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 <net/sock.h> 18 #include <net/bpf_sk_storage.h> 19 20 #include "../cgroup/cgroup-internal.h" 21 22 DEFINE_STATIC_KEY_ARRAY_FALSE(cgroup_bpf_enabled_key, MAX_CGROUP_BPF_ATTACH_TYPE); 23 EXPORT_SYMBOL(cgroup_bpf_enabled_key); 24 25 void cgroup_bpf_offline(struct cgroup *cgrp) 26 { 27 cgroup_get(cgrp); 28 percpu_ref_kill(&cgrp->bpf.refcnt); 29 } 30 31 static void bpf_cgroup_storages_free(struct bpf_cgroup_storage *storages[]) 32 { 33 enum bpf_cgroup_storage_type stype; 34 35 for_each_cgroup_storage_type(stype) 36 bpf_cgroup_storage_free(storages[stype]); 37 } 38 39 static int bpf_cgroup_storages_alloc(struct bpf_cgroup_storage *storages[], 40 struct bpf_cgroup_storage *new_storages[], 41 enum bpf_attach_type type, 42 struct bpf_prog *prog, 43 struct cgroup *cgrp) 44 { 45 enum bpf_cgroup_storage_type stype; 46 struct bpf_cgroup_storage_key key; 47 struct bpf_map *map; 48 49 key.cgroup_inode_id = cgroup_id(cgrp); 50 key.attach_type = type; 51 52 for_each_cgroup_storage_type(stype) { 53 map = prog->aux->cgroup_storage[stype]; 54 if (!map) 55 continue; 56 57 storages[stype] = cgroup_storage_lookup((void *)map, &key, false); 58 if (storages[stype]) 59 continue; 60 61 storages[stype] = bpf_cgroup_storage_alloc(prog, stype); 62 if (IS_ERR(storages[stype])) { 63 bpf_cgroup_storages_free(new_storages); 64 return -ENOMEM; 65 } 66 67 new_storages[stype] = storages[stype]; 68 } 69 70 return 0; 71 } 72 73 static void bpf_cgroup_storages_assign(struct bpf_cgroup_storage *dst[], 74 struct bpf_cgroup_storage *src[]) 75 { 76 enum bpf_cgroup_storage_type stype; 77 78 for_each_cgroup_storage_type(stype) 79 dst[stype] = src[stype]; 80 } 81 82 static void bpf_cgroup_storages_link(struct bpf_cgroup_storage *storages[], 83 struct cgroup *cgrp, 84 enum bpf_attach_type attach_type) 85 { 86 enum bpf_cgroup_storage_type stype; 87 88 for_each_cgroup_storage_type(stype) 89 bpf_cgroup_storage_link(storages[stype], cgrp, attach_type); 90 } 91 92 /* Called when bpf_cgroup_link is auto-detached from dying cgroup. 93 * It drops cgroup and bpf_prog refcounts, and marks bpf_link as defunct. It 94 * doesn't free link memory, which will eventually be done by bpf_link's 95 * release() callback, when its last FD is closed. 96 */ 97 static void bpf_cgroup_link_auto_detach(struct bpf_cgroup_link *link) 98 { 99 cgroup_put(link->cgroup); 100 link->cgroup = NULL; 101 } 102 103 /** 104 * cgroup_bpf_release() - put references of all bpf programs and 105 * release all cgroup bpf data 106 * @work: work structure embedded into the cgroup to modify 107 */ 108 static void cgroup_bpf_release(struct work_struct *work) 109 { 110 struct cgroup *p, *cgrp = container_of(work, struct cgroup, 111 bpf.release_work); 112 struct bpf_prog_array *old_array; 113 struct list_head *storages = &cgrp->bpf.storages; 114 struct bpf_cgroup_storage *storage, *stmp; 115 116 unsigned int atype; 117 118 mutex_lock(&cgroup_mutex); 119 120 for (atype = 0; atype < ARRAY_SIZE(cgrp->bpf.progs); atype++) { 121 struct list_head *progs = &cgrp->bpf.progs[atype]; 122 struct bpf_prog_list *pl, *pltmp; 123 124 list_for_each_entry_safe(pl, pltmp, progs, node) { 125 list_del(&pl->node); 126 if (pl->prog) 127 bpf_prog_put(pl->prog); 128 if (pl->link) 129 bpf_cgroup_link_auto_detach(pl->link); 130 kfree(pl); 131 static_branch_dec(&cgroup_bpf_enabled_key[atype]); 132 } 133 old_array = rcu_dereference_protected( 134 cgrp->bpf.effective[atype], 135 lockdep_is_held(&cgroup_mutex)); 136 bpf_prog_array_free(old_array); 137 } 138 139 list_for_each_entry_safe(storage, stmp, storages, list_cg) { 140 bpf_cgroup_storage_unlink(storage); 141 bpf_cgroup_storage_free(storage); 142 } 143 144 mutex_unlock(&cgroup_mutex); 145 146 for (p = cgroup_parent(cgrp); p; p = cgroup_parent(p)) 147 cgroup_bpf_put(p); 148 149 percpu_ref_exit(&cgrp->bpf.refcnt); 150 cgroup_put(cgrp); 151 } 152 153 /** 154 * cgroup_bpf_release_fn() - callback used to schedule releasing 155 * of bpf cgroup data 156 * @ref: percpu ref counter structure 157 */ 158 static void cgroup_bpf_release_fn(struct percpu_ref *ref) 159 { 160 struct cgroup *cgrp = container_of(ref, struct cgroup, bpf.refcnt); 161 162 INIT_WORK(&cgrp->bpf.release_work, cgroup_bpf_release); 163 queue_work(system_wq, &cgrp->bpf.release_work); 164 } 165 166 /* Get underlying bpf_prog of bpf_prog_list entry, regardless if it's through 167 * link or direct prog. 168 */ 169 static struct bpf_prog *prog_list_prog(struct bpf_prog_list *pl) 170 { 171 if (pl->prog) 172 return pl->prog; 173 if (pl->link) 174 return pl->link->link.prog; 175 return NULL; 176 } 177 178 /* count number of elements in the list. 179 * it's slow but the list cannot be long 180 */ 181 static u32 prog_list_length(struct list_head *head) 182 { 183 struct bpf_prog_list *pl; 184 u32 cnt = 0; 185 186 list_for_each_entry(pl, head, node) { 187 if (!prog_list_prog(pl)) 188 continue; 189 cnt++; 190 } 191 return cnt; 192 } 193 194 /* if parent has non-overridable prog attached, 195 * disallow attaching new programs to the descendent cgroup. 196 * if parent has overridable or multi-prog, allow attaching 197 */ 198 static bool hierarchy_allows_attach(struct cgroup *cgrp, 199 enum cgroup_bpf_attach_type atype) 200 { 201 struct cgroup *p; 202 203 p = cgroup_parent(cgrp); 204 if (!p) 205 return true; 206 do { 207 u32 flags = p->bpf.flags[atype]; 208 u32 cnt; 209 210 if (flags & BPF_F_ALLOW_MULTI) 211 return true; 212 cnt = prog_list_length(&p->bpf.progs[atype]); 213 WARN_ON_ONCE(cnt > 1); 214 if (cnt == 1) 215 return !!(flags & BPF_F_ALLOW_OVERRIDE); 216 p = cgroup_parent(p); 217 } while (p); 218 return true; 219 } 220 221 /* compute a chain of effective programs for a given cgroup: 222 * start from the list of programs in this cgroup and add 223 * all parent programs. 224 * Note that parent's F_ALLOW_OVERRIDE-type program is yielding 225 * to programs in this cgroup 226 */ 227 static int compute_effective_progs(struct cgroup *cgrp, 228 enum cgroup_bpf_attach_type atype, 229 struct bpf_prog_array **array) 230 { 231 struct bpf_prog_array_item *item; 232 struct bpf_prog_array *progs; 233 struct bpf_prog_list *pl; 234 struct cgroup *p = cgrp; 235 int cnt = 0; 236 237 /* count number of effective programs by walking parents */ 238 do { 239 if (cnt == 0 || (p->bpf.flags[atype] & BPF_F_ALLOW_MULTI)) 240 cnt += prog_list_length(&p->bpf.progs[atype]); 241 p = cgroup_parent(p); 242 } while (p); 243 244 progs = bpf_prog_array_alloc(cnt, GFP_KERNEL); 245 if (!progs) 246 return -ENOMEM; 247 248 /* populate the array with effective progs */ 249 cnt = 0; 250 p = cgrp; 251 do { 252 if (cnt > 0 && !