lkdtm: split remaining logic bug tests to separate file

This splits all the remaining tests from lkdtm_core.c into the new
lkdtm_bugs.c file to help separate things better for readability.

Signed-off-by: Kees Cook <keescook@chromium.org>

1 files changed, 152 insertions, 0 deletions

diff --git a/drivers/misc/lkdtm_bugs.c b/drivers/misc/lkdtm_bugs.c
new file mode 100644
index 000000000000..e87071f9c003
--- /dev/null
+++ b/drivers/misc/lkdtm_bugs.c
@@ -0,0 +1,152 @@
+/*
+ * 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.
+ */
+#define pr_fmt(fmt) "lkdtm: " fmt
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+
+#include "lkdtm.h"
+
+/*
+ * 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 (CONFIG_FRAME_WARN / 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);
+
+static int recursive_loop(int remaining)
+{
+	char buf[REC_STACK_SIZE];
+
+	/* Make sure compiler does not optimize this away. */
+	memset(buf, (remaining & 0xff) | 0x1, REC_STACK_SIZE);
+	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();
+}
+
+void lkdtm_WARNING(void)
+{
+	WARN_ON(1);
+}
+
+void lkdtm_EXCEPTION(void)
+{
+	*((int *) 0) = 0;
+}
+
+void lkdtm_LOOP(void)
+{
+	for (;;)
+		;
+}
+
+void lkdtm_OVERFLOW(void)
+{
+	(void) recursive_loop(recur_count);
+}
+
+noinline void lkdtm_CORRUPT_STACK(void)
+{
+	/* Use default char array length that triggers stack protection. */
+	char data[8];
+
+	memset((void *)data, 0, 64);
+}
+
+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;
+}
+
+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();
+}
+
+void lkdtm_ATOMIC_UNDERFLOW(void)
+{
+	atomic_t under = ATOMIC_INIT(INT_MIN);
+
+	pr_info("attempting good atomic increment\n");
+	atomic_inc(&under);
+	atomic_dec(&under);
+
+	pr_info("attempting bad atomic underflow\n");
+	atomic_dec(&under);
+}
+
+void lkdtm_ATOMIC_OVERFLOW(void)
+{
+	atomic_t over = ATOMIC_INIT(INT_MAX);
+
+	pr_info("attempting good atomic decrement\n");
+	atomic_dec(&over);
+	atomic_inc(&over);
+
+	pr_info("attempting bad atomic overflow\n");
+	atomic_inc(&over);
+}