drivers/misc/lkdtm_bugs.c - kernel/msm-5.4 - Gitiles

 /*
  * 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/refcount.h>
 #include <linux/sched.h>
 #include <linux/sched/signal.h>
 #include <linux/uaccess.h>

 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 (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)
 {
 	*((volatile int *) 0) = 0;
 }

 void lkdtm_LOOP(void)
 {
 	for (;;)
 		;
 }

 void lkdtm_OVERFLOW(void)
 {
 	(void) recursive_loop(recur_count);
 }

 static noinline void __lkdtm_CORRUPT_STACK(void *stack)
 {
 	memset(stack, 'a', 64);
 }

 noinline void lkdtm_CORRUPT_STACK(void)
 {
 	/* Use default char array length that triggers stack protection. */
 	char data[8];
 	__lkdtm_CORRUPT_STACK(&data);

 	pr_info("Corrupted stack with '%16s'...\n", 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;
 }

 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_REFCOUNT_SATURATE_INC(void)
 {
 	refcount_t over = REFCOUNT_INIT(UINT_MAX - 1);

 	pr_info("attempting good refcount decrement\n");
 	refcount_dec(&over);
 	refcount_inc(&over);

 	pr_info("attempting bad refcount inc overflow\n");
 	refcount_inc(&over);
 	refcount_inc(&over);
 	if (refcount_read(&over) == UINT_MAX)
 		pr_err("Correctly stayed saturated, but no BUG?!\n");
 	else
 		pr_err("Fail: refcount wrapped\n");
 }

 void lkdtm_REFCOUNT_SATURATE_ADD(void)
 {
 	refcount_t over = REFCOUNT_INIT(UINT_MAX - 1);

 	pr_info("attempting good refcount decrement\n");
 	refcount_dec(&over);
 	refcount_inc(&over);

 	pr_info("attempting bad refcount add overflow\n");
 	refcount_add(2, &over);
 	if (refcount_read(&over) == UINT_MAX)
 		pr_err("Correctly stayed saturated, but no BUG?!\n");
 	else
 		pr_err("Fail: refcount wrapped\n");
 }

 void lkdtm_REFCOUNT_ZERO_DEC(void)
 {
 	refcount_t zero = REFCOUNT_INIT(1);

 	pr_info("attempting bad refcount decrement to zero\n");
 	refcount_dec(&zero);
 	if (refcount_read(&zero) == 0)
 		pr_err("Stayed at zero, but no BUG?!\n");
 	else
 		pr_err("Fail: refcount went crazy\n");
 }

 void lkdtm_REFCOUNT_ZERO_SUB(void)
 {
 	refcount_t zero = REFCOUNT_INIT(1);

 	pr_info("attempting bad refcount subtract past zero\n");
 	if (!refcount_sub_and_test(2, &zero))
 		pr_info("wrap attempt was noticed\n");
 	if (refcount_read(&zero) == 1)
 		pr_err("Correctly stayed above 0, but no BUG?!\n");
 	else
 		pr_err("Fail: refcount wrapped\n");
 }

 void lkdtm_REFCOUNT_ZERO_INC(void)
 {
 	refcount_t zero = REFCOUNT_INIT(0);

 	pr_info("attempting bad refcount increment from zero\n");
 	refcount_inc(&zero);
 	if (refcount_read(&zero) == 0)
 		pr_err("Stayed at zero, but no BUG?!\n");
 	else
 		pr_err("Fail: refcount went past zero\n");
 }

 void lkdtm_REFCOUNT_ZERO_ADD(void)
 {
 	refcount_t zero = REFCOUNT_INIT(0);

 	pr_info("attempting bad refcount addition from zero\n");
 	refcount_add(2, &zero);
 	if (refcount_read(&zero) == 0)
 		pr_err("Stayed at zero, but no BUG?!\n");
 	else
 		pr_err("Fail: refcount went past zero\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");
 }

 void lkdtm_CORRUPT_USER_DS(void)
 {
 	pr_info("setting bad task size limit\n");
 	set_fs(KERNEL_DS);

