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1// SPDX-License-Identifier: GPL-2.0-only
2/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
3 */
4#include <linux/bpf.h>
5#include <linux/btf.h>
6#include <linux/bpf-cgroup.h>
7#include <linux/cgroup.h>
8#include <linux/rcupdate.h>
9#include <linux/random.h>
10#include <linux/smp.h>
11#include <linux/topology.h>
12#include <linux/ktime.h>
13#include <linux/sched.h>
14#include <linux/uidgid.h>
15#include <linux/filter.h>
16#include <linux/ctype.h>
17#include <linux/jiffies.h>
18#include <linux/pid_namespace.h>
19#include <linux/poison.h>
20#include <linux/proc_ns.h>
21#include <linux/security.h>
22#include <linux/btf_ids.h>
23#include <linux/bpf_mem_alloc.h>
24
25#include "../../lib/kstrtox.h"
26
27/* If kernel subsystem is allowing eBPF programs to call this function,
28 * inside its own verifier_ops->get_func_proto() callback it should return
29 * bpf_map_lookup_elem_proto, so that verifier can properly check the arguments
30 *
31 * Different map implementations will rely on rcu in map methods
32 * lookup/update/delete, therefore eBPF programs must run under rcu lock
33 * if program is allowed to access maps, so check rcu_read_lock_held in
34 * all three functions.
35 */
36BPF_CALL_2(bpf_map_lookup_elem, struct bpf_map *, map, void *, key)
37{
38 WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
39 return (unsigned long) map->ops->map_lookup_elem(map, key);
40}
41
42const struct bpf_func_proto bpf_map_lookup_elem_proto = {
43 .func = bpf_map_lookup_elem,
44 .gpl_only = false,
45 .pkt_access = true,
46 .ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL,
47 .arg1_type = ARG_CONST_MAP_PTR,
48 .arg2_type = ARG_PTR_TO_MAP_KEY,
49};
50
51BPF_CALL_4(bpf_map_update_elem, struct bpf_map *, map, void *, key,
52 void *, value, u64, flags)
53{
54 WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
55 return map->ops->map_update_elem(map, key, value, flags);
56}
57
58const struct bpf_func_proto bpf_map_update_elem_proto = {
59 .func = bpf_map_update_elem,
60 .gpl_only = false,
61 .pkt_access = true,
62 .ret_type = RET_INTEGER,
63 .arg1_type = ARG_CONST_MAP_PTR,
64 .arg2_type = ARG_PTR_TO_MAP_KEY,
65 .arg3_type = ARG_PTR_TO_MAP_VALUE,
66 .arg4_type = ARG_ANYTHING,
67};
68
69BPF_CALL_2(bpf_map_delete_elem, struct bpf_map *, map, void *, key)
70{
71 WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
72 return map->ops->map_delete_elem(map, key);
73}
74
75const struct bpf_func_proto bpf_map_delete_elem_proto = {
76 .func = bpf_map_delete_elem,
77 .gpl_only = false,
78 .pkt_access = true,
79 .ret_type = RET_INTEGER,
80 .arg1_type = ARG_CONST_MAP_PTR,
81 .arg2_type = ARG_PTR_TO_MAP_KEY,
82};
83
84BPF_CALL_3(bpf_map_push_elem, struct bpf_map *, map, void *, value, u64, flags)
85{
86 return map->ops->map_push_elem(map, value, flags);
87}
88
89const struct bpf_func_proto bpf_map_push_elem_proto = {
90 .func = bpf_map_push_elem,
91 .gpl_only = false,
92 .pkt_access = true,
93 .ret_type = RET_INTEGER,
94 .arg1_type = ARG_CONST_MAP_PTR,
95 .arg2_type = ARG_PTR_TO_MAP_VALUE,
96 .arg3_type = ARG_ANYTHING,
97};
98
99BPF_CALL_2(bpf_map_pop_elem, struct bpf_map *, map, void *, value)
100{
101 return map->ops->map_pop_elem(map, value);
102}
103
104const struct bpf_func_proto bpf_map_pop_elem_proto = {
105 .func = bpf_map_pop_elem,
106 .gpl_only = false,
107 .ret_type = RET_INTEGER,
108 .arg1_type = ARG_CONST_MAP_PTR,
109 .arg2_type = ARG_PTR_TO_MAP_VALUE | MEM_UNINIT,
110};
111
112BPF_CALL_2(bpf_map_peek_elem, struct bpf_map *, map, void *, value)
113{
114 return map->ops->map_peek_elem(map, value);
115}
116
117const struct bpf_func_proto bpf_map_peek_elem_proto = {
118 .func = bpf_map_peek_elem,
119 .gpl_only = false,
120 .ret_type = RET_INTEGER,
121 .arg1_type = ARG_CONST_MAP_PTR,
122 .arg2_type = ARG_PTR_TO_MAP_VALUE | MEM_UNINIT,
123};
124
125BPF_CALL_3(bpf_map_lookup_percpu_elem, struct bpf_map *, map, void *, key, u32, cpu)
126{
127 WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
128 return (unsigned long) map->ops->map_lookup_percpu_elem(map, key, cpu);
129}
130
131const struct bpf_func_proto bpf_map_lookup_percpu_elem_proto = {
132 .func = bpf_map_lookup_percpu_elem,
133 .gpl_only = false,
134 .pkt_access = true,
135 .ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL,
136 .arg1_type = ARG_CONST_MAP_PTR,
137 .arg2_type = ARG_PTR_TO_MAP_KEY,
138 .arg3_type = ARG_ANYTHING,
139};
140
141const struct bpf_func_proto bpf_get_prandom_u32_proto = {
142 .func = bpf_user_rnd_u32,
143 .gpl_only = false,
144 .ret_type = RET_INTEGER,
145};
146
147BPF_CALL_0(bpf_get_smp_processor_id)
148{
149 return smp_processor_id();
150}
151
152const struct bpf_func_proto bpf_get_smp_processor_id_proto = {
153 .func = bpf_get_smp_processor_id,
154 .gpl_only = false,
155 .ret_type = RET_INTEGER,
156};
157
158BPF_CALL_0(bpf_get_numa_node_id)
159{
160 return numa_node_id();
161}
162
163const struct bpf_func_proto bpf_get_numa_node_id_proto = {
164 .func = bpf_get_numa_node_id,
165 .gpl_only = false,
166 .ret_type = RET_INTEGER,
167};
168
169BPF_CALL_0(bpf_ktime_get_ns)
170{
171 /* NMI safe access to clock monotonic */
172 return ktime_get_mono_fast_ns();
173}
174
175const struct bpf_func_proto bpf_ktime_get_ns_proto = {
176 .func = bpf_ktime_get_ns,
177 .gpl_only = false,
178 .ret_type = RET_INTEGER,
179};
180
181BPF_CALL_0(bpf_ktime_get_boot_ns)
182{
183 /* NMI safe access to clock boottime */
184 return ktime_get_boot_fast_ns();
185}
186
187const struct bpf_func_proto bpf_ktime_get_boot_ns_proto = {
188 .func = bpf_ktime_get_boot_ns,
189 .gpl_only = false,
190 .ret_type = RET_INTEGER,
191};
192
193BPF_CALL_0(bpf_ktime_get_coarse_ns)
194{
195 return ktime_get_coarse_ns();
196}
197
198const struct bpf_func_proto bpf_ktime_get_coarse_ns_proto = {
199 .func = bpf_ktime_get_coarse_ns,
200 .gpl_only = false,
201 .ret_type = RET_INTEGER,
202};
203
204BPF_CALL_0(bpf_ktime_get_tai_ns)
205{
206 /* NMI safe access to clock tai */
207 return ktime_get_tai_fast_ns();
208}
209
210const struct bpf_func_proto bpf_ktime_get_tai_ns_proto = {
211 .func = bpf_ktime_get_tai_ns,
212 .gpl_only = false,
213 .ret_type = RET_INTEGER,
214};
215
216BPF_CALL_0(bpf_get_current_pid_tgid)
217{
218 struct task_struct *task = current;
219
220 if (unlikely(!task))
221 return -EINVAL;
222
223 return (u64) task->tgid << 32 | task->pid;
224}
225
226const struct bpf_func_proto bpf_get_current_pid_tgid_proto = {
227 .func = bpf_get_current_pid_tgid,
228 .gpl_only = false,
229 .ret_type = RET_INTEGER,
230};
231
232BPF_CALL_0(bpf_get_current_uid_gid)
233{
234 struct task_struct *task = current;
235 kuid_t uid;
236 kgid_t gid;
237
238 if (unlikely(!task))
239 return -EINVAL;
240
241 current_uid_gid(&uid, &gid);
242 return (u64) from_kgid(&init_user_ns, gid) << 32 |
243 from_kuid(&init_user_ns, uid);
244}
245
246const struct bpf_func_proto bpf_get_current_uid_gid_proto = {
247 .func = bpf_get_current_uid_gid,
248 .gpl_only = false,
249 .ret_type = RET_INTEGER,
250};
251
252BPF_CALL_2(bpf_get_current_comm, char *, buf, u32, size)
253{
254 struct task_struct *task = current;
255
256 if (unlikely(!task))
257 goto err_clear;
258
259 /* Verifier guarantees that size > 0 */
260 strscpy(buf, task->comm, size);
261 return 0;
262err_clear:
263 memset(buf, 0, size);
264 return -EINVAL;
265}
266
267const struct bpf_func_proto bpf_get_current_comm_proto = {
268 .func = bpf_get_current_comm,
269 .gpl_only = false,
270 .ret_type = RET_INTEGER,
271 .arg1_type = ARG_PTR_TO_UNINIT_MEM,
272 .arg2_type = ARG_CONST_SIZE,
273};
274
275#if defined(CONFIG_QUEUED_SPINLOCKS) || defined(CONFIG_BPF_ARCH_SPINLOCK)
276
277static inline void __bpf_spin_lock(struct bpf_spin_lock *lock)
278{
279 arch_spinlock_t *l = (void *)lock;
280 union {
281 __u32 val;
282 arch_spinlock_t lock;
283 } u = { .lock = __ARCH_SPIN_LOCK_UNLOCKED };
284
285 compiletime_assert(u.val == 0, "__ARCH_SPIN_LOCK_UNLOCKED not 0");
286 BUILD_BUG_ON(sizeof(*l) != sizeof(__u32));
287 BUILD_BUG_ON(sizeof(*lock) != sizeof(__u32));
288 arch_spin_lock(l);
289}
290
291static inline void __bpf_spin_unlock(struct bpf_spin_lock *lock)
292{
