1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2017 - 2018 Covalent IO, Inc. http://covalent.io */
3
4 #include <linux/bpf.h>
5 #include <linux/btf_ids.h>
6 #include <linux/filter.h>
7 #include <linux/errno.h>
8 #include <linux/file.h>
9 #include <linux/net.h>
10 #include <linux/workqueue.h>
11 #include <linux/skmsg.h>
12 #include <linux/list.h>
13 #include <linux/jhash.h>
14 #include <linux/sock_diag.h>
15 #include <net/udp.h>
16
17 struct bpf_stab {
18 struct bpf_map map;
19 struct sock **sks;
20 struct sk_psock_progs progs;
21 spinlock_t lock;
22 };
23
24 #define SOCK_CREATE_FLAG_MASK \
25 (BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY)
26
27 /* This mutex is used to
28 * - protect race between prog/link attach/detach and link prog update, and
29 * - protect race between releasing and accessing map in bpf_link.
30 * A single global mutex lock is used since it is expected contention is low.
31 */
32 static DEFINE_MUTEX(sockmap_mutex);
33
34 static int sock_map_prog_update(struct bpf_map *map, struct bpf_prog *prog,
35 struct bpf_prog *old, struct bpf_link *link,
36 u32 which);
37 static struct sk_psock_progs *sock_map_progs(struct bpf_map *map);
38
39 static struct bpf_map *sock_map_alloc(union bpf_attr *attr)
40 {
41 struct bpf_stab *stab;
42
43 if (attr->max_entries == 0 ||
44 attr->key_size != 4 ||
45 (attr->value_size != sizeof(u32) &&
46 attr->value_size != sizeof(u64)) ||
47 attr->map_flags & ~SOCK_CREATE_FLAG_MASK)
48 return ERR_PTR(-EINVAL);
49
50 stab = bpf_map_area_alloc(sizeof(*stab), NUMA_NO_NODE);
51 if (!stab)
52 return ERR_PTR(-ENOMEM);
53
54 bpf_map_init_from_attr(&stab->map, attr);
55 spin_lock_init(&stab->lock);
56
57 stab->sks = bpf_map_area_alloc((u64) stab->map.max_entries *
58 sizeof(struct sock *),
59 stab->map.numa_node);
60 if (!stab->sks) {
61 bpf_map_area_free(stab);
62 return ERR_PTR(-ENOMEM);
63 }
64
65 return &stab->map;
66 }
67
68 int sock_map_get_from_fd(const union bpf_attr *attr, struct bpf_prog *prog)
69 {
70 u32 ufd = attr->target_fd;
71 struct bpf_map *map;
72 struct fd f;
73 int ret;
74
75 if (attr->attach_flags || attr->replace_bpf_fd)
76 return -EINVAL;
77
78 f = fdget(ufd);
79 map = __bpf_map_get(f);
80 if (IS_ERR(map))
81 return PTR_ERR(map);
82 mutex_lock(&sockmap_mutex);
83 ret = sock_map_prog_update(map, prog, NULL, NULL, attr->attach_type);
84 mutex_unlock(&sockmap_mutex);
85 fdput(f);
86 return ret;
87 }
88
89 int sock_map_prog_detach(const union bpf_attr *attr, enum bpf_prog_type ptype)
90 {
91 u32 ufd = attr->target_fd;
92 struct bpf_prog *prog;
93 struct bpf_map *map;
94 struct fd f;
95 int ret;
96
97 if (attr->attach_flags || attr->replace_bpf_fd)
98 return -EINVAL;
99
100 f = fdget(ufd);
101 map = __bpf_map_get(f);
102 if (IS_ERR(map))
103 return PTR_ERR(map);
104
105 prog = bpf_prog_get(attr->attach_bpf_fd);
106 if (IS_ERR(prog)) {
107 ret = PTR_ERR(prog);
108 goto put_map;
109 }
110
111 if (prog->type != ptype) {
112 ret = -EINVAL;
113 goto put_prog;
114 }
115
116 mutex_lock(&sockmap_mutex);
117 ret = sock_map_prog_update(map, NULL, prog, NULL, attr->attach_type);
118 mutex_unlock(&sockmap_mutex);
119 put_prog:
120 bpf_prog_put(prog);
121 put_map:
122 fdput(f);
123 return ret;
124 }
125
126 static void sock_map_sk_acquire(struct sock *sk)
127 __acquires(&sk->sk_lock.slock)
128 {
129 lock_sock(sk);
130 rcu_read_lock();
131 }
132
133 static void sock_map_sk_release(struct sock *sk)
134 __releases(&sk->sk_lock.slock)
135 {
136 rcu_read_unlock();
137 release_sock(sk);
138 }
139
140 static void sock_map_add_link(struct sk_psock *psock,
141 struct sk_psock_link *link,
142 struct bpf_map *map, void *link_raw)
143 {
144 link->link_raw = link_raw;
145 link->map = map;
146 spin_lock_bh(&psock->link_lock);
147 list_add_tail(&link->list, &psock->link);
148 spin_unlock_bh(&psock->link_lock);
149 }
150
151 static void sock_map_del_link(struct sock *sk,
152 struct sk_psock *psock, void *link_raw)
153 {
154 bool strp_stop = false, verdict_stop = false;
155 struct sk_psock_link *link, *tmp;
156
157 spin_lock_bh(&psock->link_lock);
158 list_for_each_entry_safe(link, tmp, &psock->link, list) {
159 if (link->link_raw == link_raw) {
160 struct bpf_map *map = link->map;
161 struct sk_psock_progs *progs = sock_map_progs(map);
162
163 if (psock->saved_data_ready && progs->stream_parser)
164 strp_stop = true;
165 if (psock->saved_data_ready && progs->stream_verdict)
166 verdict_stop = true;
167 if (psock->saved_data_ready && progs->skb_verdict)
168 verdict_stop = true;
169 list_del(&link->list);
170 sk_psock_free_link(link);
171 }
172 }
173 spin_unlock_bh(&psock->link_lock);
174 if (strp_stop || verdict_stop) {
175 write_lock_bh(&sk->sk_callback_lock);
176 if (strp_stop)
177 sk_psock_stop_strp(sk, psock);
178 if (verdict_stop)
179 sk_psock_stop_verdict(sk, psock);
180
181 if (psock->psock_update_sk_prot)
182 psock->psock_update_sk_prot(sk, psock, false);
183 write_unlock_bh(&sk->sk_callback_lock);
184 }
185 }
186
187 static void sock_map_unref(struct sock *sk, void *link_raw)
188 {
189 struct sk_psock *psock = sk_psock(sk);
190
191 if (likely(psock)) {
192 sock_map_del_link(sk, psock, link_raw);
193 sk_psock_put(sk, psock);
194 }
195 }
196
197 static int sock_map_init_proto(struct sock *sk, struct sk_psock *psock)
198 {
199 if (!sk->sk_prot->psock_update_sk_prot)
200 return -EINVAL;
201 psock->psock_update_sk_prot = sk->sk_prot->psock_update_sk_prot;
202 return sk->sk_prot->psock_update_sk_prot(sk, psock, false);
203 }
204
205 static struct sk_psock *sock_map_psock_get_checked(struct sock *sk)
206 {
207 struct sk_psock *psock;
208
209 rcu_read_lock();
210 psock = sk_psock(sk);
211 if (psock) {
212 if (sk->sk_prot->close != sock_map_close) {
213 psock = ERR_PTR(-EBUSY);
214 goto out;
215 }
216
217 if (!refcount_inc_not_zero(&psock->refcnt))
218 psock = ERR_PTR(-EBUSY);
219 }
220 out:
221 rcu_read_unlock();
222 return psock;
223 }
224
225 static int sock_map_link(struct bpf_map *map, struct sock *sk)
226 {
227 struct sk_psock_progs *progs = sock_map_progs(map);
228 struct bpf_prog *stream_verdict = NULL;
229 struct bpf_prog *stream_parser = NULL;
230 struct bpf_prog *skb_verdict = NULL;
231 struct bpf_prog *msg_parser = NULL;
232 struct sk_psock *psock;
233 int ret;
234
235 stream_verdict = READ_ONCE(progs->stream_verdict);
236 if (stream_verdict) {
237 stream_verdict = bpf_prog_inc_not_zero(stream_verdict);
238 if (IS_ERR(stream_verdict))
239 return PTR_ERR(stream_verdict);
240 }
241
242 stream_parser = READ_ONCE(progs->stream_parser);
243 if (stream_parser) {
244 stream_parser = bpf_prog_inc_not_zero(stream_parser);
245 if (IS_ERR(stream_parser)) {
246 ret = PTR_ERR(stream_parser);
247 goto out_put_stream_verdict;
248 }
249 }
250
251 msg_parser = READ_ONCE(progs->msg_parser);
252 if (msg_parser) {
253 msg_parser = bpf_prog_inc_not_zero(msg_parser);
254 if (IS_ERR(msg_parser)) {
255 ret = PTR_ERR(msg_parser);
256 goto out_put_stream_parser;
257 }
258 }
259
