1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (c) 2019 Facebook */
3#include <linux/rculist.h>
4#include <linux/list.h>
5#include <linux/hash.h>
6#include <linux/types.h>
7#include <linux/spinlock.h>
8#include <linux/bpf.h>
9#include <linux/btf.h>
10#include <linux/btf_ids.h>
11#include <linux/bpf_local_storage.h>
12#include <net/bpf_sk_storage.h>
13#include <net/sock.h>
14#include <uapi/linux/sock_diag.h>
15#include <uapi/linux/btf.h>
16#include <linux/rcupdate_trace.h>
17
18DEFINE_BPF_STORAGE_CACHE(sk_cache);
19
20static struct bpf_local_storage_data *
21bpf_sk_storage_lookup(struct sock *sk, struct bpf_map *map, bool cacheit_lockit)
22{
23 struct bpf_local_storage *sk_storage;
24 struct bpf_local_storage_map *smap;
25
26 sk_storage =
27 rcu_dereference_check(sk->sk_bpf_storage, bpf_rcu_lock_held());
28 if (!sk_storage)
29 return NULL;
30
31 smap = (struct bpf_local_storage_map *)map;
32 return bpf_local_storage_lookup(local_storage: sk_storage, smap, cacheit_lockit);
33}
34
35static int bpf_sk_storage_del(struct sock *sk, struct bpf_map *map)
36{
37 struct bpf_local_storage_data *sdata;
38
39 sdata = bpf_sk_storage_lookup(sk, map, cacheit_lockit: false);
40 if (!sdata)
41 return -ENOENT;
42
43 bpf_selem_unlink(SELEM(sdata), reuse_now: false);
44
45 return 0;
46}
47
48/* Called by __sk_destruct() & bpf_sk_storage_clone() */
49void bpf_sk_storage_free(struct sock *sk)
50{
51 struct bpf_local_storage *sk_storage;
52
53 rcu_read_lock();
54 sk_storage = rcu_dereference(sk->sk_bpf_storage);
55 if (!sk_storage) {
56 rcu_read_unlock();
57 return;
58 }
59
60 bpf_local_storage_destroy(local_storage: sk_storage);
61 rcu_read_unlock();
62}
63
64static void bpf_sk_storage_map_free(struct bpf_map *map)
65{
66 bpf_local_storage_map_free(map, cache: &sk_cache, NULL);
67}
68
69static struct bpf_map *bpf_sk_storage_map_alloc(union bpf_attr *attr)
70{
71 return bpf_local_storage_map_alloc(attr, cache: &sk_cache, bpf_ma: false);
72}
73
74static int notsupp_get_next_key(struct bpf_map *map, void *key,
75 void *next_key)
76{
77 return -ENOTSUPP;
78}
79
80static void *bpf_fd_sk_storage_lookup_elem(struct bpf_map *map, void *key)
81{
82 struct bpf_local_storage_data *sdata;
83 struct socket *sock;
84 int fd, err;
85
86 fd = *(int *)key;
87 sock = sockfd_lookup(fd, err: &err);
88 if (sock) {
89 sdata = bpf_sk_storage_lookup(sk: sock->sk, map, cacheit_lockit: true);
90 sockfd_put(sock);
91 return sdata ? sdata->data : NULL;
92 }
93
94 return ERR_PTR(error: err);
95}
96
97static long bpf_fd_sk_storage_update_elem(struct bpf_map *map, void *key,
98 void *value, u64 map_flags)
99{
100 struct bpf_local_storage_data *sdata;
101 struct socket *sock;
102 int fd, err;
103
104 fd = *(int *)key;
105 sock = sockfd_lookup(fd, err: &err);
106 if (sock) {
107 sdata = bpf_local_storage_update(
108 owner: sock->sk, smap: (struct bpf_local_storage_map *)map, value,
109 map_flags, GFP_ATOMIC);
110 sockfd_put(sock);
111 return PTR_ERR_OR_ZERO(ptr: sdata);
112 }
113
114 return err;
115}
116
117static long bpf_fd_sk_storage_delete_elem(struct bpf_map *map, void *key)
118{
119 struct socket *sock;
120 int fd, err;
121
122 fd = *(int *)key;
123 sock = sockfd_lookup(fd, err: &err);
124 if (sock) {
125 err = bpf_sk_storage_del(sk: sock->sk, map);
126 sockfd_put(sock);
127 return err;
128 }
129
130 return err;
131}
132
