1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
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.
8 *
9 * Copyright (C) IBM Corporation, 2006
10 *
11 * Author: Ankita Garg <ankita@in.ibm.com>
12 *
13 * It is adapted from the Linux Kernel Dump Test Tool by
14 * Fernando Luis Vazquez Cao <http://lkdtt.sourceforge.net>
15 *
16 * Debugfs support added by Simon Kagstrom <simon.kagstrom@netinsight.net>
17 *
18 * See Documentation/fault-injection/provoke-crashes.rst for instructions
19 */
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
33 static int lkdtm_debugfs_open(struct inode *inode, struct file *file);
34 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
35 size_t count, loff_t *off);
36 static ssize_t direct_entry(struct file *f, const char __user *user_buf,
37 size_t count, loff_t *off);
38
39 #ifdef CONFIG_KPROBES
40 static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs);
41 static 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 /* Crash points */
57 struct 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 /* Define the possible places where we can trigger a crash point. */
76 static 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 /* Crash types. */
91 struct 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 /* Define the possible types of crashes that can be triggered. */
103 static 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(REPORT_STACK_CANARY),
115 CRASHTYPE(CORRUPT_LIST_ADD),
116 CRASHTYPE(CORRUPT_LIST_DEL),
117 CRASHTYPE(STACK_GUARD_PAGE_LEADING),
118 CRASHTYPE(STACK_GUARD_PAGE_TRAILING),
119 CRASHTYPE(UNSET_SMEP),
120 CRASHTYPE(CORRUPT_PAC),
121 CRASHTYPE(UNALIGNED_LOAD_STORE_WRITE),
122 CRASHTYPE(SLAB_LINEAR_OVERFLOW),
123 CRASHTYPE(VMALLOC_LINEAR_OVERFLOW),
124 CRASHTYPE(WRITE_AFTER_FREE),
125 CRASHTYPE(READ_AFTER_FREE),
126 CRASHTYPE(WRITE_BUDDY_AFTER_FREE),
127 CRASHTYPE(READ_BUDDY_AFTER_FREE),
128 CRASHTYPE(SLAB_INIT_ON_ALLOC),
129 CRASHTYPE(BUDDY_INIT_ON_ALLOC),
130 CRASHTYPE(SLAB_FREE_DOUBLE),
131 CRASHTYPE(SLAB_FREE_CROSS),
132 CRASHTYPE(SLAB_FREE_PAGE),
133 CRASHTYPE(SOFTLOCKUP),
134 CRASHTYPE(HARDLOCKUP),
135 CRASHTYPE(SPINLOCKUP),
136 CRASHTYPE(HUNG_TASK),
137 CRASHTYPE(OVERFLOW_SIGNED),
138 CRASHTYPE(OVERFLOW_UNSIGNED),
139 CRASHTYPE(ARRAY_BOUNDS),
140 CRASHTYPE(EXEC_DATA),
141 CRASHTYPE(EXEC_STACK),
142 CRASHTYPE(EXEC_KMALLOC),
143 CRASHTYPE(EXEC_VMALLOC),
144 CRASHTYPE(EXEC_RODATA),
145 CRASHTYPE(EXEC_USERSPACE),
146 CRASHTYPE(EXEC_NULL),
147 CRASHTYPE(ACCESS_USERSPACE),
148 CRASHTYPE(ACCESS_NULL),
149 CRASHTYPE(WRITE_RO),
150 CRASHTYPE(WRITE_RO_AFTER_INIT),
151 CRASHTYPE(WRITE_KERN),
152 CRASHTYPE(REFCOUNT_INC_OVERFLOW),
153 CRASHTYPE(REFCOUNT_ADD_OVERFLOW),
154 CRASHTYPE(REFCOUNT_INC_NOT_ZERO_OVERFLOW),
155 CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_OVERFLOW),
156 CRASHTYPE(REFCOUNT_DEC_ZERO),
157 CRASHTYPE(REFCOUNT_DEC_NEGATIVE),
158 CRASHTYPE(REFCOUNT_DEC_AND_TEST_NEGATIVE),
159 CRASHTYPE(REFCOUNT_SUB_AND_TEST_NEGATIVE),
160 CRASHTYPE(REFCOUNT_INC_ZERO),
161 CRASHTYPE(REFCOUNT_ADD_ZERO),
162 CRASHTYPE(REFCOUNT_INC_SATURATED),
163 CRASHTYPE(REFCOUNT_DEC_SATURATED),
164 CRASHTYPE(REFCOUNT_ADD_SATURATED),
165 CRASHTYPE(REFCOUNT_INC_NOT_ZERO_SATURATED),
166 CRASHTYPE(REFCOUNT_ADD_NOT_ZERO_SATURATED),
167 CRASHTYPE(REFCOUNT_DEC_AND_TEST_SATURATED),
168 CRASHTYPE(REFCOUNT_SUB_AND_TEST_SATURATED),
169 CRASHTYPE(REFCOUNT_TIMING),
170 CRASHTYPE(ATOMIC_TIMING),
171 CRASHTYPE(USERCOPY_HEAP_SIZE_TO),