260 skb_verdict = READ_ONCE(progs->skb_verdict);
261 if (skb_verdict) {
262 skb_verdict = bpf_prog_inc_not_zero(skb_verdict);
263 if (IS_ERR(skb_verdict)) {
264 ret = PTR_ERR(skb_verdict);
265 goto out_put_msg_parser;
266 }
267 }
268
269 psock = sock_map_psock_get_checked(sk);
270 if (IS_ERR(psock)) {
271 ret = PTR_ERR(psock);
272 goto out_progs;
273 }
274
275 if (psock) {
276 if ((msg_parser && READ_ONCE(psock->progs.msg_parser)) ||
277 (stream_parser && READ_ONCE(psock->progs.stream_parser)) ||
278 (skb_verdict && READ_ONCE(psock->progs.skb_verdict)) ||
279 (skb_verdict && READ_ONCE(psock->progs.stream_verdict)) ||
280 (stream_verdict && READ_ONCE(psock->progs.skb_verdict)) ||
281 (stream_verdict && READ_ONCE(psock->progs.stream_verdict))) {
282 sk_psock_put(sk, psock);
283 ret = -EBUSY;
284 goto out_progs;
285 }
286 } else {
287 psock = sk_psock_init(sk, map->numa_node);
288 if (IS_ERR(psock)) {
289 ret = PTR_ERR(psock);
290 goto out_progs;
291 }
292 }
293
294 if (msg_parser)
295 psock_set_prog(&psock->progs.msg_parser, msg_parser);
296 if (stream_parser)
297 psock_set_prog(&psock->progs.stream_parser, stream_parser);
298 if (stream_verdict)
299 psock_set_prog(&psock->progs.stream_verdict, stream_verdict);
300 if (skb_verdict)
301 psock_set_prog(&psock->progs.skb_verdict, skb_verdict);
302
303 /* msg_* and stream_* programs references tracked in psock after this
304 * point. Reference dec and cleanup will occur through psock destructor
305 */
306 ret = sock_map_init_proto(sk, psock);
307 if (ret < 0) {
308 sk_psock_put(sk, psock);
309 goto out;
310 }
311
312 write_lock_bh(&sk->sk_callback_lock);
313 if (stream_parser && stream_verdict && !psock->saved_data_ready) {
314 ret = sk_psock_init_strp(sk, psock);
315 if (ret) {
316 write_unlock_bh(&sk->sk_callback_lock);
317 sk_psock_put(sk, psock);
318 goto out;
319 }
320 sk_psock_start_strp(sk, psock);
321 } else if (!stream_parser && stream_verdict && !psock->saved_data_ready) {
322 sk_psock_start_verdict(sk,psock);
323 } else if (!stream_verdict && skb_verdict && !psock->saved_data_ready) {
324 sk_psock_start_verdict(sk, psock);
325 }
326 write_unlock_bh(&sk->sk_callback_lock);
327 return 0;
328 out_progs:
329 if (skb_verdict)
330 bpf_prog_put(skb_verdict);
331 out_put_msg_parser:
332 if (msg_parser)
333 bpf_prog_put(msg_parser);
334 out_put_stream_parser:
335 if (stream_parser)
336 bpf_prog_put(stream_parser);
337 out_put_stream_verdict:
338 if (stream_verdict)
339 bpf_prog_put(stream_verdict);
340 out:
341 return ret;
342 }
343
344 static void sock_map_free(struct bpf_map *map)
345 {
346 struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
347 int i;
348
349 /* After the sync no updates or deletes will be in-flight so it
350 * is safe to walk map and remove entries without risking a race
351 * in EEXIST update case.
352 */
353 synchronize_rcu();
354 for (i = 0; i < stab->map.max_entries; i++) {
355 struct sock **psk = &stab->sks[i];
356 struct sock *sk;
357
358 sk = xchg(psk, NULL);
359 if (sk) {
360 sock_hold(sk);
361 lock_sock(sk);
362 rcu_read_lock();
363 sock_map_unref(sk, psk);
364 rcu_read_unlock();
365 release_sock(sk);
366 sock_put(sk);
367 }
368 }
369
370 /* wait for psock readers accessing its map link */
371 synchronize_rcu();
372
373 bpf_map_area_free(stab->sks);
374 bpf_map_area_free(stab);
375 }
376
377 static void sock_map_release_progs(struct bpf_map *map)
378 {
379 psock_progs_drop(&container_of(map, struct bpf_stab, map)->progs);
380 }
381
382 static struct sock *__sock_map_lookup_elem(struct bpf_map *map, u32 key)
383 {
384 struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
385
386 WARN_ON_ONCE(!rcu_read_lock_held());
387
388 if (unlikely(key >= map->max_entries))
389 return NULL;
390 return READ_ONCE(stab->sks[key]);
391 }
392
393 static void *sock_map_lookup(struct bpf_map *map, void *key)
394 {
395 struct sock *sk;
396
397 sk = __sock_map_lookup_elem(map, *(u32 *)key);
398 if (!sk)
399 return NULL;
400 if (sk_is_refcounted(sk) && !refcount_inc_not_zero(&sk->sk_refcnt))
401 return NULL;
402 return sk;
403 }
404
405 static void *sock_map_lookup_sys(struct bpf_map *map, void *key)
406 {
407 struct sock *sk;
408
409 if (map->value_size != sizeof(u64))
410 return ERR_PTR(-ENOSPC);
411
412 sk = __sock_map_lookup_elem(map, *(u32 *)key);
413 if (!sk)
414 return ERR_PTR(-ENOENT);
415
416 __sock_gen_cookie(sk);
417 return &sk->sk_cookie;
418 }
419
420 static int __sock_map_delete(struct bpf_stab *stab, struct sock *sk_test,
421 struct sock **psk)
422 {
423 struct sock *sk;
424 int err = 0;
425
426 spin_lock_bh(&stab->lock);
427 sk = *psk;
428 if (!sk_test || sk_test == sk)
429 sk = xchg(psk, NULL);
430
431 if (likely(sk))
432 sock_map_unref(sk, psk);
433 else
434 err = -EINVAL;
435
436 spin_unlock_bh(&stab->lock);
437 return err;
438 }
439
440 static void sock_map_delete_from_link(struct bpf_map *map, struct sock *sk,
441 void *link_raw)
442 {
443 struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
444
445 __sock_map_delete(stab, sk, link_raw);
446 }
447
448 static long sock_map_delete_elem(struct bpf_map *map, void *key)
449 {
450 struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
451 u32 i = *(u32 *)key;
452 struct sock **psk;
453
454 if (unlikely(i >= map->max_entries))
455 return -EINVAL;
456
457 psk = &stab->sks[i];
458 return __sock_map_delete(stab, NULL, psk);
459 }
460
461 static int sock_map_get_next_key(struct bpf_map *map, void *key, void *next)
462 {
463 struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
464 u32 i = key ? *(u32 *)key : U32_MAX;
465 u32 *key_next = next;
466
467 if (i == stab->map.max_entries - 1)
468 return -ENOENT;
469 if (i >= stab->map.max_entries)
470 *key_next = 0;
471 else
472 *key_next = i + 1;
473 return 0;
474 }
475
476 static int sock_map_update_common(struct bpf_map *map, u32 idx,
477 struct sock *sk, u64 flags)
478 {
479 struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
480 struct sk_psock_link *link;
481 struct sk_psock *psock;
482 struct sock *osk;
483 int ret;
484
485 WARN_ON_ONCE(!rcu_read_lock_held());
486 if (unlikely(flags > BPF_EXIST))
487 return -EINVAL;
488 if (unlikely(idx >= map->max_entries))
489 return -E2BIG;
490
491 link = sk_psock_init_link();
492 if (!link)
493 return -ENOMEM;
494
495 ret = sock_map_link(map, sk);
496 if (ret < 0)
497 goto out_free;
498
499 psock = sk_psock(sk);
500 WARN_ON_ONCE(!psock);
501
502 spin_lock_bh(&stab->lock);
503 osk = stab->sks[idx];
504 if (osk && flags == BPF_NOEXIST) {
505 ret = -EEXIST;
506 goto out_unlock;
507 } else if (!osk && flags == BPF_EXIST) {
508 ret = -ENOENT;
509 goto out_unlock;
510 }
511
512 sock_map_add_link(psock, link, map, &stab->sks[idx]);
513 stab->sks[idx] = sk;
514 if (osk)
515 sock_map_unref(osk, &stab->sks[idx]);
516 spin_unlock_bh(&stab->lock);
517 return 0;
518 out_unlock:
519 spin_unlock_bh(&stab->lock);
520 if (psock)
521 sk_psock_put(sk, psock);
522 out_free:
523 sk_psock_free_link(link);
524 return ret;
525 }
526