293 arch_spinlock_t *l = (void *)lock;
294
295 arch_spin_unlock(l);
296}
297
298#else
299
300static inline void __bpf_spin_lock(struct bpf_spin_lock *lock)
301{
302 atomic_t *l = (void *)lock;
303
304 BUILD_BUG_ON(sizeof(*l) != sizeof(*lock));
305 do {
306 atomic_cond_read_relaxed(l, !VAL);
307 } while (atomic_xchg(l, 1));
308}
309
310static inline void __bpf_spin_unlock(struct bpf_spin_lock *lock)
311{
312 atomic_t *l = (void *)lock;
313
314 atomic_set_release(l, 0);
315}
316
317#endif
318
319static DEFINE_PER_CPU(unsigned long, irqsave_flags);
320
321static inline void __bpf_spin_lock_irqsave(struct bpf_spin_lock *lock)
322{
323 unsigned long flags;
324
325 local_irq_save(flags);
326 __bpf_spin_lock(lock);
327 __this_cpu_write(irqsave_flags, flags);
328}
329
330notrace BPF_CALL_1(bpf_spin_lock, struct bpf_spin_lock *, lock)
331{
332 __bpf_spin_lock_irqsave(lock);
333 return 0;
334}
335
336const struct bpf_func_proto bpf_spin_lock_proto = {
337 .func = bpf_spin_lock,
338 .gpl_only = false,
339 .ret_type = RET_VOID,
340 .arg1_type = ARG_PTR_TO_SPIN_LOCK,
341 .arg1_btf_id = BPF_PTR_POISON,
342};
343
344static inline void __bpf_spin_unlock_irqrestore(struct bpf_spin_lock *lock)
345{
346 unsigned long flags;
347
348 flags = __this_cpu_read(irqsave_flags);
349 __bpf_spin_unlock(lock);
350 local_irq_restore(flags);
351}
352
353notrace BPF_CALL_1(bpf_spin_unlock, struct bpf_spin_lock *, lock)
354{
355 __bpf_spin_unlock_irqrestore(lock);
356 return 0;
357}
358
359const struct bpf_func_proto bpf_spin_unlock_proto = {
360 .func = bpf_spin_unlock,
361 .gpl_only = false,
362 .ret_type = RET_VOID,
363 .arg1_type = ARG_PTR_TO_SPIN_LOCK,
364 .arg1_btf_id = BPF_PTR_POISON,
365};
366
367void copy_map_value_locked(struct bpf_map *map, void *dst, void *src,
368 bool lock_src)
369{
370 struct bpf_spin_lock *lock;
371
372 if (lock_src)
373 lock = src + map->record->spin_lock_off;
374 else
375 lock = dst + map->record->spin_lock_off;
376 preempt_disable();
377 __bpf_spin_lock_irqsave(lock);
378 copy_map_value(map, dst, src);
379 __bpf_spin_unlock_irqrestore(lock);
380 preempt_enable();
381}
382
383BPF_CALL_0(bpf_jiffies64)
384{
385 return get_jiffies_64();
386}
387
388const struct bpf_func_proto bpf_jiffies64_proto = {
389 .func = bpf_jiffies64,
390 .gpl_only = false,
391 .ret_type = RET_INTEGER,
392};
393
394#ifdef CONFIG_CGROUPS
395BPF_CALL_0(bpf_get_current_cgroup_id)
396{
397 struct cgroup *cgrp;
398 u64 cgrp_id;
399
400 rcu_read_lock();
401 cgrp = task_dfl_cgroup(current);
402 cgrp_id = cgroup_id(cgrp);
403 rcu_read_unlock();
404
405 return cgrp_id;
406}
407
408const struct bpf_func_proto bpf_get_current_cgroup_id_proto = {
409 .func = bpf_get_current_cgroup_id,
410 .gpl_only = false,
411 .ret_type = RET_INTEGER,
412};
413
414BPF_CALL_1(bpf_get_current_ancestor_cgroup_id, int, ancestor_level)
415{
416 struct cgroup *cgrp;
417 struct cgroup *ancestor;
418 u64 cgrp_id;
419
420 rcu_read_lock();
421 cgrp = task_dfl_cgroup(current);
422 ancestor = cgroup_ancestor(cgrp, ancestor_level);
423 cgrp_id = ancestor ? cgroup_id(ancestor) : 0;
424 rcu_read_unlock();
425
426 return cgrp_id;
427}
428
429const struct bpf_func_proto bpf_get_current_ancestor_cgroup_id_proto = {
430 .func = bpf_get_current_ancestor_cgroup_id,
431 .gpl_only = false,
432 .ret_type = RET_INTEGER,
433 .arg1_type = ARG_ANYTHING,
434};
435#endif /* CONFIG_CGROUPS */
436
437#define BPF_STRTOX_BASE_MASK 0x1F
438
439static int __bpf_strtoull(const char *buf, size_t buf_len, u64 flags,
440 unsigned long long *res, bool *is_negative)
441{
442 unsigned int base = flags & BPF_STRTOX_BASE_MASK;
443 const char *cur_buf = buf;
444 size_t cur_len = buf_len;
445 unsigned int consumed;
446 size_t val_len;
447 char str[64];
448
449 if (!buf || !buf_len || !res || !is_negative)
450 return -EINVAL;
451
452 if (base != 0 && base != 8 && base != 10 && base != 16)
453 return -EINVAL;
454
455 if (flags & ~BPF_STRTOX_BASE_MASK)
456 return -EINVAL;
457
458 while (cur_buf < buf + buf_len && isspace(*cur_buf))
459 ++cur_buf;
460
461 *is_negative = (cur_buf < buf + buf_len && *cur_buf == '-');
462 if (*is_negative)
463 ++cur_buf;
464
465 consumed = cur_buf - buf;
466 cur_len -= consumed;
467 if (!cur_len)
468 return -EINVAL;
469
470 cur_len = min(cur_len, sizeof(str) - 1);
471 memcpy(str, cur_buf, cur_len);
472 str[cur_len] = '\0';
473 cur_buf = str;
474
475 cur_buf = _parse_integer_fixup_radix(cur_buf, &base);
476 val_len = _parse_integer(cur_buf, base, res);
477
478 if (val_len & KSTRTOX_OVERFLOW)
479 return -ERANGE;
480
481 if (val_len == 0)
482 return -EINVAL;
483
484 cur_buf += val_len;
485 consumed += cur_buf - str;
486
487 return consumed;
488}
489
490static int __bpf_strtoll(const char *buf, size_t buf_len, u64 flags,
491 long long *res)
492{
493 unsigned long long _res;
494 bool is_negative;
495 int err;
496
497 err = __bpf_strtoull(buf, buf_len, flags, &_res, &is_negative);
498 if (err < 0)
499 return err;
500 if (is_negative) {
501 if ((long long)-_res > 0)
502 return -ERANGE;
503 *res = -_res;
504 } else {
505 if ((long long)_res < 0)
506 return -ERANGE;
507 *res = _res;
508 }
509 return err;
510}
511
512BPF_CALL_4(bpf_strtol, const char *, buf, size_t, buf_len, u64, flags,
513 long *, res)
514{
515 long long _res;
516 int err;
517
518 err = __bpf_strtoll(buf, buf_len, flags, &_res);
519 if (err < 0)
520 return err;
521 if (_res != (long)_res)
522 return -ERANGE;
523 *res = _res;
524 return err;
525}
526
527const struct bpf_func_proto bpf_strtol_proto = {
528 .func = bpf_strtol,
529 .gpl_only = false,
530 .ret_type = RET_INTEGER,
531 .arg1_type = ARG_PTR_TO_MEM | MEM_RDONLY,
532 .arg2_type = ARG_CONST_SIZE,
533 .arg3_type = ARG_ANYTHING,
534 .arg4_type = ARG_PTR_TO_LONG,
535};
536
537BPF_CALL_4(bpf_strtoul, const char *, buf, size_t, buf_len, u64, flags,
538 unsigned long *, res)
539{
540 unsigned long long _res;
541 bool is_negative;
542 int err;
543
544 err = __bpf_strtoull(buf, buf_len, flags, &_res, &is_negative);
545 if (err < 0)
546 return err;
547 if (is_negative)
548 return -EINVAL;
549 if (_res != (unsigned long)_res)
550 return -ERANGE;
551 *res = _res;
552 return err;
553}
554
555const struct bpf_func_proto bpf_strtoul_proto = {
556 .func = bpf_strtoul,
557 .gpl_only = false,
558 .ret_type = RET_INTEGER,
559 .arg1_type = ARG_PTR_TO_MEM | MEM_RDONLY,
560 .arg2_type = ARG_CONST_SIZE,
561 .arg3_type = ARG_ANYTHING,
562 .arg4_type = ARG_PTR_TO_LONG,
563};
564
565BPF_CALL_3(bpf_strncmp, const char *, s1, u32, s1_sz, const char *, s2)
566{
567 return strncmp(s1, s2, s1_sz);
568}
569
570static const struct bpf_func_proto bpf_strncmp_proto = {
571 .func = bpf_strncmp,
572 .gpl_only = false,
573 .ret_type = RET_INTEGER,
574 .arg1_type = ARG_PTR_TO_MEM,
575 .arg2_type = ARG_CONST_SIZE,
576 .arg3_type = ARG_PTR_TO_CONST_STR,
577};
578
579BPF_CALL_4(bpf_get_ns_current_pid_tgid, u64, dev, u64, ino,
580 struct bpf_pidns_info *, nsdata, u32, size)
581{
582 struct task_struct *task = current;
583 struct pid_namespace *pidns;
584 int err = -EINVAL;
585
586 if (unlikely(size != sizeof(struct bpf_pidns_info)))
587 goto clear;
588
589 if (unlikely((u64)(dev_t)dev != dev))
590 goto clear;
591
592 if (unlikely(!task))
593 goto clear;
594
595 pidns = task_active_pid_ns(task);
596 if (unlikely(!pidns)) {
597 err = -ENOENT;
598 goto clear;
599 }
600
601 if (!ns_match(&pidns->ns, (dev_t)dev, ino))
602 goto clear;
603
604 nsdata->pid = task_pid_nr_ns(task, pidns);
605 nsdata->tgid = task_tgid_nr_ns(task, pidns);
606 return 0;
607clear:
608 memset((void *)nsdata, 0, (size_t) size);
609 return err;
610}
611
612const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto = {
613 .func = bpf_get_ns_current_pid_tgid,
614 .gpl_only = false,
615 .ret_type = RET_INTEGER,
616 .arg1_type = ARG_ANYTHING,
617 .arg2_type = ARG_ANYTHING,
618 .arg3_type = ARG_PTR_TO_UNINIT_MEM,
619 .arg4_type = ARG_CONST_SIZE,
620};
621
622static const struct bpf_func_proto bpf_get_raw_smp_processor_id_proto = {
623 .func = bpf_get_raw_cpu_id,
624 .gpl_only = false,
625 .ret_type = RET_INTEGER,
626};
627
628BPF_CALL_5(bpf_event_output_data, void *, ctx, struct bpf_map *, map,
