[linux-block.git] / drivers / misc / lkdtm / core.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Linux Kernel Dump Test Module for testing kernel crashes conditions:
 * induces system failures at predefined crashpoints and under predefined
 * operational conditions in order to evaluate the reliability of kernel
 * sanity checking and crash dumps obtained using different dumping
 * solutions.
 *
 * Copyright (C) IBM Corporation, 2006
 *
 * Author: Ankita Garg <ankita@in.ibm.com>
 *
 * It is adapted from the Linux Kernel Dump Test Tool by
 * Fernando Luis Vazquez Cao <http://lkdtt.sourceforge.net>
 *
 * Debugfs support added by Simon Kagstrom <simon.kagstrom@netinsight.net>
 *
 * See Documentation/fault-injection/provoke-crashes.txt for instructions
 */
#include "lkdtm.h"
#include <linux/fs.h>
#include <linux/module.h>
#include <linux/buffer_head.h>
#include <linux/kprobes.h>
#include <linux/list.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/debugfs.h>

#define DEFAULT_COUNT 10

static int lkdtm_debugfs_open(struct inode *inode, struct file *file);
static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
		size_t count, loff_t *off);
static ssize_t direct_entry(struct file *f, const char __user *user_buf,
			    size_t count, loff_t *off);

#ifdef CONFIG_KPROBES
static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs);
static ssize_t lkdtm_debugfs_entry(struct file *f,
				   const char __user *user_buf,
				   size_t count, loff_t *off);
# define CRASHPOINT_KPROBE(_symbol)				\
		.kprobe = {					\
			.symbol_name = (_symbol),		\
			.pre_handler = lkdtm_kprobe_handler,	\
		},
# define CRASHPOINT_WRITE(_symbol)				\
		(_symbol) ? lkdtm_debugfs_entry : direct_entry
#else
# define CRASHPOINT_KPROBE(_symbol)
# define CRASHPOINT_WRITE(_symbol)		direct_entry
#endif

/* Crash points */
struct crashpoint {
	const char *name;
	const struct file_operations fops;
	struct kprobe kprobe;
};

#define CRASHPOINT(_name, _symbol)				\
	{							\
		.name = _name,					\
		.fops = {					\
			.read	= lkdtm_debugfs_read,		\
			.llseek	= generic_file_llseek,		\
			.open	= lkdtm_debugfs_open,		\
			.write	= CRASHPOINT_WRITE(_symbol)	\
		},						\
		CRASHPOINT_KPROBE(_symbol)			\
	}

/* Define the possible places where we can trigger a crash point. */
static struct crashpoint crashpoints[] = {
	CRASHPOINT("DIRECT",		 NULL),
#ifdef CONFIG_KPROBES
	CRASHPOINT("INT_HARDWARE_ENTRY", "do_IRQ"),
	CRASHPOINT("INT_HW_IRQ_EN",	 "handle_irq_event"),
	CRASHPOINT("INT_TASKLET_ENTRY",	 "tasklet_action"),
	CRASHPOINT("FS_DEVRW",		 "ll_rw_block"),
	CRASHPOINT("MEM_SWAPOUT",	 "shrink_inactive_list"),
	CRASHPOINT("TIMERADD",		 "hrtimer_start"),
	CRASHPOINT("SCSI_DISPATCH_CMD",	 "scsi_dispatch_cmd"),
	CRASHPOINT("IDE_CORE_CP",	 "generic_ide_ioctl"),
#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(EXCEPTION),
	CRASHTYPE(LOOP),
	CRASHTYPE(OVERFLOW),
	CRASHTYPE(CORRUPT_LIST_ADD),
	CRASHTYPE(CORRUPT_LIST_DEL),
	CRASHTYPE(CORRUPT_USER_DS),
	CRASHTYPE(CORRUPT_STACK),
	CRASHTYPE(CORRUPT_STACK_STRONG),
	CRASHTYPE(STACK_GUARD_PAGE_LEADING),
	CRASHTYPE(STACK_GUARD_PAGE_TRAILING),
	CRASHTYPE(UNALIGNED_LOAD_STORE_WRITE),
	CRASHTYPE(OVERWRITE_ALLOCATION),
	CRASHTYPE(WRITE_AFTER_FREE),
	CRASHTYPE(READ_AFTER_FREE),
	CRASHTYPE(WRITE_BUDDY_AFTER_FREE),
	CRASHTYPE(READ_BUDDY_AFTER_FREE),
	CRASHTYPE(SOFTLOCKUP),
	CRASHTYPE(HARDLOCKUP),
	CRASHTYPE(SPINLOCKUP),
	CRASHTYPE(HUNG_TASK),
	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(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(USERCOPY_KERNEL_DS),
	CRASHTYPE(STACKLEAK_ERASING),
};


