xref: /linux/kernel/bpf/helpers.c (revision 42422993cf28d456778ee9168d73758ec037cd51)
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/sched/task.h>
22 #include <linux/security.h>
23 #include <linux/btf_ids.h>
24 #include <linux/bpf_mem_alloc.h>
25 #include <linux/kasan.h>
26 
27 #include "../../lib/kstrtox.h"
28 
29 /* If kernel subsystem is allowing eBPF programs to call this function,
30  * inside its own verifier_ops->get_func_proto() callback it should return
31  * bpf_map_lookup_elem_proto, so that verifier can properly check the arguments
32  *
33  * Different map implementations will rely on rcu in map methods
34  * lookup/update/delete, therefore eBPF programs must run under rcu lock
35  * if program is allowed to access maps, so check rcu_read_lock_held in
36  * all three functions.
37  */
38 BPF_CALL_2(bpf_map_lookup_elem, struct bpf_map *, map, void *, key)
39 {
40 	WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
41 	return (unsigned long) map->ops->map_lookup_elem(map, key);
42 }
43 
44 const struct bpf_func_proto bpf_map_lookup_elem_proto = {
45 	.func		= bpf_map_lookup_elem,
46 	.gpl_only	= false,
47 	.pkt_access	= true,
48 	.ret_type	= RET_PTR_TO_MAP_VALUE_OR_NULL,
49 	.arg1_type	= ARG_CONST_MAP_PTR,
50 	.arg2_type	= ARG_PTR_TO_MAP_KEY,
51 };
52 
53 BPF_CALL_4(bpf_map_update_elem, struct bpf_map *, map, void *, key,
54 	   void *, value, u64, flags)
55 {
56 	WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
57 	return map->ops->map_update_elem(map, key, value, flags);
58 }
59 
60 const struct bpf_func_proto bpf_map_update_elem_proto = {
61 	.func		= bpf_map_update_elem,
62 	.gpl_only	= false,
63 	.pkt_access	= true,
64 	.ret_type	= RET_INTEGER,
65 	.arg1_type	= ARG_CONST_MAP_PTR,
66 	.arg2_type	= ARG_PTR_TO_MAP_KEY,
67 	.arg3_type	= ARG_PTR_TO_MAP_VALUE,
68 	.arg4_type	= ARG_ANYTHING,
69 };
70 
71 BPF_CALL_2(bpf_map_delete_elem, struct bpf_map *, map, void *, key)
72 {
73 	WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
74 	return map->ops->map_delete_elem(map, key);
75 }
76 
77 const struct bpf_func_proto bpf_map_delete_elem_proto = {
78 	.func		= bpf_map_delete_elem,
79 	.gpl_only	= false,
80 	.pkt_access	= true,
81 	.ret_type	= RET_INTEGER,
82 	.arg1_type	= ARG_CONST_MAP_PTR,
83 	.arg2_type	= ARG_PTR_TO_MAP_KEY,
84 };
85 
86 BPF_CALL_3(bpf_map_push_elem, struct bpf_map *, map, void *, value, u64, flags)
87 {
88 	return map->ops->map_push_elem(map, value, flags);
89 }
90 
91 const struct bpf_func_proto bpf_map_push_elem_proto = {
92 	.func		= bpf_map_push_elem,
93 	.gpl_only	= false,
94 	.pkt_access	= true,
95 	.ret_type	= RET_INTEGER,
96 	.arg1_type	= ARG_CONST_MAP_PTR,
97 	.arg2_type	= ARG_PTR_TO_MAP_VALUE,
98 	.arg3_type	= ARG_ANYTHING,
99 };
100 
101 BPF_CALL_2(bpf_map_pop_elem, struct bpf_map *, map, void *, value)
102 {
103 	return map->ops->map_pop_elem(map, value);
104 }
105 
106 const struct bpf_func_proto bpf_map_pop_elem_proto = {
107 	.func		= bpf_map_pop_elem,
108 	.gpl_only	= false,
109 	.ret_type	= RET_INTEGER,
110 	.arg1_type	= ARG_CONST_MAP_PTR,
111 	.arg2_type	= ARG_PTR_TO_MAP_VALUE | MEM_UNINIT,
112 };
113 
114 BPF_CALL_2(bpf_map_peek_elem, struct bpf_map *, map, void *, value)
115 {
116 	return map->ops->map_peek_elem(map, value);
117 }
118 
119 const struct bpf_func_proto bpf_map_peek_elem_proto = {
120 	.func		= bpf_map_peek_elem,
121 	.gpl_only	= false,
122 	.ret_type	= RET_INTEGER,
123 	.arg1_type	= ARG_CONST_MAP_PTR,
124 	.arg2_type	= ARG_PTR_TO_MAP_VALUE | MEM_UNINIT,
125 };
126 
127 BPF_CALL_3(bpf_map_lookup_percpu_elem, struct bpf_map *, map, void *, key, u32, cpu)
128 {
129 	WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
130 	return (unsigned long) map->ops->map_lookup_percpu_elem(map, key, cpu);
131 }
132 
133 const struct bpf_func_proto bpf_map_lookup_percpu_elem_proto = {
134 	.func		= bpf_map_lookup_percpu_elem,
135 	.gpl_only	= false,
136 	.pkt_access	= true,
137 	.ret_type	= RET_PTR_TO_MAP_VALUE_OR_NULL,
138 	.arg1_type	= ARG_CONST_MAP_PTR,
139 	.arg2_type	= ARG_PTR_TO_MAP_KEY,
140 	.arg3_type	= ARG_ANYTHING,
141 };
142 
143 const struct bpf_func_proto bpf_get_prandom_u32_proto = {
144 	.func		= bpf_user_rnd_u32,
145 	.gpl_only	= false,
146 	.ret_type	= RET_INTEGER,
147 };
148 
149 BPF_CALL_0(bpf_get_smp_processor_id)
150 {
151 	return smp_processor_id();
152 }
153 
154 const struct bpf_func_proto bpf_get_smp_processor_id_proto = {
155 	.func		= bpf_get_smp_processor_id,
156 	.gpl_only	= false,
157 	.ret_type	= RET_INTEGER,
158 };
159 
160 BPF_CALL_0(bpf_get_numa_node_id)
161 {
162 	return numa_node_id();
163 }
164 
165 const struct bpf_func_proto bpf_get_numa_node_id_proto = {
166 	.func		= bpf_get_numa_node_id,
167 	.gpl_only	= false,
168 	.ret_type	= RET_INTEGER,
169 };
170 
171 BPF_CALL_0(bpf_ktime_get_ns)
172 {
173 	/* NMI safe access to clock monotonic */
174 	return ktime_get_mono_fast_ns();
175 }
176 
177 const struct bpf_func_proto bpf_ktime_get_ns_proto = {
178 	.func		= bpf_ktime_get_ns,
179 	.gpl_only	= false,
180 	.ret_type	= RET_INTEGER,
181 };
182 
183 BPF_CALL_0(bpf_ktime_get_boot_ns)
184 {
185 	/* NMI safe access to clock boottime */
186 	return ktime_get_boot_fast_ns();
187 }
188 
189 const struct bpf_func_proto bpf_ktime_get_boot_ns_proto = {
190 	.func		= bpf_ktime_get_boot_ns,
191 	.gpl_only	= false,
192 	.ret_type	= RET_INTEGER,
193 };
194 
195 BPF_CALL_0(bpf_ktime_get_coarse_ns)
196 {
197 	return ktime_get_coarse_ns();
198 }
199 
200 const struct bpf_func_proto bpf_ktime_get_coarse_ns_proto = {
201 	.func		= bpf_ktime_get_coarse_ns,
202 	.gpl_only	= false,
203 	.ret_type	= RET_INTEGER,
204 };
205 
206 BPF_CALL_0(bpf_ktime_get_tai_ns)
207 {
208 	/* NMI safe access to clock tai */
209 	return ktime_get_tai_fast_ns();
210 }
211 
212 const struct bpf_func_proto bpf_ktime_get_tai_ns_proto = {
213 	.func		= bpf_ktime_get_tai_ns,
214 	.gpl_only	= false,
215 	.ret_type	= RET_INTEGER,
216 };
217 
218 BPF_CALL_0(bpf_get_current_pid_tgid)
219 {
220 	struct task_struct *task = current;
221 
222 	if (unlikely(!task))
223 		return -EINVAL;
224 
225 	return (u64) task->tgid << 32 | task->pid;
226 }
227 
228 const struct bpf_func_proto bpf_get_current_pid_tgid_proto = {
229 	.func		= bpf_get_current_pid_tgid,
230 	.gpl_only	= false,
231 	.ret_type	= RET_INTEGER,
232 };
233 
234 BPF_CALL_0(bpf_get_current_uid_gid)
235 {
236 	struct task_struct *task = current;
237 	kuid_t uid;
238 	kgid_t gid;
239 
240 	if (unlikely(!task))
241 		return -EINVAL;
242 
243 	current_uid_gid(&uid, &gid);
244 	return (u64) from_kgid(&init_user_ns, gid) << 32 |
245 		     from_kuid(&init_user_ns, uid);
246 }
247 
248 const struct bpf_func_proto bpf_get_current_uid_gid_proto = {
249 	.func		= bpf_get_current_uid_gid,
250 	.gpl_only	= false,
251 	.ret_type	= RET_INTEGER,
252 };
253 
254 BPF_CALL_2(bpf_get_current_comm, char *, buf, u32, size)
255 {
256 	struct task_struct *task = current;
257 
258 	if (unlikely(!task))
259 		goto err_clear;
260 
261 	/* Verifier guarantees that size > 0 */
262 	strscpy_pad(buf, task->comm, size);
263 	return 0;
264 err_clear:
265 	memset(buf, 0, size);
266 	return -EINVAL;
267 }
268 
269 const struct bpf_func_proto bpf_get_current_comm_proto = {
270 	.func		= bpf_get_current_comm,
271 	.gpl_only	= false,
272 	.ret_type	= RET_INTEGER,
273 	.arg1_type	= ARG_PTR_TO_UNINIT_MEM,
274 	.arg2_type	= ARG_CONST_SIZE,
275 };
276 
277 #if defined(CONFIG_QUEUED_SPINLOCKS) || defined(CONFIG_BPF_ARCH_SPINLOCK)
278 
279 static inline void __bpf_spin_lock(struct bpf_spin_lock *lock)
280 {
281 	arch_spinlock_t *l = (void *)lock;
282 	union {
283 		__u32 val;
284 		arch_spinlock_t lock;
285 	} u = { .lock = __ARCH_SPIN_LOCK_UNLOCKED };
286 
287 	compiletime_assert(u.val == 0, "__ARCH_SPIN_LOCK_UNLOCKED not 0");
288 	BUILD_BUG_ON(sizeof(*l) != sizeof(__u32));
289 	BUILD_BUG_ON(sizeof(*lock) != sizeof(__u32));
290 	preempt_disable();
291 	arch_spin_lock(l);
292 }
293 
294 static inline void __bpf_spin_unlock(struct bpf_spin_lock *lock)
295 {
296 	arch_spinlock_t *l = (void *)lock;
297 
298 	arch_spin_unlock(l);
299 	preempt_enable();
300 }
301 
302 #else
303 
304 static inline void __bpf_spin_lock(struct bpf_spin_lock *lock)
305 {
306 	atomic_t *l = (void *)lock;
307 
308 	BUILD_BUG_ON(sizeof(*l) != sizeof(*lock));
309 	do {
310 		atomic_cond_read_relaxed(l, !VAL);
311 	} while (atomic_xchg(l, 1));
312 }
313 
314 static inline void __bpf_spin_unlock(struct bpf_spin_lock *lock)
315 {
316 	atomic_t *l = (void *)lock;
317 
318 	atomic_set_release(l, 0);
319 }
320 
321 #endif
322 
323 static DEFINE_PER_CPU(unsigned long, irqsave_flags);
324 
325 static inline void __bpf_spin_lock_irqsave(struct bpf_spin_lock *lock)
326 {
327 	unsigned long flags;
328 
329 	local_irq_save(flags);
330 	__bpf_spin_lock(lock);
331 	__this_cpu_write(irqsave_flags, flags);
332 }
333 
334 notrace BPF_CALL_1(bpf_spin_lock, struct bpf_spin_lock *, lock)
335 {
336 	__bpf_spin_lock_irqsave(lock);
337 	return 0;
338 }
339 
340 const struct bpf_func_proto bpf_spin_lock_proto = {
341 	.func		= bpf_spin_lock,
342 	.gpl_only	= false,
343 	.ret_type	= RET_VOID,
344 	.arg1_type	= ARG_PTR_TO_SPIN_LOCK,
345 	.arg1_btf_id    = BPF_PTR_POISON,
346 };
347 
348 static inline void __bpf_spin_unlock_irqrestore(struct bpf_spin_lock *lock)
349 {
350 	unsigned long flags;
351 
352 	flags = __this_cpu_read(irqsave_flags);
353 	__bpf_spin_unlock(lock);
354 	local_irq_restore(flags);
355 }
356 
357 notrace BPF_CALL_1(bpf_spin_unlock, struct bpf_spin_lock *, lock)
358 {
359 	__bpf_spin_unlock_irqrestore(lock);
360 	return 0;
361 }
362 
363 const struct bpf_func_proto bpf_spin_unlock_proto = {
364 	.func		= bpf_spin_unlock,
365 	.gpl_only	= false,
366 	.ret_type	= RET_VOID,
367 	.arg1_type	= ARG_PTR_TO_SPIN_LOCK,
368 	.arg1_btf_id    = BPF_PTR_POISON,
369 };
370 
371 void copy_map_value_locked(struct bpf_map *map, void *dst, void *src,
372 			   bool lock_src)
373 {
374 	struct bpf_spin_lock *lock;
375 
376 	if (lock_src)
377 		lock = src + map->record->spin_lock_off;
378 	else
379 		lock = dst + map->record->spin_lock_off;
380 	preempt_disable();
381 	__bpf_spin_lock_irqsave(lock);
382 	copy_map_value(map, dst, src);
383 	__bpf_spin_unlock_irqrestore(lock);