133static struct bpf_local_storage_elem *
134bpf_sk_storage_clone_elem(struct sock *newsk,
135 struct bpf_local_storage_map *smap,
136 struct bpf_local_storage_elem *selem)
137{
138 struct bpf_local_storage_elem *copy_selem;
139
140 copy_selem = bpf_selem_alloc(smap, owner: newsk, NULL, charge_mem: true, GFP_ATOMIC);
141 if (!copy_selem)
142 return NULL;
143
144 if (btf_record_has_field(rec: smap->map.record, type: BPF_SPIN_LOCK))
145 copy_map_value_locked(map: &smap->map, SDATA(copy_selem)->data,
146 SDATA(selem)->data, lock_src: true);
147 else
148 copy_map_value(map: &smap->map, SDATA(copy_selem)->data,
149 SDATA(selem)->data);
150
151 return copy_selem;
152}
153
154int bpf_sk_storage_clone(const struct sock *sk, struct sock *newsk)
155{
156 struct bpf_local_storage *new_sk_storage = NULL;
157 struct bpf_local_storage *sk_storage;
158 struct bpf_local_storage_elem *selem;
159 int ret = 0;
160
161 RCU_INIT_POINTER(newsk->sk_bpf_storage, NULL);
162
163 rcu_read_lock();
164 sk_storage = rcu_dereference(sk->sk_bpf_storage);
165
166 if (!sk_storage || hlist_empty(h: &sk_storage->list))
167 goto out;
168
169 hlist_for_each_entry_rcu(selem, &sk_storage->list, snode) {
170 struct bpf_local_storage_elem *copy_selem;
171 struct bpf_local_storage_map *smap;
172 struct bpf_map *map;
173
174 smap = rcu_dereference(SDATA(selem)->smap);
175 if (!(smap->map.map_flags & BPF_F_CLONE))
176 continue;
177
178 /* Note that for lockless listeners adding new element
179 * here can race with cleanup in bpf_local_storage_map_free.
180 * Try to grab map refcnt to make sure that it's still
181 * alive and prevent concurrent removal.
182 */
183 map = bpf_map_inc_not_zero(map: &smap->map);
184 if (IS_ERR(ptr: map))
185 continue;
186
187 copy_selem = bpf_sk_storage_clone_elem(newsk, smap, selem);
188 if (!copy_selem) {
189 ret = -ENOMEM;
190 bpf_map_put(map);
191 goto out;
192 }
193
194 if (new_sk_storage) {
195 bpf_selem_link_map(smap, selem: copy_selem);
196 bpf_selem_link_storage_nolock(local_storage: new_sk_storage, selem: copy_selem);
197 } else {
198 ret = bpf_local_storage_alloc(owner: newsk, smap, first_selem: copy_selem, GFP_ATOMIC);
199 if (ret) {
200 bpf_selem_free(selem: copy_selem, smap, reuse_now: true);
201 atomic_sub(i: smap->elem_size,
202 v: &newsk->sk_omem_alloc);
203 bpf_map_put(map);
204 goto out;
205 }
206
207 new_sk_storage =
208 rcu_dereference(copy_selem->local_storage);
209 }
210 bpf_map_put(map);
211 }
212
213out:
214 rcu_read_unlock();
215
216 /* In case of an error, don't free anything explicitly here, the
217 * caller is responsible to call bpf_sk_storage_free.
218 */
219
220 return ret;
221}
222
223/* *gfp_flags* is a hidden argument provided by the verifier */
224BPF_CALL_5(bpf_sk_storage_get, struct bpf_map *, map, struct sock *, sk,
225 void *, value, u64, flags, gfp_t, gfp_flags)
226{
227 struct bpf_local_storage_data *sdata;
228
229 WARN_ON_ONCE(!bpf_rcu_lock_held());
230 if (!sk || !sk_fullsock(sk) || flags > BPF_SK_STORAGE_GET_F_CREATE)
231 return (unsigned long)NULL;
232
233 sdata = bpf_sk_storage_lookup(sk, map, cacheit_lockit: true);
234 if (sdata)
235 return (unsigned long)sdata->data;
236
237 if (flags == BPF_SK_STORAGE_GET_F_CREATE &&
238 /* Cannot add new elem to a going away sk.
239 * Otherwise, the new elem may become a leak
240 * (and also other memory issues during map
241 * destruction).