/* Global kprobe entry and crashtype. */
static struct kprobe *lkdtm_kprobe;
static struct crashpoint *lkdtm_crashpoint;
static const struct crashtype *lkdtm_crashtype;

/* Module parameters */
static int recur_count = -1;
module_param(recur_count, int, 0644);
MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test");

static char* cpoint_name;
module_param(cpoint_name, charp, 0444);
MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");

static char* cpoint_type;
module_param(cpoint_type, charp, 0444);
MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
				"hitting the crash point");

static int cpoint_count = DEFAULT_COUNT;
module_param(cpoint_count, int, 0644);
MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
				"crash point is to be hit to trigger action");


/* Return the crashtype number or NULL if the name is invalid */
static const struct crashtype *find_crashtype(const char *name)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
		if (!strcmp(name, crashtypes[i].name))
			return &crashtypes[i];
	}

	return NULL;
}

/*
 * This is forced noinline just so it distinctly shows up in the stackdump
 * which makes validation of expected lkdtm crashes easier.
 */
static noinline void lkdtm_do_action(const struct crashtype *crashtype)
{
	if (WARN_ON(!crashtype || !crashtype->func))
		return;
	crashtype->func();
}

static int lkdtm_register_cpoint(struct crashpoint *crashpoint,
				 const struct crashtype *crashtype)
{
	int ret;

	/* If this doesn't have a symbol, just call immediately. */
	if (!crashpoint->kprobe.symbol_name) {
		lkdtm_do_action(crashtype);
		return 0;
	}

	if (lkdtm_kprobe != NULL)
		unregister_kprobe(lkdtm_kprobe);

	lkdtm_crashpoint = crashpoint;
	lkdtm_crashtype = crashtype;
	lkdtm_kprobe = &crashpoint->kprobe;
	ret = register_kprobe(lkdtm_kprobe);
	if (ret < 0) {
		pr_info("Couldn't register kprobe %s\n",
			crashpoint->kprobe.symbol_name);
		lkdtm_kprobe = NULL;
		lkdtm_crashpoint = NULL;
		lkdtm_crashtype = NULL;
	}

	return ret;
}

#ifdef CONFIG_KPROBES
/* Global crash counter and spinlock. */
static int crash_count = DEFAULT_COUNT;
static DEFINE_SPINLOCK(crash_count_lock);

/* Called by kprobe entry points. */
static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs)
{
	unsigned long flags;
	bool do_it = false;

	if (WARN_ON(!lkdtm_crashpoint || !lkdtm_crashtype))
		return 0;

	spin_lock_irqsave(&crash_count_lock, flags);
	crash_count--;
	pr_info("Crash point %s of type %s hit, trigger in %d rounds\n",
		lkdtm_crashpoint->name, lkdtm_crashtype->name, crash_count);

	if (crash_count == 0) {
		do_it = true;
		crash_count = cpoint_count;
	}
	spin_unlock_irqrestore(&crash_count_lock, flags);

	if (do_it)
		lkdtm_do_action(lkdtm_crashtype);

	return 0;
}

static ssize_t lkdtm_debugfs_entry(struct file *f,
				   const char __user *user_buf,
				   size_t count, loff_t *off)
{
	struct crashpoint *crashpoint = file_inode(f)->i_private;
	const struct crashtype *crashtype = NULL;
	char *buf;
	int err;

	if (count >= PAGE_SIZE)
		return -EINVAL;

	buf = (char *)__get_free_page(GFP_KERNEL);
	if (!buf)
		return -ENOMEM;
	if (copy_from_user(buf, user_buf, count)) {
		free_page((unsigned long) buf);
		return -EFAULT;
	}
	/* NULL-terminate and remove enter */
	buf[count] = '\0';
	strim(buf);

	crashtype = find_crashtype(buf);
	free_page((unsigned long)buf);

	if (!crashtype)
		return -EINVAL;

	err = lkdtm_register_cpoint(crashpoint, crashtype);
	if (err < 0)
		return err;

