Merge tag 'lkdtm-next' of...

Merge tag 'lkdtm-next' of https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux into char-misc-next

Kees writes:

lkdtm updates for next

Christophe Leroy (1):
      lkdtm/bugs: Don't expect thread termination without CONFIG_UBSAN_TRAP

Jiasheng Jiang (1):
      lkdtm/bugs: Check for the NULL pointer after calling kmalloc

Kees Cook (4):
      lkdtm/heap: Note conditions for SLAB_LINEAR_OVERFLOW
      lkdtm/usercopy: Expand size of "out of frame" object
      lkdtm: Move crashtype definitions into each category
      lkdtm: Add CFI_BACKWARD to test ROP mitigations

* tag 'lkdtm-next' of https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  lkdtm: Add CFI_BACKWARD to test ROP mitigations
  lkdtm: Move crashtype definitions into each category
  lkdtm/bugs: Don't expect thread termination without CONFIG_UBSAN_TRAP
  lkdtm/usercopy: Expand size of "out of frame" object
  lkdtm/heap: Note conditions for SLAB_LINEAR_OVERFLOW
  lkdtm/bugs: Check for the NULL pointer after calling kmalloc

drivers/misc/lkdtm/bugs.c

@@ -68,40 +68,40 @@ void __init lkdtm_bugs_init(int *recur_param)
 		recur_count = *recur_param;
 }
 
-void lkdtm_PANIC(void)
+static void lkdtm_PANIC(void)
 {
 	panic("dumptest");
 }
 
-void lkdtm_BUG(void)
+static void lkdtm_BUG(void)
 {
 	BUG();
 }
 
 static int warn_counter;
 
-void lkdtm_WARNING(void)
+static void lkdtm_WARNING(void)
 {
 	WARN_ON(++warn_counter);
 }
 
-void lkdtm_WARNING_MESSAGE(void)
+static void lkdtm_WARNING_MESSAGE(void)
 {
 	WARN(1, "Warning message trigger count: %d\n", ++warn_counter);
 }
 
-void lkdtm_EXCEPTION(void)
+static void lkdtm_EXCEPTION(void)
 {
 	*((volatile int *) 0) = 0;
 }
 
-void lkdtm_LOOP(void)
+static void lkdtm_LOOP(void)
 {
 	for (;;)
 		;
 }
 
-void lkdtm_EXHAUST_STACK(void)
+static void lkdtm_EXHAUST_STACK(void)
 {
 	pr_info("Calling function with %lu frame size to depth %d ...\n",
 		REC_STACK_SIZE, recur_count);
@@ -115,7 +115,7 @@ static noinline void __lkdtm_CORRUPT_STACK(void *stack)
 }
 
 /* This should trip the stack canary, not corrupt the return address. */
-noinline void lkdtm_CORRUPT_STACK(void)
+static noinline void lkdtm_CORRUPT_STACK(void)
 {
 	/* Use default char array length that triggers stack protection. */
 	char data[8] __aligned(sizeof(void *));
@@ -125,7 +125,7 @@ noinline void lkdtm_CORRUPT_STACK(void)
 }
 
 /* Same as above but will only get a canary with -fstack-protector-strong */
-noinline void lkdtm_CORRUPT_STACK_STRONG(void)
+static noinline void lkdtm_CORRUPT_STACK_STRONG(void)
 {
 	union {
 		unsigned short shorts[4];
@@ -139,7 +139,7 @@ noinline void lkdtm_CORRUPT_STACK_STRONG(void)
 static pid_t stack_pid;
 static unsigned long stack_addr;
 
-void lkdtm_REPORT_STACK(void)
+static void lkdtm_REPORT_STACK(void)
 {
 	volatile uintptr_t magic;
 	pid_t pid = task_pid_nr(current);
@@ -222,7 +222,7 @@ static noinline void __lkdtm_REPORT_STACK_CANARY(void *stack)
 	}
 }
 
-void lkdtm_REPORT_STACK_CANARY(void)
+static void lkdtm_REPORT_STACK_CANARY(void)
 {
 	/* Use default char array length that triggers stack protection. */
 	char data[8] __aligned(sizeof(void *)) = { };
@@ -230,7 +230,7 @@ void lkdtm_REPORT_STACK_CANARY(void)
 	__lkdtm_REPORT_STACK_CANARY((void *)&data);
 }
 
-void lkdtm_UNALIGNED_LOAD_STORE_WRITE(void)
+static void lkdtm_UNALIGNED_LOAD_STORE_WRITE(void)
 {
 	static u8 data[5] __attribute__((aligned(4))) = {1, 2, 3, 4, 5};
 	u32 *p;
@@ -245,21 +245,21 @@ void lkdtm_UNALIGNED_LOAD_STORE_WRITE(void)
 		pr_err("XFAIL: arch has CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS\n");
 }
 
-void lkdtm_SOFTLOCKUP(void)
+static void lkdtm_SOFTLOCKUP(void)
 {
 	preempt_disable();
 	for (;;)
 		cpu_relax();
 }
 
-void lkdtm_HARDLOCKUP(void)
+static void lkdtm_HARDLOCKUP(void)
 {
 	local_irq_disable();
 	for (;;)
 		cpu_relax();
 }
 
-void lkdtm_SPINLOCKUP(void)
+static void lkdtm_SPINLOCKUP(void)
 {
 	/* Must be called twice to trigger. */
 	spin_lock(&lock_me_up);
@@ -267,7 +267,7 @@ void lkdtm_SPINLOCKUP(void)
 	__release(&lock_me_up);
 }
 
-void lkdtm_HUNG_TASK(void)
+static void lkdtm_HUNG_TASK(void)
 {
 	set_current_state(TASK_UNINTERRUPTIBLE);
 	schedule();
@@ -276,7 +276,7 @@ void lkdtm_HUNG_TASK(void)
 volatile unsigned int huge = INT_MAX - 2;
 volatile unsigned int ignored;
 
-void lkdtm_OVERFLOW_SIGNED(void)
+static void lkdtm_OVERFLOW_SIGNED(void)
 {
 	int value;
 
@@ -291,7 +291,7 @@ void lkdtm_OVERFLOW_SIGNED(void)
 }
 
 
-void lkdtm_OVERFLOW_UNSIGNED(void)
+static void lkdtm_OVERFLOW_UNSIGNED(void)
 {
 	unsigned int value;
 
