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- // SPDX-License-Identifier: GPL-2.0-only
- /*
- * Functions to manage eBPF programs attached to cgroups
- *
- * Copyright (c) 2016 Daniel Mack
- */
- #include <linux/kernel.h>
- #include <linux/atomic.h>
- #include <linux/cgroup.h>
- #include <linux/filter.h>
- #include <linux/slab.h>
- #include <linux/sysctl.h>
- #include <linux/string.h>
- #include <linux/bpf.h>
- #include <linux/bpf-cgroup.h>
- #include <net/sock.h>
- #include <net/bpf_sk_storage.h>
- #include "../cgroup/cgroup-internal.h"
- DEFINE_STATIC_KEY_FALSE(cgroup_bpf_enabled_key);
- EXPORT_SYMBOL(cgroup_bpf_enabled_key);
- void cgroup_bpf_offline(struct cgroup *cgrp)
- {
- cgroup_get(cgrp);
- percpu_ref_kill(&cgrp->bpf.refcnt);
- }
- static void bpf_cgroup_storages_free(struct bpf_cgroup_storage *storages[])
- {
- enum bpf_cgroup_storage_type stype;
- for_each_cgroup_storage_type(stype)
- bpf_cgroup_storage_free(storages[stype]);
- }
- static int bpf_cgroup_storages_alloc(struct bpf_cgroup_storage *storages[],
- struct bpf_cgroup_storage *new_storages[],
- enum bpf_attach_type type,
- struct bpf_prog *prog,
- struct cgroup *cgrp)
- {
- enum bpf_cgroup_storage_type stype;
- struct bpf_cgroup_storage_key key;
- struct bpf_map *map;
- key.cgroup_inode_id = cgroup_id(cgrp);
- key.attach_type = type;
- for_each_cgroup_storage_type(stype) {
- map = prog->aux->cgroup_storage[stype];
- if (!map)
- continue;
- storages[stype] = cgroup_storage_lookup((void *)map, &key, false);
- if (storages[stype])
- continue;
- storages[stype] = bpf_cgroup_storage_alloc(prog, stype);
- if (IS_ERR(storages[stype])) {
- bpf_cgroup_storages_free(new_storages);
- return -ENOMEM;
- }
- new_storages[stype] = storages[stype];
- }
- return 0;
- }
- static void bpf_cgroup_storages_assign(struct bpf_cgroup_storage *dst[],
- struct bpf_cgroup_storage *src[])
- {
- enum bpf_cgroup_storage_type stype;
- for_each_cgroup_storage_type(stype)
- dst[stype] = src[stype];
- }
- static void bpf_cgroup_storages_link(struct bpf_cgroup_storage *storages[],
- struct cgroup *cgrp,
- enum bpf_attach_type attach_type)
- {
- enum bpf_cgroup_storage_type stype;
- for_each_cgroup_storage_type(stype)
- bpf_cgroup_storage_link(storages[stype], cgrp, attach_type);
- }
- /* Called when bpf_cgroup_link is auto-detached from dying cgroup.
- * It drops cgroup and bpf_prog refcounts, and marks bpf_link as defunct. It
- * doesn't free link memory, which will eventually be done by bpf_link's
- * release() callback, when its last FD is closed.
- */
- static void bpf_cgroup_link_auto_detach(struct bpf_cgroup_link *link)
- {
- cgroup_put(link->cgroup);
- link->cgroup = NULL;
- }
- /**
- * cgroup_bpf_release() - put references of all bpf programs and
- * release all cgroup bpf data
- * @work: work structure embedded into the cgroup to modify
- */
- static void cgroup_bpf_release(struct work_struct *work)
- {
- struct cgroup *p, *cgrp = container_of(work, struct cgroup,
- bpf.release_work);
- struct bpf_prog_array *old_array;
- struct list_head *storages = &cgrp->bpf.storages;
- struct bpf_cgroup_storage *storage, *stmp;
- unsigned int type;
- mutex_lock(&cgroup_mutex);
- for (type = 0; type < ARRAY_SIZE(cgrp->bpf.progs); type++) {
- struct list_head *progs = &cgrp->bpf.progs[type];
- struct bpf_prog_list *pl, *pltmp;
- list_for_each_entry_safe(pl, pltmp, progs, node) {
- list_del(&pl->node);
- if (pl->prog)
- bpf_prog_put(pl->prog);
- if (pl->link)
- bpf_cgroup_link_auto_detach(pl->link);
- kfree(pl);
- static_branch_dec(&cgroup_bpf_enabled_key);
- }
- old_array = rcu_dereference_protected(
- cgrp->bpf.effective[type],
- lockdep_is_held(&cgroup_mutex));
- bpf_prog_array_free(old_array);
- }
- list_for_each_entry_safe(storage, stmp, storages, list_cg) {
- bpf_cgroup_storage_unlink(storage);
- bpf_cgroup_storage_free(storage);
- }
- mutex_unlock(&cgroup_mutex);
- for (p = cgroup_parent(cgrp); p; p = cgroup_parent(p))
- cgroup_bpf_put(p);
- percpu_ref_exit(&cgrp->bpf.refcnt);
- cgroup_put(cgrp);
- }
- /**
- * cgroup_bpf_release_fn() - callback used to schedule releasing
- * of bpf cgroup data
- * @ref: percpu ref counter structure
- */
- static void cgroup_bpf_release_fn(struct percpu_ref *ref)
- {
- struct cgroup *cgrp = container_of(ref, struct cgroup, bpf.refcnt);
- INIT_WORK(&cgrp->bpf.release_work, cgroup_bpf_release);
- queue_work(system_wq, &cgrp->bpf.release_work);
- }
- /* Get underlying bpf_prog of bpf_prog_list entry, regardless if it's through
- * link or direct prog.
- */
- static struct bpf_prog *prog_list_prog(struct bpf_prog_list *pl)
- {
- if (pl->prog)
- return pl->prog;
- if (pl->link)
- return pl->link->link.prog;
- return NULL;
- }
- /* count number of elements in the list.
- * it's slow but the list cannot be long
- */
- static u32 prog_list_length(struct list_head *head)
- {
- struct bpf_prog_list *pl;
- u32 cnt = 0;
- list_for_each_entry(pl, head, node) {
- if (!prog_list_prog(pl))
- continue;
- cnt++;
- }
- return cnt;
- }
- /* if parent has non-overridable prog attached,
- * disallow attaching new programs to the descendent cgroup.
- * if parent has overridable or multi-prog, allow attaching
- */
- static bool hierarchy_allows_attach(struct cgroup *cgrp,
- enum bpf_attach_type type)
- {
- struct cgroup *p;
- p = cgroup_parent(cgrp);
- if (!p)
- return true;
- do {
- u32 flags = p->bpf.flags[type];
- u32 cnt;
- if (flags & BPF_F_ALLOW_MULTI)
- return true;
- cnt = prog_list_length(&p->bpf.progs[type]);
- WARN_ON_ONCE(cnt > 1);
- if (cnt == 1)
- return !!(flags & BPF_F_ALLOW_OVERRIDE);
- p = cgroup_parent(p);
- } while (p);
- return true;
- }
- /* compute a chain of effective programs for a given cgroup:
- * start from the list of programs in this cgroup and add
- * all parent programs.