 	/* Make sure we do not keep running with a KERNEL_DS! */
 	force_sig(SIGKILL, current);
 }
	/*
	* 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/refcount.h>
	#include <linux/sched.h>
	#include <linux/sched/signal.h>
	#include <linux/uaccess.h>

	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 (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)
	{
	((volatile int ) 0) = 0;
	}

	void lkdtm_LOOP(void)
	{
	for (;;)
	;
	}

	void lkdtm_OVERFLOW(void)
	{
	(void) recursive_loop(recur_count);
	}

	static noinline void __lkdtm_CORRUPT_STACK(void *stack)
	{
	memset(stack, 'a', 64);
	}

	noinline void lkdtm_CORRUPT_STACK(void)
	{
	/* Use default char array length that triggers stack protection. */
	char data[8];
	__lkdtm_CORRUPT_STACK(&data);

	pr_info("Corrupted stack with '%16s'...\n", 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;
	}

	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_REFCOUNT_SATURATE_INC(void)
	{
	refcount_t over = REFCOUNT_INIT(UINT_MAX - 1);

	pr_info("attempting good refcount decrement\n");
	refcount_dec(&over);
	refcount_inc(&over);

	pr_info("attempting bad refcount inc overflow\n");
	refcount_inc(&over);
	refcount_inc(&over);
	if (refcount_read(&over) == UINT_MAX)
	pr_err("Correctly stayed saturated, but no BUG?!\n");
	else
	pr_err("Fail: refcount wrapped\n");
	}

	void lkdtm_REFCOUNT_SATURATE_ADD(void)
	{
	refcount_t over = REFCOUNT_INIT(UINT_MAX - 1);

	pr_info("attempting good refcount decrement\n");
	refcount_dec(&over);
	refcount_inc(&over);

	pr_info("attempting bad refcount add overflow\n");
	refcount_add(2, &over);
	if (refcount_read(&over) == UINT_MAX)
	pr_err("Correctly stayed saturated, but no BUG?!\n");
	else
	pr_err("Fail: refcount wrapped\n");
	}

	void lkdtm_REFCOUNT_ZERO_DEC(void)
	{
	refcount_t zero = REFCOUNT_INIT(1);

	pr_info("attempting bad refcount decrement to zero\n");
	refcount_dec(&zero);
	if (refcount_read(&zero) == 0)
	pr_err("Stayed at zero, but no BUG?!\n");
	else
	pr_err("Fail: refcount went crazy\n");
	}

	void lkdtm_REFCOUNT_ZERO_SUB(void)
	{
	refcount_t zero = REFCOUNT_INIT(1);

	pr_info("attempting bad refcount subtract past zero\n");
	if (!refcount_sub_and_test(2, &zero))
	pr_info("wrap attempt was noticed\n");
	if (refcount_read(&zero) == 1)
	pr_err("Correctly stayed above 0, but no BUG?!\n");
	else
	pr_err("Fail: refcount wrapped\n");
	}

	void lkdtm_REFCOUNT_ZERO_INC(void)
	{
	refcount_t zero = REFCOUNT_INIT(0);

	pr_info("attempting bad refcount increment from zero\n");
	refcount_inc(&zero);
	if (refcount_read(&zero) == 0)
	pr_err("Stayed at zero, but no BUG?!\n");
	else
	pr_err("Fail: refcount went past zero\n");
	}

	void lkdtm_REFCOUNT_ZERO_ADD(void)
	{
	refcount_t zero = REFCOUNT_INIT(0);

	pr_info("attempting bad refcount addition from zero\n");
	refcount_add(2, &zero);
	if (refcount_read(&zero) == 0)
	pr_err("Stayed at zero, but no BUG?!\n");
	else
	pr_err("Fail: refcount went past zero\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");
	}

	void lkdtm_CORRUPT_USER_DS(void)
	{
	pr_info("setting bad task size limit\n");
	set_fs(KERNEL_DS);

	/* Make sure we do not keep running with a KERNEL_DS! */
	force_sig(SIGKILL, current);
	}