xref: /linux/kernel/bpf/cgroup.c (revision 1e0731c05c985deb68a97fa44c1adcd3305dda90)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Functions to manage eBPF programs attached to cgroups
4  *
5  * Copyright (c) 2016 Daniel Mack
6  */
7 
8 #include <linux/kernel.h>
9 #include <linux/atomic.h>
10 #include <linux/cgroup.h>
11 #include <linux/filter.h>
12 #include <linux/slab.h>
13 #include <linux/sysctl.h>
14 #include <linux/string.h>
15 #include <linux/bpf.h>
16 #include <linux/bpf-cgroup.h>
17 #include <linux/bpf_lsm.h>
18 #include <linux/bpf_verifier.h>
19 #include <net/sock.h>
20 #include <net/bpf_sk_storage.h>
21 
22 #include "../cgroup/cgroup-internal.h"
23 
24 DEFINE_STATIC_KEY_ARRAY_FALSE(cgroup_bpf_enabled_key, MAX_CGROUP_BPF_ATTACH_TYPE);
25 EXPORT_SYMBOL(cgroup_bpf_enabled_key);
26 
27 /* __always_inline is necessary to prevent indirect call through run_prog
28  * function pointer.
29  */
30 static __always_inline int
31 bpf_prog_run_array_cg(const struct cgroup_bpf *cgrp,
32 		      enum cgroup_bpf_attach_type atype,
33 		      const void *ctx, bpf_prog_run_fn run_prog,
34 		      int retval, u32 *ret_flags)
35 {
36 	const struct bpf_prog_array_item *item;
37 	const struct bpf_prog *prog;
38 	const struct bpf_prog_array *array;
39 	struct bpf_run_ctx *old_run_ctx;
40 	struct bpf_cg_run_ctx run_ctx;
41 	u32 func_ret;
42 
43 	run_ctx.retval = retval;
44 	migrate_disable();
45 	rcu_read_lock();
46 	array = rcu_dereference(cgrp->effective[atype]);
47 	item = &array->items[0];
48 	old_run_ctx = bpf_set_run_ctx(&run_ctx.run_ctx);
49 	while ((prog = READ_ONCE(item->prog))) {
50 		run_ctx.prog_item = item;
51 		func_ret = run_prog(prog, ctx);
52 		if (ret_flags) {
53 			*(ret_flags) |= (func_ret >> 1);
54 			func_ret &= 1;
55 		}
56 		if (!func_ret && !IS_ERR_VALUE((long)run_ctx.retval))
57 			run_ctx.retval = -EPERM;
58 		item++;
59 	}
60 	bpf_reset_run_ctx(old_run_ctx);
61 	rcu_read_unlock();
62 	migrate_enable();
63 	return run_ctx.retval;
64 }
65 
66 unsigned int __cgroup_bpf_run_lsm_sock(const void *ctx,
67 				       const struct bpf_insn *insn)
68 {
69 	const struct bpf_prog *shim_prog;
70 	struct sock *sk;
71 	struct cgroup *cgrp;
72 	int ret = 0;
73 	u64 *args;
74 
75 	args = (u64 *)ctx;
76 	sk = (void *)(unsigned long)args[0];
77 	/*shim_prog = container_of(insn, struct bpf_prog, insnsi);*/
78 	shim_prog = (const struct bpf_prog *)((void *)insn - offsetof(struct bpf_prog, insnsi));
79 
80 	cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
81 	if (likely(cgrp))
82 		ret = bpf_prog_run_array_cg(&cgrp->bpf,
83 					    shim_prog->aux->cgroup_atype,
84 					    ctx, bpf_prog_run, 0, NULL);
85 	return ret;
86 }
87 
88 unsigned int __cgroup_bpf_run_lsm_socket(const void *ctx,
89 					 const struct bpf_insn *insn)
90 {
91 	const struct bpf_prog *shim_prog;
92 	struct socket *sock;
93 	struct cgroup *cgrp;
94 	int ret = 0;
95 	u64 *args;
96 
97 	args = (u64 *)ctx;
98 	sock = (void *)(unsigned long)args[0];
99 	/*shim_prog = container_of(insn, struct bpf_prog, insnsi);*/
100 	shim_prog = (const struct bpf_prog *)((void *)insn - offsetof(struct bpf_prog, insnsi));
101 
102 	cgrp = sock_cgroup_ptr(&sock->sk->sk_cgrp_data);
103 	if (likely(cgrp))
104 		ret = bpf_prog_run_array_cg(&cgrp->bpf,
105 					    shim_prog->aux->cgroup_atype,
106 					    ctx, bpf_prog_run, 0, NULL);
107 	return ret;
108 }
109 
110 unsigned int __cgroup_bpf_run_lsm_current(const void *ctx,
111 					  const struct bpf_insn *insn)
112 {
113 	const struct bpf_prog *shim_prog;
114 	struct cgroup *cgrp;
115 	int ret = 0;
116 
117 	/*shim_prog = container_of(insn, struct bpf_prog, insnsi);*/
118 	shim_prog = (const struct bpf_prog *)((void *)insn - offsetof(struct bpf_prog, insnsi));
119 
120 	/* We rely on trampoline's __bpf_prog_enter_lsm_cgroup to grab RCU read lock. */
121 	cgrp = task_dfl_cgroup(current);
122 	if (likely(cgrp))
123 		ret = bpf_prog_run_array_cg(&cgrp->bpf,
124 					    shim_prog->aux->cgroup_atype,
125 					    ctx, bpf_prog_run, 0, NULL);
126 	return ret;
127 }
128 
129 #ifdef CONFIG_BPF_LSM
130 struct cgroup_lsm_atype {
131 	u32 attach_btf_id;
132 	int refcnt;
133 };
134 
135 static struct cgroup_lsm_atype cgroup_lsm_atype[CGROUP_LSM_NUM];
136 
137 static enum cgroup_bpf_attach_type
138 bpf_cgroup_atype_find(enum bpf_attach_type attach_type, u32 attach_btf_id)
139 {
140 	int i;
141 
142 	lockdep_assert_held(&cgroup_mutex);
143 
144 	if (attach_type != BPF_LSM_CGROUP)
145 		return to_cgroup_bpf_attach_type(attach_type);
146 
147 	for (i = 0; i < ARRAY_SIZE(cgroup_lsm_atype); i++)
148 		if (cgroup_lsm_atype[i].attach_btf_id == attach_btf_id)
149 			return CGROUP_LSM_START + i;
150 
151 	for (i = 0; i < ARRAY_SIZE(cgroup_lsm_atype); i++)
152 		if (cgroup_lsm_atype[i].attach_btf_id == 0)
153 			return CGROUP_LSM_START + i;
154 
155 	return -E2BIG;
156 
157 }
158 
159 void bpf_cgroup_atype_get(u32 attach_btf_id, int cgroup_atype)
160 {
161 	int i = cgroup_atype - CGROUP_LSM_START;
162 
163 	lockdep_assert_held(&cgroup_mutex);
164 
165 	WARN_ON_ONCE(cgroup_lsm_atype[i].attach_btf_id &&
166 		     cgroup_lsm_atype[i].attach_btf_id != attach_btf_id);
167 
168 	cgroup_lsm_atype[i].attach_btf_id = attach_btf_id;
169 	cgroup_lsm_atype[i].refcnt++;
170 }
171 
172 void bpf_cgroup_atype_put(int cgroup_atype)
173 {
174 	int i = cgroup_atype - CGROUP_LSM_START;
175 
176 	cgroup_lock();
177 	if (--cgroup_lsm_atype[i].refcnt <= 0)
178 		cgroup_lsm_atype[i].attach_btf_id = 0;
179 	WARN_ON_ONCE(cgroup_lsm_atype[i].refcnt < 0);
180 	cgroup_unlock();
181 }
182 #else
183 static enum cgroup_bpf_attach_type
184 bpf_cgroup_atype_find(enum bpf_attach_type attach_type, u32 attach_btf_id)
185 {
186 	if (attach_type != BPF_LSM_CGROUP)
187 		return to_cgroup_bpf_attach_type(attach_type);
188 	return -EOPNOTSUPP;
189 }
190 #endif /* CONFIG_BPF_LSM */
191 
192 void cgroup_bpf_offline(struct cgroup *cgrp)
193 {
194 	cgroup_get(cgrp);
195 	percpu_ref_kill(&cgrp->bpf.refcnt);
196 }
197 
198 static void bpf_cgroup_storages_free(struct bpf_cgroup_storage *storages[])
199 {
200 	enum bpf_cgroup_storage_type stype;
201 
202 	for_each_cgroup_storage_type(stype)
203 		bpf_cgroup_storage_free(storages[stype]);
204 }
205 
206 static int bpf_cgroup_storages_alloc(struct bpf_cgroup_storage *storages[],
207 				     struct bpf_cgroup_storage *new_storages[],
208 				     enum bpf_attach_type type,
209 				     struct bpf_prog *prog,
210 				     struct cgroup *cgrp)
211 {
212 	enum bpf_cgroup_storage_type stype;
213 	struct bpf_cgroup_storage_key key;
214 	struct bpf_map *map;
215 
216 	key.cgroup_inode_id = cgroup_id(cgrp);
217 	key.attach_type = type;
218 
219 	for_each_cgroup_storage_type(stype) {
220 		map = prog->aux->cgroup_storage[stype];
221 		if (!map)
222 			continue;
223 
224 		storages[stype] = cgroup_storage_lookup((void *)map, &key, false);
225 		if (storages[stype])
226 			continue;
227 
228 		storages[stype] = bpf_cgroup_storage_alloc(prog, stype);
229 		if (IS_ERR(storages[stype])) {
230 			bpf_cgroup_storages_free(new_storages);
231 			return -ENOMEM;
232 		}
233 
234 		new_storages[stype] = storages[stype];
235 	}
236 
237 	return 0;
238 }
239 
240 static void bpf_cgroup_storages_assign(struct bpf_cgroup_storage *dst[],
241 				       struct bpf_cgroup_storage *src[])
242 {
243 	enum bpf_cgroup_storage_type stype;
244 
245 	for_each_cgroup_storage_type(stype)
246 		dst[stype] = src[stype];
247 }
248 
249 static void bpf_cgroup_storages_link(struct bpf_cgroup_storage *storages[],
250 				     struct cgroup *cgrp,
251 				     enum bpf_attach_type attach_type)
252 {
253 	enum bpf_cgroup_storage_type stype;
254 
255 	for_each_cgroup_storage_type(stype)
256 		bpf_cgroup_storage_link(storages[stype], cgrp, attach_type);
257 }
258 
259 /* Called when bpf_cgroup_link is auto-detached from dying cgroup.
260  * It drops cgroup and bpf_prog refcounts, and marks bpf_link as defunct. It
261  * doesn't free link memory, which will eventually be done by bpf_link's
262  * release() callback, when its last FD is closed.
263  */
264 static void bpf_cgroup_link_auto_detach(struct bpf_cgroup_link *link)
265 {
266 	cgroup_put(link->cgroup);
267 	link->cgroup = NULL;
268 }
269 
270 /**
271  * cgroup_bpf_release() - put references of all bpf programs and
272  *                        release all cgroup bpf data
273  * @work: work structure embedded into the cgroup to modify
274  */
275 static void cgroup_bpf_release(struct work_struct *work)
276 {
277 	struct cgroup *p, *cgrp = container_of(work, struct cgroup,
278 					       bpf.release_work);
279 	struct bpf_prog_array *old_array;
280 	struct list_head *storages = &cgrp->bpf.storages;
281 	struct bpf_cgroup_storage *storage, *stmp;
282 
283 	unsigned int atype;
284 
285 	cgroup_lock();
286 
287 	for (atype = 0; atype < ARRAY_SIZE(cgrp->bpf.progs); atype++) {
288 		struct hlist_head *progs = &cgrp->bpf.progs[atype];
289 		struct bpf_prog_list *pl;
290 		struct hlist_node *pltmp;
291 
292 		hlist_for_each_entry_safe(pl, pltmp, progs, node) {
293 			hlist_del(&pl->node);
294 			if (pl->prog) {
295 				if (pl->prog->expected_attach_type == BPF_LSM_CGROUP)
296 					bpf_trampoline_unlink_cgroup_shim(pl->prog);
297 				bpf_prog_put(pl->prog);
298 			}
299 			if (pl->link) {
300 				if (pl->link->link.prog->expected_attach_type == BPF_LSM_CGROUP)
301 					bpf_trampoline_unlink_cgroup_shim(pl->link->link.prog);
302 				bpf_cgroup_link_auto_detach(pl->link);
303 			}
304 			kfree(pl);
305 			static_branch_dec(&cgroup_bpf_enabled_key[atype]);
306 		}
307 		old_array = rcu_dereference_protected(
308 				cgrp->bpf.effective[atype],
309 				lockdep_is_held(&cgroup_mutex));
310 		bpf_prog_array_free(old_array);
311 	}
312 
313 	list_for_each_entry_safe(storage, stmp, storages, list_cg) {
314 		bpf_cgroup_storage_unlink(storage);
315 		bpf_cgroup_storage_free(storage);
316 	}
317 
318 	cgroup_unlock();
319 
320 	for (p = cgroup_parent(cgrp); p; p = cgroup_parent(p))
321 		cgroup_bpf_put(p);
322 
323 	percpu_ref_exit(&cgrp->bpf.refcnt);
324 	cgroup_put(cgrp);
325 }
326 
327 /**
328  * cgroup_bpf_release_fn() - callback used to schedule releasing
329  *                           of bpf cgroup data
330  * @ref: percpu ref counter structure
331  */
332 static void cgroup_bpf_release_fn(struct percpu_ref *ref)
333 {
334 	struct cgroup *cgrp = container_of(ref, struct cgroup, bpf.refcnt);
335 
336 	INIT_WORK(&cgrp->bpf.release_work, cgroup_bpf_release);
337 	queue_work(system_wq, &cgrp->bpf.release_work);
338 }
339 
340 /* Get underlying bpf_prog of bpf_prog_list entry, regardless if it's through
341  * link or direct prog.
