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2055 lines
52 KiB
2055 lines
52 KiB
// SPDX-License-Identifier: GPL-2.0-only |
|
/* |
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* Functions to manage eBPF programs attached to cgroups |
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* |
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* Copyright (c) 2016 Daniel Mack |
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*/ |
|
|
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#include <linux/kernel.h> |
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#include <linux/atomic.h> |
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#include <linux/cgroup.h> |
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#include <linux/filter.h> |
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#include <linux/slab.h> |
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#include <linux/sysctl.h> |
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#include <linux/string.h> |
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#include <linux/bpf.h> |
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#include <linux/bpf-cgroup.h> |
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#include <net/sock.h> |
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#include <net/bpf_sk_storage.h> |
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|
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#include "../cgroup/cgroup-internal.h" |
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|
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DEFINE_STATIC_KEY_ARRAY_FALSE(cgroup_bpf_enabled_key, MAX_CGROUP_BPF_ATTACH_TYPE); |
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EXPORT_SYMBOL(cgroup_bpf_enabled_key); |
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|
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void cgroup_bpf_offline(struct cgroup *cgrp) |
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{ |
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cgroup_get(cgrp); |
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percpu_ref_kill(&cgrp->bpf.refcnt); |
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} |
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|
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static void bpf_cgroup_storages_free(struct bpf_cgroup_storage *storages[]) |
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{ |
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enum bpf_cgroup_storage_type stype; |
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|
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for_each_cgroup_storage_type(stype) |
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bpf_cgroup_storage_free(storages[stype]); |
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} |
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|
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static int bpf_cgroup_storages_alloc(struct bpf_cgroup_storage *storages[], |
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struct bpf_cgroup_storage *new_storages[], |
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enum bpf_attach_type type, |
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struct bpf_prog *prog, |
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struct cgroup *cgrp) |
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{ |
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enum bpf_cgroup_storage_type stype; |
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struct bpf_cgroup_storage_key key; |
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struct bpf_map *map; |
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|
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key.cgroup_inode_id = cgroup_id(cgrp); |
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key.attach_type = type; |
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|
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for_each_cgroup_storage_type(stype) { |
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map = prog->aux->cgroup_storage[stype]; |
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if (!map) |
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continue; |
|
|
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storages[stype] = cgroup_storage_lookup((void *)map, &key, false); |
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if (storages[stype]) |
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continue; |
|
|
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storages[stype] = bpf_cgroup_storage_alloc(prog, stype); |
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if (IS_ERR(storages[stype])) { |
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bpf_cgroup_storages_free(new_storages); |
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return -ENOMEM; |
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} |
|
|
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new_storages[stype] = storages[stype]; |
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} |
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|
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return 0; |
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} |
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|
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static void bpf_cgroup_storages_assign(struct bpf_cgroup_storage *dst[], |
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struct bpf_cgroup_storage *src[]) |
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{ |
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enum bpf_cgroup_storage_type stype; |
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|
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for_each_cgroup_storage_type(stype) |
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dst[stype] = src[stype]; |
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} |
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|
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static void bpf_cgroup_storages_link(struct bpf_cgroup_storage *storages[], |
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struct cgroup *cgrp, |
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enum bpf_attach_type attach_type) |
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{ |
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enum bpf_cgroup_storage_type stype; |
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|
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for_each_cgroup_storage_type(stype) |
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bpf_cgroup_storage_link(storages[stype], cgrp, attach_type); |
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} |
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|
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/* Called when bpf_cgroup_link is auto-detached from dying cgroup. |
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* It drops cgroup and bpf_prog refcounts, and marks bpf_link as defunct. It |
