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 24DEFINE_STATIC_KEY_ARRAY_FALSE(cgroup_bpf_enabled_key, MAX_CGROUP_BPF_ATTACH_TYPE); 25EXPORT_SYMBOL(cgroup_bpf_enabled_key); 26 27/* __always_inline is necessary to prevent indirect call through run_prog 28 * function pointer. 29 */ 30static __always_inline int 31bpf_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 66unsigned 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 88unsigned 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 110unsigned 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 130struct cgroup_lsm_atype { 131 u32 attach_btf_id; 132 int refcnt; 133}; 134 135static struct cgroup_lsm_atype cgroup_lsm_atype[CGROUP_LSM_NUM]; 136 137static enum cgroup_bpf_attach_type 138bpf_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 159void 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 172void 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 183static enum cgroup_bpf_attach_type 184bpf_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 192void cgroup_bpf_offline(struct cgroup *cgrp) 193{ 194 cgroup_get(cgrp); 195 percpu_ref_kill(&cgrp->bpf.refcnt); 196} 197 198static 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 206static 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 240static 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 249static 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 */ 264static 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 */ 275static 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 */ 332static 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 */ 343static 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 */ 355static 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 */ 372static 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 */ 401static 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 445static 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 */ 461int 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; 492cleanup: 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 504static 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 540cleanup: 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 556static 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 */ 607static 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 707cleanup_trampoline: 708 if (type == BPF_LSM_CGROUP) 709 bpf_trampoline_unlink_cgroup_shim(new_prog); 710 711cleanup: 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 724static 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 */ 741static 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 } 773found: 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 */ 793static 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 827static 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); 846out_unlock: 847 cgroup_unlock(); 848 return ret; 849} 850 851static 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 */ 893static 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; 928found: 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 */ 950static 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 1008static 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. */ 1020static 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 1119static 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 1130int 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 1159int 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 1181static 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 1214static 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 1222static int bpf_cgroup_link_detach(struct bpf_link *link) 1223{ 1224 bpf_cgroup_link_release(link); 1225 1226 return 0; 1227} 1228 1229static 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 1248static 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 1265static 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 1274int 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 1313out_put_cgroup: 1314 cgroup_put(cgrp); 1315 return err; 1316} 1317 1318int 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 */ 1357int __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_network_offset(skb); 1362 struct sock *save_sk; 1363 void *saved_data_end; 1364 struct cgroup *cgrp; 1365 int ret; 1366 1367 if (sk->sk_family != AF_INET && sk->sk_family != AF_INET6) 1368 return 0; 1369 1370 cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data); 1371 save_sk = skb->sk; 1372 skb->sk = sk; 1373 __skb_push(skb, offset); 1374 1375 /* compute pointers for the bpf prog */ 1376 bpf_compute_and_save_data_end(skb, &saved_data_end); 1377 1378 if (atype == CGROUP_INET_EGRESS) { 1379 u32 flags = 0; 1380 bool cn; 1381 1382 ret = bpf_prog_run_array_cg(&cgrp->bpf, atype, skb, 1383 __bpf_prog_run_save_cb, 0, &flags); 1384 1385 /* Return values of CGROUP EGRESS BPF programs are: 1386 * 0: drop packet 1387 * 1: keep packet 1388 * 2: drop packet and cn 1389 * 3: keep packet and cn 1390 * 1391 * The