1 files changed, 262 insertions, 89 deletions

diff --git a/drivers/misc/lkdtm/bugs.c b/drivers/misc/lkdtm/bugs.c
index 88c218a9f8b3..376047beea3d 100644
--- a/drivers/misc/lkdtm/bugs.c
+++ b/drivers/misc/lkdtm/bugs.c
@@ -6,12 +6,14 @@
  * test source files.
  */
 #include "lkdtm.h"
+#include <linux/cpu.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>
+#include <linux/stop_machine.h>
+#include <linux/uaccess.h>
 
 #if IS_ENABLED(CONFIG_X86_32) && !IS_ENABLED(CONFIG_UML)
 #include <asm/desc.h>
@@ -29,7 +31,7 @@ struct lkdtm_list {
 #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)
+#define REC_STACK_SIZE (THREAD_SIZE / 8UL)
 #endif
 #define REC_NUM_DEFAULT ((THREAD_SIZE / REC_STACK_SIZE) * 2)
 
@@ -41,20 +43,22 @@ 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())
- * */
+ * - stack variables are written (memset()) and read (buf[..] passed as arg)
+ * - function may have external effects (memzero_explicit())
+ * - no tail recursion possible
+ */
 static int noinline recursive_loop(int remaining)
 {
 	volatile char buf[REC_STACK_SIZE];
+	volatile int ret;
 
 	memset((void *)buf, remaining & 0xFF, sizeof(buf));
-	pr_info("loop %d/%d ...\n", (int)buf[remaining % sizeof(buf)],
-		recur_count);
 	if (!remaining)
-		return 0;
+		ret = 0;
 	else
-		return recursive_loop(remaining - 1);
+		ret = recursive_loop((int)buf[remaining % sizeof(buf)] - 1);
+	memzero_explicit((void *)buf, sizeof(buf));
+	return ret;
 }
 
 /* If the depth is negative, use the default, otherwise keep parameter. */
@@ -66,40 +70,65 @@ 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 int panic_stop_irqoff_fn(void *arg)
+{
+	atomic_t *v = arg;
+
+	/*
+	 * As stop_machine() disables interrupts, all CPUs within this function
+	 * have interrupts disabled and cannot take a regular IPI.
+	 *
+	 * The last CPU which enters here will trigger a panic, and as all CPUs
+	 * cannot take a regular IPI, we'll only be able to stop secondaries if
+	 * smp_send_stop() or crash_smp_send_stop() uses an NMI.
+	 */
+	if (atomic_inc_return(v) == num_online_cpus())
+		panic("panic stop irqoff test");
+
+	for (;;)
+		cpu_relax();
+}
+
+static void lkdtm_PANIC_STOP_IRQOFF(void)
+{
+	atomic_t v = ATOMIC_INIT(0);
+	stop_machine(panic_stop_irqoff_fn, &v, cpu_online_mask);
+}
+
+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);
@@ -113,7 +142,7 @@ 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 *));
@@ -123,7 +152,7 @@ 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];
@@ -137,7 +166,7 @@ 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);
@@ -151,7 +180,84 @@ void lkdtm_REPORT_STACK(void)
 	pr_info("Stack offset: %d\n", (int)(stack_addr - (uintptr_t)&magic));
 }
 