(p->bpf.flags[atype] & BPF_F_ALLOW_MULTI)) 253 continue; 254 255 list_for_each_entry(pl, &p->bpf.progs[atype], node) { 256 if (!prog_list_prog(pl)) 257 continue; 258 259 item = &progs->items[cnt]; 260 item->prog = prog_list_prog(pl); 261 bpf_cgroup_storages_assign(item->cgroup_storage, 262 pl->storage); 263 cnt++; 264 } 265 } while ((p = cgroup_parent(p))); 266 267 *array = progs; 268 return 0; 269 } 270 271 static void activate_effective_progs(struct cgroup *cgrp, 272 enum cgroup_bpf_attach_type atype, 273 struct bpf_prog_array *old_array) 274 { 275 old_array = rcu_replace_pointer(cgrp->bpf.effective[atype], old_array, 276 lockdep_is_held(&cgroup_mutex)); 277 /* free prog array after grace period, since __cgroup_bpf_run_*() 278 * might be still walking the array 279 */ 280 bpf_prog_array_free(old_array); 281 } 282 283 /** 284 * cgroup_bpf_inherit() - inherit effective programs from parent 285 * @cgrp: the cgroup to modify 286 */ 287 int cgroup_bpf_inherit(struct cgroup *cgrp) 288 { 289 /* has to use marco instead of const int, since compiler thinks 290 * that array below is variable length 291 */ 292 #define NR ARRAY_SIZE(cgrp->bpf.effective) 293 struct bpf_prog_array *arrays[NR] = {}; 294 struct cgroup *p; 295 int ret, i; 296 297 ret = percpu_ref_init(&cgrp->bpf.refcnt, cgroup_bpf_release_fn, 0, 298 GFP_KERNEL); 299 if (ret) 300 return ret; 301 302 for (p = cgroup_parent(cgrp); p; p = cgroup_parent(p)) 303 cgroup_bpf_get(p); 304 305 for (i = 0; i < NR; i++) 306 INIT_LIST_HEAD(&cgrp->bpf.progs[i]); 307 308 INIT_LIST_HEAD(&cgrp->bpf.storages); 309 310 for (i = 0; i < NR; i++) 311 if (compute_effective_progs(cgrp, i, &arrays[i])) 312 goto cleanup; 313 314 for (i = 0; i < NR; i++) 315 activate_effective_progs(cgrp, i, arrays[i]); 316 317 return 0; 318 cleanup: 319 for (i = 0; i < NR; i++) 320 bpf_prog_array_free(arrays[i]); 321 322 for (p = cgroup_parent(cgrp); p; p = cgroup_parent(p)) 323 cgroup_bpf_put(p); 324 325 percpu_ref_exit(&cgrp->bpf.refcnt); 326 327 return -ENOMEM; 328 } 329 330 static int update_effective_progs(struct cgroup *cgrp, 331 enum cgroup_bpf_attach_type atype) 332 { 333 struct cgroup_subsys_state *css; 334 int err; 335 336 /* allocate and recompute effective prog arrays */ 337 css_for_each_descendant_pre(css, &cgrp->self) { 338 struct cgroup *desc = container_of(css, struct cgroup, self); 339 340 if (percpu_ref_is_zero(&desc->bpf.refcnt)) 341 continue; 342 343 err = compute_effective_progs(desc, atype, &desc->bpf.inactive); 344 if (err) 345 goto cleanup; 346 } 347 348 /* all allocations were successful. Activate all prog arrays */ 349 css_for_each_descendant_pre(css, &cgrp->self) { 350 struct cgroup *desc = container_of(css, struct cgroup, self); 351 352 if (percpu_ref_is_zero(&desc->bpf.refcnt)) { 353 if (unlikely(desc->bpf.inactive)) { 354 bpf_prog_array_free(desc->bpf.inactive); 355 desc->bpf.inactive = NULL; 356 } 357 continue; 358 } 359 360 activate_effective_progs(desc, atype, desc->bpf.inactive); 361 desc->bpf.inactive = NULL; 362 } 363 364 return 0; 365 366 cleanup: 367 /* oom while computing effective. Free all computed effective arrays 368 * since they were not activated 369 */ 370 css_for_each_descendant_pre(css, &cgrp->self) { 371 struct cgroup *desc = container_of(css, struct cgroup, self); 372 373 bpf_prog_array_free(desc->bpf.inactive); 374 desc->bpf.inactive = NULL; 375 } 376 377 return err; 378 } 379 380 #define BPF_CGROUP_MAX_PROGS 64 381 382 static struct bpf_prog_list *find_attach_entry(struct list_head *progs, 383 struct bpf_prog *prog, 384 struct bpf_cgroup_link *link, 385 struct bpf_prog *replace_prog, 386 bool allow_multi) 387 { 388 struct bpf_prog_list *pl; 389 390 /* single-attach case */ 391 if (!allow_multi) { 392 if (list_empty(progs)) 393 return NULL; 394 return list_first_entry(progs, typeof(*pl), node); 395 } 396 397 list_for_each_entry(pl, progs, node) { 398 if (prog && pl->prog == prog && prog != replace_prog) 399 /* disallow attaching the same prog twice */ 400 return ERR_PTR(-EINVAL); 401 if (link && pl->link == link) 402 /* disallow attaching the same link twice */ 403 return ERR_PTR(-EINVAL); 404 } 405 406 /* direct prog multi-attach w/ replacement case */ 407 if (replace_prog) { 408 list_for_each_entry(pl, progs, node) { 409 if (pl->prog == replace_prog) 410 /* a match found */ 411 return pl; 412 } 413 /* prog to replace not found for cgroup */ 414 return ERR_PTR(-ENOENT); 415 } 416 417 return NULL; 418 } 419 420 /** 421 * __cgroup_bpf_attach() - Attach the program or the link to a cgroup, and 422 * propagate the change to descendants 423 * @cgrp: The cgroup which descendants to traverse 424 * @prog: A program to attach 425 * @link: A link to attach 426 * @replace_prog: Previously attached program to replace if BPF_F_REPLACE is set 427 * @type: Type of attach operation 428 * @flags: Option flags 429 * 430 * Exactly one of @prog or @link can be non-null. 431 * Must be called with cgroup_mutex held. 432 */ 433 int __cgroup_bpf_attach(struct cgroup *cgrp, 434 struct bpf_prog *prog, struct bpf_prog *replace_prog, 435 struct bpf_cgroup_link *link, 436 enum bpf_attach_type type, u32 flags) 437 { 438 u32 saved_flags = (flags & (BPF_F_ALLOW_OVERRIDE | BPF_F_ALLOW_MULTI)); 439 struct bpf_prog *old_prog = NULL; 440 struct bpf_cgroup_storage *storage[MAX_BPF_CGROUP_STORAGE_TYPE] = {}; 441 struct bpf_cgroup_storage *new_storage[MAX_BPF_CGROUP_STORAGE_TYPE] = {}; 442 enum cgroup_bpf_attach_type atype; 443 struct bpf_prog_list *pl; 444 struct list_head *progs; 445 int err; 446 447 if (((flags & BPF_F_ALLOW_OVERRIDE) && (flags & BPF_F_ALLOW_MULTI)) || 448 ((flags & BPF_F_REPLACE) && !(flags & BPF_F_ALLOW_MULTI))) 449 /* invalid combination */ 450 return -EINVAL; 451 if (link && (prog || replace_prog)) 452 /* only either link or prog/replace_prog can be specified */ 453 return -EINVAL; 454 if (!!replace_prog != !!(flags & BPF_F_REPLACE)) 455 /* replace_prog implies BPF_F_REPLACE, and vice versa */ 456 return -EINVAL; 457 458 atype = to_cgroup_bpf_attach_type(type); 459 if (atype < 0) 460 return -EINVAL; 461 462 progs = &cgrp->bpf.progs[atype]; 463 464 if (!hierarchy_allows_attach(cgrp, atype)) 465 return -EPERM; 466 467 if (!list_empty(progs) && cgrp->bpf.flags[atype] != saved_flags) 468 /* Disallow attaching non-overridable on top 469 * of existing overridable in this cgroup. 470 * Disallow attaching multi-prog if overridable or none 471 */ 472 return -EPERM; 473 474 if (prog_list_length(progs) >= BPF_CGROUP_MAX_PROGS) 475 return -E2BIG; 476 477 pl = find_attach_entry(progs, prog, link, replace_prog, 478 flags & BPF_F_ALLOW_MULTI); 479 if (IS_ERR(pl)) 480 return PTR_ERR(pl); 481 482 if (bpf_cgroup_storages_alloc(storage, new_storage, type, 483 prog ? : link->link.prog, cgrp)) 484 return -ENOMEM; 485 486 if (pl) { 487 old_prog = pl->prog; 488 } else { 489 pl = kmalloc(sizeof(*pl), GFP_KERNEL); 490 if (!pl) { 491 bpf_cgroup_storages_free(new_storage); 492 return -ENOMEM; 493 } 494 list_add_tail(&pl->node, progs); 495 } 496 497 pl->prog = prog; 498 pl->link = link; 499 bpf_cgroup_storages_assign(pl->storage, storage); 500 cgrp->bpf.flags[atype] = saved_flags; 501 502 err = update_effective_progs(cgrp, atype); 503 if (err) 504 goto cleanup; 505 506 if (old_prog) 507 bpf_prog_put(old_prog); 508 else 509 static_branch_inc(&cgroup_bpf_enabled_key[atype]); 510 bpf_cgroup_storages_link(new_storage, cgrp, type); 511 return 0; 512 513 cleanup: 514 if (old_prog) { 515 pl->prog = old_prog; 516 pl->link = NULL; 517 } 518 bpf_cgroup_storages_free(new_storage); 519 if (!old_prog) { 520 list_del(&pl->node); 521 kfree(pl); 522 } 523 return err; 524 } 525 526 /* Swap updated BPF program for given link in effective program arrays across 527 * all descendant cgroups. This function is guaranteed to succeed. 