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1 | /* |
2 | * Kernel Probes (KProbes) |
3 | * kernel/kprobes.c |
4 | * |
5 | * This program is free software; you can redistribute it and/or modify |
6 | * it under the terms of the GNU General Public License as published by |
7 | * the Free Software Foundation; either version 2 of the License, or |
8 | * (at your option) any later version. |
9 | * |
10 | * This program is distributed in the hope that it will be useful, |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
13 | * GNU General Public License for more details. |
14 | * |
15 | * You should have received a copy of the GNU General Public License |
16 | * along with this program; if not, write to the Free Software |
17 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
18 | * |
19 | * Copyright (C) IBM Corporation, 2002, 2004 |
20 | * |
21 | * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel |
22 | * Probes initial implementation (includes suggestions from |
23 | * Rusty Russell). |
24 | * 2004-Aug Updated by Prasanna S Panchamukhi <prasanna@in.ibm.com> with |
25 | * hlists and exceptions notifier as suggested by Andi Kleen. |
26 | * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes |
27 | * interface to access function arguments. |
28 | * 2004-Sep Prasanna S Panchamukhi <prasanna@in.ibm.com> Changed Kprobes |
29 | * exceptions notifier to be first on the priority list. |
30 | * 2005-May Hien Nguyen <hien@us.ibm.com>, Jim Keniston |
31 | * <jkenisto@us.ibm.com> and Prasanna S Panchamukhi |
32 | * <prasanna@in.ibm.com> added function-return probes. |
33 | */ |
34 | #include <linux/kprobes.h> |
35 | #include <linux/hash.h> |
36 | #include <linux/init.h> |
37 | #include <linux/slab.h> |
38 | #include <linux/stddef.h> |
39 | #include <linux/module.h> |
40 | #include <linux/moduleloader.h> |
41 | #include <linux/kallsyms.h> |
42 | #include <linux/freezer.h> |
43 | #include <linux/seq_file.h> |
44 | #include <linux/debugfs.h> |
45 | #include <linux/kdebug.h> |
46 | #include <linux/memory.h> |
47 | |
48 | #include <asm-generic/sections.h> |
49 | #include <asm/cacheflush.h> |
50 | #include <asm/errno.h> |
51 | #include <asm/uaccess.h> |
52 | |
53 | #define KPROBE_HASH_BITS 6 |
54 | #define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS) |
55 | |
56 | |
57 | /* |
58 | * Some oddball architectures like 64bit powerpc have function descriptors |
59 | * so this must be overridable. |
60 | */ |
61 | #ifndef kprobe_lookup_name |
62 | #define kprobe_lookup_name(name, addr) \ |
63 | addr = ((kprobe_opcode_t *)(kallsyms_lookup_name(name))) |
64 | #endif |
65 | |
66 | static int kprobes_initialized; |
67 | static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE]; |
68 | static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE]; |
69 | |
70 | /* NOTE: change this value only with kprobe_mutex held */ |
71 | static bool kprobes_all_disarmed; |
72 | |
73 | static DEFINE_MUTEX(kprobe_mutex); /* Protects kprobe_table */ |
74 | static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL; |
75 | static struct { |
76 | spinlock_t lock ____cacheline_aligned_in_smp; |
77 | } kretprobe_table_locks[KPROBE_TABLE_SIZE]; |
78 | |
79 | static spinlock_t *kretprobe_table_lock_ptr(unsigned long hash) |
80 | { |
81 | return &(kretprobe_table_locks[hash].lock); |
82 | } |
83 | |
84 | /* |
85 | * Normally, functions that we'd want to prohibit kprobes in, are marked |
86 | * __kprobes. But, there are cases where such functions already belong to |
87 | * a different section (__sched for preempt_schedule) |
88 | * |
89 | * For such cases, we now have a blacklist |
90 | */ |
91 | static struct kprobe_blackpoint kprobe_blacklist[] = { |
92 | {"preempt_schedule",}, |
93 | {NULL} /* Terminator */ |
94 | }; |
95 | |
96 | #ifdef __ARCH_WANT_KPROBES_INSN_SLOT |
97 | /* |
98 | * kprobe->ainsn.insn points to the copy of the instruction to be |
99 | * single-stepped. x86_64, POWER4 and above have no-exec support and |
100 | * stepping on the instruction on a vmalloced/kmalloced/data page |
101 | * is a recipe for disaster |
102 | */ |
103 | #define INSNS_PER_PAGE (PAGE_SIZE/(MAX_INSN_SIZE * sizeof(kprobe_opcode_t))) |
104 | |
105 | struct kprobe_insn_page { |
106 | struct hlist_node hlist; |
107 | kprobe_opcode_t *insns; /* Page of instruction slots */ |
108 | char slot_used[INSNS_PER_PAGE]; |
109 | int nused; |
110 | int ngarbage; |
111 | }; |
112 | |
113 | enum kprobe_slot_state { |
114 | SLOT_CLEAN = 0, |
115 | SLOT_DIRTY = 1, |
116 | SLOT_USED = 2, |
117 | }; |
118 | |
119 | static DEFINE_MUTEX(kprobe_insn_mutex); /* Protects kprobe_insn_pages */ |
120 | static struct hlist_head kprobe_insn_pages; |
121 | static int kprobe_garbage_slots; |
122 | static int collect_garbage_slots(void); |
123 | |
124 | static int __kprobes check_safety(void) |
125 | { |
126 | int ret = 0; |
127 | #if defined(CONFIG_PREEMPT) && defined(CONFIG_FREEZER) |
128 | ret = freeze_processes(); |
129 | if (ret == 0) { |
130 | struct task_struct *p, *q; |
131 | do_each_thread(p, q) { |
132 | if (p != current && p->state == TASK_RUNNING && |
133 | p->pid != 0) { |
134 | printk("Check failed: %s is running\n",p->comm); |
135 | ret = -1; |
136 | goto loop_end; |
137 | } |
138 | } while_each_thread(p, q); |
139 | } |
140 | loop_end: |
141 | thaw_processes(); |
142 | #else |
143 | synchronize_sched(); |
144 | #endif |
145 | return ret; |
146 | } |
147 | |
148 | /** |
149 | * __get_insn_slot() - Find a slot on an executable page for an instruction. |
150 | * We allocate an executable page if there's no room on existing ones. |
151 | */ |
152 | static kprobe_opcode_t __kprobes *__get_insn_slot(void) |
153 | { |
154 | struct kprobe_insn_page *kip; |
155 | struct hlist_node *pos; |
156 | |
157 | retry: |
158 | hlist_for_each_entry(kip, pos, &kprobe_insn_pages, hlist) { |
159 | if (kip->nused < INSNS_PER_PAGE) { |
160 | int i; |
161 | for (i = 0; i < INSNS_PER_PAGE; i++) { |
162 | if (kip->slot_used[i] == SLOT_CLEAN) { |
163 | kip->slot_used[i] = SLOT_USED; |
164 | kip->nused++; |
165 | return kip->insns + (i * MAX_INSN_SIZE); |
166 | } |
167 | } |
168 | /* Surprise! No unused slots. Fix kip->nused. */ |