-void lkdtm_UNALIGNED_LOAD_STORE_WRITE(void)
+static pid_t stack_canary_pid;
+static unsigned long stack_canary;
+static unsigned long stack_canary_offset;
+
+static noinline void __lkdtm_REPORT_STACK_CANARY(void *stack)
+{
+	int i = 0;
+	pid_t pid = task_pid_nr(current);
+	unsigned long *canary = (unsigned long *)stack;
+	unsigned long current_offset = 0, init_offset = 0;
+
+	/* Do our best to find the canary in a 16 word window ... */
+	for (i = 1; i < 16; i++) {
+		canary = (unsigned long *)stack + i;
+#ifdef CONFIG_STACKPROTECTOR
+		if (*canary == current->stack_canary)
+			current_offset = i;
+		if (*canary == init_task.stack_canary)
+			init_offset = i;
+#endif
+	}
+
+	if (current_offset == 0) {
+		/*
+		 * If the canary doesn't match what's in the task_struct,
+		 * we're either using a global canary or the stack frame
+		 * layout changed.
+		 */
+		if (init_offset != 0) {
+			pr_err("FAIL: global stack canary found at offset %ld (canary for pid %d matches init_task's)!\n",
+			       init_offset, pid);
+		} else {
+			pr_warn("FAIL: did not correctly locate stack canary :(\n");
+			pr_expected_config(CONFIG_STACKPROTECTOR);
+		}
+
+		return;
+	} else if (init_offset != 0) {
+		pr_warn("WARNING: found both current and init_task canaries nearby?!\n");
+	}
+
+	canary = (unsigned long *)stack + current_offset;
+	if (stack_canary_pid == 0) {
+		stack_canary = *canary;
+		stack_canary_pid = pid;
+		stack_canary_offset = current_offset;
+		pr_info("Recorded stack canary for pid %d at offset %ld\n",
+			stack_canary_pid, stack_canary_offset);
+	} else if (pid == stack_canary_pid) {
+		pr_warn("ERROR: saw pid %d again -- please use a new pid\n", pid);
+	} else {
+		if (current_offset != stack_canary_offset) {
+			pr_warn("ERROR: canary offset changed from %ld to %ld!?\n",
+				stack_canary_offset, current_offset);
+			return;
+		}
+
+		if (*canary == stack_canary) {
+			pr_warn("FAIL: canary identical for pid %d and pid %d at offset %ld!\n",
+				stack_canary_pid, pid, current_offset);
+		} else {
+			pr_info("ok: stack canaries differ between pid %d and pid %d at offset %ld.\n",
+				stack_canary_pid, pid, current_offset);
+			/* Reset the test. */
+			stack_canary_pid = 0;
+		}
+	}
+}
+
+static void lkdtm_REPORT_STACK_CANARY(void)
+{
+	/* Use default char array length that triggers stack protection. */
+	char data[8] __aligned(sizeof(void *)) = { };
+
+	__lkdtm_REPORT_STACK_CANARY((void *)&data);
+}
+
+static void lkdtm_UNALIGNED_LOAD_STORE_WRITE(void)
 {
 	static u8 data[5] __attribute__((aligned(4))) = {1, 2, 3, 4, 5};
 	u32 *p;
@@ -166,21 +272,50 @@ 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_SMP_CALL_LOCKUP(void *unused)
+{
+	for (;;)
+		cpu_relax();
+}
+
+static void lkdtm_SMP_CALL_LOCKUP(void)
+{
+	unsigned int cpu, target;
+
+	cpus_read_lock();
+
+	cpu = get_cpu();
+	target = cpumask_any_but(cpu_online_mask, cpu);
+
+	if (target >= nr_cpu_ids) {
+		pr_err("FAIL: no other online CPUs\n");
+		goto out_put_cpus;
+	}
+
+	smp_call_function_single(target, __lkdtm_SMP_CALL_LOCKUP, NULL, 1);
+
+	pr_err("FAIL: did not hang\n");
+
+out_put_cpus:
+	put_cpu();
+	cpus_read_unlock();
+}
+
+static void lkdtm_SPINLOCKUP(void)
 {
 	/* Must be called twice to trigger. */
 	spin_lock(&lock_me_up);
@@ -188,16 +323,17 @@ void lkdtm_SPINLOCKUP(void)
 	__release(&lock_me_up);
 }
 
-void lkdtm_HUNG_TASK(void)
+static void __noreturn lkdtm_HUNG_TASK(void)
 {
 	set_current_state(TASK_UNINTERRUPTIBLE);
 	schedule();
+	BUG();
 }
 
-volatile unsigned int huge = INT_MAX - 2;
-volatile unsigned int ignored;
+static volatile unsigned int huge = INT_MAX - 2;
+static volatile unsigned int ignored;
 
-void lkdtm_OVERFLOW_SIGNED(void)
+static void lkdtm_OVERFLOW_SIGNED(void)
 {
 	int value;
 
@@ -212,7 +348,7 @@ void lkdtm_OVERFLOW_SIGNED(void)
 }
 
 
-void lkdtm_OVERFLOW_UNSIGNED(void)
+static void lkdtm_OVERFLOW_UNSIGNED(void)
 {
 	unsigned int value;
 
@@ -226,11 +362,11 @@ void lkdtm_OVERFLOW_UNSIGNED(void)
 	ignored = value;
 }
 
-/* Intentionally using old-style flex array definition of 1 byte. */
+/* Intentionally using unannotated flex array definition. */
 struct array_bounds_flex_array {
 	int one;
 	int two;
-	char data[1];
+	char data[];
 };
 
 struct array_bounds {
@@ -240,7 +376,7 @@ 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;
@@ -248,6 +384,11 @@ 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. */
@@ -257,7 +398,7 @@ void lkdtm_ARRAY_BOUNDS(void)
 	 * 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++)
+	for (i = 0; i < 2; i++)
 		not_checked->data[i] = 'A';
 