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* doesn't free link memory, which will eventually be done by bpf_link's |
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* release() callback, when its last FD is closed. |
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*/ |
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static void bpf_cgroup_link_auto_detach(struct bpf_cgroup_link *link) |
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{ |
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cgroup_put(link->cgroup); |
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link->cgroup = NULL; |
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} |
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|
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/** |
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* cgroup_bpf_release() - put references of all bpf programs and |
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* release all cgroup bpf data |
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* @work: work structure embedded into the cgroup to modify |
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*/ |
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static void cgroup_bpf_release(struct work_struct *work) |
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{ |
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struct cgroup *p, *cgrp = container_of(work, struct cgroup, |
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bpf.release_work); |
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struct bpf_prog_array *old_array; |
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struct list_head *storages = &cgrp->bpf.storages; |
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struct bpf_cgroup_storage *storage, *stmp; |
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|
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unsigned int atype; |
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|
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mutex_lock(&cgroup_mutex); |
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|
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for (atype = 0; atype < ARRAY_SIZE(cgrp->bpf.progs); atype++) { |
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struct list_head *progs = &cgrp->bpf.progs[atype]; |
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struct bpf_prog_list *pl, *pltmp; |
|
|
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list_for_each_entry_safe(pl, pltmp, progs, node) { |
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list_del(&pl->node); |
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if (pl->prog) |
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bpf_prog_put(pl->prog); |
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if (pl->link) |
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bpf_cgroup_link_auto_detach(pl->link); |
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kfree(pl); |
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static_branch_dec(&cgroup_bpf_enabled_key[atype]); |
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} |
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old_array = rcu_dereference_protected( |
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cgrp->bpf.effective[atype], |
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lockdep_is_held(&cgroup_mutex)); |
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bpf_prog_array_free(old_array); |
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} |
|
|
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list_for_each_entry_safe(storage, stmp, storages, list_cg) { |
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bpf_cgroup_storage_unlink(storage); |
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bpf_cgroup_storage_free(storage); |
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} |
|
|
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mutex_unlock(&cgroup_mutex); |
|
|
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for (p = cgroup_parent(cgrp); p; p = cgroup_parent(p)) |
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cgroup_bpf_put(p); |
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|
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percpu_ref_exit(&cgrp->bpf.refcnt); |
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cgroup_put(cgrp); |
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} |
|
|
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/** |
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* cgroup_bpf_release_fn() - callback used to schedule releasing |
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* of bpf cgroup data |
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* @ref: percpu ref counter structure |
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*/ |
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static void cgroup_bpf_release_fn(struct percpu_ref *ref) |
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{ |
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struct cgroup *cgrp = container_of(ref, struct cgroup, bpf.refcnt); |
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|
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INIT_WORK(&cgrp->bpf.release_work, cgroup_bpf_release); |
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queue_work(system_wq, &cgrp->bpf.release_work); |
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} |
|
|
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/* Get underlying bpf_prog of bpf_prog_list entry, regardless if it's through |
|
* link or direct prog. |
|
*/ |
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static struct bpf_prog *prog_list_prog(struct bpf_prog_list *pl) |
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{ |
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if (pl->prog) |
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return pl->prog; |
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if (pl->link) |
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return pl->link->link.prog; |
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return NULL; |
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} |
|
|
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/* count number of elements in the list. |
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* it's slow but the list cannot be long |
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*/ |
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static u32 prog_list_length(struct list_head *head) |
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{ |
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struct bpf_prog_list *pl; |
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u32 cnt = 0; |
|
|
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list_for_each_entry(pl, head, node) { |
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if (!prog_list_prog(pl)) |