629 u64, flags, void *, data, u64, size)
630{
631 if (unlikely(flags & ~(BPF_F_INDEX_MASK)))
632 return -EINVAL;
633
634 return bpf_event_output(map, flags, data, size, NULL, 0, NULL);
635}
636
637const struct bpf_func_proto bpf_event_output_data_proto = {
638 .func = bpf_event_output_data,
639 .gpl_only = true,
640 .ret_type = RET_INTEGER,
641 .arg1_type = ARG_PTR_TO_CTX,
642 .arg2_type = ARG_CONST_MAP_PTR,
643 .arg3_type = ARG_ANYTHING,
644 .arg4_type = ARG_PTR_TO_MEM | MEM_RDONLY,
645 .arg5_type = ARG_CONST_SIZE_OR_ZERO,
646};
647
648BPF_CALL_3(bpf_copy_from_user, void *, dst, u32, size,
649 const void __user *, user_ptr)
650{
651 int ret = copy_from_user(dst, user_ptr, size);
652
653 if (unlikely(ret)) {
654 memset(dst, 0, size);
655 ret = -EFAULT;
656 }
657
658 return ret;
659}
660
661const struct bpf_func_proto bpf_copy_from_user_proto = {
662 .func = bpf_copy_from_user,
663 .gpl_only = false,
664 .might_sleep = true,
665 .ret_type = RET_INTEGER,
666 .arg1_type = ARG_PTR_TO_UNINIT_MEM,
667 .arg2_type = ARG_CONST_SIZE_OR_ZERO,
668 .arg3_type = ARG_ANYTHING,
669};
670
671BPF_CALL_5(bpf_copy_from_user_task, void *, dst, u32, size,
672 const void __user *, user_ptr, struct task_struct *, tsk, u64, flags)
673{
674 int ret;
675
676 /* flags is not used yet */
677 if (unlikely(flags))
678 return -EINVAL;
679
680 if (unlikely(!size))
681 return 0;
682
683 ret = access_process_vm(tsk, (unsigned long)user_ptr, dst, size, 0);
684 if (ret == size)
685 return 0;
686
687 memset(dst, 0, size);
688 /* Return -EFAULT for partial read */
689 return ret < 0 ? ret : -EFAULT;
690}
691
692const struct bpf_func_proto bpf_copy_from_user_task_proto = {
693 .func = bpf_copy_from_user_task,
694 .gpl_only = true,
695 .might_sleep = true,
696 .ret_type = RET_INTEGER,
697 .arg1_type = ARG_PTR_TO_UNINIT_MEM,
698 .arg2_type = ARG_CONST_SIZE_OR_ZERO,
699 .arg3_type = ARG_ANYTHING,
700 .arg4_type = ARG_PTR_TO_BTF_ID,
701 .arg4_btf_id = &btf_tracing_ids[BTF_TRACING_TYPE_TASK],
702 .arg5_type = ARG_ANYTHING
703};
704
705BPF_CALL_2(bpf_per_cpu_ptr, const void *, ptr, u32, cpu)
706{
707 if (cpu >= nr_cpu_ids)
708 return (unsigned long)NULL;
709
710 return (unsigned long)per_cpu_ptr((const void __percpu *)ptr, cpu);
711}
712
713const struct bpf_func_proto bpf_per_cpu_ptr_proto = {
714 .func = bpf_per_cpu_ptr,
715 .gpl_only = false,
716 .ret_type = RET_PTR_TO_MEM_OR_BTF_ID | PTR_MAYBE_NULL | MEM_RDONLY,
717 .arg1_type = ARG_PTR_TO_PERCPU_BTF_ID,
718 .arg2_type = ARG_ANYTHING,
719};
720
721BPF_CALL_1(bpf_this_cpu_ptr, const void *, percpu_ptr)
722{
723 return (unsigned long)this_cpu_ptr((const void __percpu *)percpu_ptr);
724}
725
726const struct bpf_func_proto bpf_this_cpu_ptr_proto = {
727 .func = bpf_this_cpu_ptr,
728 .gpl_only = false,
729 .ret_type = RET_PTR_TO_MEM_OR_BTF_ID | MEM_RDONLY,
730 .arg1_type = ARG_PTR_TO_PERCPU_BTF_ID,
731};
732
733static int bpf_trace_copy_string(char *buf, void *unsafe_ptr, char fmt_ptype,
734 size_t bufsz)
735{
736 void __user *user_ptr = (__force void __user *)unsafe_ptr;
737
738 buf[0] = 0;
739
740 switch (fmt_ptype) {
741 case 's':
742#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
743 if ((unsigned long)unsafe_ptr < TASK_SIZE)
744 return strncpy_from_user_nofault(buf, user_ptr, bufsz);
745 fallthrough;
746#endif
747 case 'k':
748 return strncpy_from_kernel_nofault(buf, unsafe_ptr, bufsz);
749 case 'u':
750 return strncpy_from_user_nofault(buf, user_ptr, bufsz);
751 }
752
753 return -EINVAL;
754}
755
756/* Per-cpu temp buffers used by printf-like helpers to store the bprintf binary
757 * arguments representation.
758 */
759#define MAX_BPRINTF_BUF_LEN 512
760
761/* Support executing three nested bprintf helper calls on a given CPU */
762#define MAX_BPRINTF_NEST_LEVEL 3
763struct bpf_bprintf_buffers {
764 char tmp_bufs[MAX_BPRINTF_NEST_LEVEL][MAX_BPRINTF_BUF_LEN];
765};
766static DEFINE_PER_CPU(struct bpf_bprintf_buffers, bpf_bprintf_bufs);
767static DEFINE_PER_CPU(int, bpf_bprintf_nest_level);
768
769static int try_get_fmt_tmp_buf(char **tmp_buf)
770{
771 struct bpf_bprintf_buffers *bufs;
772 int nest_level;
773
774 preempt_disable();
775 nest_level = this_cpu_inc_return(bpf_bprintf_nest_level);
776 if (WARN_ON_ONCE(nest_level > MAX_BPRINTF_NEST_LEVEL)) {
777 this_cpu_dec(bpf_bprintf_nest_level);
778 preempt_enable();
779 return -EBUSY;
780 }
781 bufs = this_cpu_ptr(&bpf_bprintf_bufs);
782 *tmp_buf = bufs->tmp_bufs[nest_level - 1];
783
784 return 0;
785}
786
787void bpf_bprintf_cleanup(void)
788{
789 if (this_cpu_read(bpf_bprintf_nest_level)) {
790 this_cpu_dec(bpf_bprintf_nest_level);
791 preempt_enable();
792 }
793}
794
795/*
796 * bpf_bprintf_prepare - Generic pass on format strings for bprintf-like helpers
797 *
798 * Returns a negative value if fmt is an invalid format string or 0 otherwise.
799 *
800 * This can be used in two ways:
801 * - Format string verification only: when bin_args is NULL
802 * - Arguments preparation: in addition to the above verification, it writes in
803 * bin_args a binary representation of arguments usable by bstr_printf where
804 * pointers from BPF have been sanitized.
805 *
806 * In argument preparation mode, if 0 is returned, safe temporary buffers are
807 * allocated and bpf_bprintf_cleanup should be called to free them after use.
808 */
809int bpf_bprintf_prepare(char *fmt, u32 fmt_size, const u64 *raw_args,
810 u32 **bin_args, u32 num_args)
811{
812 char *unsafe_ptr = NULL, *tmp_buf = NULL, *tmp_buf_end, *fmt_end;
813 size_t sizeof_cur_arg, sizeof_cur_ip;
814 int err, i, num_spec = 0;
815 u64 cur_arg;
816 char fmt_ptype, cur_ip[16], ip_spec[] = "%pXX";
817
818 fmt_end = strnchr(fmt, fmt_size, 0);
819 if (!fmt_end)
820 return -EINVAL;
821 fmt_size = fmt_end - fmt;
822
823 if (bin_args) {
824 if (num_args && try_get_fmt_tmp_buf(&tmp_buf))
825 return -EBUSY;
826
827 tmp_buf_end = tmp_buf + MAX_BPRINTF_BUF_LEN;
828 *bin_args = (u32 *)tmp_buf;
829 }
830
831 for (i = 0; i < fmt_size; i++) {
832 if ((!isprint(fmt[i]) && !isspace(fmt[i])) || !isascii(fmt[i])) {
833 err = -EINVAL;
834 goto out;
835 }
836
837 if (fmt[i] != '%')
838 continue;
839
840 if (fmt[i + 1] == '%') {
841 i++;
842 continue;
843 }
844
845 if (num_spec >= num_args) {
846 err = -EINVAL;
847 goto out;
848 }
849
850 /* The string is zero-terminated so if fmt[i] != 0, we can
851 * always access fmt[i + 1], in the worst case it will be a 0
852 */
853 i++;
854
855 /* skip optional "[0 +-][num]" width formatting field */
856 while (fmt[i] == '0' || fmt[i] == '+' || fmt[i] == '-' ||
857 fmt[i] == ' ')
858 i++;
859 if (fmt[i] >= '1' && fmt[i] <= '9') {
860 i++;
861 while (fmt[i] >= '0' && fmt[i] <= '9')
862 i++;
863 }
864
865 if (fmt[i] == 'p') {
866 sizeof_cur_arg = sizeof(long);
867
868 if ((fmt[i + 1] == 'k' || fmt[i + 1] == 'u') &&
869 fmt[i + 2] == 's') {
870 fmt_ptype = fmt[i + 1];
871 i += 2;
872 goto fmt_str;
873 }
874
875 if (fmt[i + 1] == 0 || isspace(fmt[i + 1]) ||
876 ispunct(fmt[i + 1]) || fmt[i + 1] == 'K' ||
877 fmt[i + 1] == 'x' || fmt[i + 1] == 's' ||
878 fmt[i + 1] == 'S') {
879 /* just kernel pointers */
880 if (tmp_buf)
881 cur_arg = raw_args[num_spec];
882 i++;
883 goto nocopy_fmt;
884 }
885
886 if (fmt[i + 1] == 'B') {
887 if (tmp_buf) {
888 err = snprintf(tmp_buf,
889 (tmp_buf_end - tmp_buf),
890 "%pB",
891 (void *)(long)raw_args[num_spec]);
892 tmp_buf += (err + 1);
893 }
894
895 i++;
896 num_spec++;
897 continue;
898 }
899
900 /* only support "%pI4", "%pi4", "%pI6" and "%pi6". */
901 if ((fmt[i + 1] != 'i' && fmt[i + 1] != 'I') ||
902 (fmt[i + 2] != '4' && fmt[i + 2] != '6')) {
903 err = -EINVAL;
904 goto out;
905 }
906
907 i += 2;
908 if (!tmp_buf)
909 goto nocopy_fmt;
910
911 sizeof_cur_ip = (fmt[i] == '4') ? 4 : 16;
912 if (tmp_buf_end - tmp_buf < sizeof_cur_ip) {
913 err = -ENOSPC;
914 goto out;
915 }
916
917 unsafe_ptr = (char *)(long)raw_args[num_spec];
918 err = copy_from_kernel_nofault(cur_ip, unsafe_ptr,
919 sizeof_cur_ip);
920 if (err < 0)
921 memset(cur_ip, 0, sizeof_cur_ip);
922
923 /* hack: bstr_printf expects IP addresses to be
924 * pre-formatted as strings, ironically, the easiest way
925 * to do that is to call snprintf.
