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6ac99e8f MKL |
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> | |
8e4597c6 | 9 | #include <linux/btf.h> |
5ce6e77c | 10 | #include <linux/btf_ids.h> |
450af8d0 | 11 | #include <linux/bpf_local_storage.h> |
6ac99e8f MKL |
12 | #include <net/bpf_sk_storage.h> |
13 | #include <net/sock.h> | |
1ed4d924 | 14 | #include <uapi/linux/sock_diag.h> |
6ac99e8f | 15 | #include <uapi/linux/btf.h> |
0fe4b381 | 16 | #include <linux/rcupdate_trace.h> |
6ac99e8f | 17 | |
4cc9ce4e KS |
18 | DEFINE_BPF_STORAGE_CACHE(sk_cache); |
19 | ||
1f00d375 | 20 | static struct bpf_local_storage_data * |
e794bfdd | 21 | bpf_sk_storage_lookup(struct sock *sk, struct bpf_map *map, bool cacheit_lockit) |
6ac99e8f | 22 | { |
1f00d375 KS |
23 | struct bpf_local_storage *sk_storage; |
24 | struct bpf_local_storage_map *smap; | |
6ac99e8f | 25 | |
0fe4b381 KS |
26 | sk_storage = |
27 | rcu_dereference_check(sk->sk_bpf_storage, bpf_rcu_lock_held()); | |
6ac99e8f MKL |
28 | if (!sk_storage) |
29 | return NULL; | |
30 | ||
1f00d375 KS |
31 | smap = (struct bpf_local_storage_map *)map; |
32 | return bpf_local_storage_lookup(sk_storage, smap, cacheit_lockit); | |
6ac99e8f MKL |
33 | } |
34 | ||
e794bfdd | 35 | static int bpf_sk_storage_del(struct sock *sk, struct bpf_map *map) |
6ac99e8f | 36 | { |
1f00d375 | 37 | struct bpf_local_storage_data *sdata; |
6ac99e8f | 38 | |
e794bfdd | 39 | sdata = bpf_sk_storage_lookup(sk, map, false); |
6ac99e8f MKL |
40 | if (!sdata) |
41 | return -ENOENT; | |
42 | ||
dcf456c9 | 43 | bpf_selem_unlink(SELEM(sdata), true); |
6ac99e8f MKL |
44 | |
45 | return 0; | |
46 | } | |
47 | ||
8f51dfc7 | 48 | /* Called by __sk_destruct() & bpf_sk_storage_clone() */ |
6ac99e8f MKL |
49 | void bpf_sk_storage_free(struct sock *sk) |
50 | { | |
1f00d375 KS |
51 | struct bpf_local_storage_elem *selem; |
52 | struct bpf_local_storage *sk_storage; | |
6ac99e8f MKL |
53 | bool free_sk_storage = false; |
54 | struct hlist_node *n; | |
55 | ||
56 | rcu_read_lock(); | |
57 | sk_storage = rcu_dereference(sk->sk_bpf_storage); | |
58 | if (!sk_storage) { | |
59 | rcu_read_unlock(); | |
60 | return; | |
61 | } | |
62 | ||
63 | /* Netiher the bpf_prog nor the bpf-map's syscall | |
64 | * could be modifying the sk_storage->list now. | |
65 | * Thus, no elem can be added-to or deleted-from the | |
66 | * sk_storage->list by the bpf_prog or by the bpf-map's syscall. | |
67 | * | |
1f00d375 | 68 | * It is racing with bpf_local_storage_map_free() alone |
6ac99e8f MKL |
69 | * when unlinking elem from the sk_storage->list and |
70 | * the map's bucket->list. | |
71 | */ | |
72 | raw_spin_lock_bh(&sk_storage->lock); | |
73 | hlist_for_each_entry_safe(selem, n, &sk_storage->list, snode) { | |
74 | /* Always unlink from map before unlinking from | |
75 | * sk_storage. | |
76 | */ | |
1f00d375 | 77 | bpf_selem_unlink_map(selem); |
dcf456c9 KS |
78 | free_sk_storage = bpf_selem_unlink_storage_nolock( |
79 | sk_storage, selem, true, false); | |
6ac99e8f MKL |
80 | } |
81 | raw_spin_unlock_bh(&sk_storage->lock); | |
82 | rcu_read_unlock(); | |
83 | ||
84 | if (free_sk_storage) | |
85 | kfree_rcu(sk_storage, rcu); | |
86 | } | |
87 | ||
e794bfdd | 88 | static void bpf_sk_storage_map_free(struct bpf_map *map) |
f836a56e KS |
89 | { |
90 | struct bpf_local_storage_map *smap; | |
91 | ||
92 | smap = (struct bpf_local_storage_map *)map; | |
93 | bpf_local_storage_cache_idx_free(&sk_cache, smap->cache_idx); | |
bc235cdb | 94 | bpf_local_storage_map_free(smap, NULL); |
6ac99e8f MKL |
95 | } |
96 | ||
e794bfdd | 97 | static struct bpf_map *bpf_sk_storage_map_alloc(union bpf_attr *attr) |
f836a56e KS |
98 | { |
99 | struct bpf_local_storage_map *smap; | |
100 | ||
101 | smap = bpf_local_storage_map_alloc(attr); | |
102 | if (IS_ERR(smap)) | |
103 | return ERR_CAST(smap); | |
104 | ||
105 | smap->cache_idx = bpf_local_storage_cache_idx_get(&sk_cache); | |
6ac99e8f MKL |
106 | return &smap->map; |
107 | } | |
108 | ||
109 | static int notsupp_get_next_key(struct bpf_map *map, void *key, | |
110 | void *next_key) | |
111 | { | |
112 | return -ENOTSUPP; | |
113 | } | |
114 | ||
6ac99e8f MKL |
115 | static void *bpf_fd_sk_storage_lookup_elem(struct bpf_map *map, void *key) |
116 | { | |