172 CRASHTYPE(USERCOPY_HEAP_SIZE_FROM),
173 CRASHTYPE(USERCOPY_HEAP_WHITELIST_TO),
174 CRASHTYPE(USERCOPY_HEAP_WHITELIST_FROM),
175 CRASHTYPE(USERCOPY_STACK_FRAME_TO),
176 CRASHTYPE(USERCOPY_STACK_FRAME_FROM),
177 CRASHTYPE(USERCOPY_STACK_BEYOND),
178 CRASHTYPE(USERCOPY_KERNEL),
179 CRASHTYPE(STACKLEAK_ERASING),
180 CRASHTYPE(CFI_FORWARD_PROTO),
181 CRASHTYPE(FORTIFIED_OBJECT),
182 CRASHTYPE(FORTIFIED_SUBOBJECT),
183 CRASHTYPE(FORTIFIED_STRSCPY),
184 CRASHTYPE(DOUBLE_FAULT),
185 #ifdef CONFIG_PPC_BOOK3S_64
186 CRASHTYPE(PPC_SLB_MULTIHIT),
187 #endif
188 };
189
190
191 /* Global kprobe entry and crashtype. */
192 static struct kprobe *lkdtm_kprobe;
193 static struct crashpoint *lkdtm_crashpoint;
194 static const struct crashtype *lkdtm_crashtype;
195
196 /* Module parameters */
197 static int recur_count = -1;
198 module_param(recur_count, int, 0644);
199 MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test");
200
201 static char* cpoint_name;
202 module_param(cpoint_name, charp, 0444);
203 MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
204
205 static char* cpoint_type;
206 module_param(cpoint_type, charp, 0444);
207 MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
208 "hitting the crash point");
209
210 static int cpoint_count = DEFAULT_COUNT;
211 module_param(cpoint_count, int, 0644);
212 MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
213 "crash point is to be hit to trigger action");
214
215 /* For test debug reporting. */
216 char *lkdtm_kernel_info;
217
218 /* Return the crashtype number or NULL if the name is invalid */
find_crashtype(const char * name)219 static const struct crashtype *find_crashtype(const char *name)
220 {
221 int i;
222
223 for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
224 if (!strcmp(name, crashtypes[i].name))
225 return &crashtypes[i];
226 }
227
228 return NULL;
229 }
230
231 /*
232 * This is forced noinline just so it distinctly shows up in the stackdump
233 * which makes validation of expected lkdtm crashes easier.
234 */
lkdtm_do_action(const struct crashtype * crashtype)235 static noinline void lkdtm_do_action(const struct crashtype *crashtype)
236 {
237 if (WARN_ON(!crashtype || !crashtype->func))
238 return;
239 crashtype->func();
240 }
241
lkdtm_register_cpoint(struct crashpoint * crashpoint,const struct crashtype * crashtype)242 static int lkdtm_register_cpoint(struct crashpoint *crashpoint,
243 const struct crashtype *crashtype)
244 {
245 int ret;
246
247 /* If this doesn't have a symbol, just call immediately. */
248 if (!crashpoint->kprobe.symbol_name) {
249 lkdtm_do_action(crashtype);
250 return 0;
251 }
252
253 if (lkdtm_kprobe != NULL)
254 unregister_kprobe(lkdtm_kprobe);
255
256 lkdtm_crashpoint = crashpoint;
257 lkdtm_crashtype = crashtype;
258 lkdtm_kprobe = &crashpoint->kprobe;
259 ret = register_kprobe(lkdtm_kprobe);
260 if (ret < 0) {
261 pr_info("Couldn't register kprobe %s\n",
262 crashpoint->kprobe.symbol_name);
263 lkdtm_kprobe = NULL;
264 lkdtm_crashpoint = NULL;
265 lkdtm_crashtype = NULL;
266 }
267
268 return ret;
269 }
270
271 #ifdef CONFIG_KPROBES
272 /* Global crash counter and spinlock. */
273 static int crash_count = DEFAULT_COUNT;
274 static DEFINE_SPINLOCK(crash_count_lock);
275
276 /* Called by kprobe entry points. */
lkdtm_kprobe_handler(struct kprobe * kp,struct pt_regs * regs)277 static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs)
278 {
279 unsigned long flags;
280 bool do_it = false;
281