	*off += count;

	return count;
}
#endif

/* Generic read callback that just prints out the available crash types */
static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
		size_t count, loff_t *off)
{
	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);
	}
	buf[n] = '\0';

	out = simple_read_from_buffer(user_buf, count, off,
				      buf, n);
	free_page((unsigned long) buf);

	return out;
}

static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
{
	return 0;
}

/* Special entry to just crash directly. Available without KPROBEs */
static ssize_t direct_entry(struct file *f, const char __user *user_buf,
		size_t count, loff_t *off)
{
	const struct crashtype *crashtype;
	char *buf;

	if (count >= PAGE_SIZE)
		return -EINVAL;
	if (count < 1)
		return -EINVAL;

	buf = (char *)__get_free_page(GFP_KERNEL);
	if (!buf)
		return -ENOMEM;
	if (copy_from_user(buf, user_buf, count)) {
		free_page((unsigned long) buf);
		return -EFAULT;
	}
	/* NULL-terminate and remove enter */
	buf[count] = '\0';
	strim(buf);

	crashtype = find_crashtype(buf);
	free_page((unsigned long) buf);
	if (!crashtype)
		return -EINVAL;

	pr_info("Performing direct entry %s\n", crashtype->name);
	lkdtm_do_action(crashtype);
	*off += count;

	return count;
}

static struct dentry *lkdtm_debugfs_root;

static int __init lkdtm_module_init(void)
{
	struct crashpoint *crashpoint = NULL;
	const struct crashtype *crashtype = NULL;
	int ret = -EINVAL;
	int i;

	/* Neither or both of these need to be set */
	if ((cpoint_type || cpoint_name) && !(cpoint_type && cpoint_name)) {
		pr_err("Need both cpoint_type and cpoint_name or neither\n");
		return -EINVAL;
	}

	if (cpoint_type) {
		crashtype = find_crashtype(cpoint_type);
		if (!crashtype) {
			pr_err("Unknown crashtype '%s'\n", cpoint_type);
			return -EINVAL;
		}
	}

	if (cpoint_name) {
		for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
			if (!strcmp(cpoint_name, crashpoints[i].name))
				crashpoint = &crashpoints[i];
		}

		/* Refuse unknown crashpoints. */
		if (!crashpoint) {
			pr_err("Invalid crashpoint %s\n", cpoint_name);
			return -EINVAL;
		}
	}

#ifdef CONFIG_KPROBES
	/* Set crash count. */
	crash_count = cpoint_count;
#endif

	/* Handle test-specific initialization. */
	lkdtm_bugs_init(&recur_count);
	lkdtm_perms_init();
	lkdtm_usercopy_init();

	/* Register debugfs interface */
	lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
	if (!lkdtm_debugfs_root) {
		pr_err("creating root dir failed\n");
		return -ENODEV;
	}

	/* Install debugfs trigger files. */
	for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
		struct crashpoint *cur = &crashpoints[i];
		struct dentry *de;

		de = debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root,
					 cur, &cur->fops);
		if (de == NULL) {
			pr_err("could not create crashpoint %s\n", cur->name);
			goto out_err;
		}
	}

	/* Install crashpoint if one was selected. */
	if (crashpoint) {
		ret = lkdtm_register_cpoint(crashpoint, crashtype);
		if (ret < 0) {
			pr_info("Invalid crashpoint %s\n", crashpoint->name);
			goto out_err;
		}
		pr_info("Crash point %s of type %s registered\n",
			crashpoint->name, cpoint_type);
	} else {
		pr_info("No crash points registered, enable through debugfs\n");
	}

	return 0;

out_err:
	debugfs_remove_recursive(lkdtm_debugfs_root);
	return ret;
}

static void __exit lkdtm_module_exit(void)
{
	debugfs_remove_recursive(lkdtm_debugfs_root);

	/* Handle test-specific clean-up. */
	lkdtm_usercopy_exit();

	if (lkdtm_kprobe != NULL)
		unregister_kprobe(lkdtm_kprobe);