169 | kip->nused = INSNS_PER_PAGE; |
170 | } |
171 | } |
172 | |
173 | /* If there are any garbage slots, collect it and try again. */ |
174 | if (kprobe_garbage_slots && collect_garbage_slots() == 0) { |
175 | goto retry; |
176 | } |
177 | /* All out of space. Need to allocate a new page. Use slot 0. */ |
178 | kip = kmalloc(sizeof(struct kprobe_insn_page), GFP_KERNEL); |
179 | if (!kip) |
180 | return NULL; |
181 | |
182 | /* |
183 | * Use module_alloc so this page is within +/- 2GB of where the |
184 | * kernel image and loaded module images reside. This is required |
185 | * so x86_64 can correctly handle the %rip-relative fixups. |
186 | */ |
187 | kip->insns = module_alloc(PAGE_SIZE); |
188 | if (!kip->insns) { |
189 | kfree(kip); |
190 | return NULL; |
191 | } |
192 | INIT_HLIST_NODE(&kip->hlist); |
193 | hlist_add_head(&kip->hlist, &kprobe_insn_pages); |
194 | memset(kip->slot_used, SLOT_CLEAN, INSNS_PER_PAGE); |
195 | kip->slot_used[0] = SLOT_USED; |
196 | kip->nused = 1; |
197 | kip->ngarbage = 0; |
198 | return kip->insns; |
199 | } |
200 | |
201 | kprobe_opcode_t __kprobes *get_insn_slot(void) |
202 | { |
203 | kprobe_opcode_t *ret; |
204 | mutex_lock(&kprobe_insn_mutex); |
205 | ret = __get_insn_slot(); |
206 | mutex_unlock(&kprobe_insn_mutex); |
207 | return ret; |
208 | } |
209 | |
210 | /* Return 1 if all garbages are collected, otherwise 0. */ |
211 | static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx) |
212 | { |
213 | kip->slot_used[idx] = SLOT_CLEAN; |
214 | kip->nused--; |
215 | if (kip->nused == 0) { |
216 | /* |
217 | * Page is no longer in use. Free it unless |
218 | * it's the last one. We keep the last one |
219 | * so as not to have to set it up again the |
220 | * next time somebody inserts a probe. |
221 | */ |
222 | hlist_del(&kip->hlist); |
223 | if (hlist_empty(&kprobe_insn_pages)) { |
224 | INIT_HLIST_NODE(&kip->hlist); |
225 | hlist_add_head(&kip->hlist, |
226 | &kprobe_insn_pages); |
227 | } else { |
228 | module_free(NULL, kip->insns); |
229 | kfree(kip); |
230 | } |
231 | return 1; |
232 | } |
233 | return 0; |
234 | } |
235 | |
236 | static int __kprobes collect_garbage_slots(void) |
237 | { |
238 | struct kprobe_insn_page *kip; |
239 | struct hlist_node *pos, *next; |
240 | |
241 | /* Ensure no-one is preepmted on the garbages */ |
242 | if (check_safety()) |
243 | return -EAGAIN; |
244 | |
245 | hlist_for_each_entry_safe(kip, pos, next, &kprobe_insn_pages, hlist) { |
246 | int i; |
247 | if (kip->ngarbage == 0) |
248 | continue; |
249 | kip->ngarbage = 0; /* we will collect all garbages */ |
250 | for (i = 0; i < INSNS_PER_PAGE; i++) { |
251 | if (kip->slot_used[i] == SLOT_DIRTY && |
252 | collect_one_slot(kip, i)) |
253 | break; |
254 | } |
255 | } |
256 | kprobe_garbage_slots = 0; |
257 | return 0; |
258 | } |
259 | |
260 | void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty) |
261 | { |
262 | struct kprobe_insn_page *kip; |
263 | struct hlist_node *pos; |
264 | |
265 | mutex_lock(&kprobe_insn_mutex); |
266 | hlist_for_each_entry(kip, pos, &kprobe_insn_pages, hlist) { |
267 | if (kip->insns <= slot && |
268 | slot < kip->insns + (INSNS_PER_PAGE * MAX_INSN_SIZE)) { |
269 | int i = (slot - kip->insns) / MAX_INSN_SIZE; |
270 | if (dirty) { |
271 | kip->slot_used[i] = SLOT_DIRTY; |
272 | kip->ngarbage++; |
273 | } else { |
274 | collect_one_slot(kip, i); |
275 | } |
276 | break; |
277 | } |
278 | } |
279 | |
280 | if (dirty && ++kprobe_garbage_slots > INSNS_PER_PAGE) |
281 | collect_garbage_slots(); |
282 | |
283 | mutex_unlock(&kprobe_insn_mutex); |
284 | } |
285 | #endif |
286 | |
287 | /* We have preemption disabled.. so it is safe to use __ versions */ |
288 | static inline void set_kprobe_instance(struct kprobe *kp) |
289 | { |
290 | __get_cpu_var(kprobe_instance) = kp; |
291 | } |
292 | |
293 | static inline void reset_kprobe_instance(void) |
294 | { |
295 | __get_cpu_var(kprobe_instance) = NULL; |
296 | } |
297 | |
298 | /* |
299 | * This routine is called either: |
300 | * - under the kprobe_mutex - during kprobe_[un]register() |
301 | * OR |
302 | * - with preemption disabled - from arch/xxx/kernel/kprobes.c |
303 | */ |
304 | struct kprobe __kprobes *get_kprobe(void *addr) |
305 | { |
306 | struct hlist_head *head; |
307 | struct hlist_node *node; |
308 | struct kprobe *p; |
309 | |
310 | head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)]; |
311 | hlist_for_each_entry_rcu(p, node, head, hlist) { |
312 | if (p->addr == addr) |
313 | return p; |
314 | } |
315 | return NULL; |
316 | } |
317 | |
318 | /* Arm a kprobe with text_mutex */ |
319 | static void __kprobes arm_kprobe(struct kprobe *kp) |
320 | { |
321 | mutex_lock(&text_mutex); |
322 | arch_arm_kprobe(kp); |
323 | mutex_unlock(&text_mutex); |
324 | } |
325 | |
326 | /* Disarm a kprobe with text_mutex */ |
327 | static void __kprobes disarm_kprobe(struct kprobe *kp) |
328 | { |
329 | mutex_lock(&text_mutex); |
330 | arch_disarm_kprobe(kp); |
331 | mutex_unlock(&text_mutex); |
332 | } |
333 | |
334 | /* |
335 | * Aggregate handlers for multiple kprobes support - these handlers |
336 | * take care of invoking the individual kprobe handlers on p->list |
337 | */ |
338 | static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs) |
339 | { |
340 | struct kprobe *kp; |
341 | |
342 | list_for_each_entry_rcu(kp, &p->list, list) { |
343 | if (kp->pre_handler && likely(!kprobe_disabled(kp))) { |
344 | set_kprobe_instance(kp); |
345 | if (kp->pre_handler(kp, regs)) |
346 | return 1; |
347 | } |
348 | reset_kprobe_instance(); |
349 | } |
350 | return 0; |
351 | } |
352 | |
353 | static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs, |
354 | unsigned long flags) |
355 | { |
356 | struct kprobe *kp; |
357 | |
358 | list_for_each_entry_rcu(kp, &p->list, list) { |
359 | if (kp->post_handler && likely(!kprobe_disabled(kp))) { |
360 | set_kprobe_instance(kp); |
361 | kp->post_handler(kp, regs, flags); |
362 | reset_kprobe_instance(); |
363 | } |
364 | } |
365 | } |
366 | |
367 | static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs, |
368 | int trapnr) |
369 | { |
370 | struct kprobe *cur = __get_cpu_var(kprobe_instance); |