1f00d375 | 117 | struct bpf_local_storage_data *sdata; |
6ac99e8f MKL |
118 | struct socket *sock; |
119 | int fd, err; | |
120 | ||
121 | fd = *(int *)key; | |
122 | sock = sockfd_lookup(fd, &err); | |
123 | if (sock) { | |
e794bfdd | 124 | sdata = bpf_sk_storage_lookup(sock->sk, map, true); |
6ac99e8f MKL |
125 | sockfd_put(sock); |
126 | return sdata ? sdata->data : NULL; | |
127 | } | |
128 | ||
129 | return ERR_PTR(err); | |
130 | } | |
131 | ||
132 | static int bpf_fd_sk_storage_update_elem(struct bpf_map *map, void *key, | |
133 | void *value, u64 map_flags) | |
134 | { | |
1f00d375 | 135 | struct bpf_local_storage_data *sdata; |
6ac99e8f MKL |
136 | struct socket *sock; |
137 | int fd, err; | |
138 | ||
139 | fd = *(int *)key; | |
140 | sock = sockfd_lookup(fd, &err); | |
141 | if (sock) { | |
f836a56e KS |
142 | sdata = bpf_local_storage_update( |
143 | sock->sk, (struct bpf_local_storage_map *)map, value, | |
b00fa38a | 144 | map_flags, GFP_ATOMIC); |
6ac99e8f | 145 | sockfd_put(sock); |
71f150f4 | 146 | return PTR_ERR_OR_ZERO(sdata); |
6ac99e8f MKL |
147 | } |
148 | ||
149 | return err; | |
150 | } | |
151 | ||
152 | static int bpf_fd_sk_storage_delete_elem(struct bpf_map *map, void *key) | |
153 | { | |
154 | struct socket *sock; | |
155 | int fd, err; | |
156 | ||
157 | fd = *(int *)key; | |
158 | sock = sockfd_lookup(fd, &err); | |
159 | if (sock) { | |
e794bfdd | 160 | err = bpf_sk_storage_del(sock->sk, map); |
6ac99e8f MKL |
161 | sockfd_put(sock); |
162 | return err; | |
163 | } | |
164 | ||
165 | return err; | |
166 | } | |
167 | ||
1f00d375 | 168 | static struct bpf_local_storage_elem * |
8f51dfc7 | 169 | bpf_sk_storage_clone_elem(struct sock *newsk, |
1f00d375 KS |
170 | struct bpf_local_storage_map *smap, |
171 | struct bpf_local_storage_elem *selem) | |
8f51dfc7 | 172 | { |
1f00d375 | 173 | struct bpf_local_storage_elem *copy_selem; |
8f51dfc7 | 174 | |
b00fa38a | 175 | copy_selem = bpf_selem_alloc(smap, newsk, NULL, true, GFP_ATOMIC); |
8f51dfc7 SF |
176 | if (!copy_selem) |
177 | return NULL; | |
178 | ||
179 | if (map_value_has_spin_lock(&smap->map)) | |
180 | copy_map_value_locked(&smap->map, SDATA(copy_selem)->data, | |
181 | SDATA(selem)->data, true); | |
182 | else | |
183 | copy_map_value(&smap->map, SDATA(copy_selem)->data, | |
184 | SDATA(selem)->data); | |
185 | ||
186 | return copy_selem; | |
187 | } | |
188 | ||
189 | int bpf_sk_storage_clone(const struct sock *sk, struct sock *newsk) | |
190 | { | |
1f00d375 KS |
191 | struct bpf_local_storage *new_sk_storage = NULL; |
192 | struct bpf_local_storage *sk_storage; | |
193 | struct bpf_local_storage_elem *selem; | |
8f51dfc7 SF |
194 | int ret = 0; |
195 | ||
196 | RCU_INIT_POINTER(newsk->sk_bpf_storage, NULL); | |
197 | ||
198 | rcu_read_lock(); | |
199 | sk_storage = rcu_dereference(sk->sk_bpf_storage); | |
200 | ||
201 | if (!sk_storage || hlist_empty(&sk_storage->list)) | |
202 | goto out; | |
203 | ||
204 | hlist_for_each_entry_rcu(selem, &sk_storage->list, snode) { | |
1f00d375 KS |
205 | struct bpf_local_storage_elem *copy_selem; |
206 | struct bpf_local_storage_map *smap; | |
8f51dfc7 SF |
207 | struct bpf_map *map; |
208 | ||
209 | smap = rcu_dereference(SDATA(selem)->smap); | |
210 | if (!(smap->map.map_flags & BPF_F_CLONE)) | |
211 | continue; | |
212 | ||
213 | /* Note that for lockless listeners adding new element | |
1f00d375 | 214 | * here can race with cleanup in bpf_local_storage_map_free. |
8f51dfc7 SF |
215 | * Try to grab map refcnt to make sure that it's still |
216 | * alive and prevent concurrent removal. | |
217 | */ | |
1e0bd5a0 | 218 | map = bpf_map_inc_not_zero(&smap->map); |
8f51dfc7 SF |
219 | if (IS_ERR(map)) |
220 | continue; | |
221 | ||
222 | copy_selem = bpf_sk_storage_clone_elem(newsk, smap, selem); | |
223 | if (!copy_selem) { | |
224 | ret = -ENOMEM; | |
225 | bpf_map_put(map); | |
226 | goto out; | |
227 | } | |
228 | ||
229 | if (new_sk_storage) { | |
1f00d375 KS |
230 | bpf_selem_link_map(smap, copy_selem); |
231 | bpf_selem_link_storage_nolock(new_sk_storage, copy_selem); | |
8f51dfc7 | 232 | } else { |
b00fa38a | 233 | ret = bpf_local_storage_alloc(newsk, smap, copy_selem, GFP_ATOMIC); |
8f51dfc7 SF |
234 | if (ret) { |
235 | kfree(copy_selem); | |