527 static bool sock_map_op_okay(const struct bpf_sock_ops_kern *ops)
528 {
529 return ops->op == BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB ||
530 ops->op == BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB ||
531 ops->op == BPF_SOCK_OPS_TCP_LISTEN_CB;
532 }
533
534 static bool sock_map_redirect_allowed(const struct sock *sk)
535 {
536 if (sk_is_tcp(sk))
537 return sk->sk_state != TCP_LISTEN;
538 else
539 return sk->sk_state == TCP_ESTABLISHED;
540 }
541
542 static bool sock_map_sk_is_suitable(const struct sock *sk)
543 {
544 return !!sk->sk_prot->psock_update_sk_prot;
545 }
546
547 static bool sock_map_sk_state_allowed(const struct sock *sk)
548 {
549 if (sk_is_tcp(sk))
550 return (1 << sk->sk_state) & (TCPF_ESTABLISHED | TCPF_LISTEN);
551 if (sk_is_stream_unix(sk))
552 return (1 << sk->sk_state) & TCPF_ESTABLISHED;
553 return true;
554 }
555
556 static int sock_hash_update_common(struct bpf_map *map, void *key,
557 struct sock *sk, u64 flags);
558
559 int sock_map_update_elem_sys(struct bpf_map *map, void *key, void *value,
560 u64 flags)
561 {
562 struct socket *sock;
563 struct sock *sk;
564 int ret;
565 u64 ufd;
566
567 if (map->value_size == sizeof(u64))
568 ufd = *(u64 *)value;
569 else
570 ufd = *(u32 *)value;
571 if (ufd > S32_MAX)
572 return -EINVAL;
573
574 sock = sockfd_lookup(ufd, &ret);
575 if (!sock)
576 return ret;
577 sk = sock->sk;
578 if (!sk) {
579 ret = -EINVAL;
580 goto out;
581 }
582 if (!sock_map_sk_is_suitable(sk)) {
583 ret = -EOPNOTSUPP;
584 goto out;
585 }
586
587 sock_map_sk_acquire(sk);
588 if (!sock_map_sk_state_allowed(sk))
589 ret = -EOPNOTSUPP;
590 else if (map->map_type == BPF_MAP_TYPE_SOCKMAP)
591 ret = sock_map_update_common(map, *(u32 *)key, sk, flags);
592 else
593 ret = sock_hash_update_common(map, key, sk, flags);
594 sock_map_sk_release(sk);
595 out:
596 sockfd_put(sock);
597 return ret;
598 }
599
600 static long sock_map_update_elem(struct bpf_map *map, void *key,
601 void *value, u64 flags)
602 {
603 struct sock *sk = (struct sock *)value;
604 int ret;
605
606 if (unlikely(!sk || !sk_fullsock(sk)))
607 return -EINVAL;
608
609 if (!sock_map_sk_is_suitable(sk))
610 return -EOPNOTSUPP;
611
612 local_bh_disable();
613 bh_lock_sock(sk);
614 if (!sock_map_sk_state_allowed(sk))
615 ret = -EOPNOTSUPP;
616 else if (map->map_type == BPF_MAP_TYPE_SOCKMAP)
617 ret = sock_map_update_common(map, *(u32 *)key, sk, flags);
618 else
619 ret = sock_hash_update_common(map, key, sk, flags);
620 bh_unlock_sock(sk);
621 local_bh_enable();
622 return ret;
623 }
624
625 BPF_CALL_4(bpf_sock_map_update, struct bpf_sock_ops_kern *, sops,
626 struct bpf_map *, map, void *, key, u64, flags)
627 {
628 WARN_ON_ONCE(!rcu_read_lock_held());
629
630 if (likely(sock_map_sk_is_suitable(sops->sk) &&
631 sock_map_op_okay(sops)))
632 return sock_map_update_common(map, *(u32 *)key, sops->sk,
633 flags);
634 return -EOPNOTSUPP;
635 }
636
637 const struct bpf_func_proto bpf_sock_map_update_proto = {
638 .func = bpf_sock_map_update,
639 .gpl_only = false,
640 .pkt_access = true,
641 .ret_type = RET_INTEGER,
642 .arg1_type = ARG_PTR_TO_CTX,
643 .arg2_type = ARG_CONST_MAP_PTR,
644 .arg3_type = ARG_PTR_TO_MAP_KEY,
645 .arg4_type = ARG_ANYTHING,
646 };
647
648 BPF_CALL_4(bpf_sk_redirect_map, struct sk_buff *, skb,
649 struct bpf_map *, map, u32, key, u64, flags)
650 {
651 struct sock *sk;
652
653 if (unlikely(flags & ~(BPF_F_INGRESS)))
654 return SK_DROP;
655
656 sk = __sock_map_lookup_elem(map, key);
657 if (unlikely(!sk || !sock_map_redirect_allowed(sk)))
658 return SK_DROP;
659
660 skb_bpf_set_redir(skb, sk, flags & BPF_F_INGRESS);
661 return SK_PASS;
662 }
663
664 const struct bpf_func_proto bpf_sk_redirect_map_proto = {
665 .func = bpf_sk_redirect_map,
666 .gpl_only = false,
667 .ret_type = RET_INTEGER,
668 .arg1_type = ARG_PTR_TO_CTX,
669 .arg2_type = ARG_CONST_MAP_PTR,
670 .arg3_type = ARG_ANYTHING,
671 .arg4_type = ARG_ANYTHING,
672 };
673
674 BPF_CALL_4(bpf_msg_redirect_map, struct sk_msg *, msg,
675 struct bpf_map *, map, u32, key, u64, flags)
676 {
677 struct sock *sk;
678
679 if (unlikely(flags & ~(BPF_F_INGRESS)))
680 return SK_DROP;
681
682 sk = __sock_map_lookup_elem(map, key);
683 if (unlikely(!sk || !sock_map_redirect_allowed(sk)))
684 return SK_DROP;
685 if (!(flags & BPF_F_INGRESS) && !sk_is_tcp(sk))
686 return SK_DROP;
687
688 msg->flags = flags;
689 msg->sk_redir = sk;
690 return SK_PASS;
691 }
692
693 const struct bpf_func_proto bpf_msg_redirect_map_proto = {
694 .func = bpf_msg_redirect_map,
695 .gpl_only = false,
696 .ret_type = RET_INTEGER,
697 .arg1_type = ARG_PTR_TO_CTX,
698 .arg2_type = ARG_CONST_MAP_PTR,
699 .arg3_type = ARG_ANYTHING,
700 .arg4_type = ARG_ANYTHING,
701 };
702
703 struct sock_map_seq_info {
704 struct bpf_map *map;
705 struct sock *sk;
706 u32 index;
707 };
708
709 struct bpf_iter__sockmap {
710 __bpf_md_ptr(struct bpf_iter_meta *, meta);
711 __bpf_md_ptr(struct bpf_map *, map);
712 __bpf_md_ptr(void *, key);
713 __bpf_md_ptr(struct sock *, sk);
714 };
715
716 DEFINE_BPF_ITER_FUNC(sockmap, struct bpf_iter_meta *meta,
717 struct bpf_map *map, void *key,
718 struct sock *sk)
719
720 static void *sock_map_seq_lookup_elem(struct sock_map_seq_info *info)
721 {
722 if (unlikely(info->index >= info->map->max_entries))
723 return NULL;
724
725 info->sk = __sock_map_lookup_elem(info->map, info->index);
726
727 /* can't return sk directly, since that might be NULL */
728 return info;
729 }
730
731 static void *sock_map_seq_start(struct seq_file *seq, loff_t *pos)
732 __acquires(rcu)
733 {
734 struct sock_map_seq_info *info = seq->private;
735
736 if (*pos == 0)
737 ++*pos;
738
739 /* pairs with sock_map_seq_stop */
740 rcu_read_lock();
741 return sock_map_seq_lookup_elem(info);
742 }
743
744 static void *sock_map_seq_next(struct seq_file *seq, void *v, loff_t *pos)
745 __must_hold(rcu)
746 {
747 struct sock_map_seq_info *info = seq->private;
748
749 ++*pos;
750 ++info->index;
751
752 return sock_map_seq_lookup_elem(info);
753 }
754
755 static int sock_map_seq_show(struct seq_file *seq, void *v)
756 __must_hold(rcu)
757 {
758 struct sock_map_seq_info *info = seq->private;
759 struct bpf_iter__sockmap ctx = {};
760 struct bpf_iter_meta meta;
761 struct bpf_prog *prog;
762
763 meta.seq = seq;
764 prog = bpf_iter_get_info(&meta, !v);
765 if (!prog)
766 return 0;
767
768 ctx.meta = &meta;
769 ctx.map = info->map;
770 if (v) {
771 ctx.key = &info->index;
772 ctx.sk = info->sk;
773 }
774
775 return bpf_iter_run_prog(prog, &ctx);
776 }
777
778 static void sock_map_seq_stop(struct seq_file *seq, void *v)
779 __releases(rcu)
780 {
781 if (!v)
782 (void)sock_map_seq_show(seq, NULL);
783
784 /* pairs with sock_map_seq_start */
785 rcu_read_unlock();
786 }
787
788 static const struct seq_operations sock_map_seq_ops = {
789 .start = sock_map_seq_start,
790 .next = sock_map_seq_next,
791 .stop = sock_map_seq_stop,
792 .show = sock_map_seq_show,
793 };
794
795 static int sock_map_init_seq_private(void *priv_data,