371 | |
372 | /* |
373 | * if we faulted "during" the execution of a user specified |
374 | * probe handler, invoke just that probe's fault handler |
375 | */ |
376 | if (cur && cur->fault_handler) { |
377 | if (cur->fault_handler(cur, regs, trapnr)) |
378 | return 1; |
379 | } |
380 | return 0; |
381 | } |
382 | |
383 | static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs) |
384 | { |
385 | struct kprobe *cur = __get_cpu_var(kprobe_instance); |
386 | int ret = 0; |
387 | |
388 | if (cur && cur->break_handler) { |
389 | if (cur->break_handler(cur, regs)) |
390 | ret = 1; |
391 | } |
392 | reset_kprobe_instance(); |
393 | return ret; |
394 | } |
395 | |
396 | /* Walks the list and increments nmissed count for multiprobe case */ |
397 | void __kprobes kprobes_inc_nmissed_count(struct kprobe *p) |
398 | { |
399 | struct kprobe *kp; |
400 | if (p->pre_handler != aggr_pre_handler) { |
401 | p->nmissed++; |
402 | } else { |
403 | list_for_each_entry_rcu(kp, &p->list, list) |
404 | kp->nmissed++; |
405 | } |
406 | return; |
407 | } |
408 | |
409 | void __kprobes recycle_rp_inst(struct kretprobe_instance *ri, |
410 | struct hlist_head *head) |
411 | { |
412 | struct kretprobe *rp = ri->rp; |
413 | |
414 | /* remove rp inst off the rprobe_inst_table */ |
415 | hlist_del(&ri->hlist); |
416 | INIT_HLIST_NODE(&ri->hlist); |
417 | if (likely(rp)) { |
418 | spin_lock(&rp->lock); |
419 | hlist_add_head(&ri->hlist, &rp->free_instances); |
420 | spin_unlock(&rp->lock); |
421 | } else |
422 | /* Unregistering */ |
423 | hlist_add_head(&ri->hlist, head); |
424 | } |
425 | |
426 | void __kprobes kretprobe_hash_lock(struct task_struct *tsk, |
427 | struct hlist_head **head, unsigned long *flags) |
428 | { |
429 | unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS); |
430 | spinlock_t *hlist_lock; |
431 | |
432 | *head = &kretprobe_inst_table[hash]; |
433 | hlist_lock = kretprobe_table_lock_ptr(hash); |
434 | spin_lock_irqsave(hlist_lock, *flags); |
435 | } |
436 | |
437 | static void __kprobes kretprobe_table_lock(unsigned long hash, |
438 | unsigned long *flags) |
439 | { |
440 | spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash); |
441 | spin_lock_irqsave(hlist_lock, *flags); |
442 | } |
443 | |
444 | void __kprobes kretprobe_hash_unlock(struct task_struct *tsk, |
445 | unsigned long *flags) |
446 | { |
447 | unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS); |
448 | spinlock_t *hlist_lock; |
449 | |
450 | hlist_lock = kretprobe_table_lock_ptr(hash); |
451 | spin_unlock_irqrestore(hlist_lock, *flags); |
452 | } |
453 | |
454 | void __kprobes kretprobe_table_unlock(unsigned long hash, unsigned long *flags) |
455 | { |
456 | spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash); |
457 | spin_unlock_irqrestore(hlist_lock, *flags); |
458 | } |
459 | |
460 | /* |
461 | * This function is called from finish_task_switch when task tk becomes dead, |
462 | * so that we can recycle any function-return probe instances associated |
463 | * with this task. These left over instances represent probed functions |
464 | * that have been called but will never return. |
465 | */ |
466 | void __kprobes kprobe_flush_task(struct task_struct *tk) |
467 | { |
468 | struct kretprobe_instance *ri; |
469 | struct hlist_head *head, empty_rp; |
470 | struct hlist_node *node, *tmp; |
471 | unsigned long hash, flags = 0; |
472 | |
473 | if (unlikely(!kprobes_initialized)) |
474 | /* Early boot. kretprobe_table_locks not yet initialized. */ |
475 | return; |
476 | |
477 | hash = hash_ptr(tk, KPROBE_HASH_BITS); |
478 | head = &kretprobe_inst_table[hash]; |
479 | kretprobe_table_lock(hash, &flags); |
480 | hlist_for_each_entry_safe(ri, node, tmp, head, hlist) { |
481 | if (ri->task == tk) |
482 | recycle_rp_inst(ri, &empty_rp); |
483 | } |
484 | kretprobe_table_unlock(hash, &flags); |
485 | INIT_HLIST_HEAD(&empty_rp); |
486 | hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) { |
487 | hlist_del(&ri->hlist); |
488 | kfree(ri); |
489 | } |
490 | } |
491 | |
492 | static inline void free_rp_inst(struct kretprobe *rp) |
493 | { |
494 | struct kretprobe_instance *ri; |
495 | struct hlist_node *pos, *next; |
496 | |
497 | hlist_for_each_entry_safe(ri, pos, next, &rp->free_instances, hlist) { |
498 | hlist_del(&ri->hlist); |
499 | kfree(ri); |
500 | } |
501 | } |
502 | |
503 | static void __kprobes cleanup_rp_inst(struct kretprobe *rp) |
504 | { |
505 | unsigned long flags, hash; |
506 | struct kretprobe_instance *ri; |
507 | struct hlist_node *pos, *next; |
508 | struct hlist_head *head; |
509 | |
510 | /* No race here */ |
511 | for (hash = 0; hash < KPROBE_TABLE_SIZE; hash++) { |
512 | kretprobe_table_lock(hash, &flags); |
513 | head = &kretprobe_inst_table[hash]; |
514 | hlist_for_each_entry_safe(ri, pos, next, head, hlist) { |
515 | if (ri->rp == rp) |
516 | ri->rp = NULL; |
517 | } |
518 | kretprobe_table_unlock(hash, &flags); |
519 | } |
520 | free_rp_inst(rp); |
521 | } |
522 | |
523 | /* |
524 | * Keep all fields in the kprobe consistent |
525 | */ |
526 | static inline void copy_kprobe(struct kprobe *old_p, struct kprobe *p) |
527 | { |
528 | memcpy(&p->opcode, &old_p->opcode, sizeof(kprobe_opcode_t)); |
529 | memcpy(&p->ainsn, &old_p->ainsn, sizeof(struct arch_specific_insn)); |
530 | } |
531 | |
532 | /* |
533 | * Add the new probe to ap->list. Fail if this is the |
534 | * second jprobe at the address - two jprobes can't coexist |
535 | */ |
536 | static int __kprobes add_new_kprobe(struct kprobe *ap, struct kprobe *p) |
537 | { |
538 | BUG_ON(kprobe_gone(ap) || kprobe_gone(p)); |
539 | if (p->break_handler) { |
540 | if (ap->break_handler) |
541 | return -EEXIST; |
542 | list_add_tail_rcu(&p->list, &ap->list); |
543 | ap->break_handler = aggr_break_handler; |
544 | } else |
545 | list_add_rcu(&p->list, &ap->list); |
546 | if (p->post_handler && !ap->post_handler) |
547 | ap->post_handler = aggr_post_handler; |
548 | |
549 | if (kprobe_disabled(ap) && !kprobe_disabled(p)) { |
550 | ap->flags &= ~KPROBE_FLAG_DISABLED; |
551 | if (!kprobes_all_disarmed) |
552 | /* Arm the breakpoint again. */ |
553 | arm_kprobe(ap); |
554 | } |
555 | return 0; |
556 | } |