342  */
343 static struct bpf_prog *prog_list_prog(struct bpf_prog_list *pl)
344 {
345 	if (pl->prog)
346 		return pl->prog;
347 	if (pl->link)
348 		return pl->link->link.prog;
349 	return NULL;
350 }
351 
352 /* count number of elements in the list.
353  * it's slow but the list cannot be long
354  */
355 static u32 prog_list_length(struct hlist_head *head)
356 {
357 	struct bpf_prog_list *pl;
358 	u32 cnt = 0;
359 
360 	hlist_for_each_entry(pl, head, node) {
361 		if (!prog_list_prog(pl))
362 			continue;
363 		cnt++;
364 	}
365 	return cnt;
366 }
367 
368 /* if parent has non-overridable prog attached,
369  * disallow attaching new programs to the descendent cgroup.
370  * if parent has overridable or multi-prog, allow attaching
371  */
372 static bool hierarchy_allows_attach(struct cgroup *cgrp,
373 				    enum cgroup_bpf_attach_type atype)
374 {
375 	struct cgroup *p;
376 
377 	p = cgroup_parent(cgrp);
378 	if (!p)
379 		return true;
380 	do {
381 		u32 flags = p->bpf.flags[atype];
382 		u32 cnt;
383 
384 		if (flags & BPF_F_ALLOW_MULTI)
385 			return true;
386 		cnt = prog_list_length(&p->bpf.progs[atype]);
387 		WARN_ON_ONCE(cnt > 1);
388 		if (cnt == 1)
389 			return !!(flags & BPF_F_ALLOW_OVERRIDE);
390 		p = cgroup_parent(p);
391 	} while (p);
392 	return true;
393 }
394 
395 /* compute a chain of effective programs for a given cgroup:
396  * start from the list of programs in this cgroup and add
397  * all parent programs.
398  * Note that parent's F_ALLOW_OVERRIDE-type program is yielding
399  * to programs in this cgroup
400  */
401 static int compute_effective_progs(struct cgroup *cgrp,
402 				   enum cgroup_bpf_attach_type atype,
403 				   struct bpf_prog_array **array)
404 {
405 	struct bpf_prog_array_item *item;
406 	struct bpf_prog_array *progs;
407 	struct bpf_prog_list *pl;
408 	struct cgroup *p = cgrp;
409 	int cnt = 0;
410 
411 	/* count number of effective programs by walking parents */
412 	do {
413 		if (cnt == 0 || (p->bpf.flags[atype] & BPF_F_ALLOW_MULTI))
414 			cnt += prog_list_length(&p->bpf.progs[atype]);
415 		p = cgroup_parent(p);
416 	} while (p);
417 
418 	progs = bpf_prog_array_alloc(cnt, GFP_KERNEL);
419 	if (!progs)
420 		return -ENOMEM;
421 
422 	/* populate the array with effective progs */
423 	cnt = 0;
424 	p = cgrp;
425 	do {
426 		if (cnt > 0 && !(p->bpf.flags[atype] & BPF_F_ALLOW_MULTI))
427 			continue;
428 
429 		hlist_for_each_entry(pl, &p->bpf.progs[atype], node) {
430 			if (!prog_list_prog(pl))
431 				continue;
432 
433 			item = &progs->items[cnt];
434 			item->prog = prog_list_prog(pl);
435 			bpf_cgroup_storages_assign(item->cgroup_storage,
436 						   pl->storage);
437 			cnt++;
438 		}
439 	} while ((p = cgroup_parent(p)));
440 
441 	*array = progs;
442 	return 0;
443 }
444 
445 static void activate_effective_progs(struct cgroup *cgrp,
446 				     enum cgroup_bpf_attach_type atype,
447 				     struct bpf_prog_array *old_array)
448 {
449 	old_array = rcu_replace_pointer(cgrp->bpf.effective[atype], old_array,
450 					lockdep_is_held(&cgroup_mutex));
451 	/* free prog array after grace period, since __cgroup_bpf_run_*()
452 	 * might be still walking the array
453 	 */
454 	bpf_prog_array_free(old_array);
455 }
456 
457 /**
458  * cgroup_bpf_inherit() - inherit effective programs from parent
459  * @cgrp: the cgroup to modify
460  */
461 int cgroup_bpf_inherit(struct cgroup *cgrp)
462 {
463 /* has to use marco instead of const int, since compiler thinks
464  * that array below is variable length
465  */
466 #define	NR ARRAY_SIZE(cgrp->bpf.effective)
467 	struct bpf_prog_array *arrays[NR] = {};
468 	struct cgroup *p;
469 	int ret, i;
470 
471 	ret = percpu_ref_init(&cgrp->bpf.refcnt, cgroup_bpf_release_fn, 0,
472 			      GFP_KERNEL);
473 	if (ret)
474 		return ret;
475 
476 	for (p = cgroup_parent(cgrp); p; p = cgroup_parent(p))
477 		cgroup_bpf_get(p);
478 
479 	for (i = 0; i < NR; i++)
480 		INIT_HLIST_HEAD(&cgrp->bpf.progs[i]);
481 
482 	INIT_LIST_HEAD(&cgrp->bpf.storages);
483 
484 	for (i = 0; i < NR; i++)
485 		if (compute_effective_progs(cgrp, i, &arrays[i]))
486 			goto cleanup;
487 
488 	for (i = 0; i < NR; i++)
489 		activate_effective_progs(cgrp, i, arrays[i]);
490 
491 	return 0;
492 cleanup:
493 	for (i = 0; i < NR; i++)
494 		bpf_prog_array_free(arrays[i]);
495 
496 	for (p = cgroup_parent(cgrp); p; p = cgroup_parent(p))
497 		cgroup_bpf_put(p);
498 
499 	percpu_ref_exit(&cgrp->bpf.refcnt);
500 
501 	return -ENOMEM;
502 }
503 
504 static int update_effective_progs(struct cgroup *cgrp,
505 				  enum cgroup_bpf_attach_type atype)
506 {
507 	struct cgroup_subsys_state *css;
508 	int err;
509 
510 	/* allocate and recompute effective prog arrays */
511 	css_for_each_descendant_pre(css, &cgrp->self) {
512 		struct cgroup *desc = container_of(css, struct cgroup, self);
513 
514 		if (percpu_ref_is_zero(&desc->bpf.refcnt))
515 			continue;
516 
517 		err = compute_effective_progs(desc, atype, &desc->bpf.inactive);
518 		if (err)
519 			goto cleanup;
520 	}
521 
522 	/* all allocations were successful. Activate all prog arrays */
523 	css_for_each_descendant_pre(css, &cgrp->self) {
524 		struct cgroup *desc = container_of(css, struct cgroup, self);
525 
526 		if (percpu_ref_is_zero(&desc->bpf.refcnt)) {
527 			if (unlikely(desc->bpf.inactive)) {
528 				bpf_prog_array_free(desc->bpf.inactive);
529 				desc->bpf.inactive = NULL;
530 			}
531 			continue;
532 		}
533 
534 		activate_effective_progs(desc, atype, desc->bpf.inactive);
535 		desc->bpf.inactive = NULL;
536 	}
537 
538 	return 0;
539 
540 cleanup:
541 	/* oom while computing effective. Free all computed effective arrays
542 	 * since they were not activated
543 	 */
544 	css_for_each_descendant_pre(css, &cgrp->self) {
545 		struct cgroup *desc = container_of(css, struct cgroup, self);
546 
547 		bpf_prog_array_free(desc->bpf.inactive);
548 		desc->bpf.inactive = NULL;
549 	}
550 
551 	return err;
552 }
553 
554 #define BPF_CGROUP_MAX_PROGS 64
555 
556 static struct bpf_prog_list *find_attach_entry(struct hlist_head *progs,
557 					       struct bpf_prog *prog,
558 					       struct bpf_cgroup_link *link,
559 					       struct bpf_prog *replace_prog,
560 					       bool allow_multi)
561 {
562 	struct bpf_prog_list *pl;
563 
564 	/* single-attach case */
565 	if (!allow_multi) {
566 		if (hlist_empty(progs))
567 			return NULL;
568 		return hlist_entry(progs->first, typeof(*pl), node);
569 	}
570 
571 	hlist_for_each_entry(pl, progs, node) {
572 		if (prog && pl->prog == prog && prog != replace_prog)
573 			/* disallow attaching the same prog twice */
574 			return ERR_PTR(-EINVAL);
575 		if (link && pl->link == link)
576 			/* disallow attaching the same link twice */
577 			return ERR_PTR(-EINVAL);
578 	}
579 
580 	/* direct prog multi-attach w/ replacement case */
581 	if (replace_prog) {
582 		hlist_for_each_entry(pl, progs, node) {
583 			if (pl->prog == replace_prog)
584 				/* a match found */
585 				return pl;
586 		}
587 		/* prog to replace not found for cgroup */
588 		return ERR_PTR(-ENOENT);
589 	}
590 
591 	return NULL;
592 }
593 
594 /**
595  * __cgroup_bpf_attach() - Attach the program or the link to a cgroup, and
596  *                         propagate the change to descendants
597  * @cgrp: The cgroup which descendants to traverse
598  * @prog: A program to attach
599  * @link: A link to attach
600  * @replace_prog: Previously attached program to replace if BPF_F_REPLACE is set
601  * @type: Type of attach operation
602  * @flags: Option flags
603  *
604  * Exactly one of @prog or @link can be non-null.
605  * Must be called with cgroup_mutex held.
606  */
607 static int __cgroup_bpf_attach(struct cgroup *cgrp,
608 			       struct bpf_prog *prog, struct bpf_prog *replace_prog,
609 			       struct bpf_cgroup_link *link,
610 			       enum bpf_attach_type type, u32 flags)
611 {
612 	u32 saved_flags = (flags & (BPF_F_ALLOW_OVERRIDE | BPF_F_ALLOW_MULTI));
613 	struct bpf_prog *old_prog = NULL;
614 	struct bpf_cgroup_storage *storage[MAX_BPF_CGROUP_STORAGE_TYPE] = {};
615 	struct bpf_cgroup_storage *new_storage[MAX_BPF_CGROUP_STORAGE_TYPE] = {};
616 	struct bpf_prog *new_prog = prog ? : link->link.prog;
617 	enum cgroup_bpf_attach_type atype;
618 	struct bpf_prog_list *pl;
619 	struct hlist_head *progs;
620 	int err;
621 
622 	if (((flags & BPF_F_ALLOW_OVERRIDE) && (flags & BPF_F_ALLOW_MULTI)) ||
623 	    ((flags & BPF_F_REPLACE) && !(flags & BPF_F_ALLOW_MULTI)))
624 		/* invalid combination */
625 		return -EINVAL;
626 	if (link && (prog || replace_prog))
627 		/* only either link or prog/replace_prog can be specified */
628 		return -EINVAL;
629 	if (!!replace_prog != !!(flags & BPF_F_REPLACE))
630 		/* replace_prog implies BPF_F_REPLACE, and vice versa */
631 		return -EINVAL;
632 
633 	atype = bpf_cgroup_atype_find(type, new_prog->aux->attach_btf_id);
634 	if (atype < 0)
635 		return -EINVAL;
636 
637 	progs = &cgrp->bpf.progs[atype];
638 
639 	if (!hierarchy_allows_attach(cgrp, atype))
640 		return -EPERM;
641 
642 	if (!hlist_empty(progs) && cgrp->bpf.flags[atype] != saved_flags)
643 		/* Disallow attaching non-overridable on top
644 		 * of existing overridable in this cgroup.