	pr_info("Crash point unregistered\n");
}

module_init(lkdtm_module_init);
module_exit(lkdtm_module_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Kernel crash testing module");
Commit	Line	Data
1a59d1b8	1	// SPDX-License-Identifier: GPL-2.0-or-later
8bb31b9d	2	/*
426f3a53 KC	3	* Linux Kernel Dump Test Module for testing kernel crashes conditions:
	4	* induces system failures at predefined crashpoints and under predefined
	5	* operational conditions in order to evaluate the reliability of kernel
	6	* sanity checking and crash dumps obtained using different dumping
	7	* solutions.
8bb31b9d	8	*
8bb31b9d AG	9	* Copyright (C) IBM Corporation, 2006
	10	*
	11	* Author: Ankita Garg <ankita@in.ibm.com>
	12	*
8bb31b9d AG	13	* It is adapted from the Linux Kernel Dump Test Tool by
	14	* Fernando Luis Vazquez Cao <http://lkdtt.sourceforge.net>
	15	*
0347af4e	16	* Debugfs support added by Simon Kagstrom <simon.kagstrom@netinsight.net>
8bb31b9d	17	*
0347af4e	18	* See Documentation/fault-injection/provoke-crashes.txt for instructions
8bb31b9d	19	*/
6d2e91a6	20	#include "lkdtm.h"
5d861d92	21	#include <linux/fs.h>
8bb31b9d	22	#include <linux/module.h>
5d861d92	23	#include <linux/buffer_head.h>
8bb31b9d	24	#include <linux/kprobes.h>
5d861d92	25	#include <linux/list.h>
8bb31b9d	26	#include <linux/init.h>
5a0e3ad6	27	#include <linux/slab.h>
0347af4e	28	#include <linux/debugfs.h>
8bb31b9d	29
d87c9788 KC	30	#define DEFAULT_COUNT 10
d87c9788 KC	31
c479e3fd KC	32	static int lkdtm_debugfs_open(struct inode inode, struct file file);
	33	static ssize_t lkdtm_debugfs_read(struct file f, char __user user_buf,
	34	size_t count, loff_t *off);
	35	static ssize_t direct_entry(struct file f, const char __user user_buf,
	36	size_t count, loff_t *off);
2b271cb7 AB	37
2b271cb7 AB	38	#ifdef CONFIG_KPROBES
31c5c870	39	static int lkdtm_kprobe_handler(struct kprobe kp, struct pt_regs regs);
c479e3fd KC	40	static ssize_t lkdtm_debugfs_entry(struct file *f,
	41	const char __user *user_buf,
	42	size_t count, loff_t *off);
31c5c870 KC	43	# define CRASHPOINT_KPROBE(_symbol) \
	44	.kprobe = { \
	45	.symbol_name = (_symbol), \
	46	.pre_handler = lkdtm_kprobe_handler, \
	47	},
	48	# define CRASHPOINT_WRITE(_symbol) \
	49	(_symbol) ? lkdtm_debugfs_entry : direct_entry
	50	#else
	51	# define CRASHPOINT_KPROBE(_symbol)
	52	# define CRASHPOINT_WRITE(_symbol) direct_entry
f2c6edc1 KC	53	#endif
f2c6edc1 KC	54
c479e3fd KC	55	/* Crash points */
	56	struct crashpoint {
	57	const char *name;
	58	const struct file_operations fops;
31c5c870	59	struct kprobe kprobe;
8bb31b9d AG	60	};
8bb31b9d AG	61
31c5c870	62	#define CRASHPOINT(_name, _symbol) \
c479e3fd KC	63	{ \
	64	.name = _name, \
	65	.fops = { \
	66	.read = lkdtm_debugfs_read, \
	67	.llseek = generic_file_llseek, \
	68	.open = lkdtm_debugfs_open, \
31c5c870	69	.write = CRASHPOINT_WRITE(_symbol) \
c479e3fd	70	}, \
31c5c870	71	CRASHPOINT_KPROBE(_symbol) \
c479e3fd KC	72	}
	73
	74	/* Define the possible places where we can trigger a crash point. */
31c5c870 KC	75	static struct crashpoint crashpoints[] = {
31c5c870 KC	76	CRASHPOINT("DIRECT", NULL),
c479e3fd	77	#ifdef CONFIG_KPROBES
31c5c870	78	CRASHPOINT("INT_HARDWARE_ENTRY", "do_IRQ"),
5be2a501	79	CRASHPOINT("INT_HW_IRQ_EN", "handle_irq_event"),
31c5c870 KC	80	CRASHPOINT("INT_TASKLET_ENTRY", "tasklet_action"),
	81	CRASHPOINT("FS_DEVRW", "ll_rw_block"),