- * Note that parent's F_ALLOW_OVERRIDE-type program is yielding
- * to programs in this cgroup
- */
- static int compute_effective_progs(struct cgroup *cgrp,
- enum bpf_attach_type type,
- struct bpf_prog_array **array)
- {
- struct bpf_prog_array_item *item;
- struct bpf_prog_array *progs;
- struct bpf_prog_list *pl;
- struct cgroup *p = cgrp;
- int cnt = 0;
- /* count number of effective programs by walking parents */
- do {
- if (cnt == 0 || (p->bpf.flags[type] & BPF_F_ALLOW_MULTI))
- cnt += prog_list_length(&p->bpf.progs[type]);
- p = cgroup_parent(p);
- } while (p);
- progs = bpf_prog_array_alloc(cnt, GFP_KERNEL);
- if (!progs)
- return -ENOMEM;
- /* populate the array with effective progs */
- cnt = 0;
- p = cgrp;
- do {
- if (cnt > 0 && !(p->bpf.flags[type] & BPF_F_ALLOW_MULTI))
- continue;
- list_for_each_entry(pl, &p->bpf.progs[type], node) {
- if (!prog_list_prog(pl))
- continue;
- item = &progs->items[cnt];
- item->prog = prog_list_prog(pl);
- bpf_cgroup_storages_assign(item->cgroup_storage,
- pl->storage);
- cnt++;
- }
- } while ((p = cgroup_parent(p)));
- *array = progs;
- return 0;
- }
- static void activate_effective_progs(struct cgroup *cgrp,
- enum bpf_attach_type type,
- struct bpf_prog_array *old_array)
- {
- old_array = rcu_replace_pointer(cgrp->bpf.effective[type], old_array,
- lockdep_is_held(&cgroup_mutex));
- /* free prog array after grace period, since __cgroup_bpf_run_*()
- * might be still walking the array
- */
- bpf_prog_array_free(old_array);
- }
- /**
- * cgroup_bpf_inherit() - inherit effective programs from parent
- * @cgrp: the cgroup to modify
- */
- int cgroup_bpf_inherit(struct cgroup *cgrp)
- {
- /* has to use marco instead of const int, since compiler thinks
- * that array below is variable length
- */
- #define NR ARRAY_SIZE(cgrp->bpf.effective)
- struct bpf_prog_array *arrays[NR] = {};
- struct cgroup *p;
- int ret, i;
- ret = percpu_ref_init(&cgrp->bpf.refcnt, cgroup_bpf_release_fn, 0,
- GFP_KERNEL);
- if (ret)
- return ret;
- for (p = cgroup_parent(cgrp); p; p = cgroup_parent(p))
- cgroup_bpf_get(p);
- for (i = 0; i < NR; i++)
- INIT_LIST_HEAD(&cgrp->bpf.progs[i]);
- INIT_LIST_HEAD(&cgrp->bpf.storages);
- for (i = 0; i < NR; i++)
- if (compute_effective_progs(cgrp, i, &arrays[i]))
- goto cleanup;
- for (i = 0; i < NR; i++)
- activate_effective_progs(cgrp, i, arrays[i]);
- return 0;
- cleanup:
- for (i = 0; i < NR; i++)
- bpf_prog_array_free(arrays[i]);
- for (p = cgroup_parent(cgrp); p; p = cgroup_parent(p))
- cgroup_bpf_put(p);
- percpu_ref_exit(&cgrp->bpf.refcnt);
- return -ENOMEM;
- }
- static int update_effective_progs(struct cgroup *cgrp,
- enum bpf_attach_type type)
- {
- struct cgroup_subsys_state *css;
- int err;
- /* allocate and recompute effective prog arrays */
- css_for_each_descendant_pre(css, &cgrp->self) {
- struct cgroup *desc = container_of(css, struct cgroup, self);
- if (percpu_ref_is_zero(&desc->bpf.refcnt))
- continue;
- err = compute_effective_progs(desc, type, &desc->bpf.inactive);
- if (err)
- goto cleanup;
- }
- /* all allocations were successful. Activate all prog arrays */
- css_for_each_descendant_pre(css, &cgrp->self) {
- struct cgroup *desc = container_of(css, struct cgroup, self);
- if (percpu_ref_is_zero(&desc->bpf.refcnt)) {
- if (unlikely(desc->bpf.inactive)) {
- bpf_prog_array_free(desc->bpf.inactive);
- desc->bpf.inactive = NULL;
- }
- continue;
- }
- activate_effective_progs(desc, type, desc->bpf.inactive);
- desc->bpf.inactive = NULL;
- }
- return 0;
- cleanup:
- /* oom while computing effective. Free all computed effective arrays
- * since they were not activated
- */
- css_for_each_descendant_pre(css, &cgrp->self) {
- struct cgroup *desc = container_of(css, struct cgroup, self);
- bpf_prog_array_free(desc->bpf.inactive);
- desc->bpf.inactive = NULL;
- }
- return err;
- }
- #define BPF_CGROUP_MAX_PROGS 64
- static struct bpf_prog_list *find_attach_entry(struct list_head *progs,
- struct bpf_prog *prog,
- struct bpf_cgroup_link *link,
- struct bpf_prog *replace_prog,
- bool allow_multi)
- {
- struct bpf_prog_list *pl;
- /* single-attach case */
- if (!allow_multi) {
- if (list_empty(progs))
- return NULL;
- return list_first_entry(progs, typeof(*pl), node);
- }
- list_for_each_entry(pl, progs, node) {
- if (prog && pl->prog == prog && prog != replace_prog)
- /* disallow attaching the same prog twice */
- return ERR_PTR(-EINVAL);
- if (link && pl->link == link)
- /* disallow attaching the same link twice */
- return ERR_PTR(-EINVAL);
- }
- /* direct prog multi-attach w/ replacement case */
- if (replace_prog) {
- list_for_each_entry(pl, progs, node) {
- if (pl->prog == replace_prog)
- /* a match found */
- return pl;
- }
- /* prog to replace not found for cgroup */
- return ERR_PTR(-ENOENT);
- }
- return NULL;
- }
- /**
- * __cgroup_bpf_attach() - Attach the program or the link to a cgroup, and
- * propagate the change to descendants
- * @cgrp: The cgroup which descendants to traverse
- * @prog: A program to attach
- * @link: A link to attach
- * @replace_prog: Previously attached program to replace if BPF_F_REPLACE is set
- * @type: Type of attach operation
- * @flags: Option flags
- *
- * Exactly one of @prog or @link can be non-null.
- * Must be called with cgroup_mutex held.
- */
- int __cgroup_bpf_attach(struct cgroup *cgrp,
- struct bpf_prog *prog, struct bpf_prog *replace_prog,
- struct bpf_cgroup_link *link,
- enum bpf_attach_type type, u32 flags)
- {
- u32 saved_flags = (flags & (BPF_F_ALLOW_OVERRIDE | BPF_F_ALLOW_MULTI));
- struct list_head *progs = &cgrp->bpf.progs[type];
- struct bpf_prog *old_prog = NULL;
- struct bpf_cgroup_storage *storage[MAX_BPF_CGROUP_STORAGE_TYPE] = {};
- struct bpf_cgroup_storage *new_storage[MAX_BPF_CGROUP_STORAGE_TYPE] = {};
- struct bpf_prog_list *pl;
- int err;
- if (((flags & BPF_F_ALLOW_OVERRIDE) && (flags & BPF_F_ALLOW_MULTI)) ||
- ((flags & BPF_F_REPLACE) && !(flags & BPF_F_ALLOW_MULTI)))
- /* invalid combination */
- return -EINVAL;
- if (link && (prog || replace_prog))
- /* only either link or prog/replace_prog can be specified */
- return -EINVAL;
- if (!!replace_prog != !!(flags & BPF_F_REPLACE))
- /* replace_prog implies BPF_F_REPLACE, and vice versa */
- return -EINVAL;
- if (!hierarchy_allows_attach(cgrp, type))
- return -EPERM;
- if (!list_empty(progs) && cgrp->bpf.flags[type] != saved_flags)
- /* Disallow attaching non-overridable on top
- * of existing overridable in this cgroup.