926 */
927 ip_spec[2] = fmt[i - 1];
928 ip_spec[3] = fmt[i];
929 err = snprintf(tmp_buf, tmp_buf_end - tmp_buf,
930 ip_spec, &cur_ip);
931
932 tmp_buf += err + 1;
933 num_spec++;
934
935 continue;
936 } else if (fmt[i] == 's') {
937 fmt_ptype = fmt[i];
938fmt_str:
939 if (fmt[i + 1] != 0 &&
940 !isspace(fmt[i + 1]) &&
941 !ispunct(fmt[i + 1])) {
942 err = -EINVAL;
943 goto out;
944 }
945
946 if (!tmp_buf)
947 goto nocopy_fmt;
948
949 if (tmp_buf_end == tmp_buf) {
950 err = -ENOSPC;
951 goto out;
952 }
953
954 unsafe_ptr = (char *)(long)raw_args[num_spec];
955 err = bpf_trace_copy_string(tmp_buf, unsafe_ptr,
956 fmt_ptype,
957 tmp_buf_end - tmp_buf);
958 if (err < 0) {
959 tmp_buf[0] = '\0';
960 err = 1;
961 }
962
963 tmp_buf += err;
964 num_spec++;
965
966 continue;
967 } else if (fmt[i] == 'c') {
968 if (!tmp_buf)
969 goto nocopy_fmt;
970
971 if (tmp_buf_end == tmp_buf) {
972 err = -ENOSPC;
973 goto out;
974 }
975
976 *tmp_buf = raw_args[num_spec];
977 tmp_buf++;
978 num_spec++;
979
980 continue;
981 }
982
983 sizeof_cur_arg = sizeof(int);
984
985 if (fmt[i] == 'l') {
986 sizeof_cur_arg = sizeof(long);
987 i++;
988 }
989 if (fmt[i] == 'l') {
990 sizeof_cur_arg = sizeof(long long);
991 i++;
992 }
993
994 if (fmt[i] != 'i' && fmt[i] != 'd' && fmt[i] != 'u' &&
995 fmt[i] != 'x' && fmt[i] != 'X') {
996 err = -EINVAL;
997 goto out;
998 }
999
1000 if (tmp_buf)
1001 cur_arg = raw_args[num_spec];
1002nocopy_fmt:
1003 if (tmp_buf) {
1004 tmp_buf = PTR_ALIGN(tmp_buf, sizeof(u32));
1005 if (tmp_buf_end - tmp_buf < sizeof_cur_arg) {
1006 err = -ENOSPC;
1007 goto out;
1008 }
1009
1010 if (sizeof_cur_arg == 8) {
1011 *(u32 *)tmp_buf = *(u32 *)&cur_arg;
1012 *(u32 *)(tmp_buf + 4) = *((u32 *)&cur_arg + 1);
1013 } else {
1014 *(u32 *)tmp_buf = (u32)(long)cur_arg;
1015 }
1016 tmp_buf += sizeof_cur_arg;
1017 }
1018 num_spec++;
1019 }
1020
1021 err = 0;
1022out:
1023 if (err)
1024 bpf_bprintf_cleanup();
1025 return err;
1026}
1027
1028BPF_CALL_5(bpf_snprintf, char *, str, u32, str_size, char *, fmt,
1029 const void *, data, u32, data_len)
1030{
1031 int err, num_args;
1032 u32 *bin_args;
1033
1034 if (data_len % 8 || data_len > MAX_BPRINTF_VARARGS * 8 ||
1035 (data_len && !data))
1036 return -EINVAL;
1037 num_args = data_len / 8;
1038
1039 /* ARG_PTR_TO_CONST_STR guarantees that fmt is zero-terminated so we
1040 * can safely give an unbounded size.
1041 */
1042 err = bpf_bprintf_prepare(fmt, UINT_MAX, data, &bin_args, num_args);
1043 if (err < 0)
1044 return err;
1045
1046 err = bstr_printf(str, str_size, fmt, bin_args);
1047
1048 bpf_bprintf_cleanup();
1049
1050 return err + 1;
1051}
1052
1053const struct bpf_func_proto bpf_snprintf_proto = {
1054 .func = bpf_snprintf,
1055 .gpl_only = true,
1056 .ret_type = RET_INTEGER,
1057 .arg1_type = ARG_PTR_TO_MEM_OR_NULL,
1058 .arg2_type = ARG_CONST_SIZE_OR_ZERO,
1059 .arg3_type = ARG_PTR_TO_CONST_STR,
1060 .arg4_type = ARG_PTR_TO_MEM | PTR_MAYBE_NULL | MEM_RDONLY,
1061 .arg5_type = ARG_CONST_SIZE_OR_ZERO,
1062};
1063
1064/* BPF map elements can contain 'struct bpf_timer'.
1065 * Such map owns all of its BPF timers.
1066 * 'struct bpf_timer' is allocated as part of map element allocation
1067 * and it's zero initialized.
1068 * That space is used to keep 'struct bpf_timer_kern'.
1069 * bpf_timer_init() allocates 'struct bpf_hrtimer', inits hrtimer, and
1070 * remembers 'struct bpf_map *' pointer it's part of.
1071 * bpf_timer_set_callback() increments prog refcnt and assign bpf callback_fn.
1072 * bpf_timer_start() arms the timer.
1073 * If user space reference to a map goes to zero at this point
1074 * ops->map_release_uref callback is responsible for cancelling the timers,
1075 * freeing their memory, and decrementing prog's refcnts.
1076 * bpf_timer_cancel() cancels the timer and decrements prog's refcnt.
1077 * Inner maps can contain bpf timers as well. ops->map_release_uref is
1078 * freeing the timers when inner map is replaced or deleted by user space.
1079 */
1080struct bpf_hrtimer {
1081 struct hrtimer timer;
1082 struct bpf_map *map;
1083 struct bpf_prog *prog;
1084 void __rcu *callback_fn;
1085 void *value;
1086};
1087
1088/* the actual struct hidden inside uapi struct bpf_timer */
1089struct bpf_timer_kern {
1090 struct bpf_hrtimer *timer;
1091 /* bpf_spin_lock is used here instead of spinlock_t to make
1092 * sure that it always fits into space reserved by struct bpf_timer
1093 * regardless of LOCKDEP and spinlock debug flags.
1094 */
1095 struct bpf_spin_lock lock;
1096} __attribute__((aligned(8)));
1097
1098static DEFINE_PER_CPU(struct bpf_hrtimer *, hrtimer_running);
1099
1100static enum hrtimer_restart bpf_timer_cb(struct hrtimer *hrtimer)
1101{
1102 struct bpf_hrtimer *t = container_of(hrtimer, struct bpf_hrtimer, timer);
1103 struct bpf_map *map = t->map;
1104 void *value = t->value;
1105 bpf_callback_t callback_fn;
1106 void *key;
1107 u32 idx;
1108
1109 BTF_TYPE_EMIT(struct bpf_timer);
1110 callback_fn = rcu_dereference_check(t->callback_fn, rcu_read_lock_bh_held());
1111 if (!callback_fn)
1112 goto out;
1113
1114 /* bpf_timer_cb() runs in hrtimer_run_softirq. It doesn't migrate and
1115 * cannot be preempted by another bpf_timer_cb() on the same cpu.
1116 * Remember the timer this callback is servicing to prevent
1117 * deadlock if callback_fn() calls bpf_timer_cancel() or
1118 * bpf_map_delete_elem() on the same timer.