645 		 * Disallow attaching multi-prog if overridable or none
646 		 */
647 		return -EPERM;
648 
649 	if (prog_list_length(progs) >= BPF_CGROUP_MAX_PROGS)
650 		return -E2BIG;
651 
652 	pl = find_attach_entry(progs, prog, link, replace_prog,
653 			       flags & BPF_F_ALLOW_MULTI);
654 	if (IS_ERR(pl))
655 		return PTR_ERR(pl);
656 
657 	if (bpf_cgroup_storages_alloc(storage, new_storage, type,
658 				      prog ? : link->link.prog, cgrp))
659 		return -ENOMEM;
660 
661 	if (pl) {
662 		old_prog = pl->prog;
663 	} else {
664 		struct hlist_node *last = NULL;
665 
666 		pl = kmalloc(sizeof(*pl), GFP_KERNEL);
667 		if (!pl) {
668 			bpf_cgroup_storages_free(new_storage);
669 			return -ENOMEM;
670 		}
671 		if (hlist_empty(progs))
672 			hlist_add_head(&pl->node, progs);
673 		else
674 			hlist_for_each(last, progs) {
675 				if (last->next)
676 					continue;
677 				hlist_add_behind(&pl->node, last);
678 				break;
679 			}
680 	}
681 
682 	pl->prog = prog;
683 	pl->link = link;
684 	bpf_cgroup_storages_assign(pl->storage, storage);
685 	cgrp->bpf.flags[atype] = saved_flags;
686 
687 	if (type == BPF_LSM_CGROUP) {
688 		err = bpf_trampoline_link_cgroup_shim(new_prog, atype);
689 		if (err)
690 			goto cleanup;
691 	}
692 
693 	err = update_effective_progs(cgrp, atype);
694 	if (err)
695 		goto cleanup_trampoline;
696 
697 	if (old_prog) {
698 		if (type == BPF_LSM_CGROUP)
699 			bpf_trampoline_unlink_cgroup_shim(old_prog);
700 		bpf_prog_put(old_prog);
701 	} else {
702 		static_branch_inc(&cgroup_bpf_enabled_key[atype]);
703 	}
704 	bpf_cgroup_storages_link(new_storage, cgrp, type);
705 	return 0;
706 
707 cleanup_trampoline:
708 	if (type == BPF_LSM_CGROUP)
709 		bpf_trampoline_unlink_cgroup_shim(new_prog);
710 
711 cleanup:
712 	if (old_prog) {
713 		pl->prog = old_prog;
714 		pl->link = NULL;
715 	}
716 	bpf_cgroup_storages_free(new_storage);
717 	if (!old_prog) {
718 		hlist_del(&pl->node);
719 		kfree(pl);
720 	}
721 	return err;
722 }
723 
724 static int cgroup_bpf_attach(struct cgroup *cgrp,
725 			     struct bpf_prog *prog, struct bpf_prog *replace_prog,
726 			     struct bpf_cgroup_link *link,
727 			     enum bpf_attach_type type,
728 			     u32 flags)
729 {
730 	int ret;
731 
732 	cgroup_lock();
733 	ret = __cgroup_bpf_attach(cgrp, prog, replace_prog, link, type, flags);
734 	cgroup_unlock();
735 	return ret;
736 }
737 
738 /* Swap updated BPF program for given link in effective program arrays across
739  * all descendant cgroups. This function is guaranteed to succeed.
740  */
741 static void replace_effective_prog(struct cgroup *cgrp,
742 				   enum cgroup_bpf_attach_type atype,
743 				   struct bpf_cgroup_link *link)
744 {
745 	struct bpf_prog_array_item *item;
746 	struct cgroup_subsys_state *css;
747 	struct bpf_prog_array *progs;
748 	struct bpf_prog_list *pl;
749 	struct hlist_head *head;
750 	struct cgroup *cg;
751 	int pos;
752 
753 	css_for_each_descendant_pre(css, &cgrp->self) {
754 		struct cgroup *desc = container_of(css, struct cgroup, self);
755 
756 		if (percpu_ref_is_zero(&desc->bpf.refcnt))
757 			continue;
758 
759 		/* find position of link in effective progs array */
760 		for (pos = 0, cg = desc; cg; cg = cgroup_parent(cg)) {
761 			if (pos && !(cg->bpf.flags[atype] & BPF_F_ALLOW_MULTI))
762 				continue;
763 
764 			head = &cg->bpf.progs[atype];
765 			hlist_for_each_entry(pl, head, node) {
766 				if (!prog_list_prog(pl))
767 					continue;
768 				if (pl->link == link)
769 					goto found;
770 				pos++;
771 			}
772 		}
773 found:
774 		BUG_ON(!cg);
775 		progs = rcu_dereference_protected(
776 				desc->bpf.effective[atype],
777 				lockdep_is_held(&cgroup_mutex));
778 		item = &progs->items[pos];
779 		WRITE_ONCE(item->prog, link->link.prog);
780 	}
781 }
782 
783 /**
784  * __cgroup_bpf_replace() - Replace link's program and propagate the change
785  *                          to descendants
786  * @cgrp: The cgroup which descendants to traverse
787  * @link: A link for which to replace BPF program
788  * @new_prog: &struct bpf_prog for the target BPF program with its refcnt
789  *            incremented
790  *
791  * Must be called with cgroup_mutex held.
792  */
793 static int __cgroup_bpf_replace(struct cgroup *cgrp,
794 				struct bpf_cgroup_link *link,
795 				struct bpf_prog *new_prog)
796 {
797 	enum cgroup_bpf_attach_type atype;
798 	struct bpf_prog *old_prog;
799 	struct bpf_prog_list *pl;
800 	struct hlist_head *progs;
801 	bool found = false;
802 
803 	atype = bpf_cgroup_atype_find(link->type, new_prog->aux->attach_btf_id);
804 	if (atype < 0)
805 		return -EINVAL;
806 
807 	progs = &cgrp->bpf.progs[atype];
808 
809 	if (link->link.prog->type != new_prog->type)
810 		return -EINVAL;
811 
812 	hlist_for_each_entry(pl, progs, node) {
813 		if (pl->link == link) {
814 			found = true;
815 			break;
816 		}
817 	}
818 	if (!found)
819 		return -ENOENT;
820 
821 	old_prog = xchg(&link->link.prog, new_prog);
822 	replace_effective_prog(cgrp, atype, link);
823 	bpf_prog_put(old_prog);
824 	return 0;
825 }
826 
827 static int cgroup_bpf_replace(struct bpf_link *link, struct bpf_prog *new_prog,
828 			      struct bpf_prog *old_prog)
829 {
830 	struct bpf_cgroup_link *cg_link;
831 	int ret;
832 
833 	cg_link = container_of(link, struct bpf_cgroup_link, link);
834 
835 	cgroup_lock();
836 	/* link might have been auto-released by dying cgroup, so fail */
837 	if (!cg_link->cgroup) {
838 		ret = -ENOLINK;
839 		goto out_unlock;
840 	}
841 	if (old_prog && link->prog != old_prog) {
842 		ret = -EPERM;
843 		goto out_unlock;
844 	}
845 	ret = __cgroup_bpf_replace(cg_link->cgroup, cg_link, new_prog);
846 out_unlock:
847 	cgroup_unlock();
848 	return ret;
849 }
850 
851 static struct bpf_prog_list *find_detach_entry(struct hlist_head *progs,
852 					       struct bpf_prog *prog,
853 					       struct bpf_cgroup_link *link,
854 					       bool allow_multi)
855 {
856 	struct bpf_prog_list *pl;
857 
858 	if (!allow_multi) {
859 		if (hlist_empty(progs))
860 			/* report error when trying to detach and nothing is attached */
861 			return ERR_PTR(-ENOENT);
862 
863 		/* to maintain backward compatibility NONE and OVERRIDE cgroups
864 		 * allow detaching with invalid FD (prog==NULL) in legacy mode
865 		 */
866 		return hlist_entry(progs->first, typeof(*pl), node);
867 	}
868 
869 	if (!prog && !link)
870 		/* to detach MULTI prog the user has to specify valid FD
871 		 * of the program or link to be detached
872 		 */
873 		return ERR_PTR(-EINVAL);
874 
875 	/* find the prog or link and detach it */
876 	hlist_for_each_entry(pl, progs, node) {
877 		if (pl->prog == prog && pl->link == link)
878 			return pl;
879 	}
880 	return ERR_PTR(-ENOENT);
881 }
882 
883 /**
884  * purge_effective_progs() - After compute_effective_progs fails to alloc new
885  *                           cgrp->bpf.inactive table we can recover by
886  *                           recomputing the array in place.
887  *
888  * @cgrp: The cgroup which descendants to travers
889  * @prog: A program to detach or NULL
890  * @link: A link to detach or NULL
891  * @atype: Type of detach operation
892  */
893 static void purge_effective_progs(struct cgroup *cgrp, struct bpf_prog *prog,
894 				  struct bpf_cgroup_link *link,
895 				  enum cgroup_bpf_attach_type atype)
896 {
897 	struct cgroup_subsys_state *css;
898 	struct bpf_prog_array *progs;
899 	struct bpf_prog_list *pl;
900 	struct hlist_head *head;
901 	struct cgroup *cg;
902 	int pos;
903 
904 	/* recompute effective prog array in place */
905 	css_for_each_descendant_pre(css, &cgrp->self) {
906 		struct cgroup *desc = container_of(css, struct cgroup, self);
907 
908 		if (percpu_ref_is_zero(&desc->bpf.refcnt))
909 			continue;
910 
911 		/* find position of link or prog in effective progs array */
912 		for (pos = 0, cg = desc; cg; cg = cgroup_parent(cg)) {
913 			if (pos && !(cg->bpf.flags[atype] & BPF_F_ALLOW_MULTI))
914 				continue;
915 
916 			head = &cg->bpf.progs[atype];
917 			hlist_for_each_entry(pl, head, node) {
918 				if (!prog_list_prog(pl))
919 					continue;
920 				if (pl->prog == prog && pl->link == link)
921 					goto found;
922 				pos++;
923 			}
924 		}
925 
926 		/* no link or prog match, skip the cgroup of this layer */
927 		continue;
928 found:
929 		progs = rcu_dereference_protected(
930 				desc->bpf.effective[atype],
931 				lockdep_is_held(&cgroup_mutex));
932 
933 		/* Remove the program from the array */
934 		WARN_ONCE(bpf_prog_array_delete_safe_at(progs, pos),
935 			  "Failed to purge a prog from array at index %d", pos);
936 	}
937 }
938 
939 /**
940  * __cgroup_bpf_detach() - Detach the program or link from a cgroup, and
941  *                         propagate the change to descendants
942  * @cgrp: The cgroup which descendants to traverse
943  * @prog: A program to detach or NULL
944  * @link: A link to detach or NULL
945  * @type: Type of detach operation
946  *
947  * At most one of @prog or @link can be non-NULL.
948  * Must be called with cgroup_mutex held.