@@ -319,7 +319,7 @@ struct array_bounds {
 	int three;
 };
 
-void lkdtm_ARRAY_BOUNDS(void)
+static void lkdtm_ARRAY_BOUNDS(void)
 {
 	struct array_bounds_flex_array *not_checked;
 	struct array_bounds *checked;
@@ -327,6 +327,11 @@ void lkdtm_ARRAY_BOUNDS(void)
 
 	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. */
@@ -346,10 +351,13 @@ void lkdtm_ARRAY_BOUNDS(void)
 	kfree(not_checked);
 	kfree(checked);
 	pr_err("FAIL: survived array bounds overflow!\n");
-	pr_expected_config(CONFIG_UBSAN_BOUNDS);
+	if (IS_ENABLED(CONFIG_UBSAN_BOUNDS))
+		pr_expected_config(CONFIG_UBSAN_TRAP);
+	else
+		pr_expected_config(CONFIG_UBSAN_BOUNDS);
 }
 
-void lkdtm_CORRUPT_LIST_ADD(void)
+static void lkdtm_CORRUPT_LIST_ADD(void)
 {
 	/*
 	 * Initially, an empty list via LIST_HEAD:
@@ -389,7 +397,7 @@ void lkdtm_CORRUPT_LIST_ADD(void)
 	}
 }
 
-void lkdtm_CORRUPT_LIST_DEL(void)
+static void lkdtm_CORRUPT_LIST_DEL(void)
 {
 	LIST_HEAD(test_head);
 	struct lkdtm_list item;
@@ -417,7 +425,7 @@ void lkdtm_CORRUPT_LIST_DEL(void)
 }
 
 /* Test that VMAP_STACK is actually allocating with a leading guard page */
-void lkdtm_STACK_GUARD_PAGE_LEADING(void)
+static void lkdtm_STACK_GUARD_PAGE_LEADING(void)
 {
 	const unsigned char *stack = task_stack_page(current);
 	const unsigned char *ptr = stack - 1;
@@ -431,7 +439,7 @@ void lkdtm_STACK_GUARD_PAGE_LEADING(void)
 }
 
 /* Test that VMAP_STACK is actually allocating with a trailing guard page */
-void lkdtm_STACK_GUARD_PAGE_TRAILING(void)
+static void lkdtm_STACK_GUARD_PAGE_TRAILING(void)
 {
 	const unsigned char *stack = task_stack_page(current);
 	const unsigned char *ptr = stack + THREAD_SIZE;
@@ -444,7 +452,7 @@ void lkdtm_STACK_GUARD_PAGE_TRAILING(void)
 	pr_err("FAIL: accessed page after stack! (byte: %x)\n", byte);
 }
 
-void lkdtm_UNSET_SMEP(void)
+static void lkdtm_UNSET_SMEP(void)
 {
 #if IS_ENABLED(CONFIG_X86_64) && !IS_ENABLED(CONFIG_UML)
 #define MOV_CR4_DEPTH	64
@@ -510,7 +518,7 @@ void lkdtm_UNSET_SMEP(void)
 #endif
 }
 
-void lkdtm_DOUBLE_FAULT(void)
+static void lkdtm_DOUBLE_FAULT(void)
 {
 #if IS_ENABLED(CONFIG_X86_32) && !IS_ENABLED(CONFIG_UML)
 	/*
@@ -558,7 +566,7 @@ static noinline void change_pac_parameters(void)
 }
 #endif
 
-noinline void lkdtm_CORRUPT_PAC(void)
+static noinline void lkdtm_CORRUPT_PAC(void)
 {
 #ifdef CONFIG_ARM64
 #define CORRUPT_PAC_ITERATE	10
@@ -586,3 +594,37 @@ noinline void lkdtm_CORRUPT_PAC(void)
 	pr_err("XFAIL: this test is arm64-only\n");
 #endif
 }
+
+static 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(REPORT_STACK),
+	CRASHTYPE(REPORT_STACK_CANARY),
+	CRASHTYPE(UNALIGNED_LOAD_STORE_WRITE),
+	CRASHTYPE(SOFTLOCKUP),
+	CRASHTYPE(HARDLOCKUP),
+	CRASHTYPE(SPINLOCKUP),
+	CRASHTYPE(HUNG_TASK),
+	CRASHTYPE(OVERFLOW_SIGNED),
+	CRASHTYPE(OVERFLOW_UNSIGNED),
+	CRASHTYPE(ARRAY_BOUNDS),
+	CRASHTYPE(CORRUPT_LIST_ADD),
+	CRASHTYPE(CORRUPT_LIST_DEL),
+	CRASHTYPE(STACK_GUARD_PAGE_LEADING),
+	CRASHTYPE(STACK_GUARD_PAGE_TRAILING),
+	CRASHTYPE(UNSET_SMEP),
+	CRASHTYPE(DOUBLE_FAULT),
+	CRASHTYPE(CORRUPT_PAC),
+};
+
+struct crashtype_category bugs_crashtypes = {
+	.crashtypes = crashtypes,
+	.len	    = ARRAY_SIZE(crashtypes),
+};

drivers/misc/lkdtm/cfi.c

@@ -3,6 +3,7 @@
  * This is for all the tests relating directly to Control Flow Integrity.
  */
 #include "lkdtm.h"
+#include <asm/page.h>
 
 static int called_count;
 