557 | |
558 | /* |
559 | * Fill in the required fields of the "manager kprobe". Replace the |
560 | * earlier kprobe in the hlist with the manager kprobe |
561 | */ |
562 | static inline void add_aggr_kprobe(struct kprobe *ap, struct kprobe *p) |
563 | { |
564 | copy_kprobe(p, ap); |
565 | flush_insn_slot(ap); |
566 | ap->addr = p->addr; |
567 | ap->flags = p->flags; |
568 | ap->pre_handler = aggr_pre_handler; |
569 | ap->fault_handler = aggr_fault_handler; |
570 | /* We don't care the kprobe which has gone. */ |
571 | if (p->post_handler && !kprobe_gone(p)) |
572 | ap->post_handler = aggr_post_handler; |
573 | if (p->break_handler && !kprobe_gone(p)) |
574 | ap->break_handler = aggr_break_handler; |
575 | |
576 | INIT_LIST_HEAD(&ap->list); |
577 | list_add_rcu(&p->list, &ap->list); |
578 | |
579 | hlist_replace_rcu(&p->hlist, &ap->hlist); |
580 | } |
581 | |
582 | /* |
583 | * This is the second or subsequent kprobe at the address - handle |
584 | * the intricacies |
585 | */ |
586 | static int __kprobes register_aggr_kprobe(struct kprobe *old_p, |
587 | struct kprobe *p) |
588 | { |
589 | int ret = 0; |
590 | struct kprobe *ap = old_p; |
591 | |
592 | if (old_p->pre_handler != aggr_pre_handler) { |
593 | /* If old_p is not an aggr_probe, create new aggr_kprobe. */ |
594 | ap = kzalloc(sizeof(struct kprobe), GFP_KERNEL); |
595 | if (!ap) |
596 | return -ENOMEM; |
597 | add_aggr_kprobe(ap, old_p); |
598 | } |
599 | |
600 | if (kprobe_gone(ap)) { |
601 | /* |
602 | * Attempting to insert new probe at the same location that |
603 | * had a probe in the module vaddr area which already |
604 | * freed. So, the instruction slot has already been |
605 | * released. We need a new slot for the new probe. |
606 | */ |
607 | ret = arch_prepare_kprobe(ap); |
608 | if (ret) |
609 | /* |
610 | * Even if fail to allocate new slot, don't need to |
611 | * free aggr_probe. It will be used next time, or |
612 | * freed by unregister_kprobe. |
613 | */ |
614 | return ret; |
615 | |
616 | /* |
617 | * Clear gone flag to prevent allocating new slot again, and |
618 | * set disabled flag because it is not armed yet. |
619 | */ |
620 | ap->flags = (ap->flags & ~KPROBE_FLAG_GONE) |
621 | | KPROBE_FLAG_DISABLED; |
622 | } |
623 | |
624 | copy_kprobe(ap, p); |
625 | return add_new_kprobe(ap, p); |
626 | } |
627 | |
628 | /* Try to disable aggr_kprobe, and return 1 if succeeded.*/ |
629 | static int __kprobes try_to_disable_aggr_kprobe(struct kprobe *p) |
630 | { |
631 | struct kprobe *kp; |
632 | |
633 | list_for_each_entry_rcu(kp, &p->list, list) { |
634 | if (!kprobe_disabled(kp)) |
635 | /* |
636 | * There is an active probe on the list. |
637 | * We can't disable aggr_kprobe. |
638 | */ |
639 | return 0; |
640 | } |
641 | p->flags |= KPROBE_FLAG_DISABLED; |
642 | return 1; |
643 | } |
644 | |
645 | static int __kprobes in_kprobes_functions(unsigned long addr) |
646 | { |
647 | struct kprobe_blackpoint *kb; |
648 | |
649 | if (addr >= (unsigned long)__kprobes_text_start && |
650 | addr < (unsigned long)__kprobes_text_end) |
651 | return -EINVAL; |
652 | /* |
653 | * If there exists a kprobe_blacklist, verify and |
654 | * fail any probe registration in the prohibited area |
655 | */ |
656 | for (kb = kprobe_blacklist; kb->name != NULL; kb++) { |
657 | if (kb->start_addr) { |
658 | if (addr >= kb->start_addr && |
659 | addr < (kb->start_addr + kb->range)) |
660 | return -EINVAL; |
661 | } |
662 | } |
663 | return 0; |
664 | } |
665 | |
666 | /* |
667 | * If we have a symbol_name argument, look it up and add the offset field |
668 | * to it. This way, we can specify a relative address to a symbol. |
669 | */ |
670 | static kprobe_opcode_t __kprobes *kprobe_addr(struct kprobe *p) |
671 | { |
672 | kprobe_opcode_t *addr = p->addr; |
673 | if (p->symbol_name) { |
674 | if (addr) |
675 | return NULL; |
676 | kprobe_lookup_name(p->symbol_name, addr); |
677 | } |
678 | |
679 | if (!addr) |
680 | return NULL; |
681 | return (kprobe_opcode_t *)(((char *)addr) + p->offset); |
682 | } |
683 | |
684 | int __kprobes register_kprobe(struct kprobe *p) |
685 | { |
686 | int ret = 0; |
687 | struct kprobe *old_p; |
688 | struct module *probed_mod; |
689 | kprobe_opcode_t *addr; |
690 | |
691 | addr = kprobe_addr(p); |
692 | if (!addr) |
693 | return -EINVAL; |
694 | p->addr = addr; |
695 | |
696 | preempt_disable(); |
697 | if (!kernel_text_address((unsigned long) p->addr) || |
698 | in_kprobes_functions((unsigned long) p->addr)) { |
699 | preempt_enable(); |
700 | return -EINVAL; |
701 | } |
702 | |
703 | /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */ |
704 | p->flags &= KPROBE_FLAG_DISABLED; |
705 | |
706 | /* |
707 | * Check if are we probing a module. |
708 | */ |
709 | probed_mod = __module_text_address((unsigned long) p->addr); |
710 | if (probed_mod) { |
711 | /* |
712 | * We must hold a refcount of the probed module while updating |
713 | * its code to prohibit unexpected unloading. |
714 | */ |
715 | if (unlikely(!try_module_get(probed_mod))) { |
716 | preempt_enable(); |
717 | return -EINVAL; |
718 | } |
719 | /* |
720 | * If the module freed .init.text, we couldn't insert |
721 | * kprobes in there. |
722 | */ |
723 | if (within_module_init((unsigned long)p->addr, probed_mod) && |
724 | probed_mod->state != MODULE_STATE_COMING) { |
725 | module_put(probed_mod); |
726 | preempt_enable(); |
727 | return -EINVAL; |
728 | } |
729 | } |
730 | preempt_enable(); |
731 | |
732 | p->nmissed = 0; |
733 | INIT_LIST_HEAD(&p->list); |
734 | mutex_lock(&kprobe_mutex); |
735 | old_p = get_kprobe(p->addr); |
736 | if (old_p) { |
737 | ret = register_aggr_kprobe(old_p, p); |
738 | goto out; |
739 | } |
740 | |
741 | mutex_lock(&text_mutex); |
742 | ret = arch_prepare_kprobe(p); |
743 | if (ret) |
744 | goto out_unlock_text; |
745 | |
746 | INIT_HLIST_NODE(&p->hlist); |
747 | hlist_add_head_rcu(&p->hlist, |
748 | &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]); |
749 | |
750 | if (!kprobes_all_disarmed && !kprobe_disabled(p)) |
751 | arch_arm_kprobe(p); |
752 | |
753 | out_unlock_text: |
754 | mutex_unlock(&text_mutex); |
755 | out: |
756 | mutex_unlock(&kprobe_mutex); |
757 | |