949  */
950 static int __cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog,
951 			       struct bpf_cgroup_link *link, enum bpf_attach_type type)
952 {
953 	enum cgroup_bpf_attach_type atype;
954 	struct bpf_prog *old_prog;
955 	struct bpf_prog_list *pl;
956 	struct hlist_head *progs;
957 	u32 attach_btf_id = 0;
958 	u32 flags;
959 
960 	if (prog)
961 		attach_btf_id = prog->aux->attach_btf_id;
962 	if (link)
963 		attach_btf_id = link->link.prog->aux->attach_btf_id;
964 
965 	atype = bpf_cgroup_atype_find(type, attach_btf_id);
966 	if (atype < 0)
967 		return -EINVAL;
968 
969 	progs = &cgrp->bpf.progs[atype];
970 	flags = cgrp->bpf.flags[atype];
971 
972 	if (prog && link)
973 		/* only one of prog or link can be specified */
974 		return -EINVAL;
975 
976 	pl = find_detach_entry(progs, prog, link, flags & BPF_F_ALLOW_MULTI);
977 	if (IS_ERR(pl))
978 		return PTR_ERR(pl);
979 
980 	/* mark it deleted, so it's ignored while recomputing effective */
981 	old_prog = pl->prog;
982 	pl->prog = NULL;
983 	pl->link = NULL;
984 
985 	if (update_effective_progs(cgrp, atype)) {
986 		/* if update effective array failed replace the prog with a dummy prog*/
987 		pl->prog = old_prog;
988 		pl->link = link;
989 		purge_effective_progs(cgrp, old_prog, link, atype);
990 	}
991 
992 	/* now can actually delete it from this cgroup list */
993 	hlist_del(&pl->node);
994 
995 	kfree(pl);
996 	if (hlist_empty(progs))
997 		/* last program was detached, reset flags to zero */
998 		cgrp->bpf.flags[atype] = 0;
999 	if (old_prog) {
1000 		if (type == BPF_LSM_CGROUP)
1001 			bpf_trampoline_unlink_cgroup_shim(old_prog);
1002 		bpf_prog_put(old_prog);
1003 	}
1004 	static_branch_dec(&cgroup_bpf_enabled_key[atype]);
1005 	return 0;
1006 }
1007 
1008 static int cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog,
1009 			     enum bpf_attach_type type)
1010 {
1011 	int ret;
1012 
1013 	cgroup_lock();
1014 	ret = __cgroup_bpf_detach(cgrp, prog, NULL, type);
1015 	cgroup_unlock();
1016 	return ret;
1017 }
1018 
1019 /* Must be called with cgroup_mutex held to avoid races. */
1020 static int __cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr,
1021 			      union bpf_attr __user *uattr)
1022 {
1023 	__u32 __user *prog_attach_flags = u64_to_user_ptr(attr->query.prog_attach_flags);
1024 	bool effective_query = attr->query.query_flags & BPF_F_QUERY_EFFECTIVE;
1025 	__u32 __user *prog_ids = u64_to_user_ptr(attr->query.prog_ids);
1026 	enum bpf_attach_type type = attr->query.attach_type;
1027 	enum cgroup_bpf_attach_type from_atype, to_atype;
1028 	enum cgroup_bpf_attach_type atype;
1029 	struct bpf_prog_array *effective;
1030 	int cnt, ret = 0, i;
1031 	int total_cnt = 0;
1032 	u32 flags;
1033 
1034 	if (effective_query && prog_attach_flags)
1035 		return -EINVAL;
1036 
1037 	if (type == BPF_LSM_CGROUP) {
1038 		if (!effective_query && attr->query.prog_cnt &&
1039 		    prog_ids && !prog_attach_flags)
1040 			return -EINVAL;
1041 
1042 		from_atype = CGROUP_LSM_START;
1043 		to_atype = CGROUP_LSM_END;
1044 		flags = 0;
1045 	} else {
1046 		from_atype = to_cgroup_bpf_attach_type(type);
1047 		if (from_atype < 0)
1048 			return -EINVAL;
1049 		to_atype = from_atype;
1050 		flags = cgrp->bpf.flags[from_atype];
1051 	}
1052 
1053 	for (atype = from_atype; atype <= to_atype; atype++) {
1054 		if (effective_query) {
1055 			effective = rcu_dereference_protected(cgrp->bpf.effective[atype],
1056 							      lockdep_is_held(&cgroup_mutex));
1057 			total_cnt += bpf_prog_array_length(effective);
1058 		} else {
1059 			total_cnt += prog_list_length(&cgrp->bpf.progs[atype]);
1060 		}
1061 	}
1062 
1063 	/* always output uattr->query.attach_flags as 0 during effective query */
1064 	flags = effective_query ? 0 : flags;
1065 	if (copy_to_user(&uattr->query.attach_flags, &flags, sizeof(flags)))
1066 		return -EFAULT;
1067 	if (copy_to_user(&uattr->query.prog_cnt, &total_cnt, sizeof(total_cnt)))
1068 		return -EFAULT;
1069 	if (attr->query.prog_cnt == 0 || !prog_ids || !total_cnt)
1070 		/* return early if user requested only program count + flags */
1071 		return 0;
1072 
1073 	if (attr->query.prog_cnt < total_cnt) {
1074 		total_cnt = attr->query.prog_cnt;
1075 		ret = -ENOSPC;
1076 	}
1077 
1078 	for (atype = from_atype; atype <= to_atype && total_cnt; atype++) {
1079 		if (effective_query) {
1080 			effective = rcu_dereference_protected(cgrp->bpf.effective[atype],
1081 							      lockdep_is_held(&cgroup_mutex));
1082 			cnt = min_t(int, bpf_prog_array_length(effective), total_cnt);
1083 			ret = bpf_prog_array_copy_to_user(effective, prog_ids, cnt);
1084 		} else {
1085 			struct hlist_head *progs;
1086 			struct bpf_prog_list *pl;
1087 			struct bpf_prog *prog;
1088 			u32 id;
1089 
1090 			progs = &cgrp->bpf.progs[atype];
1091 			cnt = min_t(int, prog_list_length(progs), total_cnt);
1092 			i = 0;
1093 			hlist_for_each_entry(pl, progs, node) {
1094 				prog = prog_list_prog(pl);
1095 				id = prog->aux->id;
1096 				if (copy_to_user(prog_ids + i, &id, sizeof(id)))
1097 					return -EFAULT;
1098 				if (++i == cnt)
1099 					break;
1100 			}
1101 
1102 			if (prog_attach_flags) {
1103 				flags = cgrp->bpf.flags[atype];
1104 
1105 				for (i = 0; i < cnt; i++)
1106 					if (copy_to_user(prog_attach_flags + i,
1107 							 &flags, sizeof(flags)))
1108 						return -EFAULT;
1109 				prog_attach_flags += cnt;
1110 			}
1111 		}
1112 
1113 		prog_ids += cnt;
1114 		total_cnt -= cnt;
1115 	}
1116 	return ret;
1117 }
1118 
1119 static int cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr,
1120 			    union bpf_attr __user *uattr)
1121 {
1122 	int ret;
1123 
1124 	cgroup_lock();
1125 	ret = __cgroup_bpf_query(cgrp, attr, uattr);
1126 	cgroup_unlock();
1127 	return ret;
1128 }
1129 
1130 int cgroup_bpf_prog_attach(const union bpf_attr *attr,
1131 			   enum bpf_prog_type ptype, struct bpf_prog *prog)
1132 {
1133 	struct bpf_prog *replace_prog = NULL;
1134 	struct cgroup *cgrp;
1135 	int ret;
1136 
1137 	cgrp = cgroup_get_from_fd(attr->target_fd);
1138 	if (IS_ERR(cgrp))
1139 		return PTR_ERR(cgrp);
1140 
1141 	if ((attr->attach_flags & BPF_F_ALLOW_MULTI) &&
1142 	    (attr->attach_flags & BPF_F_REPLACE)) {
1143 		replace_prog = bpf_prog_get_type(attr->replace_bpf_fd, ptype);
1144 		if (IS_ERR(replace_prog)) {
1145 			cgroup_put(cgrp);
1146 			return PTR_ERR(replace_prog);
1147 		}
1148 	}
1149 
1150 	ret = cgroup_bpf_attach(cgrp, prog, replace_prog, NULL,
1151 				attr->attach_type, attr->attach_flags);
1152 
1153 	if (replace_prog)
1154 		bpf_prog_put(replace_prog);
1155 	cgroup_put(cgrp);
1156 	return ret;
1157 }
1158 
1159 int cgroup_bpf_prog_detach(const union bpf_attr *attr, enum bpf_prog_type ptype)
1160 {
1161 	struct bpf_prog *prog;
1162 	struct cgroup *cgrp;
1163 	int ret;
1164 
1165 	cgrp = cgroup_get_from_fd(attr->target_fd);
1166 	if (IS_ERR(cgrp))
1167 		return PTR_ERR(cgrp);
1168 
1169 	prog = bpf_prog_get_type(attr->attach_bpf_fd, ptype);
1170 	if (IS_ERR(prog))
1171 		prog = NULL;
1172 
1173 	ret = cgroup_bpf_detach(cgrp, prog, attr->attach_type);
1174 	if (prog)
1175 		bpf_prog_put(prog);
1176 
1177 	cgroup_put(cgrp);
1178 	return ret;
1179 }
1180 
1181 static void bpf_cgroup_link_release(struct bpf_link *link)
1182 {
1183 	struct bpf_cgroup_link *cg_link =
1184 		container_of(link, struct bpf_cgroup_link, link);
1185 	struct cgroup *cg;
1186 
1187 	/* link might have been auto-detached by dying cgroup already,
1188 	 * in that case our work is done here
1189 	 */
1190 	if (!cg_link->cgroup)
1191 		return;
1192 
1193 	cgroup_lock();
1194 
1195 	/* re-check cgroup under lock again */
1196 	if (!cg_link->cgroup) {
1197 		cgroup_unlock();
1198 		return;
1199 	}
1200 
1201 	WARN_ON(__cgroup_bpf_detach(cg_link->cgroup, NULL, cg_link,
1202 				    cg_link->type));
1203 	if (cg_link->type == BPF_LSM_CGROUP)
1204 		bpf_trampoline_unlink_cgroup_shim(cg_link->link.prog);
1205 
1206 	cg = cg_link->cgroup;
1207 	cg_link->cgroup = NULL;
1208 
1209 	cgroup_unlock();
1210 
1211 	cgroup_put(cg);
1212 }
1213 
1214 static void bpf_cgroup_link_dealloc(struct bpf_link *link)
1215 {
1216 	struct bpf_cgroup_link *cg_link =
1217 		container_of(link, struct bpf_cgroup_link, link);
1218 
1219 	kfree(cg_link);
1220 }
1221 
1222 static int bpf_cgroup_link_detach(struct bpf_link *link)
1223 {
1224 	bpf_cgroup_link_release(link);
1225 
1226 	return 0;
1227 }
1228 
1229 static void bpf_cgroup_link_show_fdinfo(const struct bpf_link *link,
1230 					struct seq_file *seq)
1231 {
1232 	struct bpf_cgroup_link *cg_link =
1233 		container_of(link, struct bpf_cgroup_link, link);
1234 	u64 cg_id = 0;
1235 
1236 	cgroup_lock();
1237 	if (cg_link->cgroup)
1238 		cg_id = cgroup_id(cg_link->cgroup);
1239 	cgroup_unlock();
1240 
1241 	seq_printf(seq,
1242 		   "cgroup_id:\t%llu\n"
1243 		   "attach_type:\t%d\n",
1244 		   cg_id,
1245 		   cg_link->type);
1246 }
1247 
1248 static int bpf_cgroup_link_fill_link_info(const struct bpf_link *link,
1249 					  struct bpf_link_info *info)
1250 {
1251 	struct bpf_cgroup_link *cg_link =
1252 		container_of(link, struct bpf_cgroup_link, link);
1253 	u64 cg_id = 0;
1254 
1255 	cgroup_lock();
1256 	if (cg_link->cgroup)
1257 		cg_id = cgroup_id(cg_link->cgroup);
1258 	cgroup_unlock();
1259 
1260 	info->cgroup.cgroup_id = cg_id;
1261 	info->cgroup.attach_type = cg_link->type;
1262 	return 0;
1263 }
1264 
1265 static const struct bpf_link_ops bpf_cgroup_link_lops = {
1266 	.release = bpf_cgroup_link_release,
1267 	.dealloc = bpf_cgroup_link_dealloc,
1268 	.detach = bpf_cgroup_link_detach,
1269 	.update_prog = cgroup_bpf_replace,
1270 	.show_fdinfo = bpf_cgroup_link_show_fdinfo,
1271 	.fill_link_info = bpf_cgroup_link_fill_link_info,
1272 };
1273 
1274 int cgroup_bpf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
1275 {
1276 	struct bpf_link_primer link_primer;
1277 	struct bpf_cgroup_link *link;
1278 	struct cgroup *cgrp;
1279 	int err;
1280 
1281 	if (attr->link_create.flags)
1282 		return -EINVAL;
1283 
1284 	cgrp = cgroup_get_from_fd(attr->link_create.target_fd);
1285 	if (IS_ERR(cgrp))
1286 		return PTR_ERR(cgrp);
1287 
1288 	link = kzalloc(sizeof(*link), GFP_USER);
1289 	if (!link) {
1290 		err = -ENOMEM;
1291 		goto out_put_cgroup;
1292 	}
1293 	bpf_link_init(&link->link, BPF_LINK_TYPE_CGROUP, &bpf_cgroup_link_lops,
1294 		      prog);
1295 	link->cgroup = cgrp;
1296 	link->type = attr->link_create.attach_type;
1297 
1298 	err = bpf_link_prime(&link->link, &link_primer);
1299 	if (err) {
1300 		kfree(link);
1301 		goto out_put_cgroup;
1302 	}
1303 
1304 	err = cgroup_bpf_attach(cgrp, NULL, NULL, link,
1305 				link->type, BPF_F_ALLOW_MULTI);
1306 	if (err) {
1307 		bpf_link_cleanup(&link_primer);
1308 		goto out_put_cgroup;
1309 	}
1310 
1311 	return bpf_link_settle(&link_primer);
1312 
1313 out_put_cgroup:
1314 	cgroup_put(cgrp);
1315 	return err;
1316 }
1317 
1318 int cgroup_bpf_prog_query(const union bpf_attr *attr,
1319 			  union bpf_attr __user *uattr)
1320 {
1321 	struct cgroup *cgrp;
1322 	int ret;
1323 
1324 	cgrp = cgroup_get_from_fd(attr->query.target_fd);
1325 	if (IS_ERR(cgrp))
1326 		return PTR_ERR(cgrp);
1327 
1328 	ret = cgroup_bpf_query(cgrp, attr, uattr);
1329 
1330 	cgroup_put(cgrp);
1331 	return ret;
1332 }
1333 
1334 /**
1335  * __cgroup_bpf_run_filter_skb() - Run a program for packet filtering
1336  * @sk: The socket sending or receiving traffic
1337  * @skb: The skb that is being sent or received
1338  * @atype: The type of program to be executed
1339  *
1340  * If no socket is passed, or the socket is not of type INET or INET6,
1341  * this function does nothing and returns 0.