242 */
243 refcount_inc_not_zero(r: &sk->sk_refcnt)) {
244 sdata = bpf_local_storage_update(
245 owner: sk, smap: (struct bpf_local_storage_map *)map, value,
246 map_flags: BPF_NOEXIST, gfp_flags);
247 /* sk must be a fullsock (guaranteed by verifier),
248 * so sock_gen_put() is unnecessary.
249 */
250 sock_put(sk);
251 return IS_ERR(ptr: sdata) ?
252 (unsigned long)NULL : (unsigned long)sdata->data;
253 }
254
255 return (unsigned long)NULL;
256}
257
258BPF_CALL_2(bpf_sk_storage_delete, struct bpf_map *, map, struct sock *, sk)
259{
260 WARN_ON_ONCE(!bpf_rcu_lock_held());
261 if (!sk || !sk_fullsock(sk))
262 return -EINVAL;
263
264 if (refcount_inc_not_zero(r: &sk->sk_refcnt)) {
265 int err;
266
267 err = bpf_sk_storage_del(sk, map);
268 sock_put(sk);
269 return err;
270 }
271
272 return -ENOENT;
273}
274
275static int bpf_sk_storage_charge(struct bpf_local_storage_map *smap,
276 void *owner, u32 size)
277{
278 struct sock *sk = (struct sock *)owner;
279 int optmem_max;
280
281 optmem_max = READ_ONCE(sock_net(sk)->core.sysctl_optmem_max);
282 /* same check as in sock_kmalloc() */
283 if (size <= optmem_max &&
284 atomic_read(v: &sk->sk_omem_alloc) + size < optmem_max) {
285 atomic_add(i: size, v: &sk->sk_omem_alloc);
286 return 0;
287 }
288
289 return -ENOMEM;
290}
291
292static void bpf_sk_storage_uncharge(struct bpf_local_storage_map *smap,
293 void *owner, u32 size)
294{
295 struct sock *sk = owner;
296
297 atomic_sub(i: size, v: &sk->sk_omem_alloc);
298}
299
300static struct bpf_local_storage __rcu **
301bpf_sk_storage_ptr(void *owner)
302{
303 struct sock *sk = owner;
304
305 return &sk->sk_bpf_storage;
306}
307
308const struct bpf_map_ops sk_storage_map_ops = {
309 .map_meta_equal = bpf_map_meta_equal,
310 .map_alloc_check = bpf_local_storage_map_alloc_check,
311 .map_alloc = bpf_sk_storage_map_alloc,
312 .map_free = bpf_sk_storage_map_free,
313 .map_get_next_key = notsupp_get_next_key,
314 .map_lookup_elem = bpf_fd_sk_storage_lookup_elem,
315 .map_update_elem = bpf_fd_sk_storage_update_elem,
316 .map_delete_elem = bpf_fd_sk_storage_delete_elem,
317 .map_check_btf = bpf_local_storage_map_check_btf,
318 .map_btf_id = &bpf_local_storage_map_btf_id[0],
319 .map_local_storage_charge = bpf_sk_storage_charge,
320 .map_local_storage_uncharge = bpf_sk_storage_uncharge,
321 .map_owner_storage_ptr = bpf_sk_storage_ptr,
322 .map_mem_usage = bpf_local_storage_map_mem_usage,
323};
324
325const struct bpf_func_proto bpf_sk_storage_get_proto = {
326 .func = bpf_sk_storage_get,
327 .gpl_only = false,
328 .ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL,
329 .arg1_type = ARG_CONST_MAP_PTR,
330 .arg2_type = ARG_PTR_TO_BTF_ID_SOCK_COMMON,
331 .arg3_type = ARG_PTR_TO_MAP_VALUE_OR_NULL,
332 .arg4_type = ARG_ANYTHING,
333};
334
335const struct bpf_func_proto bpf_sk_storage_get_cg_sock_proto = {
336 .func = bpf_sk_storage_get,
337 .gpl_only = false,
338 .ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL,
339 .arg1_type = ARG_CONST_MAP_PTR,
340 .arg2_type = ARG_PTR_TO_CTX, /* context is 'struct sock' */
341 .arg3_type = ARG_PTR_TO_MAP_VALUE_OR_NULL,
342 .arg4_type = ARG_ANYTHING,
343};
344
345const struct bpf_func_proto bpf_sk_storage_delete_proto = {
346 .func = bpf_sk_storage_delete,
347 .gpl_only = false,
348 .ret_type = RET_INTEGER,
349 .arg1_type = ARG_CONST_MAP_PTR,
350 .arg2_type = ARG_PTR_TO_BTF_ID_SOCK_COMMON,
351};
352
353static bool bpf_sk_storage_tracing_allowed(const struct bpf_prog *prog)
354{
355 const struct btf *btf_vmlinux;
356 const struct btf_type *t;
357 const char *tname;
358 u32 btf_id;
359
360 if (prog->aux->dst_prog)
361 return false;
362
363 /* Ensure the tracing program is not tracing
364 * any bpf_sk_storage*() function and also
365 * use the bpf_sk_storage_(get|delete) helper.