236 | atomic_sub(smap->elem_size, | |
237 | &newsk->sk_omem_alloc); | |
238 | bpf_map_put(map); | |
239 | goto out; | |
240 | } | |
241 | ||
1f00d375 KS |
242 | new_sk_storage = |
243 | rcu_dereference(copy_selem->local_storage); | |
8f51dfc7 SF |
244 | } |
245 | bpf_map_put(map); | |
246 | } | |
247 | ||
248 | out: | |
249 | rcu_read_unlock(); | |
250 | ||
251 | /* In case of an error, don't free anything explicitly here, the | |
252 | * caller is responsible to call bpf_sk_storage_free. | |
253 | */ | |
254 | ||
255 | return ret; | |
256 | } | |
257 | ||
b00fa38a JK |
258 | /* *gfp_flags* is a hidden argument provided by the verifier */ |
259 | BPF_CALL_5(bpf_sk_storage_get, struct bpf_map *, map, struct sock *, sk, | |
260 | void *, value, u64, flags, gfp_t, gfp_flags) | |
6ac99e8f | 261 | { |
1f00d375 | 262 | struct bpf_local_storage_data *sdata; |
6ac99e8f | 263 | |
0fe4b381 | 264 | WARN_ON_ONCE(!bpf_rcu_lock_held()); |
592a3498 | 265 | if (!sk || !sk_fullsock(sk) || flags > BPF_SK_STORAGE_GET_F_CREATE) |
6ac99e8f MKL |
266 | return (unsigned long)NULL; |
267 | ||
e794bfdd | 268 | sdata = bpf_sk_storage_lookup(sk, map, true); |
6ac99e8f MKL |
269 | if (sdata) |
270 | return (unsigned long)sdata->data; | |
271 | ||
272 | if (flags == BPF_SK_STORAGE_GET_F_CREATE && | |
273 | /* Cannot add new elem to a going away sk. | |
274 | * Otherwise, the new elem may become a leak | |
275 | * (and also other memory issues during map | |
276 | * destruction). | |
277 | */ | |
278 | refcount_inc_not_zero(&sk->sk_refcnt)) { | |
f836a56e KS |
279 | sdata = bpf_local_storage_update( |
280 | sk, (struct bpf_local_storage_map *)map, value, | |
b00fa38a | 281 | BPF_NOEXIST, gfp_flags); |
6ac99e8f MKL |
282 | /* sk must be a fullsock (guaranteed by verifier), |
283 | * so sock_gen_put() is unnecessary. | |
284 | */ | |
285 | sock_put(sk); | |
286 | return IS_ERR(sdata) ? | |
287 | (unsigned long)NULL : (unsigned long)sdata->data; | |
288 | } | |
289 | ||
290 | return (unsigned long)NULL; | |
291 | } | |
292 | ||
293 | BPF_CALL_2(bpf_sk_storage_delete, struct bpf_map *, map, struct sock *, sk) | |
294 | { | |
0fe4b381 | 295 | WARN_ON_ONCE(!bpf_rcu_lock_held()); |
592a3498 MKL |
296 | if (!sk || !sk_fullsock(sk)) |
297 | return -EINVAL; | |
298 | ||
6ac99e8f MKL |
299 | if (refcount_inc_not_zero(&sk->sk_refcnt)) { |
300 | int err; | |
301 | ||
e794bfdd | 302 | err = bpf_sk_storage_del(sk, map); |
6ac99e8f MKL |
303 | sock_put(sk); |
304 | return err; | |
305 | } | |
306 | ||
307 | return -ENOENT; | |
308 | } | |
309 | ||
e794bfdd MKL |
310 | static int bpf_sk_storage_charge(struct bpf_local_storage_map *smap, |
311 | void *owner, u32 size) | |
f836a56e | 312 | { |
9e838b02 MKL |
313 | struct sock *sk = (struct sock *)owner; |
314 | ||
315 | /* same check as in sock_kmalloc() */ | |
316 | if (size <= sysctl_optmem_max && | |
317 | atomic_read(&sk->sk_omem_alloc) + size < sysctl_optmem_max) { | |
318 | atomic_add(size, &sk->sk_omem_alloc); | |
319 | return 0; | |
320 | } | |
321 | ||
322 | return -ENOMEM; | |
f836a56e KS |
323 | } |
324 | ||
e794bfdd MKL |
325 | static void bpf_sk_storage_uncharge(struct bpf_local_storage_map *smap, |
326 | void *owner, u32 size) | |
f836a56e KS |
327 | { |
328 | struct sock *sk = owner; | |
329 | ||
330 | atomic_sub(size, &sk->sk_omem_alloc); | |
331 | } | |
332 | ||
333 | static struct bpf_local_storage __rcu ** | |
e794bfdd | 334 | bpf_sk_storage_ptr(void *owner) |
f836a56e KS |
335 | { |
336 | struct sock *sk = owner; | |
337 | ||
338 | return &sk->sk_bpf_storage; | |
339 | } | |
340 | ||
c317ab71 | 341 | BTF_ID_LIST_SINGLE(sk_storage_map_btf_ids, struct, bpf_local_storage_map) |
6ac99e8f | 342 | const struct bpf_map_ops sk_storage_map_ops = { |
f4d05259 | 343 | .map_meta_equal = bpf_map_meta_equal, |
1f00d375 | 344 | .map_alloc_check = bpf_local_storage_map_alloc_check, |
e794bfdd MKL |
345 | .map_alloc = bpf_sk_storage_map_alloc, |
346 | .map_free = bpf_sk_storage_map_free, | |
6ac99e8f MKL |
347 | .map_get_next_key = notsupp_get_next_key, |
348 | .map_lookup_elem = bpf_fd_sk_storage_lookup_elem, | |
349 | .map_update_elem = bpf_fd_sk_storage_update_elem, | |
350 | .map_delete_elem = bpf_fd_sk_storage_delete_elem, | |
1f00d375 | 351 | .map_check_btf = bpf_local_storage_map_check_btf, |