1342  *
1343  * The program type passed in via @type must be suitable for network
1344  * filtering. No further check is performed to assert that.
1345  *
1346  * For egress packets, this function can return:
1347  *   NET_XMIT_SUCCESS    (0)	- continue with packet output
1348  *   NET_XMIT_DROP       (1)	- drop packet and notify TCP to call cwr
1349  *   NET_XMIT_CN         (2)	- continue with packet output and notify TCP
1350  *				  to call cwr
1351  *   -err			- drop packet
1352  *
1353  * For ingress packets, this function will return -EPERM if any
1354  * attached program was found and if it returned != 1 during execution.
1355  * Otherwise 0 is returned.
1356  */
1357 int __cgroup_bpf_run_filter_skb(struct sock *sk,
1358 				struct sk_buff *skb,
1359 				enum cgroup_bpf_attach_type atype)
1360 {
1361 	unsigned int offset = skb->data - skb_network_header(skb);
1362 	struct sock *save_sk;
1363 	void *saved_data_end;
1364 	struct cgroup *cgrp;
1365 	int ret;
1366 
1367 	if (!sk || !sk_fullsock(sk))
1368 		return 0;
1369 
1370 	if (sk->sk_family != AF_INET && sk->sk_family != AF_INET6)
1371 		return 0;
1372 
1373 	cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
1374 	save_sk = skb->sk;
1375 	skb->sk = sk;
1376 	__skb_push(skb, offset);
1377 
1378 	/* compute pointers for the bpf prog */
1379 	bpf_compute_and_save_data_end(skb, &saved_data_end);
1380 
1381 	if (atype == CGROUP_INET_EGRESS) {
1382 		u32 flags = 0;
1383 		bool cn;
1384 
1385 		ret = bpf_prog_run_array_cg(&cgrp->bpf, atype, skb,
1386 					    __bpf_prog_run_save_cb, 0, &flags);
1387 
1388 		/* Return values of CGROUP EGRESS BPF programs are:
1389 		 *   0: drop packet
1390 		 *   1: keep packet
1391 		 *   2: drop packet and cn
1392 		 *   3: keep packet and cn
1393 		 *
1394 		 * The returned value is then converted to one of the NET_XMIT
1395 		 * or an error code that is then interpreted as drop packet
1396 		 * (and no cn):
1397 		 *   0: NET_XMIT_SUCCESS  skb should be transmitted
1398 		 *   1: NET_XMIT_DROP     skb should be dropped and cn
1399 		 *   2: NET_XMIT_CN       skb should be transmitted and cn
1400 		 *   3: -err              skb should be dropped
1401 		 */
1402 
1403 		cn = flags & BPF_RET_SET_CN;
1404 		if (ret && !IS_ERR_VALUE((long)ret))
1405 			ret = -EFAULT;
1406 		if (!ret)
1407 			ret = (cn ? NET_XMIT_CN : NET_XMIT_SUCCESS);
1408 		else
1409 			ret = (cn ? NET_XMIT_DROP : ret);
1410 	} else {
1411 		ret = bpf_prog_run_array_cg(&cgrp->bpf, atype,
1412 					    skb, __bpf_prog_run_save_cb, 0,
1413 					    NULL);
1414 		if (ret && !IS_ERR_VALUE((long)ret))
1415 			ret = -EFAULT;
1416 	}
1417 	bpf_restore_data_end(skb, saved_data_end);
1418 	__skb_pull(skb, offset);
1419 	skb->sk = save_sk;
1420 
1421 	return ret;
1422 }
1423 EXPORT_SYMBOL(__cgroup_bpf_run_filter_skb);
1424 
1425 /**
1426  * __cgroup_bpf_run_filter_sk() - Run a program on a sock
1427  * @sk: sock structure to manipulate
1428  * @atype: The type of program to be executed
1429  *
1430  * socket is passed is expected to be of type INET or INET6.
1431  *
1432  * The program type passed in via @type must be suitable for sock
1433  * filtering. No further check is performed to assert that.
1434  *
1435  * This function will return %-EPERM if any if an attached program was found
1436  * and if it returned != 1 during execution. In all other cases, 0 is returned.
1437  */
1438 int __cgroup_bpf_run_filter_sk(struct sock *sk,
1439 			       enum cgroup_bpf_attach_type atype)
1440 {
1441 	struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
1442 
1443 	return bpf_prog_run_array_cg(&cgrp->bpf, atype, sk, bpf_prog_run, 0,
1444 				     NULL);
1445 }
1446 EXPORT_SYMBOL(__cgroup_bpf_run_filter_sk);
1447 
1448 /**
1449  * __cgroup_bpf_run_filter_sock_addr() - Run a program on a sock and
1450  *                                       provided by user sockaddr
1451  * @sk: sock struct that will use sockaddr
1452  * @uaddr: sockaddr struct provided by user
1453  * @atype: The type of program to be executed
1454  * @t_ctx: Pointer to attach type specific context
1455  * @flags: Pointer to u32 which contains higher bits of BPF program
1456  *         return value (OR'ed together).
1457  *
1458  * socket is expected to be of type INET or INET6.
1459  *
1460  * This function will return %-EPERM if an attached program is found and
1461  * returned value != 1 during execution. In all other cases, 0 is returned.
1462  */
1463 int __cgroup_bpf_run_filter_sock_addr(struct sock *sk,
1464 				      struct sockaddr *uaddr,
1465 				      enum cgroup_bpf_attach_type atype,
1466 				      void *t_ctx,
1467 				      u32 *flags)
1468 {
1469 	struct bpf_sock_addr_kern ctx = {
1470 		.sk = sk,
1471 		.uaddr = uaddr,
1472 		.t_ctx = t_ctx,
1473 	};
1474 	struct sockaddr_storage unspec;
1475 	struct cgroup *cgrp;
1476 
1477 	/* Check socket family since not all sockets represent network
1478 	 * endpoint (e.g. AF_UNIX).
1479 	 */
1480 	if (sk->sk_family != AF_INET && sk->sk_family != AF_INET6)
1481 		return 0;
1482 
1483 	if (!ctx.uaddr) {
1484 		memset(&unspec, 0, sizeof(unspec));
1485 		ctx.uaddr = (struct sockaddr *)&unspec;
1486 	}
1487 
1488 	cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
1489 	return bpf_prog_run_array_cg(&cgrp->bpf, atype, &ctx, bpf_prog_run,
1490 				     0, flags);
1491 }
1492 EXPORT_SYMBOL(__cgroup_bpf_run_filter_sock_addr);
1493 
1494 /**
1495  * __cgroup_bpf_run_filter_sock_ops() - Run a program on a sock
1496  * @sk: socket to get cgroup from
1497  * @sock_ops: bpf_sock_ops_kern struct to pass to program. Contains
1498  * sk with connection information (IP addresses, etc.) May not contain
1499  * cgroup info if it is a req sock.
1500  * @atype: The type of program to be executed
1501  *
1502  * socket passed is expected to be of type INET or INET6.
1503  *
1504  * The program type passed in via @type must be suitable for sock_ops
1505  * filtering. No further check is performed to assert that.
1506  *
1507  * This function will return %-EPERM if any if an attached program was found
1508  * and if it returned != 1 during execution. In all other cases, 0 is returned.
1509  */
1510 int __cgroup_bpf_run_filter_sock_ops(struct sock *sk,
1511 				     struct bpf_sock_ops_kern *sock_ops,
1512 				     enum cgroup_bpf_attach_type atype)
1513 {
1514 	struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
1515 
1516 	return bpf_prog_run_array_cg(&cgrp->bpf, atype, sock_ops, bpf_prog_run,
1517 				     0, NULL);
1518 }
1519 EXPORT_SYMBOL(__cgroup_bpf_run_filter_sock_ops);
1520 
1521 int __cgroup_bpf_check_dev_permission(short dev_type, u32 major, u32 minor,
1522 				      short access, enum cgroup_bpf_attach_type atype)
1523 {
1524 	struct cgroup *cgrp;
1525 	struct bpf_cgroup_dev_ctx ctx = {
1526 		.access_type = (access << 16) | dev_type,
1527 		.major = major,
1528 		.minor = minor,
1529 	};
1530 	int ret;
1531 
1532 	rcu_read_lock();
1533 	cgrp = task_dfl_cgroup(current);
1534 	ret = bpf_prog_run_array_cg(&cgrp->bpf, atype, &ctx, bpf_prog_run, 0,
1535 				    NULL);
1536 	rcu_read_unlock();
1537 
1538 	return ret;
1539 }
1540 
1541 BPF_CALL_2(bpf_get_local_storage, struct bpf_map *, map, u64, flags)
1542 {
1543 	/* flags argument is not used now,
1544 	 * but provides an ability to extend the API.
1545 	 * verifier checks that its value is correct.
1546 	 */
1547 	enum bpf_cgroup_storage_type stype = cgroup_storage_type(map);
1548 	struct bpf_cgroup_storage *storage;
1549 	struct bpf_cg_run_ctx *ctx;
1550 	void *ptr;
1551 
1552 	/* get current cgroup storage from BPF run context */
1553 	ctx = container_of(current->bpf_ctx, struct bpf_cg_run_ctx, run_ctx);
1554 	storage = ctx->prog_item->cgroup_storage[stype];
1555 
1556 	if (stype == BPF_CGROUP_STORAGE_SHARED)
1557 		ptr = &READ_ONCE(storage->buf)->data[0];
1558 	else
1559 		ptr = this_cpu_ptr(storage->percpu_buf);
1560 
1561 	return (unsigned long)ptr;
1562 }
1563 
1564 const struct bpf_func_proto bpf_get_local_storage_proto = {
1565 	.func		= bpf_get_local_storage,
1566 	.gpl_only	= false,
1567 	.ret_type	= RET_PTR_TO_MAP_VALUE,
1568 	.arg1_type	= ARG_CONST_MAP_PTR,
1569 	.arg2_type	= ARG_ANYTHING,
1570 };
1571 
1572 BPF_CALL_0(bpf_get_retval)
1573 {
1574 	struct bpf_cg_run_ctx *ctx =
1575 		container_of(current->bpf_ctx, struct bpf_cg_run_ctx, run_ctx);
1576 
1577 	return ctx->retval;
1578 }
1579 
1580 const struct bpf_func_proto bpf_get_retval_proto = {
1581 	.func		= bpf_get_retval,
1582 	.gpl_only	= false,
1583 	.ret_type	= RET_INTEGER,
1584 };
1585 
1586 BPF_CALL_1(bpf_set_retval, int, retval)
1587 {
1588 	struct bpf_cg_run_ctx *ctx =
1589 		container_of(current->bpf_ctx, struct bpf_cg_run_ctx, run_ctx);
1590 
1591 	ctx->retval = retval;
1592 	return 0;
1593 }
1594 
1595 const struct bpf_func_proto bpf_set_retval_proto = {
1596 	.func		= bpf_set_retval,
1597 	.gpl_only	= false,
1598 	.ret_type	= RET_INTEGER,
1599 	.arg1_type	= ARG_ANYTHING,
1600 };
1601 
1602 static const struct bpf_func_proto *
1603 cgroup_dev_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
1604 {
1605 	const struct bpf_func_proto *func_proto;
1606 
1607 	func_proto = cgroup_common_func_proto(func_id, prog);
1608 	if (func_proto)
1609 		return func_proto;
1610 
1611 	func_proto = cgroup_current_func_proto(func_id, prog);
1612 	if (func_proto)
1613 		return func_proto;
1614 
1615 	switch (func_id) {
1616 	case BPF_FUNC_perf_event_output:
1617 		return &bpf_event_output_data_proto;
1618 	default:
1619 		return bpf_base_func_proto(func_id);
1620 	}
1621 }
1622 
1623 static bool cgroup_dev_is_valid_access(int off, int size,
1624 				       enum bpf_access_type type,
1625 				       const struct bpf_prog *prog,
1626 				       struct bpf_insn_access_aux *info)
1627 {
1628 	const int size_default = sizeof(__u32);
1629 
1630 	if (type == BPF_WRITE)
1631 		return false;
1632 
1633 	if (off < 0 || off + size > sizeof(struct bpf_cgroup_dev_ctx))
1634 		return false;
1635 	/* The verifier guarantees that size > 0. */
1636 	if (off % size != 0)
1637 		return false;
1638 
1639 	switch (off) {
1640 	case bpf_ctx_range(struct bpf_cgroup_dev_ctx, access_type):
1641 		bpf_ctx_record_field_size(info, size_default);
1642 		if (!bpf_ctx_narrow_access_ok(off, size, size_default))
1643 			return false;
1644 		break;
1645 	default:
1646 		if (size != size_default)
1647 			return false;
1648 	}
1649 
1650 	return true;
1651 }
1652 
1653 const struct bpf_prog_ops cg_dev_prog_ops = {
1654 };
1655 
1656 const struct bpf_verifier_ops cg_dev_verifier_ops = {
1657 	.get_func_proto		= cgroup_dev_func_proto,
1658 	.is_valid_access	= cgroup_dev_is_valid_access,
1659 };
1660 
1661 /**
1662  * __cgroup_bpf_run_filter_sysctl - Run a program on sysctl
1663  *
1664  * @head: sysctl table header
1665  * @table: sysctl table
1666  * @write: sysctl is being read (= 0) or written (= 1)
1667  * @buf: pointer to buffer (in and out)
1668  * @pcount: value-result argument: value is size of buffer pointed to by @buf,
1669  *	result is size of @new_buf if program set new value, initial value
1670  *	otherwise
1671  * @ppos: value-result argument: value is position at which read from or write
1672  *	to sysctl is happening, result is new position if program overrode it,
1673  *	initial value otherwise
1674  * @atype: type of program to be executed
1675  *
1676  * Program is run when sysctl is being accessed, either read or written, and
1677  * can allow or deny such access.