returned value is then converted to one of the NET_XMIT 1392 * or an error code that is then interpreted as drop packet 1393 * (and no cn): 1394 * 0: NET_XMIT_SUCCESS skb should be transmitted 1395 * 1: NET_XMIT_DROP skb should be dropped and cn 1396 * 2: NET_XMIT_CN skb should be transmitted and cn 1397 * 3: -err skb should be dropped 1398 */ 1399 1400 cn = flags & BPF_RET_SET_CN; 1401 if (ret && !IS_ERR_VALUE((long)ret)) 1402 ret = -EFAULT; 1403 if (!ret) 1404 ret = (cn ? NET_XMIT_CN : NET_XMIT_SUCCESS); 1405 else 1406 ret = (cn ? NET_XMIT_DROP : ret); 1407 } else { 1408 ret = bpf_prog_run_array_cg(&cgrp->bpf, atype, 1409 skb, __bpf_prog_run_save_cb, 0, 1410 NULL); 1411 if (ret && !IS_ERR_VALUE((long)ret)) 1412 ret = -EFAULT; 1413 } 1414 bpf_restore_data_end(skb, saved_data_end); 1415 __skb_pull(skb, offset); 1416 skb->sk = save_sk; 1417 1418 return ret; 1419} 1420EXPORT_SYMBOL(__cgroup_bpf_run_filter_skb); 1421 1422/** 1423 * __cgroup_bpf_run_filter_sk() - Run a program on a sock 1424 * @sk: sock structure to manipulate 1425 * @atype: The type of program to be executed 1426 * 1427 * socket is passed is expected to be of type INET or INET6. 1428 * 1429 * The program type passed in via @type must be suitable for sock 1430 * filtering. No further check is performed to assert that. 1431 * 1432 * This function will return %-EPERM if any if an attached program was found 1433 * and if it returned != 1 during execution. In all other cases, 0 is returned. 1434 */ 1435int __cgroup_bpf_run_filter_sk(struct sock *sk, 1436 enum cgroup_bpf_attach_type atype) 1437{ 1438 struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data); 1439 1440 return bpf_prog_run_array_cg(&cgrp->bpf, atype, sk, bpf_prog_run, 0, 1441 NULL); 1442} 1443EXPORT_SYMBOL(__cgroup_bpf_run_filter_sk); 1444 1445/** 1446 * __cgroup_bpf_run_filter_sock_addr() - Run a program on a sock and 1447 * provided by user sockaddr 1448 * @sk: sock struct that will use sockaddr 1449 * @uaddr: sockaddr struct provided by user 1450 * @uaddrlen: Pointer to the size of the sockaddr struct provided by user. It is 1451 * read-only for AF_INET[6] uaddr but can be modified for AF_UNIX 1452 * uaddr. 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, INET6 or UNIX. 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 */ 1463int __cgroup_bpf_run_filter_sock_addr(struct sock *sk, 1464 struct sockaddr *uaddr, 1465 int *uaddrlen, 1466 enum cgroup_bpf_attach_type atype, 1467 void *t_ctx, 1468 u32 *flags) 1469{ 1470 struct bpf_sock_addr_kern ctx = { 1471 .sk = sk, 1472 .uaddr = uaddr, 1473 .t_ctx = t_ctx, 1474 }; 1475 struct sockaddr_storage unspec; 1476 struct cgroup *cgrp; 1477 int ret; 1478 1479 /* Check socket family since not all sockets represent network 1480 * endpoint (e.g. AF_UNIX). 1481 */ 1482 if (sk->sk_family != AF_INET && sk->sk_family != AF_INET6 && 1483 sk->sk_family != AF_UNIX) 1484 return 0; 1485 1486 if (!ctx.uaddr) { 1487 memset(&unspec, 0, sizeof(unspec)); 1488 ctx.uaddr = (struct sockaddr *)&unspec; 1489 ctx.uaddrlen = 0; 1490 } else { 1491 ctx.uaddrlen = *uaddrlen; 1492 } 1493 1494 cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data); 1495 ret = bpf_prog_run_array_cg(&cgrp->bpf, atype, &ctx, bpf_prog_run, 1496 0, flags); 1497 1498 if (!ret && uaddr) 1499 *uaddrlen = ctx.uaddrlen; 1500 1501 return ret; 1502} 1503EXPORT_SYMBOL(__cgroup_bpf_run_filter_sock_addr); 1504 1505/** 1506 * __cgroup_bpf_run_filter_sock_ops() - Run a program on a sock 1507 * @sk: socket to get cgroup from 1508 * @sock_ops: bpf_sock_ops_kern struct to pass to program. Contains 1509 * sk with connection information (IP addresses, etc.) May not contain 1510 * cgroup info if it is a req sock. 1511 * @atype: The type of program to be executed 1512 * 1513 * socket passed is expected to be of type INET or INET6. 1514 * 1515 * The program type passed in via @type must be suitable for sock_ops 1516 * filtering. No further check is performed to assert that. 1517 * 1518 * This function will return %-EPERM if any if an attached program was found 1519 * and if it returned != 1 during execution. In all other cases, 0 is returned. 1520 */ 1521int __cgroup_bpf_run_filter_sock_ops(struct sock *sk, 1522 struct bpf_sock_ops_kern *sock_ops, 1523 enum cgroup_bpf_attach_type atype) 1524{ 1525 struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data); 1526 1527 return bpf_prog_run_array_cg(&cgrp->bpf, atype, sock_ops, bpf_prog_run, 1528 0, NULL); 1529} 1530EXPORT_SYMBOL(__cgroup_bpf_run_filter_sock_ops); 1531 1532int __cgroup_bpf_check_dev_permission(short dev_type, u32 major, u32 minor, 1533 short access, enum cgroup_bpf_attach_type atype) 1534{ 1535 struct cgroup *cgrp; 1536 struct bpf_cgroup_dev_ctx ctx = { 1537 .access_type = (access << 16) | dev_type, 1538 .major = major, 1539 .minor = minor, 1540 }; 1541 int ret; 1542 1543 rcu_read_lock(); 1544 cgrp = task_dfl_cgroup(current); 1545 ret = bpf_prog_run_array_cg(&cgrp->bpf, atype, &ctx, bpf_prog_run, 0, 1546 NULL); 1547 rcu_read_unlock(); 1548 1549 return ret; 1550} 1551 1552BPF_CALL_2(bpf_get_local_storage, struct bpf_map *, map, u64, flags) 1553{ 1554 /* flags argument is not used now, 1555 * but provides an ability to extend the API. 1556 * verifier checks that its value is correct. 