@@ -22,7 +23,7 @@ static noinline int lkdtm_increment_int(int *counter)
 /*
  * This tries to call an indirect function with a mismatched prototype.
  */
-void lkdtm_CFI_FORWARD_PROTO(void)
+static void lkdtm_CFI_FORWARD_PROTO(void)
 {
 	/*
 	 * Matches lkdtm_increment_void()'s prototype, but not
@@ -41,3 +42,145 @@ void lkdtm_CFI_FORWARD_PROTO(void)
 	pr_err("FAIL: survived mismatched prototype function call!\n");
 	pr_expected_config(CONFIG_CFI_CLANG);
 }
+
+/*
+ * This can stay local to LKDTM, as there should not be a production reason
+ * to disable PAC && SCS.
+ */
+#ifdef CONFIG_ARM64_PTR_AUTH_KERNEL
+# ifdef CONFIG_ARM64_BTI_KERNEL
+#  define __no_pac             "branch-protection=bti"
+# else
+#  define __no_pac             "branch-protection=none"
+# endif
+# define __no_ret_protection   __noscs __attribute__((__target__(__no_pac)))
+#else
+# define __no_ret_protection   __noscs
+#endif
+
+#define no_pac_addr(addr)      \
+	((__force __typeof__(addr))((__force u64)(addr) | PAGE_OFFSET))
+
+/* The ultimate ROP gadget. */
+static noinline __no_ret_protection
+void set_return_addr_unchecked(unsigned long *expected, unsigned long *addr)
+{
+	/* Use of volatile is to make sure final write isn't seen as a dead store. */
+	unsigned long * volatile *ret_addr = (unsigned long **)__builtin_frame_address(0) + 1;
+
+	/* Make sure we've found the right place on the stack before writing it. */
+	if (no_pac_addr(*ret_addr) == expected)
+		*ret_addr = (addr);
+	else
+		/* Check architecture, stack layout, or compiler behavior... */
+		pr_warn("Eek: return address mismatch! %px != %px\n",
+			*ret_addr, addr);
+}
+
+static noinline
+void set_return_addr(unsigned long *expected, unsigned long *addr)
+{
+	/* Use of volatile is to make sure final write isn't seen as a dead store. */
+	unsigned long * volatile *ret_addr = (unsigned long **)__builtin_frame_address(0) + 1;
+
+	/* Make sure we've found the right place on the stack before writing it. */
+	if (no_pac_addr(*ret_addr) == expected)
+		*ret_addr = (addr);
+	else
+		/* Check architecture, stack layout, or compiler behavior... */
+		pr_warn("Eek: return address mismatch! %px != %px\n",
+			*ret_addr, addr);
+}
+
+static volatile int force_check;
+
+static void lkdtm_CFI_BACKWARD(void)
+{
+	/* Use calculated gotos to keep labels addressable. */
+	void *labels[] = {0, &&normal, &&redirected, &&check_normal, &&check_redirected};
+
+	pr_info("Attempting unchecked stack return address redirection ...\n");
+
+	/* Always false */
+	if (force_check) {
+		/*
+		 * Prepare to call with NULLs to avoid parameters being treated as
+		 * constants in -02.
+		 */
+		set_return_addr_unchecked(NULL, NULL);
+		set_return_addr(NULL, NULL);
+		if (force_check)
+			goto *labels[1];
+		if (force_check)
+			goto *labels[2];
+		if (force_check)
+			goto *labels[3];
+		if (force_check)
+			goto *labels[4];
+		return;
+	}
+
+	/*
+	 * Use fallthrough switch case to keep basic block ordering between
+	 * set_return_addr*() and the label after it.
+	 */
+	switch (force_check) {
+	case 0:
+		set_return_addr_unchecked(&&normal, &&redirected);
+		fallthrough;
+	case 1:
+normal:
+		/* Always true */
+		if (!force_check) {
+			pr_err("FAIL: stack return address manipulation failed!\n");
+			/* If we can't redirect "normally", we can't test mitigations. */
+			return;
+		}
+		break;
+	default:
+redirected:
+		pr_info("ok: redirected stack return address.\n");
+		break;
+	}
+
+	pr_info("Attempting checked stack return address redirection ...\n");
+
+	switch (force_check) {
+	case 0:
+		set_return_addr(&&check_normal, &&check_redirected);
+		fallthrough;
+	case 1:
+check_normal:
+		/* Always true */
+		if (!force_check) {
+			pr_info("ok: control flow unchanged.\n");
+			return;
+		}
+
+check_redirected:
+		pr_err("FAIL: stack return address was redirected!\n");
+		break;
+	}
+
+	if (IS_ENABLED(CONFIG_ARM64_PTR_AUTH_KERNEL)) {
+		pr_expected_config(CONFIG_ARM64_PTR_AUTH_KERNEL);
+		return;
+	}
+	if (IS_ENABLED(CONFIG_SHADOW_CALL_STACK)) {
+		pr_expected_config(CONFIG_SHADOW_CALL_STACK);
+		return;
+	}
+	pr_warn("This is probably expected, since this %s was built *without* %s=y nor %s=y\n",
+		lkdtm_kernel_info,
+		"CONFIG_ARM64_PTR_AUTH_KERNEL", "CONFIG_SHADOW_CALL_STACK");
+}
+
+static struct crashtype crashtypes[] = {
+	CRASHTYPE(CFI_FORWARD_PROTO),
+	CRASHTYPE(CFI_BACKWARD),
+};
+
+struct crashtype_category cfi_crashtypes = {
+	.crashtypes = crashtypes,
+	.len	    = ARRAY_SIZE(crashtypes),
+};

drivers/misc/lkdtm/core.c

@@ -86,109 +86,21 @@ static struct crashpoint crashpoints[] = {
 #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(REPORT_STACK),
-	CRASHTYPE(REPORT_STACK_CANARY),
-	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(SLAB_LINEAR_OVERFLOW),
-	CRASHTYPE(VMALLOC_LINEAR_OVERFLOW),
-	CRASHTYPE(WRITE_AFTER_FREE),
-	CRASHTYPE(READ_AFTER_FREE),
-	CRASHTYPE(WRITE_BUDDY_AFTER_FREE),
-	CRASHTYPE(READ_BUDDY_AFTER_FREE),
-	CRASHTYPE(SLAB_INIT_ON_ALLOC),
-	CRASHTYPE(BUDDY_INIT_ON_ALLOC),
-	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(WRITE_OPD),
-	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(FORTIFIED_OBJECT),
-	CRASHTYPE(FORTIFIED_SUBOBJECT),
-	CRASHTYPE(FORTIFIED_STRSCPY),
-	CRASHTYPE(DOUBLE_FAULT),
+/* List of possible types for crashes that can be triggered. */
+static const struct crashtype_category *crashtype_categories[] = {
+	&bugs_crashtypes,
+	&heap_crashtypes,
+	&perms_crashtypes,
+	&refcount_crashtypes,
+	&usercopy_crashtypes,
+	&stackleak_crashtypes,
+	&cfi_crashtypes,
+	&fortify_crashtypes,
 #ifdef CONFIG_PPC_64S_HASH_MMU
-	CRASHTYPE(PPC_SLB_MULTIHIT),
+	&powerpc_crashtypes,
 #endif
 };
 