282 if (WARN_ON(!lkdtm_crashpoint || !lkdtm_crashtype))
283 return 0;
284
285 spin_lock_irqsave(&crash_count_lock, flags);
286 crash_count--;
287 pr_info("Crash point %s of type %s hit, trigger in %d rounds\n",
288 lkdtm_crashpoint->name, lkdtm_crashtype->name, crash_count);
289
290 if (crash_count == 0) {
291 do_it = true;
292 crash_count = cpoint_count;
293 }
294 spin_unlock_irqrestore(&crash_count_lock, flags);
295
296 if (do_it)
297 lkdtm_do_action(lkdtm_crashtype);
298
299 return 0;
300 }
301
lkdtm_debugfs_entry(struct file * f,const char __user * user_buf,size_t count,loff_t * off)302 static ssize_t lkdtm_debugfs_entry(struct file *f,
303 const char __user *user_buf,
304 size_t count, loff_t *off)
305 {
306 struct crashpoint *crashpoint = file_inode(f)->i_private;
307 const struct crashtype *crashtype = NULL;
308 char *buf;
309 int err;
310
311 if (count >= PAGE_SIZE)
312 return -EINVAL;
313
314 buf = (char *)__get_free_page(GFP_KERNEL);
315 if (!buf)
316 return -ENOMEM;
317 if (copy_from_user(buf, user_buf, count)) {
318 free_page((unsigned long) buf);
319 return -EFAULT;
320 }
321 /* NULL-terminate and remove enter */
322 buf[count] = '\0';
323 strim(buf);
324
325 crashtype = find_crashtype(buf);
326 free_page((unsigned long)buf);
327
328 if (!crashtype)
329 return -EINVAL;
330
331 err = lkdtm_register_cpoint(crashpoint, crashtype);
332 if (err < 0)
333 return err;
334
335 *off += count;
336
337 return count;
338 }
339 #endif
340
341 /* Generic read callback that just prints out the available crash types */
lkdtm_debugfs_read(struct file * f,char __user * user_buf,size_t count,loff_t * off)342 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
343 size_t count, loff_t *off)
344 {
345 char *buf;
346 int i, n, out;
347
348 buf = (char *)__get_free_page(GFP_KERNEL);
349 if (buf == NULL)
350 return -ENOMEM;
351
352 n = scnprintf(buf, PAGE_SIZE, "Available crash types:\n");
353 for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
354 n += scnprintf(buf + n, PAGE_SIZE - n, "%s\n",
355 crashtypes[i].name);
356 }
357 buf[n] = '\0';
358
359 out = simple_read_from_buffer(user_buf, count, off,
360 buf, n);
361 free_page((unsigned long) buf);
362
363 return out;
364 }
365
lkdtm_debugfs_open(struct inode * inode,struct file * file)366 static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
367 {
368 return 0;
369 }
370
371 /* Special entry to just crash directly. Available without KPROBEs */
direct_entry(struct file * f,const char __user * user_buf,size_t count,loff_t * off)372 static ssize_t direct_entry(struct file *f, const char __user *user_buf,
373 size_t count, loff_t *off)
374 {
375 const struct crashtype *crashtype;
376 char *buf;
377
378 if (count >= PAGE_SIZE)
379 return -EINVAL;
380 if (count < 1)
381 return -EINVAL;
382
383 buf = (char *)__get_free_page(GFP_KERNEL);
384 if (!buf)
385 return -ENOMEM;
386 if (copy_from_user(buf, user_buf, count)) {
387 free_page((unsigned long) buf);
388 return -EFAULT;
389 }
390 /* NULL-terminate and remove enter */
391 buf[count] = '\0';
392 strim(buf);
393
394 crashtype = find_crashtype(buf);
395 free_page((unsigned long) buf);
396 if (!crashtype)
397 return -EINVAL;
398
399 pr_info("Performing direct entry %s\n", crashtype->name);
400 lkdtm_do_action(crashtype);
401 *off += count;
402
403 return count;
404 }
405
406 #ifndef MODULE
407 /*
408 * To avoid needing to export parse_args(), just don't use this code
409 * when LKDTM is built as a module.