1557 */ 1558 enum bpf_cgroup_storage_type stype = cgroup_storage_type(map); 1559 struct bpf_cgroup_storage *storage; 1560 struct bpf_cg_run_ctx *ctx; 1561 void *ptr; 1562 1563 /* get current cgroup storage from BPF run context */ 1564 ctx = container_of(current->bpf_ctx, struct bpf_cg_run_ctx, run_ctx); 1565 storage = ctx->prog_item->cgroup_storage[stype]; 1566 1567 if (stype == BPF_CGROUP_STORAGE_SHARED) 1568 ptr = &READ_ONCE(storage->buf)->data[0]; 1569 else 1570 ptr = this_cpu_ptr(storage->percpu_buf); 1571 1572 return (unsigned long)ptr; 1573} 1574 1575const struct bpf_func_proto bpf_get_local_storage_proto = { 1576 .func = bpf_get_local_storage, 1577 .gpl_only = false, 1578 .ret_type = RET_PTR_TO_MAP_VALUE, 1579 .arg1_type = ARG_CONST_MAP_PTR, 1580 .arg2_type = ARG_ANYTHING, 1581}; 1582 1583BPF_CALL_0(bpf_get_retval) 1584{ 1585 struct bpf_cg_run_ctx *ctx = 1586 container_of(current->bpf_ctx, struct bpf_cg_run_ctx, run_ctx); 1587 1588 return ctx->retval; 1589} 1590 1591const struct bpf_func_proto bpf_get_retval_proto = { 1592 .func = bpf_get_retval, 1593 .gpl_only = false, 1594 .ret_type = RET_INTEGER, 1595}; 1596 1597BPF_CALL_1(bpf_set_retval, int, retval) 1598{ 1599 struct bpf_cg_run_ctx *ctx = 1600 container_of(current->bpf_ctx, struct bpf_cg_run_ctx, run_ctx); 1601 1602 ctx->retval = retval; 1603 return 0; 1604} 1605 1606const struct bpf_func_proto bpf_set_retval_proto = { 1607 .func = bpf_set_retval, 1608 .gpl_only = false, 1609 .ret_type = RET_INTEGER, 1610 .arg1_type = ARG_ANYTHING, 1611}; 1612 1613static const struct bpf_func_proto * 1614cgroup_dev_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 1615{ 1616 const struct bpf_func_proto *func_proto; 1617 1618 func_proto = cgroup_common_func_proto(func_id, prog); 1619 if (func_proto) 1620 return func_proto; 1621 1622 func_proto = cgroup_current_func_proto(func_id, prog); 1623 if (func_proto) 1624 return func_proto; 1625 1626 switch (func_id) { 1627 case BPF_FUNC_perf_event_output: 1628 return &bpf_event_output_data_proto; 1629 default: 1630 return bpf_base_func_proto(func_id, prog); 1631 } 1632} 1633 1634static bool cgroup_dev_is_valid_access(int off, int size, 1635 enum bpf_access_type type, 1636 const struct bpf_prog *prog, 1637 struct bpf_insn_access_aux *info) 1638{ 1639 const int size_default = sizeof(__u32); 1640 1641 if (type == BPF_WRITE) 1642 return false; 1643 1644 if (off < 0 || off + size > sizeof(struct bpf_cgroup_dev_ctx)) 1645 return false; 1646 /* The verifier guarantees that size > 0. */ 1647 if (off % size != 0) 1648 return false; 1649 1650 switch (off) { 1651 case bpf_ctx_range(struct bpf_cgroup_dev_ctx, access_type): 1652 bpf_ctx_record_field_size(info, size_default); 1653 if (!bpf_ctx_narrow_access_ok(off, size, size_default)) 1654 return false; 1655 break; 1656 default: 1657 if (size != size_default) 1658 return false; 1659 } 1660 1661 return true; 1662} 1663 1664const struct bpf_prog_ops cg_dev_prog_ops = { 1665}; 1666 1667const struct bpf_verifier_ops cg_dev_verifier_ops = { 1668 .get_func_proto = cgroup_dev_func_proto, 1669 .is_valid_access = cgroup_dev_is_valid_access, 1670}; 1671 1672/** 1673 * __cgroup_bpf_run_filter_sysctl - Run a program on sysctl 1674 * 1675 * @head: sysctl table header 1676 * @table: sysctl table 1677 * @write: sysctl is being read (= 0) or written (= 1) 1678 * @buf: pointer to buffer (in and out) 1679 * @pcount: value-result argument: value is size of buffer pointed to by @buf, 1680 * result is size of @new_buf if program set new value, initial value 1681 * otherwise 1682 * @ppos: value-result argument: value is position at which read from or write 1683 * to sysctl is happening, result is new position if program overrode it, 1684 * initial value otherwise 1685 * @atype: type of program to be executed 1686 * 1687 * Program is run when sysctl is being accessed, either read or written, and 1688 * can allow or deny such access. 1689 * 1690 * This function will return %-EPERM if an attached program is found and 1691 * returned value != 1 during execution. In all other cases 0 is returned. 