796 struct bpf_iter_aux_info *aux)
797 {
798 struct sock_map_seq_info *info = priv_data;
799
800 bpf_map_inc_with_uref(aux->map);
801 info->map = aux->map;
802 return 0;
803 }
804
805 static void sock_map_fini_seq_private(void *priv_data)
806 {
807 struct sock_map_seq_info *info = priv_data;
808
809 bpf_map_put_with_uref(info->map);
810 }
811
812 static u64 sock_map_mem_usage(const struct bpf_map *map)
813 {
814 u64 usage = sizeof(struct bpf_stab);
815
816 usage += (u64)map->max_entries * sizeof(struct sock *);
817 return usage;
818 }
819
820 static const struct bpf_iter_seq_info sock_map_iter_seq_info = {
821 .seq_ops = &sock_map_seq_ops,
822 .init_seq_private = sock_map_init_seq_private,
823 .fini_seq_private = sock_map_fini_seq_private,
824 .seq_priv_size = sizeof(struct sock_map_seq_info),
825 };
826
827 BTF_ID_LIST_SINGLE(sock_map_btf_ids, struct, bpf_stab)
828 const struct bpf_map_ops sock_map_ops = {
829 .map_meta_equal = bpf_map_meta_equal,
830 .map_alloc = sock_map_alloc,
831 .map_free = sock_map_free,
832 .map_get_next_key = sock_map_get_next_key,
833 .map_lookup_elem_sys_only = sock_map_lookup_sys,
834 .map_update_elem = sock_map_update_elem,
835 .map_delete_elem = sock_map_delete_elem,
836 .map_lookup_elem = sock_map_lookup,
837 .map_release_uref = sock_map_release_progs,
838 .map_check_btf = map_check_no_btf,
839 .map_mem_usage = sock_map_mem_usage,
840 .map_btf_id = &sock_map_btf_ids[0],
841 .iter_seq_info = &sock_map_iter_seq_info,
842 };
843
844 struct bpf_shtab_elem {
845 struct rcu_head rcu;
846 u32 hash;
847 struct sock *sk;
848 struct hlist_node node;
849 u8 key[];
850 };
851
852 struct bpf_shtab_bucket {
853 struct hlist_head head;
854 spinlock_t lock;
855 };
856
857 struct bpf_shtab {
858 struct bpf_map map;
859 struct bpf_shtab_bucket *buckets;
860 u32 buckets_num;
861 u32 elem_size;
862 struct sk_psock_progs progs;
863 atomic_t count;
864 };
865
866 static inline u32 sock_hash_bucket_hash(const void *key, u32 len)
867 {
868 return jhash(key, len, 0);
869 }
870
871 static struct bpf_shtab_bucket *sock_hash_select_bucket(struct bpf_shtab *htab,
872 u32 hash)
873 {
874 return &htab->buckets[hash & (htab->buckets_num - 1)];
875 }
876
877 static struct bpf_shtab_elem *
878 sock_hash_lookup_elem_raw(struct hlist_head *head, u32 hash, void *key,
879 u32 key_size)
880 {
881 struct bpf_shtab_elem *elem;
882
883 hlist_for_each_entry_rcu(elem, head, node) {
884 if (elem->hash == hash &&
885 !memcmp(&elem->key, key, key_size))
886 return elem;
887 }
888
889 return NULL;
890 }
891
892 static struct sock *__sock_hash_lookup_elem(struct bpf_map *map, void *key)
893 {
894 struct bpf_shtab *htab = container_of(map, struct bpf_shtab, map);
895 u32 key_size = map->key_size, hash;
896 struct bpf_shtab_bucket *bucket;
897 struct bpf_shtab_elem *elem;
898
899 WARN_ON_ONCE(!rcu_read_lock_held());
900
901 hash = sock_hash_bucket_hash(key, key_size);
902 bucket = sock_hash_select_bucket(htab, hash);
903 elem = sock_hash_lookup_elem_raw(&bucket->head, hash, key, key_size);
904
905 return elem ? elem->sk : NULL;
906 }
907
908 static void sock_hash_free_elem(struct bpf_shtab *htab,
909 struct bpf_shtab_elem *elem)
910 {
911 atomic_dec(&htab->count);
912 kfree_rcu(elem, rcu);
913 }
914
915 static void sock_hash_delete_from_link(struct bpf_map *map, struct sock *sk,
916 void *link_raw)
917 {
918 struct bpf_shtab *htab = container_of(map, struct bpf_shtab, map);
919 struct bpf_shtab_elem *elem_probe, *elem = link_raw;
920 struct bpf_shtab_bucket *bucket;
921
922 WARN_ON_ONCE(!rcu_read_lock_held());
923 bucket = sock_hash_select_bucket(htab, elem->hash);
924
925 /* elem may be deleted in parallel from the map, but access here
926 * is okay since it's going away only after RCU grace period.
927 * However, we need to check whether it's still present.
928 */
929 spin_lock_bh(&bucket->lock);
930 elem_probe = sock_hash_lookup_elem_raw(&bucket->head, elem->hash,
931 elem->key, map->key_size);
932 if (elem_probe && elem_probe == elem) {
933 hlist_del_rcu(&elem->node);
934 sock_map_unref(elem->sk, elem);
935 sock_hash_free_elem(htab, elem);
936 }
937 spin_unlock_bh(&bucket->lock);
938 }
939
940 static long sock_hash_delete_elem(struct bpf_map *map, void *key)
941 {
942 struct bpf_shtab *htab = container_of(map, struct bpf_shtab, map);
943 u32 hash, key_size = map->key_size;
944 struct bpf_shtab_bucket *bucket;
945 struct bpf_shtab_elem *elem;
946 int ret = -ENOENT;
947
948 hash = sock_hash_bucket_hash(key, key_size);
949 bucket = sock_hash_select_bucket(htab, hash);
950
951 spin_lock_bh(&bucket->lock);
952 elem = sock_hash_lookup_elem_raw(&bucket->head, hash, key, key_size);
953 if (elem) {
954 hlist_del_rcu(&elem->node);
955 sock_map_unref(elem->sk, elem);
956 sock_hash_free_elem(htab, elem);
957 ret = 0;
958 }
959 spin_unlock_bh(&bucket->lock);
960 return ret;
961 }
962
963 static struct bpf_shtab_elem *sock_hash_alloc_elem(struct bpf_shtab *htab,
964 void *key, u32 key_size,
965 u32 hash, struct sock *sk,
966 struct bpf_shtab_elem *old)
967 {
968 struct bpf_shtab_elem *new;
969
970 if (atomic_inc_return(&htab->count) > htab->map.max_entries) {
971 if (!old) {
972 atomic_dec(&htab->count);
973 return ERR_PTR(-E2BIG);
974 }
975 }
976
977 new = bpf_map_kmalloc_node(&htab->map, htab->elem_size,
978 GFP_ATOMIC | __GFP_NOWARN,
979 htab->map.numa_node);
980 if (!new) {
981 atomic_dec(&htab->count);
982 return ERR_PTR(-ENOMEM);
983 }
984 memcpy(new->key, key, key_size);
985 new->sk = sk;
986 new->hash = hash;
987 return new;
988 }
989
990 static int sock_hash_update_common(struct bpf_map *map, void *key,
991 struct sock *sk, u64 flags)
992 {
993 struct bpf_shtab *htab = container_of(map, struct bpf_shtab, map);
994 u32 key_size = map->key_size, hash;
995 struct bpf_shtab_elem *elem, *elem_new;
996 struct bpf_shtab_bucket *bucket;
997 struct sk_psock_link *link;
998 struct sk_psock *psock;
999 int ret;
1000
1001 WARN_ON_ONCE(!rcu_read_lock_held());
1002 if (unlikely(flags > BPF_EXIST))
1003 return -EINVAL;
1004
1005 link = sk_psock_init_link();
1006 if (!link)
1007 return -ENOMEM;
1008
1009 ret = sock_map_link(map, sk);
1010 if (ret < 0)
1011 goto out_free;
1012
1013 psock = sk_psock(sk);
1014 WARN_ON_ONCE(!psock);
1015
1016 hash = sock_hash_bucket_hash(key, key_size);
1017 bucket = sock_hash_select_bucket(htab, hash);
1018
1019 spin_lock_bh(&bucket->lock);
1020 elem = sock_hash_lookup_elem_raw(&bucket->head, hash, key, key_size);
1021 if (elem && flags == BPF_NOEXIST) {
1022 ret = -EEXIST;
1023 goto out_unlock;
1024 } else if (!elem && flags == BPF_EXIST) {
1025 ret = -ENOENT;
1026 goto out_unlock;
1027 }
1028
1029 elem_new = sock_hash_alloc_elem(htab, key, key_size, hash, sk, elem);
1030 if (IS_ERR(elem_new)) {
1031 ret = PTR_ERR(elem_new);
1032 goto out_unlock;
1033 }
1034
1035 sock_map_add_link(psock, link, map, elem_new);
1036 /* Add new element to the head of the list, so that
1037 * concurrent search will find it before old elem.