c317ab71 | 352 | .map_btf_id = &sk_storage_map_btf_ids[0], |
e794bfdd MKL |
353 | .map_local_storage_charge = bpf_sk_storage_charge, |
354 | .map_local_storage_uncharge = bpf_sk_storage_uncharge, | |
355 | .map_owner_storage_ptr = bpf_sk_storage_ptr, | |
6ac99e8f MKL |
356 | }; |
357 | ||
358 | const struct bpf_func_proto bpf_sk_storage_get_proto = { | |
359 | .func = bpf_sk_storage_get, | |
360 | .gpl_only = false, | |
361 | .ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL, | |
362 | .arg1_type = ARG_CONST_MAP_PTR, | |
592a3498 | 363 | .arg2_type = ARG_PTR_TO_BTF_ID_SOCK_COMMON, |
6ac99e8f MKL |
364 | .arg3_type = ARG_PTR_TO_MAP_VALUE_OR_NULL, |
365 | .arg4_type = ARG_ANYTHING, | |
366 | }; | |
367 | ||
f7c6cb1d SF |
368 | const struct bpf_func_proto bpf_sk_storage_get_cg_sock_proto = { |
369 | .func = bpf_sk_storage_get, | |
370 | .gpl_only = false, | |
371 | .ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL, | |
372 | .arg1_type = ARG_CONST_MAP_PTR, | |
373 | .arg2_type = ARG_PTR_TO_CTX, /* context is 'struct sock' */ | |
374 | .arg3_type = ARG_PTR_TO_MAP_VALUE_OR_NULL, | |
375 | .arg4_type = ARG_ANYTHING, | |
376 | }; | |
377 | ||
6ac99e8f MKL |
378 | const struct bpf_func_proto bpf_sk_storage_delete_proto = { |
379 | .func = bpf_sk_storage_delete, | |
380 | .gpl_only = false, | |
381 | .ret_type = RET_INTEGER, | |
382 | .arg1_type = ARG_CONST_MAP_PTR, | |
592a3498 | 383 | .arg2_type = ARG_PTR_TO_BTF_ID_SOCK_COMMON, |
30897832 KS |
384 | }; |
385 | ||
8e4597c6 MKL |
386 | static bool bpf_sk_storage_tracing_allowed(const struct bpf_prog *prog) |
387 | { | |
388 | const struct btf *btf_vmlinux; | |
389 | const struct btf_type *t; | |
390 | const char *tname; | |
391 | u32 btf_id; | |
392 | ||
393 | if (prog->aux->dst_prog) | |
394 | return false; | |
395 | ||
396 | /* Ensure the tracing program is not tracing | |
397 | * any bpf_sk_storage*() function and also | |
398 | * use the bpf_sk_storage_(get|delete) helper. | |
399 | */ | |
400 | switch (prog->expected_attach_type) { | |
a50a85e4 | 401 | case BPF_TRACE_ITER: |
8e4597c6 MKL |
402 | case BPF_TRACE_RAW_TP: |
403 | /* bpf_sk_storage has no trace point */ | |
404 | return true; | |
405 | case BPF_TRACE_FENTRY: | |
406 | case BPF_TRACE_FEXIT: | |
407 | btf_vmlinux = bpf_get_btf_vmlinux(); | |
7ada3787 KKD |
408 | if (IS_ERR_OR_NULL(btf_vmlinux)) |
409 | return false; | |
8e4597c6 MKL |
410 | btf_id = prog->aux->attach_btf_id; |
411 | t = btf_type_by_id(btf_vmlinux, btf_id); | |
412 | tname = btf_name_by_offset(btf_vmlinux, t->name_off); | |
413 | return !!strncmp(tname, "bpf_sk_storage", | |
414 | strlen("bpf_sk_storage")); | |
415 | default: | |
416 | return false; | |
417 | } | |
418 | ||
419 | return false; | |
420 | } | |
421 | ||
b00fa38a JK |
422 | /* *gfp_flags* is a hidden argument provided by the verifier */ |
423 | BPF_CALL_5(bpf_sk_storage_get_tracing, struct bpf_map *, map, struct sock *, sk, | |
424 | void *, value, u64, flags, gfp_t, gfp_flags) | |
8e4597c6 | 425 | { |
0fe4b381 | 426 | WARN_ON_ONCE(!bpf_rcu_lock_held()); |
afa79d08 | 427 | if (in_hardirq() || in_nmi()) |
8e4597c6 MKL |
428 | return (unsigned long)NULL; |
429 | ||
b00fa38a JK |
430 | return (unsigned long)____bpf_sk_storage_get(map, sk, value, flags, |
431 | gfp_flags); | |
8e4597c6 MKL |
432 | } |
433 | ||
434 | BPF_CALL_2(bpf_sk_storage_delete_tracing, struct bpf_map *, map, | |
435 | struct sock *, sk) | |
436 | { | |
0fe4b381 | 437 | WARN_ON_ONCE(!bpf_rcu_lock_held()); |
afa79d08 | 438 | if (in_hardirq() || in_nmi()) |
8e4597c6 MKL |
439 | return -EPERM; |
440 | ||
441 | return ____bpf_sk_storage_delete(map, sk); | |
442 | } | |
443 | ||
444 | const struct bpf_func_proto bpf_sk_storage_get_tracing_proto = { | |
445 | .func = bpf_sk_storage_get_tracing, | |
446 | .gpl_only = false, | |
447 | .ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL, | |
448 | .arg1_type = ARG_CONST_MAP_PTR, | |
449 | .arg2_type = ARG_PTR_TO_BTF_ID, | |
450 | .arg2_btf_id = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON], | |
451 | .arg3_type = ARG_PTR_TO_MAP_VALUE_OR_NULL, | |
452 | .arg4_type = ARG_ANYTHING, | |
453 | .allowed = bpf_sk_storage_tracing_allowed, | |
454 | }; | |
455 | ||