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continue; |
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cnt++; |
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} |
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return cnt; |
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} |
|
|
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/* if parent has non-overridable prog attached, |
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* disallow attaching new programs to the descendent cgroup. |
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* if parent has overridable or multi-prog, allow attaching |
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*/ |
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static bool hierarchy_allows_attach(struct cgroup *cgrp, |
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enum cgroup_bpf_attach_type atype) |
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{ |
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struct cgroup *p; |
|
|
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p = cgroup_parent(cgrp); |
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if (!p) |
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return true; |
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do { |
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u32 flags = p->bpf.flags[atype]; |
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u32 cnt; |
|
|
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if (flags & BPF_F_ALLOW_MULTI) |
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return true; |
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cnt = prog_list_length(&p->bpf.progs[atype]); |
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WARN_ON_ONCE(cnt > 1); |
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if (cnt == 1) |
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return !!(flags & BPF_F_ALLOW_OVERRIDE); |
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p = cgroup_parent(p); |
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} while (p); |
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return true; |
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} |
|
|
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/* compute a chain of effective programs for a given cgroup: |
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* start from the list of programs in this cgroup and add |
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* all parent programs. |
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* Note that parent's F_ALLOW_OVERRIDE-type program is yielding |
|
* to programs in this cgroup |
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*/ |
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static int compute_effective_progs(struct cgroup *cgrp, |
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enum cgroup_bpf_attach_type atype, |
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struct bpf_prog_array **array) |
|
{ |
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struct bpf_prog_array_item *item; |
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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[atype] & BPF_F_ALLOW_MULTI)) |
|
cnt += prog_list_length(&p->bpf.progs[atype]); |
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p = cgroup_parent(p); |
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} while (p); |
|
|
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progs = bpf_prog_array_alloc(cnt, GFP_KERNEL); |
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if (!progs) |
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return -ENOMEM; |
|
|
|
/* populate the array with effective progs */ |
|
cnt = 0; |
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p = cgrp; |
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do { |
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if (cnt > 0 && !(p->bpf.flags[atype] & BPF_F_ALLOW_MULTI)) |
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continue; |
|
|
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list_for_each_entry(pl, &p->bpf.progs[atype], node) { |
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if (!prog_list_prog(pl)) |
|
continue; |
|
|
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item = &progs->items[cnt]; |
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item->prog = prog_list_prog(pl); |
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bpf_cgroup_storages_assign(item->cgroup_storage, |
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pl->storage); |
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cnt++; |
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} |
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} while ((p = cgroup_parent(p))); |
|
|
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*array = progs; |
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return 0; |
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} |
|
|
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static void activate_effective_progs(struct cgroup *cgrp, |
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enum cgroup_bpf_attach_type atype, |
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struct bpf_prog_array *old_array) |
|
{ |
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old_array = rcu_replace_pointer(cgrp->bpf.effective[atype], old_array, |
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lockdep_is_held(&cgroup_mutex)); |
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/* free prog array after grace period, since __cgroup_bpf_run_*() |
|
* might be still walking the array |
|
*/ |
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bpf_prog_array_free(old_array); |
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} |
|
|
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/** |
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* cgroup_bpf_inherit() - inherit effective programs from parent |
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* @cgrp: the cgroup to modify |
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*/ |
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int cgroup_bpf_inherit(struct cgroup *cgrp) |
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{ |
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/* has to use marco instead of const int, since compiler thinks |
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* that array below is variable length |
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*/ |
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#define NR ARRAY_SIZE(cgrp->bpf.effective) |
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struct bpf_prog_array *arrays[NR] = {}; |
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struct cgroup *p; |
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int ret, i; |
|
|
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ret = percpu_ref_init(&cgrp->bpf.refcnt, cgroup_bpf_release_fn, 0, |
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GFP_KERNEL); |