1692 */ 1693int __cgroup_bpf_run_filter_sysctl(struct ctl_table_header *head, 1694 struct ctl_table *table, int write, 1695 char **buf, size_t *pcount, loff_t *ppos, 1696 enum cgroup_bpf_attach_type atype) 1697{ 1698 struct bpf_sysctl_kern ctx = { 1699 .head = head, 1700 .table = table, 1701 .write = write, 1702 .ppos = ppos, 1703 .cur_val = NULL, 1704 .cur_len = PAGE_SIZE, 1705 .new_val = NULL, 1706 .new_len = 0, 1707 .new_updated = 0, 1708 }; 1709 struct cgroup *cgrp; 1710 loff_t pos = 0; 1711 int ret; 1712 1713 ctx.cur_val = kmalloc_track_caller(ctx.cur_len, GFP_KERNEL); 1714 if (!ctx.cur_val || 1715 table->proc_handler(table, 0, ctx.cur_val, &ctx.cur_len, &pos)) { 1716 /* Let BPF program decide how to proceed. */ 1717 ctx.cur_len = 0; 1718 } 1719 1720 if (write && *buf && *pcount) { 1721 /* BPF program should be able to override new value with a 1722 * buffer bigger than provided by user. 1723 */ 1724 ctx.new_val = kmalloc_track_caller(PAGE_SIZE, GFP_KERNEL); 1725 ctx.new_len = min_t(size_t, PAGE_SIZE, *pcount); 1726 if (ctx.new_val) { 1727 memcpy(ctx.new_val, *buf, ctx.new_len); 1728 } else { 1729 /* Let BPF program decide how to proceed. */ 1730 ctx.new_len = 0; 1731 } 1732 } 1733 1734 rcu_read_lock(); 1735 cgrp = task_dfl_cgroup(current); 1736 ret = bpf_prog_run_array_cg(&cgrp->bpf, atype, &ctx, bpf_prog_run, 0, 1737 NULL); 1738 rcu_read_unlock(); 1739 1740 kfree(ctx.cur_val); 1741 1742 if (ret == 1 && ctx.new_updated) { 1743 kfree(*buf); 1744 *buf = ctx.new_val; 1745 *pcount = ctx.new_len; 1746 } else { 1747 kfree(ctx.new_val); 1748 } 1749 1750 return ret; 1751} 1752 1753#ifdef CONFIG_NET 1754static int sockopt_alloc_buf(struct bpf_sockopt_kern *ctx, int max_optlen, 1755 struct bpf_sockopt_buf *buf) 1756{ 1757 if (unlikely(max_optlen < 0)) 1758 return -EINVAL; 1759 1760 if (unlikely(max_optlen > PAGE_SIZE)) { 1761 /* We don't expose optvals that are greater than PAGE_SIZE 1762 * to the BPF program. 1763 */ 1764 max_optlen = PAGE_SIZE; 1765 } 1766 1767 if (max_optlen <= sizeof(buf->data)) { 1768 /* When the optval fits into BPF_SOCKOPT_KERN_BUF_SIZE 1769 * bytes avoid the cost of kzalloc. 1770 */ 1771 ctx->optval = buf->data; 1772 ctx->optval_end = ctx->optval + max_optlen; 1773 return max_optlen; 1774 } 1775 1776 ctx->optval = kzalloc(max_optlen, GFP_USER); 1777 if (!ctx->optval) 1778 return -ENOMEM; 1779 1780 ctx->optval_end = ctx->optval + max_optlen; 1781 1782 return max_optlen; 1783} 1784 1785static void sockopt_free_buf(struct bpf_sockopt_kern *ctx, 1786 struct bpf_sockopt_buf *buf) 1787{ 1788 if (ctx->optval == buf->data) 1789 return; 1790 kfree(ctx->optval); 1791} 1792 1793static bool sockopt_buf_allocated(struct bpf_sockopt_kern *ctx, 1794 struct bpf_sockopt_buf *buf) 1795{ 1796 return ctx->optval != buf->data; 1797} 1798 1799int __cgroup_bpf_run_filter_setsockopt(struct sock *sk, int *level, 1800 int *optname, sockptr_t optval, 1801 int *optlen, char **kernel_optval) 1802{ 1803 struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data); 1804 struct bpf_sockopt_buf buf = {}; 1805 struct bpf_sockopt_kern ctx = { 1806 .sk = sk, 1807 .level = *level, 1808 .optname = *optname, 1809 }; 1810 int ret, max_optlen; 1811 1812 /* Allocate a bit more than the initial user buffer for 1813 * BPF program. The canonical use case is overriding 1814 * TCP_CONGESTION(nv) to TCP_CONGESTION(cubic). 1815 */ 1816 max_optlen = max_t(int, 16, *optlen); 1817 max_optlen = sockopt_alloc_buf(&ctx, max_optlen, &buf); 1818 if (max_optlen < 0) 1819 return max_optlen; 1820 1821 ctx.optlen = *optlen; 1822 1823 if (copy_from_sockptr(ctx.optval, optval, 1824 min(*optlen, max_optlen))) { 1825 ret = -EFAULT; 1826 goto out; 1827 } 1828 1829 lock_sock(sk); 1830 ret = bpf_prog_run_array_cg(&cgrp->bpf, CGROUP_SETSOCKOPT, 1831 &ctx, bpf_prog_run, 0, NULL); 1832 release_sock(sk); 1833 1834 if (ret) 1835 goto out; 1836 1837 if (ctx.optlen == -1) { 1838 /* optlen set to -1, bypass kernel */ 1839 ret = 1; 1840 } else if (ctx.optlen > max_optlen || ctx.optlen < -1) { 1841 /* optlen is out of bounds */ 1842 if (*optlen > PAGE_SIZE && ctx.optlen >= 0) { 1843 pr_info_once("bpf setsockopt: ignoring program buffer with optlen=%d (max_optlen=%d)\n", 1844 ctx.optlen, max_optlen); 1845 ret = 0; 1846 goto out; 1847 } 1848 ret = -EFAULT; 1849 } else { 1850 /* optlen within bounds, run kernel handler */ 1851 ret = 0; 1852 1853 /* export any potential modifications */ 1854 *level = ctx.level; 1855 *optname = ctx.optname; 1856 1857 /* optlen == 0 from BPF indicates that we should 1858 * use original userspace data. 1859 */ 1860 if (ctx.optlen != 0) { 1861 *optlen = ctx.optlen; 1862 /* We've used bpf_sockopt_kern->buf as an intermediary 1863 * storage, but the BPF program indicates that we need 1864 * to pass this data to the kernel setsockopt handler. 1865 * No way to export on-stack buf, have to allocate a 1866 * new buffer. 1867 */ 1868 if (!sockopt_buf_allocated(&ctx, &buf)) { 1869 void *p = kmalloc(ctx.optlen, GFP_USER); 1870 1871 if (!p) { 1872 ret = -ENOMEM; 1873 goto out; 1874 } 1875 memcpy(p, ctx.optval, ctx.optlen); 1876 *kernel_optval = p; 1877 } else { 1878 *kernel_optval = ctx.optval; 1879 } 1880 /* export and don't free sockopt buf */ 1881 return 0; 1882 } 1883 } 1884 1885out: 1886 sockopt_free_buf(&ctx, &buf); 1887 return ret; 1888} 1889 1890int __cgroup_bpf_run_filter_getsockopt(struct sock *sk, int level, 1891 int optname, sockptr_t optval, 1892 sockptr_t optlen, int max_optlen, 1893 int retval) 1894{ 1895 struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data); 1896 struct bpf_sockopt_buf buf = {}; 1897 struct bpf_sockopt_kern ctx = { 1898 .sk = sk, 1899 .level = level, 1900 .optname = optname, 1901 .current_task = current, 1902 }; 1903 int orig_optlen; 1904 int ret; 1905 1906 orig_optlen = max_optlen; 1907 ctx.optlen = max_optlen; 1908 max_optlen = sockopt_alloc_buf(&ctx, max_optlen, &buf); 1909 if (max_optlen < 0) 1910 return max_optlen; 1911 1912 if (!retval) { 1913 /* If kernel getsockopt finished successfully, 1914 * copy whatever was returned to the user back 1915 * into our temporary buffer. Set optlen to the 1916 * one that kernel returned as well to let 1917 * BPF programs inspect the value. 