384 	preempt_enable();
385 }
386 
387 BPF_CALL_0(bpf_jiffies64)
388 {
389 	return get_jiffies_64();
390 }
391 
392 const struct bpf_func_proto bpf_jiffies64_proto = {
393 	.func		= bpf_jiffies64,
394 	.gpl_only	= false,
395 	.ret_type	= RET_INTEGER,
396 };
397 
398 #ifdef CONFIG_CGROUPS
399 BPF_CALL_0(bpf_get_current_cgroup_id)
400 {
401 	struct cgroup *cgrp;
402 	u64 cgrp_id;
403 
404 	rcu_read_lock();
405 	cgrp = task_dfl_cgroup(current);
406 	cgrp_id = cgroup_id(cgrp);
407 	rcu_read_unlock();
408 
409 	return cgrp_id;
410 }
411 
412 const struct bpf_func_proto bpf_get_current_cgroup_id_proto = {
413 	.func		= bpf_get_current_cgroup_id,
414 	.gpl_only	= false,
415 	.ret_type	= RET_INTEGER,
416 };
417 
418 BPF_CALL_1(bpf_get_current_ancestor_cgroup_id, int, ancestor_level)
419 {
420 	struct cgroup *cgrp;
421 	struct cgroup *ancestor;
422 	u64 cgrp_id;
423 
424 	rcu_read_lock();
425 	cgrp = task_dfl_cgroup(current);
426 	ancestor = cgroup_ancestor(cgrp, ancestor_level);
427 	cgrp_id = ancestor ? cgroup_id(ancestor) : 0;
428 	rcu_read_unlock();
429 
430 	return cgrp_id;
431 }
432 
433 const struct bpf_func_proto bpf_get_current_ancestor_cgroup_id_proto = {
434 	.func		= bpf_get_current_ancestor_cgroup_id,
435 	.gpl_only	= false,
436 	.ret_type	= RET_INTEGER,
437 	.arg1_type	= ARG_ANYTHING,
438 };
439 #endif /* CONFIG_CGROUPS */
440 
441 #define BPF_STRTOX_BASE_MASK 0x1F
442 
443 static int __bpf_strtoull(const char *buf, size_t buf_len, u64 flags,
444 			  unsigned long long *res, bool *is_negative)
445 {
446 	unsigned int base = flags & BPF_STRTOX_BASE_MASK;
447 	const char *cur_buf = buf;
448 	size_t cur_len = buf_len;
449 	unsigned int consumed;
450 	size_t val_len;
451 	char str[64];
452 
453 	if (!buf || !buf_len || !res || !is_negative)
454 		return -EINVAL;
455 
456 	if (base != 0 && base != 8 && base != 10 && base != 16)
457 		return -EINVAL;
458 
459 	if (flags & ~BPF_STRTOX_BASE_MASK)
460 		return -EINVAL;
461 
462 	while (cur_buf < buf + buf_len && isspace(*cur_buf))
463 		++cur_buf;
464 
465 	*is_negative = (cur_buf < buf + buf_len && *cur_buf == '-');
466 	if (*is_negative)
467 		++cur_buf;
468 
469 	consumed = cur_buf - buf;
470 	cur_len -= consumed;
471 	if (!cur_len)
472 		return -EINVAL;
473 
474 	cur_len = min(cur_len, sizeof(str) - 1);
475 	memcpy(str, cur_buf, cur_len);
476 	str[cur_len] = '\0';
477 	cur_buf = str;
478 
479 	cur_buf = _parse_integer_fixup_radix(cur_buf, &base);
480 	val_len = _parse_integer(cur_buf, base, res);
481 
482 	if (val_len & KSTRTOX_OVERFLOW)
483 		return -ERANGE;
484 
485 	if (val_len == 0)
486 		return -EINVAL;
487 
488 	cur_buf += val_len;
489 	consumed += cur_buf - str;
490 
491 	return consumed;
492 }
493 
494 static int __bpf_strtoll(const char *buf, size_t buf_len, u64 flags,
495 			 long long *res)
496 {
497 	unsigned long long _res;
498 	bool is_negative;
499 	int err;
500 
501 	err = __bpf_strtoull(buf, buf_len, flags, &_res, &is_negative);
502 	if (err < 0)
503 		return err;
504 	if (is_negative) {
505 		if ((long long)-_res > 0)
506 			return -ERANGE;
507 		*res = -_res;
508 	} else {
509 		if ((long long)_res < 0)
510 			return -ERANGE;
511 		*res = _res;
512 	}
513 	return err;
514 }
515 
516 BPF_CALL_4(bpf_strtol, const char *, buf, size_t, buf_len, u64, flags,
517 	   long *, res)
518 {
519 	long long _res;
520 	int err;
521 
522 	err = __bpf_strtoll(buf, buf_len, flags, &_res);
523 	if (err < 0)
524 		return err;
525 	if (_res != (long)_res)
526 		return -ERANGE;
527 	*res = _res;
528 	return err;
529 }
530 
531 const struct bpf_func_proto bpf_strtol_proto = {
532 	.func		= bpf_strtol,
533 	.gpl_only	= false,
534 	.ret_type	= RET_INTEGER,
535 	.arg1_type	= ARG_PTR_TO_MEM | MEM_RDONLY,
536 	.arg2_type	= ARG_CONST_SIZE,
537 	.arg3_type	= ARG_ANYTHING,
538 	.arg4_type	= ARG_PTR_TO_LONG,
539 };
540 
541 BPF_CALL_4(bpf_strtoul, const char *, buf, size_t, buf_len, u64, flags,
542 	   unsigned long *, res)
543 {
544 	unsigned long long _res;
545 	bool is_negative;
546 	int err;
547 
548 	err = __bpf_strtoull(buf, buf_len, flags, &_res, &is_negative);
549 	if (err < 0)
550 		return err;
551 	if (is_negative)
552 		return -EINVAL;
553 	if (_res != (unsigned long)_res)
554 		return -ERANGE;
555 	*res = _res;
556 	return err;
557 }
558 
559 const struct bpf_func_proto bpf_strtoul_proto = {
560 	.func		= bpf_strtoul,
561 	.gpl_only	= false,
562 	.ret_type	= RET_INTEGER,
563 	.arg1_type	= ARG_PTR_TO_MEM | MEM_RDONLY,
564 	.arg2_type	= ARG_CONST_SIZE,
565 	.arg3_type	= ARG_ANYTHING,
566 	.arg4_type	= ARG_PTR_TO_LONG,
567 };
568 
569 BPF_CALL_3(bpf_strncmp, const char *, s1, u32, s1_sz, const char *, s2)
570 {
571 	return strncmp(s1, s2, s1_sz);
572 }
573 
574 static const struct bpf_func_proto bpf_strncmp_proto = {
575 	.func		= bpf_strncmp,
576 	.gpl_only	= false,
577 	.ret_type	= RET_INTEGER,
578 	.arg1_type	= ARG_PTR_TO_MEM | MEM_RDONLY,
579 	.arg2_type	= ARG_CONST_SIZE,
580 	.arg3_type	= ARG_PTR_TO_CONST_STR,
581 };
582 
583 BPF_CALL_4(bpf_get_ns_current_pid_tgid, u64, dev, u64, ino,
584 	   struct bpf_pidns_info *, nsdata, u32, size)
585 {
586 	struct task_struct *task = current;
587 	struct pid_namespace *pidns;
588 	int err = -EINVAL;
589 
590 	if (unlikely(size != sizeof(struct bpf_pidns_info)))
591 		goto clear;
592 
593 	if (unlikely((u64)(dev_t)dev != dev))
594 		goto clear;
595 
596 	if (unlikely(!task))
597 		goto clear;
598 
599 	pidns = task_active_pid_ns(task);
600 	if (unlikely(!pidns)) {
601 		err = -ENOENT;
602 		goto clear;
603 	}
604 
605 	if (!ns_match(&pidns->ns, (dev_t)dev, ino))
606 		goto clear;
607 
608 	nsdata->pid = task_pid_nr_ns(task, pidns);
609 	nsdata->tgid = task_tgid_nr_ns(task, pidns);
610 	return 0;
611 clear:
612 	memset((void *)nsdata, 0, (size_t) size);
613 	return err;
614 }
615 
616 const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto = {
617 	.func		= bpf_get_ns_current_pid_tgid,
618 	.gpl_only	= false,
619 	.ret_type	= RET_INTEGER,
620 	.arg1_type	= ARG_ANYTHING,
621 	.arg2_type	= ARG_ANYTHING,
622 	.arg3_type      = ARG_PTR_TO_UNINIT_MEM,
623 	.arg4_type      = ARG_CONST_SIZE,
624 };
625 
626 static const struct bpf_func_proto bpf_get_raw_smp_processor_id_proto = {
627 	.func		= bpf_get_raw_cpu_id,
628 	.gpl_only	= false,
629 	.ret_type	= RET_INTEGER,
630 };
631 
632 BPF_CALL_5(bpf_event_output_data, void *, ctx, struct bpf_map *, map,
633 	   u64, flags, void *, data, u64, size)
634 {
635 	if (unlikely(flags & ~(BPF_F_INDEX_MASK)))
636 		return -EINVAL;
637 
638 	return bpf_event_output(map, flags, data, size, NULL, 0, NULL);
639 }
640 
641 const struct bpf_func_proto bpf_event_output_data_proto =  {
642 	.func		= bpf_event_output_data,
643 	.gpl_only       = true,
644 	.ret_type       = RET_INTEGER,
645 	.arg1_type      = ARG_PTR_TO_CTX,
646 	.arg2_type      = ARG_CONST_MAP_PTR,
647 	.arg3_type      = ARG_ANYTHING,
648 	.arg4_type      = ARG_PTR_TO_MEM | MEM_RDONLY,
649 	.arg5_type      = ARG_CONST_SIZE_OR_ZERO,
650 };
651 
652 BPF_CALL_3(bpf_copy_from_user, void *, dst, u32, size,
653 	   const void __user *, user_ptr)
654 {
655 	int ret = copy_from_user(dst, user_ptr, size);
656 
657 	if (unlikely(ret)) {
658 		memset(dst, 0, size);
659 		ret = -EFAULT;
660 	}
661 
662 	return ret;
663 }
664 
665 const struct bpf_func_proto bpf_copy_from_user_proto = {
666 	.func		= bpf_copy_from_user,
667 	.gpl_only	= false,
668 	.might_sleep	= true,
669 	.ret_type	= RET_INTEGER,
670 	.arg1_type	= ARG_PTR_TO_UNINIT_MEM,
671 	.arg2_type	= ARG_CONST_SIZE_OR_ZERO,
672 	.arg3_type	= ARG_ANYTHING,
673 };
674 
675 BPF_CALL_5(bpf_copy_from_user_task, void *, dst, u32, size,
676 	   const void __user *, user_ptr, struct task_struct *, tsk, u64, flags)
677 {
678 	int ret;
679 
680 	/* flags is not used yet */
681 	if (unlikely(flags))
682 		return -EINVAL;
683 
684 	if (unlikely(!size))
685 		return 0;
686 
687 	ret = access_process_vm(tsk, (unsigned long)user_ptr, dst, size, 0);
688 	if (ret == size)
689 		return 0;
690 
691 	memset(dst, 0, size);
692 	/* Return -EFAULT for partial read */
693 	return ret < 0 ? ret : -EFAULT;
694 }
695 
696 const struct bpf_func_proto bpf_copy_from_user_task_proto = {
697 	.func		= bpf_copy_from_user_task,
698 	.gpl_only	= true,
699 	.might_sleep	= true,
700 	.ret_type	= RET_INTEGER,
701 	.arg1_type	= ARG_PTR_TO_UNINIT_MEM,
702 	.arg2_type	= ARG_CONST_SIZE_OR_ZERO,
703 	.arg3_type	= ARG_ANYTHING,
704 	.arg4_type	= ARG_PTR_TO_BTF_ID,
705 	.arg4_btf_id	= &btf_tracing_ids[BTF_TRACING_TYPE_TASK],
706 	.arg5_type	= ARG_ANYTHING
707 };
708 
709 BPF_CALL_2(bpf_per_cpu_ptr, const void *, ptr, u32, cpu)
710 {
711 	if (cpu >= nr_cpu_ids)
712 		return (unsigned long)NULL;
713 
714 	return (unsigned long)per_cpu_ptr((const void __percpu *)ptr, cpu);
715 }
716 
717 const struct bpf_func_proto bpf_per_cpu_ptr_proto = {
718 	.func		= bpf_per_cpu_ptr,
719 	.gpl_only	= false,
720 	.ret_type	= RET_PTR_TO_MEM_OR_BTF_ID | PTR_MAYBE_NULL | MEM_RDONLY,
721 	.arg1_type	= ARG_PTR_TO_PERCPU_BTF_ID,
722 	.arg2_type	= ARG_ANYTHING,
723 };
724 
725 BPF_CALL_1(bpf_this_cpu_ptr, const void *, percpu_ptr)
726 {
727 	return (unsigned long)this_cpu_ptr((const void __percpu *)percpu_ptr);
728 }
729 
730 const struct bpf_func_proto bpf_this_cpu_ptr_proto = {
731 	.func		= bpf_this_cpu_ptr,
732 	.gpl_only	= false,
733 	.ret_type	= RET_PTR_TO_MEM_OR_BTF_ID | MEM_RDONLY,
734 	.arg1_type	= ARG_PTR_TO_PERCPU_BTF_ID,
735 };
736 
737 static int bpf_trace_copy_string(char *buf, void *unsafe_ptr, char fmt_ptype,
738 		size_t bufsz)
739 {
740 	void __user *user_ptr = (__force void __user *)unsafe_ptr;
741 
742 	buf[0] = 0;
743 
744 	switch (fmt_ptype) {
745 	case 's':
746 #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
747 		if ((unsigned long)unsafe_ptr < TASK_SIZE)
748 			return strncpy_from_user_nofault(buf, user_ptr, bufsz);
749 		fallthrough;
750 #endif
751 	case 'k':
752 		return strncpy_from_kernel_nofault(buf, unsafe_ptr, bufsz);
753 	case 'u':
754 		return strncpy_from_user_nofault(buf, user_ptr, bufsz);
755 	}
756 
757 	return -EINVAL;
758 }
759 
760 /* Per-cpu temp buffers used by printf-like helpers to store the bprintf binary
761  * arguments representation.