528 */ 529 static void replace_effective_prog(struct cgroup *cgrp, 530 enum cgroup_bpf_attach_type atype, 531 struct bpf_cgroup_link *link) 532 { 533 struct bpf_prog_array_item *item; 534 struct cgroup_subsys_state *css; 535 struct bpf_prog_array *progs; 536 struct bpf_prog_list *pl; 537 struct list_head *head; 538 struct cgroup *cg; 539 int pos; 540 541 css_for_each_descendant_pre(css, &cgrp->self) { 542 struct cgroup *desc = container_of(css, struct cgroup, self); 543 544 if (percpu_ref_is_zero(&desc->bpf.refcnt)) 545 continue; 546 547 /* find position of link in effective progs array */ 548 for (pos = 0, cg = desc; cg; cg = cgroup_parent(cg)) { 549 if (pos && !(cg->bpf.flags[atype] & BPF_F_ALLOW_MULTI)) 550 continue; 551 552 head = &cg->bpf.progs[atype]; 553 list_for_each_entry(pl, head, node) { 554 if (!prog_list_prog(pl)) 555 continue; 556 if (pl->link == link) 557 goto found; 558 pos++; 559 } 560 } 561 found: 562 BUG_ON(!cg); 563 progs = rcu_dereference_protected( 564 desc->bpf.effective[atype], 565 lockdep_is_held(&cgroup_mutex)); 566 item = &progs->items[pos]; 567 WRITE_ONCE(item->prog, link->link.prog); 568 } 569 } 570 571 /** 572 * __cgroup_bpf_replace() - Replace link's program and propagate the change 573 * to descendants 574 * @cgrp: The cgroup which descendants to traverse 575 * @link: A link for which to replace BPF program 576 * @type: Type of attach operation 577 * 578 * Must be called with cgroup_mutex held. 579 */ 580 static int __cgroup_bpf_replace(struct cgroup *cgrp, 581 struct bpf_cgroup_link *link, 582 struct bpf_prog *new_prog) 583 { 584 enum cgroup_bpf_attach_type atype; 585 struct bpf_prog *old_prog; 586 struct bpf_prog_list *pl; 587 struct list_head *progs; 588 bool found = false; 589 590 atype = to_cgroup_bpf_attach_type(link->type); 591 if (atype < 0) 592 return -EINVAL; 593 594 progs = &cgrp->bpf.progs[atype]; 595 596 if (link->link.prog->type != new_prog->type) 597 return -EINVAL; 598 599 list_for_each_entry(pl, progs, node) { 600 if (pl->link == link) { 601 found = true; 602 break; 603 } 604 } 605 if (!found) 606 return -ENOENT; 607 608 old_prog = xchg(&link->link.prog, new_prog); 609 replace_effective_prog(cgrp, atype, link); 610 bpf_prog_put(old_prog); 611 return 0; 612 } 613 614 static int cgroup_bpf_replace(struct bpf_link *link, struct bpf_prog *new_prog, 615 struct bpf_prog *old_prog) 616 { 617 struct bpf_cgroup_link *cg_link; 618 int ret; 619 620 cg_link = container_of(link, struct bpf_cgroup_link, link); 621 622 mutex_lock(&cgroup_mutex); 623 /* link might have been auto-released by dying cgroup, so fail */ 624 if (!cg_link->cgroup) { 625 ret = -ENOLINK; 626 goto out_unlock; 627 } 628 if (old_prog && link->prog != old_prog) { 629 ret = -EPERM; 630 goto out_unlock; 631 } 632 ret = __cgroup_bpf_replace(cg_link->cgroup, cg_link, new_prog); 633 out_unlock: 634 mutex_unlock(&cgroup_mutex); 635 return ret; 636 } 637 638 static struct bpf_prog_list *find_detach_entry(struct list_head *progs, 639 struct bpf_prog *prog, 640 struct bpf_cgroup_link *link, 641 bool allow_multi) 642 { 643 struct bpf_prog_list *pl; 644 645 if (!allow_multi) { 646 if (list_empty(progs)) 647 /* report error when trying to detach and nothing is attached */ 648 return ERR_PTR(-ENOENT); 649 650 /* to maintain backward compatibility NONE and OVERRIDE cgroups 651 * allow detaching with invalid FD (prog==NULL) in legacy mode 652 */ 653 return list_first_entry(progs, typeof(*pl), node); 654 } 655 656 if (!prog && !link) 657 /* to detach MULTI prog the user has to specify valid FD 658 * of the program or link to be detached 659 */ 660 return ERR_PTR(-EINVAL); 661 662 /* find the prog or link and detach it */ 663 list_for_each_entry(pl, progs, node) { 664 if (pl->prog == prog && pl->link == link) 665 return pl; 666 } 667 return ERR_PTR(-ENOENT); 668 } 669 670 /** 671 * __cgroup_bpf_detach() - Detach the program or link from a cgroup, and 672 * propagate the change to descendants 673 * @cgrp: The cgroup which descendants to traverse 674 * @prog: A program to detach or NULL 675 * @prog: A link to detach or NULL 676 * @type: Type of detach operation 677 * 678 * At most one of @prog or @link can be non-NULL. 679 * Must be called with cgroup_mutex held. 680 */ 681 int __cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog, 682 struct bpf_cgroup_link *link, enum bpf_attach_type type) 683 { 684 enum cgroup_bpf_attach_type atype; 685 struct bpf_prog *old_prog; 686 struct bpf_prog_list *pl; 687 struct list_head *progs; 688 u32 flags; 689 int err; 690 691 atype = to_cgroup_bpf_attach_type(type); 692 if (atype < 0) 693 return -EINVAL; 694 695 progs = &cgrp->bpf.progs[atype]; 696 flags = cgrp->bpf.flags[atype]; 697 698 if (prog && link) 699 /* only one of prog or link can be specified */ 700 return -EINVAL; 701 702 pl = find_detach_entry(progs, prog, link, flags & BPF_F_ALLOW_MULTI); 703 if (IS_ERR(pl)) 704 return PTR_ERR(pl); 705 706 /* mark it deleted, so it's ignored while recomputing effective */ 707 old_prog = pl->prog; 708 pl->prog = NULL; 709 pl->link = NULL; 710 711 err = update_effective_progs(cgrp, atype); 712 if (err) 713 goto cleanup; 714 715 /* now can actually delete it from this cgroup list */ 716 list_del(&pl->node); 717 kfree(pl); 718 if (list_empty(progs)) 719 /* last program was detached, reset flags to zero */ 720 cgrp->bpf.flags[atype] = 0; 721 if (old_prog) 722 bpf_prog_put(old_prog); 723 static_branch_dec(&cgroup_bpf_enabled_key[atype]); 724 return 0; 725 726 cleanup: 727 /* restore back prog or link */ 728 pl->prog = old_prog; 729 pl->link = link; 730 return err; 731 } 732 733 /* Must be called with cgroup_mutex held to avoid races. */ 734 int __cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr, 735 union bpf_attr __user *uattr) 736 { 737 __u32 __user *prog_ids = u64_to_user_ptr(attr->query.prog_ids); 738 enum bpf_attach_type type = attr->query.attach_type; 739 enum cgroup_bpf_attach_type atype; 740 struct bpf_prog_array *effective; 741 struct list_head *progs; 742 struct bpf_prog *prog; 743 int cnt, ret = 0, i; 744 u32 flags; 745 746 atype = to_cgroup_bpf_attach_type(type); 747 if (atype < 0) 748 return -EINVAL; 749 750 progs = &cgrp->bpf.progs[atype]; 751 flags = cgrp->bpf.flags[atype]; 752 753 effective = rcu_dereference_protected(cgrp->bpf.effective[atype], 754 lockdep_is_held(&cgroup_mutex)); 755 756 if (attr->query.query_flags & BPF_F_QUERY_EFFECTIVE) 757 cnt = bpf_prog_array_length(effective); 758 else 759 cnt = prog_list_length(progs); 760 761 if (copy_to_user(&uattr->query.attach_flags, &flags, sizeof(flags))) 762 return -EFAULT; 763 if (copy_to_user(&uattr->query.prog_cnt, &cnt, sizeof(cnt))) 764 return -EFAULT; 765 if (attr->query.prog_cnt == 0 || !prog_ids || !cnt) 766 /* return early if user requested only program count + flags */ 767 return 0; 768 if (attr->query.prog_cnt < cnt) { 769 cnt = attr->query.prog_cnt; 770 ret = -ENOSPC; 771 } 772 773 if (attr->query.query_flags & BPF_F_QUERY_EFFECTIVE) { 774 return bpf_prog_array_copy_to_user(effective, prog_ids, cnt); 775 } else { 776 struct bpf_prog_list *pl; 777 u32 id; 778 779 i = 0; 780 list_for_each_entry(pl, progs, node) { 781 prog = prog_list_prog(pl); 782 id = prog->aux->id; 783 if (copy_to_user(prog_ids + i, &id, sizeof(id))) 784 return -EFAULT; 785 if (++i == cnt) 786 break; 787 } 788 } 789 return ret; 790 } 791 792 int cgroup_bpf_prog_attach(const union bpf_attr *attr, 793 enum bpf_prog_type ptype, struct bpf_prog *prog) 794 { 795 struct bpf_prog *replace_prog = NULL; 796 struct cgroup *cgrp; 797 int ret; 798 799 cgrp = cgroup_get_from_fd(attr->target_fd); 800 if (IS_ERR(cgrp)) 801 return PTR_ERR(cgrp); 802 803 if ((attr->attach_flags & BPF_F_ALLOW_MULTI) && 804 (attr->attach_flags & BPF_F_REPLACE)) { 805 replace_prog = bpf_prog_get_type(attr->replace_bpf_fd, ptype); 806 if (IS_ERR(replace_prog)) { 807 cgroup_put(cgrp); 808 return PTR_ERR(replace_prog); 809 } 810 } 811 812 ret = cgroup_bpf_attach(cgrp, prog, replace_prog, NULL, 813 attr->attach_type, attr->attach_flags); 814 815 if (replace_prog) 816 bpf_prog_put(replace_prog); 817 cgroup_put(cgrp); 818 return ret; 819 } 820 821 int cgroup_bpf_prog_detach(const union bpf_attr *attr, enum bpf_prog_type ptype) 822 { 823 struct bpf_prog *prog; 824 struct cgroup *cgrp; 825 int ret; 826 827 cgrp = cgroup_get_from_fd(attr->target_fd); 828 if (IS_ERR(cgrp)) 829 return PTR_ERR(cgrp); 830 831 prog = bpf_prog_get_type(attr->attach_bpf_fd, ptype); 832 if (IS_ERR(prog)) 833 prog = NULL; 834 835 ret = cgroup_bpf_detach(cgrp, prog, attr->attach_type); 836 if (prog) 837 bpf_prog_put(prog); 838 839 cgroup_put(cgrp); 840 return ret; 841 } 842 843 static void bpf_cgroup_link_release(struct bpf_link *link) 844 { 845 struct bpf_cgroup_link *cg_link = 846 container_of(link, struct bpf_cgroup_link, link); 847 struct cgroup *cg; 848 849 /* link might have been auto-detached by dying cgroup already, 850 * in that case our work is done here 851 */ 852 if (!cg_link->cgroup) 853 return; 854 855 mutex_lock(&cgroup_mutex); 856 857 /* re-check cgroup under lock again */ 858 if (!cg_link->cgroup) { 859 mutex_unlock(&cgroup_mutex); 860 return; 861 } 862 863 WARN_ON(__cgroup_bpf_detach(cg_link->cgroup, NULL, cg_link, 864 cg_link->type)); 865 866 cg = cg_link->cgroup; 867 cg_link->cgroup = NULL; 868 869 mutex_unlock(&cgroup_mutex); 870 871 cgroup_put(cg); 872 } 873 874 static void bpf_cgroup_link_dealloc(struct bpf_link *link) 875 { 876 struct bpf_cgroup_link *cg_link = 877 container_of(link, struct bpf_cgroup_link, link); 878 879 kfree(cg_link); 880 } 881 882 static int bpf_cgroup_link_detach(struct bpf_link *link) 883 { 884 bpf_cgroup_link_release(link); 885 886 return 0; 887 } 888 889 static void bpf_cgroup_link_show_fdinfo(const struct bpf_link *link, 890 struct seq_file *seq) 891 { 892 struct bpf_cgroup_link *cg_link = 893 container_of(link, struct bpf_cgroup_link, link); 894 u64 cg_id = 0; 895 896 mutex_lock(&cgroup_mutex); 897 if (cg_link->cgroup) 898 cg_id = cgroup_id(cg_link->cgroup); 899 mutex_unlock(&cgroup_mutex); 900 901 seq_printf(seq, 902 "cgroup_id:\t%llu\n" 903 "attach_type:\t%d\n", 904 cg_id, 905 cg_link->type); 906 } 907 908 static int bpf_cgroup_link_fill_link_info(const struct bpf_link *link, 909 struct bpf_link_info *info) 910 { 911 struct bpf_cgroup_link *cg_link = 912 container_of(link, struct bpf_cgroup_link, link); 913 u64 cg_id = 0; 914 915 mutex_lock(&cgroup_mutex); 916 if (cg_link->cgroup) 917 cg_id = cgroup_id(cg_link->cgroup); 918 mutex_unlock(&cgroup_mutex); 919 920 info->cgroup.cgroup_id = cg_id; 921 info->cgroup.attach_type = cg_link->type; 922 return 0; 923 } 924 925 static const struct bpf_link_ops bpf_cgroup_link_lops = { 926 .release = bpf_cgroup_link_release, 927 .dealloc = bpf_cgroup_link_dealloc, 928 .detach = bpf_cgroup_link_detach, 929 .update_prog = cgroup_bpf_replace, 930 .show_fdinfo = bpf_cgroup_link_show_fdinfo, 931 .fill_link_info = bpf_cgroup_link_fill_link_info, 932 }; 933 934 int cgroup_bpf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) 935 { 936 struct bpf_link_primer link_primer; 937 struct bpf_cgroup_link *link; 938 struct cgroup *cgrp; 939 int err; 940 941 if (attr->link_create.flags) 942 return -EINVAL; 943 944 cgrp = cgroup_get_from_fd(attr->link_create.target_fd); 945 if (IS_ERR(cgrp)) 946 return PTR_ERR(cgrp); 947 948 link = kzalloc(sizeof(*link), GFP_USER); 949 if (!link) { 950 err = -ENOMEM; 951 goto out_put_cgroup; 952 } 953 bpf_link_init(&link->link, BPF_LINK_TYPE_CGROUP, &bpf_cgroup_link_lops, 954 prog); 955 link->cgroup = cgrp; 956 link->type = attr->link_create.attach_type; 957 958 err = bpf_link_prime(&link->link, &link_primer); 959 if (err) { 960 kfree(link); 961 goto out_put_cgroup; 962 } 963 964 err = cgroup_bpf_attach(cgrp, NULL, NULL, link, 965 link->type, BPF_F_ALLOW_MULTI); 966 if (err) { 967 bpf_link_cleanup(&link_primer); 968 goto out_put_cgroup; 969 } 970 971 return bpf_link_settle(&link_primer); 972 973 out_put_cgroup: 974 cgroup_put(cgrp); 975 return err; 976 } 977 978 int cgroup_bpf_prog_query(const union bpf_attr *attr, 979 union bpf_attr __user *uattr) 980 { 981 struct cgroup *cgrp; 982 int ret; 983 984 cgrp = cgroup_get_from_fd(attr->query.target_fd); 985 if (IS_ERR(cgrp)) 986 return PTR_ERR(cgrp); 987 988 ret = cgroup_bpf_query(cgrp, attr, uattr); 989 990 cgroup_put(cgrp); 991 return ret; 992 } 993 994 /** 995 * __cgroup_bpf_run_filter_skb() - Run a program for packet filtering 996 * @sk: The socket sending or receiving traffic 997 * @skb: The skb that is being sent or received 998 * @type: The type of program to be exectuted 999 * 1000 * If no socket is passed, or the socket is not of type INET or INET6, 1001 * this function does nothing and returns 0. 1002 * 1003 * The program type passed in via @type must be suitable for network 1004 * filtering. No further check is performed to assert that. 1005 * 1006 * For egress packets, this function can return: 1007 * NET_XMIT_SUCCESS (0) - continue with packet output 1008 * NET_XMIT_DROP (1) - drop packet and notify TCP to call cwr 1009 * NET_XMIT_CN (2) - continue with packet output and notify TCP 1010 * to call cwr 1011 * -EPERM - drop packet 1012 * 1013 * For ingress packets, this function will return -EPERM if any 1014 * attached program was found and if it returned != 1 during execution. 1015 * Otherwise 0 is returned. 1016 */ 1017 int __cgroup_bpf_run_filter_skb(struct sock *sk, 1018 struct sk_buff *skb, 1019 enum cgroup_bpf_attach_type atype) 1020 { 1021 unsigned int offset = skb->data - skb_network_header(skb); 1022 struct sock *save_sk; 1023 void *saved_data_end; 1024 struct cgroup *cgrp; 1025 int ret; 1026 1027 if (!sk || !sk_fullsock(sk)) 1028 return 0; 1029 1030 if (sk->sk_family != AF_INET && sk->sk_family != AF_INET6) 1031 return 0; 1032 1033 cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data); 1034 save_sk = skb->sk; 1035 skb->sk = sk; 1036 __skb_push(skb, offset); 1037 1038 /* compute pointers for the bpf prog */ 1039 bpf_compute_and_save_data_end(skb, &saved_data_end); 1040 1041 if (atype == CGROUP_INET_EGRESS) { 1042 ret = BPF_PROG_CGROUP_INET_EGRESS_RUN_ARRAY( 1043 cgrp->bpf.effective[atype], skb, __bpf_prog_run_save_cb); 1044 } else { 1045 ret = BPF_PROG_RUN_ARRAY_CG(cgrp->bpf.effective[atype], skb, 1046 __bpf_prog_run_save_cb); 1047 ret = (ret == 1 ? 0 : -EPERM); 1048 } 1049 bpf_restore_data_end(skb, saved_data_end); 1050 __skb_pull(skb, offset); 1051 skb->sk = save_sk; 1052 1053 return ret; 1054 } 1055 EXPORT_SYMBOL(__cgroup_bpf_run_filter_skb); 1056 1057 /** 1058 * __cgroup_bpf_run_filter_sk() - Run a program on a sock 1059 * @sk: sock structure to manipulate 1060 * @type: The type of program to be exectuted 1061 * 1062 * socket is passed is expected to be of type INET or INET6. 