758 | if (probed_mod) |
759 | module_put(probed_mod); |
760 | |
761 | return ret; |
762 | } |
763 | EXPORT_SYMBOL_GPL(register_kprobe); |
764 | |
765 | /* Check passed kprobe is valid and return kprobe in kprobe_table. */ |
766 | static struct kprobe * __kprobes __get_valid_kprobe(struct kprobe *p) |
767 | { |
768 | struct kprobe *old_p, *list_p; |
769 | |
770 | old_p = get_kprobe(p->addr); |
771 | if (unlikely(!old_p)) |
772 | return NULL; |
773 | |
774 | if (p != old_p) { |
775 | list_for_each_entry_rcu(list_p, &old_p->list, list) |
776 | if (list_p == p) |
777 | /* kprobe p is a valid probe */ |
778 | goto valid; |
779 | return NULL; |
780 | } |
781 | valid: |
782 | return old_p; |
783 | } |
784 | |
785 | /* |
786 | * Unregister a kprobe without a scheduler synchronization. |
787 | */ |
788 | static int __kprobes __unregister_kprobe_top(struct kprobe *p) |
789 | { |
790 | struct kprobe *old_p, *list_p; |
791 | |
792 | old_p = __get_valid_kprobe(p); |
793 | if (old_p == NULL) |
794 | return -EINVAL; |
795 | |
796 | if (old_p == p || |
797 | (old_p->pre_handler == aggr_pre_handler && |
798 | list_is_singular(&old_p->list))) { |
799 | /* |
800 | * Only probe on the hash list. Disarm only if kprobes are |
801 | * enabled and not gone - otherwise, the breakpoint would |
802 | * already have been removed. We save on flushing icache. |
803 | */ |
804 | if (!kprobes_all_disarmed && !kprobe_disabled(old_p)) |
805 | disarm_kprobe(p); |
806 | hlist_del_rcu(&old_p->hlist); |
807 | } else { |
808 | if (p->break_handler && !kprobe_gone(p)) |
809 | old_p->break_handler = NULL; |
810 | if (p->post_handler && !kprobe_gone(p)) { |
811 | list_for_each_entry_rcu(list_p, &old_p->list, list) { |
812 | if ((list_p != p) && (list_p->post_handler)) |
813 | goto noclean; |
814 | } |
815 | old_p->post_handler = NULL; |
816 | } |
817 | noclean: |
818 | list_del_rcu(&p->list); |
819 | if (!kprobe_disabled(old_p)) { |
820 | try_to_disable_aggr_kprobe(old_p); |
821 | if (!kprobes_all_disarmed && kprobe_disabled(old_p)) |
822 | disarm_kprobe(old_p); |
823 | } |
824 | } |
825 | return 0; |
826 | } |
827 | |
828 | static void __kprobes __unregister_kprobe_bottom(struct kprobe *p) |
829 | { |
830 | struct kprobe *old_p; |
831 | |
832 | if (list_empty(&p->list)) |
833 | arch_remove_kprobe(p); |
834 | else if (list_is_singular(&p->list)) { |
835 | /* "p" is the last child of an aggr_kprobe */ |
836 | old_p = list_entry(p->list.next, struct kprobe, list); |
837 | list_del(&p->list); |
838 | arch_remove_kprobe(old_p); |
839 | kfree(old_p); |
840 | } |
841 | } |
842 | |
843 | int __kprobes register_kprobes(struct kprobe **kps, int num) |
844 | { |
845 | int i, ret = 0; |
846 | |
847 | if (num <= 0) |
848 | return -EINVAL; |
849 | for (i = 0; i < num; i++) { |
850 | ret = register_kprobe(kps[i]); |
851 | if (ret < 0) { |
852 | if (i > 0) |
853 | unregister_kprobes(kps, i); |
854 | break; |
855 | } |
856 | } |
857 | return ret; |
858 | } |
859 | EXPORT_SYMBOL_GPL(register_kprobes); |
860 | |
861 | void __kprobes unregister_kprobe(struct kprobe *p) |
862 | { |
863 | unregister_kprobes(&p, 1); |
864 | } |
865 | EXPORT_SYMBOL_GPL(unregister_kprobe); |
866 | |
867 | void __kprobes unregister_kprobes(struct kprobe **kps, int num) |
868 | { |
869 | int i; |
870 | |
871 | if (num <= 0) |
872 | return; |
873 | mutex_lock(&kprobe_mutex); |
874 | for (i = 0; i < num; i++) |
875 | if (__unregister_kprobe_top(kps[i]) < 0) |
876 | kps[i]->addr = NULL; |
877 | mutex_unlock(&kprobe_mutex); |
878 | |
879 | synchronize_sched(); |
880 | for (i = 0; i < num; i++) |
881 | if (kps[i]->addr) |
882 | __unregister_kprobe_bottom(kps[i]); |
883 | } |
884 | EXPORT_SYMBOL_GPL(unregister_kprobes); |
885 | |
886 | static struct notifier_block kprobe_exceptions_nb = { |
887 | .notifier_call = kprobe_exceptions_notify, |
888 | .priority = 0x7fffffff /* we need to be notified first */ |
889 | }; |
890 | |
891 | unsigned long __weak arch_deref_entry_point(void *entry) |
892 | { |
893 | return (unsigned long)entry; |
894 | } |
895 | |
896 | int __kprobes register_jprobes(struct jprobe **jps, int num) |
897 | { |
898 | struct jprobe *jp; |
899 | int ret = 0, i; |
900 | |
901 | if (num <= 0) |
902 | return -EINVAL; |
903 | for (i = 0; i < num; i++) { |
904 | unsigned long addr; |
905 | jp = jps[i]; |
906 | addr = arch_deref_entry_point(jp->entry); |
907 | |
908 | if (!kernel_text_address(addr)) |
909 | ret = -EINVAL; |
910 | else { |
911 | /* Todo: Verify probepoint is a function entry point */ |
912 | jp->kp.pre_handler = setjmp_pre_handler; |
913 | jp->kp.break_handler = longjmp_break_handler; |
914 | ret = register_kprobe(&jp->kp); |
915 | } |
916 | if (ret < 0) { |
917 | if (i > 0) |
918 | unregister_jprobes(jps, i); |
919 | break; |
920 | } |
921 | } |
922 | return ret; |
923 | } |
924 | EXPORT_SYMBOL_GPL(register_jprobes); |
925 | |
926 | int __kprobes register_jprobe(struct jprobe *jp) |
927 | { |
928 | return register_jprobes(&jp, 1); |
929 | } |
930 | EXPORT_SYMBOL_GPL(register_jprobe); |
931 | |
932 | void __kprobes unregister_jprobe(struct jprobe *jp) |
933 | { |
934 | unregister_jprobes(&jp, 1); |
935 | } |
936 | EXPORT_SYMBOL_GPL(unregister_jprobe); |
937 | |
938 | void __kprobes unregister_jprobes(struct jprobe **jps, int num) |
939 | { |
940 | int i; |
941 | |
942 | if (num <= 0) |
943 | return; |
944 | mutex_lock(&kprobe_mutex); |
945 | for (i = 0; i < num; i++) |
946 | if (__unregister_kprobe_top(&jps[i]->kp) < 0) |
947 | jps[i]->kp.addr = NULL; |
948 | mutex_unlock(&kprobe_mutex); |
949 | |
950 | synchronize_sched(); |
951 | for (i = 0; i < num; i++) { |
952 | if (jps[i]->kp.addr) |
953 | __unregister_kprobe_bottom(&jps[i]->kp); |
954 | } |
955 | } |
956 | EXPORT_SYMBOL_GPL(unregister_jprobes); |
957 | |
958 | #ifdef CONFIG_KRETPROBES |
959 | /* |
960 | * This kprobe pre_handler is registered with every kretprobe. When probe |
961 | * hits it will set up the return probe. |
962 | */ |
963 | static int __kprobes pre_handler_kretprobe(struct kprobe *p, |
964 | struct pt_regs *regs) |
965 | { |
966 | struct kretprobe *rp = container_of(p, struct kretprobe, kp); |
967 | unsigned long hash, flags = 0; |