762  */
763 #define MAX_BPRINTF_BIN_ARGS	512
764 
765 /* Support executing three nested bprintf helper calls on a given CPU */
766 #define MAX_BPRINTF_NEST_LEVEL	3
767 struct bpf_bprintf_buffers {
768 	char bin_args[MAX_BPRINTF_BIN_ARGS];
769 	char buf[MAX_BPRINTF_BUF];
770 };
771 
772 static DEFINE_PER_CPU(struct bpf_bprintf_buffers[MAX_BPRINTF_NEST_LEVEL], bpf_bprintf_bufs);
773 static DEFINE_PER_CPU(int, bpf_bprintf_nest_level);
774 
775 static int try_get_buffers(struct bpf_bprintf_buffers **bufs)
776 {
777 	int nest_level;
778 
779 	preempt_disable();
780 	nest_level = this_cpu_inc_return(bpf_bprintf_nest_level);
781 	if (WARN_ON_ONCE(nest_level > MAX_BPRINTF_NEST_LEVEL)) {
782 		this_cpu_dec(bpf_bprintf_nest_level);
783 		preempt_enable();
784 		return -EBUSY;
785 	}
786 	*bufs = this_cpu_ptr(&bpf_bprintf_bufs[nest_level - 1]);
787 
788 	return 0;
789 }
790 
791 void bpf_bprintf_cleanup(struct bpf_bprintf_data *data)
792 {
793 	if (!data->bin_args && !data->buf)
794 		return;
795 	if (WARN_ON_ONCE(this_cpu_read(bpf_bprintf_nest_level) == 0))
796 		return;
797 	this_cpu_dec(bpf_bprintf_nest_level);
798 	preempt_enable();
799 }
800 
801 /*
802  * bpf_bprintf_prepare - Generic pass on format strings for bprintf-like helpers
803  *
804  * Returns a negative value if fmt is an invalid format string or 0 otherwise.
805  *
806  * This can be used in two ways:
807  * - Format string verification only: when data->get_bin_args is false
808  * - Arguments preparation: in addition to the above verification, it writes in
809  *   data->bin_args a binary representation of arguments usable by bstr_printf
810  *   where pointers from BPF have been sanitized.
811  *
812  * In argument preparation mode, if 0 is returned, safe temporary buffers are
813  * allocated and bpf_bprintf_cleanup should be called to free them after use.
814  */
815 int bpf_bprintf_prepare(char *fmt, u32 fmt_size, const u64 *raw_args,
816 			u32 num_args, struct bpf_bprintf_data *data)
817 {
818 	bool get_buffers = (data->get_bin_args && num_args) || data->get_buf;
819 	char *unsafe_ptr = NULL, *tmp_buf = NULL, *tmp_buf_end, *fmt_end;
820 	struct bpf_bprintf_buffers *buffers = NULL;
821 	size_t sizeof_cur_arg, sizeof_cur_ip;
822 	int err, i, num_spec = 0;
823 	u64 cur_arg;
824 	char fmt_ptype, cur_ip[16], ip_spec[] = "%pXX";
825 
826 	fmt_end = strnchr(fmt, fmt_size, 0);
827 	if (!fmt_end)
828 		return -EINVAL;
829 	fmt_size = fmt_end - fmt;
830 
831 	if (get_buffers && try_get_buffers(&buffers))
832 		return -EBUSY;
833 
834 	if (data->get_bin_args) {
835 		if (num_args)
836 			tmp_buf = buffers->bin_args;
837 		tmp_buf_end = tmp_buf + MAX_BPRINTF_BIN_ARGS;
838 		data->bin_args = (u32 *)tmp_buf;
839 	}
840 
841 	if (data->get_buf)
842 		data->buf = buffers->buf;
843 
844 	for (i = 0; i < fmt_size; i++) {
845 		if ((!isprint(fmt[i]) && !isspace(fmt[i])) || !isascii(fmt[i])) {
846 			err = -EINVAL;
847 			goto out;
848 		}
849 
850 		if (fmt[i] != '%')
851 			continue;
852 
853 		if (fmt[i + 1] == '%') {
854 			i++;
855 			continue;
856 		}
857 
858 		if (num_spec >= num_args) {
859 			err = -EINVAL;
860 			goto out;
861 		}
862 
863 		/* The string is zero-terminated so if fmt[i] != 0, we can
864 		 * always access fmt[i + 1], in the worst case it will be a 0
865 		 */
866 		i++;
867 
868 		/* skip optional "[0 +-][num]" width formatting field */
869 		while (fmt[i] == '0' || fmt[i] == '+'  || fmt[i] == '-' ||
870 		       fmt[i] == ' ')
871 			i++;
872 		if (fmt[i] >= '1' && fmt[i] <= '9') {
873 			i++;
874 			while (fmt[i] >= '0' && fmt[i] <= '9')
875 				i++;
876 		}
877 
878 		if (fmt[i] == 'p') {
879 			sizeof_cur_arg = sizeof(long);
880 
881 			if ((fmt[i + 1] == 'k' || fmt[i + 1] == 'u') &&
882 			    fmt[i + 2] == 's') {
883 				fmt_ptype = fmt[i + 1];
884 				i += 2;
885 				goto fmt_str;
886 			}
887 
888 			if (fmt[i + 1] == 0 || isspace(fmt[i + 1]) ||
889 			    ispunct(fmt[i + 1]) || fmt[i + 1] == 'K' ||
890 			    fmt[i + 1] == 'x' || fmt[i + 1] == 's' ||
891 			    fmt[i + 1] == 'S') {
892 				/* just kernel pointers */
893 				if (tmp_buf)
894 					cur_arg = raw_args[num_spec];
895 				i++;
896 				goto nocopy_fmt;
897 			}
898 
899 			if (fmt[i + 1] == 'B') {
900 				if (tmp_buf)  {
901 					err = snprintf(tmp_buf,
902 						       (tmp_buf_end - tmp_buf),
903 						       "%pB",
904 						       (void *)(long)raw_args[num_spec]);
905 					tmp_buf += (err + 1);
906 				}
907 
908 				i++;
909 				num_spec++;
910 				continue;
911 			}
912 
913 			/* only support "%pI4", "%pi4", "%pI6" and "%pi6". */
914 			if ((fmt[i + 1] != 'i' && fmt[i + 1] != 'I') ||
915 			    (fmt[i + 2] != '4' && fmt[i + 2] != '6')) {
916 				err = -EINVAL;
917 				goto out;
918 			}
919 
920 			i += 2;
921 			if (!tmp_buf)
922 				goto nocopy_fmt;
923 
924 			sizeof_cur_ip = (fmt[i] == '4') ? 4 : 16;
925 			if (tmp_buf_end - tmp_buf < sizeof_cur_ip) {
926 				err = -ENOSPC;
927 				goto out;
928 			}
929 
930 			unsafe_ptr = (char *)(long)raw_args[num_spec];
931 			err = copy_from_kernel_nofault(cur_ip, unsafe_ptr,
932 						       sizeof_cur_ip);
933 			if (err < 0)
934 				memset(cur_ip, 0, sizeof_cur_ip);
935 
936 			/* hack: bstr_printf expects IP addresses to be
937 			 * pre-formatted as strings, ironically, the easiest way
938 			 * to do that is to call snprintf.
939 			 */
940 			ip_spec[2] = fmt[i - 1];
941 			ip_spec[3] = fmt[i];
942 			err = snprintf(tmp_buf, tmp_buf_end - tmp_buf,
943 				       ip_spec, &cur_ip);
944 
945 			tmp_buf += err + 1;
946 			num_spec++;
947 
948 			continue;
949 		} else if (fmt[i] == 's') {
950 			fmt_ptype = fmt[i];
951 fmt_str:
952 			if (fmt[i + 1] != 0 &&
953 			    !isspace(fmt[i + 1]) &&
954 			    !ispunct(fmt[i + 1])) {
955 				err = -EINVAL;
956 				goto out;
957 			}
958 
959 			if (!tmp_buf)
960 				goto nocopy_fmt;
961 
962 			if (tmp_buf_end == tmp_buf) {
963 				err = -ENOSPC;
964 				goto out;
965 			}
966 
967 			unsafe_ptr = (char *)(long)raw_args[num_spec];
968 			err = bpf_trace_copy_string(tmp_buf, unsafe_ptr,
969 						    fmt_ptype,
970 						    tmp_buf_end - tmp_buf);
971 			if (err < 0) {
972 				tmp_buf[0] = '\0';
973 				err = 1;
974 			}
975 
976 			tmp_buf += err;
977 			num_spec++;
978 
979 			continue;
980 		} else if (fmt[i] == 'c') {
981 			if (!tmp_buf)
982 				goto nocopy_fmt;
983 
984 			if (tmp_buf_end == tmp_buf) {
985 				err = -ENOSPC;
986 				goto out;
987 			}
988 
989 			*tmp_buf = raw_args[num_spec];
990 			tmp_buf++;
991 			num_spec++;
992 
993 			continue;
994 		}
995 
996 		sizeof_cur_arg = sizeof(int);
997 
998 		if (fmt[i] == 'l') {
999 			sizeof_cur_arg = sizeof(long);
1000 			i++;
1001 		}
1002 		if (fmt[i] == 'l') {
1003 			sizeof_cur_arg = sizeof(long long);
1004 			i++;
1005 		}
1006 
1007 		if (fmt[i] != 'i' && fmt[i] != 'd' && fmt[i] != 'u' &&
1008 		    fmt[i] != 'x' && fmt[i] != 'X') {
1009 			err = -EINVAL;
1010 			goto out;
1011 		}
1012 
1013 		if (tmp_buf)
1014 			cur_arg = raw_args[num_spec];
1015 nocopy_fmt:
1016 		if (tmp_buf) {
1017 			tmp_buf = PTR_ALIGN(tmp_buf, sizeof(u32));
1018 			if (tmp_buf_end - tmp_buf < sizeof_cur_arg) {
1019 				err = -ENOSPC;
1020 				goto out;
1021 			}
1022 
1023 			if (sizeof_cur_arg == 8) {
1024 				*(u32 *)tmp_buf = *(u32 *)&cur_arg;
1025 				*(u32 *)(tmp_buf + 4) = *((u32 *)&cur_arg + 1);
1026 			} else {
1027 				*(u32 *)tmp_buf = (u32)(long)cur_arg;
1028 			}
1029 			tmp_buf += sizeof_cur_arg;
1030 		}
1031 		num_spec++;
1032 	}
1033 
1034 	err = 0;
1035 out:
1036 	if (err)
1037 		bpf_bprintf_cleanup(data);
1038 	return err;
1039 }
1040 
1041 BPF_CALL_5(bpf_snprintf, char *, str, u32, str_size, char *, fmt,
1042 	   const void *, args, u32, data_len)
1043 {
1044 	struct bpf_bprintf_data data = {
1045 		.get_bin_args	= true,
1046 	};
1047 	int err, num_args;
1048 
1049 	if (data_len % 8 || data_len > MAX_BPRINTF_VARARGS * 8 ||
1050 	    (data_len && !args))
1051 		return -EINVAL;
1052 	num_args = data_len / 8;
1053 
1054 	/* ARG_PTR_TO_CONST_STR guarantees that fmt is zero-terminated so we
1055 	 * can safely give an unbounded size.
1056 	 */
1057 	err = bpf_bprintf_prepare(fmt, UINT_MAX, args, num_args, &data);
1058 	if (err < 0)
1059 		return err;
1060 
1061 	err = bstr_printf(str, str_size, fmt, data.bin_args);
1062 
1063 	bpf_bprintf_cleanup(&data);
1064 
1065 	return err + 1;
1066 }
1067 
1068 const struct bpf_func_proto bpf_snprintf_proto = {
1069 	.func		= bpf_snprintf,
1070 	.gpl_only	= true,
1071 	.ret_type	= RET_INTEGER,
1072 	.arg1_type	= ARG_PTR_TO_MEM_OR_NULL,
1073 	.arg2_type	= ARG_CONST_SIZE_OR_ZERO,
1074 	.arg3_type	= ARG_PTR_TO_CONST_STR,
1075 	.arg4_type	= ARG_PTR_TO_MEM | PTR_MAYBE_NULL | MEM_RDONLY,
1076 	.arg5_type	= ARG_CONST_SIZE_OR_ZERO,
1077 };
1078 
1079 /* BPF map elements can contain 'struct bpf_timer'.
1080  * Such map owns all of its BPF timers.
1081  * 'struct bpf_timer' is allocated as part of map element allocation
1082  * and it's zero initialized.
1083  * That space is used to keep 'struct bpf_timer_kern'.
1084  * bpf_timer_init() allocates 'struct bpf_hrtimer', inits hrtimer, and
1085  * remembers 'struct bpf_map *' pointer it's part of.
1086  * bpf_timer_set_callback() increments prog refcnt and assign bpf callback_fn.
1087  * bpf_timer_start() arms the timer.
1088  * If user space reference to a map goes to zero at this point
1089  * ops->map_release_uref callback is responsible for cancelling the timers,
1090  * freeing their memory, and decrementing prog's refcnts.
1091  * bpf_timer_cancel() cancels the timer and decrements prog's refcnt.
1092  * Inner maps can contain bpf timers as well. ops->map_release_uref is
1093  * freeing the timers when inner map is replaced or deleted by user space.
1094  */
1095 struct bpf_hrtimer {
1096 	struct hrtimer timer;
1097 	struct bpf_map *map;
1098 	struct bpf_prog *prog;
1099 	void __rcu *callback_fn;
1100 	void *value;
1101 };
1102 
1103 /* the actual struct hidden inside uapi struct bpf_timer */
1104 struct bpf_timer_kern {
1105 	struct bpf_hrtimer *timer;
1106 	/* bpf_spin_lock is used here instead of spinlock_t to make
1107 	 * sure that it always fits into space reserved by struct bpf_timer
1108 	 * regardless of LOCKDEP and spinlock debug flags.