1038 */
1039 hlist_add_head_rcu(&elem_new->node, &bucket->head);
1040 if (elem) {
1041 hlist_del_rcu(&elem->node);
1042 sock_map_unref(elem->sk, elem);
1043 sock_hash_free_elem(htab, elem);
1044 }
1045 spin_unlock_bh(&bucket->lock);
1046 return 0;
1047 out_unlock:
1048 spin_unlock_bh(&bucket->lock);
1049 sk_psock_put(sk, psock);
1050 out_free:
1051 sk_psock_free_link(link);
1052 return ret;
1053 }
1054
1055 static int sock_hash_get_next_key(struct bpf_map *map, void *key,
1056 void *key_next)
1057 {
1058 struct bpf_shtab *htab = container_of(map, struct bpf_shtab, map);
1059 struct bpf_shtab_elem *elem, *elem_next;
1060 u32 hash, key_size = map->key_size;
1061 struct hlist_head *head;
1062 int i = 0;
1063
1064 if (!key)
1065 goto find_first_elem;
1066 hash = sock_hash_bucket_hash(key, key_size);
1067 head = &sock_hash_select_bucket(htab, hash)->head;
1068 elem = sock_hash_lookup_elem_raw(head, hash, key, key_size);
1069 if (!elem)
1070 goto find_first_elem;
1071
1072 elem_next = hlist_entry_safe(rcu_dereference(hlist_next_rcu(&elem->node)),
1073 struct bpf_shtab_elem, node);
1074 if (elem_next) {
1075 memcpy(key_next, elem_next->key, key_size);
1076 return 0;
1077 }
1078
1079 i = hash & (htab->buckets_num - 1);
1080 i++;
1081 find_first_elem:
1082 for (; i < htab->buckets_num; i++) {
1083 head = &sock_hash_select_bucket(htab, i)->head;
1084 elem_next = hlist_entry_safe(rcu_dereference(hlist_first_rcu(head)),
1085 struct bpf_shtab_elem, node);
1086 if (elem_next) {
1087 memcpy(key_next, elem_next->key, key_size);
1088 return 0;
1089 }
1090 }
1091
1092 return -ENOENT;
1093 }
1094
1095 static struct bpf_map *sock_hash_alloc(union bpf_attr *attr)
1096 {
1097 struct bpf_shtab *htab;
1098 int i, err;
1099
1100 if (attr->max_entries == 0 ||
1101 attr->key_size == 0 ||
1102 (attr->value_size != sizeof(u32) &&
1103 attr->value_size != sizeof(u64)) ||
1104 attr->map_flags & ~SOCK_CREATE_FLAG_MASK)
1105 return ERR_PTR(-EINVAL);
1106 if (attr->key_size > MAX_BPF_STACK)
1107 return ERR_PTR(-E2BIG);
1108
1109 htab = bpf_map_area_alloc(sizeof(*htab), NUMA_NO_NODE);
1110 if (!htab)
1111 return ERR_PTR(-ENOMEM);
1112
1113 bpf_map_init_from_attr(&htab->map, attr);
1114
1115 htab->buckets_num = roundup_pow_of_two(htab->map.max_entries);
1116 htab->elem_size = sizeof(struct bpf_shtab_elem) +
1117 round_up(htab->map.key_size, 8);
1118 if (htab->buckets_num == 0 ||
1119 htab->buckets_num > U32_MAX / sizeof(struct bpf_shtab_bucket)) {
1120 err = -EINVAL;
1121 goto free_htab;
1122 }
1123
1124 htab->buckets = bpf_map_area_alloc(htab->buckets_num *
1125 sizeof(struct bpf_shtab_bucket),
1126 htab->map.numa_node);
1127 if (!htab->buckets) {
1128 err = -ENOMEM;
1129 goto free_htab;
1130 }
1131
1132 for (i = 0; i < htab->buckets_num; i++) {
1133 INIT_HLIST_HEAD(&htab->buckets[i].head);
1134 spin_lock_init(&htab->buckets[i].lock);
1135 }
1136
1137 return &htab->map;
1138 free_htab:
1139 bpf_map_area_free(htab);
1140 return ERR_PTR(err);
1141 }
1142
1143 static void sock_hash_free(struct bpf_map *map)
1144 {
1145 struct bpf_shtab *htab = container_of(map, struct bpf_shtab, map);
1146 struct bpf_shtab_bucket *bucket;
1147 struct hlist_head unlink_list;
1148 struct bpf_shtab_elem *elem;
1149 struct hlist_node *node;
1150 int i;
1151
1152 /* After the sync no updates or deletes will be in-flight so it
1153 * is safe to walk map and remove entries without risking a race
1154 * in EEXIST update case.
1155 */
1156 synchronize_rcu();
1157 for (i = 0; i < htab->buckets_num; i++) {
1158 bucket = sock_hash_select_bucket(htab, i);
1159
1160 /* We are racing with sock_hash_delete_from_link to
1161 * enter the spin-lock critical section. Every socket on
1162 * the list is still linked to sockhash. Since link
1163 * exists, psock exists and holds a ref to socket. That
1164 * lets us to grab a socket ref too.
1165 */
1166 spin_lock_bh(&bucket->lock);
1167 hlist_for_each_entry(elem, &bucket->head, node)
1168 sock_hold(elem->sk);
1169 hlist_move_list(&bucket->head, &unlink_list);
1170 spin_unlock_bh(&bucket->lock);
1171
1172 /* Process removed entries out of atomic context to
1173 * block for socket lock before deleting the psock's
1174 * link to sockhash.
1175 */
1176 hlist_for_each_entry_safe(elem, node, &unlink_list, node) {
1177 hlist_del(&elem->node);
1178 lock_sock(elem->sk);
1179 rcu_read_lock();
1180 sock_map_unref(elem->sk, elem);
1181 rcu_read_unlock();
1182 release_sock(elem->sk);
1183 sock_put(elem->sk);
1184 sock_hash_free_elem(htab, elem);
1185 }
1186 cond_resched();
1187 }
1188
1189 /* wait for psock readers accessing its map link */
1190 synchronize_rcu();
1191
1192 bpf_map_area_free(htab->buckets);
1193 bpf_map_area_free(htab);
1194 }
1195
1196 static void *sock_hash_lookup_sys(struct bpf_map *map, void *key)
1197 {
1198 struct sock *sk;
1199
1200 if (map->value_size != sizeof(u64))
1201 return ERR_PTR(-ENOSPC);
1202
1203 sk = __sock_hash_lookup_elem(map, key);
1204 if (!sk)
1205 return ERR_PTR(-ENOENT);
1206
1207 __sock_gen_cookie(sk);
1208 return &sk->sk_cookie;
1209 }
1210
1211 static void *sock_hash_lookup(struct bpf_map *map, void *key)
1212 {
1213 struct sock *sk;
1214
1215 sk = __sock_hash_lookup_elem(map, key);
1216 if (!sk)
1217 return NULL;
1218 if (sk_is_refcounted(sk) && !refcount_inc_not_zero(&sk->sk_refcnt))
1219 return NULL;
1220 return sk;
1221 }
1222
1223 static void sock_hash_release_progs(struct bpf_map *map)
1224 {
1225 psock_progs_drop(&container_of(map, struct bpf_shtab, map)->progs);
1226 }
1227
1228 BPF_CALL_4(bpf_sock_hash_update, struct bpf_sock_ops_kern *, sops,
1229 struct bpf_map *, map, void *, key, u64, flags)
1230 {
1231 WARN_ON_ONCE(!rcu_read_lock_held());
1232
1233 if (likely(sock_map_sk_is_suitable(sops->sk) &&
1234 sock_map_op_okay(sops)))
1235 return sock_hash_update_common(map, key, sops->sk, flags);
1236 return -EOPNOTSUPP;
1237 }
1238
1239 const struct bpf_func_proto bpf_sock_hash_update_proto = {
1240 .func = bpf_sock_hash_update,
1241 .gpl_only = false,
1242 .pkt_access = true,
1243 .ret_type = RET_INTEGER,
1244 .arg1_type = ARG_PTR_TO_CTX,
1245 .arg2_type = ARG_CONST_MAP_PTR,
1246 .arg3_type = ARG_PTR_TO_MAP_KEY,
1247 .arg4_type = ARG_ANYTHING,
1248 };
1249
1250 BPF_CALL_4(bpf_sk_redirect_hash, struct sk_buff *, skb,
1251 struct bpf_map *, map, void *, key, u64, flags)
1252 {
1253 struct sock *sk;
1254
1255 if (unlikely(flags & ~(BPF_F_INGRESS)))
1256 return SK_DROP;
1257
1258 sk = __sock_hash_lookup_elem(map, key);
1259 if (unlikely(!sk || !sock_map_redirect_allowed(sk)))
1260 return SK_DROP;
1261
1262 skb_bpf_set_redir(skb, sk, flags & BPF_F_INGRESS);
1263 return SK_PASS;
1264 }
1265
1266 const struct bpf_func_proto bpf_sk_redirect_hash_proto = {
1267 .func = bpf_sk_redirect_hash,
1268 .gpl_only = false,
1269 .ret_type = RET_INTEGER,
1270 .arg1_type = ARG_PTR_TO_CTX,
1271 .arg2_type = ARG_CONST_MAP_PTR,
1272 .arg3_type = ARG_PTR_TO_MAP_KEY,
1273 .arg4_type = ARG_ANYTHING,
1274 };
1275
1276 BPF_CALL_4(bpf_msg_redirect_hash, struct sk_msg *, msg,
1277 struct bpf_map *, map, void *, key, u64, flags)
1278 {
1279 struct sock *sk;
1280
1281 if (unlikely(flags & ~(BPF_F_INGRESS)))
1282 return SK_DROP;
1283
1284 sk = __sock_hash_lookup_elem(map, key);