968 | struct kretprobe_instance *ri; |
969 | |
970 | /*TODO: consider to only swap the RA after the last pre_handler fired */ |
971 | hash = hash_ptr(current, KPROBE_HASH_BITS); |
972 | spin_lock_irqsave(&rp->lock, flags); |
973 | if (!hlist_empty(&rp->free_instances)) { |
974 | ri = hlist_entry(rp->free_instances.first, |
975 | struct kretprobe_instance, hlist); |
976 | hlist_del(&ri->hlist); |
977 | spin_unlock_irqrestore(&rp->lock, flags); |
978 | |
979 | ri->rp = rp; |
980 | ri->task = current; |
981 | |
982 | if (rp->entry_handler && rp->entry_handler(ri, regs)) |
983 | return 0; |
984 | |
985 | arch_prepare_kretprobe(ri, regs); |
986 | |
987 | /* XXX(hch): why is there no hlist_move_head? */ |
988 | INIT_HLIST_NODE(&ri->hlist); |
989 | kretprobe_table_lock(hash, &flags); |
990 | hlist_add_head(&ri->hlist, &kretprobe_inst_table[hash]); |
991 | kretprobe_table_unlock(hash, &flags); |
992 | } else { |
993 | rp->nmissed++; |
994 | spin_unlock_irqrestore(&rp->lock, flags); |
995 | } |
996 | return 0; |
997 | } |
998 | |
999 | int __kprobes register_kretprobe(struct kretprobe *rp) |
1000 | { |
1001 | int ret = 0; |
1002 | struct kretprobe_instance *inst; |
1003 | int i; |
1004 | void *addr; |
1005 | |
1006 | if (kretprobe_blacklist_size) { |
1007 | addr = kprobe_addr(&rp->kp); |
1008 | if (!addr) |
1009 | return -EINVAL; |
1010 | |
1011 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { |
1012 | if (kretprobe_blacklist[i].addr == addr) |
1013 | return -EINVAL; |
1014 | } |
1015 | } |
1016 | |
1017 | rp->kp.pre_handler = pre_handler_kretprobe; |
1018 | rp->kp.post_handler = NULL; |
1019 | rp->kp.fault_handler = NULL; |
1020 | rp->kp.break_handler = NULL; |
1021 | |
1022 | /* Pre-allocate memory for max kretprobe instances */ |
1023 | if (rp->maxactive <= 0) { |
1024 | #ifdef CONFIG_PREEMPT |
1025 | rp->maxactive = max(10, 2 * NR_CPUS); |
1026 | #else |
1027 | rp->maxactive = NR_CPUS; |
1028 | #endif |
1029 | } |
1030 | spin_lock_init(&rp->lock); |
1031 | INIT_HLIST_HEAD(&rp->free_instances); |
1032 | for (i = 0; i < rp->maxactive; i++) { |
1033 | inst = kmalloc(sizeof(struct kretprobe_instance) + |
1034 | rp->data_size, GFP_KERNEL); |
1035 | if (inst == NULL) { |
1036 | free_rp_inst(rp); |
1037 | return -ENOMEM; |
1038 | } |
1039 | INIT_HLIST_NODE(&inst->hlist); |
1040 | hlist_add_head(&inst->hlist, &rp->free_instances); |
1041 | } |
1042 | |
1043 | rp->nmissed = 0; |
1044 | /* Establish function entry probe point */ |
1045 | ret = register_kprobe(&rp->kp); |
1046 | if (ret != 0) |
1047 | free_rp_inst(rp); |
1048 | return ret; |
1049 | } |
1050 | EXPORT_SYMBOL_GPL(register_kretprobe); |
1051 | |
1052 | int __kprobes register_kretprobes(struct kretprobe **rps, int num) |
1053 | { |
1054 | int ret = 0, i; |
1055 | |
1056 | if (num <= 0) |
1057 | return -EINVAL; |
1058 | for (i = 0; i < num; i++) { |
1059 | ret = register_kretprobe(rps[i]); |
1060 | if (ret < 0) { |
1061 | if (i > 0) |
1062 | unregister_kretprobes(rps, i); |
1063 | break; |
1064 | } |
1065 | } |
1066 | return ret; |
1067 | } |
1068 | EXPORT_SYMBOL_GPL(register_kretprobes); |
1069 | |
1070 | void __kprobes unregister_kretprobe(struct kretprobe *rp) |
1071 | { |
1072 | unregister_kretprobes(&rp, 1); |
1073 | } |
1074 | EXPORT_SYMBOL_GPL(unregister_kretprobe); |
1075 | |
1076 | void __kprobes unregister_kretprobes(struct kretprobe **rps, int num) |
1077 | { |
1078 | int i; |
1079 | |
1080 | if (num <= 0) |
1081 | return; |
1082 | mutex_lock(&kprobe_mutex); |
1083 | for (i = 0; i < num; i++) |
1084 | if (__unregister_kprobe_top(&rps[i]->kp) < 0) |
1085 | rps[i]->kp.addr = NULL; |
1086 | mutex_unlock(&kprobe_mutex); |
1087 | |
1088 | synchronize_sched(); |
1089 | for (i = 0; i < num; i++) { |
1090 | if (rps[i]->kp.addr) { |
1091 | __unregister_kprobe_bottom(&rps[i]->kp); |
1092 | cleanup_rp_inst(rps[i]); |
1093 | } |
1094 | } |
1095 | } |
1096 | EXPORT_SYMBOL_GPL(unregister_kretprobes); |
1097 | |
1098 | #else /* CONFIG_KRETPROBES */ |
1099 | int __kprobes register_kretprobe(struct kretprobe *rp) |
1100 | { |
1101 | return -ENOSYS; |
1102 | } |
1103 | EXPORT_SYMBOL_GPL(register_kretprobe); |
1104 | |
1105 | int __kprobes register_kretprobes(struct kretprobe **rps, int num) |
1106 | { |
1107 | return -ENOSYS; |
1108 | } |
1109 | EXPORT_SYMBOL_GPL(register_kretprobes); |
1110 | |
1111 | void __kprobes unregister_kretprobe(struct kretprobe *rp) |
1112 | { |
1113 | } |
1114 | EXPORT_SYMBOL_GPL(unregister_kretprobe); |
1115 | |
1116 | void __kprobes unregister_kretprobes(struct kretprobe **rps, int num) |
1117 | { |
1118 | } |
1119 | EXPORT_SYMBOL_GPL(unregister_kretprobes); |
1120 | |
1121 | static int __kprobes pre_handler_kretprobe(struct kprobe *p, |
1122 | struct pt_regs *regs) |
1123 | { |
1124 | return 0; |
1125 | } |
1126 | |
1127 | #endif /* CONFIG_KRETPROBES */ |
1128 | |
1129 | /* Set the kprobe gone and remove its instruction buffer. */ |
1130 | static void __kprobes kill_kprobe(struct kprobe *p) |
1131 | { |
1132 | struct kprobe *kp; |
1133 | |
1134 | p->flags |= KPROBE_FLAG_GONE; |
1135 | if (p->pre_handler == aggr_pre_handler) { |
1136 | /* |
1137 | * If this is an aggr_kprobe, we have to list all the |
1138 | * chained probes and mark them GONE. |
1139 | */ |
1140 | list_for_each_entry_rcu(kp, &p->list, list) |
1141 | kp->flags |= KPROBE_FLAG_GONE; |
1142 | p->post_handler = NULL; |
1143 | p->break_handler = NULL; |
1144 | } |
1145 | /* |
1146 | * Here, we can remove insn_slot safely, because no thread calls |
1147 | * the original probed function (which will be freed soon) any more. |
1148 | */ |
1149 | arch_remove_kprobe(p); |
1150 | } |
1151 | |
1152 | /* Module notifier call back, checking kprobes on the module */ |
1153 | static int __kprobes kprobes_module_callback(struct notifier_block *nb, |
1154 | unsigned long val, void *data) |
1155 | { |
1156 | struct module *mod = data; |
1157 | struct hlist_head *head; |
1158 | struct hlist_node *node; |
1159 | struct kprobe *p; |
1160 | unsigned int i; |
1161 | int checkcore = (val == MODULE_STATE_GOING); |
1162 | |
1163 | if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE) |
1164 | return NOTIFY_DONE; |
1165 | |
1166 | /* |