-
 /* Global kprobe entry and crashtype. */
 static struct kprobe *lkdtm_kprobe;
 static struct crashpoint *lkdtm_crashpoint;
@@ -223,11 +135,16 @@ char *lkdtm_kernel_info;
 /* Return the crashtype number or NULL if the name is invalid */
 static const struct crashtype *find_crashtype(const char *name)
 {
-	int i;
+	int cat, idx;
+
+	for (cat = 0; cat < ARRAY_SIZE(crashtype_categories); cat++) {
+		for (idx = 0; idx < crashtype_categories[cat]->len; idx++) {
+			struct crashtype *crashtype;
 
-	for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
-		if (!strcmp(name, crashtypes[i].name))
-			return &crashtypes[i];
+			crashtype = &crashtype_categories[cat]->crashtypes[idx];
+			if (!strcmp(name, crashtype->name))
+				return crashtype;
+		}
 	}
 
 	return NULL;
@@ -347,17 +264,24 @@ static ssize_t lkdtm_debugfs_entry(struct file *f,
 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
 		size_t count, loff_t *off)
 {
+	int n, cat, idx;
+	ssize_t out;
 	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);
+
+	for (cat = 0; cat < ARRAY_SIZE(crashtype_categories); cat++) {
+		for (idx = 0; idx < crashtype_categories[cat]->len; idx++) {
+			struct crashtype *crashtype;
+
+			crashtype = &crashtype_categories[cat]->crashtypes[idx];
+			n += scnprintf(buf + n, PAGE_SIZE - n, "%s\n",
+				      crashtype->name);
+		}
 	}
 	buf[n] = '\0';
 

drivers/misc/lkdtm/fortify.c

@@ -10,7 +10,7 @@
 
 static volatile int fortify_scratch_space;
 
-void lkdtm_FORTIFIED_OBJECT(void)
+static void lkdtm_FORTIFIED_OBJECT(void)
 {
 	struct target {
 		char a[10];
@@ -31,7 +31,7 @@ void lkdtm_FORTIFIED_OBJECT(void)
 	pr_expected_config(CONFIG_FORTIFY_SOURCE);
 }
 
-void lkdtm_FORTIFIED_SUBOBJECT(void)
+static void lkdtm_FORTIFIED_SUBOBJECT(void)
 {
 	struct target {
 		char a[10];
@@ -67,7 +67,7 @@ void lkdtm_FORTIFIED_SUBOBJECT(void)
  * strscpy and generate a panic because there is a write overflow (i.e. src
  * length is greater than dst length).
  */
-void lkdtm_FORTIFIED_STRSCPY(void)
+static void lkdtm_FORTIFIED_STRSCPY(void)
 {
 	char *src;
 	char dst[5];
@@ -134,3 +134,14 @@ void lkdtm_FORTIFIED_STRSCPY(void)
 
 	kfree(src);
 }
+
+static struct crashtype crashtypes[] = {
+	CRASHTYPE(FORTIFIED_OBJECT),
+	CRASHTYPE(FORTIFIED_SUBOBJECT),
+	CRASHTYPE(FORTIFIED_STRSCPY),
+};
+
+struct crashtype_category fortify_crashtypes = {
+	.crashtypes = crashtypes,
+	.len	    = ARRAY_SIZE(crashtypes),
+};

drivers/misc/lkdtm/heap.c

@@ -22,8 +22,11 @@ static volatile int __offset = 1;
 /*
  * If there aren't guard pages, it's likely that a consecutive allocation will
  * let us overflow into the second allocation without overwriting something real.
+ *
+ * This should always be caught because there is an unconditional unmapped
+ * page after vmap allocations.
  */
-void lkdtm_VMALLOC_LINEAR_OVERFLOW(void)
+static void lkdtm_VMALLOC_LINEAR_OVERFLOW(void)
 {
 	char *one, *two;
 
@@ -41,8 +44,11 @@ void lkdtm_VMALLOC_LINEAR_OVERFLOW(void)
  * 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.
+ *
+ * This should get caught by either memory tagging, KASan, or by using
+ * CONFIG_SLUB_DEBUG=y and slub_debug=ZF (or CONFIG_SLUB_DEBUG_ON=y).
  */
-void lkdtm_SLAB_LINEAR_OVERFLOW(void)
+static void lkdtm_SLAB_LINEAR_OVERFLOW(void)
 {
 	size_t len = 1020;
 	u32 *data = kmalloc(len, GFP_KERNEL);
@@ -54,7 +60,7 @@ void lkdtm_SLAB_LINEAR_OVERFLOW(void)
 	kfree(data);
 }
 
-void lkdtm_WRITE_AFTER_FREE(void)
+static void lkdtm_WRITE_AFTER_FREE(void)
 {
 	int *base, *again;
 	size_t len = 1024;
@@ -80,7 +86,7 @@ void lkdtm_WRITE_AFTER_FREE(void)
 		pr_info("Hmm, didn't get the same memory range.\n");
 }
 
-void lkdtm_READ_AFTER_FREE(void)
+static void lkdtm_READ_AFTER_FREE(void)
 {
 	int *base, *val, saw;
 	size_t len = 1024;
@@ -124,7 +130,7 @@ void lkdtm_READ_AFTER_FREE(void)
 	kfree(val);
 }
 
-void lkdtm_WRITE_BUDDY_AFTER_FREE(void)
+static void lkdtm_WRITE_BUDDY_AFTER_FREE(void)
 {
 	unsigned long p = __get_free_page(GFP_KERNEL);
 	if (!p) {
@@ -144,7 +150,7 @@ void lkdtm_WRITE_BUDDY_AFTER_FREE(void)
 	schedule();
 }
 
-void lkdtm_READ_BUDDY_AFTER_FREE(void)
+static void lkdtm_READ_BUDDY_AFTER_FREE(void)
 {
 	unsigned long p = __get_free_page(GFP_KERNEL);
 	int saw, *val;
@@ -181,7 +187,7 @@ void lkdtm_READ_BUDDY_AFTER_FREE(void)
 	kfree(val);
 }
 
