
+		vm_mmap);
+	if (copy_to_user((void __user *)user_addr, vm_mmap,
+			 unconst + PAGE_SIZE)) {
+		pr_warn("copy_to_user failed, but lacked Oops\n");
+		goto free_user;
+	}
+	pr_err("FAIL: survived bad copy_to_user()\n");
+
+free_user:
+	vm_munmap(user_addr, PAGE_SIZE);
+}
+
+void __init lkdtm_usercopy_init(void)
+{
+	/* Prepare cache that lacks SLAB_USERCOPY flag. */
+	whitelist_cache =
+		kmem_cache_create_usercopy("lkdtm-usercopy", cache_size,
+					   0, 0,
+					   cache_size / 4,
+					   cache_size / 16,
+					   NULL);
+}
+
+void __exit lkdtm_usercopy_exit(void)
+{
+	kmem_cache_destroy(whitelist_cache);
+}