1678  *
1679  * This function will return %-EPERM if an attached program is found and
1680  * returned value != 1 during execution. In all other cases 0 is returned.
1681  */
1682 int __cgroup_bpf_run_filter_sysctl(struct ctl_table_header *head,
1683 				   struct ctl_table *table, int write,
1684 				   char **buf, size_t *pcount, loff_t *ppos,
1685 				   enum cgroup_bpf_attach_type atype)
1686 {
1687 	struct bpf_sysctl_kern ctx = {
1688 		.head = head,
1689 		.table = table,
1690 		.write = write,
1691 		.ppos = ppos,
1692 		.cur_val = NULL,
1693 		.cur_len = PAGE_SIZE,
1694 		.new_val = NULL,
1695 		.new_len = 0,
1696 		.new_updated = 0,
1697 	};
1698 	struct cgroup *cgrp;
1699 	loff_t pos = 0;
1700 	int ret;
1701 
1702 	ctx.cur_val = kmalloc_track_caller(ctx.cur_len, GFP_KERNEL);
1703 	if (!ctx.cur_val ||
1704 	    table->proc_handler(table, 0, ctx.cur_val, &ctx.cur_len, &pos)) {
1705 		/* Let BPF program decide how to proceed. */
1706 		ctx.cur_len = 0;
1707 	}
1708 
1709 	if (write && *buf && *pcount) {
1710 		/* BPF program should be able to override new value with a
1711 		 * buffer bigger than provided by user.
1712 		 */
1713 		ctx.new_val = kmalloc_track_caller(PAGE_SIZE, GFP_KERNEL);
1714 		ctx.new_len = min_t(size_t, PAGE_SIZE, *pcount);
1715 		if (ctx.new_val) {
1716 			memcpy(ctx.new_val, *buf, ctx.new_len);
1717 		} else {
1718 			/* Let BPF program decide how to proceed. */
1719 			ctx.new_len = 0;
1720 		}
1721 	}
1722 
1723 	rcu_read_lock();
1724 	cgrp = task_dfl_cgroup(current);
1725 	ret = bpf_prog_run_array_cg(&cgrp->bpf, atype, &ctx, bpf_prog_run, 0,
1726 				    NULL);
1727 	rcu_read_unlock();
1728 
1729 	kfree(ctx.cur_val);
1730 
1731 	if (ret == 1 && ctx.new_updated) {
1732 		kfree(*buf);
1733 		*buf = ctx.new_val;
1734 		*pcount = ctx.new_len;
1735 	} else {
1736 		kfree(ctx.new_val);
1737 	}
1738 
1739 	return ret;
1740 }
1741 
1742 #ifdef CONFIG_NET
1743 static int sockopt_alloc_buf(struct bpf_sockopt_kern *ctx, int max_optlen,
1744 			     struct bpf_sockopt_buf *buf)
1745 {
1746 	if (unlikely(max_optlen < 0))
1747 		return -EINVAL;
1748 
1749 	if (unlikely(max_optlen > PAGE_SIZE)) {
1750 		/* We don't expose optvals that are greater than PAGE_SIZE
1751 		 * to the BPF program.
1752 		 */
1753 		max_optlen = PAGE_SIZE;
1754 	}
1755 
1756 	if (max_optlen <= sizeof(buf->data)) {
1757 		/* When the optval fits into BPF_SOCKOPT_KERN_BUF_SIZE
1758 		 * bytes avoid the cost of kzalloc.
1759 		 */
1760 		ctx->optval = buf->data;
1761 		ctx->optval_end = ctx->optval + max_optlen;
1762 		return max_optlen;
1763 	}
1764 
1765 	ctx->optval = kzalloc(max_optlen, GFP_USER);
1766 	if (!ctx->optval)
1767 		return -ENOMEM;
1768 
1769 	ctx->optval_end = ctx->optval + max_optlen;
1770 
1771 	return max_optlen;
1772 }
1773 
1774 static void sockopt_free_buf(struct bpf_sockopt_kern *ctx,
1775 			     struct bpf_sockopt_buf *buf)
1776 {
1777 	if (ctx->optval == buf->data)
1778 		return;
1779 	kfree(ctx->optval);
1780 }
1781 
1782 static bool sockopt_buf_allocated(struct bpf_sockopt_kern *ctx,
1783 				  struct bpf_sockopt_buf *buf)
1784 {
1785 	return ctx->optval != buf->data;
1786 }
1787 
1788 int __cgroup_bpf_run_filter_setsockopt(struct sock *sk, int *level,
1789 				       int *optname, char __user *optval,
1790 				       int *optlen, char **kernel_optval)
1791 {
1792 	struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
1793 	struct bpf_sockopt_buf buf = {};
1794 	struct bpf_sockopt_kern ctx = {
1795 		.sk = sk,
1796 		.level = *level,
1797 		.optname = *optname,
1798 	};
1799 	int ret, max_optlen;
1800 
1801 	/* Allocate a bit more than the initial user buffer for
1802 	 * BPF program. The canonical use case is overriding
1803 	 * TCP_CONGESTION(nv) to TCP_CONGESTION(cubic).
1804 	 */
1805 	max_optlen = max_t(int, 16, *optlen);
1806 	max_optlen = sockopt_alloc_buf(&ctx, max_optlen, &buf);
1807 	if (max_optlen < 0)
1808 		return max_optlen;
1809 
1810 	ctx.optlen = *optlen;
1811 
1812 	if (copy_from_user(ctx.optval, optval, min(*optlen, max_optlen)) != 0) {
1813 		ret = -EFAULT;
1814 		goto out;
1815 	}
1816 
1817 	lock_sock(sk);
1818 	ret = bpf_prog_run_array_cg(&cgrp->bpf, CGROUP_SETSOCKOPT,
1819 				    &ctx, bpf_prog_run, 0, NULL);
1820 	release_sock(sk);
1821 
1822 	if (ret)
1823 		goto out;
1824 
1825 	if (ctx.optlen == -1) {
1826 		/* optlen set to -1, bypass kernel */
1827 		ret = 1;
1828 	} else if (ctx.optlen > max_optlen || ctx.optlen < -1) {
1829 		/* optlen is out of bounds */
1830 		if (*optlen > PAGE_SIZE && ctx.optlen >= 0) {
1831 			pr_info_once("bpf setsockopt: ignoring program buffer with optlen=%d (max_optlen=%d)\n",
1832 				     ctx.optlen, max_optlen);
1833 			ret = 0;
1834 			goto out;
1835 		}
1836 		ret = -EFAULT;
1837 	} else {
1838 		/* optlen within bounds, run kernel handler */
1839 		ret = 0;
1840 
1841 		/* export any potential modifications */
1842 		*level = ctx.level;
1843 		*optname = ctx.optname;
1844 
1845 		/* optlen == 0 from BPF indicates that we should
1846 		 * use original userspace data.
1847 		 */
1848 		if (ctx.optlen != 0) {
1849 			*optlen = ctx.optlen;
1850 			/* We've used bpf_sockopt_kern->buf as an intermediary
1851 			 * storage, but the BPF program indicates that we need
1852 			 * to pass this data to the kernel setsockopt handler.
1853 			 * No way to export on-stack buf, have to allocate a
1854 			 * new buffer.
1855 			 */
1856 			if (!sockopt_buf_allocated(&ctx, &buf)) {
1857 				void *p = kmalloc(ctx.optlen, GFP_USER);
1858 
1859 				if (!p) {
1860 					ret = -ENOMEM;
1861 					goto out;
1862 				}
1863 				memcpy(p, ctx.optval, ctx.optlen);
1864 				*kernel_optval = p;
1865 			} else {
1866 				*kernel_optval = ctx.optval;
1867 			}
1868 			/* export and don't free sockopt buf */
1869 			return 0;
1870 		}
1871 	}
1872 
1873 out:
1874 	sockopt_free_buf(&ctx, &buf);
1875 	return ret;
1876 }
1877 
1878 int __cgroup_bpf_run_filter_getsockopt(struct sock *sk, int level,
1879 				       int optname, char __user *optval,
1880 				       int __user *optlen, int max_optlen,
1881 				       int retval)
1882 {
1883 	struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
1884 	struct bpf_sockopt_buf buf = {};
1885 	struct bpf_sockopt_kern ctx = {
1886 		.sk = sk,
1887 		.level = level,
1888 		.optname = optname,
1889 		.current_task = current,
1890 	};
1891 	int orig_optlen;
1892 	int ret;
1893 
1894 	orig_optlen = max_optlen;
1895 	ctx.optlen = max_optlen;
1896 	max_optlen = sockopt_alloc_buf(&ctx, max_optlen, &buf);
1897 	if (max_optlen < 0)
1898 		return max_optlen;
1899 
1900 	if (!retval) {
1901 		/* If kernel getsockopt finished successfully,
1902 		 * copy whatever was returned to the user back
1903 		 * into our temporary buffer. Set optlen to the
1904 		 * one that kernel returned as well to let
1905 		 * BPF programs inspect the value.
1906 		 */
1907 
1908 		if (get_user(ctx.optlen, optlen)) {
1909 			ret = -EFAULT;
1910 			goto out;
1911 		}
1912 
1913 		if (ctx.optlen < 0) {
1914 			ret = -EFAULT;
1915 			goto out;
1916 		}
1917 		orig_optlen = ctx.optlen;
1918 
1919 		if (copy_from_user(ctx.optval, optval,
1920 				   min(ctx.optlen, max_optlen)) != 0) {
1921 			ret = -EFAULT;
1922 			goto out;
1923 		}
1924 	}
1925 
1926 	lock_sock(sk);
1927 	ret = bpf_prog_run_array_cg(&cgrp->bpf, CGROUP_GETSOCKOPT,
1928 				    &ctx, bpf_prog_run, retval, NULL);
1929 	release_sock(sk);
1930 
1931 	if (ret < 0)
1932 		goto out;
1933 
1934 	if (optval && (ctx.optlen > max_optlen || ctx.optlen < 0)) {
1935 		if (orig_optlen > PAGE_SIZE && ctx.optlen >= 0) {
1936 			pr_info_once("bpf getsockopt: ignoring program buffer with optlen=%d (max_optlen=%d)\n",
1937 				     ctx.optlen, max_optlen);
1938 			ret = retval;
1939 			goto out;
1940 		}
1941 		ret = -EFAULT;
1942 		goto out;
1943 	}
1944 
1945 	if (ctx.optlen != 0) {
1946 		if (optval && copy_to_user(optval, ctx.optval, ctx.optlen)) {
1947 			ret = -EFAULT;
1948 			goto out;
1949 		}
1950 		if (put_user(ctx.optlen, optlen)) {
1951 			ret = -EFAULT;
1952 			goto out;
1953 		}
1954 	}
1955 
1956 out:
1957 	sockopt_free_buf(&ctx, &buf);
1958 	return ret;
1959 }
1960 
1961 int __cgroup_bpf_run_filter_getsockopt_kern(struct sock *sk, int level,
1962 					    int optname, void *optval,
1963 					    int *optlen, int retval)
1964 {
1965 	struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
1966 	struct bpf_sockopt_kern ctx = {
1967 		.sk = sk,
1968 		.level = level,
1969 		.optname = optname,
1970 		.optlen = *optlen,
1971 		.optval = optval,
1972 		.optval_end = optval + *optlen,
1973 		.current_task = current,
1974 	};
1975 	int ret;
1976 
1977 	/* Note that __cgroup_bpf_run_filter_getsockopt doesn't copy
1978 	 * user data back into BPF buffer when reval != 0. This is
1979 	 * done as an optimization to avoid extra copy, assuming
1980 	 * kernel won't populate the data in case of an error.