1063 * 1064 * The program type passed in via @type must be suitable for sock 1065 * filtering. No further check is performed to assert that. 1066 * 1067 * This function will return %-EPERM if any if an attached program was found 1068 * and if it returned != 1 during execution. In all other cases, 0 is returned. 1069 */ 1070 int __cgroup_bpf_run_filter_sk(struct sock *sk, 1071 enum cgroup_bpf_attach_type atype) 1072 { 1073 struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data); 1074 int ret; 1075 1076 ret = BPF_PROG_RUN_ARRAY_CG(cgrp->bpf.effective[atype], sk, bpf_prog_run); 1077 return ret == 1 ? 0 : -EPERM; 1078 } 1079 EXPORT_SYMBOL(__cgroup_bpf_run_filter_sk); 1080 1081 /** 1082 * __cgroup_bpf_run_filter_sock_addr() - Run a program on a sock and 1083 * provided by user sockaddr 1084 * @sk: sock struct that will use sockaddr 1085 * @uaddr: sockaddr struct provided by user 1086 * @type: The type of program to be exectuted 1087 * @t_ctx: Pointer to attach type specific context 1088 * @flags: Pointer to u32 which contains higher bits of BPF program 1089 * return value (OR'ed together). 1090 * 1091 * socket is expected to be of type INET or INET6. 1092 * 1093 * This function will return %-EPERM if an attached program is found and 1094 * returned value != 1 during execution. In all other cases, 0 is returned. 1095 */ 1096 int __cgroup_bpf_run_filter_sock_addr(struct sock *sk, 1097 struct sockaddr *uaddr, 1098 enum cgroup_bpf_attach_type atype, 1099 void *t_ctx, 1100 u32 *flags) 1101 { 1102 struct bpf_sock_addr_kern ctx = { 1103 .sk = sk, 1104 .uaddr = uaddr, 1105 .t_ctx = t_ctx, 1106 }; 1107 struct sockaddr_storage unspec; 1108 struct cgroup *cgrp; 1109 int ret; 1110 1111 /* Check socket family since not all sockets represent network 1112 * endpoint (e.g. AF_UNIX). 1113 */ 1114 if (sk->sk_family != AF_INET && sk->sk_family != AF_INET6) 1115 return 0; 1116 1117 if (!ctx.uaddr) { 1118 memset(&unspec, 0, sizeof(unspec)); 1119 ctx.uaddr = (struct sockaddr *)&unspec; 1120 } 1121 1122 cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data); 1123 ret = BPF_PROG_RUN_ARRAY_CG_FLAGS(cgrp->bpf.effective[atype], &ctx, 1124 bpf_prog_run, flags); 1125 1126 return ret == 1 ? 0 : -EPERM; 1127 } 1128 EXPORT_SYMBOL(__cgroup_bpf_run_filter_sock_addr); 1129 1130 /** 1131 * __cgroup_bpf_run_filter_sock_ops() - Run a program on a sock 1132 * @sk: socket to get cgroup from 1133 * @sock_ops: bpf_sock_ops_kern struct to pass to program. Contains 1134 * sk with connection information (IP addresses, etc.) May not contain 1135 * cgroup info if it is a req sock. 1136 * @type: The type of program to be exectuted 1137 * 1138 * socket passed is expected to be of type INET or INET6. 1139 * 1140 * The program type passed in via @type must be suitable for sock_ops 1141 * filtering. No further check is performed to assert that. 1142 * 1143 * This function will return %-EPERM if any if an attached program was found 1144 * and if it returned != 1 during execution. In all other cases, 0 is returned. 1145 */ 1146 int __cgroup_bpf_run_filter_sock_ops(struct sock *sk, 1147 struct bpf_sock_ops_kern *sock_ops, 1148 enum cgroup_bpf_attach_type atype) 1149 { 1150 struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data); 1151 int ret; 1152 1153 ret = BPF_PROG_RUN_ARRAY_CG(cgrp->bpf.effective[atype], sock_ops, 1154 bpf_prog_run); 1155 return ret == 1 ? 0 : -EPERM; 1156 } 1157 EXPORT_SYMBOL(__cgroup_bpf_run_filter_sock_ops); 1158 1159 int __cgroup_bpf_check_dev_permission(short dev_type, u32 major, u32 minor, 1160 short access, enum cgroup_bpf_attach_type atype) 1161 { 1162 struct cgroup *cgrp; 1163 struct bpf_cgroup_dev_ctx ctx = { 1164 .access_type = (access << 16) | dev_type, 1165 .major = major, 1166 .minor = minor, 1167 }; 1168 int allow; 1169 1170 rcu_read_lock(); 1171 cgrp = task_dfl_cgroup(current); 1172 allow = BPF_PROG_RUN_ARRAY_CG(cgrp->bpf.effective[atype], &ctx, 1173 bpf_prog_run); 1174 rcu_read_unlock(); 1175 1176 return !allow; 1177 } 1178 1179 static const struct bpf_func_proto * 1180 cgroup_base_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 1181 { 1182 switch (func_id) { 1183 case BPF_FUNC_get_current_uid_gid: 1184 return &bpf_get_current_uid_gid_proto; 1185 case BPF_FUNC_get_local_storage: 1186 return &bpf_get_local_storage_proto; 1187 case BPF_FUNC_get_current_cgroup_id: 1188 return &bpf_get_current_cgroup_id_proto; 1189 case BPF_FUNC_perf_event_output: 1190 return &bpf_event_output_data_proto; 1191 default: 1192 return bpf_base_func_proto(func_id); 1193 } 1194 } 1195 1196 static const struct bpf_func_proto * 1197 cgroup_dev_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 1198 { 1199 return cgroup_base_func_proto(func_id, prog); 1200 } 1201 1202 static bool cgroup_dev_is_valid_access(int off, int size, 1203 enum bpf_access_type type, 1204 const struct bpf_prog *prog, 1205 struct bpf_insn_access_aux *info) 1206 { 1207 const int size_default = sizeof(__u32); 1208 1209 if (type == BPF_WRITE) 1210 return false; 1211 1212 if (off < 0 || off + size > sizeof(struct bpf_cgroup_dev_ctx)) 1213 return false; 1214 /* The verifier guarantees that size > 0. */ 1215 if (off % size != 0) 1216 return false; 1217 1218 switch (off) { 1219 case bpf_ctx_range(struct bpf_cgroup_dev_ctx, access_type): 1220 bpf_ctx_record_field_size(info, size_default); 1221 if (!bpf_ctx_narrow_access_ok(off, size, size_default)) 1222 return false; 1223 break; 1224 default: 1225 if (size != size_default) 1226 return false; 1227 } 1228 1229 return true; 1230 } 1231 1232 const struct bpf_prog_ops cg_dev_prog_ops = { 1233 }; 1234 1235 const struct bpf_verifier_ops cg_dev_verifier_ops = { 1236 .get_func_proto = cgroup_dev_func_proto, 1237 .is_valid_access = cgroup_dev_is_valid_access, 1238 }; 1239 1240 /** 1241 * __cgroup_bpf_run_filter_sysctl - Run a program on sysctl 1242 * 1243 * @head: sysctl table header 1244 * @table: sysctl table 1245 * @write: sysctl is being read (= 0) or written (= 1) 1246 * @buf: pointer to buffer (in and out) 1247 * @pcount: value-result argument: value is size of buffer pointed to by @buf, 1248 * result is size of @new_buf if program set new value, initial value 1249 * otherwise 1250 * @ppos: value-result argument: value is position at which read from or write 1251 * to sysctl is happening, result is new position if program overrode it, 1252 * initial value otherwise 1253 * @type: type of program to be executed 1254 * 1255 * Program is run when sysctl is being accessed, either read or written, and 1256 * can allow or deny such access. 1257 * 1258 * This function will return %-EPERM if an attached program is found and 1259 * returned value != 1 during execution. In all other cases 0 is returned. 