1918 */ 1919 if (copy_from_sockptr(&ctx.optlen, optlen, 1920 sizeof(ctx.optlen))) { 1921 ret = -EFAULT; 1922 goto out; 1923 } 1924 1925 if (ctx.optlen < 0) { 1926 ret = -EFAULT; 1927 goto out; 1928 } 1929 orig_optlen = ctx.optlen; 1930 1931 if (copy_from_sockptr(ctx.optval, optval, 1932 min(ctx.optlen, max_optlen))) { 1933 ret = -EFAULT; 1934 goto out; 1935 } 1936 } 1937 1938 lock_sock(sk); 1939 ret = bpf_prog_run_array_cg(&cgrp->bpf, CGROUP_GETSOCKOPT, 1940 &ctx, bpf_prog_run, retval, NULL); 1941 release_sock(sk); 1942 1943 if (ret < 0) 1944 goto out; 1945 1946 if (!sockptr_is_null(optval) && 1947 (ctx.optlen > max_optlen || ctx.optlen < 0)) { 1948 if (orig_optlen > PAGE_SIZE && ctx.optlen >= 0) { 1949 pr_info_once("bpf getsockopt: ignoring program buffer with optlen=%d (max_optlen=%d)\n", 1950 ctx.optlen, max_optlen); 1951 ret = retval; 1952 goto out; 1953 } 1954 ret = -EFAULT; 1955 goto out; 1956 } 1957 1958 if (ctx.optlen != 0) { 1959 if (!sockptr_is_null(optval) && 1960 copy_to_sockptr(optval, ctx.optval, ctx.optlen)) { 1961 ret = -EFAULT; 1962 goto out; 1963 } 1964 if (copy_to_sockptr(optlen, &ctx.optlen, sizeof(ctx.optlen))) { 1965 ret = -EFAULT; 1966 goto out; 1967 } 1968 } 1969 1970out: 1971 sockopt_free_buf(&ctx, &buf); 1972 return ret; 1973} 1974 1975int __cgroup_bpf_run_filter_getsockopt_kern(struct sock *sk, int level, 1976 int optname, void *optval, 1977 int *optlen, int retval) 1978{ 1979 struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data); 1980 struct bpf_sockopt_kern ctx = { 1981 .sk = sk, 1982 .level = level, 1983 .optname = optname, 1984 .optlen = *optlen, 1985 .optval = optval, 1986 .optval_end = optval + *optlen, 1987 .current_task = current, 1988 }; 1989 int ret; 1990 1991 /* Note that __cgroup_bpf_run_filter_getsockopt doesn't copy 1992 * user data back into BPF buffer when reval != 0. This is 1993 * done as an optimization to avoid extra copy, assuming 1994 * kernel won't populate the data in case of an error. 1995 * Here we always pass the data and memset() should 1996 * be called if that data shouldn't be "exported". 1997 */ 1998 1999 ret = bpf_prog_run_array_cg(&cgrp->bpf, CGROUP_GETSOCKOPT, 2000 &ctx, bpf_prog_run, retval, NULL); 2001 if (ret < 0) 2002 return ret; 2003 2004 if (ctx.optlen > *optlen) 2005 return -EFAULT; 2006 2007 /* BPF programs can shrink the buffer, export the modifications. 2008 */ 2009 if (ctx.optlen != 0) 2010 *optlen = ctx.optlen; 2011 2012 return ret; 2013} 2014#endif 2015 2016static ssize_t sysctl_cpy_dir(const struct ctl_dir *dir, char **bufp, 2017 size_t *lenp) 2018{ 2019 ssize_t tmp_ret = 0, ret; 2020 2021 if (dir->header.parent) { 2022 tmp_ret = sysctl_cpy_dir(dir->header.parent, bufp, lenp); 2023 if (tmp_ret < 0) 2024 return tmp_ret; 2025 } 2026 2027 ret = strscpy(*bufp, dir->header.ctl_table[0].procname, *lenp); 2028 if (ret < 0) 2029 return ret; 2030 *bufp += ret; 2031 *lenp -= ret; 2032 ret += tmp_ret; 2033 2034 /* Avoid leading slash. */ 2035 if (!ret) 2036 return ret; 2037 2038 tmp_ret = strscpy(*bufp, "/", *lenp); 2039 if (tmp_ret < 0) 2040 return tmp_ret; 2041 *bufp += tmp_ret; 2042 *lenp -= tmp_ret; 2043 2044 return ret + tmp_ret; 2045} 2046 2047BPF_CALL_4(bpf_sysctl_get_name, struct bpf_sysctl_kern *, ctx, char *, buf, 2048 size_t, buf_len, u64, flags) 2049{ 2050 ssize_t tmp_ret = 0, ret; 2051 2052 if (!buf) 2053 return -EINVAL; 2054 2055 if (!(flags & BPF_F_SYSCTL_BASE_NAME)) { 2056 if (!ctx->head) 2057 return -EINVAL; 2058 tmp_ret = sysctl_cpy_dir(ctx->head->parent, &buf, &buf_len); 2059 if (tmp_ret < 0) 2060 return tmp_ret; 2061 } 2062 2063 ret = strscpy(buf, ctx->table->procname, buf_len); 2064 2065 return ret < 0 ? ret : tmp_ret + ret; 2066} 2067 2068static const struct bpf_func_proto bpf_sysctl_get_name_proto = { 2069 .func = bpf_sysctl_get_name, 2070 .gpl_only = false, 2071 .ret_type = RET_INTEGER, 2072 .arg1_type = ARG_PTR_TO_CTX, 2073 .arg2_type = ARG_PTR_TO_MEM, 2074 .arg3_type = ARG_CONST_SIZE, 2075 .arg4_type = ARG_ANYTHING, 2076}; 2077 2078static int copy_sysctl_value(char *dst, size_t dst_len, char *src, 2079 size_t src_len) 2080{ 2081 if (!dst) 2082 return -EINVAL; 2083 2084 if (!dst_len) 2085 return -E2BIG; 2086 2087 if (!src || !src_len) { 2088 memset(dst, 0, dst_len); 2089 return -EINVAL; 2090 } 2091 2092 memcpy(dst, src, min(dst_len, src_len)); 2093 2094 if (dst_len > src_len) { 2095 memset(dst + src_len, '\0', dst_len - src_len); 2096 return src_len; 2097 } 2098 2099 dst[dst_len - 1] = '\0'; 2100 2101 return -E2BIG; 2102} 2103 2104BPF_CALL_3(bpf_sysctl_get_current_value, struct bpf_sysctl_kern *, ctx, 2105 char *, buf, size_t, buf_len) 2106{ 2107 