366 */
367 switch (prog->expected_attach_type) {
368 case BPF_TRACE_ITER:
369 case BPF_TRACE_RAW_TP:
370 /* bpf_sk_storage has no trace point */
371 return true;
372 case BPF_TRACE_FENTRY:
373 case BPF_TRACE_FEXIT:
374 btf_vmlinux = bpf_get_btf_vmlinux();
375 if (IS_ERR_OR_NULL(ptr: btf_vmlinux))
376 return false;
377 btf_id = prog->aux->attach_btf_id;
378 t = btf_type_by_id(btf: btf_vmlinux, type_id: btf_id);
379 tname = btf_name_by_offset(btf: btf_vmlinux, offset: t->name_off);
380 return !!strncmp(tname, "bpf_sk_storage",
381 strlen("bpf_sk_storage"));
382 default:
383 return false;
384 }
385
386 return false;
387}
388
389/* *gfp_flags* is a hidden argument provided by the verifier */
390BPF_CALL_5(bpf_sk_storage_get_tracing, struct bpf_map *, map, struct sock *, sk,
391 void *, value, u64, flags, gfp_t, gfp_flags)
392{
393 WARN_ON_ONCE(!bpf_rcu_lock_held());
394 if (in_hardirq() || in_nmi())
395 return (unsigned long)NULL;
396
397 return (unsigned long)____bpf_sk_storage_get(map, sk, value, flags,
398 gfp_flags);
399}
400
401BPF_CALL_2(bpf_sk_storage_delete_tracing, struct bpf_map *, map,
402 struct sock *, sk)
403{
404 WARN_ON_ONCE(!bpf_rcu_lock_held());
405 if (in_hardirq() || in_nmi())
406 return -EPERM;
407
408 return ____bpf_sk_storage_delete(map, sk);
409}
410
411const struct bpf_func_proto bpf_sk_storage_get_tracing_proto = {
412 .func = bpf_sk_storage_get_tracing,
413 .gpl_only = false,
414 .ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL,
415 .arg1_type = ARG_CONST_MAP_PTR,
416 .arg2_type = ARG_PTR_TO_BTF_ID_OR_NULL,
417 .arg2_btf_id = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON],
418 .arg3_type = ARG_PTR_TO_MAP_VALUE_OR_NULL,
419 .arg4_type = ARG_ANYTHING,
420 .allowed = bpf_sk_storage_tracing_allowed,
421};
422
423const struct bpf_func_proto bpf_sk_storage_delete_tracing_proto = {
424 .func = bpf_sk_storage_delete_tracing,
425 .gpl_only = false,
426 .ret_type = RET_INTEGER,
427 .arg1_type = ARG_CONST_MAP_PTR,
428 .arg2_type = ARG_PTR_TO_BTF_ID_OR_NULL,
429 .arg2_btf_id = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON],
430 .allowed = bpf_sk_storage_tracing_allowed,
431};
432
433struct bpf_sk_storage_diag {
434 u32 nr_maps;
435 struct bpf_map *maps[];
436};
437
438/* The reply will be like:
439 * INET_DIAG_BPF_SK_STORAGES (nla_nest)
440 * SK_DIAG_BPF_STORAGE (nla_nest)
441 * SK_DIAG_BPF_STORAGE_MAP_ID (nla_put_u32)
442 * SK_DIAG_BPF_STORAGE_MAP_VALUE (nla_reserve_64bit)
443 * SK_DIAG_BPF_STORAGE (nla_nest)
444 * SK_DIAG_BPF_STORAGE_MAP_ID (nla_put_u32)
445 * SK_DIAG_BPF_STORAGE_MAP_VALUE (nla_reserve_64bit)
446 * ....