- * Disallow attaching multi-prog if overridable or none
- */
- return -EPERM;
- if (prog_list_length(progs) >= BPF_CGROUP_MAX_PROGS)
- return -E2BIG;
- pl = find_attach_entry(progs, prog, link, replace_prog,
- flags & BPF_F_ALLOW_MULTI);
- if (IS_ERR(pl))
- return PTR_ERR(pl);
- if (bpf_cgroup_storages_alloc(storage, new_storage, type,
- prog ? : link->link.prog, cgrp))
- return -ENOMEM;
- if (pl) {
- old_prog = pl->prog;
- } else {
- pl = kmalloc(sizeof(*pl), GFP_KERNEL);
- if (!pl) {
- bpf_cgroup_storages_free(new_storage);
- return -ENOMEM;
- }
- list_add_tail(&pl->node, progs);
- }
- pl->prog = prog;
- pl->link = link;
- bpf_cgroup_storages_assign(pl->storage, storage);
- cgrp->bpf.flags[type] = saved_flags;
- err = update_effective_progs(cgrp, type);
- if (err)
- goto cleanup;
- if (old_prog)
- bpf_prog_put(old_prog);
- else
- static_branch_inc(&cgroup_bpf_enabled_key);
- bpf_cgroup_storages_link(new_storage, cgrp, type);
- return 0;
- cleanup:
- if (old_prog) {
- pl->prog = old_prog;
- pl->link = NULL;
- }
- bpf_cgroup_storages_free(new_storage);
- if (!old_prog) {
- list_del(&pl->node);
- kfree(pl);
- }
- return err;
- }
- /* Swap updated BPF program for given link in effective program arrays across
- * all descendant cgroups. This function is guaranteed to succeed.
- */
- static void replace_effective_prog(struct cgroup *cgrp,
- enum bpf_attach_type type,
- struct bpf_cgroup_link *link)
- {
- struct bpf_prog_array_item *item;
- struct cgroup_subsys_state *css;
- struct bpf_prog_array *progs;
- struct bpf_prog_list *pl;
- struct list_head *head;
- struct cgroup *cg;
- int pos;
- css_for_each_descendant_pre(css, &cgrp->self) {
- struct cgroup *desc = container_of(css, struct cgroup, self);
- if (percpu_ref_is_zero(&desc->bpf.refcnt))
- continue;
- /* find position of link in effective progs array */
- for (pos = 0, cg = desc; cg; cg = cgroup_parent(cg)) {
- if (pos && !(cg->bpf.flags[type] & BPF_F_ALLOW_MULTI))
- continue;
- head = &cg->bpf.progs[type];
- list_for_each_entry(pl, head, node) {
- if (!prog_list_prog(pl))
- continue;
- if (pl->link == link)
- goto found;
- pos++;
- }
- }
- found:
- BUG_ON(!cg);
- progs = rcu_dereference_protected(
- desc->bpf.effective[type],
- lockdep_is_held(&cgroup_mutex));
- item = &progs->items[pos];
- WRITE_ONCE(item->prog, link->link.prog);
- }
- }
- /**
- * __cgroup_bpf_replace() - Replace link's program and propagate the change
- * to descendants
- * @cgrp: The cgroup which descendants to traverse
- * @link: A link for which to replace BPF program
- * @type: Type of attach operation
- *
- * Must be called with cgroup_mutex held.
- */
- static int __cgroup_bpf_replace(struct cgroup *cgrp,
- struct bpf_cgroup_link *link,
- struct bpf_prog *new_prog)
- {
- struct list_head *progs = &cgrp->bpf.progs[link->type];
- struct bpf_prog *old_prog;
- struct bpf_prog_list *pl;
- bool found = false;
- if (link->link.prog->type != new_prog->type)
- return -EINVAL;
- list_for_each_entry(pl, progs, node) {
- if (pl->link == link) {
- found = true;
- break;
- }
- }
- if (!found)
- return -ENOENT;
- old_prog = xchg(&link->link.prog, new_prog);
- replace_effective_prog(cgrp, link->type, link);
- bpf_prog_put(old_prog);
- return 0;
- }
- static int cgroup_bpf_replace(struct bpf_link *link, struct bpf_prog *new_prog,
- struct bpf_prog *old_prog)
- {
- struct bpf_cgroup_link *cg_link;
- int ret;
- cg_link = container_of(link, struct bpf_cgroup_link, link);
- mutex_lock(&cgroup_mutex);
- /* link might have been auto-released by dying cgroup, so fail */
- if (!cg_link->cgroup) {
- ret = -ENOLINK;
- goto out_unlock;
- }
- if (old_prog && link->prog != old_prog) {
- ret = -EPERM;
- goto out_unlock;
- }
- ret = __cgroup_bpf_replace(cg_link->cgroup, cg_link, new_prog);
- out_unlock:
- mutex_unlock(&cgroup_mutex);
- return ret;
- }
- static struct bpf_prog_list *find_detach_entry(struct list_head *progs,
- struct bpf_prog *prog,
- struct bpf_cgroup_link *link,
- bool allow_multi)
- {
- struct bpf_prog_list *pl;
- if (!allow_multi) {
- if (list_empty(progs))
- /* report error when trying to detach and nothing is attached */
- return ERR_PTR(-ENOENT);
- /* to maintain backward compatibility NONE and OVERRIDE cgroups
- * allow detaching with invalid FD (prog==NULL) in legacy mode
- */
- return list_first_entry(progs, typeof(*pl), node);
- }
- if (!prog && !link)
- /* to detach MULTI prog the user has to specify valid FD
- * of the program or link to be detached
- */
- return ERR_PTR(-EINVAL);
- /* find the prog or link and detach it */
- list_for_each_entry(pl, progs, node) {
- if (pl->prog == prog && pl->link == link)
- return pl;
- }
- return ERR_PTR(-ENOENT);
- }
- /**
- * __cgroup_bpf_detach() - Detach the program or link from a cgroup, and
- * propagate the change to descendants
- * @cgrp: The cgroup which descendants to traverse
- * @prog: A program to detach or NULL
- * @prog: A link to detach or NULL
- * @type: Type of detach operation
- *
- * At most one of @prog or @link can be non-NULL.
- * Must be called with cgroup_mutex held.