1167 | * When MODULE_STATE_GOING was notified, both of module .text and |
1168 | * .init.text sections would be freed. When MODULE_STATE_LIVE was |
1169 | * notified, only .init.text section would be freed. We need to |
1170 | * disable kprobes which have been inserted in the sections. |
1171 | */ |
1172 | mutex_lock(&kprobe_mutex); |
1173 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
1174 | head = &kprobe_table[i]; |
1175 | hlist_for_each_entry_rcu(p, node, head, hlist) |
1176 | if (within_module_init((unsigned long)p->addr, mod) || |
1177 | (checkcore && |
1178 | within_module_core((unsigned long)p->addr, mod))) { |
1179 | /* |
1180 | * The vaddr this probe is installed will soon |
1181 | * be vfreed buy not synced to disk. Hence, |
1182 | * disarming the breakpoint isn't needed. |
1183 | */ |
1184 | kill_kprobe(p); |
1185 | } |
1186 | } |
1187 | mutex_unlock(&kprobe_mutex); |
1188 | return NOTIFY_DONE; |
1189 | } |
1190 | |
1191 | static struct notifier_block kprobe_module_nb = { |
1192 | .notifier_call = kprobes_module_callback, |
1193 | .priority = 0 |
1194 | }; |
1195 | |
1196 | static int __init init_kprobes(void) |
1197 | { |
1198 | int i, err = 0; |
1199 | unsigned long offset = 0, size = 0; |
1200 | char *modname, namebuf[128]; |
1201 | const char *symbol_name; |
1202 | void *addr; |
1203 | struct kprobe_blackpoint *kb; |
1204 | |
1205 | /* FIXME allocate the probe table, currently defined statically */ |
1206 | /* initialize all list heads */ |
1207 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
1208 | INIT_HLIST_HEAD(&kprobe_table[i]); |
1209 | INIT_HLIST_HEAD(&kretprobe_inst_table[i]); |
1210 | spin_lock_init(&(kretprobe_table_locks[i].lock)); |
1211 | } |
1212 | |
1213 | /* |
1214 | * Lookup and populate the kprobe_blacklist. |
1215 | * |
1216 | * Unlike the kretprobe blacklist, we'll need to determine |
1217 | * the range of addresses that belong to the said functions, |
1218 | * since a kprobe need not necessarily be at the beginning |
1219 | * of a function. |
1220 | */ |
1221 | for (kb = kprobe_blacklist; kb->name != NULL; kb++) { |
1222 | kprobe_lookup_name(kb->name, addr); |
1223 | if (!addr) |
1224 | continue; |
1225 | |
1226 | kb->start_addr = (unsigned long)addr; |
1227 | symbol_name = kallsyms_lookup(kb->start_addr, |
1228 | &size, &offset, &modname, namebuf); |
1229 | if (!symbol_name) |
1230 | kb->range = 0; |
1231 | else |
1232 | kb->range = size; |
1233 | } |
1234 | |
1235 | if (kretprobe_blacklist_size) { |
1236 | /* lookup the function address from its name */ |
1237 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { |
1238 | kprobe_lookup_name(kretprobe_blacklist[i].name, |
1239 | kretprobe_blacklist[i].addr); |
1240 | if (!kretprobe_blacklist[i].addr) |
1241 | printk("kretprobe: lookup failed: %s\n", |
1242 | kretprobe_blacklist[i].name); |
1243 | } |
1244 | } |
1245 | |
1246 | /* By default, kprobes are armed */ |
1247 | kprobes_all_disarmed = false; |
1248 | |
1249 | err = arch_init_kprobes(); |
1250 | if (!err) |
1251 | err = register_die_notifier(&kprobe_exceptions_nb); |
1252 | if (!err) |
1253 | err = register_module_notifier(&kprobe_module_nb); |
1254 | |
1255 | kprobes_initialized = (err == 0); |
1256 | |
1257 | if (!err) |
1258 | init_test_probes(); |
1259 | return err; |
1260 | } |
1261 | |
1262 | #ifdef CONFIG_DEBUG_FS |
1263 | static void __kprobes report_probe(struct seq_file *pi, struct kprobe *p, |
1264 | const char *sym, int offset,char *modname) |
1265 | { |
1266 | char *kprobe_type; |
1267 | |
1268 | if (p->pre_handler == pre_handler_kretprobe) |
1269 | kprobe_type = "r"; |
1270 | else if (p->pre_handler == setjmp_pre_handler) |
1271 | kprobe_type = "j"; |
1272 | else |
1273 | kprobe_type = "k"; |
1274 | if (sym) |
1275 | seq_printf(pi, "%p %s %s+0x%x %s %s%s\n", |
1276 | p->addr, kprobe_type, sym, offset, |
1277 | (modname ? modname : " "), |
1278 | (kprobe_gone(p) ? "[GONE]" : ""), |
1279 | ((kprobe_disabled(p) && !kprobe_gone(p)) ? |
1280 | "[DISABLED]" : "")); |
1281 | else |
1282 | seq_printf(pi, "%p %s %p %s%s\n", |
1283 | p->addr, kprobe_type, p->addr, |
1284 | (kprobe_gone(p) ? "[GONE]" : ""), |
1285 | ((kprobe_disabled(p) && !kprobe_gone(p)) ? |
1286 | "[DISABLED]" : "")); |
1287 | } |
1288 | |
1289 | static void __kprobes *kprobe_seq_start(struct seq_file *f, loff_t *pos) |
1290 | { |
1291 | return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL; |
1292 | } |
1293 | |
1294 | static void __kprobes *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos) |
1295 | { |
1296 | (*pos)++; |
1297 | if (*pos >= KPROBE_TABLE_SIZE) |
1298 | return NULL; |
1299 | return pos; |
1300 | } |
1301 | |
1302 | static void __kprobes kprobe_seq_stop(struct seq_file *f, void *v) |
1303 | { |
1304 | /* Nothing to do */ |
1305 | } |
1306 | |
1307 | static int __kprobes show_kprobe_addr(struct seq_file *pi, void *v) |
1308 | { |
1309 | struct hlist_head *head; |
1310 | struct hlist_node *node; |
1311 | struct kprobe *p, *kp; |
1312 | const char *sym = NULL; |
1313 | unsigned int i = *(loff_t *) v; |
1314 | unsigned long offset = 0; |
1315 | char *modname, namebuf[128]; |
1316 | |
1317 | head = &kprobe_table[i]; |
1318 | preempt_disable(); |
1319 | hlist_for_each_entry_rcu(p, node, head, hlist) { |
1320 | sym = kallsyms_lookup((unsigned long)p->addr, NULL, |
1321 | &offset, &modname, namebuf); |
1322 | if (p->pre_handler == aggr_pre_handler) { |
1323 | list_for_each_entry_rcu(kp, &p->list, list) |
1324 | report_probe(pi, kp, sym, offset, modname); |
1325 | } else |
1326 | report_probe(pi, p, sym, offset, modname); |
1327 | } |
1328 | preempt_enable(); |
1329 | return 0; |
1330 | } |
1331 | |
1332 | static struct seq_operations kprobes_seq_ops = { |
1333 | .start = kprobe_seq_start, |
1334 | .next = kprobe_seq_next, |
1335 | .stop = kprobe_seq_stop, |
1336 | .show = show_kprobe_addr |
1337 | }; |
1338 | |
1339 | static int __kprobes kprobes_open(struct inode *inode, struct file *filp) |
1340 | { |
1341 | return seq_open(filp, &kprobes_seq_ops); |
1342 | } |
1343 | |
1344 | static struct file_operations debugfs_kprobes_operations = { |
1345 | .open = kprobes_open, |
1346 | .read = seq_read, |
1347 | .llseek = seq_lseek, |