1260 */ 1261 int __cgroup_bpf_run_filter_sysctl(struct ctl_table_header *head, 1262 struct ctl_table *table, int write, 1263 char **buf, size_t *pcount, loff_t *ppos, 1264 enum cgroup_bpf_attach_type atype) 1265 { 1266 struct bpf_sysctl_kern ctx = { 1267 .head = head, 1268 .table = table, 1269 .write = write, 1270 .ppos = ppos, 1271 .cur_val = NULL, 1272 .cur_len = PAGE_SIZE, 1273 .new_val = NULL, 1274 .new_len = 0, 1275 .new_updated = 0, 1276 }; 1277 struct cgroup *cgrp; 1278 loff_t pos = 0; 1279 int ret; 1280 1281 ctx.cur_val = kmalloc_track_caller(ctx.cur_len, GFP_KERNEL); 1282 if (!ctx.cur_val || 1283 table->proc_handler(table, 0, ctx.cur_val, &ctx.cur_len, &pos)) { 1284 /* Let BPF program decide how to proceed. */ 1285 ctx.cur_len = 0; 1286 } 1287 1288 if (write && *buf && *pcount) { 1289 /* BPF program should be able to override new value with a 1290 * buffer bigger than provided by user. 1291 */ 1292 ctx.new_val = kmalloc_track_caller(PAGE_SIZE, GFP_KERNEL); 1293 ctx.new_len = min_t(size_t, PAGE_SIZE, *pcount); 1294 if (ctx.new_val) { 1295 memcpy(ctx.new_val, *buf, ctx.new_len); 1296 } else { 1297 /* Let BPF program decide how to proceed. */ 1298 ctx.new_len = 0; 1299 } 1300 } 1301 1302 rcu_read_lock(); 1303 cgrp = task_dfl_cgroup(current); 1304 ret = BPF_PROG_RUN_ARRAY_CG(cgrp->bpf.effective[atype], &ctx, bpf_prog_run); 1305 rcu_read_unlock(); 1306 1307 kfree(ctx.cur_val); 1308 1309 if (ret == 1 && ctx.new_updated) { 1310 kfree(*buf); 1311 *buf = ctx.new_val; 1312 *pcount = ctx.new_len; 1313 } else { 1314 kfree(ctx.new_val); 1315 } 1316 1317 return ret == 1 ? 0 : -EPERM; 1318 } 1319 1320 #ifdef CONFIG_NET 1321 static bool __cgroup_bpf_prog_array_is_empty(struct cgroup *cgrp, 1322 enum cgroup_bpf_attach_type attach_type) 1323 { 1324 struct bpf_prog_array *prog_array; 1325 bool empty; 1326 1327 rcu_read_lock(); 1328 prog_array = rcu_dereference(cgrp->bpf.effective[attach_type]); 1329 empty = bpf_prog_array_is_empty(prog_array); 1330 rcu_read_unlock(); 1331 1332 return empty; 1333 } 1334 1335 static int sockopt_alloc_buf(struct bpf_sockopt_kern *ctx, int max_optlen, 1336 struct bpf_sockopt_buf *buf) 1337 { 1338 if (unlikely(max_optlen < 0)) 1339 return -EINVAL; 1340 1341 if (unlikely(max_optlen > PAGE_SIZE)) { 1342 /* We don't expose optvals that are greater than PAGE_SIZE 1343 * to the BPF program. 1344 */ 1345 max_optlen = PAGE_SIZE; 1346 } 1347 1348 if (max_optlen <= sizeof(buf->data)) { 1349 /* When the optval fits into BPF_SOCKOPT_KERN_BUF_SIZE 1350 * bytes avoid the cost of kzalloc. 1351 */ 1352 ctx->optval = buf->data; 1353 ctx->optval_end = ctx->optval + max_optlen; 1354 return max_optlen; 1355 } 1356 1357 ctx->optval = kzalloc(max_optlen, GFP_USER); 1358 if (!ctx->optval) 1359 return -ENOMEM; 1360 1361 ctx->optval_end = ctx->optval + max_optlen; 1362 1363 return max_optlen; 1364 } 1365 1366 static void sockopt_free_buf(struct bpf_sockopt_kern *ctx, 1367 struct bpf_sockopt_buf *buf) 1368 { 1369 if (ctx->optval == buf->data) 1370 return; 1371 kfree(ctx->optval); 1372 } 1373 1374 static bool sockopt_buf_allocated(struct bpf_sockopt_kern *ctx, 1375 struct bpf_sockopt_buf *buf) 1376 { 1377 return ctx->optval != buf->data; 1378 } 1379 1380 int __cgroup_bpf_run_filter_setsockopt(struct sock *sk, int *level, 1381 int *optname, char __user *optval, 1382 int *optlen, char **kernel_optval) 1383 { 1384 struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data); 1385 struct bpf_sockopt_buf buf = {}; 1386 struct bpf_sockopt_kern ctx = { 1387 .sk = sk, 1388 .level = *level, 1389 .optname = *optname, 1390 }; 1391 int ret, max_optlen; 1392 1393 /* Opportunistic check to see whether we have any BPF program 1394 * attached to the hook so we don't waste time allocating 1395 * memory and locking the socket. 1396 */ 1397 if (__cgroup_bpf_prog_array_is_empty(cgrp, CGROUP_SETSOCKOPT)) 1398 return 0; 1399 1400 /* Allocate a bit more than the initial user buffer for 1401 * BPF program. The canonical use case is overriding 1402 * TCP_CONGESTION(nv) to TCP_CONGESTION(cubic). 1403 */ 1404 max_optlen = max_t(int, 16, *optlen); 1405 1406 max_optlen = sockopt_alloc_buf(&ctx, max_optlen, &buf); 1407 if (max_optlen < 0) 1408 return max_optlen; 1409 1410 ctx.optlen = *optlen; 1411 1412 if (copy_from_user(ctx.optval, optval, min(*optlen, max_optlen)) != 0) { 1413 ret = -EFAULT; 1414 goto out; 1415 } 1416 1417 lock_sock(sk); 1418 ret = BPF_PROG_RUN_ARRAY_CG(cgrp->bpf.effective[CGROUP_SETSOCKOPT], 1419 &ctx, bpf_prog_run); 1420 release_sock(sk); 1421 1422 if (!ret) { 1423 ret = -EPERM; 1424 goto out; 1425 } 1426 1427 if (ctx.optlen == -1) { 1428 /* optlen set to -1, bypass kernel */ 1429 ret = 1; 1430 } else if (ctx.optlen > max_optlen || ctx.optlen < -1) { 1431 /* optlen is out of bounds */ 1432 ret = -EFAULT; 1433 } else { 1434 /* optlen within bounds, run kernel handler */ 1435 ret = 0; 1436 1437 /* export any potential modifications */ 1438 *level = ctx.level; 1439 *optname = ctx.optname; 1440 1441 /* optlen == 0 from BPF indicates that we should 1442 * use original userspace data. 1443 */ 1444 if (ctx.optlen != 0) { 1445 *optlen = ctx.optlen; 1446 /* We've used bpf_sockopt_kern->buf as an intermediary 1447 * storage, but the BPF program indicates that we need 1448 * to pass this data to the kernel setsockopt handler. 1449 * No way to export on-stack buf, have to allocate a 1450 * new buffer. 1451 */ 1452 if (!sockopt_buf_allocated(&ctx, &buf)) { 1453 void *p = kmalloc(ctx.optlen, GFP_USER); 1454 1455 if (!p) { 1456 ret = -ENOMEM; 1457 goto out; 1458 } 1459 memcpy(p, ctx.optval, ctx.optlen); 1460 *kernel_optval = p; 1461 } else { 1462 *kernel_optval = ctx.optval; 1463 } 1464 /* export and don't free sockopt buf */ 1465 return 0; 1466 } 1467 } 1468 1469 out: 1470 sockopt_free_buf(&ctx, &buf); 1471 return ret; 1472 } 1473 1474 int __cgroup_bpf_run_filter_getsockopt(struct sock *sk, int level, 1475 int optname, char __user *optval, 1476 int __user *optlen, int max_optlen, 1477 int retval) 1478 { 1479 struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data); 1480 struct bpf_sockopt_buf buf = {}; 1481 struct bpf_sockopt_kern ctx = { 1482 .sk = sk, 1483 .level = level, 1484 .optname = optname, 1485 .retval = retval, 1486 }; 1487 int ret; 1488 1489 /* Opportunistic check to see whether we have any BPF program 1490 * attached to the hook so we don't waste time allocating 1491 * memory and locking the socket. 1492 */ 1493 if (__cgroup_bpf_prog_array_is_empty(cgrp, CGROUP_GETSOCKOPT)) 1494 return retval; 1495 1496 ctx.optlen = max_optlen; 1497 1498 max_optlen = sockopt_alloc_buf(&ctx, max_optlen, &buf); 1499 if (max_optlen < 0) 1500 return max_optlen; 1501 1502 if (!retval) { 1503 /* If kernel getsockopt finished successfully, 1504 * copy whatever was returned to the user back 1505 * into our temporary buffer. Set optlen to the 1506 * one that kernel returned as well to let 1507 * BPF programs inspect the value. 1508 */ 1509 1510 if (get_user(ctx.optlen, optlen)) { 1511 ret = -EFAULT; 1512 goto out; 1513 } 1514 1515 if (ctx.optlen < 0) { 1516 ret = -EFAULT; 1517 goto out; 1518 } 1519 1520 if (copy_from_user(ctx.optval, optval, 1521 min(ctx.optlen, max_optlen)) != 0) { 1522 ret = -EFAULT; 1523 goto out; 1524 } 1525 } 1526 1527 lock_sock(sk); 1528 ret = BPF_PROG_RUN_ARRAY_CG(cgrp->bpf.effective[CGROUP_GETSOCKOPT], 1529 &ctx, bpf_prog_run); 1530 release_sock(sk); 1531 1532 if (!ret) { 1533 ret = -EPERM; 1534 goto out; 1535 } 1536 1537 if (ctx.optlen > max_optlen || ctx.optlen < 0) { 1538 ret = -EFAULT; 1539 goto out; 1540 } 1541 1542 /* BPF programs only allowed to set retval to 0, not some 1543 * arbitrary value. 