- */
- int __cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog,
- struct bpf_cgroup_link *link, enum bpf_attach_type type)
- {
- struct list_head *progs = &cgrp->bpf.progs[type];
- u32 flags = cgrp->bpf.flags[type];
- struct bpf_prog_list *pl;
- struct bpf_prog *old_prog;
- int err;
- if (prog && link)
- /* only one of prog or link can be specified */
- return -EINVAL;
- pl = find_detach_entry(progs, prog, link, flags & BPF_F_ALLOW_MULTI);
- if (IS_ERR(pl))
- return PTR_ERR(pl);
- /* mark it deleted, so it's ignored while recomputing effective */
- old_prog = pl->prog;
- pl->prog = NULL;
- pl->link = NULL;
- err = update_effective_progs(cgrp, type);
- if (err)
- goto cleanup;
- /* now can actually delete it from this cgroup list */
- list_del(&pl->node);
- kfree(pl);
- if (list_empty(progs))
- /* last program was detached, reset flags to zero */
- cgrp->bpf.flags[type] = 0;
- if (old_prog)
- bpf_prog_put(old_prog);
- static_branch_dec(&cgroup_bpf_enabled_key);
- return 0;
- cleanup:
- /* restore back prog or link */
- pl->prog = old_prog;
- pl->link = link;
- return err;
- }
- /* Must be called with cgroup_mutex held to avoid races. */
- int __cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr,
- union bpf_attr __user *uattr)
- {
- __u32 __user *prog_ids = u64_to_user_ptr(attr->query.prog_ids);
- enum bpf_attach_type type = attr->query.attach_type;
- struct list_head *progs = &cgrp->bpf.progs[type];
- u32 flags = cgrp->bpf.flags[type];
- struct bpf_prog_array *effective;
- struct bpf_prog *prog;
- int cnt, ret = 0, i;
- effective = rcu_dereference_protected(cgrp->bpf.effective[type],
- lockdep_is_held(&cgroup_mutex));
- if (attr->query.query_flags & BPF_F_QUERY_EFFECTIVE)
- cnt = bpf_prog_array_length(effective);
- else
- cnt = prog_list_length(progs);
- if (copy_to_user(&uattr->query.attach_flags, &flags, sizeof(flags)))
- return -EFAULT;
- if (copy_to_user(&uattr->query.prog_cnt, &cnt, sizeof(cnt)))
- return -EFAULT;
- if (attr->query.prog_cnt == 0 || !prog_ids || !cnt)
- /* return early if user requested only program count + flags */
- return 0;
- if (attr->query.prog_cnt < cnt) {
- cnt = attr->query.prog_cnt;
- ret = -ENOSPC;
- }
- if (attr->query.query_flags & BPF_F_QUERY_EFFECTIVE) {
- return bpf_prog_array_copy_to_user(effective, prog_ids, cnt);
- } else {
- struct bpf_prog_list *pl;
- u32 id;
- i = 0;
- list_for_each_entry(pl, progs, node) {
- prog = prog_list_prog(pl);
- id = prog->aux->id;
- if (copy_to_user(prog_ids + i, &id, sizeof(id)))
- return -EFAULT;
- if (++i == cnt)
- break;
- }
- }
- return ret;
- }
- int cgroup_bpf_prog_attach(const union bpf_attr *attr,
- enum bpf_prog_type ptype, struct bpf_prog *prog)
- {
- struct bpf_prog *replace_prog = NULL;
- struct cgroup *cgrp;
- int ret;
- cgrp = cgroup_get_from_fd(attr->target_fd);
- if (IS_ERR(cgrp))
- return PTR_ERR(cgrp);
- if ((attr->attach_flags & BPF_F_ALLOW_MULTI) &&
- (attr->attach_flags & BPF_F_REPLACE)) {
- replace_prog = bpf_prog_get_type(attr->replace_bpf_fd, ptype);
- if (IS_ERR(replace_prog)) {
- cgroup_put(cgrp);
- return PTR_ERR(replace_prog);
- }
- }
- ret = cgroup_bpf_attach(cgrp, prog, replace_prog, NULL,
- attr->attach_type, attr->attach_flags);
- if (replace_prog)
- bpf_prog_put(replace_prog);
- cgroup_put(cgrp);
- return ret;
- }
- int cgroup_bpf_prog_detach(const union bpf_attr *attr, enum bpf_prog_type ptype)
- {
- struct bpf_prog *prog;
- struct cgroup *cgrp;
- int ret;
- cgrp = cgroup_get_from_fd(attr->target_fd);
- if (IS_ERR(cgrp))
- return PTR_ERR(cgrp);
- prog = bpf_prog_get_type(attr->attach_bpf_fd, ptype);
- if (IS_ERR(prog))
- prog = NULL;
- ret = cgroup_bpf_detach(cgrp, prog, attr->attach_type);
- if (prog)
- bpf_prog_put(prog);
- cgroup_put(cgrp);
- return ret;
- }
- static void bpf_cgroup_link_release(struct bpf_link *link)
- {
- struct bpf_cgroup_link *cg_link =
- container_of(link, struct bpf_cgroup_link, link);
- struct cgroup *cg;
- /* link might have been auto-detached by dying cgroup already,
- * in that case our work is done here
- */
- if (!cg_link->cgroup)
- return;
- mutex_lock(&cgroup_mutex);
- /* re-check cgroup under lock again */
- if (!cg_link->cgroup) {
- mutex_unlock(&cgroup_mutex);
- return;
- }
- WARN_ON(__cgroup_bpf_detach(cg_link->cgroup, NULL, cg_link,
- cg_link->type));
- cg = cg_link->cgroup;
- cg_link->cgroup = NULL;
- mutex_unlock(&cgroup_mutex);
- cgroup_put(cg);
- }
- static void bpf_cgroup_link_dealloc(struct bpf_link *link)
- {
- struct bpf_cgroup_link *cg_link =
- container_of(link, struct bpf_cgroup_link, link);
- kfree(cg_link);
- }
- static int bpf_cgroup_link_detach(struct bpf_link *link)
- {
- bpf_cgroup_link_release(link);
- return 0;
- }
- static void bpf_cgroup_link_show_fdinfo(const struct bpf_link *link,
- struct seq_file *seq)
- {
- struct bpf_cgroup_link *cg_link =
- container_of(link, struct bpf_cgroup_link, link);
- u64 cg_id = 0;
- mutex_lock(&cgroup_mutex);
- if (cg_link->cgroup)
- cg_id = cgroup_id(cg_link->cgroup);
- mutex_unlock(&cgroup_mutex);
- seq_printf(seq,
- "cgroup_id:\t%llu\n"
- "attach_type:\t%d\n",
- cg_id,
- cg_link->type);
- }
- static int bpf_cgroup_link_fill_link_info(const struct bpf_link *link,
- struct bpf_link_info *info)
- {
- struct bpf_cgroup_link *cg_link =
- container_of(link, struct bpf_cgroup_link, link);
- u64 cg_id = 0;
- mutex_lock(&cgroup_mutex);
- if (cg_link->cgroup)
- cg_id = cgroup_id(cg_link->cgroup);
- mutex_unlock(&cgroup_mutex);
- info->cgroup.cgroup_id = cg_id;
- info->cgroup.attach_type = cg_link->type;
- return 0;
- }
- static const struct bpf_link_ops bpf_cgroup_link_lops = {
- .release = bpf_cgroup_link_release,
- .dealloc = bpf_cgroup_link_dealloc,
- .detach = bpf_cgroup_link_detach,
- .update_prog = cgroup_bpf_replace,
- .show_fdinfo = bpf_cgroup_link_show_fdinfo,
- .fill_link_info = bpf_cgroup_link_fill_link_info,
- };
- int cgroup_bpf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
- {
- struct bpf_link_primer link_primer;
- struct bpf_cgroup_link *link;
- struct cgroup *cgrp;
- int err;
- if (attr->link_create.flags)
- return -EINVAL;
- cgrp = cgroup_get_from_fd(attr->link_create.target_fd);
- if (IS_ERR(cgrp))
- return PTR_ERR(cgrp);
- link = kzalloc(sizeof(*link), GFP_USER);
- if (!link) {
- err = -ENOMEM;
- goto out_put_cgroup;
- }
- bpf_link_init(&link->link, BPF_LINK_TYPE_CGROUP, &bpf_cgroup_link_lops,
- prog);
- link->cgroup = cgrp;
- link->type = attr->link_create.attach_type;
- err = bpf_link_prime(&link->link, &link_primer);
- if (err) {
- kfree(link);
- goto out_put_cgroup;
- }
- err = cgroup_bpf_attach(cgrp, NULL, NULL, link, link->type,
- BPF_F_ALLOW_MULTI);
- if (err) {
- bpf_link_cleanup(&link_primer);
- goto out_put_cgroup;
- }
- return bpf_link_settle(&link_primer);
- out_put_cgroup:
- cgroup_put(cgrp);
- return err;
- }
- int cgroup_bpf_prog_query(const union bpf_attr *attr,
- union bpf_attr __user *uattr)
- {
- struct cgroup *cgrp;
- int ret;
- cgrp = cgroup_get_from_fd(attr->query.target_fd);
- if (IS_ERR(cgrp))
- return PTR_ERR(cgrp);
- ret = cgroup_bpf_query(cgrp, attr, uattr);
- cgroup_put(cgrp);
- return ret;
- }
- /**
- * __cgroup_bpf_run_filter_skb() - Run a program for packet filtering
- * @sk: The socket sending or receiving traffic
- * @skb: The skb that is being sent or received
- * @type: The type of program to be exectuted
- *
- * If no socket is passed, or the socket is not of type INET or INET6,
- * this function does nothing and returns 0.