return copy_sysctl_value(buf, buf_len, ctx->cur_val, ctx->cur_len); 2108} 2109 2110static const struct bpf_func_proto bpf_sysctl_get_current_value_proto = { 2111 .func = bpf_sysctl_get_current_value, 2112 .gpl_only = false, 2113 .ret_type = RET_INTEGER, 2114 .arg1_type = ARG_PTR_TO_CTX, 2115 .arg2_type = ARG_PTR_TO_UNINIT_MEM, 2116 .arg3_type = ARG_CONST_SIZE, 2117}; 2118 2119BPF_CALL_3(bpf_sysctl_get_new_value, struct bpf_sysctl_kern *, ctx, char *, buf, 2120 size_t, buf_len) 2121{ 2122 if (!ctx->write) { 2123 if (buf && buf_len) 2124 memset(buf, '\0', buf_len); 2125 return -EINVAL; 2126 } 2127 return copy_sysctl_value(buf, buf_len, ctx->new_val, ctx->new_len); 2128} 2129 2130static const struct bpf_func_proto bpf_sysctl_get_new_value_proto = { 2131 .func = bpf_sysctl_get_new_value, 2132 .gpl_only = false, 2133 .ret_type = RET_INTEGER, 2134 .arg1_type = ARG_PTR_TO_CTX, 2135 .arg2_type = ARG_PTR_TO_UNINIT_MEM, 2136 .arg3_type = ARG_CONST_SIZE, 2137}; 2138 2139BPF_CALL_3(bpf_sysctl_set_new_value, struct bpf_sysctl_kern *, ctx, 2140 const char *, buf, size_t, buf_len) 2141{ 2142 if (!ctx->write || !ctx->new_val || !ctx->new_len || !buf || !buf_len) 2143 return -EINVAL; 2144 2145 if (buf_len > PAGE_SIZE - 1) 2146 return -E2BIG; 2147 2148 memcpy(ctx->new_val, buf, buf_len); 2149 ctx->new_len = buf_len; 2150 ctx->new_updated = 1; 2151 2152 return 0; 2153} 2154 2155static const struct bpf_func_proto bpf_sysctl_set_new_value_proto = { 2156 .func = bpf_sysctl_set_new_value, 2157 .gpl_only = false, 2158 .ret_type = RET_INTEGER, 2159 .arg1_type = ARG_PTR_TO_CTX, 2160 .arg2_type = ARG_PTR_TO_MEM | MEM_RDONLY, 2161 .arg3_type = ARG_CONST_SIZE, 2162}; 2163 2164static const struct bpf_func_proto * 2165sysctl_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 2166{ 2167 const struct bpf_func_proto *func_proto; 2168 2169 func_proto = cgroup_common_func_proto(func_id, prog); 2170 if (func_proto) 2171 return func_proto; 2172 2173 func_proto = cgroup_current_func_proto(func_id, prog); 2174 if (func_proto) 2175 return func_proto; 2176 2177 switch (func_id) { 2178 case BPF_FUNC_sysctl_get_name: 2179 return &bpf_sysctl_get_name_proto; 2180 case BPF_FUNC_sysctl_get_current_value: 2181 return &bpf_sysctl_get_current_value_proto; 2182 case BPF_FUNC_sysctl_get_new_value: 2183 return &bpf_sysctl_get_new_value_proto; 2184 case BPF_FUNC_sysctl_set_new_value: 2185 return &bpf_sysctl_set_new_value_proto; 2186 case BPF_FUNC_ktime_get_coarse_ns: 2187 return &bpf_ktime_get_coarse_ns_proto; 2188 case BPF_FUNC_perf_event_output: 2189 return &bpf_event_output_data_proto; 2190 default: 2191 return bpf_base_func_proto(func_id, prog); 2192 } 2193} 2194 2195static bool sysctl_is_valid_access(int off, int size, enum bpf_access_type type, 2196 const struct bpf_prog *prog, 2197 struct bpf_insn_access_aux *info) 2198{ 2199 const int size_default = sizeof(__u32); 2200 2201 if (off < 0 || off + size > sizeof(struct bpf_sysctl) || off % size) 2202 return false; 2203 2204 switch (off) { 2205 case bpf_ctx_range(struct bpf_sysctl, write): 2206 if (type != BPF_READ) 2207 return false; 2208 bpf_ctx_record_field_size(info, size_default); 2209 return bpf_ctx_narrow_access_ok(off, size, size_default); 2210 case bpf_ctx_range(struct bpf_sysctl, file_pos): 2211 if (type == BPF_READ) { 2212 bpf_ctx_record_field_size(info, size_default); 2213 return bpf_ctx_narrow_access_ok(off, size, size_default); 2214 } else { 2215 return size == size_default; 2216 } 2217 default: 2218 return false; 2219 } 2220} 2221 2222static u32 sysctl_convert_ctx_access(enum bpf_access_type type, 2223 const struct bpf_insn *si, 2224 struct bpf_insn *insn_buf, 2225 struct bpf_prog *prog, u32 *target_size) 2226{ 2227 struct bpf_insn *insn = insn_buf; 2228 u32 read_size; 2229 2230 switch (si->off) { 2231 case offsetof(struct bpf_sysctl, write): 2232 *insn++ = BPF_LDX_MEM( 2233 BPF_SIZE(si->code), si->dst_reg, si->src_reg, 2234 bpf_target_off(struct bpf_sysctl_kern, write, 2235 sizeof_field(struct bpf_sysctl_kern, 2236 write), 2237 target_size)); 2238 break; 2239 case offsetof(struct bpf_sysctl, file_pos): 2240 /* ppos is a pointer so it should be accessed via indirect 2241 * loads and stores. Also for stores additional temporary 2242 * register is used since neither src_reg nor dst_reg can be 2243 * overridden. 