1285 if (unlikely(!sk || !sock_map_redirect_allowed(sk)))
1286 return SK_DROP;
1287 if (!(flags & BPF_F_INGRESS) && !sk_is_tcp(sk))
1288 return SK_DROP;
1289
1290 msg->flags = flags;
1291 msg->sk_redir = sk;
1292 return SK_PASS;
1293 }
1294
1295 const struct bpf_func_proto bpf_msg_redirect_hash_proto = {
1296 .func = bpf_msg_redirect_hash,
1297 .gpl_only = false,
1298 .ret_type = RET_INTEGER,
1299 .arg1_type = ARG_PTR_TO_CTX,
1300 .arg2_type = ARG_CONST_MAP_PTR,
1301 .arg3_type = ARG_PTR_TO_MAP_KEY,
1302 .arg4_type = ARG_ANYTHING,
1303 };
1304
1305 struct sock_hash_seq_info {
1306 struct bpf_map *map;
1307 struct bpf_shtab *htab;
1308 u32 bucket_id;
1309 };
1310
1311 static void *sock_hash_seq_find_next(struct sock_hash_seq_info *info,
1312 struct bpf_shtab_elem *prev_elem)
1313 {
1314 const struct bpf_shtab *htab = info->htab;
1315 struct bpf_shtab_bucket *bucket;
1316 struct bpf_shtab_elem *elem;
1317 struct hlist_node *node;
1318
1319 /* try to find next elem in the same bucket */
1320 if (prev_elem) {
1321 node = rcu_dereference(hlist_next_rcu(&prev_elem->node));
1322 elem = hlist_entry_safe(node, struct bpf_shtab_elem, node);
1323 if (elem)
1324 return elem;
1325
1326 /* no more elements, continue in the next bucket */
1327 info->bucket_id++;
1328 }
1329
1330 for (; info->bucket_id < htab->buckets_num; info->bucket_id++) {
1331 bucket = &htab->buckets[info->bucket_id];
1332 node = rcu_dereference(hlist_first_rcu(&bucket->head));
1333 elem = hlist_entry_safe(node, struct bpf_shtab_elem, node);
1334 if (elem)
1335 return elem;
1336 }
1337
1338 return NULL;
1339 }
1340
1341 static void *sock_hash_seq_start(struct seq_file *seq, loff_t *pos)
1342 __acquires(rcu)
1343 {
1344 struct sock_hash_seq_info *info = seq->private;
1345
1346 if (*pos == 0)
1347 ++*pos;
1348
1349 /* pairs with sock_hash_seq_stop */
1350 rcu_read_lock();
1351 return sock_hash_seq_find_next(info, NULL);
1352 }
1353
1354 static void *sock_hash_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1355 __must_hold(rcu)
1356 {
1357 struct sock_hash_seq_info *info = seq->private;
1358
1359 ++*pos;
1360 return sock_hash_seq_find_next(info, v);
1361 }
1362
1363 static int sock_hash_seq_show(struct seq_file *seq, void *v)
1364 __must_hold(rcu)
1365 {
1366 struct sock_hash_seq_info *info = seq->private;
1367 struct bpf_iter__sockmap ctx = {};
1368 struct bpf_shtab_elem *elem = v;
1369 struct bpf_iter_meta meta;
1370 struct bpf_prog *prog;
1371
1372 meta.seq = seq;
1373 prog = bpf_iter_get_info(&meta, !elem);
1374 if (!prog)
1375 return 0;
1376
1377 ctx.meta = &meta;
1378 ctx.map = info->map;
1379 if (elem) {
1380 ctx.key = elem->key;
1381 ctx.sk = elem->sk;
1382 }
1383
1384 return bpf_iter_run_prog(prog, &ctx);
1385 }
1386
1387 static void sock_hash_seq_stop(struct seq_file *seq, void *v)
1388 __releases(rcu)
1389 {
1390 if (!v)
1391 (void)sock_hash_seq_show(seq, NULL);
1392
1393 /* pairs with sock_hash_seq_start */
1394 rcu_read_unlock();
1395 }
1396
1397 static const struct seq_operations sock_hash_seq_ops = {
1398 .start = sock_hash_seq_start,
1399 .next = sock_hash_seq_next,
1400 .stop = sock_hash_seq_stop,
1401 .show = sock_hash_seq_show,
1402 };
1403
1404 static int sock_hash_init_seq_private(void *priv_data,
1405 struct bpf_iter_aux_info *aux)
1406 {
1407 struct sock_hash_seq_info *info = priv_data;
1408
1409 bpf_map_inc_with_uref(aux->map);
1410 info->map = aux->map;
1411 info->htab = container_of(aux->map, struct bpf_shtab, map);
1412 return 0;
1413 }
1414
1415 static void sock_hash_fini_seq_private(void *priv_data)
1416 {
1417 struct sock_hash_seq_info *info = priv_data;
1418
1419 bpf_map_put_with_uref(info->map);
1420 }
1421
1422 static u64 sock_hash_mem_usage(const struct bpf_map *map)
1423 {
1424 struct bpf_shtab *htab = container_of(map, struct bpf_shtab, map);
1425 u64 usage = sizeof(*htab);
1426
1427 usage += htab->buckets_num * sizeof(struct bpf_shtab_bucket);
1428 usage += atomic_read(&htab->count) * (u64)htab->elem_size;
1429 return usage;
1430 }
1431
1432 static const struct bpf_iter_seq_info sock_hash_iter_seq_info = {
1433 .seq_ops = &sock_hash_seq_ops,
1434 .init_seq_private = sock_hash_init_seq_private,
1435 .fini_seq_private = sock_hash_fini_seq_private,
1436 .seq_priv_size = sizeof(struct sock_hash_seq_info),
1437 };
1438
1439 BTF_ID_LIST_SINGLE(sock_hash_map_btf_ids, struct, bpf_shtab)
1440 const struct bpf_map_ops sock_hash_ops = {
1441 .map_meta_equal = bpf_map_meta_equal,
1442 .map_alloc = sock_hash_alloc,
1443 .map_free = sock_hash_free,
1444 .map_get_next_key = sock_hash_get_next_key,
1445 .map_update_elem = sock_map_update_elem,
1446 .map_delete_elem = sock_hash_delete_elem,
1447 .map_lookup_elem = sock_hash_lookup,
1448 .map_lookup_elem_sys_only = sock_hash_lookup_sys,
1449 .map_release_uref = sock_hash_release_progs,
1450 .map_check_btf = map_check_no_btf,
1451 .map_mem_usage = sock_hash_mem_usage,
1452 .map_btf_id = &sock_hash_map_btf_ids[0],
1453 .iter_seq_info = &sock_hash_iter_seq_info,
1454 };
1455
1456 static struct sk_psock_progs *sock_map_progs(struct bpf_map *map)
1457 {
1458 switch (map->map_type) {
1459 case BPF_MAP_TYPE_SOCKMAP:
1460 return &container_of(map, struct bpf_stab, map)->progs;
1461 case BPF_MAP_TYPE_SOCKHASH:
1462 return &container_of(map, struct bpf_shtab, map)->progs;
1463 default:
1464 break;
1465 }
1466
1467 return NULL;
1468 }
1469
1470 static int sock_map_prog_link_lookup(struct bpf_map *map, struct bpf_prog ***pprog,
1471 struct bpf_link ***plink, u32 which)
1472 {
1473 struct sk_psock_progs *progs = sock_map_progs(map);
1474 struct bpf_prog **cur_pprog;
1475 struct bpf_link **cur_plink;
1476
1477 if (!progs)
1478 return -EOPNOTSUPP;
1479
1480 switch (which) {
1481 case BPF_SK_MSG_VERDICT:
1482 cur_pprog = &progs->msg_parser;
1483 cur_plink = &progs->msg_parser_link;
1484 break;
1485 #if IS_ENABLED(CONFIG_BPF_STREAM_PARSER)
1486 case BPF_SK_SKB_STREAM_PARSER:
1487 cur_pprog = &progs->stream_parser;
1488 cur_plink = &progs->stream_parser_link;
1489 break;
1490 #endif
1491 case BPF_SK_SKB_STREAM_VERDICT:
1492 if (progs->skb_verdict)
1493 return -EBUSY;
1494 cur_pprog = &progs->stream_verdict;
1495 cur_plink = &progs->stream_verdict_link;
1496 break;
1497 case BPF_SK_SKB_VERDICT:
1498 if (progs->stream_verdict)
1499 return -EBUSY;
1500 cur_pprog = &progs->skb_verdict;
1501 cur_plink = &progs->skb_verdict_link;
1502 break;
1503 default:
1504 return -EOPNOTSUPP;
1505 }
1506
1507 *pprog = cur_pprog;
1508 if (plink)
1509 *plink = cur_plink;
1510 return 0;
1511 }
1512
1513 /* Handle the following four cases:
1514 * prog_attach: prog != NULL, old == NULL, link == NULL
1515 * prog_detach: prog == NULL, old != NULL, link == NULL
1516 * link_attach: prog != NULL, old == NULL, link != NULL
1517 * link_detach: prog == NULL, old != NULL, link != NULL
1518 */
1519 static int sock_map_prog_update(struct bpf_map *map, struct bpf_prog *prog,
1520 struct bpf_prog *old, struct bpf_link *link,
1521 u32 which)
1522 {
1523 struct bpf_prog **pprog;
1524 struct bpf_link **plink;
1525 int ret;
1526
1527 ret = sock_map_prog_link_lookup(map, &pprog, &plink, which);
1528 if (ret)
1529 return ret;
1530
1531 /* for prog_attach/prog_detach/link_attach, return error if a bpf_link
1532 * exists for that prog.