- *
- * The program type passed in via @type must be suitable for network
- * filtering. No further check is performed to assert that.
- *
- * For egress packets, this function can return:
- * NET_XMIT_SUCCESS (0) - continue with packet output
- * NET_XMIT_DROP (1) - drop packet and notify TCP to call cwr
- * NET_XMIT_CN (2) - continue with packet output and notify TCP
- * to call cwr
- * -EPERM - drop packet
- *
- * For ingress packets, this function will return -EPERM if any
- * attached program was found and if it returned != 1 during execution.
- * Otherwise 0 is returned.
- */
- int __cgroup_bpf_run_filter_skb(struct sock *sk,
- struct sk_buff *skb,
- enum bpf_attach_type type)
- {
- unsigned int offset = skb->data - skb_network_header(skb);
- struct sock *save_sk;
- void *saved_data_end;
- struct cgroup *cgrp;
- int ret;
- if (!sk || !sk_fullsock(sk))
- return 0;
- if (sk->sk_family != AF_INET && sk->sk_family != AF_INET6)
- return 0;
- cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
- save_sk = skb->sk;
- skb->sk = sk;
- __skb_push(skb, offset);
- /* compute pointers for the bpf prog */
- bpf_compute_and_save_data_end(skb, &saved_data_end);
- if (type == BPF_CGROUP_INET_EGRESS) {
- ret = BPF_PROG_CGROUP_INET_EGRESS_RUN_ARRAY(
- cgrp->bpf.effective[type], skb, __bpf_prog_run_save_cb);
- } else {
- ret = BPF_PROG_RUN_ARRAY(cgrp->bpf.effective[type], skb,
- __bpf_prog_run_save_cb);
- ret = (ret == 1 ? 0 : -EPERM);
- }
- bpf_restore_data_end(skb, saved_data_end);
- __skb_pull(skb, offset);
- skb->sk = save_sk;
- return ret;
- }
- EXPORT_SYMBOL(__cgroup_bpf_run_filter_skb);
- /**
- * __cgroup_bpf_run_filter_sk() - Run a program on a sock
- * @sk: sock structure to manipulate
- * @type: The type of program to be exectuted
- *
- * socket is passed is expected to be of type INET or INET6.
- *
- * The program type passed in via @type must be suitable for sock
- * filtering. No further check is performed to assert that.
- *
- * This function will return %-EPERM if any if an attached program was found
- * and if it returned != 1 during execution. In all other cases, 0 is returned.
- */
- int __cgroup_bpf_run_filter_sk(struct sock *sk,
- enum bpf_attach_type type)
- {
- struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
- int ret;
- ret = BPF_PROG_RUN_ARRAY(cgrp->bpf.effective[type], sk, BPF_PROG_RUN);
- return ret == 1 ? 0 : -EPERM;
- }
- EXPORT_SYMBOL(__cgroup_bpf_run_filter_sk);
- /**
- * __cgroup_bpf_run_filter_sock_addr() - Run a program on a sock and
- * provided by user sockaddr
- * @sk: sock struct that will use sockaddr
- * @uaddr: sockaddr struct provided by user
- * @type: The type of program to be exectuted
- * @t_ctx: Pointer to attach type specific context
- *
- * socket is expected to be of type INET or INET6.
- *
- * This function will return %-EPERM if an attached program is found and
- * returned value != 1 during execution. In all other cases, 0 is returned.
- */
- int __cgroup_bpf_run_filter_sock_addr(struct sock *sk,
- struct sockaddr *uaddr,
- enum bpf_attach_type type,
- void *t_ctx)
- {
- struct bpf_sock_addr_kern ctx = {
- .sk = sk,
- .uaddr = uaddr,
- .t_ctx = t_ctx,
- };
- struct sockaddr_storage unspec;
- struct cgroup *cgrp;
- int ret;
- /* Check socket family since not all sockets represent network
- * endpoint (e.g. AF_UNIX).
- */
- if (sk->sk_family != AF_INET && sk->sk_family != AF_INET6)
- return 0;
- if (!ctx.uaddr) {
- memset(&unspec, 0, sizeof(unspec));
- ctx.uaddr = (struct sockaddr *)&unspec;
- }
- cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
- ret = BPF_PROG_RUN_ARRAY(cgrp->bpf.effective[type], &ctx, BPF_PROG_RUN);
- return ret == 1 ? 0 : -EPERM;
- }
- EXPORT_SYMBOL(__cgroup_bpf_run_filter_sock_addr);
- /**
- * __cgroup_bpf_run_filter_sock_ops() - Run a program on a sock
- * @sk: socket to get cgroup from
- * @sock_ops: bpf_sock_ops_kern struct to pass to program. Contains
- * sk with connection information (IP addresses, etc.) May not contain
- * cgroup info if it is a req sock.
- * @type: The type of program to be exectuted
- *
- * socket passed is expected to be of type INET or INET6.
- *
- * The program type passed in via @type must be suitable for sock_ops
- * filtering. No further check is performed to assert that.
- *
- * This function will return %-EPERM if any if an attached program was found
- * and if it returned != 1 during execution. In all other cases, 0 is returned.
- */
- int __cgroup_bpf_run_filter_sock_ops(struct sock *sk,
- struct bpf_sock_ops_kern *sock_ops,
- enum bpf_attach_type type)
- {
- struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
- int ret;
- ret = BPF_PROG_RUN_ARRAY(cgrp->bpf.effective[type], sock_ops,
- BPF_PROG_RUN);
- return ret == 1 ? 0 : -EPERM;
- }
- EXPORT_SYMBOL(__cgroup_bpf_run_filter_sock_ops);
- int __cgroup_bpf_check_dev_permission(short dev_type, u32 major, u32 minor,
- short access, enum bpf_attach_type type)
- {
- struct cgroup *cgrp;
- struct bpf_cgroup_dev_ctx ctx = {
- .access_type = (access << 16) | dev_type,
- .major = major,
- .minor = minor,
- };
- int allow = 1;
- rcu_read_lock();
- cgrp = task_dfl_cgroup(current);
- allow = BPF_PROG_RUN_ARRAY(cgrp->bpf.effective[type], &ctx,
- BPF_PROG_RUN);
- rcu_read_unlock();
- return !allow;
- }
- static const struct bpf_func_proto *
- cgroup_base_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
- {
- switch (func_id) {
- case BPF_FUNC_get_current_uid_gid:
- return &bpf_get_current_uid_gid_proto;
- case BPF_FUNC_get_local_storage:
- return &bpf_get_local_storage_proto;
- case BPF_FUNC_get_current_cgroup_id:
- return &bpf_get_current_cgroup_id_proto;
- case BPF_FUNC_perf_event_output:
- return &bpf_event_output_data_proto;
- default:
- return bpf_base_func_proto(func_id);
- }
- }
- static const struct bpf_func_proto *
- cgroup_dev_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
- {
- return cgroup_base_func_proto(func_id, prog);
- }
- static bool cgroup_dev_is_valid_access(int off, int size,
- enum bpf_access_type type,
- const struct bpf_prog *prog,
- struct bpf_insn_access_aux *info)
- {
- const int size_default = sizeof(__u32);
- if (type == BPF_WRITE)
- return false;
- if (off < 0 || off + size > sizeof(struct bpf_cgroup_dev_ctx))
- return false;
- /* The verifier guarantees that size > 0. */
- if (off % size != 0)
- return false;
- switch (off) {
- case bpf_ctx_range(struct bpf_cgroup_dev_ctx, access_type):
- bpf_ctx_record_field_size(info, size_default);
- if (!bpf_ctx_narrow_access_ok(off, size, size_default))
- return false;
- break;
- default:
- if (size != size_default)
- return false;
- }
- return true;
- }
- const struct bpf_prog_ops cg_dev_prog_ops = {
- };
- const struct bpf_verifier_ops cg_dev_verifier_ops = {
- .get_func_proto = cgroup_dev_func_proto,
- .is_valid_access = cgroup_dev_is_valid_access,
- };
- /**
- * __cgroup_bpf_run_filter_sysctl - Run a program on sysctl
- *
- * @head: sysctl table header
- * @table: sysctl table
- * @write: sysctl is being read (= 0) or written (= 1)
- * @buf: pointer to buffer (in and out)
- * @pcount: value-result argument: value is size of buffer pointed to by @buf,
- * result is size of @new_buf if program set new value, initial value
- * otherwise
- * @ppos: value-result argument: value is position at which read from or write
- * to sysctl is happening, result is new position if program overrode it,
- * initial value otherwise
- * @type: type of program to be executed
- *
- * Program is run when sysctl is being accessed, either read or written, and
- * can allow or deny such access.