1109 	 */
1110 	struct bpf_spin_lock lock;
1111 } __attribute__((aligned(8)));
1112 
1113 static DEFINE_PER_CPU(struct bpf_hrtimer *, hrtimer_running);
1114 
1115 static enum hrtimer_restart bpf_timer_cb(struct hrtimer *hrtimer)
1116 {
1117 	struct bpf_hrtimer *t = container_of(hrtimer, struct bpf_hrtimer, timer);
1118 	struct bpf_map *map = t->map;
1119 	void *value = t->value;
1120 	bpf_callback_t callback_fn;
1121 	void *key;
1122 	u32 idx;
1123 
1124 	BTF_TYPE_EMIT(struct bpf_timer);
1125 	callback_fn = rcu_dereference_check(t->callback_fn, rcu_read_lock_bh_held());
1126 	if (!callback_fn)
1127 		goto out;
1128 
1129 	/* bpf_timer_cb() runs in hrtimer_run_softirq. It doesn't migrate and
1130 	 * cannot be preempted by another bpf_timer_cb() on the same cpu.
1131 	 * Remember the timer this callback is servicing to prevent
1132 	 * deadlock if callback_fn() calls bpf_timer_cancel() or
1133 	 * bpf_map_delete_elem() on the same timer.
1134 	 */
1135 	this_cpu_write(hrtimer_running, t);
1136 	if (map->map_type == BPF_MAP_TYPE_ARRAY) {
1137 		struct bpf_array *array = container_of(map, struct bpf_array, map);
1138 
1139 		/* compute the key */
1140 		idx = ((char *)value - array->value) / array->elem_size;
1141 		key = &idx;
1142 	} else { /* hash or lru */
1143 		key = value - round_up(map->key_size, 8);
1144 	}
1145 
1146 	callback_fn((u64)(long)map, (u64)(long)key, (u64)(long)value, 0, 0);
1147 	/* The verifier checked that return value is zero. */
1148 
1149 	this_cpu_write(hrtimer_running, NULL);
1150 out:
1151 	return HRTIMER_NORESTART;
1152 }
1153 
1154 BPF_CALL_3(bpf_timer_init, struct bpf_timer_kern *, timer, struct bpf_map *, map,
1155 	   u64, flags)
1156 {
1157 	clockid_t clockid = flags & (MAX_CLOCKS - 1);
1158 	struct bpf_hrtimer *t;
1159 	int ret = 0;
1160 
1161 	BUILD_BUG_ON(MAX_CLOCKS != 16);
1162 	BUILD_BUG_ON(sizeof(struct bpf_timer_kern) > sizeof(struct bpf_timer));
1163 	BUILD_BUG_ON(__alignof__(struct bpf_timer_kern) != __alignof__(struct bpf_timer));
1164 
1165 	if (in_nmi())
1166 		return -EOPNOTSUPP;
1167 
1168 	if (flags >= MAX_CLOCKS ||
1169 	    /* similar to timerfd except _ALARM variants are not supported */
1170 	    (clockid != CLOCK_MONOTONIC &&
1171 	     clockid != CLOCK_REALTIME &&
1172 	     clockid != CLOCK_BOOTTIME))
1173 		return -EINVAL;
1174 	__bpf_spin_lock_irqsave(&timer->lock);
1175 	t = timer->timer;
1176 	if (t) {
1177 		ret = -EBUSY;
1178 		goto out;
1179 	}
1180 	/* allocate hrtimer via map_kmalloc to use memcg accounting */
1181 	t = bpf_map_kmalloc_node(map, sizeof(*t), GFP_ATOMIC, map->numa_node);
1182 	if (!t) {
1183 		ret = -ENOMEM;
1184 		goto out;
1185 	}
1186 	t->value = (void *)timer - map->record->timer_off;
1187 	t->map = map;
1188 	t->prog = NULL;
1189 	rcu_assign_pointer(t->callback_fn, NULL);
1190 	hrtimer_init(&t->timer, clockid, HRTIMER_MODE_REL_SOFT);
1191 	t->timer.function = bpf_timer_cb;
1192 	WRITE_ONCE(timer->timer, t);
1193 	/* Guarantee the order between timer->timer and map->usercnt. So
1194 	 * when there are concurrent uref release and bpf timer init, either
1195 	 * bpf_timer_cancel_and_free() called by uref release reads a no-NULL
1196 	 * timer or atomic64_read() below returns a zero usercnt.
1197 	 */
1198 	smp_mb();
1199 	if (!atomic64_read(&map->usercnt)) {
1200 		/* maps with timers must be either held by user space
1201 		 * or pinned in bpffs.
1202 		 */
1203 		WRITE_ONCE(timer->timer, NULL);
1204 		kfree(t);
1205 		ret = -EPERM;
1206 	}
1207 out:
1208 	__bpf_spin_unlock_irqrestore(&timer->lock);
1209 	return ret;
1210 }
1211 
1212 static const struct bpf_func_proto bpf_timer_init_proto = {
1213 	.func		= bpf_timer_init,
1214 	.gpl_only	= true,
1215 	.ret_type	= RET_INTEGER,
1216 	.arg1_type	= ARG_PTR_TO_TIMER,
1217 	.arg2_type	= ARG_CONST_MAP_PTR,
1218 	.arg3_type	= ARG_ANYTHING,
1219 };
1220 
1221 BPF_CALL_3(bpf_timer_set_callback, struct bpf_timer_kern *, timer, void *, callback_fn,
1222 	   struct bpf_prog_aux *, aux)
1223 {
1224 	struct bpf_prog *prev, *prog = aux->prog;
1225 	struct bpf_hrtimer *t;
1226 	int ret = 0;
1227 
1228 	if (in_nmi())
1229 		return -EOPNOTSUPP;
1230 	__bpf_spin_lock_irqsave(&timer->lock);
1231 	t = timer->timer;
1232 	if (!t) {
1233 		ret = -EINVAL;
1234 		goto out;
1235 	}
1236 	if (!atomic64_read(&t->map->usercnt)) {
1237 		/* maps with timers must be either held by user space
1238 		 * or pinned in bpffs. Otherwise timer might still be
1239 		 * running even when bpf prog is detached and user space
1240 		 * is gone, since map_release_uref won't ever be called.
1241 		 */
1242 		ret = -EPERM;
1243 		goto out;
1244 	}
1245 	prev = t->prog;
1246 	if (prev != prog) {
1247 		/* Bump prog refcnt once. Every bpf_timer_set_callback()
1248 		 * can pick different callback_fn-s within the same prog.
1249 		 */
1250 		prog = bpf_prog_inc_not_zero(prog);
1251 		if (IS_ERR(prog)) {
1252 			ret = PTR_ERR(prog);
1253 			goto out;
1254 		}
1255 		if (prev)
1256 			/* Drop prev prog refcnt when swapping with new prog */
1257 			bpf_prog_put(prev);
1258 		t->prog = prog;
1259 	}
1260 	rcu_assign_pointer(t->callback_fn, callback_fn);
1261 out:
1262 	__bpf_spin_unlock_irqrestore(&timer->lock);
1263 	return ret;
1264 }
1265 
1266 static const struct bpf_func_proto bpf_timer_set_callback_proto = {
1267 	.func		= bpf_timer_set_callback,
1268 	.gpl_only	= true,
1269 	.ret_type	= RET_INTEGER,
1270 	.arg1_type	= ARG_PTR_TO_TIMER,
1271 	.arg2_type	= ARG_PTR_TO_FUNC,
1272 };
1273 
1274 BPF_CALL_3(bpf_timer_start, struct bpf_timer_kern *, timer, u64, nsecs, u64, flags)
1275 {
1276 	struct bpf_hrtimer *t;
1277 	int ret = 0;
1278 	enum hrtimer_mode mode;
1279 
1280 	if (in_nmi())
1281 		return -EOPNOTSUPP;
1282 	if (flags & ~(BPF_F_TIMER_ABS | BPF_F_TIMER_CPU_PIN))
1283 		return -EINVAL;
1284 	__bpf_spin_lock_irqsave(&timer->lock);
1285 	t = timer->timer;
1286 	if (!t || !t->prog) {
1287 		ret = -EINVAL;
1288 		goto out;
1289 	}
1290 
1291 	if (flags & BPF_F_TIMER_ABS)
1292 		mode = HRTIMER_MODE_ABS_SOFT;
1293 	else
1294 		mode = HRTIMER_MODE_REL_SOFT;
1295 
1296 	if (flags & BPF_F_TIMER_CPU_PIN)
1297 		mode |= HRTIMER_MODE_PINNED;
1298 
1299 	hrtimer_start(&t->timer, ns_to_ktime(nsecs), mode);
1300 out:
1301 	__bpf_spin_unlock_irqrestore(&timer->lock);
1302 	return ret;
1303 }
1304 
1305 static const struct bpf_func_proto bpf_timer_start_proto = {
1306 	.func		= bpf_timer_start,
1307 	.gpl_only	= true,
1308 	.ret_type	= RET_INTEGER,
1309 	.arg1_type	= ARG_PTR_TO_TIMER,
1310 	.arg2_type	= ARG_ANYTHING,
1311 	.arg3_type	= ARG_ANYTHING,
1312 };
1313 
1314 static void drop_prog_refcnt(struct bpf_hrtimer *t)
1315 {
1316 	struct bpf_prog *prog = t->prog;
1317 
1318 	if (prog) {
1319 		bpf_prog_put(prog);
1320 		t->prog = NULL;
1321 		rcu_assign_pointer(t->callback_fn, NULL);
1322 	}
1323 }
1324 
1325 BPF_CALL_1(bpf_timer_cancel, struct bpf_timer_kern *, timer)
1326 {
1327 	struct bpf_hrtimer *t;
1328 	int ret = 0;
1329 
1330 	if (in_nmi())
1331 		return -EOPNOTSUPP;
1332 	__bpf_spin_lock_irqsave(&timer->lock);
1333 	t = timer->timer;
1334 	if (!t) {
1335 		ret = -EINVAL;
1336 		goto out;
1337 	}
1338 	if (this_cpu_read(hrtimer_running) == t) {
1339 		/* If bpf callback_fn is trying to bpf_timer_cancel()
1340 		 * its own timer the hrtimer_cancel() will deadlock
1341 		 * since it waits for callback_fn to finish
1342 		 */
1343 		ret = -EDEADLK;
1344 		goto out;
1345 	}
1346 	drop_prog_refcnt(t);
1347 out:
1348 	__bpf_spin_unlock_irqrestore(&timer->lock);
1349 	/* Cancel the timer and wait for associated callback to finish
1350 	 * if it was running.
1351 	 */
1352 	ret = ret ?: hrtimer_cancel(&t->timer);
1353 	return ret;
1354 }
1355 
1356 static const struct bpf_func_proto bpf_timer_cancel_proto = {
1357 	.func		= bpf_timer_cancel,
1358 	.gpl_only	= true,
1359 	.ret_type	= RET_INTEGER,
1360 	.arg1_type	= ARG_PTR_TO_TIMER,
1361 };
1362 
1363 /* This function is called by map_delete/update_elem for individual element and
1364  * by ops->map_release_uref when the user space reference to a map reaches zero.
1365  */
1366 void bpf_timer_cancel_and_free(void *val)
1367 {
1368 	struct bpf_timer_kern *timer = val;
1369 	struct bpf_hrtimer *t;
1370 
1371 	/* Performance optimization: read timer->timer without lock first. */
1372 	if (!READ_ONCE(timer->timer))
1373 		return;
1374 
1375 	__bpf_spin_lock_irqsave(&timer->lock);
1376 	/* re-read it under lock */
1377 	t = timer->timer;
1378 	if (!t)
1379 		goto out;
1380 	drop_prog_refcnt(t);
1381 	/* The subsequent bpf_timer_start/cancel() helpers won't be able to use
1382 	 * this timer, since it won't be initialized.
1383 	 */
1384 	WRITE_ONCE(timer->timer, NULL);
1385 out:
1386 	__bpf_spin_unlock_irqrestore(&timer->lock);
1387 	if (!t)
1388 		return;
1389 	/* Cancel the timer and wait for callback to complete if it was running.
1390 	 * If hrtimer_cancel() can be safely called it's safe to call kfree(t)
1391 	 * right after for both preallocated and non-preallocated maps.
1392 	 * The timer->timer = NULL was already done and no code path can
1393 	 * see address 't' anymore.
1394 	 *
1395 	 * Check that bpf_map_delete/update_elem() wasn't called from timer
1396 	 * callback_fn. In such case don't call hrtimer_cancel() (since it will
1397 	 * deadlock) and don't call hrtimer_try_to_cancel() (since it will just
1398 	 * return -1). Though callback_fn is still running on this cpu it's
1399 	 * safe to do kfree(t) because bpf_timer_cb() read everything it needed
1400 	 * from 't'. The bpf subprog callback_fn won't be able to access 't',
1401 	 * since timer->timer = NULL was already done. The timer will be
1402 	 * effectively cancelled because bpf_timer_cb() will return
1403 	 * HRTIMER_NORESTART.
1404 	 */
1405 	if (this_cpu_read(hrtimer_running) != t)
1406 		hrtimer_cancel(&t->timer);
1407 	kfree(t);
1408 }
1409 
1410 BPF_CALL_2(bpf_kptr_xchg, void *, map_value, void *, ptr)
1411 {
1412 	unsigned long *kptr = map_value;
1413 
1414 	return xchg(kptr, (unsigned long)ptr);
1415 }
1416 
1417 /* Unlike other PTR_TO_BTF_ID helpers the btf_id in bpf_kptr_xchg()
1418  * helper is determined dynamically by the verifier. Use BPF_PTR_POISON to
1419  * denote type that verifier will determine.
