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20#include "lkdtm.h"
21#include <linux/fs.h>
22#include <linux/module.h>
23#include <linux/buffer_head.h>
24#include <linux/kprobes.h>
25#include <linux/list.h>
26#include <linux/init.h>
27#include <linux/slab.h>
28#include <linux/debugfs.h>
29#include <linux/utsname.h>
30
31#define DEFAULT_COUNT 10
32
33static int lkdtm_debugfs_open(struct inode *inode, struct file *file);
34static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
35 size_t count, loff_t *off);
36static ssize_t direct_entry(struct file *f, const char __user *user_buf,
37 size_t count, loff_t *off);
38
39#ifdef CONFIG_KPROBES
40static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs);
41static ssize_t lkdtm_debugfs_entry(struct file *f,
42 const char __user *user_buf,
43 size_t count, loff_t *off);
44# define CRASHPOINT_KPROBE(_symbol) \
45 .kprobe = { \
46 .symbol_name = (_symbol), \
47 .pre_handler = lkdtm_kprobe_handler, \
48 },
49# define CRASHPOINT_WRITE(_symbol) \
50 (_symbol) ? lkdtm_debugfs_entry : direct_entry
51#else
52# define CRASHPOINT_KPROBE(_symbol)
53# define CRASHPOINT_WRITE(_symbol) direct_entry
54#endif
55
56
57struct crashpoint {
58 const char *name;
59 const struct file_operations fops;
60 struct kprobe kprobe;
61};
62
63#define CRASHPOINT(_name, _symbol) \
64 { \
65 .name = _name, \
66 .fops = { \
67 .read = lkdtm_debugfs_read, \
68 .llseek = generic_file_llseek, \
69 .open = lkdtm_debugfs_open, \
70 .write = CRASHPOINT_WRITE(_symbol) \
71 }, \
72 CRASHPOINT_KPROBE(_symbol) \
73 }
74
75
76static struct crashpoint crashpoints[] = {
77 CRASHPOINT("DIRECT", NULL),
78#ifdef CONFIG_KPROBES
79 CRASHPOINT("INT_HARDWARE_ENTRY", "do_IRQ"),
80 CRASHPOINT("INT_HW_IRQ_EN", "handle_irq_event"),
81 CRASHPOINT("INT_TASKLET_ENTRY", "tasklet_action"),
82 CRASHPOINT("FS_DEVRW", "ll_rw_block"),
83 CRASHPOINT("MEM_SWAPOUT", "shrink_inactive_list"),
84 CRASHPOINT("TIMERADD", "hrtimer_start"),
85 CRASHPOINT("SCSI_QUEUE_RQ", "scsi_queue_rq"),
86#endif
87};
88
89
90
91struct crashtype {
92 const char *name;
93 void (*func)(void);
94};
95
96#define CRASHTYPE(_name) \
97 { \
98 .name = __stringify(_name), \
99 .func = lkdtm_ ## _name, \
100 }
101
102
103static const struct crashtype crashtypes[] = {
104 CRASHTYPE(PANIC),
105 CRASHTYPE(BUG),
106 CRASHTYPE(WARNING),
107 CRASHTYPE(WARNING_MESSAGE),
108 CRASHTYPE(EXCEPTION),
109 CRASHTYPE(LOOP),
110 CRASHTYPE(EXHAUST_STACK),
111 CRASHTYPE(CORRUPT_STACK),
112 CRASHTYPE(CORRUPT_STACK_STRONG),
113 CRASHTYPE(REPORT_STACK),
114 CRASHTYPE(CORRUPT_LIST_ADD),
115 CRASHTYPE(CORRUPT_LIST_DEL),
116 CRASHTYPE(STACK_GUARD_PAGE_LEADING),
117 CRASHTYPE(STACK_GUARD_PAGE_TRAILING),
118 CRASHTYPE(UNSET_SMEP),
119 CRASHTYPE(CORRUPT_PAC),
120 CRASHTYPE(UNALIGNED_LOAD_STORE_WRITE),
121 CRASHTYPE(SLAB_LINEAR_OVERFLOW),
122 CRASHTYPE(VMALLOC_LINEAR_OVERFLOW),
123 CRASHTYPE(WRITE_AFTER_FREE),
124 CRASHTYPE(READ_AFTER_FREE),
125 CRASHTYPE(WRITE_BUDDY_AFTER_FREE),
126 CRASHTYPE(READ_BUDDY_AFTER_FREE),
127 CRASHTYPE(SLAB_INIT_ON_ALLOC),
128 CRASHTYPE(BUDDY_INIT_ON_ALLOC),
129 CRASHTYPE(SLAB_FREE_DOUBLE),
130 CRASHTYPE(SLAB_FREE_CROSS),
131 CRASHTYPE(SLAB_FREE_PAGE),
132 CRASHTYPE(SOFTLOCKUP),
133 CRASHTYPE(HARDLOCKUP),
134 CRASHTYPE(SPINLOCKUP),
135 CRASHTYPE(HUNG_TASK),
136 CRASHTYPE(OVERFLOW_SIGNED),
137 CRASHTYPE(OVERFLOW_UNSIGNED),
138 CRASHTYPE(ARRAY_BOUNDS),