-void lkdtm_SLAB_INIT_ON_ALLOC(void)
+static void lkdtm_SLAB_INIT_ON_ALLOC(void)
 {
 	u8 *first;
 	u8 *val;
@@ -213,7 +219,7 @@ void lkdtm_SLAB_INIT_ON_ALLOC(void)
 	kfree(val);
 }
 
-void lkdtm_BUDDY_INIT_ON_ALLOC(void)
+static void lkdtm_BUDDY_INIT_ON_ALLOC(void)
 {
 	u8 *first;
 	u8 *val;
@@ -246,7 +252,7 @@ void lkdtm_BUDDY_INIT_ON_ALLOC(void)
 	free_page((unsigned long)val);
 }
 
-void lkdtm_SLAB_FREE_DOUBLE(void)
+static void lkdtm_SLAB_FREE_DOUBLE(void)
 {
 	int *val;
 
@@ -263,7 +269,7 @@ void lkdtm_SLAB_FREE_DOUBLE(void)
 	kmem_cache_free(double_free_cache, val);
 }
 
-void lkdtm_SLAB_FREE_CROSS(void)
+static void lkdtm_SLAB_FREE_CROSS(void)
 {
 	int *val;
 
@@ -279,7 +285,7 @@ void lkdtm_SLAB_FREE_CROSS(void)
 	kmem_cache_free(b_cache, val);
 }
 
-void lkdtm_SLAB_FREE_PAGE(void)
+static void lkdtm_SLAB_FREE_PAGE(void)
 {
 	unsigned long p = __get_free_page(GFP_KERNEL);
 
@@ -313,3 +319,22 @@ void __exit lkdtm_heap_exit(void)
 	kmem_cache_destroy(a_cache);
 	kmem_cache_destroy(b_cache);
 }
+
+static struct crashtype crashtypes[] = {
+	CRASHTYPE(SLAB_LINEAR_OVERFLOW),
+	CRASHTYPE(VMALLOC_LINEAR_OVERFLOW),
+	CRASHTYPE(WRITE_AFTER_FREE),
+	CRASHTYPE(READ_AFTER_FREE),
+	CRASHTYPE(WRITE_BUDDY_AFTER_FREE),
+	CRASHTYPE(READ_BUDDY_AFTER_FREE),
+	CRASHTYPE(SLAB_INIT_ON_ALLOC),
+	CRASHTYPE(BUDDY_INIT_ON_ALLOC),
+	CRASHTYPE(SLAB_FREE_DOUBLE),
+	CRASHTYPE(SLAB_FREE_CROSS),
+	CRASHTYPE(SLAB_FREE_PAGE),
+};
+
+struct crashtype_category heap_crashtypes = {
+	.crashtypes = crashtypes,
+	.len	    = ARRAY_SIZE(crashtypes),
+};

drivers/misc/lkdtm/lkdtm.h

@@ -9,19 +9,19 @@
 extern char *lkdtm_kernel_info;
 
 #define pr_expected_config(kconfig)				\
-{								\
+do {								\
 	if (IS_ENABLED(kconfig)) 				\
 		pr_err("Unexpected! This %s was built with " #kconfig "=y\n", \
 			lkdtm_kernel_info);			\
 	else							\
 		pr_warn("This is probably expected, since this %s was built *without* " #kconfig "=y\n", \
 			lkdtm_kernel_info);			\
-}
+} while (0)
 
 #ifndef MODULE
 int lkdtm_check_bool_cmdline(const char *param);
 #define pr_expected_config_param(kconfig, param)		\
-{								\
+do {								\
 	if (IS_ENABLED(kconfig)) {				\
 		switch (lkdtm_check_bool_cmdline(param)) {	\
 		case 0:						\
@@ -52,119 +52,49 @@ int lkdtm_check_bool_cmdline(const char *param);
 			break;					\
 		}						\
 	}							\
-}
+} while (0)
 #else
 #define pr_expected_config_param(kconfig, param) pr_expected_config(kconfig)
 #endif
 
-/* bugs.c */
+/* Crash types. */
+struct crashtype {
+	const char *name;
+	void (*func)(void);
+};
+
+#define CRASHTYPE(_name)			\
+	{					\
+		.name = __stringify(_name),	\
+		.func = lkdtm_ ## _name,	\
+	}
+
+/* Category's collection of crashtypes. */
+struct crashtype_category {
+	struct crashtype *crashtypes;
+	size_t len;
+};
+
+/* Each category's crashtypes list. */
+extern struct crashtype_category bugs_crashtypes;
+extern struct crashtype_category heap_crashtypes;
+extern struct crashtype_category perms_crashtypes;
+extern struct crashtype_category refcount_crashtypes;
+extern struct crashtype_category usercopy_crashtypes;
+extern struct crashtype_category stackleak_crashtypes;
+extern struct crashtype_category cfi_crashtypes;
+extern struct crashtype_category fortify_crashtypes;
+extern struct crashtype_category powerpc_crashtypes;
+
+/* Each category's init/exit routines. */
 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_REPORT_STACK(void);
-void lkdtm_REPORT_STACK_CANARY(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);
-
-/* heap.c */
 void __init lkdtm_heap_init(void);
 void __exit lkdtm_heap_exit(void);
-void lkdtm_VMALLOC_LINEAR_OVERFLOW(void);
-void lkdtm_SLAB_LINEAR_OVERFLOW(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_INIT_ON_ALLOC(void);
-void lkdtm_BUDDY_INIT_ON_ALLOC(void);
-void lkdtm_SLAB_FREE_DOUBLE(void);
-void lkdtm_SLAB_FREE_CROSS(void);
-void lkdtm_SLAB_FREE_PAGE(void);
-
-/* 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_WRITE_OPD(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);
-
-/* 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);
-
-/* rodata.c */
-void lkdtm_rodata_do_nothing(void);
-
-/* 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);
-
-/* stackleak.c */
-void lkdtm_STACKLEAK_ERASING(void);
-
-/* cfi.c */
-void lkdtm_CFI_FORWARD_PROTO(void);
 
-/* fortify.c */
-void lkdtm_FORTIFIED_OBJECT(void);
-void lkdtm_FORTIFIED_SUBOBJECT(void);
-void lkdtm_FORTIFIED_STRSCPY(void);
-
-/* powerpc.c */
-void lkdtm_PPC_SLB_MULTIHIT(void);
+/* Special declaration for function-in-rodata. */
+void lkdtm_rodata_do_nothing(void);
 
