[linux-2.6-block.git] / drivers / misc / lkdtm_bugs.c

/*
 * 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);
}
Commit	Line	Data
00f496c4 KC	1	/*
	2	* This is for all the tests related to logic bugs (e.g. bad dereferences,
	3	* bad alignment, bad loops, bad locking, bad scheduling, deep stacks, and
	4	* lockups) along with other things that don't fit well into existing LKDTM
	5	* test source files.
	6	*/
00f496c4	7	#include "lkdtm.h"
6819d101	8	#include <linux/list.h>
ff86b300	9	#include <linux/refcount.h>
6d2e91a6	10	#include <linux/sched.h>
e22aa9d7 KC	11	#include <linux/sched/signal.h>
e22aa9d7 KC	12	#include <linux/uaccess.h>
00f496c4	13
6819d101 KC	14	struct lkdtm_list {
	15	struct list_head node;
	16	};
	17
00f496c4 KC	18	/*
	19	* Make sure our attempts to over run the kernel stack doesn't trigger
	20	* a compiler warning when CONFIG_FRAME_WARN is set. Then make sure we
	21	* recurse past the end of THREAD_SIZE by default.
	22	*/
	23	#if defined(CONFIG_FRAME_WARN) && (CONFIG_FRAME_WARN > 0)
	24	#define REC_STACK_SIZE (CONFIG_FRAME_WARN / 2)
	25	#else
	26	#define REC_STACK_SIZE (THREAD_SIZE / 8)
	27	#endif
	28	#define REC_NUM_DEFAULT ((THREAD_SIZE / REC_STACK_SIZE) * 2)
	29
	30	static int recur_count = REC_NUM_DEFAULT;
	31
	32	static DEFINE_SPINLOCK(lock_me_up);
	33
	34	static int recursive_loop(int remaining)
	35	{
	36	char buf[REC_STACK_SIZE];
	37
	38	/* Make sure compiler does not optimize this away. */
	39	memset(buf, (remaining & 0xff) \| 0x1, REC_STACK_SIZE);
	40	if (!remaining)
	41	return 0;
	42	else
	43	return recursive_loop(remaining - 1);
	44	}
	45
	46	/* If the depth is negative, use the default, otherwise keep parameter. */
	47	void __init lkdtm_bugs_init(int *recur_param)
	48	{
	49	if (*recur_param < 0)
	50	*recur_param = recur_count;
	51	else
	52	recur_count = *recur_param;
	53	}
	54
	55	void lkdtm_PANIC(void)
	56	{
	57	panic("dumptest");
	58	}
	59
	60	void lkdtm_BUG(void)
	61	{
	62	BUG();
	63	}
	64
	65	void lkdtm_WARNING(void)
	66	{
	67	WARN_ON(1);
	68	}
	69
	70	void lkdtm_EXCEPTION(void)
	71	{
9e18308a	72	((volatile int ) 0) = 0;
00f496c4 KC	73	}
	74
	75	void lkdtm_LOOP(void)
	76	{
	77	for (;;)
	78	;
	79	}
	80
	81	void lkdtm_OVERFLOW(void)
	82	{
	83	(void) recursive_loop(recur_count);
	84	}
	85
7a11a1d1 AB	86	static noinline void __lkdtm_CORRUPT_STACK(void *stack)
	87	{
	88	memset(stack, 'a', 64);
	89	}
	90
00f496c4 KC	91	noinline void lkdtm_CORRUPT_STACK(void)
	92	{
	93	/* Use default char array length that triggers stack protection. */
	94	char data[8];
7a11a1d1	95	__lkdtm_CORRUPT_STACK(&data);
00f496c4	96
c55d2400	97	pr_info("Corrupted stack with '%16s'...\n", data);
00f496c4 KC	98	}
	99
	100	void lkdtm_UNALIGNED_LOAD_STORE_WRITE(void)
	101	{
	102	static u8 data[5] __attribute__((aligned(4))) = {1, 2, 3, 4, 5};
	103	u32 *p;
	104	u32 val = 0x12345678;
	105
	106	p = (u32 *)(data + 1);
	107	if (*p == 0)
	108	val = 0x87654321;
	109	*p = val;
	110	}
	111
	112	void lkdtm_SOFTLOCKUP(void)
	113	{
	114	preempt_disable();
	115	for (;;)
	116	cpu_relax();
	117	}
	118
	119	void lkdtm_HARDLOCKUP(void)
	120	{
	121	local_irq_disable();
	122	for (;;)
	123	cpu_relax();
	124	}
	125
	126	void lkdtm_SPINLOCKUP(void)
	127	{
	128	/* Must be called twice to trigger. */
	129	spin_lock(&lock_me_up);
	130	/* Let sparse know we intended to exit holding the lock. */
	131	__release(&lock_me_up);
	132	}
	133
	134	void lkdtm_HUNG_TASK(void)
	135	{
	136	set_current_state(TASK_UNINTERRUPTIBLE);
	137	schedule();
	138	}
	139
ff86b300	140	void lkdtm_REFCOUNT_SATURATE_INC(void)
00f496c4	141	{
ff86b300	142	refcount_t over = REFCOUNT_INIT(UINT_MAX - 1);
00f496c4	143
ff86b300 KC	144	pr_info("attempting good refcount decrement\n");
	145	refcount_dec(&over);
	146	refcount_inc(&over);
00f496c4	147
ff86b300 KC	148	pr_info("attempting bad refcount inc overflow\n");
	149	refcount_inc(&over);
	150	refcount_inc(&over);
	151	if (refcount_read(&over) == UINT_MAX)
	152	pr_err("Correctly stayed saturated, but no BUG?!\n");
	153	else
	154	pr_err("Fail: refcount wrapped\n");
	155	}