 	pr_info("Array access beyond bounds ...\n");
@@ -267,9 +408,53 @@ void lkdtm_ARRAY_BOUNDS(void)
 	kfree(not_checked);
 	kfree(checked);
 	pr_err("FAIL: survived array bounds overflow!\n");
+	if (IS_ENABLED(CONFIG_UBSAN_BOUNDS))
+		pr_expected_config(CONFIG_UBSAN_TRAP);
+	else
+		pr_expected_config(CONFIG_UBSAN_BOUNDS);
+}
+
+struct lkdtm_annotated {
+	unsigned long flags;
+	int count;
+	int array[] __counted_by(count);
+};
+
+static volatile int fam_count = 4;
+
+static void lkdtm_FAM_BOUNDS(void)
+{
+	struct lkdtm_annotated *inst;
+
+	inst = kzalloc(struct_size(inst, array, fam_count + 1), GFP_KERNEL);
+	if (!inst) {
+		pr_err("FAIL: could not allocate test struct!\n");
+		return;
+	}
+
+	inst->count = fam_count;
+	pr_info("Array access within bounds ...\n");
+	inst->array[1] = fam_count;
+	ignored = inst->array[1];
+
+	pr_info("Array access beyond bounds ...\n");
+	inst->array[fam_count] = fam_count;
+	ignored = inst->array[fam_count];
+
+	kfree(inst);
+
+	pr_err("FAIL: survived access of invalid flexible array member index!\n");
+
+	if (!IS_ENABLED(CONFIG_CC_HAS_COUNTED_BY))
+		pr_warn("This is expected since this %s was built with a compiler that does not support __counted_by\n",
+			lkdtm_kernel_info);
+	else 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:
@@ -305,11 +490,11 @@ void lkdtm_CORRUPT_LIST_ADD(void)
 		pr_err("Overwrite did not happen, but no BUG?!\n");
 	else {
 		pr_err("list_add() corruption not detected!\n");
-		pr_expected_config(CONFIG_DEBUG_LIST);
+		pr_expected_config(CONFIG_LIST_HARDENED);
 	}
 }
 
-void lkdtm_CORRUPT_LIST_DEL(void)
+static void lkdtm_CORRUPT_LIST_DEL(void)
 {
 	LIST_HEAD(test_head);
 	struct lkdtm_list item;
@@ -332,12 +517,12 @@ void lkdtm_CORRUPT_LIST_DEL(void)
 		pr_err("Overwrite did not happen, but no BUG?!\n");
 	else {
 		pr_err("list_del() corruption not detected!\n");
-		pr_expected_config(CONFIG_DEBUG_LIST);
+		pr_expected_config(CONFIG_LIST_HARDENED);
 	}
 }
 
 /* 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;
@@ -351,7 +536,7 @@ 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;
@@ -364,7 +549,7 @@ 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
@@ -399,6 +584,7 @@ void lkdtm_UNSET_SMEP(void)
 	 * the cr4 writing instruction.
 	 */
 	insn = (unsigned char *)native_write_cr4;
+	OPTIMIZER_HIDE_VAR(insn);
 	for (i = 0; i < MOV_CR4_DEPTH; i++) {
 		/* mov %rdi, %cr4 */
 		if (insn[i] == 0x0f && insn[i+1] == 0x22 && insn[i+2] == 0xe7)
@@ -430,7 +616,7 @@ 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)
 	/*
@@ -478,7 +664,7 @@ 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
@@ -507,52 +693,39 @@ noinline void lkdtm_CORRUPT_PAC(void)
 #endif
 }
 
-void lkdtm_FORTIFY_OBJECT(void)
-{
-	struct target {
-		char a[10];
-	} target[2] = {};
-	int result;
-
-	/*
-	 * Using volatile prevents the compiler from determining the value of
-	 * 'size' at compile time. Without that, we would get a compile error
-	 * rather than a runtime error.
-	 */
-	volatile int size = 11;
-
-	pr_info("trying to read past the end of a struct\n");
-
-	result = memcmp(&target[0], &target[1], size);
-
-	/* Print result to prevent the code from being eliminated */
-	pr_err("FAIL: fortify did not catch an object overread!\n"
-	       "\"%d\" was the memcmp result.\n", result);
-}
-
-void lkdtm_FORTIFY_SUBOBJECT(void)
-{
-	struct target {
-		char a[10];
-		char b[10];
-	} target;
-	char *src;
-
-	src = kmalloc(20, GFP_KERNEL);
-	strscpy(src, "over ten bytes", 20);
-
-	pr_info("trying to strcpy past the end of a member of a struct\n");
-
-	/*
-	 * strncpy(target.a, src, 20); will hit a compile error because the
-	 * compiler knows at build time that target.a < 20 bytes. Use strcpy()
-	 * to force a runtime error.
-	 */
-	strcpy(target.a, src);
-
-	/* Use target.a to prevent the code from being eliminated */
-	pr_err("FAIL: fortify did not catch an sub-object overrun!\n"
-	       "\"%s\" was copied.\n", target.a);
+static struct crashtype crashtypes[] = {
+	CRASHTYPE(PANIC),
+	CRASHTYPE(PANIC_STOP_IRQOFF),
+	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(SMP_CALL_LOCKUP),
+	CRASHTYPE(SPINLOCKUP),
+	CRASHTYPE(HUNG_TASK),
+	CRASHTYPE(OVERFLOW_SIGNED),
+	CRASHTYPE(OVERFLOW_UNSIGNED),
+	CRASHTYPE(ARRAY_BOUNDS),
+	CRASHTYPE(FAM_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),
+};
 
-	kfree(src);
-}
+struct crashtype_category bugs_crashtypes = {
+	.crashtypes = crashtypes,
+	.len	    = ARRAY_SIZE(crashtypes),
+};