1420  */
1421 static const struct bpf_func_proto bpf_kptr_xchg_proto = {
1422 	.func         = bpf_kptr_xchg,
1423 	.gpl_only     = false,
1424 	.ret_type     = RET_PTR_TO_BTF_ID_OR_NULL,
1425 	.ret_btf_id   = BPF_PTR_POISON,
1426 	.arg1_type    = ARG_PTR_TO_KPTR,
1427 	.arg2_type    = ARG_PTR_TO_BTF_ID_OR_NULL | OBJ_RELEASE,
1428 	.arg2_btf_id  = BPF_PTR_POISON,
1429 };
1430 
1431 /* Since the upper 8 bits of dynptr->size is reserved, the
1432  * maximum supported size is 2^24 - 1.
1433  */
1434 #define DYNPTR_MAX_SIZE	((1UL << 24) - 1)
1435 #define DYNPTR_TYPE_SHIFT	28
1436 #define DYNPTR_SIZE_MASK	0xFFFFFF
1437 #define DYNPTR_RDONLY_BIT	BIT(31)
1438 
1439 static bool __bpf_dynptr_is_rdonly(const struct bpf_dynptr_kern *ptr)
1440 {
1441 	return ptr->size & DYNPTR_RDONLY_BIT;
1442 }
1443 
1444 void bpf_dynptr_set_rdonly(struct bpf_dynptr_kern *ptr)
1445 {
1446 	ptr->size |= DYNPTR_RDONLY_BIT;
1447 }
1448 
1449 static void bpf_dynptr_set_type(struct bpf_dynptr_kern *ptr, enum bpf_dynptr_type type)
1450 {
1451 	ptr->size |= type << DYNPTR_TYPE_SHIFT;
1452 }
1453 
1454 static enum bpf_dynptr_type bpf_dynptr_get_type(const struct bpf_dynptr_kern *ptr)
1455 {
1456 	return (ptr->size & ~(DYNPTR_RDONLY_BIT)) >> DYNPTR_TYPE_SHIFT;
1457 }
1458 
1459 u32 __bpf_dynptr_size(const struct bpf_dynptr_kern *ptr)
1460 {
1461 	return ptr->size & DYNPTR_SIZE_MASK;
1462 }
1463 
1464 static void bpf_dynptr_set_size(struct bpf_dynptr_kern *ptr, u32 new_size)
1465 {
1466 	u32 metadata = ptr->size & ~DYNPTR_SIZE_MASK;
1467 
1468 	ptr->size = new_size | metadata;
1469 }
1470 
1471 int bpf_dynptr_check_size(u32 size)
1472 {
1473 	return size > DYNPTR_MAX_SIZE ? -E2BIG : 0;
1474 }
1475 
1476 void bpf_dynptr_init(struct bpf_dynptr_kern *ptr, void *data,
1477 		     enum bpf_dynptr_type type, u32 offset, u32 size)
1478 {
1479 	ptr->data = data;
1480 	ptr->offset = offset;
1481 	ptr->size = size;
1482 	bpf_dynptr_set_type(ptr, type);
1483 }
1484 
1485 void bpf_dynptr_set_null(struct bpf_dynptr_kern *ptr)
1486 {
1487 	memset(ptr, 0, sizeof(*ptr));
1488 }
1489 
1490 static int bpf_dynptr_check_off_len(const struct bpf_dynptr_kern *ptr, u32 offset, u32 len)
1491 {
1492 	u32 size = __bpf_dynptr_size(ptr);
1493 
1494 	if (len > size || offset > size - len)
1495 		return -E2BIG;
1496 
1497 	return 0;
1498 }
1499 
1500 BPF_CALL_4(bpf_dynptr_from_mem, void *, data, u32, size, u64, flags, struct bpf_dynptr_kern *, ptr)
1501 {
1502 	int err;
1503 
1504 	BTF_TYPE_EMIT(struct bpf_dynptr);
1505 
1506 	err = bpf_dynptr_check_size(size);
1507 	if (err)
1508 		goto error;
1509 
1510 	/* flags is currently unsupported */
1511 	if (flags) {
1512 		err = -EINVAL;
1513 		goto error;
1514 	}
1515 
1516 	bpf_dynptr_init(ptr, data, BPF_DYNPTR_TYPE_LOCAL, 0, size);
1517 
1518 	return 0;
1519 
1520 error:
1521 	bpf_dynptr_set_null(ptr);
1522 	return err;
1523 }
1524 
1525 static const struct bpf_func_proto bpf_dynptr_from_mem_proto = {
1526 	.func		= bpf_dynptr_from_mem,
1527 	.gpl_only	= false,
1528 	.ret_type	= RET_INTEGER,
1529 	.arg1_type	= ARG_PTR_TO_UNINIT_MEM,
1530 	.arg2_type	= ARG_CONST_SIZE_OR_ZERO,
1531 	.arg3_type	= ARG_ANYTHING,
1532 	.arg4_type	= ARG_PTR_TO_DYNPTR | DYNPTR_TYPE_LOCAL | MEM_UNINIT,
1533 };
1534 
1535 BPF_CALL_5(bpf_dynptr_read, void *, dst, u32, len, const struct bpf_dynptr_kern *, src,
1536 	   u32, offset, u64, flags)
1537 {
1538 	enum bpf_dynptr_type type;
1539 	int err;
1540 
1541 	if (!src->data || flags)
1542 		return -EINVAL;
1543 
1544 	err = bpf_dynptr_check_off_len(src, offset, len);
1545 	if (err)
1546 		return err;
1547 
1548 	type = bpf_dynptr_get_type(src);
1549 
1550 	switch (type) {
1551 	case BPF_DYNPTR_TYPE_LOCAL:
1552 	case BPF_DYNPTR_TYPE_RINGBUF:
1553 		/* Source and destination may possibly overlap, hence use memmove to
1554 		 * copy the data. E.g. bpf_dynptr_from_mem may create two dynptr
1555 		 * pointing to overlapping PTR_TO_MAP_VALUE regions.
1556 		 */
1557 		memmove(dst, src->data + src->offset + offset, len);
1558 		return 0;
1559 	case BPF_DYNPTR_TYPE_SKB:
1560 		return __bpf_skb_load_bytes(src->data, src->offset + offset, dst, len);
1561 	case BPF_DYNPTR_TYPE_XDP:
1562 		return __bpf_xdp_load_bytes(src->data, src->offset + offset, dst, len);
1563 	default:
1564 		WARN_ONCE(true, "bpf_dynptr_read: unknown dynptr type %d\n", type);
1565 		return -EFAULT;
1566 	}
1567 }
1568 
1569 static const struct bpf_func_proto bpf_dynptr_read_proto = {
1570 	.func		= bpf_dynptr_read,
1571 	.gpl_only	= false,
1572 	.ret_type	= RET_INTEGER,
1573 	.arg1_type	= ARG_PTR_TO_UNINIT_MEM,
1574 	.arg2_type	= ARG_CONST_SIZE_OR_ZERO,
1575 	.arg3_type	= ARG_PTR_TO_DYNPTR | MEM_RDONLY,
1576 	.arg4_type	= ARG_ANYTHING,
1577 	.arg5_type	= ARG_ANYTHING,
1578 };
1579 
1580 BPF_CALL_5(bpf_dynptr_write, const struct bpf_dynptr_kern *, dst, u32, offset, void *, src,
1581 	   u32, len, u64, flags)
1582 {
1583 	enum bpf_dynptr_type type;
1584 	int err;
1585 
1586 	if (!dst->data || __bpf_dynptr_is_rdonly(dst))
1587 		return -EINVAL;
1588 
1589 	err = bpf_dynptr_check_off_len(dst, offset, len);
1590 	if (err)
1591 		return err;
1592 
1593 	type = bpf_dynptr_get_type(dst);
1594 
1595 	switch (type) {
1596 	case BPF_DYNPTR_TYPE_LOCAL:
1597 	case BPF_DYNPTR_TYPE_RINGBUF:
1598 		if (flags)
1599 			return -EINVAL;
1600 		/* Source and destination may possibly overlap, hence use memmove to
1601 		 * copy the data. E.g. bpf_dynptr_from_mem may create two dynptr
1602 		 * pointing to overlapping PTR_TO_MAP_VALUE regions.
1603 		 */
1604 		memmove(dst->data + dst->offset + offset, src, len);
1605 		return 0;
1606 	case BPF_DYNPTR_TYPE_SKB:
1607 		return __bpf_skb_store_bytes(dst->data, dst->offset + offset, src, len,
1608 					     flags);
1609 	case BPF_DYNPTR_TYPE_XDP:
1610 		if (flags)
1611 			return -EINVAL;
1612 		return __bpf_xdp_store_bytes(dst->data, dst->offset + offset, src, len);
1613 	default:
1614 		WARN_ONCE(true, "bpf_dynptr_write: unknown dynptr type %d\n", type);
1615 		return -EFAULT;
1616 	}
1617 }
1618 
1619 static const struct bpf_func_proto bpf_dynptr_write_proto = {
1620 	.func		= bpf_dynptr_write,
1621 	.gpl_only	= false,
1622 	.ret_type	= RET_INTEGER,
1623 	.arg1_type	= ARG_PTR_TO_DYNPTR | MEM_RDONLY,
1624 	.arg2_type	= ARG_ANYTHING,
1625 	.arg3_type	= ARG_PTR_TO_MEM | MEM_RDONLY,
1626 	.arg4_type	= ARG_CONST_SIZE_OR_ZERO,
1627 	.arg5_type	= ARG_ANYTHING,
1628 };
1629 
1630 BPF_CALL_3(bpf_dynptr_data, const struct bpf_dynptr_kern *, ptr, u32, offset, u32, len)
1631 {
1632 	enum bpf_dynptr_type type;
1633 	int err;
1634 
1635 	if (!ptr->data)
1636 		return 0;
1637 
1638 	err = bpf_dynptr_check_off_len(ptr, offset, len);
1639 	if (err)
1640 		return 0;
1641 
1642 	if (__bpf_dynptr_is_rdonly(ptr))
1643 		return 0;
1644 
1645 	type = bpf_dynptr_get_type(ptr);
1646 
1647 	switch (type) {
1648 	case BPF_DYNPTR_TYPE_LOCAL:
1649 	case BPF_DYNPTR_TYPE_RINGBUF:
1650 		return (unsigned long)(ptr->data + ptr->offset + offset);
1651 	case BPF_DYNPTR_TYPE_SKB:
1652 	case BPF_DYNPTR_TYPE_XDP:
1653 		/* skb and xdp dynptrs should use bpf_dynptr_slice / bpf_dynptr_slice_rdwr */
1654 		return 0;
1655 	default:
1656 		WARN_ONCE(true, "bpf_dynptr_data: unknown dynptr type %d\n", type);
1657 		return 0;
1658 	}
1659 }
1660 
1661 static const struct bpf_func_proto bpf_dynptr_data_proto = {
1662 	.func		= bpf_dynptr_data,
1663 	.gpl_only	= false,
1664 	.ret_type	= RET_PTR_TO_DYNPTR_MEM_OR_NULL,
1665 	.arg1_type	= ARG_PTR_TO_DYNPTR | MEM_RDONLY,
1666 	.arg2_type	= ARG_ANYTHING,
1667 	.arg3_type	= ARG_CONST_ALLOC_SIZE_OR_ZERO,
1668 };
1669 
1670 const struct bpf_func_proto bpf_get_current_task_proto __weak;
1671 const struct bpf_func_proto bpf_get_current_task_btf_proto __weak;
1672 const struct bpf_func_proto bpf_probe_read_user_proto __weak;
1673 const struct bpf_func_proto bpf_probe_read_user_str_proto __weak;
1674 const struct bpf_func_proto bpf_probe_read_kernel_proto __weak;
1675 const struct bpf_func_proto bpf_probe_read_kernel_str_proto __weak;
1676 const struct bpf_func_proto bpf_task_pt_regs_proto __weak;
1677 
1678 const struct bpf_func_proto *
1679 bpf_base_func_proto(enum bpf_func_id func_id)
1680 {
1681 	switch (func_id) {
1682 	case BPF_FUNC_map_lookup_elem:
1683 		return &bpf_map_lookup_elem_proto;
1684 	case BPF_FUNC_map_update_elem:
1685 		return &bpf_map_update_elem_proto;
1686 	case BPF_FUNC_map_delete_elem:
1687 		return &bpf_map_delete_elem_proto;
1688 	case BPF_FUNC_map_push_elem:
1689 		return &bpf_map_push_elem_proto;
1690 	case BPF_FUNC_map_pop_elem:
1691 		return &bpf_map_pop_elem_proto;
1692 	case BPF_FUNC_map_peek_elem:
1693 		return &bpf_map_peek_elem_proto;
1694 	case BPF_FUNC_map_lookup_percpu_elem:
1695 		return &bpf_map_lookup_percpu_elem_proto;
1696 	case BPF_FUNC_get_prandom_u32:
1697 		return &bpf_get_prandom_u32_proto;
1698 	case BPF_FUNC_get_smp_processor_id:
1699 		return &bpf_get_raw_smp_processor_id_proto;
1700 	case BPF_FUNC_get_numa_node_id:
1701 		return &bpf_get_numa_node_id_proto;
1702 	case BPF_FUNC_tail_call:
1703 		return &bpf_tail_call_proto;
1704 	case BPF_FUNC_ktime_get_ns:
1705 		return &bpf_ktime_get_ns_proto;
1706 	case BPF_FUNC_ktime_get_boot_ns:
1707 		return &bpf_ktime_get_boot_ns_proto;
1708 	case BPF_FUNC_ktime_get_tai_ns:
1709 		return &bpf_ktime_get_tai_ns_proto;
1710 	case BPF_FUNC_ringbuf_output:
1711 		return &bpf_ringbuf_output_proto;
1712 	case BPF_FUNC_ringbuf_reserve:
1713 		return &bpf_ringbuf_reserve_proto;
1714 	case BPF_FUNC_ringbuf_submit:
1715 		return &bpf_ringbuf_submit_proto;
1716 	case BPF_FUNC_ringbuf_discard:
1717 		return &bpf_ringbuf_discard_proto;
1718 	case BPF_FUNC_ringbuf_query:
1719 		return &bpf_ringbuf_query_proto;
1720 	case BPF_FUNC_strncmp:
1721 		return &bpf_strncmp_proto;
1722 	case BPF_FUNC_strtol:
1723 		return &bpf_strtol_proto;
1724 	case BPF_FUNC_strtoul:
1725 		return &bpf_strtoul_proto;
1726 	default:
1727 		break;
1728 	}
1729 
1730 	if (!bpf_capable())
1731 		return NULL;
1732 
1733 	switch (func_id) {
1734 	case BPF_FUNC_spin_lock:
1735 		return &bpf_spin_lock_proto;
1736 	case BPF_FUNC_spin_unlock:
1737 		return &bpf_spin_unlock_proto;
1738 	case BPF_FUNC_jiffies64:
1739 		return &bpf_jiffies64_proto;
1740 	case BPF_FUNC_per_cpu_ptr:
1741 		return &bpf_per_cpu_ptr_proto;
1742 	case BPF_FUNC_this_cpu_ptr:
1743 		return &bpf_this_cpu_ptr_proto;
1744 	case BPF_FUNC_timer_init:
1745 		return &bpf_timer_init_proto;
1746 	case BPF_FUNC_timer_set_callback:
1747 		return &bpf_timer_set_callback_proto;
1748 	case BPF_FUNC_timer_start:
1749 		return &bpf_timer_start_proto;
1750 	case BPF_FUNC_timer_cancel:
1751 		return &bpf_timer_cancel_proto;
1752 	case BPF_FUNC_kptr_xchg:
1753 		return &bpf_kptr_xchg_proto;
1754 	case BPF_FUNC_for_each_map_elem:
1755 		return &bpf_for_each_map_elem_proto;
1756 	case BPF_FUNC_loop:
1757 		return &bpf_loop_proto;
1758 	case BPF_FUNC_user_ringbuf_drain:
1759 		return &bpf_user_ringbuf_drain_proto;
1760 	case BPF_FUNC_ringbuf_reserve_dynptr:
1761 		return &bpf_ringbuf_reserve_dynptr_proto;
1762 	case BPF_FUNC_ringbuf_submit_dynptr:
1763 		return &bpf_ringbuf_submit_dynptr_proto;
1764 	case BPF_FUNC_ringbuf_discard_dynptr:
1765 		return &bpf_ringbuf_discard_dynptr_proto;
1766 	case BPF_FUNC_dynptr_from_mem:
1767 		return &bpf_dynptr_from_mem_proto;
1768 	case BPF_FUNC_dynptr_read:
1769 		return &bpf_dynptr_read_proto;
1770 	case BPF_FUNC_dynptr_write:
1771 		return &bpf_dynptr_write_proto;
1772 	case BPF_FUNC_dynptr_data:
1773 		return &bpf_dynptr_data_proto;
1774 #ifdef CONFIG_CGROUPS
1775 	case BPF_FUNC_cgrp_storage_get:
1776 		return &bpf_cgrp_storage_get_proto;
1777 	case BPF_FUNC_cgrp_storage_delete:
1778 		return &bpf_cgrp_storage_delete_proto;
1779 	case BPF_FUNC_get_current_cgroup_id:
1780 		return &bpf_get_current_cgroup_id_proto;
1781 	case BPF_FUNC_get_current_ancestor_cgroup_id:
1782 		return &bpf_get_current_ancestor_cgroup_id_proto;
1783 #endif
1784 	default:
1785 		break;
1786 	}
1787 
1788 	if (!perfmon_capable())
1789 		return NULL;
1790 
1791 	switch (func_id) {
1792 	case BPF_FUNC_trace_printk:
1793 		return bpf_get_trace_printk_proto();
1794 	case BPF_FUNC_get_current_task:
1795 		return &bpf_get_current_task_proto;
1796 	case BPF_FUNC_get_current_task_btf:
1797 		return &bpf_get_current_task_btf_proto;
1798 	case BPF_FUNC_probe_read_user:
1799 		return &bpf_probe_read_user_proto;
1800 	case BPF_FUNC_probe_read_kernel:
1801 		return security_locked_down(LOCKDOWN_BPF_READ_KERNEL) < 0 ?