139 CRASHTYPE(EXEC_DATA),
140 CRASHTYPE(EXEC_STACK),
141 CRASHTYPE(EXEC_KMALLOC),
142 CRASHTYPE(EXEC_VMALLOC),
143 CRASHTYPE(EXEC_RODATA),
144 CRASHTYPE(EXEC_USERSPACE),
145 CRASHTYPE(EXEC_NULL),
146 CRASHTYPE(ACCESS_USERSPACE),
147 CRASHTYPE(ACCESS_NULL),
148 CRASHTYPE(WRITE_RO),
149 CRASHTYPE(WRITE_RO_AFTER_INIT),
150 CRASHTYPE(WRITE_KERN),
151 CRASHTYPE(REFCOUNT_INC_OVERFLOW),
152 CRASHTYPE(REFCOUNT_ADD_OVERFLOW),
153 CRASHTYPE(REFCOUNT_INC_NOT_ZERO_OVERFLOW),
154 CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_OVERFLOW),
155 CRASHTYPE(REFCOUNT_DEC_ZERO),
156 CRASHTYPE(REFCOUNT_DEC_NEGATIVE),
157 CRASHTYPE(REFCOUNT_DEC_AND_TEST_NEGATIVE),
158 CRASHTYPE(REFCOUNT_SUB_AND_TEST_NEGATIVE),
159 CRASHTYPE(REFCOUNT_INC_ZERO),
160 CRASHTYPE(REFCOUNT_ADD_ZERO),
161 CRASHTYPE(REFCOUNT_INC_SATURATED),
162 CRASHTYPE(REFCOUNT_DEC_SATURATED),
163 CRASHTYPE(REFCOUNT_ADD_SATURATED),
164 CRASHTYPE(REFCOUNT_INC_NOT_ZERO_SATURATED),
165 CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_SATURATED),
166 CRASHTYPE(REFCOUNT_DEC_AND_TEST_SATURATED),
167 CRASHTYPE(REFCOUNT_SUB_AND_TEST_SATURATED),
168 CRASHTYPE(REFCOUNT_TIMING),
169 CRASHTYPE(ATOMIC_TIMING),
170 CRASHTYPE(USERCOPY_HEAP_SIZE_TO),
171 CRASHTYPE(USERCOPY_HEAP_SIZE_FROM),
172 CRASHTYPE(USERCOPY_HEAP_WHITELIST_TO),
173 CRASHTYPE(USERCOPY_HEAP_WHITELIST_FROM),
174 CRASHTYPE(USERCOPY_STACK_FRAME_TO),
175 CRASHTYPE(USERCOPY_STACK_FRAME_FROM),
176 CRASHTYPE(USERCOPY_STACK_BEYOND),
177 CRASHTYPE(USERCOPY_KERNEL),
178 CRASHTYPE(STACKLEAK_ERASING),
179 CRASHTYPE(CFI_FORWARD_PROTO),
180 CRASHTYPE(FORTIFIED_OBJECT),
181 CRASHTYPE(FORTIFIED_SUBOBJECT),
182 CRASHTYPE(FORTIFIED_STRSCPY),
183 CRASHTYPE(DOUBLE_FAULT),
184#ifdef CONFIG_PPC_BOOK3S_64
185 CRASHTYPE(PPC_SLB_MULTIHIT),
186#endif
187};
188
189
190
191static struct kprobe *lkdtm_kprobe;
192static struct crashpoint *lkdtm_crashpoint;
193static const struct crashtype *lkdtm_crashtype;
194
195
196static int recur_count = -1;
197module_param(recur_count, int, 0644);
198MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test");
199
200static char* cpoint_name;
201module_param(cpoint_name, charp, 0444);
202MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
203
204static char* cpoint_type;
205module_param(cpoint_type, charp, 0444);
206MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
207 "hitting the crash point");
208
209static int cpoint_count = DEFAULT_COUNT;
210module_param(cpoint_count, int, 0644);
211MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
212 "crash point is to be hit to trigger action");
213
214
215char *lkdtm_kernel_info;
216
217
218static const struct crashtype *find_crashtype(const char *name)
219{
220 int i;
221
222 for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
223 if (!strcmp(name, crashtypes[i].name))
224 return &crashtypes[i];
225 }
226
227 return NULL;
228}
229
230
231
232
233
234static noinline void lkdtm_do_action(const struct crashtype *crashtype)
235{
236 if (WARN_ON(!crashtype || !crashtype->func))
237 return;
238 crashtype->func();
239}
240
241static int lkdtm_register_cpoint(struct crashpoint *crashpoint,
242 const struct crashtype *crashtype)
243{
244 int ret;
245
246
247 if (!crashpoint->kprobe.symbol_name) {
248 lkdtm_do_action(crashtype);
249 return 0;
250 }
251
252 if (lkdtm_kprobe != NULL)
253 unregister_kprobe(lkdtm_kprobe);
254
255 lkdtm_crashpoint = crashpoint;