1544 */ 1545 if (ctx.retval != 0 && ctx.retval != retval) { 1546 ret = -EFAULT; 1547 goto out; 1548 } 1549 1550 if (ctx.optlen != 0) { 1551 if (copy_to_user(optval, ctx.optval, ctx.optlen) || 1552 put_user(ctx.optlen, optlen)) { 1553 ret = -EFAULT; 1554 goto out; 1555 } 1556 } 1557 1558 ret = ctx.retval; 1559 1560 out: 1561 sockopt_free_buf(&ctx, &buf); 1562 return ret; 1563 } 1564 1565 int __cgroup_bpf_run_filter_getsockopt_kern(struct sock *sk, int level, 1566 int optname, void *optval, 1567 int *optlen, int retval) 1568 { 1569 struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data); 1570 struct bpf_sockopt_kern ctx = { 1571 .sk = sk, 1572 .level = level, 1573 .optname = optname, 1574 .retval = retval, 1575 .optlen = *optlen, 1576 .optval = optval, 1577 .optval_end = optval + *optlen, 1578 }; 1579 int ret; 1580 1581 /* Note that __cgroup_bpf_run_filter_getsockopt doesn't copy 1582 * user data back into BPF buffer when reval != 0. This is 1583 * done as an optimization to avoid extra copy, assuming 1584 * kernel won't populate the data in case of an error. 1585 * Here we always pass the data and memset() should 1586 * be called if that data shouldn't be "exported". 1587 */ 1588 1589 ret = BPF_PROG_RUN_ARRAY_CG(cgrp->bpf.effective[CGROUP_GETSOCKOPT], 1590 &ctx, bpf_prog_run); 1591 if (!ret) 1592 return -EPERM; 1593 1594 if (ctx.optlen > *optlen) 1595 return -EFAULT; 1596 1597 /* BPF programs only allowed to set retval to 0, not some 1598 * arbitrary value. 1599 */ 1600 if (ctx.retval != 0 && ctx.retval != retval) 1601 return -EFAULT; 1602 1603 /* BPF programs can shrink the buffer, export the modifications. 1604 */ 1605 if (ctx.optlen != 0) 1606 *optlen = ctx.optlen; 1607 1608 return ctx.retval; 1609 } 1610 #endif 1611 1612 static ssize_t sysctl_cpy_dir(const struct ctl_dir *dir, char **bufp, 1613 size_t *lenp) 1614 { 1615 ssize_t tmp_ret = 0, ret; 1616 1617 if (dir->header.parent) { 1618 tmp_ret = sysctl_cpy_dir(dir->header.parent, bufp, lenp); 1619 if (tmp_ret < 0) 1620 return tmp_ret; 1621 } 1622 1623 ret = strscpy(*bufp, dir->header.ctl_table[0].procname, *lenp); 1624 if (ret < 0) 1625 return ret; 1626 *bufp += ret; 1627 *lenp -= ret; 1628 ret += tmp_ret; 1629 1630 /* Avoid leading slash. */ 1631 if (!ret) 1632 return ret; 1633 1634 tmp_ret = strscpy(*bufp, "/", *lenp); 1635 if (tmp_ret < 0) 1636 return tmp_ret; 1637 *bufp += tmp_ret; 1638 *lenp -= tmp_ret; 1639 1640 return ret + tmp_ret; 1641 } 1642 1643 BPF_CALL_4(bpf_sysctl_get_name, struct bpf_sysctl_kern *, ctx, char *, buf, 1644 size_t, buf_len, u64, flags) 1645 { 1646 ssize_t tmp_ret = 0, ret; 1647 1648 if (!buf) 1649 return -EINVAL; 1650 1651 if (!(flags & BPF_F_SYSCTL_BASE_NAME)) { 1652 if (!ctx->head) 1653 return -EINVAL; 1654 tmp_ret = sysctl_cpy_dir(ctx->head->parent, &buf, &buf_len); 1655 if (tmp_ret < 0) 1656 return tmp_ret; 1657 } 1658 1659 ret = strscpy(buf, ctx->table->procname, buf_len); 1660 1661 return ret < 0 ? ret : tmp_ret + ret; 1662 } 1663 1664 static const struct bpf_func_proto bpf_sysctl_get_name_proto = { 1665 .func = bpf_sysctl_get_name, 1666 .gpl_only = false, 1667 .ret_type = RET_INTEGER, 1668 .arg1_type = ARG_PTR_TO_CTX, 1669 .arg2_type = ARG_PTR_TO_MEM, 1670 .arg3_type = ARG_CONST_SIZE, 1671 .arg4_type = ARG_ANYTHING, 1672 }; 1673 1674 static int copy_sysctl_value(char *dst, size_t dst_len, char *src, 1675 size_t src_len) 1676 { 1677 if (!dst) 1678 return -EINVAL; 1679 1680 if (!dst_len) 1681 return -E2BIG; 1682 1683 if (!src || !src_len) { 1684 memset(dst, 0, dst_len); 1685 return -EINVAL; 1686 } 1687 1688 memcpy(dst, src, min(dst_len, src_len)); 1689 1690 if (dst_len > src_len) { 1691 memset(dst + src_len, '\0', dst_len - src_len); 1692 return src_len; 1693 } 1694 1695 dst[dst_len - 1] = '\0'; 1696 1697 return -E2BIG; 1698 } 1699 1700 BPF_CALL_3(bpf_sysctl_get_current_value, struct bpf_sysctl_kern *, ctx, 1701 char *, buf, size_t, buf_len) 1702 { 1703 return copy_sysctl_value(buf, buf_len, ctx->cur_val, ctx->cur_len); 1704 } 1705 1706 static const struct bpf_func_proto bpf_sysctl_get_current_value_proto = { 1707 .func = bpf_sysctl_get_current_value, 1708 .gpl_only = false, 1709 .ret_type = RET_INTEGER, 1710 .arg1_type = ARG_PTR_TO_CTX, 1711 .arg2_type = ARG_PTR_TO_UNINIT_MEM, 1712 .arg3_type = ARG_CONST_SIZE, 1713 }; 1714 1715 BPF_CALL_3(bpf_sysctl_get_new_value, struct bpf_sysctl_kern *, ctx, char *, buf, 1716 size_t, buf_len) 1717 { 1718 if (!ctx->write) { 1719 if (buf && buf_len) 1720 memset(buf, '\0', buf_len); 1721 return -EINVAL; 1722 } 1723 return copy_sysctl_value(buf, buf_len, ctx->new_val, ctx->new_len); 1724 } 1725 1726 static const struct bpf_func_proto bpf_sysctl_get_new_value_proto = { 1727 .func = bpf_sysctl_get_new_value, 1728 .gpl_only = false, 1729 .ret_type = RET_INTEGER, 1730 .arg1_type = ARG_PTR_TO_CTX, 1731 .arg2_type = ARG_PTR_TO_UNINIT_MEM, 1732 .arg3_type = ARG_CONST_SIZE, 1733 }; 1734 1735 BPF_CALL_3(bpf_sysctl_set_new_value, struct bpf_sysctl_kern *, ctx, 1736 const char *, buf, size_t, buf_len) 1737 { 1738 if (!ctx->write || !ctx->new_val || !ctx->new_len || !buf || !buf_len) 1739 return -EINVAL; 1740 1741 if (buf_len > PAGE_SIZE - 1) 1742 return -E2BIG; 1743 1744 memcpy(ctx->new_val, buf, buf_len); 1745 ctx->new_len = buf_len; 1746 ctx->new_updated = 1; 1747 1748 return 0; 1749 } 1750 1751 static const struct bpf_func_proto bpf_sysctl_set_new_value_proto = { 1752 .func = bpf_sysctl_set_new_value, 1753 .gpl_only = false, 1754 .ret_type = RET_INTEGER, 1755 .arg1_type = ARG_PTR_TO_CTX, 1756 .arg2_type = ARG_PTR_TO_MEM, 1757 .arg3_type = ARG_CONST_SIZE, 1758 }; 1759 1760 static const struct bpf_func_proto * 1761 sysctl_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 1762 { 1763 switch (func_id) { 1764 case BPF_FUNC_strtol: 1765 return &bpf_strtol_proto; 1766 case BPF_FUNC_strtoul: 1767 return &bpf_strtoul_proto; 1768 case BPF_FUNC_sysctl_get_name: 1769 return &bpf_sysctl_get_name_proto; 1770 case BPF_FUNC_sysctl_get_current_value: 1771 return &bpf_sysctl_get_current_value_proto; 1772 case BPF_FUNC_sysctl_get_new_value: 1773 return &bpf_sysctl_get_new_value_proto; 1774 case BPF_FUNC_sysctl_set_new_value: 1775 return &bpf_sysctl_set_new_value_proto; 1776 default: 1777 return cgroup_base_func_proto(func_id, prog); 1778 } 1779 } 1780 1781 static bool sysctl_is_valid_access(int off, int size, enum bpf_access_type type, 1782 const struct bpf_prog *prog, 1783 struct bpf_insn_access_aux *info) 1784 { 1785 const int size_default = sizeof(__u32); 1786 1787 if (off < 0 || off + size > sizeof(struct bpf_sysctl) || off % size) 1788 return false; 1789 1790 switch (off) { 1791 case bpf_ctx_range(struct bpf_sysctl, write): 1792 if (type != BPF_READ) 1793 return false; 1794 bpf_ctx_record_field_size(info, size_default); 1795 return bpf_ctx_narrow_access_ok(off, size, size_default); 1796 case bpf_ctx_range(struct bpf_sysctl, file_pos): 1797 if (type == BPF_READ) { 1798 bpf_ctx_record_field_size(info, size_default); 1799 return bpf_ctx_narrow_access_ok(off, size, size_default); 1800 } else { 1801 return size == size_default; 1802 } 1803 default: 1804 return false; 1805 } 1806 } 1807 1808 static u32 sysctl_convert_ctx_access(enum bpf_access_type type, 1809 const struct bpf_insn *si, 1810 struct bpf_insn *insn_buf, 1811 struct bpf_prog *prog, u32 *target_size) 1812 { 1813 struct bpf_insn *insn = insn_buf; 1814 u32 read_size; 1815 1816 switch (si->off) { 1817 case offsetof(struct bpf_sysctl, write): 1818 *insn++ = BPF_LDX_MEM( 1819 BPF_SIZE(si->code), si->dst_reg, si->src_reg, 1820 bpf_target_off(struct bpf_sysctl_kern, write, 1821 sizeof_field(struct bpf_sysctl_kern, 1822 write), 1823 target_size)); 1824 break; 1825 case offsetof(struct bpf_sysctl, file_pos): 1826 /* ppos is a pointer so it should be accessed via indirect 1827 * loads and stores. Also for stores additional temporary 1828 * register is used since neither src_reg nor dst_reg can be 1829 * overridden. 