1802 		       NULL : &bpf_probe_read_kernel_proto;
1803 	case BPF_FUNC_probe_read_user_str:
1804 		return &bpf_probe_read_user_str_proto;
1805 	case BPF_FUNC_probe_read_kernel_str:
1806 		return security_locked_down(LOCKDOWN_BPF_READ_KERNEL) < 0 ?
1807 		       NULL : &bpf_probe_read_kernel_str_proto;
1808 	case BPF_FUNC_snprintf_btf:
1809 		return &bpf_snprintf_btf_proto;
1810 	case BPF_FUNC_snprintf:
1811 		return &bpf_snprintf_proto;
1812 	case BPF_FUNC_task_pt_regs:
1813 		return &bpf_task_pt_regs_proto;
1814 	case BPF_FUNC_trace_vprintk:
1815 		return bpf_get_trace_vprintk_proto();
1816 	default:
1817 		return NULL;
1818 	}
1819 }
1820 
1821 void bpf_list_head_free(const struct btf_field *field, void *list_head,
1822 			struct bpf_spin_lock *spin_lock)
1823 {
1824 	struct list_head *head = list_head, *orig_head = list_head;
1825 
1826 	BUILD_BUG_ON(sizeof(struct list_head) > sizeof(struct bpf_list_head));
1827 	BUILD_BUG_ON(__alignof__(struct list_head) > __alignof__(struct bpf_list_head));
1828 
1829 	/* Do the actual list draining outside the lock to not hold the lock for
1830 	 * too long, and also prevent deadlocks if tracing programs end up
1831 	 * executing on entry/exit of functions called inside the critical
1832 	 * section, and end up doing map ops that call bpf_list_head_free for
1833 	 * the same map value again.
1834 	 */
1835 	__bpf_spin_lock_irqsave(spin_lock);
1836 	if (!head->next || list_empty(head))
1837 		goto unlock;
1838 	head = head->next;
1839 unlock:
1840 	INIT_LIST_HEAD(orig_head);
1841 	__bpf_spin_unlock_irqrestore(spin_lock);
1842 
1843 	while (head != orig_head) {
1844 		void *obj = head;
1845 
1846 		obj -= field->graph_root.node_offset;
1847 		head = head->next;
1848 		/* The contained type can also have resources, including a
1849 		 * bpf_list_head which needs to be freed.
1850 		 */
1851 		migrate_disable();
1852 		__bpf_obj_drop_impl(obj, field->graph_root.value_rec, false);
1853 		migrate_enable();
1854 	}
1855 }
1856 
1857 /* Like rbtree_postorder_for_each_entry_safe, but 'pos' and 'n' are
1858  * 'rb_node *', so field name of rb_node within containing struct is not
1859  * needed.
1860  *
1861  * Since bpf_rb_tree's node type has a corresponding struct btf_field with
1862  * graph_root.node_offset, it's not necessary to know field name
1863  * or type of node struct
1864  */
1865 #define bpf_rbtree_postorder_for_each_entry_safe(pos, n, root) \
1866 	for (pos = rb_first_postorder(root); \
1867 	    pos && ({ n = rb_next_postorder(pos); 1; }); \
1868 	    pos = n)
1869 
1870 void bpf_rb_root_free(const struct btf_field *field, void *rb_root,
1871 		      struct bpf_spin_lock *spin_lock)
1872 {
1873 	struct rb_root_cached orig_root, *root = rb_root;
1874 	struct rb_node *pos, *n;
1875 	void *obj;
1876 
1877 	BUILD_BUG_ON(sizeof(struct rb_root_cached) > sizeof(struct bpf_rb_root));
1878 	BUILD_BUG_ON(__alignof__(struct rb_root_cached) > __alignof__(struct bpf_rb_root));
1879 
1880 	__bpf_spin_lock_irqsave(spin_lock);
1881 	orig_root = *root;
1882 	*root = RB_ROOT_CACHED;
1883 	__bpf_spin_unlock_irqrestore(spin_lock);
1884 
1885 	bpf_rbtree_postorder_for_each_entry_safe(pos, n, &orig_root.rb_root) {
1886 		obj = pos;
1887 		obj -= field->graph_root.node_offset;
1888 
1889 
1890 		migrate_disable();
1891 		__bpf_obj_drop_impl(obj, field->graph_root.value_rec, false);
1892 		migrate_enable();
1893 	}
1894 }
1895 
1896 __bpf_kfunc_start_defs();
1897 
1898 __bpf_kfunc void *bpf_obj_new_impl(u64 local_type_id__k, void *meta__ign)
1899 {
1900 	struct btf_struct_meta *meta = meta__ign;
1901 	u64 size = local_type_id__k;
1902 	void *p;
1903 
1904 	p = bpf_mem_alloc(&bpf_global_ma, size);
1905 	if (!p)
1906 		return NULL;
1907 	if (meta)
1908 		bpf_obj_init(meta->record, p);
1909 	return p;
1910 }
1911 
1912 __bpf_kfunc void *bpf_percpu_obj_new_impl(u64 local_type_id__k, void *meta__ign)
1913 {
1914 	u64 size = local_type_id__k;
1915 
1916 	/* The verifier has ensured that meta__ign must be NULL */
1917 	return bpf_mem_alloc(&bpf_global_percpu_ma, size);
1918 }
1919 
1920 /* Must be called under migrate_disable(), as required by bpf_mem_free */
1921 void __bpf_obj_drop_impl(void *p, const struct btf_record *rec, bool percpu)
1922 {
1923 	struct bpf_mem_alloc *ma;
1924 
1925 	if (rec && rec->refcount_off >= 0 &&
1926 	    !refcount_dec_and_test((refcount_t *)(p + rec->refcount_off))) {
1927 		/* Object is refcounted and refcount_dec didn't result in 0
1928 		 * refcount. Return without freeing the object
1929 		 */
1930 		return;
1931 	}
1932 
1933 	if (rec)
1934 		bpf_obj_free_fields(rec, p);
1935 
1936 	if (percpu)
1937 		ma = &bpf_global_percpu_ma;
1938 	else
1939 		ma = &bpf_global_ma;
1940 	if (rec && rec->refcount_off >= 0)
1941 		bpf_mem_free_rcu(ma, p);
1942 	else
1943 		bpf_mem_free(ma, p);
1944 }
1945 
1946 __bpf_kfunc void bpf_obj_drop_impl(void *p__alloc, void *meta__ign)
1947 {
1948 	struct btf_struct_meta *meta = meta__ign;
1949 	void *p = p__alloc;
1950 
1951 	__bpf_obj_drop_impl(p, meta ? meta->record : NULL, false);
1952 }
1953 
1954 __bpf_kfunc void bpf_percpu_obj_drop_impl(void *p__alloc, void *meta__ign)
1955 {
1956 	/* The verifier has ensured that meta__ign must be NULL */
1957 	bpf_mem_free_rcu(&bpf_global_percpu_ma, p__alloc);
1958 }
1959 
1960 __bpf_kfunc void *bpf_refcount_acquire_impl(void *p__refcounted_kptr, void *meta__ign)
1961 {
1962 	struct btf_struct_meta *meta = meta__ign;
1963 	struct bpf_refcount *ref;
1964 
1965 	/* Could just cast directly to refcount_t *, but need some code using
1966 	 * bpf_refcount type so that it is emitted in vmlinux BTF
1967 	 */
1968 	ref = (struct bpf_refcount *)(p__refcounted_kptr + meta->record->refcount_off);
1969 	if (!refcount_inc_not_zero((refcount_t *)ref))
1970 		return NULL;
1971 
1972 	/* Verifier strips KF_RET_NULL if input is owned ref, see is_kfunc_ret_null
1973 	 * in verifier.c
1974 	 */
1975 	return (void *)p__refcounted_kptr;
1976 }
1977 
1978 static int __bpf_list_add(struct bpf_list_node_kern *node,
1979 			  struct bpf_list_head *head,
1980 			  bool tail, struct btf_record *rec, u64 off)
1981 {
1982 	struct list_head *n = &node->list_head, *h = (void *)head;
1983 
1984 	/* If list_head was 0-initialized by map, bpf_obj_init_field wasn't
1985 	 * called on its fields, so init here
1986 	 */
1987 	if (unlikely(!h->next))
1988 		INIT_LIST_HEAD(h);
1989 
1990 	/* node->owner != NULL implies !list_empty(n), no need to separately
1991 	 * check the latter
1992 	 */
1993 	if (cmpxchg(&node->owner, NULL, BPF_PTR_POISON)) {
1994 		/* Only called from BPF prog, no need to migrate_disable */
1995 		__bpf_obj_drop_impl((void *)n - off, rec, false);
1996 		return -EINVAL;
1997 	}
1998 
1999 	tail ? list_add_tail(n, h) : list_add(n, h);
2000 	WRITE_ONCE(node->owner, head);
2001 
2002 	return 0;
2003 }
2004 
2005 __bpf_kfunc int bpf_list_push_front_impl(struct bpf_list_head *head,
2006 					 struct bpf_list_node *node,
2007 					 void *meta__ign, u64 off)
2008 {
2009 	struct bpf_list_node_kern *n = (void *)node;
2010 	struct btf_struct_meta *meta = meta__ign;
2011 
2012 	return __bpf_list_add(n, head, false, meta ? meta->record : NULL, off);
2013 }
2014 
2015 __bpf_kfunc int bpf_list_push_back_impl(struct bpf_list_head *head,
2016 					struct bpf_list_node *node,
2017 					void *meta__ign, u64 off)
2018 {
2019 	struct bpf_list_node_kern *n = (void *)node;
2020 	struct btf_struct_meta *meta = meta__ign;
2021 
2022 	return __bpf_list_add(n, head, true, meta ? meta->record : NULL, off);
2023 }
2024 
2025 static struct bpf_list_node *__bpf_list_del(struct bpf_list_head *head, bool tail)
2026 {
2027 	struct list_head *n, *h = (void *)head;
2028 	struct bpf_list_node_kern *node;
2029 
2030 	/* If list_head was 0-initialized by map, bpf_obj_init_field wasn't
2031 	 * called on its fields, so init here
2032 	 */
2033 	if (unlikely(!h->next))
2034 		INIT_LIST_HEAD(h);
2035 	if (list_empty(h))
2036 		return NULL;
2037 
2038 	n = tail ? h->prev : h->next;
2039 	node = container_of(n, struct bpf_list_node_kern, list_head);
2040 	if (WARN_ON_ONCE(READ_ONCE(node->owner) != head))
2041 		return NULL;
2042 
2043 	list_del_init(n);
2044 	WRITE_ONCE(node->owner, NULL);
2045 	return (struct bpf_list_node *)n;
2046 }
2047 
2048 __bpf_kfunc struct bpf_list_node *bpf_list_pop_front(struct bpf_list_head *head)
2049 {
2050 	return __bpf_list_del(head, false);
2051 }
2052 
2053 __bpf_kfunc struct bpf_list_node *bpf_list_pop_back(struct bpf_list_head *head)
2054 {
2055 	return __bpf_list_del(head, true);
2056 }
2057 
2058 __bpf_kfunc struct bpf_rb_node *bpf_rbtree_remove(struct bpf_rb_root *root,
2059 						  struct bpf_rb_node *node)
2060 {
2061 	struct bpf_rb_node_kern *node_internal = (struct bpf_rb_node_kern *)node;
2062 	struct rb_root_cached *r = (struct rb_root_cached *)root;
2063 	struct rb_node *n = &node_internal->rb_node;
2064 
2065 	/* node_internal->owner != root implies either RB_EMPTY_NODE(n) or
2066 	 * n is owned by some other tree. No need to check RB_EMPTY_NODE(n)
2067 	 */
2068 	if (READ_ONCE(node_internal->owner) != root)
2069 		return NULL;
2070 
2071 	rb_erase_cached(n, r);
2072 	RB_CLEAR_NODE(n);
2073 	WRITE_ONCE(node_internal->owner, NULL);
2074 	return (struct bpf_rb_node *)n;
2075 }
2076 
2077 /* Need to copy rbtree_add_cached's logic here because our 'less' is a BPF
2078  * program
2079  */
2080 static int __bpf_rbtree_add(struct bpf_rb_root *root,
2081 			    struct bpf_rb_node_kern *node,
2082 			    void *less, struct btf_record *rec, u64 off)
2083 {
2084 	struct rb_node **link = &((struct rb_root_cached *)root)->rb_root.rb_node;
2085 	struct rb_node *parent = NULL, *n = &node->rb_node;
2086 	bpf_callback_t cb = (bpf_callback_t)less;
2087 	bool leftmost = true;