256 lkdtm_crashtype = crashtype;
257 lkdtm_kprobe = &crashpoint->kprobe;
258 ret = register_kprobe(lkdtm_kprobe);
259 if (ret < 0) {
260 pr_info("Couldn't register kprobe %s\n",
261 crashpoint->kprobe.symbol_name);
262 lkdtm_kprobe = NULL;
263 lkdtm_crashpoint = NULL;
264 lkdtm_crashtype = NULL;
265 }
266
267 return ret;
268}
269
270#ifdef CONFIG_KPROBES
271
272static int crash_count = DEFAULT_COUNT;
273static DEFINE_SPINLOCK(crash_count_lock);
274
275
276static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs)
277{
278 unsigned long flags;
279 bool do_it = false;
280
281 if (WARN_ON(!lkdtm_crashpoint || !lkdtm_crashtype))
282 return 0;
283
284 spin_lock_irqsave(&crash_count_lock, flags);
285 crash_count--;
286 pr_info("Crash point %s of type %s hit, trigger in %d rounds\n",
287 lkdtm_crashpoint->name, lkdtm_crashtype->name, crash_count);
288
289 if (crash_count == 0) {
290 do_it = true;
291 crash_count = cpoint_count;
292 }
293 spin_unlock_irqrestore(&crash_count_lock, flags);
294
295 if (do_it)
296 lkdtm_do_action(lkdtm_crashtype);
297
298 return 0;
299}
300
301static ssize_t lkdtm_debugfs_entry(struct file *f,
302 const char __user *user_buf,
303 size_t count, loff_t *off)
304{
305 struct crashpoint *crashpoint = file_inode(f)->i_private;
306 const struct crashtype *crashtype = NULL;
307 char *buf;
308 int err;
309
310 if (count >= PAGE_SIZE)
311 return -EINVAL;
312
313 buf = (char *)__get_free_page(GFP_KERNEL);
314 if (!buf)
315 return -ENOMEM;
316 if (copy_from_user(buf, user_buf, count)) {
317 free_page((unsigned long) buf);
318 return -EFAULT;
319 }
320
321 buf[count] = '\0';
322 strim(buf);
323
324 crashtype = find_crashtype(buf);
325 free_page((unsigned long)buf);
326
327 if (!crashtype)
328 return -EINVAL;
329
330 err = lkdtm_register_cpoint(crashpoint, crashtype);
331 if (err < 0)
332 return err;
333
334 *off += count;
335
336 return count;
337}
338#endif
339
340
341static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
342 size_t count, loff_t *off)
343{
344 char *buf;
345 int i, n, out;
346
347 buf = (char *)__get_free_page(GFP_KERNEL);
348 if (buf == NULL)
349 return -ENOMEM;
350
351 n = scnprintf(buf, PAGE_SIZE, "Available crash types:\n");
352 for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
353 n += scnprintf(buf + n, PAGE_SIZE - n, "%s\n",
354 crashtypes[i].name);
355 }
356 buf[n] = '\0';
357
358 out = simple_read_from_buffer(user_buf, count, off,
359 buf, n);
360 free_page((unsigned long) buf);
361
362 return out;
363}
364
365static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
366{
367 return 0;
368}
369
370
371static ssize_t direct_entry(struct file *f, const char __user *user_buf,
372 size_t count, loff_t *off)
373{
374 const struct crashtype *crashtype;
375 char *buf;
376
377 if (count >= PAGE_SIZE)
378 return -EINVAL;
379 if (count < 1)
380 return -EINVAL;
381
382 buf = (char *)__get_free_page(GFP_KERNEL);
383 if (!buf)
384 return -ENOMEM;
385 if (copy_from_user(buf, user_buf, count)) {
386 free_page((unsigned long) buf);
387 return -EFAULT;
388 }
389
390 buf[count] = '\0';
391 strim(buf);
392
393 crashtype = find_crashtype(buf);
394 free_page((unsigned long) buf);
395 if (!crashtype)
396 return -EINVAL;
397
398 pr_info("Performing direct entry %s\n", crashtype->name);
399 lkdtm_do_action(crashtype);
400 *off += count;
401
402 return count;
403}
404
405#ifndef MODULE