456 | const struct bpf_func_proto bpf_sk_storage_delete_tracing_proto = { | |
457 | .func = bpf_sk_storage_delete_tracing, | |
458 | .gpl_only = false, | |
459 | .ret_type = RET_INTEGER, | |
460 | .arg1_type = ARG_CONST_MAP_PTR, | |
461 | .arg2_type = ARG_PTR_TO_BTF_ID, | |
462 | .arg2_btf_id = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON], | |
463 | .allowed = bpf_sk_storage_tracing_allowed, | |
464 | }; | |
465 | ||
1ed4d924 MKL |
466 | struct bpf_sk_storage_diag { |
467 | u32 nr_maps; | |
468 | struct bpf_map *maps[]; | |
469 | }; | |
470 | ||
471 | /* The reply will be like: | |
472 | * INET_DIAG_BPF_SK_STORAGES (nla_nest) | |
473 | * SK_DIAG_BPF_STORAGE (nla_nest) | |
474 | * SK_DIAG_BPF_STORAGE_MAP_ID (nla_put_u32) | |
475 | * SK_DIAG_BPF_STORAGE_MAP_VALUE (nla_reserve_64bit) | |
476 | * SK_DIAG_BPF_STORAGE (nla_nest) | |
477 | * SK_DIAG_BPF_STORAGE_MAP_ID (nla_put_u32) | |
478 | * SK_DIAG_BPF_STORAGE_MAP_VALUE (nla_reserve_64bit) | |
479 | * .... | |
480 | */ | |
481 | static int nla_value_size(u32 value_size) | |
482 | { | |
483 | /* SK_DIAG_BPF_STORAGE (nla_nest) | |
484 | * SK_DIAG_BPF_STORAGE_MAP_ID (nla_put_u32) | |
485 | * SK_DIAG_BPF_STORAGE_MAP_VALUE (nla_reserve_64bit) | |
486 | */ | |
487 | return nla_total_size(0) + nla_total_size(sizeof(u32)) + | |
488 | nla_total_size_64bit(value_size); | |
489 | } | |
490 | ||
491 | void bpf_sk_storage_diag_free(struct bpf_sk_storage_diag *diag) | |
492 | { | |
493 | u32 i; | |
494 | ||
495 | if (!diag) | |
496 | return; | |
497 | ||
498 | for (i = 0; i < diag->nr_maps; i++) | |
499 | bpf_map_put(diag->maps[i]); | |
500 | ||
501 | kfree(diag); | |
502 | } | |
503 | EXPORT_SYMBOL_GPL(bpf_sk_storage_diag_free); | |
504 | ||
505 | static bool diag_check_dup(const struct bpf_sk_storage_diag *diag, | |
506 | const struct bpf_map *map) | |
507 | { | |
508 | u32 i; | |
509 | ||
510 | for (i = 0; i < diag->nr_maps; i++) { | |
511 | if (diag->maps[i] == map) | |
512 | return true; | |
513 | } | |
514 | ||
515 | return false; | |
516 | } | |
517 | ||
518 | struct bpf_sk_storage_diag * | |
519 | bpf_sk_storage_diag_alloc(const struct nlattr *nla_stgs) | |
520 | { | |
521 | struct bpf_sk_storage_diag *diag; | |
522 | struct nlattr *nla; | |
523 | u32 nr_maps = 0; | |
524 | int rem, err; | |
525 | ||
1f00d375 | 526 | /* bpf_local_storage_map is currently limited to CAP_SYS_ADMIN as |
1ed4d924 MKL |
527 | * the map_alloc_check() side also does. |
528 | */ | |
2c78ee89 | 529 | if (!bpf_capable()) |
1ed4d924 MKL |
530 | return ERR_PTR(-EPERM); |
531 | ||
532 | nla_for_each_nested(nla, nla_stgs, rem) { | |
533 | if (nla_type(nla) == SK_DIAG_BPF_STORAGE_REQ_MAP_FD) | |
534 | nr_maps++; | |
535 | } | |
536 | ||
fe0bdaec | 537 | diag = kzalloc(struct_size(diag, maps, nr_maps), GFP_KERNEL); |
1ed4d924 MKL |
538 | if (!diag) |
539 | return ERR_PTR(-ENOMEM); | |
540 | ||
541 | nla_for_each_nested(nla, nla_stgs, rem) { | |
542 | struct bpf_map *map; | |
543 | int map_fd; | |
544 | ||
545 | if (nla_type(nla) != SK_DIAG_BPF_STORAGE_REQ_MAP_FD) | |
546 | continue; | |
547 | ||
548 | map_fd = nla_get_u32(nla); | |
549 | map = bpf_map_get(map_fd); | |
550 | if (IS_ERR(map)) { | |
551 | err = PTR_ERR(map); | |
552 | goto err_free; | |
553 | } | |
554 | if (map->map_type != BPF_MAP_TYPE_SK_STORAGE) { | |
555 | bpf_map_put(map); | |
556 | err = -EINVAL; | |
557 | goto err_free; | |
558 | } | |
559 | if (diag_check_dup(diag, map)) { | |
560 | bpf_map_put(map); | |
561 | err = -EEXIST; | |
562 | goto err_free; | |
563 | } | |
564 | diag->maps[diag->nr_maps++] = map; | |
565 | } | |
566 | ||
567 | return diag; | |
568 | ||
569 | err_free: | |
570 | bpf_sk_storage_diag_free(diag); | |
571 | return ERR_PTR(err); | |
572 | } | |
573 | EXPORT_SYMBOL_GPL(bpf_sk_storage_diag_alloc); | |
574 | ||
1f00d375 | 575 | static int diag_get(struct bpf_local_storage_data *sdata, struct sk_buff *skb) |
1ed4d924 MKL |
576 | { |
577 | struct nlattr *nla_stg, *nla_value; | |
1f00d375 | 578 | struct bpf_local_storage_map *smap; |
1ed4d924 MKL |
579 | |
580 | /* It cannot exceed max nlattr's payload */ | |
1f00d375 | 581 | BUILD_BUG_ON(U16_MAX - NLA_HDRLEN < BPF_LOCAL_STORAGE_MAX_VALUE_SIZE); |
1ed4d924 MKL |
582 | |
583 | nla_stg = nla_nest_start(skb, SK_DIAG_BPF_STORAGE); | |
584 | if (!nla_stg) | |