2244 */ 2245 if (type == BPF_WRITE) { 2246 int treg = BPF_REG_9; 2247 2248 if (si->src_reg == treg || si->dst_reg == treg) 2249 --treg; 2250 if (si->src_reg == treg || si->dst_reg == treg) 2251 --treg; 2252 *insn++ = BPF_STX_MEM( 2253 BPF_DW, si->dst_reg, treg, 2254 offsetof(struct bpf_sysctl_kern, tmp_reg)); 2255 *insn++ = BPF_LDX_MEM( 2256 BPF_FIELD_SIZEOF(struct bpf_sysctl_kern, ppos), 2257 treg, si->dst_reg, 2258 offsetof(struct bpf_sysctl_kern, ppos)); 2259 *insn++ = BPF_RAW_INSN( 2260 BPF_CLASS(si->code) | BPF_MEM | BPF_SIZEOF(u32), 2261 treg, si->src_reg, 2262 bpf_ctx_narrow_access_offset( 2263 0, sizeof(u32), sizeof(loff_t)), 2264 si->imm); 2265 *insn++ = BPF_LDX_MEM( 2266 BPF_DW, treg, si->dst_reg, 2267 offsetof(struct bpf_sysctl_kern, tmp_reg)); 2268 } else { 2269 *insn++ = BPF_LDX_MEM( 2270 BPF_FIELD_SIZEOF(struct bpf_sysctl_kern, ppos), 2271 si->dst_reg, si->src_reg, 2272 offsetof(struct bpf_sysctl_kern, ppos)); 2273 read_size = bpf_size_to_bytes(BPF_SIZE(si->code)); 2274 *insn++ = BPF_LDX_MEM( 2275 BPF_SIZE(si->code), si->dst_reg, si->dst_reg, 2276 bpf_ctx_narrow_access_offset( 2277 0, read_size, sizeof(loff_t))); 2278 } 2279 *target_size = sizeof(u32); 2280 break; 2281 } 2282 2283 return insn - insn_buf; 2284} 2285 2286const struct bpf_verifier_ops cg_sysctl_verifier_ops = { 2287 .get_func_proto = sysctl_func_proto, 2288 .is_valid_access = sysctl_is_valid_access, 2289 .convert_ctx_access = sysctl_convert_ctx_access, 2290}; 2291 2292const struct bpf_prog_ops cg_sysctl_prog_ops = { 2293}; 2294 2295#ifdef CONFIG_NET 2296BPF_CALL_1(bpf_get_netns_cookie_sockopt, struct bpf_sockopt_kern *, ctx) 2297{ 2298 const struct net *net = ctx ? sock_net(ctx->sk) : &init_net; 2299 2300 return net->net_cookie; 2301} 2302 2303static const struct bpf_func_proto bpf_get_netns_cookie_sockopt_proto = { 2304 .func = bpf_get_netns_cookie_sockopt, 2305 .gpl_only = false, 2306 .ret_type = RET_INTEGER, 2307 .arg1_type = ARG_PTR_TO_CTX_OR_NULL, 2308}; 2309#endif 2310 2311static const struct bpf_func_proto * 2312cg_sockopt_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 2313{ 2314 const struct bpf_func_proto *func_proto; 2315 2316 func_proto = cgroup_common_func_proto(func_id, prog); 2317 if (func_proto) 2318 return func_proto; 2319 2320 func_proto = cgroup_current_func_proto(func_id, prog); 2321 if (func_proto) 2322 return func_proto; 2323 2324 switch (func_id) { 2325#ifdef CONFIG_NET 2326 case BPF_FUNC_get_netns_cookie: 2327 return &bpf_get_netns_cookie_sockopt_proto; 2328 case BPF_FUNC_sk_storage_get: 2329 return &bpf_sk_storage_get_proto; 2330 case BPF_FUNC_sk_storage_delete: 2331 return &bpf_sk_storage_delete_proto; 2332 case BPF_FUNC_setsockopt: 2333 if (prog->expected_attach_type == BPF_CGROUP_SETSOCKOPT) 2334 return &bpf_sk_setsockopt_proto; 2335 return NULL; 2336 case BPF_FUNC_getsockopt: 2337 if (prog->expected_attach_type == BPF_CGROUP_SETSOCKOPT) 2338 return &bpf_sk_getsockopt_proto; 2339 return NULL; 2340#endif 2341#ifdef CONFIG_INET 2342 case BPF_FUNC_tcp_sock: 2343 return &bpf_tcp_sock_proto; 2344#endif 2345 case BPF_FUNC_perf_event_output: 2346 return &bpf_event_output_data_proto; 2347 default: 2348 return bpf_base_func_proto(func_id, prog); 2349 } 2350} 2351 2352static bool cg_sockopt_is_valid_access(int off, int size, 2353 enum bpf_access_type type, 2354 const struct bpf_prog *prog, 2355 struct bpf_insn_access_aux *info) 2356{ 2357 const int size_default = sizeof(__u32); 2358 2359 if (off < 0 || off >= sizeof(struct bpf_sockopt)) 2360 return false; 2361 2362 if (off % size != 0) 2363 return false; 2364 2365 if (type == BPF_WRITE) { 2366 switch (off) { 2367 case offsetof(struct bpf_sockopt, retval): 2368 if (size != size_default) 2369 return false; 2370 return prog->expected_attach_type == 2371 BPF_CGROUP_GETSOCKOPT; 2372 case offsetof(struct bpf_sockopt, optname): 2373 fallthrough; 2374 case offsetof(struct bpf_sockopt, level): 2375 if (size != size_default) 2376 return false; 2377 return prog->expected_attach_type == 2378 BPF_CGROUP_SETSOCKOPT; 2379 case offsetof(struct bpf_sockopt, optlen): 2380 return size == size_default; 2381 default: 2382 return false; 2383 } 2384 } 2385 2386 switch (off) { 2387 case offsetof(struct bpf_sockopt, sk): 2388 if (size != sizeof(__u64)) 2389 return false; 2390 info->reg_type = PTR_TO_SOCKET; 2391 break; 2392 case offsetof(struct bpf_sockopt, optval): 2393 if (size != sizeof(__u64)) 2394 return false; 2395 info->reg_type = PTR_TO_PACKET; 2396 break; 2397 case offsetof(struct bpf_sockopt, optval_end): 2398 if (size != sizeof(__u64)) 2399 return false; 2400 info->reg_type = PTR_TO_PACKET_END; 2401 break; 2402 case offsetof(struct bpf_sockopt, retval): 2403 if (size != size_default) 2404 return false; 2405 return prog->expected_attach_type == BPF_CGROUP_GETSOCKOPT; 2406 default: 2407 if (size != size_default) 2408 return false; 2409 break; 2410 } 2411 return true; 2412} 2413 2414#define CG_SOCKOPT_READ_FIELD(F) \ 2415 BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_sockopt_kern, F), \ 2416 si->dst_reg, si->src_reg, \ 2417 offsetof(struct bpf_sockopt_kern, F)) 2418 2419#define CG_SOCKOPT_WRITE_FIELD(F) \ 2420 BPF_RAW_INSN((BPF_FIELD_SIZEOF(struct bpf_sockopt_kern, F) | \ 2421 BPF_MEM | BPF_CLASS(si->code)), \ 2422 si->dst_reg, si->src_reg, \ 2423 offsetof(struct bpf_sockopt_kern, F), \ 2424 si->imm) 2425 2426static u32 cg_sockopt_convert_ctx_access(enum bpf_access_type type, 2427 const struct bpf_insn *si, 2428 struct bpf_insn *insn_buf, 2429 struct bpf_prog *prog, 2430 u32 *target_size) 2431{ 2432 struct bpf_insn *insn = insn_buf; 2433 2434 switch (si->off) { 2435 case offsetof(struct bpf_sockopt, sk): 2436 *insn++ = CG_SOCKOPT_READ_FIELD(sk); 2437 break; 2438 case offsetof(struct bpf_sockopt, level): 2439 if (type == BPF_WRITE) 