1119 */
1120 this_cpu_write(hrtimer_running, t);
1121 if (map->map_type == BPF_MAP_TYPE_ARRAY) {
1122 struct bpf_array *array = container_of(map, struct bpf_array, map);
1123
1124 /* compute the key */
1125 idx = ((char *)value - array->value) / array->elem_size;
1126 key = &idx;
1127 } else { /* hash or lru */
1128 key = value - round_up(map->key_size, 8);
1129 }
1130
1131 callback_fn((u64)(long)map, (u64)(long)key, (u64)(long)value, 0, 0);
1132 /* The verifier checked that return value is zero. */
1133
1134 this_cpu_write(hrtimer_running, NULL);
1135out:
1136 return HRTIMER_NORESTART;
1137}
1138
1139BPF_CALL_3(bpf_timer_init, struct bpf_timer_kern *, timer, struct bpf_map *, map,
1140 u64, flags)
1141{
1142 clockid_t clockid = flags & (MAX_CLOCKS - 1);
1143 struct bpf_hrtimer *t;
1144 int ret = 0;
1145
1146 BUILD_BUG_ON(MAX_CLOCKS != 16);
1147 BUILD_BUG_ON(sizeof(struct bpf_timer_kern) > sizeof(struct bpf_timer));
1148 BUILD_BUG_ON(__alignof__(struct bpf_timer_kern) != __alignof__(struct bpf_timer));
1149
1150 if (in_nmi())
1151 return -EOPNOTSUPP;
1152
1153 if (flags >= MAX_CLOCKS ||
1154 /* similar to timerfd except _ALARM variants are not supported */
1155 (clockid != CLOCK_MONOTONIC &&
1156 clockid != CLOCK_REALTIME &&
1157 clockid != CLOCK_BOOTTIME))
1158 return -EINVAL;
1159 __bpf_spin_lock_irqsave(&timer->lock);
1160 t = timer->timer;
1161 if (t) {
1162 ret = -EBUSY;
1163 goto out;
1164 }
1165 if (!atomic64_read(&map->usercnt)) {
1166 /* maps with timers must be either held by user space
1167 * or pinned in bpffs.
1168 */
1169 ret = -EPERM;
1170 goto out;
1171 }
1172 /* allocate hrtimer via map_kmalloc to use memcg accounting */
1173 t = bpf_map_kmalloc_node(map, sizeof(*t), GFP_ATOMIC, map->numa_node);
1174 if (!t) {
1175 ret = -ENOMEM;
1176 goto out;
1177 }
1178 t->value = (void *)timer - map->record->timer_off;
1179 t->map = map;
1180 t->prog = NULL;
1181 rcu_assign_pointer(t->callback_fn, NULL);
1182 hrtimer_init(&t->timer, clockid, HRTIMER_MODE_REL_SOFT);
1183 t->timer.function = bpf_timer_cb;
1184 timer->timer = t;
1185out:
1186 __bpf_spin_unlock_irqrestore(&timer->lock);
1187 return ret;
1188}
1189
1190static const struct bpf_func_proto bpf_timer_init_proto = {
1191 .func = bpf_timer_init,
1192 .gpl_only = true,
1193 .ret_type = RET_INTEGER,
1194 .arg1_type = ARG_PTR_TO_TIMER,
1195 .arg2_type = ARG_CONST_MAP_PTR,
1196 .arg3_type = ARG_ANYTHING,
1197};
1198
1199BPF_CALL_3(bpf_timer_set_callback, struct bpf_timer_kern *, timer, void *, callback_fn,
1200 struct bpf_prog_aux *, aux)
1201{
1202 struct bpf_prog *prev, *prog = aux->prog;
1203 struct bpf_hrtimer *t;
1204 int ret = 0;
1205
1206 if (in_nmi())
1207 return -EOPNOTSUPP;
1208 __bpf_spin_lock_irqsave(&timer->lock);
1209 t = timer->timer;
1210 if (!t) {
1211 ret = -EINVAL;
1212 goto out;
1213 }
1214 if (!atomic64_read(&t->map->usercnt)) {
1215 /* maps with timers must be either held by user space
1216 * or pinned in bpffs. Otherwise timer might still be
1217 * running even when bpf prog is detached and user space
1218 * is gone, since map_release_uref won't ever be called.
1219 */
1220 ret = -EPERM;
1221 goto out;
1222 }
1223 prev = t->prog;
1224 if (prev != prog) {
1225 /* Bump prog refcnt once. Every bpf_timer_set_callback()
1226 * can pick different callback_fn-s within the same prog.
1227 */
1228 prog = bpf_prog_inc_not_zero(prog);
1229 if (IS_ERR(prog)) {
1230 ret = PTR_ERR(prog);
1231 goto out;
1232 }
1233 if (prev)
1234 /* Drop prev prog refcnt when swapping with new prog */
1235 bpf_prog_put(prev);
1236 t->prog = prog;
1237 }
1238 rcu_assign_pointer(t->callback_fn, callback_fn);
1239out:
1240 __bpf_spin_unlock_irqrestore(&timer->lock);
1241 return ret;
1242}
1243
1244static const struct bpf_func_proto bpf_timer_set_callback_proto = {
1245 .func = bpf_timer_set_callback,
1246 .gpl_only = true,
1247 .ret_type = RET_INTEGER,
1248 .arg1_type = ARG_PTR_TO_TIMER,
1249 .arg2_type = ARG_PTR_TO_FUNC,
1250};
1251
1252BPF_CALL_3(bpf_timer_start, struct bpf_timer_kern *, timer, u64, nsecs, u64, flags)
1253{
1254 struct bpf_hrtimer *t;
1255 int ret = 0;
1256
1257 if (in_nmi())
1258 return -EOPNOTSUPP;
1259 if (flags)
1260 return -EINVAL;
1261 __bpf_spin_lock_irqsave(&timer->lock);
1262 t = timer->timer;
1263 if (!t || !t->prog) {
1264 ret = -EINVAL;
1265 goto out;
1266 }
1267 hrtimer_start(&t->timer, ns_to_ktime(nsecs), HRTIMER_MODE_REL_SOFT);
1268out:
1269 __bpf_spin_unlock_irqrestore(&timer->lock);
1270 return ret;
1271}
1272
1273static const struct bpf_func_proto bpf_timer_start_proto = {
1274 .func = bpf_timer_start,
1275 .gpl_only = true,
1276 .ret_type = RET_INTEGER,
1277 .arg1_type = ARG_PTR_TO_TIMER,
1278 .arg2_type = ARG_ANYTHING,
1279 .arg3_type = ARG_ANYTHING,
1280};
1281
1282static void drop_prog_refcnt(struct bpf_hrtimer *t)
1283{
1284 struct bpf_prog *prog = t->prog;
1285
1286 if (prog) {
1287 bpf_prog_put(prog);
1288 t->prog = NULL;
1289 rcu_assign_pointer(t->callback_fn, NULL);
1290 }
1291}
1292
1293BPF_CALL_1(bpf_timer_cancel, struct bpf_timer_kern *, timer)
1294{
1295 struct bpf_hrtimer *t;
1296 int ret = 0;
1297
1298 if (in_nmi())
1299 return -EOPNOTSUPP;
1300 __bpf_spin_lock_irqsave(&timer->lock);
1301 t = timer->timer;
1302 if (!t) {
1303 ret = -EINVAL;
1304 goto out;
1305 }
1306 if (this_cpu_read(hrtimer_running) == t) {
1307 /* If bpf callback_fn is trying to bpf_timer_cancel()
1308 * its own timer the hrtimer_cancel() will deadlock
1309 * since it waits for callback_fn to finish
1310 */
1311 ret = -EDEADLK;
1312 goto out;
1313 }
1314 drop_prog_refcnt(t);
1315out:
1316 __bpf_spin_unlock_irqrestore(&timer->lock);
1317 /* Cancel the timer and wait for associated callback to finish
1318 * if it was running.
1319 */
1320 ret = ret ?: hrtimer_cancel(&t->timer);
1321 return ret;
1322}
1323
1324static const struct bpf_func_proto bpf_timer_cancel_proto = {
1325 .func = bpf_timer_cancel,
1326 .gpl_only = true,
1327 .ret_type = RET_INTEGER,
1328 .arg1_type = ARG_PTR_TO_TIMER,
1329};
1330
1331/* This function is called by map_delete/update_elem for individual element and
1332 * by ops->map_release_uref when the user space reference to a map reaches zero.
1333 */
1334void bpf_timer_cancel_and_free(void *val)
1335{
1336 struct bpf_timer_kern *timer = val;
1337 struct bpf_hrtimer *t;
1338
1339 /* Performance optimization: read timer->timer without lock first. */
1340 if (!READ_ONCE(timer->timer))
1341 return;
1342
1343 __bpf_spin_lock_irqsave(&timer->lock);
1344 /* re-read it under lock */
1345 t = timer->timer;
1346 if (!t)
1347 goto out;
1348 drop_prog_refcnt(t);
1349 /* The subsequent bpf_timer_start/cancel() helpers won't be able to use
1350 * this timer, since it won't be initialized.
1351 */
1352 timer->timer = NULL;
1353out:
1354 __bpf_spin_unlock_irqrestore(&timer->lock);
1355 if (!t)
1356 return;
1357 /* Cancel the timer and wait for callback to complete if it was running.
1358 * If hrtimer_cancel() can be safely called it's safe to call kfree(t)
1359 * right after for both preallocated and non-preallocated maps.
1360 * The timer->timer = NULL was already done and no code path can
1361 * see address 't' anymore.
1362 *
1363 * Check that bpf_map_delete/update_elem() wasn't called from timer
1364 * callback_fn. In such case don't call hrtimer_cancel() (since it will
1365 * deadlock) and don't call hrtimer_try_to_cancel() (since it will just
1366 * return -1). Though callback_fn is still running on this cpu it's
1367 * safe to do kfree(t) because bpf_timer_cb() read everything it needed
1368 * from 't'. The bpf subprog callback_fn won't be able to access 't',
1369 * since timer->timer = NULL was already done. The timer will be
1370 * effectively cancelled because bpf_timer_cb() will return
1371 * HRTIMER_NORESTART.
1372 */
1373 if (this_cpu_read(hrtimer_running) != t)
1374 hrtimer_cancel(&t->timer);
1375 kfree(t);
1376}
1377
1378BPF_CALL_2(bpf_kptr_xchg, void *, map_value, void *, ptr)
1379{
1380 unsigned long *kptr = map_value;
1381
1382 return xchg(kptr, (unsigned long)ptr);
1383}
1384
1385/* Unlike other PTR_TO_BTF_ID helpers the btf_id in bpf_kptr_xchg()
1386 * helper is determined dynamically by the verifier. Use BPF_PTR_POISON to
1387 * denote type that verifier will determine.
1388 */
1389static const struct bpf_func_proto bpf_kptr_xchg_proto = {
1390 .func = bpf_kptr_xchg,
1391 .gpl_only = false,
1392 .ret_type = RET_PTR_TO_BTF_ID_OR_NULL,
1393 .ret_btf_id = BPF_PTR_POISON,
1394 .arg1_type = ARG_PTR_TO_KPTR,
1395 .arg2_type = ARG_PTR_TO_BTF_ID_OR_NULL | OBJ_RELEASE,
1396 .arg2_btf_id = BPF_PTR_POISON,
1397};
1398
1399/* Since the upper 8 bits of dynptr->size is reserved, the
1400 * maximum supported size is 2^24 - 1.