	156
	157	void lkdtm_REFCOUNT_SATURATE_ADD(void)
	158	{
	159	refcount_t over = REFCOUNT_INIT(UINT_MAX - 1);
	160
	161	pr_info("attempting good refcount decrement\n");
	162	refcount_dec(&over);
	163	refcount_inc(&over);
	164
	165	pr_info("attempting bad refcount add overflow\n");
	166	refcount_add(2, &over);
	167	if (refcount_read(&over) == UINT_MAX)
	168	pr_err("Correctly stayed saturated, but no BUG?!\n");
	169	else
	170	pr_err("Fail: refcount wrapped\n");
	171	}
	172
	173	void lkdtm_REFCOUNT_ZERO_DEC(void)
	174	{
	175	refcount_t zero = REFCOUNT_INIT(1);
	176
	177	pr_info("attempting bad refcount decrement to zero\n");
	178	refcount_dec(&zero);
	179	if (refcount_read(&zero) == 0)
	180	pr_err("Stayed at zero, but no BUG?!\n");
	181	else
	182	pr_err("Fail: refcount went crazy\n");
00f496c4 KC	183	}
00f496c4 KC	184
ff86b300	185	void lkdtm_REFCOUNT_ZERO_SUB(void)
00f496c4	186	{
ff86b300 KC	187	refcount_t zero = REFCOUNT_INIT(1);
	188
	189	pr_info("attempting bad refcount subtract past zero\n");
	190	if (!refcount_sub_and_test(2, &zero))
	191	pr_info("wrap attempt was noticed\n");
	192	if (refcount_read(&zero) == 1)
	193	pr_err("Correctly stayed above 0, but no BUG?!\n");
	194	else
	195	pr_err("Fail: refcount wrapped\n");
	196	}
00f496c4	197
ff86b300 KC	198	void lkdtm_REFCOUNT_ZERO_INC(void)
	199	{
	200	refcount_t zero = REFCOUNT_INIT(0);
00f496c4	201
ff86b300 KC	202	pr_info("attempting bad refcount increment from zero\n");
	203	refcount_inc(&zero);
	204	if (refcount_read(&zero) == 0)
	205	pr_err("Stayed at zero, but no BUG?!\n");
	206	else
	207	pr_err("Fail: refcount went past zero\n");
	208	}
	209
	210	void lkdtm_REFCOUNT_ZERO_ADD(void)
	211	{
	212	refcount_t zero = REFCOUNT_INIT(0);
	213
	214	pr_info("attempting bad refcount addition from zero\n");
	215	refcount_add(2, &zero);
	216	if (refcount_read(&zero) == 0)
	217	pr_err("Stayed at zero, but no BUG?!\n");
	218	else
	219	pr_err("Fail: refcount went past zero\n");
00f496c4	220	}
6819d101 KC	221
	222	void lkdtm_CORRUPT_LIST_ADD(void)
	223	{
	224	/*
	225	* Initially, an empty list via LIST_HEAD:
	226	* test_head.next = &test_head
	227	* test_head.prev = &test_head
	228	*/
	229	LIST_HEAD(test_head);
	230	struct lkdtm_list good, bad;
	231	void *target[2] = { };
	232	void *redirection = &target;
	233
	234	pr_info("attempting good list addition\n");
	235
	236	/*
	237	* Adding to the list performs these actions:
	238	* test_head.next->prev = &good.node
	239	* good.node.next = test_head.next
	240	* good.node.prev = test_head
	241	* test_head.next = good.node
	242	*/
	243	list_add(&good.node, &test_head);
	244
	245	pr_info("attempting corrupted list addition\n");
	246	/*
	247	* In simulating this "write what where" primitive, the "what" is
	248	* the address of &bad.node, and the "where" is the address held
	249	* by "redirection".
	250	*/
	251	test_head.next = redirection;
	252	list_add(&bad.node, &test_head);
	253
	254	if (target[0] == NULL && target[1] == NULL)
	255	pr_err("Overwrite did not happen, but no BUG?!\n");
	256	else
	257	pr_err("list_add() corruption not detected!\n");
	258	}
	259
	260	void lkdtm_CORRUPT_LIST_DEL(void)
	261	{
	262	LIST_HEAD(test_head);
	263	struct lkdtm_list item;
	264	void *target[2] = { };
	265	void *redirection = &target;
	266
	267	list_add(&item.node, &test_head);
	268
	269	pr_info("attempting good list removal\n");
	270	list_del(&item.node);
	271
	272	pr_info("attempting corrupted list removal\n");
	273	list_add(&item.node, &test_head);
	274
	275	/* As with the list_add() test above, this corrupts "next". */
	276	item.node.next = redirection;
	277	list_del(&item.node);
	278
	279	if (target[0] == NULL && target[1] == NULL)
	280	pr_err("Overwrite did not happen, but no BUG?!\n");
	281	else
	282	pr_err("list_del() corruption not detected!\n");
	283	}
e22aa9d7 KC	284
	285	void lkdtm_CORRUPT_USER_DS(void)
	286	{
	287	pr_info("setting bad task size limit\n");
	288	set_fs(KERNEL_DS);
	289
	290	/* Make sure we do not keep running with a KERNEL_DS! */
	291	force_sig(SIGKILL, current);
	292	}