	82	CRASHPOINT("MEM_SWAPOUT", "shrink_inactive_list"),
	83	CRASHPOINT("TIMERADD", "hrtimer_start"),
	84	CRASHPOINT("SCSI_DISPATCH_CMD", "scsi_dispatch_cmd"),
31c5c870	85	CRASHPOINT("IDE_CORE_CP", "generic_ide_ioctl"),
c479e3fd	86	#endif
8bb31b9d AG	87	};
8bb31b9d AG	88
c479e3fd KC	89
	90	/* Crash types. */
	91	struct crashtype {
	92	const char *name;
	93	void (*func)(void);
8bb31b9d AG	94	};
8bb31b9d AG	95
c479e3fd KC	96	#define CRASHTYPE(_name) \
	97	{ \
	98	.name = __stringify(_name), \
	99	.func = lkdtm_ ## _name, \
	100	}
	101
	102	/* Define the possible types of crashes that can be triggered. */
75f98b7a	103	static const struct crashtype crashtypes[] = {
c479e3fd KC	104	CRASHTYPE(PANIC),
	105	CRASHTYPE(BUG),
	106	CRASHTYPE(WARNING),
	107	CRASHTYPE(EXCEPTION),
	108	CRASHTYPE(LOOP),
	109	CRASHTYPE(OVERFLOW),
6819d101 KC	110	CRASHTYPE(CORRUPT_LIST_ADD),
6819d101 KC	111	CRASHTYPE(CORRUPT_LIST_DEL),
e22aa9d7	112	CRASHTYPE(CORRUPT_USER_DS),
c479e3fd	113	CRASHTYPE(CORRUPT_STACK),
93e78c6b	114	CRASHTYPE(CORRUPT_STACK_STRONG),
7b25a85c KC	115	CRASHTYPE(STACK_GUARD_PAGE_LEADING),
7b25a85c KC	116	CRASHTYPE(STACK_GUARD_PAGE_TRAILING),
c479e3fd KC	117	CRASHTYPE(UNALIGNED_LOAD_STORE_WRITE),
	118	CRASHTYPE(OVERWRITE_ALLOCATION),
	119	CRASHTYPE(WRITE_AFTER_FREE),
	120	CRASHTYPE(READ_AFTER_FREE),
	121	CRASHTYPE(WRITE_BUDDY_AFTER_FREE),
	122	CRASHTYPE(READ_BUDDY_AFTER_FREE),
	123	CRASHTYPE(SOFTLOCKUP),
	124	CRASHTYPE(HARDLOCKUP),
	125	CRASHTYPE(SPINLOCKUP),
	126	CRASHTYPE(HUNG_TASK),
	127	CRASHTYPE(EXEC_DATA),
	128	CRASHTYPE(EXEC_STACK),
	129	CRASHTYPE(EXEC_KMALLOC),
	130	CRASHTYPE(EXEC_VMALLOC),
	131	CRASHTYPE(EXEC_RODATA),
	132	CRASHTYPE(EXEC_USERSPACE),
59a12205	133	CRASHTYPE(EXEC_NULL),
c479e3fd	134	CRASHTYPE(ACCESS_USERSPACE),
59a12205	135	CRASHTYPE(ACCESS_NULL),
c479e3fd KC	136	CRASHTYPE(WRITE_RO),
	137	CRASHTYPE(WRITE_RO_AFTER_INIT),
	138	CRASHTYPE(WRITE_KERN),
95925c99 KC	139	CRASHTYPE(REFCOUNT_INC_OVERFLOW),
	140	CRASHTYPE(REFCOUNT_ADD_OVERFLOW),
	141	CRASHTYPE(REFCOUNT_INC_NOT_ZERO_OVERFLOW),
	142	CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_OVERFLOW),
	143	CRASHTYPE(REFCOUNT_DEC_ZERO),
	144	CRASHTYPE(REFCOUNT_DEC_NEGATIVE),
	145	CRASHTYPE(REFCOUNT_DEC_AND_TEST_NEGATIVE),
	146	CRASHTYPE(REFCOUNT_SUB_AND_TEST_NEGATIVE),
	147	CRASHTYPE(REFCOUNT_INC_ZERO),
	148	CRASHTYPE(REFCOUNT_ADD_ZERO),
	149	CRASHTYPE(REFCOUNT_INC_SATURATED),
	150	CRASHTYPE(REFCOUNT_DEC_SATURATED),
	151	CRASHTYPE(REFCOUNT_ADD_SATURATED),
	152	CRASHTYPE(REFCOUNT_INC_NOT_ZERO_SATURATED),
	153	CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_SATURATED),
	154	CRASHTYPE(REFCOUNT_DEC_AND_TEST_SATURATED),
	155	CRASHTYPE(REFCOUNT_SUB_AND_TEST_SATURATED),
c7fea488 KC	156	CRASHTYPE(REFCOUNT_TIMING),
c7fea488 KC	157	CRASHTYPE(ATOMIC_TIMING),
c479e3fd KC	158	CRASHTYPE(USERCOPY_HEAP_SIZE_TO),
c479e3fd KC	159	CRASHTYPE(USERCOPY_HEAP_SIZE_FROM),
e47e3118 KC	160	CRASHTYPE(USERCOPY_HEAP_WHITELIST_TO),
e47e3118 KC	161	CRASHTYPE(USERCOPY_HEAP_WHITELIST_FROM),
c479e3fd KC	162	CRASHTYPE(USERCOPY_STACK_FRAME_TO),
	163	CRASHTYPE(USERCOPY_STACK_FRAME_FROM),
	164	CRASHTYPE(USERCOPY_STACK_BEYOND),
	165	CRASHTYPE(USERCOPY_KERNEL),
bef45902	166	CRASHTYPE(USERCOPY_KERNEL_DS),
f90d1e0c	167	CRASHTYPE(STACKLEAK_ERASING),
8bb31b9d AG	168	};
8bb31b9d AG	169
c479e3fd	170
31c5c870 KC	171	/* Global kprobe entry and crashtype. */
31c5c870 KC	172	static struct kprobe *lkdtm_kprobe;