- *
- * This function will return %-EPERM if an attached program is found and
- * returned value != 1 during execution. In all other cases 0 is returned.
- */
- int __cgroup_bpf_run_filter_sysctl(struct ctl_table_header *head,
- struct ctl_table *table, int write,
- char **buf, size_t *pcount, loff_t *ppos,
- enum bpf_attach_type type)
- {
- struct bpf_sysctl_kern ctx = {
- .head = head,
- .table = table,
- .write = write,
- .ppos = ppos,
- .cur_val = NULL,
- .cur_len = PAGE_SIZE,
- .new_val = NULL,
- .new_len = 0,
- .new_updated = 0,
- };
- struct cgroup *cgrp;
- loff_t pos = 0;
- int ret;
- ctx.cur_val = kmalloc_track_caller(ctx.cur_len, GFP_KERNEL);
- if (!ctx.cur_val ||
- table->proc_handler(table, 0, ctx.cur_val, &ctx.cur_len, &pos)) {
- /* Let BPF program decide how to proceed. */
- ctx.cur_len = 0;
- }
- if (write && *buf && *pcount) {
- /* BPF program should be able to override new value with a
- * buffer bigger than provided by user.
- */
- ctx.new_val = kmalloc_track_caller(PAGE_SIZE, GFP_KERNEL);
- ctx.new_len = min_t(size_t, PAGE_SIZE, *pcount);
- if (ctx.new_val) {
- memcpy(ctx.new_val, *buf, ctx.new_len);
- } else {
- /* Let BPF program decide how to proceed. */
- ctx.new_len = 0;
- }
- }
- rcu_read_lock();
- cgrp = task_dfl_cgroup(current);
- ret = BPF_PROG_RUN_ARRAY(cgrp->bpf.effective[type], &ctx, BPF_PROG_RUN);
- rcu_read_unlock();
- kfree(ctx.cur_val);
- if (ret == 1 && ctx.new_updated) {
- kfree(*buf);
- *buf = ctx.new_val;
- *pcount = ctx.new_len;
- } else {
- kfree(ctx.new_val);
- }
- return ret == 1 ? 0 : -EPERM;
- }
- #ifdef CONFIG_NET
- static bool __cgroup_bpf_prog_array_is_empty(struct cgroup *cgrp,
- enum bpf_attach_type attach_type)
- {
- struct bpf_prog_array *prog_array;
- bool empty;
- rcu_read_lock();
- prog_array = rcu_dereference(cgrp->bpf.effective[attach_type]);
- empty = bpf_prog_array_is_empty(prog_array);
- rcu_read_unlock();
- return empty;
- }
- static int sockopt_alloc_buf(struct bpf_sockopt_kern *ctx, int max_optlen)
- {
- if (unlikely(max_optlen < 0))
- return -EINVAL;
- if (unlikely(max_optlen > PAGE_SIZE)) {
- /* We don't expose optvals that are greater than PAGE_SIZE
- * to the BPF program.
- */
- max_optlen = PAGE_SIZE;
- }
- ctx->optval = kzalloc(max_optlen, GFP_USER);
- if (!ctx->optval)
- return -ENOMEM;
- ctx->optval_end = ctx->optval + max_optlen;
- return max_optlen;
- }
- static void sockopt_free_buf(struct bpf_sockopt_kern *ctx)
- {
- kfree(ctx->optval);
- }
- int __cgroup_bpf_run_filter_setsockopt(struct sock *sk, int *level,
- int *optname, char __user *optval,
- int *optlen, char **kernel_optval)
- {
- struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
- struct bpf_sockopt_kern ctx = {
- .sk = sk,
- .level = *level,
- .optname = *optname,
- };
- int ret, max_optlen;
- /* Opportunistic check to see whether we have any BPF program
- * attached to the hook so we don't waste time allocating
- * memory and locking the socket.
- */
- if (!cgroup_bpf_enabled ||
- __cgroup_bpf_prog_array_is_empty(cgrp, BPF_CGROUP_SETSOCKOPT))
- return 0;
- /* Allocate a bit more than the initial user buffer for
- * BPF program. The canonical use case is overriding
- * TCP_CONGESTION(nv) to TCP_CONGESTION(cubic).
- */
- max_optlen = max_t(int, 16, *optlen);
- max_optlen = sockopt_alloc_buf(&ctx, max_optlen);
- if (max_optlen < 0)
- return max_optlen;
- ctx.optlen = *optlen;
- if (copy_from_user(ctx.optval, optval, min(*optlen, max_optlen)) != 0) {
- ret = -EFAULT;
- goto out;
- }
- lock_sock(sk);
- ret = BPF_PROG_RUN_ARRAY(cgrp->bpf.effective[BPF_CGROUP_SETSOCKOPT],
- &ctx, BPF_PROG_RUN);
- release_sock(sk);
- if (!ret) {
- ret = -EPERM;
- goto out;
- }
- if (ctx.optlen == -1) {
- /* optlen set to -1, bypass kernel */
- ret = 1;
- } else if (ctx.optlen > max_optlen || ctx.optlen < -1) {
- /* optlen is out of bounds */
- ret = -EFAULT;
- } else {
- /* optlen within bounds, run kernel handler */
- ret = 0;
- /* export any potential modifications */
- *level = ctx.level;
- *optname = ctx.optname;
- /* optlen == 0 from BPF indicates that we should
- * use original userspace data.
- */
- if (ctx.optlen != 0) {
- *optlen = ctx.optlen;
- *kernel_optval = ctx.optval;
- /* export and don't free sockopt buf */
- return 0;
- }
- }
- out:
- sockopt_free_buf(&ctx);
- return ret;
- }
- int __cgroup_bpf_run_filter_getsockopt(struct sock *sk, int level,
- int optname, char __user *optval,
- int __user *optlen, int max_optlen,
- int retval)
- {
- struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
- struct bpf_sockopt_kern ctx = {
- .sk = sk,
- .level = level,
- .optname = optname,
- .retval = retval,
- };
- int ret;
- /* Opportunistic check to see whether we have any BPF program
- * attached to the hook so we don't waste time allocating
- * memory and locking the socket.
- */
- if (!cgroup_bpf_enabled ||
- __cgroup_bpf_prog_array_is_empty(cgrp, BPF_CGROUP_GETSOCKOPT))
- return retval;
- ctx.optlen = max_optlen;
- max_optlen = sockopt_alloc_buf(&ctx, max_optlen);
- if (max_optlen < 0)
- return max_optlen;
- if (!retval) {
- /* If kernel getsockopt finished successfully,
- * copy whatever was returned to the user back
- * into our temporary buffer. Set optlen to the
- * one that kernel returned as well to let
- * BPF programs inspect the value.