410 */
411 struct check_cmdline_args {
412 const char *param;
413 int value;
414 };
415
lkdtm_parse_one(char * param,char * val,const char * unused,void * arg)416 static int lkdtm_parse_one(char *param, char *val,
417 const char *unused, void *arg)
418 {
419 struct check_cmdline_args *args = arg;
420
421 /* short circuit if we already found a value. */
422 if (args->value != -ESRCH)
423 return 0;
424 if (strncmp(param, args->param, strlen(args->param)) == 0) {
425 bool bool_result;
426 int ret;
427
428 ret = kstrtobool(val, &bool_result);
429 if (ret == 0)
430 args->value = bool_result;
431 }
432 return 0;
433 }
434
lkdtm_check_bool_cmdline(const char * param)435 int lkdtm_check_bool_cmdline(const char *param)
436 {
437 char *command_line;
438 struct check_cmdline_args args = {
439 .param = param,
440 .value = -ESRCH,
441 };
442
443 command_line = kstrdup(saved_command_line, GFP_KERNEL);
444 if (!command_line)
445 return -ENOMEM;
446
447 parse_args("Setting sysctl args", command_line,
448 NULL, 0, -1, -1, &args, lkdtm_parse_one);
449
450 kfree(command_line);
451
452 return args.value;
453 }
454 #endif
455
456 static struct dentry *lkdtm_debugfs_root;
457
lkdtm_module_init(void)458 static int __init lkdtm_module_init(void)
459 {
460 struct crashpoint *crashpoint = NULL;
461 const struct crashtype *crashtype = NULL;
462 int ret;
463 int i;
464
465 /* Neither or both of these need to be set */
466 if ((cpoint_type || cpoint_name) && !(cpoint_type && cpoint_name)) {
467 pr_err("Need both cpoint_type and cpoint_name or neither\n");
468 return -EINVAL;
469 }
470
471 if (cpoint_type) {
472 crashtype = find_crashtype(cpoint_type);
473 if (!crashtype) {
474 pr_err("Unknown crashtype '%s'\n", cpoint_type);
475 return -EINVAL;
476 }
477 }
478
479 if (cpoint_name) {
480 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
481 if (!strcmp(cpoint_name, crashpoints[i].name))
482 crashpoint = &crashpoints[i];
483 }
484
485 /* Refuse unknown crashpoints. */
486 if (!crashpoint) {
487 pr_err("Invalid crashpoint %s\n", cpoint_name);
488 return -EINVAL;
489 }
490 }
491
492 #ifdef CONFIG_KPROBES
493 /* Set crash count. */
494 crash_count = cpoint_count;
495 #endif
496
497 /* Common initialization. */
498 lkdtm_kernel_info = kasprintf(GFP_KERNEL, "kernel (%s %s)",
499 init_uts_ns.name.release,
500 init_uts_ns.name.machine);
501
502 /* Handle test-specific initialization. */
503 lkdtm_bugs_init(&recur_count);
504 lkdtm_perms_init();
505 lkdtm_usercopy_init();
506 lkdtm_heap_init();
507
508 /* Register debugfs interface */
509 lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
510
511 /* Install debugfs trigger files. */
512 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
513 struct crashpoint *cur = &crashpoints[i];
514
515 debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root, cur,
516 &cur->fops);
517 }
518
519 /* Install crashpoint if one was selected. */
520 if (crashpoint) {
521 ret = lkdtm_register_cpoint(crashpoint, crashtype);
522 if (ret < 0) {
523 pr_info("Invalid crashpoint %s\n", crashpoint->name);
524 goto out_err;
525 }
526 pr_info("Crash point %s of type %s registered\n",
527 crashpoint->name, cpoint_type);
528 } else {
529 pr_info("No crash points registered, enable through debugfs\n");
530 }
531
532 return 0;
533
534 out_err:
535 debugfs_remove_recursive(lkdtm_debugfs_root);
536 return ret;
537 }
538
lkdtm_module_exit(void)539 static void __exit lkdtm_module_exit(void)
540 {
541 debugfs_remove_recursive(lkdtm_debugfs_root);
542
543 /* Handle test-specific clean-up. */
544 lkdtm_heap_exit();
545 lkdtm_usercopy_exit();
546
547 if (lkdtm_kprobe != NULL)
548 unregister_kprobe(lkdtm_kprobe);
549
550 kfree(lkdtm_kernel_info);
551
552 pr_info("Crash point unregistered\n");
553 }
554
555 module_init(lkdtm_module_init);
556 module_exit(lkdtm_module_exit);
557
558 MODULE_LICENSE("GPL");
559 MODULE_DESCRIPTION("Kernel crash testing module");
560