2440 *insn++ = CG_SOCKOPT_WRITE_FIELD(level); 2441 else 2442 *insn++ = CG_SOCKOPT_READ_FIELD(level); 2443 break; 2444 case offsetof(struct bpf_sockopt, optname): 2445 if (type == BPF_WRITE) 2446 *insn++ = CG_SOCKOPT_WRITE_FIELD(optname); 2447 else 2448 *insn++ = CG_SOCKOPT_READ_FIELD(optname); 2449 break; 2450 case offsetof(struct bpf_sockopt, optlen): 2451 if (type == BPF_WRITE) 2452 *insn++ = CG_SOCKOPT_WRITE_FIELD(optlen); 2453 else 2454 *insn++ = CG_SOCKOPT_READ_FIELD(optlen); 2455 break; 2456 case offsetof(struct bpf_sockopt, retval): 2457 BUILD_BUG_ON(offsetof(struct bpf_cg_run_ctx, run_ctx) != 0); 2458 2459 if (type == BPF_WRITE) { 2460 int treg = BPF_REG_9; 2461 2462 if (si->src_reg == treg || si->dst_reg == treg) 2463 --treg; 2464 if (si->src_reg == treg || si->dst_reg == treg) 2465 --treg; 2466 *insn++ = BPF_STX_MEM(BPF_DW, si->dst_reg, treg, 2467 offsetof(struct bpf_sockopt_kern, tmp_reg)); 2468 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_sockopt_kern, current_task), 2469 treg, si->dst_reg, 2470 offsetof(struct bpf_sockopt_kern, current_task)); 2471 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct task_struct, bpf_ctx), 2472 treg, treg, 2473 offsetof(struct task_struct, bpf_ctx)); 2474 *insn++ = BPF_RAW_INSN(BPF_CLASS(si->code) | BPF_MEM | 2475 BPF_FIELD_SIZEOF(struct bpf_cg_run_ctx, retval), 2476 treg, si->src_reg, 2477 offsetof(struct bpf_cg_run_ctx, retval), 2478 si->imm); 2479 *insn++ = BPF_LDX_MEM(BPF_DW, treg, si->dst_reg, 2480 offsetof(struct bpf_sockopt_kern, tmp_reg)); 2481 } else { 2482 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_sockopt_kern, current_task), 2483 si->dst_reg, si->src_reg, 2484 offsetof(struct bpf_sockopt_kern, current_task)); 2485 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct task_struct, bpf_ctx), 2486 si->dst_reg, si->dst_reg, 2487 offsetof(struct task_struct, bpf_ctx)); 2488 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_cg_run_ctx, retval), 2489 si->dst_reg, si->dst_reg, 2490 offsetof(struct bpf_cg_run_ctx, retval)); 2491 } 2492 break; 2493 case offsetof(struct bpf_sockopt, optval): 2494 *insn++ = CG_SOCKOPT_READ_FIELD(optval); 2495 break; 2496 case offsetof(struct bpf_sockopt, optval_end): 2497 *insn++ = CG_SOCKOPT_READ_FIELD(optval_end); 2498 break; 2499 } 2500 2501 return insn - insn_buf; 2502} 2503 2504static int cg_sockopt_get_prologue(struct bpf_insn *insn_buf, 2505 bool direct_write, 2506 const struct bpf_prog *prog) 2507{ 2508 /* Nothing to do for sockopt argument. The data is kzalloc'ated. 2509 */ 2510 return 0; 2511} 2512 2513const struct bpf_verifier_ops cg_sockopt_verifier_ops = { 2514 .get_func_proto = cg_sockopt_func_proto, 2515 .is_valid_access = cg_sockopt_is_valid_access, 2516 .convert_ctx_access = cg_sockopt_convert_ctx_access, 2517 .gen_prologue = cg_sockopt_get_prologue, 2518}; 2519 2520const struct bpf_prog_ops cg_sockopt_prog_ops = { 2521}; 2522 2523/* Common helpers for cgroup hooks. */ 2524const struct bpf_func_proto * 2525cgroup_common_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 2526{ 2527 switch (func_id) { 2528 case BPF_FUNC_get_local_storage: 2529 return &bpf_get_local_storage_proto; 2530 case BPF_FUNC_get_retval: 2531 switch (prog->expected_attach_type) { 2532 case BPF_CGROUP_INET_INGRESS: 2533 case BPF_CGROUP_INET_EGRESS: 2534 case BPF_CGROUP_SOCK_OPS: 2535 case BPF_CGROUP_UDP4_RECVMSG: 2536 case BPF_CGROUP_UDP6_RECVMSG: 2537 case BPF_CGROUP_UNIX_RECVMSG: 2538 case BPF_CGROUP_INET4_GETPEERNAME: 2539 case BPF_CGROUP_INET6_GETPEERNAME: 2540 case BPF_CGROUP_UNIX_GETPEERNAME: 2541 case BPF_CGROUP_INET4_GETSOCKNAME: 2542 case BPF_CGROUP_INET6_GETSOCKNAME: 2543 case BPF_CGROUP_UNIX_GETSOCKNAME: 2544 return NULL; 2545 default: 2546 return &bpf_get_retval_proto; 2547 } 2548 case BPF_FUNC_set_retval: 2549 switch (prog->expected_attach_type) { 2550 case BPF_CGROUP_INET_INGRESS: 2551 case BPF_CGROUP_INET_EGRESS: 2552 case BPF_CGROUP_SOCK_OPS: 2553 case BPF_CGROUP_UDP4_RECVMSG: 2554 case BPF_CGROUP_UDP6_RECVMSG: 2555 case BPF_CGROUP_UNIX_RECVMSG: 2556 case BPF_CGROUP_INET4_GETPEERNAME: 2557 case BPF_CGROUP_INET6_GETPEERNAME: 2558 case BPF_CGROUP_UNIX_GETPEERNAME: 2559 case BPF_CGROUP_INET4_GETSOCKNAME: 2560 case BPF_CGROUP_INET6_GETSOCKNAME: 2561 case BPF_CGROUP_UNIX_GETSOCKNAME: 2562 return NULL; 2563 default: 2564 return &bpf_set_retval_proto; 2565 } 2566 default: 2567 return NULL; 2568 } 2569} 2570 2571/* Common helpers for cgroup hooks with valid process context. */ 2572const struct bpf_func_proto * 2573cgroup_current_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 2574{ 2575 switch (func_id) { 2576 case BPF_FUNC_get_current_uid_gid: 2577 return &bpf_get_current_uid_gid_proto; 2578 case BPF_FUNC_get_current_pid_tgid: 2579 return &bpf_get_current_pid_tgid_proto; 2580 case BPF_FUNC_get_current_comm: 2581 return &bpf_get_current_comm_proto; 2582#ifdef CONFIG_CGROUP_NET_CLASSID 2583 case BPF_FUNC_get_cgroup_classid: 2584 return &bpf_get_cgroup_classid_curr_proto; 2585#endif 2586 default: 2587 return NULL; 2588 } 2589} 2590