585 | return -EMSGSIZE; | |
586 | ||
587 | smap = rcu_dereference(sdata->smap); | |
588 | if (nla_put_u32(skb, SK_DIAG_BPF_STORAGE_MAP_ID, smap->map.id)) | |
589 | goto errout; | |
590 | ||
591 | nla_value = nla_reserve_64bit(skb, SK_DIAG_BPF_STORAGE_MAP_VALUE, | |
592 | smap->map.value_size, | |
593 | SK_DIAG_BPF_STORAGE_PAD); | |
594 | if (!nla_value) | |
595 | goto errout; | |
596 | ||
597 | if (map_value_has_spin_lock(&smap->map)) | |
598 | copy_map_value_locked(&smap->map, nla_data(nla_value), | |
599 | sdata->data, true); | |
600 | else | |
601 | copy_map_value(&smap->map, nla_data(nla_value), sdata->data); | |
602 | ||
603 | nla_nest_end(skb, nla_stg); | |
604 | return 0; | |
605 | ||
606 | errout: | |
607 | nla_nest_cancel(skb, nla_stg); | |
608 | return -EMSGSIZE; | |
609 | } | |
610 | ||
611 | static int bpf_sk_storage_diag_put_all(struct sock *sk, struct sk_buff *skb, | |
612 | int stg_array_type, | |
613 | unsigned int *res_diag_size) | |
614 | { | |
615 | /* stg_array_type (e.g. INET_DIAG_BPF_SK_STORAGES) */ | |
616 | unsigned int diag_size = nla_total_size(0); | |
1f00d375 KS |
617 | struct bpf_local_storage *sk_storage; |
618 | struct bpf_local_storage_elem *selem; | |
619 | struct bpf_local_storage_map *smap; | |
1ed4d924 MKL |
620 | struct nlattr *nla_stgs; |
621 | unsigned int saved_len; | |
622 | int err = 0; | |
623 | ||
624 | rcu_read_lock(); | |
625 | ||
626 | sk_storage = rcu_dereference(sk->sk_bpf_storage); | |
627 | if (!sk_storage || hlist_empty(&sk_storage->list)) { | |
628 | rcu_read_unlock(); | |
629 | return 0; | |
630 | } | |
631 | ||
632 | nla_stgs = nla_nest_start(skb, stg_array_type); | |
633 | if (!nla_stgs) | |
634 | /* Continue to learn diag_size */ | |
635 | err = -EMSGSIZE; | |
636 | ||
637 | saved_len = skb->len; | |
638 | hlist_for_each_entry_rcu(selem, &sk_storage->list, snode) { | |
639 | smap = rcu_dereference(SDATA(selem)->smap); | |
640 | diag_size += nla_value_size(smap->map.value_size); | |
641 | ||
642 | if (nla_stgs && diag_get(SDATA(selem), skb)) | |
643 | /* Continue to learn diag_size */ | |
644 | err = -EMSGSIZE; | |
645 | } | |
646 | ||
647 | rcu_read_unlock(); | |
648 | ||
649 | if (nla_stgs) { | |
650 | if (saved_len == skb->len) | |
651 | nla_nest_cancel(skb, nla_stgs); | |
652 | else | |
653 | nla_nest_end(skb, nla_stgs); | |
654 | } | |
655 | ||
656 | if (diag_size == nla_total_size(0)) { | |
657 | *res_diag_size = 0; | |
658 | return 0; | |
659 | } | |
660 | ||
661 | *res_diag_size = diag_size; | |
662 | return err; | |
663 | } | |
664 | ||
665 | int bpf_sk_storage_diag_put(struct bpf_sk_storage_diag *diag, | |
666 | struct sock *sk, struct sk_buff *skb, | |
667 | int stg_array_type, | |
668 | unsigned int *res_diag_size) | |
669 | { | |
670 | /* stg_array_type (e.g. INET_DIAG_BPF_SK_STORAGES) */ | |
671 | unsigned int diag_size = nla_total_size(0); | |
1f00d375 KS |
672 | struct bpf_local_storage *sk_storage; |
673 | struct bpf_local_storage_data *sdata; | |
1ed4d924 MKL |
674 | struct nlattr *nla_stgs; |
675 | unsigned int saved_len; | |
676 | int err = 0; | |
677 | u32 i; | |
678 | ||
679 | *res_diag_size = 0; | |
680 | ||
681 | /* No map has been specified. Dump all. */ | |
682 | if (!diag->nr_maps) | |
683 | return bpf_sk_storage_diag_put_all(sk, skb, stg_array_type, | |
684 | res_diag_size); | |
685 | ||
686 | rcu_read_lock(); | |
687 | sk_storage = rcu_dereference(sk->sk_bpf_storage); | |
688 | if (!sk_storage || hlist_empty(&sk_storage->list)) { | |
689 | rcu_read_unlock(); | |
690 | return 0; | |
691 | } | |
692 | ||
693 | nla_stgs = nla_nest_start(skb, stg_array_type); | |
694 | if (!nla_stgs) | |
695 | /* Continue to learn diag_size */ | |
696 | err = -EMSGSIZE; | |
697 | ||
698 | saved_len = skb->len; | |
699 | for (i = 0; i < diag->nr_maps; i++) { | |
1f00d375 KS |
700 | sdata = bpf_local_storage_lookup(sk_storage, |
701 | (struct bpf_local_storage_map *)diag->maps[i], | |
1ed4d924 MKL |
702 | false); |
703 | ||
704 | if (!sdata) | |
705 | continue; | |
706 | ||
707 | diag_size += nla_value_size(diag->maps[i]->value_size); | |
708 | ||
709 | if (nla_stgs && diag_get(sdata, skb)) | |
710 | /* Continue to learn diag_size */ | |
711 | err = -EMSGSIZE; | |
712 | } | |
713 | rcu_read_unlock(); | |
714 | ||