1401 */
1402#define DYNPTR_MAX_SIZE ((1UL << 24) - 1)
1403#define DYNPTR_TYPE_SHIFT 28
1404#define DYNPTR_SIZE_MASK 0xFFFFFF
1405#define DYNPTR_RDONLY_BIT BIT(31)
1406
1407static bool bpf_dynptr_is_rdonly(const struct bpf_dynptr_kern *ptr)
1408{
1409 return ptr->size & DYNPTR_RDONLY_BIT;
1410}
1411
1412static void bpf_dynptr_set_type(struct bpf_dynptr_kern *ptr, enum bpf_dynptr_type type)
1413{
1414 ptr->size |= type << DYNPTR_TYPE_SHIFT;
1415}
1416
1417u32 bpf_dynptr_get_size(const struct bpf_dynptr_kern *ptr)
1418{
1419 return ptr->size & DYNPTR_SIZE_MASK;
1420}
1421
1422int bpf_dynptr_check_size(u32 size)
1423{
1424 return size > DYNPTR_MAX_SIZE ? -E2BIG : 0;
1425}
1426
1427void bpf_dynptr_init(struct bpf_dynptr_kern *ptr, void *data,
1428 enum bpf_dynptr_type type, u32 offset, u32 size)
1429{
1430 ptr->data = data;
1431 ptr->offset = offset;
1432 ptr->size = size;
1433 bpf_dynptr_set_type(ptr, type);
1434}
1435
1436void bpf_dynptr_set_null(struct bpf_dynptr_kern *ptr)
1437{
1438 memset(ptr, 0, sizeof(*ptr));
1439}
1440
1441static int bpf_dynptr_check_off_len(const struct bpf_dynptr_kern *ptr, u32 offset, u32 len)
1442{
1443 u32 size = bpf_dynptr_get_size(ptr);
1444
1445 if (len > size || offset > size - len)
1446 return -E2BIG;
1447
1448 return 0;
1449}
1450
1451BPF_CALL_4(bpf_dynptr_from_mem, void *, data, u32, size, u64, flags, struct bpf_dynptr_kern *, ptr)
1452{
1453 int err;
1454
1455 BTF_TYPE_EMIT(struct bpf_dynptr);
1456
1457 err = bpf_dynptr_check_size(size);
1458 if (err)
1459 goto error;
1460
1461 /* flags is currently unsupported */
1462 if (flags) {
1463 err = -EINVAL;
1464 goto error;
1465 }
1466
1467 bpf_dynptr_init(ptr, data, BPF_DYNPTR_TYPE_LOCAL, 0, size);
1468
1469 return 0;
1470
1471error:
1472 bpf_dynptr_set_null(ptr);
1473 return err;
1474}
1475
1476static const struct bpf_func_proto bpf_dynptr_from_mem_proto = {
1477 .func = bpf_dynptr_from_mem,
1478 .gpl_only = false,
1479 .ret_type = RET_INTEGER,
1480 .arg1_type = ARG_PTR_TO_UNINIT_MEM,
1481 .arg2_type = ARG_CONST_SIZE_OR_ZERO,
1482 .arg3_type = ARG_ANYTHING,
1483 .arg4_type = ARG_PTR_TO_DYNPTR | DYNPTR_TYPE_LOCAL | MEM_UNINIT,
1484};
1485
1486BPF_CALL_5(bpf_dynptr_read, void *, dst, u32, len, const struct bpf_dynptr_kern *, src,
1487 u32, offset, u64, flags)
1488{
1489 int err;
1490
1491 if (!src->data || flags)
1492 return -EINVAL;
1493
1494 err = bpf_dynptr_check_off_len(src, offset, len);
1495 if (err)
1496 return err;
1497
1498 /* Source and destination may possibly overlap, hence use memmove to
1499 * copy the data. E.g. bpf_dynptr_from_mem may create two dynptr
1500 * pointing to overlapping PTR_TO_MAP_VALUE regions.
1501 */
1502 memmove(dst, src->data + src->offset + offset, len);
1503
1504 return 0;
1505}
1506
1507static const struct bpf_func_proto bpf_dynptr_read_proto = {
1508 .func = bpf_dynptr_read,
1509 .gpl_only = false,
1510 .ret_type = RET_INTEGER,
1511 .arg1_type = ARG_PTR_TO_UNINIT_MEM,
1512 .arg2_type = ARG_CONST_SIZE_OR_ZERO,
1513 .arg3_type = ARG_PTR_TO_DYNPTR | MEM_RDONLY,
1514 .arg4_type = ARG_ANYTHING,
1515 .arg5_type = ARG_ANYTHING,
1516};
1517
1518BPF_CALL_5(bpf_dynptr_write, const struct bpf_dynptr_kern *, dst, u32, offset, void *, src,
1519 u32, len, u64, flags)
1520{
1521 int err;
1522
1523 if (!dst->data || flags || bpf_dynptr_is_rdonly(dst))
1524 return -EINVAL;
1525
1526 err = bpf_dynptr_check_off_len(dst, offset, len);
1527 if (err)
1528 return err;
1529
1530 /* Source and destination may possibly overlap, hence use memmove to
1531 * copy the data. E.g. bpf_dynptr_from_mem may create two dynptr
1532 * pointing to overlapping PTR_TO_MAP_VALUE regions.
1533 */
1534 memmove(dst->data + dst->offset + offset, src, len);
1535
1536 return 0;
1537}
1538
1539static const struct bpf_func_proto bpf_dynptr_write_proto = {
1540 .func = bpf_dynptr_write,
1541 .gpl_only = false,
1542 .ret_type = RET_INTEGER,
1543 .arg1_type = ARG_PTR_TO_DYNPTR | MEM_RDONLY,
1544 .arg2_type = ARG_ANYTHING,
1545 .arg3_type = ARG_PTR_TO_MEM | MEM_RDONLY,
1546 .arg4_type = ARG_CONST_SIZE_OR_ZERO,
1547 .arg5_type = ARG_ANYTHING,
1548};
1549
1550BPF_CALL_3(bpf_dynptr_data, const struct bpf_dynptr_kern *, ptr, u32, offset, u32, len)
1551{
1552 int err;
1553
1554 if (!ptr->data)
1555 return 0;
1556
1557 err = bpf_dynptr_check_off_len(ptr, offset, len);
1558 if (err)
1559 return 0;
1560
1561 if (bpf_dynptr_is_rdonly(ptr))
1562 return 0;
1563
1564 return (unsigned long)(ptr->data + ptr->offset + offset);
1565}
1566
1567static const struct bpf_func_proto bpf_dynptr_data_proto = {
1568 .func = bpf_dynptr_data,
1569 .gpl_only = false,
1570 .ret_type = RET_PTR_TO_DYNPTR_MEM_OR_NULL,
1571 .arg1_type = ARG_PTR_TO_DYNPTR | MEM_RDONLY,
1572 .arg2_type = ARG_ANYTHING,
1573 .arg3_type = ARG_CONST_ALLOC_SIZE_OR_ZERO,
1574};
1575
1576const struct bpf_func_proto bpf_get_current_task_proto __weak;
1577const struct bpf_func_proto bpf_get_current_task_btf_proto __weak;
1578const struct bpf_func_proto bpf_probe_read_user_proto __weak;
1579const struct bpf_func_proto bpf_probe_read_user_str_proto __weak;
1580const struct bpf_func_proto bpf_probe_read_kernel_proto __weak;
1581const struct bpf_func_proto bpf_probe_read_kernel_str_proto __weak;
1582const struct bpf_func_proto bpf_task_pt_regs_proto __weak;
1583
1584const struct bpf_func_proto *
1585bpf_base_func_proto(enum bpf_func_id func_id)
1586{
1587 switch (func_id) {
1588 case BPF_FUNC_map_lookup_elem:
1589 return &bpf_map_lookup_elem_proto;
1590 case BPF_FUNC_map_update_elem:
1591 return &bpf_map_update_elem_proto;
1592 case BPF_FUNC_map_delete_elem:
1593 return &bpf_map_delete_elem_proto;
1594 case BPF_FUNC_map_push_elem:
1595 return &bpf_map_push_elem_proto;
1596 case BPF_FUNC_map_pop_elem:
1597 return &bpf_map_pop_elem_proto;
1598 case BPF_FUNC_map_peek_elem:
1599 return &bpf_map_peek_elem_proto;
1600 case BPF_FUNC_map_lookup_percpu_elem:
1601 return &bpf_map_lookup_percpu_elem_proto;
1602 case BPF_FUNC_get_prandom_u32:
1603 return &bpf_get_prandom_u32_proto;
1604 case BPF_FUNC_get_smp_processor_id:
1605 return &bpf_get_raw_smp_processor_id_proto;
1606 case BPF_FUNC_get_numa_node_id:
1607 return &bpf_get_numa_node_id_proto;
1608 case BPF_FUNC_tail_call:
1609 return &bpf_tail_call_proto;
1610 case BPF_FUNC_ktime_get_ns:
1611 return &bpf_ktime_get_ns_proto;
1612 case BPF_FUNC_ktime_get_boot_ns:
1613 return &bpf_ktime_get_boot_ns_proto;
1614 case BPF_FUNC_ktime_get_tai_ns:
1615 return &bpf_ktime_get_tai_ns_proto;
1616 case BPF_FUNC_ringbuf_output:
1617 return &bpf_ringbuf_output_proto;
1618 case BPF_FUNC_ringbuf_reserve:
1619 return &bpf_ringbuf_reserve_proto;
1620 case BPF_FUNC_ringbuf_submit:
1621 return &bpf_ringbuf_submit_proto;
1622 case BPF_FUNC_ringbuf_discard:
1623 return &bpf_ringbuf_discard_proto;
1624 case BPF_FUNC_ringbuf_query:
1625 return &bpf_ringbuf_query_proto;
1626 case BPF_FUNC_strncmp:
1627 return &bpf_strncmp_proto;
1628 case BPF_FUNC_strtol:
1629 return &bpf_strtol_proto;
1630 case BPF_FUNC_strtoul:
1631 return &bpf_strtoul_proto;
1632 default:
1633 break;
1634 }
1635
1636 if (!bpf_capable())
1637 return NULL;
1638
1639 switch (func_id) {
1640 case BPF_FUNC_spin_lock:
1641 return &bpf_spin_lock_proto;
1642 case BPF_FUNC_spin_unlock:
1643 return &bpf_spin_unlock_proto;
1644 case BPF_FUNC_jiffies64:
1645 return &bpf_jiffies64_proto;
1646 case BPF_FUNC_per_cpu_ptr:
1647 return &bpf_per_cpu_ptr_proto;
1648 case BPF_FUNC_this_cpu_ptr:
1649 return &bpf_this_cpu_ptr_proto;
1650 case BPF_FUNC_timer_init:
1651 return &bpf_timer_init_proto;
1652 case BPF_FUNC_timer_set_callback:
1653 return &bpf_timer_set_callback_proto;
1654 case BPF_FUNC_timer_start:
1655 return &bpf_timer_start_proto;
1656 case BPF_FUNC_timer_cancel:
1657 return &bpf_timer_cancel_proto;
1658 case BPF_FUNC_kptr_xchg:
1659 return &bpf_kptr_xchg_proto;
1660 case BPF_FUNC_for_each_map_elem:
1661 return &bpf_for_each_map_elem_proto;
1662 case BPF_FUNC_loop:
1663 return &bpf_loop_proto;
1664 case BPF_FUNC_user_ringbuf_drain:
1665 return &bpf_user_ringbuf_drain_proto;
1666 case BPF_FUNC_ringbuf_reserve_dynptr:
1667 return &bpf_ringbuf_reserve_dynptr_proto;
1668 case BPF_FUNC_ringbuf_submit_dynptr:
1669 return &bpf_ringbuf_submit_dynptr_proto;
1670 case BPF_FUNC_ringbuf_discard_dynptr:
1671 return &bpf_ringbuf_discard_dynptr_proto;
1672 case BPF_FUNC_dynptr_from_mem:
1673 return &bpf_dynptr_from_mem_proto;
1674 case BPF_FUNC_dynptr_read:
1675 return &bpf_dynptr_read_proto;
1676 case BPF_FUNC_dynptr_write:
1677 return &bpf_dynptr_write_proto;
1678 case BPF_FUNC_dynptr_data:
1679 return &bpf_dynptr_data_proto;
1680#ifdef CONFIG_CGROUPS
1681 case BPF_FUNC_cgrp_storage_get:
1682 return &bpf_cgrp_storage_get_proto;
1683 case BPF_FUNC_cgrp_storage_delete:
1684 return &bpf_cgrp_storage_delete_proto;
1685#endif
1686 default:
1687 break;
1688 }
1689
1690 if (!perfmon_capable())
1691 return NULL;
1692
1693 switch (func_id) {
1694 case BPF_FUNC_trace_printk:
1695 return bpf_get_trace_printk_proto();
1696 case BPF_FUNC_get_current_task:
1697 return &bpf_get_current_task_proto;
1698 case BPF_FUNC_get_current_task_btf:
1699 return &bpf_get_current_task_btf_proto;
1700 case BPF_FUNC_probe_read_user:
1701 return &bpf_probe_read_user_proto;
1702 case BPF_FUNC_probe_read_kernel:
1703 return security_locked_down(LOCKDOWN_BPF_READ_KERNEL) < 0 ?
1704 NULL : &bpf_probe_read_kernel_proto;
1705 case BPF_FUNC_probe_read_user_str:
1706 return &bpf_probe_read_user_str_proto;
1707 case BPF_FUNC_probe_read_kernel_str:
1708 return security_locked_down(LOCKDOWN_BPF_READ_KERNEL) < 0 ?
1709 NULL : &bpf_probe_read_kernel_str_proto;
1710 case BPF_FUNC_snprintf_btf:
1711 return &bpf_snprintf_btf_proto;
1712 case BPF_FUNC_snprintf:
1713 return &bpf_snprintf_proto;
1714 case BPF_FUNC_task_pt_regs:
1715 return &bpf_task_pt_regs_proto;
1716 case BPF_FUNC_trace_vprintk:
1717 return bpf_get_trace_vprintk_proto();
1718 default:
1719 return NULL;
1720 }
1721}
1722
1723void bpf_list_head_free(const struct btf_field *field, void *list_head,
1724 struct bpf_spin_lock *spin_lock)
1725{
1726 struct list_head *head = list_head, *orig_head = list_head;
1727
1728 BUILD_BUG_ON(sizeof(struct list_head) > sizeof(struct bpf_list_head));
1729 BUILD_BUG_ON(__alignof__(struct list_head) > __alignof__(struct bpf_list_head));
1730
1731 /* Do the actual list draining outside the lock to not hold the lock for
1732 * too long, and also prevent deadlocks if tracing programs end up
1733 * executing on entry/exit of functions called inside the critical
1734 * section, and end up doing map ops that call bpf_list_head_free for
1735 * the same map value again.
1736 */
1737 __bpf_spin_lock_irqsave(spin_lock);
1738 if (!head->next || list_empty(head))
1739 goto unlock;
1740 head = head->next;
1741unlock:
1742 INIT_LIST_HEAD(orig_head);
1743 __bpf_spin_unlock_irqrestore(spin_lock);
1744
1745 while (head != orig_head) {
1746 void *obj = head;
1747
1748 obj -= field->list_head.node_offset;
1749 head = head->next;
1750 /* The contained type can also have resources, including a
1751 * bpf_list_head which needs to be freed.
1752 */
1753 bpf_obj_free_fields(field->list_head.value_rec, obj);
1754 /* bpf_mem_free requires migrate_disable(), since we can be
1755 * called from map free path as well apart from BPF program (as
1756 * part of map ops doing bpf_obj_free_fields).
1757 */
1758 migrate_disable();
1759 bpf_mem_free(&bpf_global_ma, obj);
1760 migrate_enable();
1761 }
1762}
1763
1764__diag_push();
1765__diag_ignore_all("-Wmissing-prototypes",
1766 "Global functions as their definitions will be in vmlinux BTF");
1767
1768void *bpf_obj_new_impl(u64 local_type_id__k, void *meta__ign)
1769{
1770 struct btf_struct_meta *meta = meta__ign;
1771 u64 size = local_type_id__k;
1772 void *p;
1773
1774 p = bpf_mem_alloc(&bpf_global_ma, size);
1775 if (!p)
1776 return NULL;
1777 if (meta)
1778 bpf_obj_init(meta->field_offs, p);
1779 return p;
1780}
1781
1782void bpf_obj_drop_impl(void *p__alloc, void *meta__ign)
1783{
1784 struct btf_struct_meta *meta = meta__ign;
1785 void *p = p__alloc;
1786
1787 if (meta)
1788 bpf_obj_free_fields(meta->record, p);
1789 bpf_mem_free(&bpf_global_ma, p);
1790}
1791
1792static void __bpf_list_add(struct bpf_list_node *node, struct bpf_list_head *head, bool tail)
1793{
1794 struct list_head *n = (void *)node, *h = (void *)head;
1795
1796 if (unlikely(!h->next))
1797 INIT_LIST_HEAD(h);
1798 if (unlikely(!n->next))
1799 INIT_LIST_HEAD(n);
1800 tail ? list_add_tail(n, h) : list_add(n, h);
1801}
1802
1803void bpf_list_push_front(struct bpf_list_head *head, struct bpf_list_node *node)
1804{
1805 return __bpf_list_add(node, head, false);
1806}
1807
1808void bpf_list_push_back(struct bpf_list_head *head, struct bpf_list_node *node)
1809{
1810 return __bpf_list_add(node, head, true);
1811}
1812
1813static struct bpf_list_node *__bpf_list_del(struct bpf_list_head *head, bool tail)
1814{
1815 struct list_head *n, *h = (void *)head;
1816
1817 if (unlikely(!h->next))
1818 INIT_LIST_HEAD(h);
1819 if (list_empty(h))
1820 return NULL;
1821 n = tail ? h->prev : h->next;
1822 list_del_init(n);
1823 return (struct bpf_list_node *)n;
1824}
1825
1826struct bpf_list_node *bpf_list_pop_front(struct bpf_list_head *head)
1827{
1828 return __bpf_list_del(head, false);
1829}
1830
1831struct bpf_list_node *bpf_list_pop_back(struct bpf_list_head *head)
1832{
1833 return __bpf_list_del(head, true);
1834}
1835
1836/**
1837 * bpf_task_acquire - Acquire a reference to a task. A task acquired by this
1838 * kfunc which is not stored in a map as a kptr, must be released by calling
1839 * bpf_task_release().
1840 * @p: The task on which a reference is being acquired.
1841 */
1842struct task_struct *bpf_task_acquire(struct task_struct *p)
1843{
1844 return get_task_struct(p);
1845}
1846
1847/**
1848 * bpf_task_acquire_not_zero - Acquire a reference to a rcu task object. A task
1849 * acquired by this kfunc which is not stored in a map as a kptr, must be
1850 * released by calling bpf_task_release().
1851 * @p: The task on which a reference is being acquired.
1852 */
1853struct task_struct *bpf_task_acquire_not_zero(struct task_struct *p)
1854{
1855 /* For the time being this function returns NULL, as it's not currently
1856 * possible to safely acquire a reference to a task with RCU protection
1857 * using get_task_struct() and put_task_struct(). This is due to the
1858 * slightly odd mechanics of p->rcu_users, and how task RCU protection
1859 * works.
1860 *
1861 * A struct task_struct is refcounted by two different refcount_t
1862 * fields:
1863 *
1864 * 1. p->usage: The "true" refcount field which tracks a task's
1865 * lifetime. The task is freed as soon as this
1866 * refcount drops to 0.
1867 *
1868 * 2. p->rcu_users: An "RCU users" refcount field which is statically
1869 * initialized to 2, and is co-located in a union with
1870 * a struct rcu_head field (p->rcu). p->rcu_users
1871 * essentially encapsulates a single p->usage
1872 * refcount, and when p->rcu_users goes to 0, an RCU
1873 * callback is scheduled on the struct rcu_head which
1874 * decrements the p->usage refcount.