1830 */ 1831 if (type == BPF_WRITE) { 1832 int treg = BPF_REG_9; 1833 1834 if (si->src_reg == treg || si->dst_reg == treg) 1835 --treg; 1836 if (si->src_reg == treg || si->dst_reg == treg) 1837 --treg; 1838 *insn++ = BPF_STX_MEM( 1839 BPF_DW, si->dst_reg, treg, 1840 offsetof(struct bpf_sysctl_kern, tmp_reg)); 1841 *insn++ = BPF_LDX_MEM( 1842 BPF_FIELD_SIZEOF(struct bpf_sysctl_kern, ppos), 1843 treg, si->dst_reg, 1844 offsetof(struct bpf_sysctl_kern, ppos)); 1845 *insn++ = BPF_STX_MEM( 1846 BPF_SIZEOF(u32), treg, si->src_reg, 1847 bpf_ctx_narrow_access_offset( 1848 0, sizeof(u32), sizeof(loff_t))); 1849 *insn++ = BPF_LDX_MEM( 1850 BPF_DW, treg, si->dst_reg, 1851 offsetof(struct bpf_sysctl_kern, tmp_reg)); 1852 } else { 1853 *insn++ = BPF_LDX_MEM( 1854 BPF_FIELD_SIZEOF(struct bpf_sysctl_kern, ppos), 1855 si->dst_reg, si->src_reg, 1856 offsetof(struct bpf_sysctl_kern, ppos)); 1857 read_size = bpf_size_to_bytes(BPF_SIZE(si->code)); 1858 *insn++ = BPF_LDX_MEM( 1859 BPF_SIZE(si->code), si->dst_reg, si->dst_reg, 1860 bpf_ctx_narrow_access_offset( 1861 0, read_size, sizeof(loff_t))); 1862 } 1863 *target_size = sizeof(u32); 1864 break; 1865 } 1866 1867 return insn - insn_buf; 1868 } 1869 1870 const struct bpf_verifier_ops cg_sysctl_verifier_ops = { 1871 .get_func_proto = sysctl_func_proto, 1872 .is_valid_access = sysctl_is_valid_access, 1873 .convert_ctx_access = sysctl_convert_ctx_access, 1874 }; 1875 1876 const struct bpf_prog_ops cg_sysctl_prog_ops = { 1877 }; 1878 1879 #ifdef CONFIG_NET 1880 BPF_CALL_1(bpf_get_netns_cookie_sockopt, struct bpf_sockopt_kern *, ctx) 1881 { 1882 const struct net *net = ctx ? sock_net(ctx->sk) : &init_net; 1883 1884 return net->net_cookie; 1885 } 1886 1887 static const struct bpf_func_proto bpf_get_netns_cookie_sockopt_proto = { 1888 .func = bpf_get_netns_cookie_sockopt, 1889 .gpl_only = false, 1890 .ret_type = RET_INTEGER, 1891 .arg1_type = ARG_PTR_TO_CTX_OR_NULL, 1892 }; 1893 #endif 1894 1895 static const struct bpf_func_proto * 1896 cg_sockopt_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 1897 { 1898 switch (func_id) { 1899 #ifdef CONFIG_NET 1900 case BPF_FUNC_get_netns_cookie: 1901 return &bpf_get_netns_cookie_sockopt_proto; 1902 case BPF_FUNC_sk_storage_get: 1903 return &bpf_sk_storage_get_proto; 1904 case BPF_FUNC_sk_storage_delete: 1905 return &bpf_sk_storage_delete_proto; 1906 case BPF_FUNC_setsockopt: 1907 if (prog->expected_attach_type == BPF_CGROUP_SETSOCKOPT) 1908 return &bpf_sk_setsockopt_proto; 1909 return NULL; 1910 case BPF_FUNC_getsockopt: 1911 if (prog->expected_attach_type == BPF_CGROUP_SETSOCKOPT) 1912 return &bpf_sk_getsockopt_proto; 1913 return NULL; 1914 #endif 1915 #ifdef CONFIG_INET 1916 case BPF_FUNC_tcp_sock: 1917 return &bpf_tcp_sock_proto; 1918 #endif 1919 default: 1920 return cgroup_base_func_proto(func_id, prog); 1921 } 1922 } 1923 1924 static bool cg_sockopt_is_valid_access(int off, int size, 1925 enum bpf_access_type type, 1926 const struct bpf_prog *prog, 1927 struct bpf_insn_access_aux *info) 1928 { 1929 const int size_default = sizeof(__u32); 1930 1931 if (off < 0 || off >= sizeof(struct bpf_sockopt)) 1932 return false; 1933 1934 if (off % size != 0) 1935 return false; 1936 1937 if (type == BPF_WRITE) { 1938 switch (off) { 1939 case offsetof(struct bpf_sockopt, retval): 1940 if (size != size_default) 1941 return false; 1942 return prog->expected_attach_type == 1943 BPF_CGROUP_GETSOCKOPT; 1944 case offsetof(struct bpf_sockopt, optname): 1945 fallthrough; 1946 case offsetof(struct bpf_sockopt, level): 1947 if (size != size_default) 1948 return false; 1949 return prog->expected_attach_type == 1950 BPF_CGROUP_SETSOCKOPT; 1951 case offsetof(struct bpf_sockopt, optlen): 1952 return size == size_default; 1953 default: 1954 return false; 1955 } 1956 } 1957 1958 switch (off) { 1959 case offsetof(struct bpf_sockopt, sk): 1960 if (size != sizeof(__u64)) 1961 return false; 1962 info->reg_type = PTR_TO_SOCKET; 1963 break; 1964 case offsetof(struct bpf_sockopt, optval): 1965 if (size != sizeof(__u64)) 1966 return false; 1967 info->reg_type = PTR_TO_PACKET; 1968 break; 1969 case offsetof(struct bpf_sockopt, optval_end): 1970 if (size != sizeof(__u64)) 1971 return false; 1972 info->reg_type = PTR_TO_PACKET_END; 1973 break; 1974 case offsetof(struct bpf_sockopt, retval): 1975 if (size != size_default) 1976 return false; 1977 return prog->expected_attach_type == BPF_CGROUP_GETSOCKOPT; 1978 default: 1979 if (size != size_default) 1980 return false; 1981 break; 1982 } 1983 return true; 1984 } 1985 1986 #define CG_SOCKOPT_ACCESS_FIELD(T, F) \ 1987 T(BPF_FIELD_SIZEOF(struct bpf_sockopt_kern, F), \ 1988 si->dst_reg, si->src_reg, \ 1989 offsetof(struct bpf_sockopt_kern, F)) 1990 1991 static u32 cg_sockopt_convert_ctx_access(enum bpf_access_type type, 1992 const struct bpf_insn *si, 1993 struct bpf_insn *insn_buf, 1994 struct bpf_prog *prog, 1995 u32 *target_size) 1996 { 1997 struct bpf_insn *insn = insn_buf; 1998 1999 switch (si->off) { 2000 case offsetof(struct bpf_sockopt, sk): 2001 *insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_LDX_MEM, sk); 2002 break; 2003 case offsetof(struct bpf_sockopt, level): 2004 if (type == BPF_WRITE) 2005 *insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_STX_MEM, level); 2006 else 2007 *insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_LDX_MEM, level); 2008 break; 2009 case offsetof(struct bpf_sockopt, optname): 2010 if (type == BPF_WRITE) 2011 *insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_STX_MEM, optname); 2012 else 2013 *insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_LDX_MEM, optname); 2014 break; 2015 case offsetof(struct bpf_sockopt, optlen): 2016 if (type == BPF_WRITE) 2017 *insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_STX_MEM, optlen); 2018 else 2019 *insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_LDX_MEM, optlen); 2020 break; 2021 case offsetof(struct bpf_sockopt, retval): 2022 if (type == BPF_WRITE) 2023 *insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_STX_MEM, retval); 2024 else 2025 *insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_LDX_MEM, retval); 2026 break; 2027 case offsetof(struct bpf_sockopt, optval): 2028 *insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_LDX_MEM, optval); 2029 break; 2030 case offsetof(struct bpf_sockopt, optval_end): 2031 *insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_LDX_MEM, optval_end); 2032 break; 2033 } 2034 2035 return insn - insn_buf; 2036 } 2037 2038 static int cg_sockopt_get_prologue(struct bpf_insn *insn_buf, 2039 bool direct_write, 2040 const struct bpf_prog *prog) 2041 { 2042 /* Nothing to do for sockopt argument. The data is kzalloc'ated. 2043 */ 2044 return 0; 2045 } 2046 2047 const struct bpf_verifier_ops cg_sockopt_verifier_ops = { 2048 .get_func_proto = cg_sockopt_func_proto, 2049 .is_valid_access = cg_sockopt_is_valid_access, 2050 .convert_ctx_access = cg_sockopt_convert_ctx_access, 2051 .gen_prologue = cg_sockopt_get_prologue, 2052 }; 2053 2054 const struct bpf_prog_ops cg_sockopt_prog_ops = { 2055 }; 2056