1533 */
1534 if ((!link || prog) && *plink)
1535 return -EBUSY;
1536
1537 if (old) {
1538 ret = psock_replace_prog(pprog, prog, old);
1539 if (!ret)
1540 *plink = NULL;
1541 } else {
1542 psock_set_prog(pprog, prog);
1543 if (link)
1544 *plink = link;
1545 }
1546
1547 return ret;
1548 }
1549
1550 int sock_map_bpf_prog_query(const union bpf_attr *attr,
1551 union bpf_attr __user *uattr)
1552 {
1553 __u32 __user *prog_ids = u64_to_user_ptr(attr->query.prog_ids);
1554 u32 prog_cnt = 0, flags = 0, ufd = attr->target_fd;
1555 struct bpf_prog **pprog;
1556 struct bpf_prog *prog;
1557 struct bpf_map *map;
1558 struct fd f;
1559 u32 id = 0;
1560 int ret;
1561
1562 if (attr->query.query_flags)
1563 return -EINVAL;
1564
1565 f = fdget(ufd);
1566 map = __bpf_map_get(f);
1567 if (IS_ERR(map))
1568 return PTR_ERR(map);
1569
1570 rcu_read_lock();
1571
1572 ret = sock_map_prog_link_lookup(map, &pprog, NULL, attr->query.attach_type);
1573 if (ret)
1574 goto end;
1575
1576 prog = *pprog;
1577 prog_cnt = !prog ? 0 : 1;
1578
1579 if (!attr->query.prog_cnt || !prog_ids || !prog_cnt)
1580 goto end;
1581
1582 /* we do not hold the refcnt, the bpf prog may be released
1583 * asynchronously and the id would be set to 0.
1584 */
1585 id = data_race(prog->aux->id);
1586 if (id == 0)
1587 prog_cnt = 0;
1588
1589 end:
1590 rcu_read_unlock();
1591
1592 if (copy_to_user(&uattr->query.attach_flags, &flags, sizeof(flags)) ||
1593 (id != 0 && copy_to_user(prog_ids, &id, sizeof(u32))) ||
1594 copy_to_user(&uattr->query.prog_cnt, &prog_cnt, sizeof(prog_cnt)))
1595 ret = -EFAULT;
1596
1597 fdput(f);
1598 return ret;
1599 }
1600
1601 static void sock_map_unlink(struct sock *sk, struct sk_psock_link *link)
1602 {
1603 switch (link->map->map_type) {
1604 case BPF_MAP_TYPE_SOCKMAP:
1605 return sock_map_delete_from_link(link->map, sk,
1606 link->link_raw);
1607 case BPF_MAP_TYPE_SOCKHASH:
1608 return sock_hash_delete_from_link(link->map, sk,
1609 link->link_raw);
1610 default:
1611 break;
1612 }
1613 }
1614
1615 static void sock_map_remove_links(struct sock *sk, struct sk_psock *psock)
1616 {
1617 struct sk_psock_link *link;
1618
1619 while ((link = sk_psock_link_pop(psock))) {
1620 sock_map_unlink(sk, link);
1621 sk_psock_free_link(link);
1622 }
1623 }
1624
1625 void sock_map_unhash(struct sock *sk)
1626 {
1627 void (*saved_unhash)(struct sock *sk);
1628 struct sk_psock *psock;
1629
1630 rcu_read_lock();
1631 psock = sk_psock(sk);
1632 if (unlikely(!psock)) {
1633 rcu_read_unlock();
1634 saved_unhash = READ_ONCE(sk->sk_prot)->unhash;
1635 } else {
1636 saved_unhash = psock->saved_unhash;
1637 sock_map_remove_links(sk, psock);
1638 rcu_read_unlock();
1639 }
1640 if (WARN_ON_ONCE(saved_unhash == sock_map_unhash))
1641 return;
1642 if (saved_unhash)
1643 saved_unhash(sk);
1644 }
1645 EXPORT_SYMBOL_GPL(sock_map_unhash);
1646
1647 void sock_map_destroy(struct sock *sk)
1648 {
1649 void (*saved_destroy)(struct sock *sk);
1650 struct sk_psock *psock;
1651
1652 rcu_read_lock();
1653 psock = sk_psock_get(sk);
1654 if (unlikely(!psock)) {
1655 rcu_read_unlock();
1656 saved_destroy = READ_ONCE(sk->sk_prot)->destroy;
1657 } else {
1658 saved_destroy = psock->saved_destroy;
1659 sock_map_remove_links(sk, psock);
1660 rcu_read_unlock();
1661 sk_psock_stop(psock);
1662 sk_psock_put(sk, psock);
1663 }
1664 if (WARN_ON_ONCE(saved_destroy == sock_map_destroy))
1665 return;
1666 if (saved_destroy)
1667 saved_destroy(sk);
1668 }
1669 EXPORT_SYMBOL_GPL(sock_map_destroy);
1670
1671 void sock_map_close(struct sock *sk, long timeout)
1672 {
1673 void (*saved_close)(struct sock *sk, long timeout);
1674 struct sk_psock *psock;
1675
1676 lock_sock(sk);
1677 rcu_read_lock();
1678 psock = sk_psock(sk);
1679 if (likely(psock)) {
1680 saved_close = psock->saved_close;
1681 sock_map_remove_links(sk, psock);
1682 psock = sk_psock_get(sk);
1683 if (unlikely(!psock))
1684 goto no_psock;
1685 rcu_read_unlock();
1686 sk_psock_stop(psock);
1687 release_sock(sk);
1688 cancel_delayed_work_sync(&psock->work);
1689 sk_psock_put(sk, psock);
1690 } else {
1691 saved_close = READ_ONCE(sk->sk_prot)->close;
1692 no_psock:
1693 rcu_read_unlock();
1694 release_sock(sk);
1695 }
1696
1697 /* Make sure we do not recurse. This is a bug.
1698 * Leak the socket instead of crashing on a stack overflow.