75f98b7a KC	173	static struct crashpoint *lkdtm_crashpoint;
75f98b7a KC	174	static const struct crashtype *lkdtm_crashtype;
8bb31b9d	175
d87c9788 KC	176	/* Module parameters */
d87c9788 KC	177	static int recur_count = -1;
8bb31b9d	178	module_param(recur_count, int, 0644);
7d196ac3	179	MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test");
d87c9788 KC	180
d87c9788 KC	181	static char* cpoint_name;
dca41306	182	module_param(cpoint_name, charp, 0444);
5d861d92	183	MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
d87c9788 KC	184
d87c9788 KC	185	static char* cpoint_type;
dca41306	186	module_param(cpoint_type, charp, 0444);
5d861d92 RD	187	MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
5d861d92 RD	188	"hitting the crash point");
d87c9788 KC	189
d87c9788 KC	190	static int cpoint_count = DEFAULT_COUNT;
5d861d92 RD	191	module_param(cpoint_count, int, 0644);
	192	MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
	193	"crash point is to be hit to trigger action");
8bb31b9d	194
0347af4e	195
c479e3fd	196	/* Return the crashtype number or NULL if the name is invalid */
75f98b7a	197	static const struct crashtype find_crashtype(const char name)
8bb31b9d AG	198	{
8bb31b9d AG	199	int i;
0347af4e	200
c479e3fd KC	201	for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
	202	if (!strcmp(name, crashtypes[i].name))
	203	return &crashtypes[i];
8bb31b9d AG	204	}
8bb31b9d AG	205
c479e3fd	206	return NULL;
8bb31b9d AG	207	}
8bb31b9d AG	208
c479e3fd KC	209	/*
	210	* This is forced noinline just so it distinctly shows up in the stackdump
	211	* which makes validation of expected lkdtm crashes easier.
	212	*/
75f98b7a	213	static noinline void lkdtm_do_action(const struct crashtype *crashtype)
8bb31b9d	214	{
31c5c870 KC	215	if (WARN_ON(!crashtype \|\| !crashtype->func))
31c5c870 KC	216	return;
c479e3fd	217	crashtype->func();
0347af4e SK	218	}
0347af4e SK	219
c479e3fd	220	static int lkdtm_register_cpoint(struct crashpoint *crashpoint,
75f98b7a	221	const struct crashtype *crashtype)
8bb31b9d AG	222	{
	223	int ret;
	224
c479e3fd	225	/* If this doesn't have a symbol, just call immediately. */
31c5c870	226	if (!crashpoint->kprobe.symbol_name) {
c479e3fd	227	lkdtm_do_action(crashtype);
0347af4e	228	return 0;
8bb31b9d AG	229	}
8bb31b9d AG	230
31c5c870 KC	231	if (lkdtm_kprobe != NULL)
31c5c870 KC	232	unregister_kprobe(lkdtm_kprobe);
c479e3fd KC	233
	234	lkdtm_crashpoint = crashpoint;
	235	lkdtm_crashtype = crashtype;
31c5c870 KC	236	lkdtm_kprobe = &crashpoint->kprobe;
31c5c870 KC	237	ret = register_kprobe(lkdtm_kprobe);
c479e3fd	238	if (ret < 0) {
31c5c870 KC	239	pr_info("Couldn't register kprobe %s\n",
	240	crashpoint->kprobe.symbol_name);
	241	lkdtm_kprobe = NULL;
c479e3fd KC	242	lkdtm_crashpoint = NULL;
c479e3fd KC	243	lkdtm_crashtype = NULL;
0347af4e SK	244	}
	245
	246	return ret;
	247	}
	248
2b271cb7 AB	249	#ifdef CONFIG_KPROBES
	250	/* Global crash counter and spinlock. */
	251	static int crash_count = DEFAULT_COUNT;
	252	static DEFINE_SPINLOCK(crash_count_lock);
	253
31c5c870 KC	254	/* Called by kprobe entry points. */
31c5c870 KC	255	static int lkdtm_kprobe_handler(struct kprobe kp, struct pt_regs regs)
2b271cb7 AB	256	{
	257	unsigned long flags;
	258	bool do_it = false;
	259
31c5c870 KC	260	if (WARN_ON(!lkdtm_crashpoint \|\| !lkdtm_crashtype))
31c5c870 KC	261	return 0;
2b271cb7 AB	262
	263	spin_lock_irqsave(&crash_count_lock, flags);
	264	crash_count--;