447 */
448static int nla_value_size(u32 value_size)
449{
450 /* SK_DIAG_BPF_STORAGE (nla_nest)
451 * SK_DIAG_BPF_STORAGE_MAP_ID (nla_put_u32)
452 * SK_DIAG_BPF_STORAGE_MAP_VALUE (nla_reserve_64bit)
453 */
454 return nla_total_size(payload: 0) + nla_total_size(payload: sizeof(u32)) +
455 nla_total_size_64bit(payload: value_size);
456}
457
458void bpf_sk_storage_diag_free(struct bpf_sk_storage_diag *diag)
459{
460 u32 i;
461
462 if (!diag)
463 return;
464
465 for (i = 0; i < diag->nr_maps; i++)
466 bpf_map_put(map: diag->maps[i]);
467
468 kfree(objp: diag);
469}
470EXPORT_SYMBOL_GPL(bpf_sk_storage_diag_free);
471
472static bool diag_check_dup(const struct bpf_sk_storage_diag *diag,
473 const struct bpf_map *map)
474{
475 u32 i;
476
477 for (i = 0; i < diag->nr_maps; i++) {
478 if (diag->maps[i] == map)
479 return true;
480 }
481
482 return false;
483}
484
485struct bpf_sk_storage_diag *
486bpf_sk_storage_diag_alloc(const struct nlattr *nla_stgs)
487{
488 struct bpf_sk_storage_diag *diag;
489 struct nlattr *nla;
490 u32 nr_maps = 0;
491 int rem, err;
492
493 /* bpf_local_storage_map is currently limited to CAP_SYS_ADMIN as
494 * the map_alloc_check() side also does.
495 */
496 if (!bpf_capable())
497 return ERR_PTR(error: -EPERM);
498
499 nla_for_each_nested(nla, nla_stgs, rem) {
500 if (nla_type(nla) == SK_DIAG_BPF_STORAGE_REQ_MAP_FD) {
501 if (nla_len(nla) != sizeof(u32))
502 return ERR_PTR(error: -EINVAL);
503 nr_maps++;
504 }
505 }
506
507 diag = kzalloc(struct_size(diag, maps, nr_maps), GFP_KERNEL);
508 if (!diag)
509 return ERR_PTR(error: -ENOMEM);
510
511 nla_for_each_nested(nla, nla_stgs, rem) {
512 struct bpf_map *map;
513 int map_fd;
514
515 if (nla_type(nla) != SK_DIAG_BPF_STORAGE_REQ_MAP_FD)
516 continue;
517
518 map_fd = nla_get_u32(nla);
519 map = bpf_map_get(ufd: map_fd);
520 if (IS_ERR(ptr: map)) {
521 err = PTR_ERR(ptr: map);
522 goto err_free;
523 }
524 if (map->map_type != BPF_MAP_TYPE_SK_STORAGE) {
525 bpf_map_put(map);
526 err = -EINVAL;
527 goto err_free;
528 }
529 if (diag_check_dup(diag, map)) {
530 bpf_map_put(map);
531 err = -EEXIST;
532 goto err_free;
533 }
534 diag->maps[diag->nr_maps++] = map;
535 }
536
537 return diag;
538
539err_free:
540 bpf_sk_storage_diag_free(diag);
541 return ERR_PTR(error: err);
542}
543EXPORT_SYMBOL_GPL(bpf_sk_storage_diag_alloc);
544
545static int diag_get(struct bpf_local_storage_data *sdata, struct sk_buff *skb)
546{
547 struct nlattr *nla_stg, *nla_value;
548 struct bpf_local_storage_map *smap;
549
550 /* It cannot exceed max nlattr's payload */
551 BUILD_BUG_ON(U16_MAX - NLA_HDRLEN < BPF_LOCAL_STORAGE_MAX_VALUE_SIZE);
552
553 nla_stg = nla_nest_start(skb, attrtype: SK_DIAG_BPF_STORAGE);
554 if (!nla_stg)
555 return -EMSGSIZE;
556
557 smap = rcu_dereference(sdata->smap);
558 if (nla_put_u32(skb, attrtype: SK_DIAG_BPF_STORAGE_MAP_ID, value: smap->map.id))
559 goto errout;
560
561 nla_value = nla_reserve_64bit(skb, attrtype: SK_DIAG_BPF_STORAGE_MAP_VALUE,
562 attrlen: smap->map.value_size,
563 padattr: SK_DIAG_BPF_STORAGE_PAD);
564 if (!nla_value)
565 goto errout;
566
567 if (btf_record_has_field(rec: smap->map.record, type: BPF_SPIN_LOCK))
568 copy_map_value_locked(map: &smap->map, dst: nla_data(nla: nla_value),
569 src: sdata->data, lock_src: true);
570 else