1875 *
1876 * There are two important implications to this task refcounting logic
1877 * described above. The first is that
1878 * refcount_inc_not_zero(&p->rcu_users) cannot be used anywhere, as
1879 * after the refcount goes to 0, the RCU callback being scheduled will
1880 * cause the memory backing the refcount to again be nonzero due to the
1881 * fields sharing a union. The other is that we can't rely on RCU to
1882 * guarantee that a task is valid in a BPF program. This is because a
1883 * task could have already transitioned to being in the TASK_DEAD
1884 * state, had its rcu_users refcount go to 0, and its rcu callback
1885 * invoked in which it drops its single p->usage reference. At this
1886 * point the task will be freed as soon as the last p->usage reference
1887 * goes to 0, without waiting for another RCU gp to elapse. The only
1888 * way that a BPF program can guarantee that a task is valid is in this
1889 * scenario is to hold a p->usage refcount itself.
1890 *
1891 * Until we're able to resolve this issue, either by pulling
1892 * p->rcu_users and p->rcu out of the union, or by getting rid of
1893 * p->usage and just using p->rcu_users for refcounting, we'll just
1894 * return NULL here.
1895 */
1896 return NULL;
1897}
1898
1899/**
1900 * bpf_task_kptr_get - Acquire a reference on a struct task_struct kptr. A task
1901 * kptr acquired by this kfunc which is not subsequently stored in a map, must
1902 * be released by calling bpf_task_release().
1903 * @pp: A pointer to a task kptr on which a reference is being acquired.
1904 */
1905struct task_struct *bpf_task_kptr_get(struct task_struct **pp)
1906{
1907 /* We must return NULL here until we have clarity on how to properly
1908 * leverage RCU for ensuring a task's lifetime. See the comment above
1909 * in bpf_task_acquire_not_zero() for more details.
1910 */
1911 return NULL;
1912}
1913
1914/**
1915 * bpf_task_release - Release the reference acquired on a task.
1916 * @p: The task on which a reference is being released.
1917 */
1918void bpf_task_release(struct task_struct *p)
1919{
1920 if (!p)
1921 return;
1922
1923 put_task_struct(p);
1924}
1925
1926#ifdef CONFIG_CGROUPS
1927/**
1928 * bpf_cgroup_acquire - Acquire a reference to a cgroup. A cgroup acquired by
1929 * this kfunc which is not stored in a map as a kptr, must be released by
1930 * calling bpf_cgroup_release().
1931 * @cgrp: The cgroup on which a reference is being acquired.
1932 */
1933struct cgroup *bpf_cgroup_acquire(struct cgroup *cgrp)
1934{
1935 cgroup_get(cgrp);
1936 return cgrp;
1937}
1938
1939/**
1940 * bpf_cgroup_kptr_get - Acquire a reference on a struct cgroup kptr. A cgroup
1941 * kptr acquired by this kfunc which is not subsequently stored in a map, must
1942 * be released by calling bpf_cgroup_release().
1943 * @cgrpp: A pointer to a cgroup kptr on which a reference is being acquired.
1944 */
1945struct cgroup *bpf_cgroup_kptr_get(struct cgroup **cgrpp)
1946{
1947 struct cgroup *cgrp;
1948
1949 rcu_read_lock();
1950 /* Another context could remove the cgroup from the map and release it
1951 * at any time, including after we've done the lookup above. This is
1952 * safe because we're in an RCU read region, so the cgroup is
1953 * guaranteed to remain valid until at least the rcu_read_unlock()
1954 * below.
1955 */
1956 cgrp = READ_ONCE(*cgrpp);
1957
1958 if (cgrp && !cgroup_tryget(cgrp))
1959 /* If the cgroup had been removed from the map and freed as
1960 * described above, cgroup_tryget() will return false. The
1961 * cgroup will be freed at some point after the current RCU gp
1962 * has ended, so just return NULL to the user.
1963 */
1964 cgrp = NULL;
1965 rcu_read_unlock();
1966
1967 return cgrp;
1968}
1969
1970/**
1971 * bpf_cgroup_release - Release the reference acquired on a cgroup.
1972 * If this kfunc is invoked in an RCU read region, the cgroup is guaranteed to
1973 * not be freed until the current grace period has ended, even if its refcount
1974 * drops to 0.
1975 * @cgrp: The cgroup on which a reference is being released.
1976 */
1977void bpf_cgroup_release(struct cgroup *cgrp)
1978{
1979 if (!cgrp)
1980 return;
1981
1982 cgroup_put(cgrp);
1983}
1984
1985/**
1986 * bpf_cgroup_ancestor - Perform a lookup on an entry in a cgroup's ancestor
1987 * array. A cgroup returned by this kfunc which is not subsequently stored in a
1988 * map, must be released by calling bpf_cgroup_release().
1989 * @cgrp: The cgroup for which we're performing a lookup.
1990 * @level: The level of ancestor to look up.
1991 */
1992struct cgroup *bpf_cgroup_ancestor(struct cgroup *cgrp, int level)
1993{
1994 struct cgroup *ancestor;
1995
1996 if (level > cgrp->level || level < 0)
1997 return NULL;
1998
1999 ancestor = cgrp->ancestors[level];
2000 cgroup_get(ancestor);
2001 return ancestor;
2002}
2003#endif /* CONFIG_CGROUPS */
2004
2005/**
2006 * bpf_task_from_pid - Find a struct task_struct from its pid by looking it up
2007 * in the root pid namespace idr. If a task is returned, it must either be
2008 * stored in a map, or released with bpf_task_release().
2009 * @pid: The pid of the task being looked up.
2010 */
2011struct task_struct *bpf_task_from_pid(s32 pid)
2012{
2013 struct task_struct *p;
2014
2015 rcu_read_lock();
2016 p = find_task_by_pid_ns(pid, &init_pid_ns);
2017 if (p)
2018 bpf_task_acquire(p);
2019 rcu_read_unlock();
2020
2021 return p;
2022}
2023
2024void *bpf_cast_to_kern_ctx(void *obj)
2025{
2026 return obj;
2027}
2028
2029void *bpf_rdonly_cast(void *obj__ign, u32 btf_id__k)
2030{
2031 return obj__ign;
2032}
2033
2034void bpf_rcu_read_lock(void)
2035{
2036 rcu_read_lock();
2037}
2038
2039void bpf_rcu_read_unlock(void)
2040{
2041 rcu_read_unlock();
2042}
2043
2044__diag_pop();
2045
2046BTF_SET8_START(generic_btf_ids)
2047#ifdef CONFIG_KEXEC_CORE
2048BTF_ID_FLAGS(func, crash_kexec, KF_DESTRUCTIVE)
2049#endif
2050BTF_ID_FLAGS(func, bpf_obj_new_impl, KF_ACQUIRE | KF_RET_NULL)
2051BTF_ID_FLAGS(func, bpf_obj_drop_impl, KF_RELEASE)
2052BTF_ID_FLAGS(func, bpf_list_push_front)
2053BTF_ID_FLAGS(func, bpf_list_push_back)
2054BTF_ID_FLAGS(func, bpf_list_pop_front, KF_ACQUIRE | KF_RET_NULL)
2055BTF_ID_FLAGS(func, bpf_list_pop_back, KF_ACQUIRE | KF_RET_NULL)
2056BTF_ID_FLAGS(func, bpf_task_acquire, KF_ACQUIRE | KF_TRUSTED_ARGS)
2057BTF_ID_FLAGS(func, bpf_task_acquire_not_zero, KF_ACQUIRE | KF_RCU | KF_RET_NULL)
2058BTF_ID_FLAGS(func, bpf_task_kptr_get, KF_ACQUIRE | KF_KPTR_GET | KF_RET_NULL)
2059BTF_ID_FLAGS(func, bpf_task_release, KF_RELEASE)
2060#ifdef CONFIG_CGROUPS
2061BTF_ID_FLAGS(func, bpf_cgroup_acquire, KF_ACQUIRE | KF_TRUSTED_ARGS)
2062BTF_ID_FLAGS(func, bpf_cgroup_kptr_get, KF_ACQUIRE | KF_KPTR_GET | KF_RET_NULL)
2063BTF_ID_FLAGS(func, bpf_cgroup_release, KF_RELEASE)
2064BTF_ID_FLAGS(func, bpf_cgroup_ancestor, KF_ACQUIRE | KF_TRUSTED_ARGS | KF_RET_NULL)
2065#endif
2066BTF_ID_FLAGS(func, bpf_task_from_pid, KF_ACQUIRE | KF_RET_NULL)
2067BTF_SET8_END(generic_btf_ids)
2068
2069static const struct btf_kfunc_id_set generic_kfunc_set = {
2070 .owner = THIS_MODULE,
2071 .set = &generic_btf_ids,
2072};
2073
2074
2075BTF_ID_LIST(generic_dtor_ids)
2076BTF_ID(struct, task_struct)
2077BTF_ID(func, bpf_task_release)
2078#ifdef CONFIG_CGROUPS
2079BTF_ID(struct, cgroup)
2080BTF_ID(func, bpf_cgroup_release)
2081#endif
2082
2083BTF_SET8_START(common_btf_ids)
2084BTF_ID_FLAGS(func, bpf_cast_to_kern_ctx)
2085BTF_ID_FLAGS(func, bpf_rdonly_cast)
2086BTF_ID_FLAGS(func, bpf_rcu_read_lock)
2087BTF_ID_FLAGS(func, bpf_rcu_read_unlock)
2088BTF_SET8_END(common_btf_ids)
2089
2090static const struct btf_kfunc_id_set common_kfunc_set = {
2091 .owner = THIS_MODULE,
2092 .set = &common_btf_ids,
2093};
2094
2095static int __init kfunc_init(void)
2096{
2097 int ret;
2098 const struct btf_id_dtor_kfunc generic_dtors[] = {
2099 {
2100 .btf_id = generic_dtor_ids[0],
2101 .kfunc_btf_id = generic_dtor_ids[1]
2102 },
2103#ifdef CONFIG_CGROUPS
2104 {
2105 .btf_id = generic_dtor_ids[2],
2106 .kfunc_btf_id = generic_dtor_ids[3]
2107 },
2108#endif
2109 };
2110
2111 ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, &generic_kfunc_set);
2112 ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS, &generic_kfunc_set);
2113 ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_STRUCT_OPS, &generic_kfunc_set);
2114 ret = ret ?: register_btf_id_dtor_kfuncs(generic_dtors,
2115 ARRAY_SIZE(generic_dtors),
2116 THIS_MODULE);
2117 return ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_UNSPEC, &common_kfunc_set);
2118}
2119
2120late_initcall(kfunc_init);