2088 
2089 	/* node->owner != NULL implies !RB_EMPTY_NODE(n), no need to separately
2090 	 * check the latter
2091 	 */
2092 	if (cmpxchg(&node->owner, NULL, BPF_PTR_POISON)) {
2093 		/* Only called from BPF prog, no need to migrate_disable */
2094 		__bpf_obj_drop_impl((void *)n - off, rec, false);
2095 		return -EINVAL;
2096 	}
2097 
2098 	while (*link) {
2099 		parent = *link;
2100 		if (cb((uintptr_t)node, (uintptr_t)parent, 0, 0, 0)) {
2101 			link = &parent->rb_left;
2102 		} else {
2103 			link = &parent->rb_right;
2104 			leftmost = false;
2105 		}
2106 	}
2107 
2108 	rb_link_node(n, parent, link);
2109 	rb_insert_color_cached(n, (struct rb_root_cached *)root, leftmost);
2110 	WRITE_ONCE(node->owner, root);
2111 	return 0;
2112 }
2113 
2114 __bpf_kfunc int bpf_rbtree_add_impl(struct bpf_rb_root *root, struct bpf_rb_node *node,
2115 				    bool (less)(struct bpf_rb_node *a, const struct bpf_rb_node *b),
2116 				    void *meta__ign, u64 off)
2117 {
2118 	struct btf_struct_meta *meta = meta__ign;
2119 	struct bpf_rb_node_kern *n = (void *)node;
2120 
2121 	return __bpf_rbtree_add(root, n, (void *)less, meta ? meta->record : NULL, off);
2122 }
2123 
2124 __bpf_kfunc struct bpf_rb_node *bpf_rbtree_first(struct bpf_rb_root *root)
2125 {
2126 	struct rb_root_cached *r = (struct rb_root_cached *)root;
2127 
2128 	return (struct bpf_rb_node *)rb_first_cached(r);
2129 }
2130 
2131 /**
2132  * bpf_task_acquire - Acquire a reference to a task. A task acquired by this
2133  * kfunc which is not stored in a map as a kptr, must be released by calling
2134  * bpf_task_release().
2135  * @p: The task on which a reference is being acquired.
2136  */
2137 __bpf_kfunc struct task_struct *bpf_task_acquire(struct task_struct *p)
2138 {
2139 	if (refcount_inc_not_zero(&p->rcu_users))
2140 		return p;
2141 	return NULL;
2142 }
2143 
2144 /**
2145  * bpf_task_release - Release the reference acquired on a task.
2146  * @p: The task on which a reference is being released.
2147  */
2148 __bpf_kfunc void bpf_task_release(struct task_struct *p)
2149 {
2150 	put_task_struct_rcu_user(p);
2151 }
2152 
2153 #ifdef CONFIG_CGROUPS
2154 /**
2155  * bpf_cgroup_acquire - Acquire a reference to a cgroup. A cgroup acquired by
2156  * this kfunc which is not stored in a map as a kptr, must be released by
2157  * calling bpf_cgroup_release().
2158  * @cgrp: The cgroup on which a reference is being acquired.
2159  */
2160 __bpf_kfunc struct cgroup *bpf_cgroup_acquire(struct cgroup *cgrp)
2161 {
2162 	return cgroup_tryget(cgrp) ? cgrp : NULL;
2163 }
2164 
2165 /**
2166  * bpf_cgroup_release - Release the reference acquired on a cgroup.
2167  * If this kfunc is invoked in an RCU read region, the cgroup is guaranteed to
2168  * not be freed until the current grace period has ended, even if its refcount
2169  * drops to 0.
2170  * @cgrp: The cgroup on which a reference is being released.
2171  */
2172 __bpf_kfunc void bpf_cgroup_release(struct cgroup *cgrp)
2173 {
2174 	cgroup_put(cgrp);
2175 }
2176 
2177 /**
2178  * bpf_cgroup_ancestor - Perform a lookup on an entry in a cgroup's ancestor
2179  * array. A cgroup returned by this kfunc which is not subsequently stored in a
2180  * map, must be released by calling bpf_cgroup_release().
2181  * @cgrp: The cgroup for which we're performing a lookup.
2182  * @level: The level of ancestor to look up.
2183  */
2184 __bpf_kfunc struct cgroup *bpf_cgroup_ancestor(struct cgroup *cgrp, int level)
2185 {
2186 	struct cgroup *ancestor;
2187 
2188 	if (level > cgrp->level || level < 0)
2189 		return NULL;
2190 
2191 	/* cgrp's refcnt could be 0 here, but ancestors can still be accessed */
2192 	ancestor = cgrp->ancestors[level];
2193 	if (!cgroup_tryget(ancestor))
2194 		return NULL;
2195 	return ancestor;
2196 }
2197 
2198 /**
2199  * bpf_cgroup_from_id - Find a cgroup from its ID. A cgroup returned by this
2200  * kfunc which is not subsequently stored in a map, must be released by calling
2201  * bpf_cgroup_release().
2202  * @cgid: cgroup id.
2203  */
2204 __bpf_kfunc struct cgroup *bpf_cgroup_from_id(u64 cgid)
2205 {
2206 	struct cgroup *cgrp;
2207 
2208 	cgrp = cgroup_get_from_id(cgid);
2209 	if (IS_ERR(cgrp))
2210 		return NULL;
2211 	return cgrp;
2212 }
2213 
2214 /**
2215  * bpf_task_under_cgroup - wrap task_under_cgroup_hierarchy() as a kfunc, test
2216  * task's membership of cgroup ancestry.
2217  * @task: the task to be tested
2218  * @ancestor: possible ancestor of @task's cgroup
2219  *
2220  * Tests whether @task's default cgroup hierarchy is a descendant of @ancestor.
2221  * It follows all the same rules as cgroup_is_descendant, and only applies
2222  * to the default hierarchy.
2223  */
2224 __bpf_kfunc long bpf_task_under_cgroup(struct task_struct *task,
2225 				       struct cgroup *ancestor)
2226 {
2227 	long ret;
2228 
2229 	rcu_read_lock();
2230 	ret = task_under_cgroup_hierarchy(task, ancestor);
2231 	rcu_read_unlock();
2232 	return ret;
2233 }
2234 #endif /* CONFIG_CGROUPS */
2235 
2236 /**
2237  * bpf_task_from_pid - Find a struct task_struct from its pid by looking it up
2238  * in the root pid namespace idr. If a task is returned, it must either be
2239  * stored in a map, or released with bpf_task_release().
2240  * @pid: The pid of the task being looked up.
2241  */
2242 __bpf_kfunc struct task_struct *bpf_task_from_pid(s32 pid)
2243 {
2244 	struct task_struct *p;
2245 
2246 	rcu_read_lock();
2247 	p = find_task_by_pid_ns(pid, &init_pid_ns);
2248 	if (p)
2249 		p = bpf_task_acquire(p);
2250 	rcu_read_unlock();
2251 
2252 	return p;
2253 }
2254 
2255 /**
2256  * bpf_dynptr_slice() - Obtain a read-only pointer to the dynptr data.
2257  * @ptr: The dynptr whose data slice to retrieve
2258  * @offset: Offset into the dynptr
2259  * @buffer__opt: User-provided buffer to copy contents into.  May be NULL
2260  * @buffer__szk: Size (in bytes) of the buffer if present. This is the
2261  *               length of the requested slice. This must be a constant.
2262  *
2263  * For non-skb and non-xdp type dynptrs, there is no difference between
2264  * bpf_dynptr_slice and bpf_dynptr_data.
2265  *
2266  *  If buffer__opt is NULL, the call will fail if buffer_opt was needed.
2267  *
2268  * If the intention is to write to the data slice, please use
2269  * bpf_dynptr_slice_rdwr.
2270  *
2271  * The user must check that the returned pointer is not null before using it.
2272  *
2273  * Please note that in the case of skb and xdp dynptrs, bpf_dynptr_slice
2274  * does not change the underlying packet data pointers, so a call to
2275  * bpf_dynptr_slice will not invalidate any ctx->data/data_end pointers in
2276  * the bpf program.
2277  *
2278  * Return: NULL if the call failed (eg invalid dynptr), pointer to a read-only
2279  * data slice (can be either direct pointer to the data or a pointer to the user
2280  * provided buffer, with its contents containing the data, if unable to obtain
2281  * direct pointer)
2282  */
2283 __bpf_kfunc void *bpf_dynptr_slice(const struct bpf_dynptr_kern *ptr, u32 offset,
2284 				   void *buffer__opt, u32 buffer__szk)
2285 {
2286 	enum bpf_dynptr_type type;
2287 	u32 len = buffer__szk;
2288 	int err;
2289 
2290 	if (!ptr->data)
2291 		return NULL;
2292 
2293 	err = bpf_dynptr_check_off_len(ptr, offset, len);
2294 	if (err)
2295 		return NULL;
2296 
2297 	type = bpf_dynptr_get_type(ptr);
2298 
2299 	switch (type) {
2300 	case BPF_DYNPTR_TYPE_LOCAL:
2301 	case BPF_DYNPTR_TYPE_RINGBUF:
2302 		return ptr->data + ptr->offset + offset;
2303 	case BPF_DYNPTR_TYPE_SKB:
2304 		if (buffer__opt)
2305 			return skb_header_pointer(ptr->data, ptr->offset + offset, len, buffer__opt);
2306 		else
2307 			return skb_pointer_if_linear(ptr->data, ptr->offset + offset, len);
2308 	case BPF_DYNPTR_TYPE_XDP:
2309 	{
2310 		void *xdp_ptr = bpf_xdp_pointer(ptr->data, ptr->offset + offset, len);
2311 		if (!IS_ERR_OR_NULL(xdp_ptr))
2312 			return xdp_ptr;
2313 
2314 		if (!buffer__opt)
2315 			return NULL;
2316 		bpf_xdp_copy_buf(ptr->data, ptr->offset + offset, buffer__opt, len, false);
2317 		return buffer__opt;
2318 	}
2319 	default:
2320 		WARN_ONCE(true, "unknown dynptr type %d\n", type);
2321 		return NULL;
2322 	}
2323 }
2324 
2325 /**
2326  * bpf_dynptr_slice_rdwr() - Obtain a writable pointer to the dynptr data.
2327  * @ptr: The dynptr whose data slice to retrieve
2328  * @offset: Offset into the dynptr
2329  * @buffer__opt: User-provided buffer to copy contents into. May be NULL
2330  * @buffer__szk: Size (in bytes) of the buffer if present. This is the
2331  *               length of the requested slice. This must be a constant.
2332  *
2333  * For non-skb and non-xdp type dynptrs, there is no difference between
2334  * bpf_dynptr_slice and bpf_dynptr_data.
2335  *
2336  * If buffer__opt is NULL, the call will fail if buffer_opt was needed.
2337  *
2338  * The returned pointer is writable and may point to either directly the dynptr
2339  * data at the requested offset or to the buffer if unable to obtain a direct
2340  * data pointer to (example: the requested slice is to the paged area of an skb
2341  * packet). In the case where the returned pointer is to the buffer, the user
2342  * is responsible for persisting writes through calling bpf_dynptr_write(). This
2343  * usually looks something like this pattern:
2344  *
2345  * struct eth_hdr *eth = bpf_dynptr_slice_rdwr(&dynptr, 0, buffer, sizeof(buffer));
2346  * if (!eth)
2347  *	return TC_ACT_SHOT;
2348  *
2349  * // mutate eth header //
2350  *
2351  * if (eth == buffer)
2352  *	bpf_dynptr_write(&ptr, 0, buffer, sizeof(buffer), 0);
2353  *
2354  * Please note that, as in the example above, the user must check that the
2355  * returned pointer is not null before using it.