571 copy_map_value(map: &smap->map, dst: nla_data(nla: nla_value), src: sdata->data);
572
573 nla_nest_end(skb, start: nla_stg);
574 return 0;
575
576errout:
577 nla_nest_cancel(skb, start: nla_stg);
578 return -EMSGSIZE;
579}
580
581static int bpf_sk_storage_diag_put_all(struct sock *sk, struct sk_buff *skb,
582 int stg_array_type,
583 unsigned int *res_diag_size)
584{
585 /* stg_array_type (e.g. INET_DIAG_BPF_SK_STORAGES) */
586 unsigned int diag_size = nla_total_size(payload: 0);
587 struct bpf_local_storage *sk_storage;
588 struct bpf_local_storage_elem *selem;
589 struct bpf_local_storage_map *smap;
590 struct nlattr *nla_stgs;
591 unsigned int saved_len;
592 int err = 0;
593
594 rcu_read_lock();
595
596 sk_storage = rcu_dereference(sk->sk_bpf_storage);
597 if (!sk_storage || hlist_empty(h: &sk_storage->list)) {
598 rcu_read_unlock();
599 return 0;
600 }
601
602 nla_stgs = nla_nest_start(skb, attrtype: stg_array_type);
603 if (!nla_stgs)
604 /* Continue to learn diag_size */
605 err = -EMSGSIZE;
606
607 saved_len = skb->len;
608 hlist_for_each_entry_rcu(selem, &sk_storage->list, snode) {
609 smap = rcu_dereference(SDATA(selem)->smap);
610 diag_size += nla_value_size(value_size: smap->map.value_size);
611
612 if (nla_stgs && diag_get(SDATA(selem), skb))
613 /* Continue to learn diag_size */
614 err = -EMSGSIZE;
615 }
616
617 rcu_read_unlock();
618
619 if (nla_stgs) {
620 if (saved_len == skb->len)
621 nla_nest_cancel(skb, start: nla_stgs);
622 else
623 nla_nest_end(skb, start: nla_stgs);
624 }
625
626 if (diag_size == nla_total_size(payload: 0)) {
627 *res_diag_size = 0;
628 return 0;
629 }
630
631 *res_diag_size = diag_size;
632 return err;
633}
634
635int bpf_sk_storage_diag_put(struct bpf_sk_storage_diag *diag,
636 struct sock *sk, struct sk_buff *skb,
637 int stg_array_type,
638 unsigned int *res_diag_size)
639{
640 /* stg_array_type (e.g. INET_DIAG_BPF_SK_STORAGES) */
641 unsigned int diag_size = nla_total_size(payload: 0);
642 struct bpf_local_storage *sk_storage;
643 struct bpf_local_storage_data *sdata;
644 struct nlattr *nla_stgs;
645 unsigned int saved_len;
646 int err = 0;
647 u32 i;
648
649 *res_diag_size = 0;
650
651 /* No map has been specified. Dump all. */
652 if (!diag->nr_maps)
653 return bpf_sk_storage_diag_put_all(sk, skb, stg_array_type,
654 res_diag_size);
655
656 rcu_read_lock();
657 sk_storage = rcu_dereference(sk->sk_bpf_storage);
658 if (!sk_storage || hlist_empty(h: &sk_storage->list)) {
659 rcu_read_unlock();
660 return 0;
661 }
662
663 nla_stgs = nla_nest_start(skb, attrtype: stg_array_type);
664 if (!nla_stgs)
665 /* Continue to learn diag_size */
666 err = -EMSGSIZE;
667
668 saved_len = skb->len;
669 for (i = 0; i < diag->nr_maps; i++) {
670 sdata = bpf_local_storage_lookup(local_storage: sk_storage,
671 smap: (struct bpf_local_storage_map *)diag->maps[i],
672 cacheit_lockit: false);
673
674 if (!sdata)
675 continue;
676
677 diag_size += nla_value_size(value_size: diag->maps[i]->value_size);
678
679 if (nla_stgs && diag_get(sdata, skb))
680 /* Continue to learn diag_size */
681 err = -EMSGSIZE;
682 }
683 rcu_read_unlock();
684
685 if (nla_stgs) {
686 if (saved_len == skb->len)
687 nla_nest_cancel(skb, start: nla_stgs);
688 else
689 nla_nest_end(skb, start: nla_stgs);
690 }
691
692 if (diag_size == nla_total_size(payload: 0)) {
693 *res_diag_size = 0;
694 return 0;