	265	pr_info("Crash point %s of type %s hit, trigger in %d rounds\n",
	266	lkdtm_crashpoint->name, lkdtm_crashtype->name, crash_count);
	267
	268	if (crash_count == 0) {
	269	do_it = true;
	270	crash_count = cpoint_count;
	271	}
	272	spin_unlock_irqrestore(&crash_count_lock, flags);
	273
	274	if (do_it)
	275	lkdtm_do_action(lkdtm_crashtype);
31c5c870 KC	276
31c5c870 KC	277	return 0;
2b271cb7 AB	278	}
2b271cb7 AB	279
c479e3fd KC	280	static ssize_t lkdtm_debugfs_entry(struct file *f,
	281	const char __user *user_buf,
	282	size_t count, loff_t *off)
0347af4e	283	{
c479e3fd	284	struct crashpoint *crashpoint = file_inode(f)->i_private;
75f98b7a	285	const struct crashtype *crashtype = NULL;
0347af4e SK	286	char *buf;
	287	int err;
	288
	289	if (count >= PAGE_SIZE)
	290	return -EINVAL;
	291
	292	buf = (char *)__get_free_page(GFP_KERNEL);
	293	if (!buf)
	294	return -ENOMEM;
	295	if (copy_from_user(buf, user_buf, count)) {
	296	free_page((unsigned long) buf);
	297	return -EFAULT;
	298	}
	299	/* NULL-terminate and remove enter */
	300	buf[count] = '\0';
	301	strim(buf);
	302
c479e3fd KC	303	crashtype = find_crashtype(buf);
c479e3fd KC	304	free_page((unsigned long)buf);
0347af4e	305
c479e3fd	306	if (!crashtype)
0347af4e SK	307	return -EINVAL;
0347af4e SK	308
c479e3fd	309	err = lkdtm_register_cpoint(crashpoint, crashtype);
0347af4e SK	310	if (err < 0)
	311	return err;
	312
	313	*off += count;
	314
	315	return count;
	316	}
2b271cb7	317	#endif
0347af4e SK	318
	319	/* Generic read callback that just prints out the available crash types */
	320	static ssize_t lkdtm_debugfs_read(struct file f, char __user user_buf,
	321	size_t count, loff_t *off)
	322	{
	323	char *buf;
	324	int i, n, out;
	325
	326	buf = (char *)__get_free_page(GFP_KERNEL);
086ff4b3 AC	327	if (buf == NULL)
086ff4b3 AC	328	return -ENOMEM;
0347af4e	329
87bf65bc	330	n = scnprintf(buf, PAGE_SIZE, "Available crash types:\n");
c479e3fd	331	for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
87bf65bc	332	n += scnprintf(buf + n, PAGE_SIZE - n, "%s\n",
c479e3fd KC	333	crashtypes[i].name);
c479e3fd KC	334	}
0347af4e SK	335	buf[n] = '\0';
	336
	337	out = simple_read_from_buffer(user_buf, count, off,
	338	buf, n);
	339	free_page((unsigned long) buf);
	340
	341	return out;
	342	}
	343
	344	static int lkdtm_debugfs_open(struct inode inode, struct file file)
	345	{
	346	return 0;
	347	}
	348
0347af4e SK	349	/* Special entry to just crash directly. Available without KPROBEs */
	350	static ssize_t direct_entry(struct file f, const char __user user_buf,
	351	size_t count, loff_t *off)
	352	{
75f98b7a	353	const struct crashtype *crashtype;
0347af4e SK	354	char *buf;
	355
	356	if (count >= PAGE_SIZE)
	357	return -EINVAL;
	358	if (count < 1)
	359	return -EINVAL;
	360
	361	buf = (char *)__get_free_page(GFP_KERNEL);
	362	if (!buf)
	363	return -ENOMEM;
	364	if (copy_from_user(buf, user_buf, count)) {
	365	free_page((unsigned long) buf);
	366	return -EFAULT;
	367	}
	368	/* NULL-terminate and remove enter */
	369	buf[count] = '\0';
	370	strim(buf);
	371
c479e3fd	372	crashtype = find_crashtype(buf);
0347af4e	373	free_page((unsigned long) buf);
c479e3fd	374	if (!crashtype)
0347af4e SK	375	return -EINVAL;
0347af4e SK	376
c479e3fd KC	377	pr_info("Performing direct entry %s\n", crashtype->name);
c479e3fd KC	378	lkdtm_do_action(crashtype);
0347af4e SK	379	*off += count;
	380
	381	return count;