 #endif

drivers/misc/lkdtm/perms.c

@@ -103,7 +103,7 @@ static void execute_user_location(void *dst)
 	pr_err("FAIL: func returned\n");
 }
 
-void lkdtm_WRITE_RO(void)
+static void lkdtm_WRITE_RO(void)
 {
 	/* Explicitly cast away "const" for the test and make volatile. */
 	volatile unsigned long *ptr = (unsigned long *)&rodata;
@@ -113,7 +113,7 @@ void lkdtm_WRITE_RO(void)
 	pr_err("FAIL: survived bad write\n");
 }
 
-void lkdtm_WRITE_RO_AFTER_INIT(void)
+static void lkdtm_WRITE_RO_AFTER_INIT(void)
 {
 	volatile unsigned long *ptr = &ro_after_init;
 
@@ -132,7 +132,7 @@ void lkdtm_WRITE_RO_AFTER_INIT(void)
 	pr_err("FAIL: survived bad write\n");
 }
 
-void lkdtm_WRITE_KERN(void)
+static void lkdtm_WRITE_KERN(void)
 {
 	size_t size;
 	volatile unsigned char *ptr;
@@ -149,7 +149,7 @@ void lkdtm_WRITE_KERN(void)
 	do_overwritten();
 }
 
-void lkdtm_WRITE_OPD(void)
+static void lkdtm_WRITE_OPD(void)
 {
 	size_t size = sizeof(func_desc_t);
 	void (*func)(void) = do_nothing;
@@ -166,38 +166,38 @@ void lkdtm_WRITE_OPD(void)
 	func();
 }
 
-void lkdtm_EXEC_DATA(void)
+static void lkdtm_EXEC_DATA(void)
 {
 	execute_location(data_area, CODE_WRITE);
 }
 
-void lkdtm_EXEC_STACK(void)
+static void lkdtm_EXEC_STACK(void)
 {
 	u8 stack_area[EXEC_SIZE];
 	execute_location(stack_area, CODE_WRITE);
 }
 
-void lkdtm_EXEC_KMALLOC(void)
+static 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)
+static 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)
+static void lkdtm_EXEC_RODATA(void)
 {
 	execute_location(dereference_function_descriptor(lkdtm_rodata_do_nothing),
 			 CODE_AS_IS);
 }
 
-void lkdtm_EXEC_USERSPACE(void)
+static void lkdtm_EXEC_USERSPACE(void)
 {
 	unsigned long user_addr;
 
@@ -212,12 +212,12 @@ void lkdtm_EXEC_USERSPACE(void)
 	vm_munmap(user_addr, PAGE_SIZE);
 }
 
-void lkdtm_EXEC_NULL(void)
+static void lkdtm_EXEC_NULL(void)
 {
 	execute_location(NULL, CODE_AS_IS);
 }
 
-void lkdtm_ACCESS_USERSPACE(void)
+static void lkdtm_ACCESS_USERSPACE(void)
 {
 	unsigned long user_addr, tmp = 0;
 	unsigned long *ptr;
@@ -250,7 +250,7 @@ void lkdtm_ACCESS_USERSPACE(void)
 	vm_munmap(user_addr, PAGE_SIZE);
 }
 
-void lkdtm_ACCESS_NULL(void)
+static void lkdtm_ACCESS_NULL(void)
 {
 	unsigned long tmp;
 	volatile unsigned long *ptr = (unsigned long *)NULL;
@@ -270,3 +270,24 @@ void __init lkdtm_perms_init(void)
 	/* Make sure we can write to __ro_after_init values during __init */
 	ro_after_init |= 0xAA;
 }
+
+static struct crashtype crashtypes[] = {
+	CRASHTYPE(WRITE_RO),
+	CRASHTYPE(WRITE_RO_AFTER_INIT),
+	CRASHTYPE(WRITE_KERN),
+	CRASHTYPE(WRITE_OPD),
+	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),
+};
+
+struct crashtype_category perms_crashtypes = {
+	.crashtypes = crashtypes,
+	.len	    = ARRAY_SIZE(crashtypes),
+};

drivers/misc/lkdtm/powerpc.c

@@ -100,7 +100,7 @@ static void insert_dup_slb_entry_0(void)
 	preempt_enable();
 }
 
-void lkdtm_PPC_SLB_MULTIHIT(void)
+static void lkdtm_PPC_SLB_MULTIHIT(void)
 {
 	if (!radix_enabled()) {
 		pr_info("Injecting SLB multihit errors\n");
@@ -118,3 +118,12 @@ void lkdtm_PPC_SLB_MULTIHIT(void)
 		pr_err("XFAIL: This test is for ppc64 and with hash mode MMU only\n");
 	}
 }
+
+static struct crashtype crashtypes[] = {
+	CRASHTYPE(PPC_SLB_MULTIHIT),
+};
+
+struct crashtype_category powerpc_crashtypes = {
+	.crashtypes = crashtypes,
+	.len	    = ARRAY_SIZE(crashtypes),
+};

drivers/misc/lkdtm/refcount.c

@@ -24,7 +24,7 @@ static void overflow_check(refcount_t *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)
+static void lkdtm_REFCOUNT_INC_OVERFLOW(void)
 {
 	refcount_t over = REFCOUNT_INIT(REFCOUNT_MAX - 1);
 
@@ -40,7 +40,7 @@ void lkdtm_REFCOUNT_INC_OVERFLOW(void)
 }
 
 /* refcount_add() should behave just like refcount_inc() above. */
-void lkdtm_REFCOUNT_ADD_OVERFLOW(void)
+static void lkdtm_REFCOUNT_ADD_OVERFLOW(void)
 {
 	refcount_t over = REFCOUNT_INIT(REFCOUNT_MAX - 1);
 
@@ -58,7 +58,7 @@ void lkdtm_REFCOUNT_ADD_OVERFLOW(void)
 }
 
 /* refcount_inc_not_zero() should behave just like refcount_inc() above. */
-void lkdtm_REFCOUNT_INC_NOT_ZERO_OVERFLOW(void)
+static void lkdtm_REFCOUNT_INC_NOT_ZERO_OVERFLOW(void)
 {
 	refcount_t over = REFCOUNT_INIT(REFCOUNT_MAX);
 