715 | if (nla_stgs) { | |
716 | if (saved_len == skb->len) | |
717 | nla_nest_cancel(skb, nla_stgs); | |
718 | else | |
719 | nla_nest_end(skb, nla_stgs); | |
720 | } | |
721 | ||
722 | if (diag_size == nla_total_size(0)) { | |
723 | *res_diag_size = 0; | |
724 | return 0; | |
725 | } | |
726 | ||
727 | *res_diag_size = diag_size; | |
728 | return err; | |
729 | } | |
730 | EXPORT_SYMBOL_GPL(bpf_sk_storage_diag_put); | |
5ce6e77c YS |
731 | |
732 | struct bpf_iter_seq_sk_storage_map_info { | |
733 | struct bpf_map *map; | |
734 | unsigned int bucket_id; | |
735 | unsigned skip_elems; | |
736 | }; | |
737 | ||
1f00d375 | 738 | static struct bpf_local_storage_elem * |
5ce6e77c | 739 | bpf_sk_storage_map_seq_find_next(struct bpf_iter_seq_sk_storage_map_info *info, |
1f00d375 | 740 | struct bpf_local_storage_elem *prev_selem) |
c69d2ddb | 741 | __acquires(RCU) __releases(RCU) |
5ce6e77c | 742 | { |
1f00d375 KS |
743 | struct bpf_local_storage *sk_storage; |
744 | struct bpf_local_storage_elem *selem; | |
5ce6e77c | 745 | u32 skip_elems = info->skip_elems; |
1f00d375 | 746 | struct bpf_local_storage_map *smap; |
5ce6e77c YS |
747 | u32 bucket_id = info->bucket_id; |
748 | u32 i, count, n_buckets; | |
1f00d375 | 749 | struct bpf_local_storage_map_bucket *b; |
5ce6e77c | 750 | |
1f00d375 | 751 | smap = (struct bpf_local_storage_map *)info->map; |
5ce6e77c YS |
752 | n_buckets = 1U << smap->bucket_log; |
753 | if (bucket_id >= n_buckets) | |
754 | return NULL; | |
755 | ||
756 | /* try to find next selem in the same bucket */ | |
757 | selem = prev_selem; | |
758 | count = 0; | |
759 | while (selem) { | |
c69d2ddb | 760 | selem = hlist_entry_safe(rcu_dereference(hlist_next_rcu(&selem->map_node)), |
1f00d375 | 761 | struct bpf_local_storage_elem, map_node); |
5ce6e77c YS |
762 | if (!selem) { |
763 | /* not found, unlock and go to the next bucket */ | |
764 | b = &smap->buckets[bucket_id++]; | |
c69d2ddb | 765 | rcu_read_unlock(); |
5ce6e77c YS |
766 | skip_elems = 0; |
767 | break; | |
768 | } | |
c69d2ddb | 769 | sk_storage = rcu_dereference(selem->local_storage); |
5ce6e77c YS |
770 | if (sk_storage) { |
771 | info->skip_elems = skip_elems + count; | |
772 | return selem; | |
773 | } | |
774 | count++; | |
775 | } | |
776 | ||
777 | for (i = bucket_id; i < (1U << smap->bucket_log); i++) { | |
778 | b = &smap->buckets[i]; | |
c69d2ddb | 779 | rcu_read_lock(); |
5ce6e77c | 780 | count = 0; |
c69d2ddb YS |
781 | hlist_for_each_entry_rcu(selem, &b->list, map_node) { |
782 | sk_storage = rcu_dereference(selem->local_storage); | |
5ce6e77c YS |
783 | if (sk_storage && count >= skip_elems) { |
784 | info->bucket_id = i; | |
785 | info->skip_elems = count; | |
786 | return selem; | |
787 | } | |
788 | count++; | |
789 | } | |
c69d2ddb | 790 | rcu_read_unlock(); |
5ce6e77c YS |
791 | skip_elems = 0; |
792 | } | |
793 | ||
794 | info->bucket_id = i; | |
795 | info->skip_elems = 0; | |
796 | return NULL; | |
797 | } | |
798 | ||
799 | static void *bpf_sk_storage_map_seq_start(struct seq_file *seq, loff_t *pos) | |
800 | { | |
1f00d375 | 801 | struct bpf_local_storage_elem *selem; |
5ce6e77c YS |
802 | |
803 | selem = bpf_sk_storage_map_seq_find_next(seq->private, NULL); | |
804 | if (!selem) | |
805 | return NULL; | |
806 | ||
807 | if (*pos == 0) | |
808 | ++*pos; | |
809 | return selem; | |
810 | } | |
811 | ||
812 | static void *bpf_sk_storage_map_seq_next(struct seq_file *seq, void *v, | |
813 | loff_t *pos) | |
814 | { | |
815 | struct bpf_iter_seq_sk_storage_map_info *info = seq->private; | |
816 | ||
817 | ++*pos; | |
818 | ++info->skip_elems; | |
819 | return bpf_sk_storage_map_seq_find_next(seq->private, v); | |
820 | } | |
821 | ||
822 | struct bpf_iter__bpf_sk_storage_map { | |
823 | __bpf_md_ptr(struct bpf_iter_meta *, meta); | |
824 | __bpf_md_ptr(struct bpf_map *, map); | |
825 | __bpf_md_ptr(struct sock *, sk); | |
826 | __bpf_md_ptr(void *, value); | |
827 | }; | |
828 | ||
829 | DEFINE_BPF_ITER_FUNC(bpf_sk_storage_map, struct bpf_iter_meta *meta, | |
830 | struct bpf_map *map, struct sock *sk, | |
831 | void *value) | |
832 | ||
833 | static int __bpf_sk_storage_map_seq_show(struct seq_file *seq, | |
1f00d375 | 834 | struct bpf_local_storage_elem *selem) |
5ce6e77c YS |