- */
- if (get_user(ctx.optlen, optlen)) {
- ret = -EFAULT;
- goto out;
- }
- if (ctx.optlen < 0) {
- ret = -EFAULT;
- goto out;
- }
- if (copy_from_user(ctx.optval, optval,
- min(ctx.optlen, max_optlen)) != 0) {
- ret = -EFAULT;
- goto out;
- }
- }
- lock_sock(sk);
- ret = BPF_PROG_RUN_ARRAY(cgrp->bpf.effective[BPF_CGROUP_GETSOCKOPT],
- &ctx, BPF_PROG_RUN);
- release_sock(sk);
- if (!ret) {
- ret = -EPERM;
- goto out;
- }
- if (ctx.optlen > max_optlen || ctx.optlen < 0) {
- ret = -EFAULT;
- goto out;
- }
- /* BPF programs only allowed to set retval to 0, not some
- * arbitrary value.
- */
- if (ctx.retval != 0 && ctx.retval != retval) {
- ret = -EFAULT;
- goto out;
- }
- if (ctx.optlen != 0) {
- if (copy_to_user(optval, ctx.optval, ctx.optlen) ||
- put_user(ctx.optlen, optlen)) {
- ret = -EFAULT;
- goto out;
- }
- }
- ret = ctx.retval;
- out:
- sockopt_free_buf(&ctx);
- return ret;
- }
- #endif
- static ssize_t sysctl_cpy_dir(const struct ctl_dir *dir, char **bufp,
- size_t *lenp)
- {
- ssize_t tmp_ret = 0, ret;
- if (dir->header.parent) {
- tmp_ret = sysctl_cpy_dir(dir->header.parent, bufp, lenp);
- if (tmp_ret < 0)
- return tmp_ret;
- }
- ret = strscpy(*bufp, dir->header.ctl_table[0].procname, *lenp);
- if (ret < 0)
- return ret;
- *bufp += ret;
- *lenp -= ret;
- ret += tmp_ret;
- /* Avoid leading slash. */
- if (!ret)
- return ret;
- tmp_ret = strscpy(*bufp, "/", *lenp);
- if (tmp_ret < 0)
- return tmp_ret;
- *bufp += tmp_ret;
- *lenp -= tmp_ret;
- return ret + tmp_ret;
- }
- BPF_CALL_4(bpf_sysctl_get_name, struct bpf_sysctl_kern *, ctx, char *, buf,
- size_t, buf_len, u64, flags)
- {
- ssize_t tmp_ret = 0, ret;
- if (!buf)
- return -EINVAL;
- if (!(flags & BPF_F_SYSCTL_BASE_NAME)) {
- if (!ctx->head)
- return -EINVAL;
- tmp_ret = sysctl_cpy_dir(ctx->head->parent, &buf, &buf_len);
- if (tmp_ret < 0)
- return tmp_ret;
- }
- ret = strscpy(buf, ctx->table->procname, buf_len);
- return ret < 0 ? ret : tmp_ret + ret;
- }
- static const struct bpf_func_proto bpf_sysctl_get_name_proto = {
- .func = bpf_sysctl_get_name,
- .gpl_only = false,
- .ret_type = RET_INTEGER,
- .arg1_type = ARG_PTR_TO_CTX,
- .arg2_type = ARG_PTR_TO_MEM,
- .arg3_type = ARG_CONST_SIZE,
- .arg4_type = ARG_ANYTHING,
- };
- static int copy_sysctl_value(char *dst, size_t dst_len, char *src,
- size_t src_len)
- {
- if (!dst)
- return -EINVAL;
- if (!dst_len)
- return -E2BIG;
- if (!src || !src_len) {
- memset(dst, 0, dst_len);
- return -EINVAL;
- }
- memcpy(dst, src, min(dst_len, src_len));
- if (dst_len > src_len) {
- memset(dst + src_len, '\0', dst_len - src_len);
- return src_len;
- }
- dst[dst_len - 1] = '\0';
- return -E2BIG;
- }
- BPF_CALL_3(bpf_sysctl_get_current_value, struct bpf_sysctl_kern *, ctx,
- char *, buf, size_t, buf_len)
- {
- return copy_sysctl_value(buf, buf_len, ctx->cur_val, ctx->cur_len);
- }
- static const struct bpf_func_proto bpf_sysctl_get_current_value_proto = {
- .func = bpf_sysctl_get_current_value,
- .gpl_only = false,
- .ret_type = RET_INTEGER,
- .arg1_type = ARG_PTR_TO_CTX,
- .arg2_type = ARG_PTR_TO_UNINIT_MEM,
- .arg3_type = ARG_CONST_SIZE,
- };
- BPF_CALL_3(bpf_sysctl_get_new_value, struct bpf_sysctl_kern *, ctx, char *, buf,
- size_t, buf_len)
- {
- if (!ctx->write) {
- if (buf && buf_len)
- memset(buf, '\0', buf_len);
- return -EINVAL;
- }
- return copy_sysctl_value(buf, buf_len, ctx->new_val, ctx->new_len);
- }
- static const struct bpf_func_proto bpf_sysctl_get_new_value_proto = {
- .func = bpf_sysctl_get_new_value,
- .gpl_only = false,
- .ret_type = RET_INTEGER,
- .arg1_type = ARG_PTR_TO_CTX,
- .arg2_type = ARG_PTR_TO_UNINIT_MEM,
- .arg3_type = ARG_CONST_SIZE,
- };
- BPF_CALL_3(bpf_sysctl_set_new_value, struct bpf_sysctl_kern *, ctx,
- const char *, buf, size_t, buf_len)
- {
- if (!ctx->write || !ctx->new_val || !ctx->new_len || !buf || !buf_len)
- return -EINVAL;
- if (buf_len > PAGE_SIZE - 1)
- return -E2BIG;
- memcpy(ctx->new_val, buf, buf_len);
- ctx->new_len = buf_len;
- ctx->new_updated = 1;
- return 0;
- }
- static const struct bpf_func_proto bpf_sysctl_set_new_value_proto = {
- .func = bpf_sysctl_set_new_value,
- .gpl_only = false,
- .ret_type = RET_INTEGER,
- .arg1_type = ARG_PTR_TO_CTX,
- .arg2_type = ARG_PTR_TO_MEM,
- .arg3_type = ARG_CONST_SIZE,
- };
- static const struct bpf_func_proto *
- sysctl_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
- {
- switch (func_id) {
- case BPF_FUNC_strtol:
- return &bpf_strtol_proto;
- case BPF_FUNC_strtoul:
- return &bpf_strtoul_proto;
- case BPF_FUNC_sysctl_get_name:
- return &bpf_sysctl_get_name_proto;
- case BPF_FUNC_sysctl_get_current_value:
- return &bpf_sysctl_get_current_value_proto;
- case BPF_FUNC_sysctl_get_new_value:
- return &bpf_sysctl_get_new_value_proto;
- case BPF_FUNC_sysctl_set_new_value:
- return &bpf_sysctl_set_new_value_proto;
- default:
- return cgroup_base_func_proto(func_id, prog);
- }
- }
- static bool sysctl_is_valid_access(int off, int size, enum bpf_access_type type,
- const struct bpf_prog *prog,
- struct bpf_insn_access_aux *info)
- {
- const int size_default = sizeof(__u32);
- if (off < 0 || off + size > sizeof(struct bpf_sysctl) || off % size)
- return false;
- switch (off) {
- case bpf_ctx_range(struct bpf_sysctl, write):
- if (type != BPF_READ)
- return false;
- bpf_ctx_record_field_size(info, size_default);
- return bpf_ctx_narrow_access_ok(off, size, size_default);
- case bpf_ctx_range(struct bpf_sysctl, file_pos):
- if (type == BPF_READ) {
- bpf_ctx_record_field_size(info, size_default);
- return bpf_ctx_narrow_access_ok(off, size, size_default);
- } else {
- return size == size_default;
- }
- default:
- return false;
- }
- }
- static u32 sysctl_convert_ctx_access(enum bpf_access_type type,
- const struct bpf_insn *si,
- struct bpf_insn *insn_buf,
- struct bpf_prog *prog, u32 *target_size)
- {
- struct bpf_insn *insn = insn_buf;
- u32 read_size;
- switch (si->off) {
- case offsetof(struct bpf_sysctl, write):
- *insn++ = BPF_LDX_MEM(
- BPF_SIZE(si->code), si->dst_reg, si->src_reg,
- bpf_target_off(struct bpf_sysctl_kern, write,
- sizeof_field(struct bpf_sysctl_kern,
- write),
- target_size));
- break;
- case offsetof(struct bpf_sysctl, file_pos):
- /* ppos is a pointer so it should be accessed via indirect
- * loads and stores. Also for stores additional temporary
- * register is used since neither src_reg nor dst_reg can be
- * overridden.