2356  *
2357  * Please also note that in the case of skb and xdp dynptrs, bpf_dynptr_slice_rdwr
2358  * does not change the underlying packet data pointers, so a call to
2359  * bpf_dynptr_slice_rdwr will not invalidate any ctx->data/data_end pointers in
2360  * the bpf program.
2361  *
2362  * Return: NULL if the call failed (eg invalid dynptr), pointer to a
2363  * data slice (can be either direct pointer to the data or a pointer to the user
2364  * provided buffer, with its contents containing the data, if unable to obtain
2365  * direct pointer)
2366  */
2367 __bpf_kfunc void *bpf_dynptr_slice_rdwr(const struct bpf_dynptr_kern *ptr, u32 offset,
2368 					void *buffer__opt, u32 buffer__szk)
2369 {
2370 	if (!ptr->data || __bpf_dynptr_is_rdonly(ptr))
2371 		return NULL;
2372 
2373 	/* bpf_dynptr_slice_rdwr is the same logic as bpf_dynptr_slice.
2374 	 *
2375 	 * For skb-type dynptrs, it is safe to write into the returned pointer
2376 	 * if the bpf program allows skb data writes. There are two possiblities
2377 	 * that may occur when calling bpf_dynptr_slice_rdwr:
2378 	 *
2379 	 * 1) The requested slice is in the head of the skb. In this case, the
2380 	 * returned pointer is directly to skb data, and if the skb is cloned, the
2381 	 * verifier will have uncloned it (see bpf_unclone_prologue()) already.
2382 	 * The pointer can be directly written into.
2383 	 *
2384 	 * 2) Some portion of the requested slice is in the paged buffer area.
2385 	 * In this case, the requested data will be copied out into the buffer
2386 	 * and the returned pointer will be a pointer to the buffer. The skb
2387 	 * will not be pulled. To persist the write, the user will need to call
2388 	 * bpf_dynptr_write(), which will pull the skb and commit the write.
2389 	 *
2390 	 * Similarly for xdp programs, if the requested slice is not across xdp
2391 	 * fragments, then a direct pointer will be returned, otherwise the data
2392 	 * will be copied out into the buffer and the user will need to call
2393 	 * bpf_dynptr_write() to commit changes.
2394 	 */
2395 	return bpf_dynptr_slice(ptr, offset, buffer__opt, buffer__szk);
2396 }
2397 
2398 __bpf_kfunc int bpf_dynptr_adjust(struct bpf_dynptr_kern *ptr, u32 start, u32 end)
2399 {
2400 	u32 size;
2401 
2402 	if (!ptr->data || start > end)
2403 		return -EINVAL;
2404 
2405 	size = __bpf_dynptr_size(ptr);
2406 
2407 	if (start > size || end > size)
2408 		return -ERANGE;
2409 
2410 	ptr->offset += start;
2411 	bpf_dynptr_set_size(ptr, end - start);
2412 
2413 	return 0;
2414 }
2415 
2416 __bpf_kfunc bool bpf_dynptr_is_null(struct bpf_dynptr_kern *ptr)
2417 {
2418 	return !ptr->data;
2419 }
2420 
2421 __bpf_kfunc bool bpf_dynptr_is_rdonly(struct bpf_dynptr_kern *ptr)
2422 {
2423 	if (!ptr->data)
2424 		return false;
2425 
2426 	return __bpf_dynptr_is_rdonly(ptr);
2427 }
2428 
2429 __bpf_kfunc __u32 bpf_dynptr_size(const struct bpf_dynptr_kern *ptr)
2430 {
2431 	if (!ptr->data)
2432 		return -EINVAL;
2433 
2434 	return __bpf_dynptr_size(ptr);
2435 }
2436 
2437 __bpf_kfunc int bpf_dynptr_clone(struct bpf_dynptr_kern *ptr,
2438 				 struct bpf_dynptr_kern *clone__uninit)
2439 {
2440 	if (!ptr->data) {
2441 		bpf_dynptr_set_null(clone__uninit);
2442 		return -EINVAL;
2443 	}
2444 
2445 	*clone__uninit = *ptr;
2446 
2447 	return 0;
2448 }
2449 
2450 __bpf_kfunc void *bpf_cast_to_kern_ctx(void *obj)
2451 {
2452 	return obj;
2453 }
2454 
2455 __bpf_kfunc void *bpf_rdonly_cast(void *obj__ign, u32 btf_id__k)
2456 {
2457 	return obj__ign;
2458 }
2459 
2460 __bpf_kfunc void bpf_rcu_read_lock(void)
2461 {
2462 	rcu_read_lock();
2463 }
2464 
2465 __bpf_kfunc void bpf_rcu_read_unlock(void)
2466 {
2467 	rcu_read_unlock();
2468 }
2469 
2470 struct bpf_throw_ctx {
2471 	struct bpf_prog_aux *aux;
2472 	u64 sp;
2473 	u64 bp;
2474 	int cnt;
2475 };
2476 
2477 static bool bpf_stack_walker(void *cookie, u64 ip, u64 sp, u64 bp)
2478 {
2479 	struct bpf_throw_ctx *ctx = cookie;
2480 	struct bpf_prog *prog;
2481 
2482 	if (!is_bpf_text_address(ip))
2483 		return !ctx->cnt;
2484 	prog = bpf_prog_ksym_find(ip);
2485 	ctx->cnt++;
2486 	if (bpf_is_subprog(prog))
2487 		return true;
2488 	ctx->aux = prog->aux;
2489 	ctx->sp = sp;
2490 	ctx->bp = bp;
2491 	return false;
2492 }
2493 
2494 __bpf_kfunc void bpf_throw(u64 cookie)
2495 {
2496 	struct bpf_throw_ctx ctx = {};
2497 
2498 	arch_bpf_stack_walk(bpf_stack_walker, &ctx);
2499 	WARN_ON_ONCE(!ctx.aux);
2500 	if (ctx.aux)
2501 		WARN_ON_ONCE(!ctx.aux->exception_boundary);
2502 	WARN_ON_ONCE(!ctx.bp);
2503 	WARN_ON_ONCE(!ctx.cnt);
2504 	/* Prevent KASAN false positives for CONFIG_KASAN_STACK by unpoisoning
2505 	 * deeper stack depths than ctx.sp as we do not return from bpf_throw,
2506 	 * which skips compiler generated instrumentation to do the same.
2507 	 */
2508 	kasan_unpoison_task_stack_below((void *)(long)ctx.sp);
2509 	ctx.aux->bpf_exception_cb(cookie, ctx.sp, ctx.bp);
2510 	WARN(1, "A call to BPF exception callback should never return\n");
2511 }
2512 
2513 __bpf_kfunc_end_defs();
2514 
2515 BTF_SET8_START(generic_btf_ids)
2516 #ifdef CONFIG_KEXEC_CORE
2517 BTF_ID_FLAGS(func, crash_kexec, KF_DESTRUCTIVE)
2518 #endif
2519 BTF_ID_FLAGS(func, bpf_obj_new_impl, KF_ACQUIRE | KF_RET_NULL)
2520 BTF_ID_FLAGS(func, bpf_percpu_obj_new_impl, KF_ACQUIRE | KF_RET_NULL)
2521 BTF_ID_FLAGS(func, bpf_obj_drop_impl, KF_RELEASE)
2522 BTF_ID_FLAGS(func, bpf_percpu_obj_drop_impl, KF_RELEASE)
2523 BTF_ID_FLAGS(func, bpf_refcount_acquire_impl, KF_ACQUIRE | KF_RET_NULL)
2524 BTF_ID_FLAGS(func, bpf_list_push_front_impl)
2525 BTF_ID_FLAGS(func, bpf_list_push_back_impl)
2526 BTF_ID_FLAGS(func, bpf_list_pop_front, KF_ACQUIRE | KF_RET_NULL)
2527 BTF_ID_FLAGS(func, bpf_list_pop_back, KF_ACQUIRE | KF_RET_NULL)
2528 BTF_ID_FLAGS(func, bpf_task_acquire, KF_ACQUIRE | KF_RCU | KF_RET_NULL)
2529 BTF_ID_FLAGS(func, bpf_task_release, KF_RELEASE)
2530 BTF_ID_FLAGS(func, bpf_rbtree_remove, KF_ACQUIRE | KF_RET_NULL)
2531 BTF_ID_FLAGS(func, bpf_rbtree_add_impl)
2532 BTF_ID_FLAGS(func, bpf_rbtree_first, KF_RET_NULL)
2533 
2534 #ifdef CONFIG_CGROUPS
2535 BTF_ID_FLAGS(func, bpf_cgroup_acquire, KF_ACQUIRE | KF_RCU | KF_RET_NULL)
2536 BTF_ID_FLAGS(func, bpf_cgroup_release, KF_RELEASE)
2537 BTF_ID_FLAGS(func, bpf_cgroup_ancestor, KF_ACQUIRE | KF_RCU | KF_RET_NULL)
2538 BTF_ID_FLAGS(func, bpf_cgroup_from_id, KF_ACQUIRE | KF_RET_NULL)
2539 BTF_ID_FLAGS(func, bpf_task_under_cgroup, KF_RCU)
2540 #endif
2541 BTF_ID_FLAGS(func, bpf_task_from_pid, KF_ACQUIRE | KF_RET_NULL)
2542 BTF_ID_FLAGS(func, bpf_throw)
2543 BTF_SET8_END(generic_btf_ids)
2544 
2545 static const struct btf_kfunc_id_set generic_kfunc_set = {
2546 	.owner = THIS_MODULE,
2547 	.set   = &generic_btf_ids,
2548 };
2549 
2550 
2551 BTF_ID_LIST(generic_dtor_ids)
2552 BTF_ID(struct, task_struct)
2553 BTF_ID(func, bpf_task_release)
2554 #ifdef CONFIG_CGROUPS
2555 BTF_ID(struct, cgroup)
2556 BTF_ID(func, bpf_cgroup_release)
2557 #endif
2558 
2559 BTF_SET8_START(common_btf_ids)
2560 BTF_ID_FLAGS(func, bpf_cast_to_kern_ctx)
2561 BTF_ID_FLAGS(func, bpf_rdonly_cast)
2562 BTF_ID_FLAGS(func, bpf_rcu_read_lock)
2563 BTF_ID_FLAGS(func, bpf_rcu_read_unlock)
2564 BTF_ID_FLAGS(func, bpf_dynptr_slice, KF_RET_NULL)
2565 BTF_ID_FLAGS(func, bpf_dynptr_slice_rdwr, KF_RET_NULL)
2566 BTF_ID_FLAGS(func, bpf_iter_num_new, KF_ITER_NEW)
2567 BTF_ID_FLAGS(func, bpf_iter_num_next, KF_ITER_NEXT | KF_RET_NULL)
2568 BTF_ID_FLAGS(func, bpf_iter_num_destroy, KF_ITER_DESTROY)
2569 BTF_ID_FLAGS(func, bpf_iter_task_vma_new, KF_ITER_NEW | KF_RCU)
2570 BTF_ID_FLAGS(func, bpf_iter_task_vma_next, KF_ITER_NEXT | KF_RET_NULL)
2571 BTF_ID_FLAGS(func, bpf_iter_task_vma_destroy, KF_ITER_DESTROY)
2572 #ifdef CONFIG_CGROUPS
2573 BTF_ID_FLAGS(func, bpf_iter_css_task_new, KF_ITER_NEW | KF_TRUSTED_ARGS)
2574 BTF_ID_FLAGS(func, bpf_iter_css_task_next, KF_ITER_NEXT | KF_RET_NULL)
2575 BTF_ID_FLAGS(func, bpf_iter_css_task_destroy, KF_ITER_DESTROY)
2576 BTF_ID_FLAGS(func, bpf_iter_css_new, KF_ITER_NEW | KF_TRUSTED_ARGS | KF_RCU_PROTECTED)
2577 BTF_ID_FLAGS(func, bpf_iter_css_next, KF_ITER_NEXT | KF_RET_NULL)
2578 BTF_ID_FLAGS(func, bpf_iter_css_destroy, KF_ITER_DESTROY)
2579 #endif
2580 BTF_ID_FLAGS(func, bpf_iter_task_new, KF_ITER_NEW | KF_TRUSTED_ARGS | KF_RCU_PROTECTED)
2581 BTF_ID_FLAGS(func, bpf_iter_task_next, KF_ITER_NEXT | KF_RET_NULL)
2582 BTF_ID_FLAGS(func, bpf_iter_task_destroy, KF_ITER_DESTROY)
2583 BTF_ID_FLAGS(func, bpf_dynptr_adjust)
2584 BTF_ID_FLAGS(func, bpf_dynptr_is_null)
2585 BTF_ID_FLAGS(func, bpf_dynptr_is_rdonly)
2586 BTF_ID_FLAGS(func, bpf_dynptr_size)
2587 BTF_ID_FLAGS(func, bpf_dynptr_clone)
2588 BTF_SET8_END(common_btf_ids)
2589 
2590 static const struct btf_kfunc_id_set common_kfunc_set = {
2591 	.owner = THIS_MODULE,
2592 	.set   = &common_btf_ids,
2593 };
2594 
2595 static int __init kfunc_init(void)
2596 {
2597 	int ret;
2598 	const struct btf_id_dtor_kfunc generic_dtors[] = {
2599 		{
2600 			.btf_id       = generic_dtor_ids[0],
2601 			.kfunc_btf_id = generic_dtor_ids[1]
2602 		},
2603 #ifdef CONFIG_CGROUPS
2604 		{
2605 			.btf_id       = generic_dtor_ids[2],
2606 			.kfunc_btf_id = generic_dtor_ids[3]
2607 		},
2608 #endif
2609 	};
2610 
2611 	ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, &generic_kfunc_set);
2612 	ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS, &generic_kfunc_set);
2613 	ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_STRUCT_OPS, &generic_kfunc_set);
2614 	ret = ret ?: register_btf_id_dtor_kfuncs(generic_dtors,
2615 						  ARRAY_SIZE(generic_dtors),
2616 						  THIS_MODULE);
2617 	return ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_UNSPEC, &common_kfunc_set);
2618 }
2619 
2620 late_initcall(kfunc_init);
2621