695 }
696
697 *res_diag_size = diag_size;
698 return err;
699}
700EXPORT_SYMBOL_GPL(bpf_sk_storage_diag_put);
701
702struct bpf_iter_seq_sk_storage_map_info {
703 struct bpf_map *map;
704 unsigned int bucket_id;
705 unsigned skip_elems;
706};
707
708static struct bpf_local_storage_elem *
709bpf_sk_storage_map_seq_find_next(struct bpf_iter_seq_sk_storage_map_info *info,
710 struct bpf_local_storage_elem *prev_selem)
711 __acquires(RCU) __releases(RCU)
712{
713 struct bpf_local_storage *sk_storage;
714 struct bpf_local_storage_elem *selem;
715 u32 skip_elems = info->skip_elems;
716 struct bpf_local_storage_map *smap;
717 u32 bucket_id = info->bucket_id;
718 u32 i, count, n_buckets;
719 struct bpf_local_storage_map_bucket *b;
720
721 smap = (struct bpf_local_storage_map *)info->map;
722 n_buckets = 1U << smap->bucket_log;
723 if (bucket_id >= n_buckets)
724 return NULL;
725
726 /* try to find next selem in the same bucket */
727 selem = prev_selem;
728 count = 0;
729 while (selem) {
730 selem = hlist_entry_safe(rcu_dereference(hlist_next_rcu(&selem->map_node)),
731 struct bpf_local_storage_elem, map_node);
732 if (!selem) {
733 /* not found, unlock and go to the next bucket */
734 b = &smap->buckets[bucket_id++];
735 rcu_read_unlock();
736 skip_elems = 0;
737 break;
738 }
739 sk_storage = rcu_dereference(selem->local_storage);
740 if (sk_storage) {
741 info->skip_elems = skip_elems + count;
742 return selem;
743 }
744 count++;
745 }
746
747 for (i = bucket_id; i < (1U << smap->bucket_log); i++) {
748 b = &smap->buckets[i];
749 rcu_read_lock();
750 count = 0;
751 hlist_for_each_entry_rcu(selem, &b->list, map_node) {
752 sk_storage = rcu_dereference(selem->local_storage);
753 if (sk_storage && count >= skip_elems) {
754 info->bucket_id = i;
755 info->skip_elems = count;
756 return selem;
757 }
758 count++;
759 }
760 rcu_read_unlock();
761 skip_elems = 0;
762 }
763
764 info->bucket_id = i;
765 info->skip_elems = 0;
766 return NULL;
767}
768
769static void *bpf_sk_storage_map_seq_start(struct seq_file *seq, loff_t *pos)
770{
771 struct bpf_local_storage_elem *selem;
772
773 selem = bpf_sk_storage_map_seq_find_next(info: seq->private, NULL);
774 if (!selem)
775 return NULL;
776
777 if (*pos == 0)
778 ++*pos;
779 return selem;
780}
781
782static void *bpf_sk_storage_map_seq_next(struct seq_file *seq, void *v,
783 loff_t *pos)
784{
785 struct bpf_iter_seq_sk_storage_map_info *info = seq->private;
786
787 ++*pos;
788 ++info->skip_elems;
789 return bpf_sk_storage_map_seq_find_next(info: seq->private, prev_selem: v);
790}
791
792struct bpf_iter__bpf_sk_storage_map {
793 __bpf_md_ptr(struct bpf_iter_meta *, meta);
794 __bpf_md_ptr(struct bpf_map *, map);
795 __bpf_md_ptr(struct sock *, sk);
796 __bpf_md_ptr(void *, value);
797};
798
799DEFINE_BPF_ITER_FUNC(bpf_sk_storage_map, struct bpf_iter_meta *meta,
800 struct bpf_map *map, struct sock *sk,
801 void *value)
802
803static int __bpf_sk_storage_map_seq_show(struct seq_file *seq,
804 struct bpf_local_storage_elem *selem)
805{
806 struct bpf_iter_seq_sk_storage_map_info *info = seq->private;
807 struct bpf_iter__bpf_sk_storage_map ctx = {};
808 struct bpf_local_storage *sk_storage;
809 struct bpf_iter_meta meta;
810 struct bpf_prog *prog;
811 int ret = 0;
812
813 meta.seq = seq;
814 prog = bpf_iter_get_info(meta: &meta, in_stop: selem == NULL);