@@ -70,7 +70,7 @@ void lkdtm_REFCOUNT_INC_NOT_ZERO_OVERFLOW(void)
 }
 
 /* refcount_add_not_zero() should behave just like refcount_inc() above. */
-void lkdtm_REFCOUNT_ADD_NOT_ZERO_OVERFLOW(void)
+static void lkdtm_REFCOUNT_ADD_NOT_ZERO_OVERFLOW(void)
 {
 	refcount_t over = REFCOUNT_INIT(REFCOUNT_MAX);
 
@@ -103,7 +103,7 @@ static void check_zero(refcount_t *ref)
  * 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)
+static void lkdtm_REFCOUNT_DEC_ZERO(void)
 {
 	refcount_t zero = REFCOUNT_INIT(2);
 
@@ -142,7 +142,7 @@ static void check_negative(refcount_t *ref, int start)
 }
 
 /* A refcount_dec() going negative should saturate and may WARN. */
-void lkdtm_REFCOUNT_DEC_NEGATIVE(void)
+static void lkdtm_REFCOUNT_DEC_NEGATIVE(void)
 {
 	refcount_t neg = REFCOUNT_INIT(0);
 
@@ -156,7 +156,7 @@ void lkdtm_REFCOUNT_DEC_NEGATIVE(void)
  * A refcount_dec_and_test() should act like refcount_dec() above when
  * going negative.
  */
-void lkdtm_REFCOUNT_DEC_AND_TEST_NEGATIVE(void)
+static void lkdtm_REFCOUNT_DEC_AND_TEST_NEGATIVE(void)
 {
 	refcount_t neg = REFCOUNT_INIT(0);
 
@@ -171,7 +171,7 @@ void lkdtm_REFCOUNT_DEC_AND_TEST_NEGATIVE(void)
  * A refcount_sub_and_test() should act like refcount_dec_and_test()
  * above when going negative.
  */
-void lkdtm_REFCOUNT_SUB_AND_TEST_NEGATIVE(void)
+static void lkdtm_REFCOUNT_SUB_AND_TEST_NEGATIVE(void)
 {
 	refcount_t neg = REFCOUNT_INIT(3);
 
@@ -203,7 +203,7 @@ static void check_from_zero(refcount_t *ref)
 /*
  * A refcount_inc() from zero should pin to zero or saturate and may WARN.
  */
-void lkdtm_REFCOUNT_INC_ZERO(void)
+static void lkdtm_REFCOUNT_INC_ZERO(void)
 {
 	refcount_t zero = REFCOUNT_INIT(0);
 
@@ -228,7 +228,7 @@ void lkdtm_REFCOUNT_INC_ZERO(void)
  * A refcount_add() should act like refcount_inc() above when starting
  * at zero.
  */
-void lkdtm_REFCOUNT_ADD_ZERO(void)
+static void lkdtm_REFCOUNT_ADD_ZERO(void)
 {
 	refcount_t zero = REFCOUNT_INIT(0);
 
@@ -267,7 +267,7 @@ static void check_saturated(refcount_t *ref)
  * A refcount_inc() from a saturated value should at most warn about
  * being saturated already.
  */
-void lkdtm_REFCOUNT_INC_SATURATED(void)
+static void lkdtm_REFCOUNT_INC_SATURATED(void)
 {
 	refcount_t sat = REFCOUNT_INIT(REFCOUNT_SATURATED);
 
@@ -278,7 +278,7 @@ void lkdtm_REFCOUNT_INC_SATURATED(void)
 }
 
 /* Should act like refcount_inc() above from saturated. */
-void lkdtm_REFCOUNT_DEC_SATURATED(void)
+static void lkdtm_REFCOUNT_DEC_SATURATED(void)
 {
 	refcount_t sat = REFCOUNT_INIT(REFCOUNT_SATURATED);
 
@@ -289,7 +289,7 @@ void lkdtm_REFCOUNT_DEC_SATURATED(void)
 }
 
 /* Should act like refcount_inc() above from saturated. */
-void lkdtm_REFCOUNT_ADD_SATURATED(void)
+static void lkdtm_REFCOUNT_ADD_SATURATED(void)
 {
 	refcount_t sat = REFCOUNT_INIT(REFCOUNT_SATURATED);
 
@@ -300,7 +300,7 @@ void lkdtm_REFCOUNT_ADD_SATURATED(void)
 }
 
 /* Should act like refcount_inc() above from saturated. */
-void lkdtm_REFCOUNT_INC_NOT_ZERO_SATURATED(void)
+static void lkdtm_REFCOUNT_INC_NOT_ZERO_SATURATED(void)
 {
 	refcount_t sat = REFCOUNT_INIT(REFCOUNT_SATURATED);
 
@@ -312,7 +312,7 @@ void lkdtm_REFCOUNT_INC_NOT_ZERO_SATURATED(void)
 }
 
 /* Should act like refcount_inc() above from saturated. */
-void lkdtm_REFCOUNT_ADD_NOT_ZERO_SATURATED(void)
+static void lkdtm_REFCOUNT_ADD_NOT_ZERO_SATURATED(void)
 {
 	refcount_t sat = REFCOUNT_INIT(REFCOUNT_SATURATED);
 
@@ -324,7 +324,7 @@ void lkdtm_REFCOUNT_ADD_NOT_ZERO_SATURATED(void)
 }
 
 /* Should act like refcount_inc() above from saturated. */
-void lkdtm_REFCOUNT_DEC_AND_TEST_SATURATED(void)
+static void lkdtm_REFCOUNT_DEC_AND_TEST_SATURATED(void)
 {
 	refcount_t sat = REFCOUNT_INIT(REFCOUNT_SATURATED);
 
@@ -336,7 +336,7 @@ void lkdtm_REFCOUNT_DEC_AND_TEST_SATURATED(void)
 }
 
 /* Should act like refcount_inc() above from saturated. */
-void lkdtm_REFCOUNT_SUB_AND_TEST_SATURATED(void)
+static void lkdtm_REFCOUNT_SUB_AND_TEST_SATURATED(void)
 {
 	refcount_t sat = REFCOUNT_INIT(REFCOUNT_SATURATED);
 