1348 | .release = seq_release, |
1349 | }; |
1350 | |
1351 | /* Disable one kprobe */ |
1352 | int __kprobes disable_kprobe(struct kprobe *kp) |
1353 | { |
1354 | int ret = 0; |
1355 | struct kprobe *p; |
1356 | |
1357 | mutex_lock(&kprobe_mutex); |
1358 | |
1359 | /* Check whether specified probe is valid. */ |
1360 | p = __get_valid_kprobe(kp); |
1361 | if (unlikely(p == NULL)) { |
1362 | ret = -EINVAL; |
1363 | goto out; |
1364 | } |
1365 | |
1366 | /* If the probe is already disabled (or gone), just return */ |
1367 | if (kprobe_disabled(kp)) |
1368 | goto out; |
1369 | |
1370 | kp->flags |= KPROBE_FLAG_DISABLED; |
1371 | if (p != kp) |
1372 | /* When kp != p, p is always enabled. */ |
1373 | try_to_disable_aggr_kprobe(p); |
1374 | |
1375 | if (!kprobes_all_disarmed && kprobe_disabled(p)) |
1376 | disarm_kprobe(p); |
1377 | out: |
1378 | mutex_unlock(&kprobe_mutex); |
1379 | return ret; |
1380 | } |
1381 | EXPORT_SYMBOL_GPL(disable_kprobe); |
1382 | |
1383 | /* Enable one kprobe */ |
1384 | int __kprobes enable_kprobe(struct kprobe *kp) |
1385 | { |
1386 | int ret = 0; |
1387 | struct kprobe *p; |
1388 | |
1389 | mutex_lock(&kprobe_mutex); |
1390 | |
1391 | /* Check whether specified probe is valid. */ |
1392 | p = __get_valid_kprobe(kp); |
1393 | if (unlikely(p == NULL)) { |
1394 | ret = -EINVAL; |
1395 | goto out; |
1396 | } |
1397 | |
1398 | if (kprobe_gone(kp)) { |
1399 | /* This kprobe has gone, we couldn't enable it. */ |
1400 | ret = -EINVAL; |
1401 | goto out; |
1402 | } |
1403 | |
1404 | if (!kprobes_all_disarmed && kprobe_disabled(p)) |
1405 | arm_kprobe(p); |
1406 | |
1407 | p->flags &= ~KPROBE_FLAG_DISABLED; |
1408 | if (p != kp) |
1409 | kp->flags &= ~KPROBE_FLAG_DISABLED; |
1410 | out: |
1411 | mutex_unlock(&kprobe_mutex); |
1412 | return ret; |
1413 | } |
1414 | EXPORT_SYMBOL_GPL(enable_kprobe); |
1415 | |
1416 | static void __kprobes arm_all_kprobes(void) |
1417 | { |
1418 | struct hlist_head *head; |
1419 | struct hlist_node *node; |
1420 | struct kprobe *p; |
1421 | unsigned int i; |
1422 | |
1423 | mutex_lock(&kprobe_mutex); |
1424 | |
1425 | /* If kprobes are armed, just return */ |
1426 | if (!kprobes_all_disarmed) |
1427 | goto already_enabled; |
1428 | |
1429 | mutex_lock(&text_mutex); |
1430 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
1431 | head = &kprobe_table[i]; |
1432 | hlist_for_each_entry_rcu(p, node, head, hlist) |
1433 | if (!kprobe_disabled(p)) |
1434 | arch_arm_kprobe(p); |
1435 | } |
1436 | mutex_unlock(&text_mutex); |
1437 | |
1438 | kprobes_all_disarmed = false; |
1439 | printk(KERN_INFO "Kprobes globally enabled\n"); |
1440 | |
1441 | already_enabled: |
1442 | mutex_unlock(&kprobe_mutex); |
1443 | return; |
1444 | } |
1445 | |
1446 | static void __kprobes disarm_all_kprobes(void) |
1447 | { |
1448 | struct hlist_head *head; |
1449 | struct hlist_node *node; |
1450 | struct kprobe *p; |
1451 | unsigned int i; |
1452 | |
1453 | mutex_lock(&kprobe_mutex); |
1454 | |
1455 | /* If kprobes are already disarmed, just return */ |
1456 | if (kprobes_all_disarmed) |
1457 | goto already_disabled; |
1458 | |
1459 | kprobes_all_disarmed = true; |
1460 | printk(KERN_INFO "Kprobes globally disabled\n"); |
1461 | mutex_lock(&text_mutex); |
1462 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
1463 | head = &kprobe_table[i]; |
1464 | hlist_for_each_entry_rcu(p, node, head, hlist) { |
1465 | if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p)) |
1466 | arch_disarm_kprobe(p); |
1467 | } |
1468 | } |
1469 | |
1470 | mutex_unlock(&text_mutex); |
1471 | mutex_unlock(&kprobe_mutex); |
1472 | /* Allow all currently running kprobes to complete */ |
1473 | synchronize_sched(); |
1474 | return; |
1475 | |
1476 | already_disabled: |
1477 | mutex_unlock(&kprobe_mutex); |
1478 | return; |
1479 | } |
1480 | |
1481 | /* |
1482 | * XXX: The debugfs bool file interface doesn't allow for callbacks |
1483 | * when the bool state is switched. We can reuse that facility when |
1484 | * available |
1485 | */ |
1486 | static ssize_t read_enabled_file_bool(struct file *file, |
1487 | char __user *user_buf, size_t count, loff_t *ppos) |
1488 | { |
1489 | char buf[3]; |
1490 | |
1491 | if (!kprobes_all_disarmed) |
1492 | buf[0] = '1'; |
1493 | else |
1494 | buf[0] = '0'; |
1495 | buf[1] = '\n'; |
1496 | buf[2] = 0x00; |
1497 | return simple_read_from_buffer(user_buf, count, ppos, buf, 2); |
1498 | } |
1499 | |
1500 | static ssize_t write_enabled_file_bool(struct file *file, |
1501 | const char __user *user_buf, size_t count, loff_t *ppos) |
1502 | { |
1503 | char buf[32]; |
1504 | int buf_size; |
1505 | |
1506 | buf_size = min(count, (sizeof(buf)-1)); |
1507 | if (copy_from_user(buf, user_buf, buf_size)) |
1508 | return -EFAULT; |
1509 | |
1510 | switch (buf[0]) { |
1511 | case 'y': |
1512 | case 'Y': |
1513 | case '1': |
1514 | arm_all_kprobes(); |
1515 | break; |
1516 | case 'n': |
1517 | case 'N': |
1518 | case '0': |
1519 | disarm_all_kprobes(); |
1520 | break; |
1521 | } |
1522 | |
1523 | return count; |
1524 | } |
1525 | |
1526 | static struct file_operations fops_kp = { |
1527 | .read = read_enabled_file_bool, |
1528 | .write = write_enabled_file_bool, |
1529 | }; |
1530 | |
1531 | static int __kprobes debugfs_kprobe_init(void) |
1532 | { |
1533 | struct dentry *dir, *file; |
1534 | unsigned int value = 1; |
1535 | |
1536 | dir = debugfs_create_dir("kprobes", NULL); |
1537 | if (!dir) |
1538 | return -ENOMEM; |
1539 | |
1540 | file = debugfs_create_file("list", 0444, dir, NULL, |
1541 | &debugfs_kprobes_operations); |
1542 | if (!file) { |
1543 | debugfs_remove(dir); |
1544 | return -ENOMEM; |
1545 | } |
1546 | |
1547 | file = debugfs_create_file("enabled", 0600, dir, |
1548 | &value, &fops_kp); |
1549 | if (!file) { |
1550 | debugfs_remove(dir); |
1551 | return -ENOMEM; |
1552 | } |
1553 | |
1554 | return 0; |
1555 | } |
1556 | |
1557 | late_initcall(debugfs_kprobe_init); |
1558 | #endif /* CONFIG_DEBUG_FS */ |
1559 | |
1560 | module_init(init_kprobes); |
1561 | |
1562 | /* defined in arch/.../kernel/kprobes.c */ |
1563 | EXPORT_SYMBOL_GPL(jprobe_return); |
1564 |
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