815 if (prog) {
816 ctx.meta = &meta;
817 ctx.map = info->map;
818 if (selem) {
819 sk_storage = rcu_dereference(selem->local_storage);
820 ctx.sk = sk_storage->owner;
821 ctx.value = SDATA(selem)->data;
822 }
823 ret = bpf_iter_run_prog(prog, ctx: &ctx);
824 }
825
826 return ret;
827}
828
829static int bpf_sk_storage_map_seq_show(struct seq_file *seq, void *v)
830{
831 return __bpf_sk_storage_map_seq_show(seq, selem: v);
832}
833
834static void bpf_sk_storage_map_seq_stop(struct seq_file *seq, void *v)
835 __releases(RCU)
836{
837 if (!v)
838 (void)__bpf_sk_storage_map_seq_show(seq, selem: v);
839 else
840 rcu_read_unlock();
841}
842
843static int bpf_iter_init_sk_storage_map(void *priv_data,
844 struct bpf_iter_aux_info *aux)
845{
846 struct bpf_iter_seq_sk_storage_map_info *seq_info = priv_data;
847
848 bpf_map_inc_with_uref(map: aux->map);
849 seq_info->map = aux->map;
850 return 0;
851}
852
853static void bpf_iter_fini_sk_storage_map(void *priv_data)
854{
855 struct bpf_iter_seq_sk_storage_map_info *seq_info = priv_data;
856
857 bpf_map_put_with_uref(map: seq_info->map);
858}
859
860static int bpf_iter_attach_map(struct bpf_prog *prog,
861 union bpf_iter_link_info *linfo,
862 struct bpf_iter_aux_info *aux)
863{
864 struct bpf_map *map;
865 int err = -EINVAL;
866
867 if (!linfo->map.map_fd)
868 return -EBADF;
869
870 map = bpf_map_get_with_uref(ufd: linfo->map.map_fd);
871 if (IS_ERR(ptr: map))
872 return PTR_ERR(ptr: map);
873
874 if (map->map_type != BPF_MAP_TYPE_SK_STORAGE)
875 goto put_map;
876
877 if (prog->aux->max_rdwr_access > map->value_size) {
878 err = -EACCES;
879 goto put_map;
880 }
881
882 aux->map = map;
883 return 0;
884
885put_map:
886 bpf_map_put_with_uref(map);
887 return err;
888}
889
890static void bpf_iter_detach_map(struct bpf_iter_aux_info *aux)
891{
892 bpf_map_put_with_uref(map: aux->map);
893}
894
895static const struct seq_operations bpf_sk_storage_map_seq_ops = {
896 .start = bpf_sk_storage_map_seq_start,
897 .next = bpf_sk_storage_map_seq_next,
898 .stop = bpf_sk_storage_map_seq_stop,
899 .show = bpf_sk_storage_map_seq_show,
900};
901
902static const struct bpf_iter_seq_info iter_seq_info = {
903 .seq_ops = &bpf_sk_storage_map_seq_ops,
904 .init_seq_private = bpf_iter_init_sk_storage_map,
905 .fini_seq_private = bpf_iter_fini_sk_storage_map,
906 .seq_priv_size = sizeof(struct bpf_iter_seq_sk_storage_map_info),
907};
908
909static struct bpf_iter_reg bpf_sk_storage_map_reg_info = {
910 .target = "bpf_sk_storage_map",
911 .attach_target = bpf_iter_attach_map,
912 .detach_target = bpf_iter_detach_map,
913 .show_fdinfo = bpf_iter_map_show_fdinfo,
914 .fill_link_info = bpf_iter_map_fill_link_info,
915 .ctx_arg_info_size = 2,
916 .ctx_arg_info = {
917 { offsetof(struct bpf_iter__bpf_sk_storage_map, sk),
918 PTR_TO_BTF_ID_OR_NULL },
919 { offsetof(struct bpf_iter__bpf_sk_storage_map, value),
920 PTR_TO_BUF | PTR_MAYBE_NULL },
921 },
922 .seq_info = &iter_seq_info,
923};
924
925static int __init bpf_sk_storage_map_iter_init(void)
926{
927 bpf_sk_storage_map_reg_info.ctx_arg_info[0].btf_id =
928 btf_sock_ids[BTF_SOCK_TYPE_SOCK];
929 return bpf_iter_reg_target(reg_info: &bpf_sk_storage_map_reg_info);
930}
931late_initcall(bpf_sk_storage_map_iter_init);
932

source code of linux/net/core/bpf_sk_storage.c