	382	}
	383
0347af4e SK	384	static struct dentry *lkdtm_debugfs_root;
	385
	386	static int __init lkdtm_module_init(void)
	387	{
c479e3fd	388	struct crashpoint *crashpoint = NULL;
75f98b7a	389	const struct crashtype *crashtype = NULL;
0347af4e	390	int ret = -EINVAL;
0347af4e SK	391	int i;
0347af4e SK	392
c479e3fd KC	393	/* Neither or both of these need to be set */
	394	if ((cpoint_type \|\| cpoint_name) && !(cpoint_type && cpoint_name)) {
	395	pr_err("Need both cpoint_type and cpoint_name or neither\n");
	396	return -EINVAL;
	397	}
	398
	399	if (cpoint_type) {
	400	crashtype = find_crashtype(cpoint_type);
	401	if (!crashtype) {
	402	pr_err("Unknown crashtype '%s'\n", cpoint_type);
	403	return -EINVAL;
	404	}
	405	}
	406
	407	if (cpoint_name) {
	408	for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
	409	if (!strcmp(cpoint_name, crashpoints[i].name))
	410	crashpoint = &crashpoints[i];
	411	}
	412
	413	/* Refuse unknown crashpoints. */
	414	if (!crashpoint) {
	415	pr_err("Invalid crashpoint %s\n", cpoint_name);
	416	return -EINVAL;
	417	}
	418	}
	419
2b271cb7	420	#ifdef CONFIG_KPROBES
c479e3fd KC	421	/* Set crash count. */
c479e3fd KC	422	crash_count = cpoint_count;
2b271cb7	423	#endif
c479e3fd	424
a3dff71c	425	/* Handle test-specific initialization. */
00f496c4	426	lkdtm_bugs_init(&recur_count);
0d9eb29b	427	lkdtm_perms_init();
a3dff71c KC	428	lkdtm_usercopy_init();
a3dff71c KC	429
0347af4e SK	430	/* Register debugfs interface */
	431	lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
	432	if (!lkdtm_debugfs_root) {
feac6e21	433	pr_err("creating root dir failed\n");
0347af4e SK	434	return -ENODEV;
	435	}
	436
c479e3fd KC	437	/* Install debugfs trigger files. */
	438	for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
	439	struct crashpoint *cur = &crashpoints[i];
0347af4e SK	440	struct dentry *de;
	441
	442	de = debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root,
c479e3fd	443	cur, &cur->fops);
0347af4e	444	if (de == NULL) {
c479e3fd	445	pr_err("could not create crashpoint %s\n", cur->name);
0347af4e SK	446	goto out_err;
	447	}
	448	}
	449
c479e3fd KC	450	/* Install crashpoint if one was selected. */
	451	if (crashpoint) {
	452	ret = lkdtm_register_cpoint(crashpoint, crashtype);
0347af4e	453	if (ret < 0) {
c479e3fd	454	pr_info("Invalid crashpoint %s\n", crashpoint->name);
0347af4e SK	455	goto out_err;
0347af4e SK	456	}
feac6e21	457	pr_info("Crash point %s of type %s registered\n",
c479e3fd	458	crashpoint->name, cpoint_type);
0347af4e	459	} else {
feac6e21	460	pr_info("No crash points registered, enable through debugfs\n");
8bb31b9d AG	461	}
8bb31b9d AG	462
8bb31b9d	463	return 0;
0347af4e SK	464
	465	out_err:
	466	debugfs_remove_recursive(lkdtm_debugfs_root);
	467	return ret;
8bb31b9d AG	468	}
8bb31b9d AG	469
2118116e	470	static void __exit lkdtm_module_exit(void)
8bb31b9d	471	{
0347af4e SK	472	debugfs_remove_recursive(lkdtm_debugfs_root);
0347af4e SK	473
a3dff71c KC	474	/* Handle test-specific clean-up. */
a3dff71c KC	475	lkdtm_usercopy_exit();
aa981a66	476
31c5c870 KC	477	if (lkdtm_kprobe != NULL)
31c5c870 KC	478	unregister_kprobe(lkdtm_kprobe);
9ba60573	479
feac6e21	480	pr_info("Crash point unregistered\n");
8bb31b9d AG	481	}
	482
	483	module_init(lkdtm_module_init);
	484	module_exit(lkdtm_module_exit);
	485
	486	MODULE_LICENSE("GPL");
c479e3fd	487	MODULE_DESCRIPTION("Kernel crash testing module");