1981 	 * Here we always pass the data and memset() should
1982 	 * be called if that data shouldn't be "exported".
1983 	 */
1984 
1985 	ret = bpf_prog_run_array_cg(&cgrp->bpf, CGROUP_GETSOCKOPT,
1986 				    &ctx, bpf_prog_run, retval, NULL);
1987 	if (ret < 0)
1988 		return ret;
1989 
1990 	if (ctx.optlen > *optlen)
1991 		return -EFAULT;
1992 
1993 	/* BPF programs can shrink the buffer, export the modifications.
1994 	 */
1995 	if (ctx.optlen != 0)
1996 		*optlen = ctx.optlen;
1997 
1998 	return ret;
1999 }
2000 #endif
2001 
2002 static ssize_t sysctl_cpy_dir(const struct ctl_dir *dir, char **bufp,
2003 			      size_t *lenp)
2004 {
2005 	ssize_t tmp_ret = 0, ret;
2006 
2007 	if (dir->header.parent) {
2008 		tmp_ret = sysctl_cpy_dir(dir->header.parent, bufp, lenp);
2009 		if (tmp_ret < 0)
2010 			return tmp_ret;
2011 	}
2012 
2013 	ret = strscpy(*bufp, dir->header.ctl_table[0].procname, *lenp);
2014 	if (ret < 0)
2015 		return ret;
2016 	*bufp += ret;
2017 	*lenp -= ret;
2018 	ret += tmp_ret;
2019 
2020 	/* Avoid leading slash. */
2021 	if (!ret)
2022 		return ret;
2023 
2024 	tmp_ret = strscpy(*bufp, "/", *lenp);
2025 	if (tmp_ret < 0)
2026 		return tmp_ret;
2027 	*bufp += tmp_ret;
2028 	*lenp -= tmp_ret;
2029 
2030 	return ret + tmp_ret;
2031 }
2032 
2033 BPF_CALL_4(bpf_sysctl_get_name, struct bpf_sysctl_kern *, ctx, char *, buf,
2034 	   size_t, buf_len, u64, flags)
2035 {
2036 	ssize_t tmp_ret = 0, ret;
2037 
2038 	if (!buf)
2039 		return -EINVAL;
2040 
2041 	if (!(flags & BPF_F_SYSCTL_BASE_NAME)) {
2042 		if (!ctx->head)
2043 			return -EINVAL;
2044 		tmp_ret = sysctl_cpy_dir(ctx->head->parent, &buf, &buf_len);
2045 		if (tmp_ret < 0)
2046 			return tmp_ret;
2047 	}
2048 
2049 	ret = strscpy(buf, ctx->table->procname, buf_len);
2050 
2051 	return ret < 0 ? ret : tmp_ret + ret;
2052 }
2053 
2054 static const struct bpf_func_proto bpf_sysctl_get_name_proto = {
2055 	.func		= bpf_sysctl_get_name,
2056 	.gpl_only	= false,
2057 	.ret_type	= RET_INTEGER,
2058 	.arg1_type	= ARG_PTR_TO_CTX,
2059 	.arg2_type	= ARG_PTR_TO_MEM,
2060 	.arg3_type	= ARG_CONST_SIZE,
2061 	.arg4_type	= ARG_ANYTHING,
2062 };
2063 
2064 static int copy_sysctl_value(char *dst, size_t dst_len, char *src,
2065 			     size_t src_len)
2066 {
2067 	if (!dst)
2068 		return -EINVAL;
2069 
2070 	if (!dst_len)
2071 		return -E2BIG;
2072 
2073 	if (!src || !src_len) {
2074 		memset(dst, 0, dst_len);
2075 		return -EINVAL;
2076 	}
2077 
2078 	memcpy(dst, src, min(dst_len, src_len));
2079 
2080 	if (dst_len > src_len) {
2081 		memset(dst + src_len, '\0', dst_len - src_len);
2082 		return src_len;
2083 	}
2084 
2085 	dst[dst_len - 1] = '\0';
2086 
2087 	return -E2BIG;
2088 }
2089 
2090 BPF_CALL_3(bpf_sysctl_get_current_value, struct bpf_sysctl_kern *, ctx,
2091 	   char *, buf, size_t, buf_len)
2092 {
2093 	return copy_sysctl_value(buf, buf_len, ctx->cur_val, ctx->cur_len);
2094 }
2095 
2096 static const struct bpf_func_proto bpf_sysctl_get_current_value_proto = {
2097 	.func		= bpf_sysctl_get_current_value,
2098 	.gpl_only	= false,
2099 	.ret_type	= RET_INTEGER,
2100 	.arg1_type	= ARG_PTR_TO_CTX,
2101 	.arg2_type	= ARG_PTR_TO_UNINIT_MEM,
2102 	.arg3_type	= ARG_CONST_SIZE,
2103 };
2104 
2105 BPF_CALL_3(bpf_sysctl_get_new_value, struct bpf_sysctl_kern *, ctx, char *, buf,
2106 	   size_t, buf_len)
2107 {
2108 	if (!ctx->write) {
2109 		if (buf && buf_len)
2110 			memset(buf, '\0', buf_len);
2111 		return -EINVAL;
2112 	}
2113 	return copy_sysctl_value(buf, buf_len, ctx->new_val, ctx->new_len);
2114 }
2115 
2116 static const struct bpf_func_proto bpf_sysctl_get_new_value_proto = {
2117 	.func		= bpf_sysctl_get_new_value,
2118 	.gpl_only	= false,
2119 	.ret_type	= RET_INTEGER,
2120 	.arg1_type	= ARG_PTR_TO_CTX,
2121 	.arg2_type	= ARG_PTR_TO_UNINIT_MEM,
2122 	.arg3_type	= ARG_CONST_SIZE,
2123 };
2124 
2125 BPF_CALL_3(bpf_sysctl_set_new_value, struct bpf_sysctl_kern *, ctx,
2126 	   const char *, buf, size_t, buf_len)
2127 {
2128 	if (!ctx->write || !ctx->new_val || !ctx->new_len || !buf || !buf_len)
2129 		return -EINVAL;
2130 
2131 	if (buf_len > PAGE_SIZE - 1)
2132 		return -E2BIG;
2133 
2134 	memcpy(ctx->new_val, buf, buf_len);
2135 	ctx->new_len = buf_len;
2136 	ctx->new_updated = 1;
2137 
2138 	return 0;
2139 }
2140 
2141 static const struct bpf_func_proto bpf_sysctl_set_new_value_proto = {
2142 	.func		= bpf_sysctl_set_new_value,
2143 	.gpl_only	= false,
2144 	.ret_type	= RET_INTEGER,
2145 	.arg1_type	= ARG_PTR_TO_CTX,
2146 	.arg2_type	= ARG_PTR_TO_MEM | MEM_RDONLY,
2147 	.arg3_type	= ARG_CONST_SIZE,
2148 };
2149 
2150 static const struct bpf_func_proto *
2151 sysctl_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
2152 {
2153 	const struct bpf_func_proto *func_proto;
2154 
2155 	func_proto = cgroup_common_func_proto(func_id, prog);
2156 	if (func_proto)
2157 		return func_proto;
2158 
2159 	func_proto = cgroup_current_func_proto(func_id, prog);
2160 	if (func_proto)
2161 		return func_proto;
2162 
2163 	switch (func_id) {
2164 	case BPF_FUNC_sysctl_get_name:
2165 		return &bpf_sysctl_get_name_proto;
2166 	case BPF_FUNC_sysctl_get_current_value:
2167 		return &bpf_sysctl_get_current_value_proto;
2168 	case BPF_FUNC_sysctl_get_new_value:
2169 		return &bpf_sysctl_get_new_value_proto;
2170 	case BPF_FUNC_sysctl_set_new_value:
2171 		return &bpf_sysctl_set_new_value_proto;
2172 	case BPF_FUNC_ktime_get_coarse_ns:
2173 		return &bpf_ktime_get_coarse_ns_proto;
2174 	case BPF_FUNC_perf_event_output:
2175 		return &bpf_event_output_data_proto;
2176 	default:
2177 		return bpf_base_func_proto(func_id);
2178 	}
2179 }
2180 
2181 static bool sysctl_is_valid_access(int off, int size, enum bpf_access_type type,
2182 				   const struct bpf_prog *prog,
2183 				   struct bpf_insn_access_aux *info)
2184 {
2185 	const int size_default = sizeof(__u32);
2186 
2187 	if (off < 0 || off + size > sizeof(struct bpf_sysctl) || off % size)
2188 		return false;
2189 
2190 	switch (off) {
2191 	case bpf_ctx_range(struct bpf_sysctl, write):
2192 		if (type != BPF_READ)
2193 			return false;
2194 		bpf_ctx_record_field_size(info, size_default);
2195 		return bpf_ctx_narrow_access_ok(off, size, size_default);
2196 	case bpf_ctx_range(struct bpf_sysctl, file_pos):
2197 		if (type == BPF_READ) {
2198 			bpf_ctx_record_field_size(info, size_default);
2199 			return bpf_ctx_narrow_access_ok(off, size, size_default);
2200 		} else {
2201 			return size == size_default;
2202 		}
2203 	default:
2204 		return false;
2205 	}
2206 }
2207 
2208 static u32 sysctl_convert_ctx_access(enum bpf_access_type type,
2209 				     const struct bpf_insn *si,
2210 				     struct bpf_insn *insn_buf,
2211 				     struct bpf_prog *prog, u32 *target_size)
2212 {
2213 	struct bpf_insn *insn = insn_buf;
2214 	u32 read_size;
2215 
2216 	switch (si->off) {
2217 	case offsetof(struct bpf_sysctl, write):
2218 		*insn++ = BPF_LDX_MEM(
2219 			BPF_SIZE(si->code), si->dst_reg, si->src_reg,
2220 			bpf_target_off(struct bpf_sysctl_kern, write,
2221 				       sizeof_field(struct bpf_sysctl_kern,
2222 						    write),
2223 				       target_size));
2224 		break;
2225 	case offsetof(struct bpf_sysctl, file_pos):
2226 		/* ppos is a pointer so it should be accessed via indirect
2227 		 * loads and stores. Also for stores additional temporary
2228 		 * register is used since neither src_reg nor dst_reg can be
2229 		 * overridden.