@@ -348,7 +348,7 @@ void lkdtm_REFCOUNT_SUB_AND_TEST_SATURATED(void)
 }
 
 /* Used to time the existing atomic_t when used for reference counting */
-void lkdtm_ATOMIC_TIMING(void)
+static void lkdtm_ATOMIC_TIMING(void)
 {
 	unsigned int i;
 	atomic_t count = ATOMIC_INIT(1);
@@ -373,7 +373,7 @@ void lkdtm_ATOMIC_TIMING(void)
  *    cd /sys/kernel/debug/provoke-crash
  *    perf stat -B -- cat <(echo REFCOUNT_TIMING) > DIRECT
  */
-void lkdtm_REFCOUNT_TIMING(void)
+static void lkdtm_REFCOUNT_TIMING(void)
 {
 	unsigned int i;
 	refcount_t count = REFCOUNT_INIT(1);
@@ -390,3 +390,30 @@ void lkdtm_REFCOUNT_TIMING(void)
 	else
 		pr_info("refcount timing: done\n");
 }
+
+static struct crashtype crashtypes[] = {
+	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(ATOMIC_TIMING),
+	CRASHTYPE(REFCOUNT_TIMING),
+};
+
+struct crashtype_category refcount_crashtypes = {
+	.crashtypes = crashtypes,
+	.len	    = ARRAY_SIZE(crashtypes),
+};

drivers/misc/lkdtm/stackleak.c

@@ -11,7 +11,7 @@
 #include "lkdtm.h"
 #include <linux/stackleak.h>
 
-void lkdtm_STACKLEAK_ERASING(void)
+static void lkdtm_STACKLEAK_ERASING(void)
 {
 	unsigned long *sp, left, found, i;
 	const unsigned long check_depth =
@@ -80,3 +80,12 @@ void lkdtm_STACKLEAK_ERASING(void)
 		pr_info("OK: the rest of the thread stack is properly erased\n");
 	}
 }
+
+static struct crashtype crashtypes[] = {
+	CRASHTYPE(STACKLEAK_ERASING),
+};
+
+struct crashtype_category stackleak_crashtypes = {
+	.crashtypes = crashtypes,
+	.len	    = ARRAY_SIZE(crashtypes),
+};

drivers/misc/lkdtm/usercopy.c

@@ -30,12 +30,12 @@ static const unsigned char test_text[] = "This is a test.\n";
  */
 static noinline unsigned char *trick_compiler(unsigned char *stack)
 {
-	return stack + 0;
+	return stack + unconst;
 }
 
 static noinline unsigned char *do_usercopy_stack_callee(int value)
 {
-	unsigned char buf[32];
+	unsigned char buf[128];
 	int i;
 
 	/* Exercise stack to avoid everything living in registers. */
@@ -43,7 +43,12 @@ static noinline unsigned char *do_usercopy_stack_callee(int value)
 		buf[i] = value & 0xff;
 	}
 
-	return trick_compiler(buf);
+	/*
+	 * 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)
@@ -66,6 +71,12 @@ static noinline void do_usercopy_stack(bool to_user, bool bad_frame)
 		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);
@@ -261,42 +272,42 @@ static void do_usercopy_heap_whitelist(bool to_user)
 }
 
 /* Callable tests. */
-void lkdtm_USERCOPY_HEAP_SIZE_TO(void)
+static void lkdtm_USERCOPY_HEAP_SIZE_TO(void)
 {
 	do_usercopy_heap_size(true);
 }
 
-void lkdtm_USERCOPY_HEAP_SIZE_FROM(void)
+static void lkdtm_USERCOPY_HEAP_SIZE_FROM(void)
 {
 	do_usercopy_heap_size(false);
 }
 
-void lkdtm_USERCOPY_HEAP_WHITELIST_TO(void)
+static void lkdtm_USERCOPY_HEAP_WHITELIST_TO(void)
 {
 	do_usercopy_heap_whitelist(true);
 }
 
-void lkdtm_USERCOPY_HEAP_WHITELIST_FROM(void)
+static void lkdtm_USERCOPY_HEAP_WHITELIST_FROM(void)
 {
 	do_usercopy_heap_whitelist(false);
 }
 
-void lkdtm_USERCOPY_STACK_FRAME_TO(void)
+static void lkdtm_USERCOPY_STACK_FRAME_TO(void)
 {
 	do_usercopy_stack(true, true);
 }
 
-void lkdtm_USERCOPY_STACK_FRAME_FROM(void)
+static void lkdtm_USERCOPY_STACK_FRAME_FROM(void)
 {
 	do_usercopy_stack(false, true);
 }
 
-void lkdtm_USERCOPY_STACK_BEYOND(void)
+static void lkdtm_USERCOPY_STACK_BEYOND(void)
 {
 	do_usercopy_stack(true, false);
 }
 
-void lkdtm_USERCOPY_KERNEL(void)
+static void lkdtm_USERCOPY_KERNEL(void)
 {
 	unsigned long user_addr;
 
@@ -345,3 +356,19 @@ void __exit lkdtm_usercopy_exit(void)
 {
 	kmem_cache_destroy(whitelist_cache);
 }
+
+static struct crashtype crashtypes[] = {
+	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),
+};
+
+struct crashtype_category usercopy_crashtypes = {
+	.crashtypes = crashtypes,
+	.len	    = ARRAY_SIZE(crashtypes),
+};

tools/testing/selftests/lkdtm/config

@@ -9,3 +9,5 @@ CONFIG_UBSAN=y
 CONFIG_UBSAN_BOUNDS=y
 CONFIG_UBSAN_TRAP=y
 CONFIG_STACKPROTECTOR_STRONG=y
+CONFIG_SLUB_DEBUG=y
+CONFIG_SLUB_DEBUG_ON=y

tools/testing/selftests/lkdtm/tests.txt

@@ -74,6 +74,7 @@ USERCOPY_STACK_BEYOND
 USERCOPY_KERNEL
 STACKLEAK_ERASING OK: the rest of the thread stack is properly erased
 CFI_FORWARD_PROTO
+CFI_BACKWARD call trace:|ok: control flow unchanged
 FORTIFIED_STRSCPY
 FORTIFIED_OBJECT
 FORTIFIED_SUBOBJECT