1699 */
1700 if (WARN_ON_ONCE(saved_close == sock_map_close))
1701 return;
1702 saved_close(sk, timeout);
1703 }
1704 EXPORT_SYMBOL_GPL(sock_map_close);
1705
1706 struct sockmap_link {
1707 struct bpf_link link;
1708 struct bpf_map *map;
1709 enum bpf_attach_type attach_type;
1710 };
1711
1712 static void sock_map_link_release(struct bpf_link *link)
1713 {
1714 struct sockmap_link *sockmap_link = container_of(link, struct sockmap_link, link);
1715
1716 mutex_lock(&sockmap_mutex);
1717 if (!sockmap_link->map)
1718 goto out;
1719
1720 WARN_ON_ONCE(sock_map_prog_update(sockmap_link->map, NULL, link->prog, link,
1721 sockmap_link->attach_type));
1722
1723 bpf_map_put_with_uref(sockmap_link->map);
1724 sockmap_link->map = NULL;
1725 out:
1726 mutex_unlock(&sockmap_mutex);
1727 }
1728
1729 static int sock_map_link_detach(struct bpf_link *link)
1730 {
1731 sock_map_link_release(link);
1732 return 0;
1733 }
1734
1735 static void sock_map_link_dealloc(struct bpf_link *link)
1736 {
1737 kfree(link);
1738 }
1739
1740 /* Handle the following two cases:
1741 * case 1: link != NULL, prog != NULL, old != NULL
1742 * case 2: link != NULL, prog != NULL, old == NULL
1743 */
1744 static int sock_map_link_update_prog(struct bpf_link *link,
1745 struct bpf_prog *prog,
1746 struct bpf_prog *old)
1747 {
1748 const struct sockmap_link *sockmap_link = container_of(link, struct sockmap_link, link);
1749 struct bpf_prog **pprog, *old_link_prog;
1750 struct bpf_link **plink;
1751 int ret = 0;
1752
1753 mutex_lock(&sockmap_mutex);
1754
1755 /* If old prog is not NULL, ensure old prog is the same as link->prog. */
1756 if (old && link->prog != old) {
1757 ret = -EPERM;
1758 goto out;
1759 }
1760 /* Ensure link->prog has the same type/attach_type as the new prog. */
1761 if (link->prog->type != prog->type ||
1762 link->prog->expected_attach_type != prog->expected_attach_type) {
1763 ret = -EINVAL;
1764 goto out;
1765 }
1766
1767 ret = sock_map_prog_link_lookup(sockmap_link->map, &pprog, &plink,
1768 sockmap_link->attach_type);
1769 if (ret)
1770 goto out;
1771
1772 /* return error if the stored bpf_link does not match the incoming bpf_link. */
1773 if (link != *plink) {
1774 ret = -EBUSY;
1775 goto out;
1776 }
1777
1778 if (old) {
1779 ret = psock_replace_prog(pprog, prog, old);
1780 if (ret)
1781 goto out;
1782 } else {
1783 psock_set_prog(pprog, prog);
1784 }
1785
1786 bpf_prog_inc(prog);
1787 old_link_prog = xchg(&link->prog, prog);
1788 bpf_prog_put(old_link_prog);
1789
1790 out:
1791 mutex_unlock(&sockmap_mutex);
1792 return ret;
1793 }
1794
1795 static u32 sock_map_link_get_map_id(const struct sockmap_link *sockmap_link)
1796 {
1797 u32 map_id = 0;
1798
1799 mutex_lock(&sockmap_mutex);
1800 if (sockmap_link->map)
1801 map_id = sockmap_link->map->id;
1802 mutex_unlock(&sockmap_mutex);
1803 return map_id;
1804 }
1805
1806 static int sock_map_link_fill_info(const struct bpf_link *link,
1807 struct bpf_link_info *info)
1808 {
1809 const struct sockmap_link *sockmap_link = container_of(link, struct sockmap_link, link);
1810 u32 map_id = sock_map_link_get_map_id(sockmap_link);
1811
1812 info->sockmap.map_id = map_id;
1813 info->sockmap.attach_type = sockmap_link->attach_type;
1814 return 0;
1815 }
1816
1817 static void sock_map_link_show_fdinfo(const struct bpf_link *link,
1818 struct seq_file *seq)
1819 {
1820 const struct sockmap_link *sockmap_link = container_of(link, struct sockmap_link, link);
1821 u32 map_id = sock_map_link_get_map_id(sockmap_link);
1822
1823 seq_printf(seq, "map_id:\t%u\n", map_id);
1824 seq_printf(seq, "attach_type:\t%u\n", sockmap_link->attach_type);
1825 }
1826
1827 static const struct bpf_link_ops sock_map_link_ops = {
1828 .release = sock_map_link_release,
1829 .dealloc = sock_map_link_dealloc,
1830 .detach = sock_map_link_detach,
1831 .update_prog = sock_map_link_update_prog,
1832 .fill_link_info = sock_map_link_fill_info,
1833 .show_fdinfo = sock_map_link_show_fdinfo,
1834 };
1835
1836 int sock_map_link_create(const union bpf_attr *attr, struct bpf_prog *prog)
1837 {
1838 struct bpf_link_primer link_primer;
1839 struct sockmap_link *sockmap_link;
1840 enum bpf_attach_type attach_type;
1841 struct bpf_map *map;
1842 int ret;
1843
1844 if (attr->link_create.flags)
1845 return -EINVAL;
1846
1847 map = bpf_map_get_with_uref(attr->link_create.target_fd);
1848 if (IS_ERR(map))
1849 return PTR_ERR(map);
1850 if (map->map_type != BPF_MAP_TYPE_SOCKMAP && map->map_type != BPF_MAP_TYPE_SOCKHASH) {
1851 ret = -EINVAL;
1852 goto out;
1853 }
1854
1855 sockmap_link = kzalloc(sizeof(*sockmap_link), GFP_USER);
1856 if (!sockmap_link) {
1857 ret = -ENOMEM;
1858 goto out;
1859 }
1860
1861 attach_type = attr->link_create.attach_type;
1862 bpf_link_init(&sockmap_link->link, BPF_LINK_TYPE_SOCKMAP, &sock_map_link_ops, prog);
1863 sockmap_link->map = map;
1864 sockmap_link->attach_type = attach_type;
1865
1866 ret = bpf_link_prime(&sockmap_link->link, &link_primer);
1867 if (ret) {
1868 kfree(sockmap_link);
1869 goto out;
1870 }
1871
1872 mutex_lock(&sockmap_mutex);
1873 ret = sock_map_prog_update(map, prog, NULL, &sockmap_link->link, attach_type);
1874 mutex_unlock(&sockmap_mutex);
1875 if (ret) {
1876 bpf_link_cleanup(&link_primer);
1877 goto out;
1878 }
1879
1880 /* Increase refcnt for the prog since when old prog is replaced with
1881 * psock_replace_prog() and psock_set_prog() its refcnt will be decreased.
1882 *
1883 * Actually, we do not need to increase refcnt for the prog since bpf_link
1884 * will hold a reference. But in order to have less complexity w.r.t.
1885 * replacing/setting prog, let us increase the refcnt to make things simpler.
1886 */
1887 bpf_prog_inc(prog);
1888
1889 return bpf_link_settle(&link_primer);
1890
1891 out:
1892 bpf_map_put_with_uref(map);
1893 return ret;
1894 }
1895
1896 static int sock_map_iter_attach_target(struct bpf_prog *prog,
1897 union bpf_iter_link_info *linfo,
1898 struct bpf_iter_aux_info *aux)
1899 {
1900 struct bpf_map *map;
1901 int err = -EINVAL;
1902
1903 if (!linfo->map.map_fd)
1904 return -EBADF;
1905
1906 map = bpf_map_get_with_uref(linfo->map.map_fd);
1907 if (IS_ERR(map))
1908 return PTR_ERR(map);
1909
1910 if (map->map_type != BPF_MAP_TYPE_SOCKMAP &&
1911 map->map_type != BPF_MAP_TYPE_SOCKHASH)
1912 goto put_map;
1913
1914 if (prog->aux->max_rdonly_access > map->key_size) {
1915 err = -EACCES;
1916 goto put_map;
1917 }
1918
1919 aux->map = map;
1920 return 0;
1921
1922 put_map:
1923 bpf_map_put_with_uref(map);
1924 return err;
1925 }
1926
1927 static void sock_map_iter_detach_target(struct bpf_iter_aux_info *aux)
1928 {
1929 bpf_map_put_with_uref(aux->map);
1930 }
1931
1932 static struct bpf_iter_reg sock_map_iter_reg = {
1933 .target = "sockmap",
1934 .attach_target = sock_map_iter_attach_target,
1935 .detach_target = sock_map_iter_detach_target,
1936 .show_fdinfo = bpf_iter_map_show_fdinfo,
1937 .fill_link_info = bpf_iter_map_fill_link_info,
1938 .ctx_arg_info_size = 2,
1939 .ctx_arg_info = {
1940 { offsetof(struct bpf_iter__sockmap, key),
1941 PTR_TO_BUF | PTR_MAYBE_NULL | MEM_RDONLY },
1942 { offsetof(struct bpf_iter__sockmap, sk),
1943 PTR_TO_BTF_ID_OR_NULL },
1944 },
1945 };
1946
1947 static int __init bpf_sockmap_iter_init(void)
1948 {
1949 sock_map_iter_reg.ctx_arg_info[1].btf_id =
1950 btf_sock_ids[BTF_SOCK_TYPE_SOCK];
1951 return bpf_iter_reg_target(&sock_map_iter_reg);
1952 }
1953 late_initcall(bpf_sockmap_iter_init);
1954
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.