2230 		 */
2231 		if (type == BPF_WRITE) {
2232 			int treg = BPF_REG_9;
2233 
2234 			if (si->src_reg == treg || si->dst_reg == treg)
2235 				--treg;
2236 			if (si->src_reg == treg || si->dst_reg == treg)
2237 				--treg;
2238 			*insn++ = BPF_STX_MEM(
2239 				BPF_DW, si->dst_reg, treg,
2240 				offsetof(struct bpf_sysctl_kern, tmp_reg));
2241 			*insn++ = BPF_LDX_MEM(
2242 				BPF_FIELD_SIZEOF(struct bpf_sysctl_kern, ppos),
2243 				treg, si->dst_reg,
2244 				offsetof(struct bpf_sysctl_kern, ppos));
2245 			*insn++ = BPF_RAW_INSN(
2246 				BPF_CLASS(si->code) | BPF_MEM | BPF_SIZEOF(u32),
2247 				treg, si->src_reg,
2248 				bpf_ctx_narrow_access_offset(
2249 					0, sizeof(u32), sizeof(loff_t)),
2250 				si->imm);
2251 			*insn++ = BPF_LDX_MEM(
2252 				BPF_DW, treg, si->dst_reg,
2253 				offsetof(struct bpf_sysctl_kern, tmp_reg));
2254 		} else {
2255 			*insn++ = BPF_LDX_MEM(
2256 				BPF_FIELD_SIZEOF(struct bpf_sysctl_kern, ppos),
2257 				si->dst_reg, si->src_reg,
2258 				offsetof(struct bpf_sysctl_kern, ppos));
2259 			read_size = bpf_size_to_bytes(BPF_SIZE(si->code));
2260 			*insn++ = BPF_LDX_MEM(
2261 				BPF_SIZE(si->code), si->dst_reg, si->dst_reg,
2262 				bpf_ctx_narrow_access_offset(
2263 					0, read_size, sizeof(loff_t)));
2264 		}
2265 		*target_size = sizeof(u32);
2266 		break;
2267 	}
2268 
2269 	return insn - insn_buf;
2270 }
2271 
2272 const struct bpf_verifier_ops cg_sysctl_verifier_ops = {
2273 	.get_func_proto		= sysctl_func_proto,
2274 	.is_valid_access	= sysctl_is_valid_access,
2275 	.convert_ctx_access	= sysctl_convert_ctx_access,
2276 };
2277 
2278 const struct bpf_prog_ops cg_sysctl_prog_ops = {
2279 };
2280 
2281 #ifdef CONFIG_NET
2282 BPF_CALL_1(bpf_get_netns_cookie_sockopt, struct bpf_sockopt_kern *, ctx)
2283 {
2284 	const struct net *net = ctx ? sock_net(ctx->sk) : &init_net;
2285 
2286 	return net->net_cookie;
2287 }
2288 
2289 static const struct bpf_func_proto bpf_get_netns_cookie_sockopt_proto = {
2290 	.func		= bpf_get_netns_cookie_sockopt,
2291 	.gpl_only	= false,
2292 	.ret_type	= RET_INTEGER,
2293 	.arg1_type	= ARG_PTR_TO_CTX_OR_NULL,
2294 };
2295 #endif
2296 
2297 static const struct bpf_func_proto *
2298 cg_sockopt_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
2299 {
2300 	const struct bpf_func_proto *func_proto;
2301 
2302 	func_proto = cgroup_common_func_proto(func_id, prog);
2303 	if (func_proto)
2304 		return func_proto;
2305 
2306 	func_proto = cgroup_current_func_proto(func_id, prog);
2307 	if (func_proto)
2308 		return func_proto;
2309 
2310 	switch (func_id) {
2311 #ifdef CONFIG_NET
2312 	case BPF_FUNC_get_netns_cookie:
2313 		return &bpf_get_netns_cookie_sockopt_proto;
2314 	case BPF_FUNC_sk_storage_get:
2315 		return &bpf_sk_storage_get_proto;
2316 	case BPF_FUNC_sk_storage_delete:
2317 		return &bpf_sk_storage_delete_proto;
2318 	case BPF_FUNC_setsockopt:
2319 		if (prog->expected_attach_type == BPF_CGROUP_SETSOCKOPT)
2320 			return &bpf_sk_setsockopt_proto;
2321 		return NULL;
2322 	case BPF_FUNC_getsockopt:
2323 		if (prog->expected_attach_type == BPF_CGROUP_SETSOCKOPT)
2324 			return &bpf_sk_getsockopt_proto;
2325 		return NULL;
2326 #endif
2327 #ifdef CONFIG_INET
2328 	case BPF_FUNC_tcp_sock:
2329 		return &bpf_tcp_sock_proto;
2330 #endif
2331 	case BPF_FUNC_perf_event_output:
2332 		return &bpf_event_output_data_proto;
2333 	default:
2334 		return bpf_base_func_proto(func_id);
2335 	}
2336 }
2337 
2338 static bool cg_sockopt_is_valid_access(int off, int size,
2339 				       enum bpf_access_type type,
2340 				       const struct bpf_prog *prog,
2341 				       struct bpf_insn_access_aux *info)
2342 {
2343 	const int size_default = sizeof(__u32);
2344 
2345 	if (off < 0 || off >= sizeof(struct bpf_sockopt))
2346 		return false;
2347 
2348 	if (off % size != 0)
2349 		return false;
2350 
2351 	if (type == BPF_WRITE) {
2352 		switch (off) {
2353 		case offsetof(struct bpf_sockopt, retval):
2354 			if (size != size_default)
2355 				return false;
2356 			return prog->expected_attach_type ==
2357 				BPF_CGROUP_GETSOCKOPT;
2358 		case offsetof(struct bpf_sockopt, optname):
2359 			fallthrough;
2360 		case offsetof(struct bpf_sockopt, level):
2361 			if (size != size_default)
2362 				return false;
2363 			return prog->expected_attach_type ==
2364 				BPF_CGROUP_SETSOCKOPT;
2365 		case offsetof(struct bpf_sockopt, optlen):
2366 			return size == size_default;
2367 		default:
2368 			return false;
2369 		}
2370 	}
2371 
2372 	switch (off) {
2373 	case offsetof(struct bpf_sockopt, sk):
2374 		if (size != sizeof(__u64))
2375 			return false;
2376 		info->reg_type = PTR_TO_SOCKET;
2377 		break;
2378 	case offsetof(struct bpf_sockopt, optval):
2379 		if (size != sizeof(__u64))
2380 			return false;
2381 		info->reg_type = PTR_TO_PACKET;
2382 		break;
2383 	case offsetof(struct bpf_sockopt, optval_end):
2384 		if (size != sizeof(__u64))
2385 			return false;
2386 		info->reg_type = PTR_TO_PACKET_END;
2387 		break;
2388 	case offsetof(struct bpf_sockopt, retval):
2389 		if (size != size_default)
2390 			return false;
2391 		return prog->expected_attach_type == BPF_CGROUP_GETSOCKOPT;
2392 	default:
2393 		if (size != size_default)
2394 			return false;
2395 		break;
2396 	}
2397 	return true;
2398 }
2399 
2400 #define CG_SOCKOPT_READ_FIELD(F)					\
2401 	BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_sockopt_kern, F),	\
2402 		    si->dst_reg, si->src_reg,				\
2403 		    offsetof(struct bpf_sockopt_kern, F))
2404 
2405 #define CG_SOCKOPT_WRITE_FIELD(F)					\
2406 	BPF_RAW_INSN((BPF_FIELD_SIZEOF(struct bpf_sockopt_kern, F) |	\
2407 		      BPF_MEM | BPF_CLASS(si->code)),			\
2408 		     si->dst_reg, si->src_reg,				\
2409 		     offsetof(struct bpf_sockopt_kern, F),		\
2410 		     si->imm)
2411 
2412 static u32 cg_sockopt_convert_ctx_access(enum bpf_access_type type,
2413 					 const struct bpf_insn *si,
2414 					 struct bpf_insn *insn_buf,
2415 					 struct bpf_prog *prog,
2416 					 u32 *target_size)
2417 {
2418 	struct bpf_insn *insn = insn_buf;
2419 
2420 	switch (si->off) {
2421 	case offsetof(struct bpf_sockopt, sk):
2422 		*insn++ = CG_SOCKOPT_READ_FIELD(sk);
2423 		break;
2424 	case offsetof(struct bpf_sockopt, level):
2425 		if (type == BPF_WRITE)
2426 			*insn++ = CG_SOCKOPT_WRITE_FIELD(level);
2427 		else
2428 			*insn++ = CG_SOCKOPT_READ_FIELD(level);
2429 		break;
2430 	case offsetof(struct bpf_sockopt, optname):
2431 		if (type == BPF_WRITE)
2432 			*insn++ = CG_SOCKOPT_WRITE_FIELD(optname);
2433 		else
2434 			*insn++ = CG_SOCKOPT_READ_FIELD(optname);
2435 		break;
2436 	case offsetof(struct bpf_sockopt, optlen):
2437 		if (type == BPF_WRITE)
2438 			*insn++ = CG_SOCKOPT_WRITE_FIELD(optlen);
2439 		else
2440 			*insn++ = CG_SOCKOPT_READ_FIELD(optlen);
2441 		break;
2442 	case offsetof(struct bpf_sockopt, retval):
2443 		BUILD_BUG_ON(offsetof(struct bpf_cg_run_ctx, run_ctx) != 0);
2444 
2445 		if (type == BPF_WRITE) {
2446 			int treg = BPF_REG_9;
2447 
2448 			if (si->src_reg == treg || si->dst_reg == treg)
2449 				--treg;
2450 			if (si->src_reg == treg || si->dst_reg == treg)
2451 				--treg;
2452 			*insn++ = BPF_STX_MEM(BPF_DW, si->dst_reg, treg,
2453 					      offsetof(struct bpf_sockopt_kern, tmp_reg));
2454 			*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_sockopt_kern, current_task),
2455 					      treg, si->dst_reg,
2456 					      offsetof(struct bpf_sockopt_kern, current_task));
2457 			*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct task_struct, bpf_ctx),
2458 					      treg, treg,
2459 					      offsetof(struct task_struct, bpf_ctx));
2460 			*insn++ = BPF_RAW_INSN(BPF_CLASS(si->code) | BPF_MEM |
2461 					       BPF_FIELD_SIZEOF(struct bpf_cg_run_ctx, retval),
2462 					       treg, si->src_reg,
2463 					       offsetof(struct bpf_cg_run_ctx, retval),
2464 					       si->imm);
2465 			*insn++ = BPF_LDX_MEM(BPF_DW, treg, si->dst_reg,
2466 					      offsetof(struct bpf_sockopt_kern, tmp_reg));
2467 		} else {
2468 			*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_sockopt_kern, current_task),
2469 					      si->dst_reg, si->src_reg,
2470 					      offsetof(struct bpf_sockopt_kern, current_task));
2471 			*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct task_struct, bpf_ctx),
2472 					      si->dst_reg, si->dst_reg,
2473 					      offsetof(struct task_struct, bpf_ctx));
2474 			*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_cg_run_ctx, retval),
2475 					      si->dst_reg, si->dst_reg,
2476 					      offsetof(struct bpf_cg_run_ctx, retval));
2477 		}
2478 		break;
2479 	case offsetof(struct bpf_sockopt, optval):
2480 		*insn++ = CG_SOCKOPT_READ_FIELD(optval);
2481 		break;
2482 	case offsetof(struct bpf_sockopt, optval_end):
2483 		*insn++ = CG_SOCKOPT_READ_FIELD(optval_end);
2484 		break;
2485 	}
2486 
2487 	return insn - insn_buf;
2488 }
2489 
2490 static int cg_sockopt_get_prologue(struct bpf_insn *insn_buf,
2491 				   bool direct_write,
2492 				   const struct bpf_prog *prog)
2493 {
2494 	/* Nothing to do for sockopt argument. The data is kzalloc'ated.
2495 	 */
2496 	return 0;
2497 }
2498 
2499 const struct bpf_verifier_ops cg_sockopt_verifier_ops = {
2500 	.get_func_proto		= cg_sockopt_func_proto,
2501 	.is_valid_access	= cg_sockopt_is_valid_access,
2502 	.convert_ctx_access	= cg_sockopt_convert_ctx_access,
2503 	.gen_prologue		= cg_sockopt_get_prologue,
2504 };
2505 
2506 const struct bpf_prog_ops cg_sockopt_prog_ops = {
2507 };
2508 
2509 /* Common helpers for cgroup hooks. */
2510 const struct bpf_func_proto *
2511 cgroup_common_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
2512 {
2513 	switch (func_id) {
2514 	case BPF_FUNC_get_local_storage:
2515 		return &bpf_get_local_storage_proto;
2516 	case BPF_FUNC_get_retval:
2517 		switch (prog->expected_attach_type) {
2518 		case BPF_CGROUP_INET_INGRESS:
2519 		case BPF_CGROUP_INET_EGRESS:
2520 		case BPF_CGROUP_SOCK_OPS:
2521 		case BPF_CGROUP_UDP4_RECVMSG:
2522 		case BPF_CGROUP_UDP6_RECVMSG:
2523 		case BPF_CGROUP_INET4_GETPEERNAME:
2524 		case BPF_CGROUP_INET6_GETPEERNAME:
2525 		case BPF_CGROUP_INET4_GETSOCKNAME:
2526 		case BPF_CGROUP_INET6_GETSOCKNAME:
2527 			return NULL;
2528 		default:
2529 			return &bpf_get_retval_proto;
2530 		}
2531 	case BPF_FUNC_set_retval:
2532 		switch (prog->expected_attach_type) {
2533 		case BPF_CGROUP_INET_INGRESS:
2534 		case BPF_CGROUP_INET_EGRESS:
2535 		case BPF_CGROUP_SOCK_OPS:
2536 		case BPF_CGROUP_UDP4_RECVMSG:
2537 		case BPF_CGROUP_UDP6_RECVMSG:
2538 		case BPF_CGROUP_INET4_GETPEERNAME:
2539 		case BPF_CGROUP_INET6_GETPEERNAME:
2540 		case BPF_CGROUP_INET4_GETSOCKNAME:
2541 		case BPF_CGROUP_INET6_GETSOCKNAME:
2542 			return NULL;
2543 		default:
2544 			return &bpf_set_retval_proto;
2545 		}
2546 	default:
2547 		return NULL;
2548 	}
2549 }
2550 
2551 /* Common helpers for cgroup hooks with valid process context. */
2552 const struct bpf_func_proto *
2553 cgroup_current_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
2554 {
2555 	switch (func_id) {
2556 	case BPF_FUNC_get_current_uid_gid:
2557 		return &bpf_get_current_uid_gid_proto;
2558 	case BPF_FUNC_get_current_pid_tgid:
2559 		return &bpf_get_current_pid_tgid_proto;
2560 	case BPF_FUNC_get_current_comm:
2561 		return &bpf_get_current_comm_proto;
2562 #ifdef CONFIG_CGROUP_NET_CLASSID
2563 	case BPF_FUNC_get_cgroup_classid:
2564 		return &bpf_get_cgroup_classid_curr_proto;
2565 #endif
2566 	default:
2567 		return NULL;
2568 	}
2569 }
2570