- */
- if (type == BPF_WRITE) {
- int treg = BPF_REG_9;
- if (si->src_reg == treg || si->dst_reg == treg)
- --treg;
- if (si->src_reg == treg || si->dst_reg == treg)
- --treg;
- *insn++ = BPF_STX_MEM(
- BPF_DW, si->dst_reg, treg,
- offsetof(struct bpf_sysctl_kern, tmp_reg));
- *insn++ = BPF_LDX_MEM(
- BPF_FIELD_SIZEOF(struct bpf_sysctl_kern, ppos),
- treg, si->dst_reg,
- offsetof(struct bpf_sysctl_kern, ppos));
- *insn++ = BPF_STX_MEM(
- BPF_SIZEOF(u32), treg, si->src_reg,
- bpf_ctx_narrow_access_offset(
- 0, sizeof(u32), sizeof(loff_t)));
- *insn++ = BPF_LDX_MEM(
- BPF_DW, treg, si->dst_reg,
- offsetof(struct bpf_sysctl_kern, tmp_reg));
- } else {
- *insn++ = BPF_LDX_MEM(
- BPF_FIELD_SIZEOF(struct bpf_sysctl_kern, ppos),
- si->dst_reg, si->src_reg,
- offsetof(struct bpf_sysctl_kern, ppos));
- read_size = bpf_size_to_bytes(BPF_SIZE(si->code));
- *insn++ = BPF_LDX_MEM(
- BPF_SIZE(si->code), si->dst_reg, si->dst_reg,
- bpf_ctx_narrow_access_offset(
- 0, read_size, sizeof(loff_t)));
- }
- *target_size = sizeof(u32);
- break;
- }
- return insn - insn_buf;
- }
- const struct bpf_verifier_ops cg_sysctl_verifier_ops = {
- .get_func_proto = sysctl_func_proto,
- .is_valid_access = sysctl_is_valid_access,
- .convert_ctx_access = sysctl_convert_ctx_access,
- };
- const struct bpf_prog_ops cg_sysctl_prog_ops = {
- };
- static const struct bpf_func_proto *
- cg_sockopt_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
- {
- switch (func_id) {
- #ifdef CONFIG_NET
- case BPF_FUNC_sk_storage_get:
- return &bpf_sk_storage_get_proto;
- case BPF_FUNC_sk_storage_delete:
- return &bpf_sk_storage_delete_proto;
- #endif
- #ifdef CONFIG_INET
- case BPF_FUNC_tcp_sock:
- return &bpf_tcp_sock_proto;
- #endif
- default:
- return cgroup_base_func_proto(func_id, prog);
- }
- }
- static bool cg_sockopt_is_valid_access(int off, int size,
- enum bpf_access_type type,
- const struct bpf_prog *prog,
- struct bpf_insn_access_aux *info)
- {
- const int size_default = sizeof(__u32);
- if (off < 0 || off >= sizeof(struct bpf_sockopt))
- return false;
- if (off % size != 0)
- return false;
- if (type == BPF_WRITE) {
- switch (off) {
- case offsetof(struct bpf_sockopt, retval):
- if (size != size_default)
- return false;
- return prog->expected_attach_type ==
- BPF_CGROUP_GETSOCKOPT;
- case offsetof(struct bpf_sockopt, optname):
- fallthrough;
- case offsetof(struct bpf_sockopt, level):
- if (size != size_default)
- return false;
- return prog->expected_attach_type ==
- BPF_CGROUP_SETSOCKOPT;
- case offsetof(struct bpf_sockopt, optlen):
- return size == size_default;
- default:
- return false;
- }
- }
- switch (off) {
- case offsetof(struct bpf_sockopt, sk):
- if (size != sizeof(__u64))
- return false;
- info->reg_type = PTR_TO_SOCKET;
- break;
- case offsetof(struct bpf_sockopt, optval):
- if (size != sizeof(__u64))
- return false;
- info->reg_type = PTR_TO_PACKET;
- break;
- case offsetof(struct bpf_sockopt, optval_end):
- if (size != sizeof(__u64))
- return false;
- info->reg_type = PTR_TO_PACKET_END;
- break;
- case offsetof(struct bpf_sockopt, retval):
- if (size != size_default)
- return false;
- return prog->expected_attach_type == BPF_CGROUP_GETSOCKOPT;
- default:
- if (size != size_default)
- return false;
- break;
- }
- return true;
- }
- #define CG_SOCKOPT_ACCESS_FIELD(T, F) \
- T(BPF_FIELD_SIZEOF(struct bpf_sockopt_kern, F), \
- si->dst_reg, si->src_reg, \
- offsetof(struct bpf_sockopt_kern, F))
- static u32 cg_sockopt_convert_ctx_access(enum bpf_access_type type,
- const struct bpf_insn *si,
- struct bpf_insn *insn_buf,
- struct bpf_prog *prog,
- u32 *target_size)
- {
- struct bpf_insn *insn = insn_buf;
- switch (si->off) {
- case offsetof(struct bpf_sockopt, sk):
- *insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_LDX_MEM, sk);
- break;
- case offsetof(struct bpf_sockopt, level):
- if (type == BPF_WRITE)
- *insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_STX_MEM, level);
- else
- *insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_LDX_MEM, level);
- break;
- case offsetof(struct bpf_sockopt, optname):
- if (type == BPF_WRITE)
- *insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_STX_MEM, optname);
- else
- *insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_LDX_MEM, optname);
- break;
- case offsetof(struct bpf_sockopt, optlen):
- if (type == BPF_WRITE)
- *insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_STX_MEM, optlen);
- else
- *insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_LDX_MEM, optlen);
- break;
- case offsetof(struct bpf_sockopt, retval):
- if (type == BPF_WRITE)
- *insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_STX_MEM, retval);
- else
- *insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_LDX_MEM, retval);
- break;
- case offsetof(struct bpf_sockopt, optval):
- *insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_LDX_MEM, optval);
- break;
- case offsetof(struct bpf_sockopt, optval_end):
- *insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_LDX_MEM, optval_end);
- break;
- }
- return insn - insn_buf;
- }
- static int cg_sockopt_get_prologue(struct bpf_insn *insn_buf,
- bool direct_write,
- const struct bpf_prog *prog)
- {
- /* Nothing to do for sockopt argument. The data is kzalloc'ated.
- */
- return 0;
- }
- const struct bpf_verifier_ops cg_sockopt_verifier_ops = {
- .get_func_proto = cg_sockopt_func_proto,
- .is_valid_access = cg_sockopt_is_valid_access,
- .convert_ctx_access = cg_sockopt_convert_ctx_access,
- .gen_prologue = cg_sockopt_get_prologue,
- };
- const struct bpf_prog_ops cg_sockopt_prog_ops = {
- };
|