835 | { |
836 | struct bpf_iter_seq_sk_storage_map_info *info = seq->private; | |
837 | struct bpf_iter__bpf_sk_storage_map ctx = {}; | |
1f00d375 | 838 | struct bpf_local_storage *sk_storage; |
5ce6e77c YS |
839 | struct bpf_iter_meta meta; |
840 | struct bpf_prog *prog; | |
841 | int ret = 0; | |
842 | ||
843 | meta.seq = seq; | |
844 | prog = bpf_iter_get_info(&meta, selem == NULL); | |
845 | if (prog) { | |
846 | ctx.meta = &meta; | |
847 | ctx.map = info->map; | |
848 | if (selem) { | |
c69d2ddb | 849 | sk_storage = rcu_dereference(selem->local_storage); |
1f00d375 | 850 | ctx.sk = sk_storage->owner; |
5ce6e77c YS |
851 | ctx.value = SDATA(selem)->data; |
852 | } | |
853 | ret = bpf_iter_run_prog(prog, &ctx); | |
854 | } | |
855 | ||
856 | return ret; | |
857 | } | |
858 | ||
859 | static int bpf_sk_storage_map_seq_show(struct seq_file *seq, void *v) | |
860 | { | |
861 | return __bpf_sk_storage_map_seq_show(seq, v); | |
862 | } | |
863 | ||
864 | static void bpf_sk_storage_map_seq_stop(struct seq_file *seq, void *v) | |
c69d2ddb | 865 | __releases(RCU) |
5ce6e77c | 866 | { |
c69d2ddb | 867 | if (!v) |
5ce6e77c | 868 | (void)__bpf_sk_storage_map_seq_show(seq, v); |
c69d2ddb YS |
869 | else |
870 | rcu_read_unlock(); | |
5ce6e77c YS |
871 | } |
872 | ||
873 | static int bpf_iter_init_sk_storage_map(void *priv_data, | |
874 | struct bpf_iter_aux_info *aux) | |
875 | { | |
876 | struct bpf_iter_seq_sk_storage_map_info *seq_info = priv_data; | |
877 | ||
878 | seq_info->map = aux->map; | |
879 | return 0; | |
880 | } | |
881 | ||
5e7b3020 YS |
882 | static int bpf_iter_attach_map(struct bpf_prog *prog, |
883 | union bpf_iter_link_info *linfo, | |
884 | struct bpf_iter_aux_info *aux) | |
5ce6e77c | 885 | { |
5e7b3020 YS |
886 | struct bpf_map *map; |
887 | int err = -EINVAL; | |
888 | ||
889 | if (!linfo->map.map_fd) | |
890 | return -EBADF; | |
891 | ||
892 | map = bpf_map_get_with_uref(linfo->map.map_fd); | |
893 | if (IS_ERR(map)) | |
894 | return PTR_ERR(map); | |
5ce6e77c YS |
895 | |
896 | if (map->map_type != BPF_MAP_TYPE_SK_STORAGE) | |
5e7b3020 | 897 | goto put_map; |
5ce6e77c | 898 | |
5e7b3020 YS |
899 | if (prog->aux->max_rdonly_access > map->value_size) { |
900 | err = -EACCES; | |
901 | goto put_map; | |
902 | } | |
5ce6e77c | 903 | |
5e7b3020 | 904 | aux->map = map; |
5ce6e77c | 905 | return 0; |
5e7b3020 YS |
906 | |
907 | put_map: | |
908 | bpf_map_put_with_uref(map); | |
909 | return err; | |
910 | } | |
911 | ||
912 | static void bpf_iter_detach_map(struct bpf_iter_aux_info *aux) | |
913 | { | |
914 | bpf_map_put_with_uref(aux->map); | |
5ce6e77c YS |
915 | } |
916 | ||
917 | static const struct seq_operations bpf_sk_storage_map_seq_ops = { | |
918 | .start = bpf_sk_storage_map_seq_start, | |
919 | .next = bpf_sk_storage_map_seq_next, | |
920 | .stop = bpf_sk_storage_map_seq_stop, | |
921 | .show = bpf_sk_storage_map_seq_show, | |
922 | }; | |
923 | ||
924 | static const struct bpf_iter_seq_info iter_seq_info = { | |
925 | .seq_ops = &bpf_sk_storage_map_seq_ops, | |
926 | .init_seq_private = bpf_iter_init_sk_storage_map, | |
927 | .fini_seq_private = NULL, | |
928 | .seq_priv_size = sizeof(struct bpf_iter_seq_sk_storage_map_info), | |
929 | }; | |
930 | ||
931 | static struct bpf_iter_reg bpf_sk_storage_map_reg_info = { | |
932 | .target = "bpf_sk_storage_map", | |
5e7b3020 YS |
933 | .attach_target = bpf_iter_attach_map, |
934 | .detach_target = bpf_iter_detach_map, | |
b76f2226 YS |
935 | .show_fdinfo = bpf_iter_map_show_fdinfo, |
936 | .fill_link_info = bpf_iter_map_fill_link_info, | |
5ce6e77c YS |
937 | .ctx_arg_info_size = 2, |
938 | .ctx_arg_info = { | |
939 | { offsetof(struct bpf_iter__bpf_sk_storage_map, sk), | |
940 | PTR_TO_BTF_ID_OR_NULL }, | |
941 | { offsetof(struct bpf_iter__bpf_sk_storage_map, value), | |
20b2aff4 | 942 | PTR_TO_BUF | PTR_MAYBE_NULL }, |
5ce6e77c YS |
943 | }, |
944 | .seq_info = &iter_seq_info, | |
945 | }; | |
946 | ||
947 | static int __init bpf_sk_storage_map_iter_init(void) | |
948 | { | |
949 | bpf_sk_storage_map_reg_info.ctx_arg_info[0].btf_id = | |
950 | btf_sock_ids[BTF_SOCK_TYPE_SOCK]; | |
951 | return bpf_iter_reg_target(&bpf_sk_storage_map_reg_info); | |
952 | } | |
953 | late_initcall(bpf_sk_storage_map_iter_init); |