406
407
408
409
410struct check_cmdline_args {
411 const char *param;
412 int value;
413};
414
415static int lkdtm_parse_one(char *param, char *val,
416 const char *unused, void *arg)
417{
418 struct check_cmdline_args *args = arg;
419
420
421 if (args->value != -ESRCH)
422 return 0;
423 if (strncmp(param, args->param, strlen(args->param)) == 0) {
424 bool bool_result;
425 int ret;
426
427 ret = kstrtobool(val, &bool_result);
428 if (ret == 0)
429 args->value = bool_result;
430 }
431 return 0;
432}
433
434int lkdtm_check_bool_cmdline(const char *param)
435{
436 char *command_line;
437 struct check_cmdline_args args = {
438 .param = param,
439 .value = -ESRCH,
440 };
441
442 command_line = kstrdup(saved_command_line, GFP_KERNEL);
443 if (!command_line)
444 return -ENOMEM;
445
446 parse_args("Setting sysctl args", command_line,
447 NULL, 0, -1, -1, &args, lkdtm_parse_one);
448
449 kfree(command_line);
450
451 return args.value;
452}
453#endif
454
455static struct dentry *lkdtm_debugfs_root;
456
457static int __init lkdtm_module_init(void)
458{
459 struct crashpoint *crashpoint = NULL;
460 const struct crashtype *crashtype = NULL;
461 int ret;
462 int i;
463
464
465 if ((cpoint_type || cpoint_name) && !(cpoint_type && cpoint_name)) {
466 pr_err("Need both cpoint_type and cpoint_name or neither\n");
467 return -EINVAL;
468 }
469
470 if (cpoint_type) {
471 crashtype = find_crashtype(cpoint_type);
472 if (!crashtype) {
473 pr_err("Unknown crashtype '%s'\n", cpoint_type);
474 return -EINVAL;
475 }
476 }
477
478 if (cpoint_name) {
479 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
480 if (!strcmp(cpoint_name, crashpoints[i].name))
481 crashpoint = &crashpoints[i];
482 }
483
484
485 if (!crashpoint) {
486 pr_err("Invalid crashpoint %s\n", cpoint_name);
487 return -EINVAL;
488 }
489 }
490
491#ifdef CONFIG_KPROBES
492
493 crash_count = cpoint_count;
494#endif
495
496
497 lkdtm_kernel_info = kasprintf(GFP_KERNEL, "kernel (%s %s)",
498 init_uts_ns.name.release,
499 init_uts_ns.name.machine);
500
501
502 lkdtm_bugs_init(&recur_count);
503 lkdtm_perms_init();
504 lkdtm_usercopy_init();
505 lkdtm_heap_init();
506
507
508 lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
509
510
511 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
512 struct crashpoint *cur = &crashpoints[i];
513
514 debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root, cur,
515 &cur->fops);
516 }
517
518
519 if (crashpoint) {
520 ret = lkdtm_register_cpoint(crashpoint, crashtype);
521 if (ret < 0) {
522 pr_info("Invalid crashpoint %s\n", crashpoint->name);
523 goto out_err;
524 }
525 pr_info("Crash point %s of type %s registered\n",
526 crashpoint->name, cpoint_type);
527 } else {
528 pr_info("No crash points registered, enable through debugfs\n");
529 }
530
531 return 0;
532
533out_err:
534 debugfs_remove_recursive(lkdtm_debugfs_root);
535 return ret;
536}
537
538static void __exit lkdtm_module_exit(void)
539{
540 debugfs_remove_recursive(lkdtm_debugfs_root);
541
542
543 lkdtm_heap_exit();
544 lkdtm_usercopy_exit();
545
546 if (lkdtm_kprobe != NULL)
547 unregister_kprobe(lkdtm_kprobe);
548
549 kfree(lkdtm_kernel_info);
550
551 pr_info("Crash point unregistered\n");
552}
553
554module_init(lkdtm_module_init);
555module_exit(lkdtm_module_exit);
556
557MODULE_LICENSE("GPL");
558MODULE_DESCRIPTION("Kernel crash testing module");
559
