kernel/bpf/cgroup.c

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