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if (ret) |
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return ret; |
|
|
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for (p = cgroup_parent(cgrp); p; p = cgroup_parent(p)) |
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cgroup_bpf_get(p); |
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|
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for (i = 0; i < NR; i++) |
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INIT_LIST_HEAD(&cgrp->bpf.progs[i]); |
|
|
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INIT_LIST_HEAD(&cgrp->bpf.storages); |
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|
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for (i = 0; i < NR; i++) |
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if (compute_effective_progs(cgrp, i, &arrays[i])) |
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goto cleanup; |
|
|
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for (i = 0; i < NR; i++) |
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activate_effective_progs(cgrp, i, arrays[i]); |
|
|
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return 0; |
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cleanup: |
|
for (i = 0; i < NR; i++) |
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bpf_prog_array_free(arrays[i]); |
|
|
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for (p = cgroup_parent(cgrp); p; p = cgroup_parent(p)) |
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cgroup_bpf_put(p); |
|
|
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percpu_ref_exit(&cgrp->bpf.refcnt); |
|
|
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return -ENOMEM; |
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} |
|
|
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static int update_effective_progs(struct cgroup *cgrp, |
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enum cgroup_bpf_attach_type atype) |
|
{ |
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struct cgroup_subsys_state *css; |
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int err; |
|
|
|
/* allocate and recompute effective prog arrays */ |
|
css_for_each_descendant_pre(css, &cgrp->self) { |
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struct cgroup *desc = container_of(css, struct cgroup, self); |
|
|
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if (percpu_ref_is_zero(&desc->bpf.refcnt)) |
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continue; |
|
|
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err = compute_effective_progs(desc, atype, &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, atype, 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 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] = {}; |
|
enum cgroup_bpf_attach_type atype; |
|
struct bpf_prog_list *pl; |
|
struct list_head *progs; |
|
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; |
|
|
|
atype = to_cgroup_bpf_attach_type(type); |
|
if (atype < 0) |
|
return -EINVAL; |
|
|
|
progs = &cgrp->bpf.progs[atype]; |
|
|
|
if (!hierarchy_allows_attach(cgrp, atype)) |
|
return -EPERM; |
|
|
|
if (!list_empty(progs) && cgrp->bpf.flags[atype] != 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[atype] = saved_flags; |
|
|
|
err = update_effective_progs(cgrp, atype); |
|
if (err) |
|
goto cleanup; |
|
|
|
if (old_prog) |
|
bpf_prog_put(old_prog); |
|
else |
|
static_branch_inc(&cgroup_bpf_enabled_key[atype]); |
|
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 cgroup_bpf_attach_type atype, |
|
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[atype] & BPF_F_ALLOW_MULTI)) |
|
continue; |
|
|
|
head = &cg->bpf.progs[atype]; |
|
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[atype], |
|
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) |
|
{ |
|
enum cgroup_bpf_attach_type atype; |
|
struct bpf_prog *old_prog; |
|
struct bpf_prog_list *pl; |
|
struct list_head *progs; |
|
bool found = false; |
|
|
|
atype = to_cgroup_bpf_attach_type(link->type); |
|
if (atype < 0) |
|
return -EINVAL; |
|
|
|
progs = &cgrp->bpf.progs[atype]; |
|
|
|
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, atype, 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) |
|
{ |
|
enum cgroup_bpf_attach_type atype; |
|
struct bpf_prog *old_prog; |
|
struct bpf_prog_list *pl; |
|
struct list_head *progs; |
|
u32 flags; |
|
int err; |
|
|
|
atype = to_cgroup_bpf_attach_type(type); |
|
if (atype < 0) |
|
return -EINVAL; |
|
|
|
progs = &cgrp->bpf.progs[atype]; |
|
flags = cgrp->bpf.flags[atype]; |
|
|
|
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, atype); |
|
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[atype] = 0; |
|
if (old_prog) |
|
bpf_prog_put(old_prog); |
|
static_branch_dec(&cgroup_bpf_enabled_key[atype]); |
|
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; |
|
enum cgroup_bpf_attach_type atype; |
|
struct bpf_prog_array *effective; |
|
struct list_head *progs; |
|
struct bpf_prog *prog; |
|
int cnt, ret = 0, i; |
|
u32 flags; |
|
|
|
atype = to_cgroup_bpf_attach_type(type); |
|
if (atype < 0) |
|
return -EINVAL; |
|
|
|
progs = &cgrp->bpf.progs[atype]; |
|
flags = cgrp->bpf.flags[atype]; |
|
|
|
effective = rcu_dereference_protected(cgrp->bpf.effective[atype], |
|
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 cgroup_bpf_attach_type atype) |
|
{ |
|
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 (atype == CGROUP_INET_EGRESS) { |
|
ret = BPF_PROG_CGROUP_INET_EGRESS_RUN_ARRAY( |
|
cgrp->bpf.effective[atype], skb, __bpf_prog_run_save_cb); |
|
} else { |
|
ret = BPF_PROG_RUN_ARRAY_CG(cgrp->bpf.effective[atype], 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 cgroup_bpf_attach_type atype) |
|
{ |
|
struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data); |
|
int ret; |
|
|
|
ret = BPF_PROG_RUN_ARRAY_CG(cgrp->bpf.effective[atype], 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 |
|
* @flags: Pointer to u32 which contains higher bits of BPF program |
|
* return value (OR'ed together). |
|
* |
|
* 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 cgroup_bpf_attach_type atype, |
|
void *t_ctx, |
|
u32 *flags) |
|
{ |
|
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_CG_FLAGS(cgrp->bpf.effective[atype], &ctx, |
|
bpf_prog_run, flags); |
|
|
|
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 cgroup_bpf_attach_type atype) |
|
{ |
|
struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data); |
|
int ret; |
|
|
|
ret = BPF_PROG_RUN_ARRAY_CG(cgrp->bpf.effective[atype], 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 cgroup_bpf_attach_type atype) |
|
{ |
|
struct cgroup *cgrp; |
|
struct bpf_cgroup_dev_ctx ctx = { |
|
.access_type = (access << 16) | dev_type, |
|
.major = major, |
|
.minor = minor, |
|
}; |
|
int allow; |
|
|
|
rcu_read_lock(); |
|
cgrp = task_dfl_cgroup(current); |
|
allow = BPF_PROG_RUN_ARRAY_CG(cgrp->bpf.effective[atype], &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 cgroup_bpf_attach_type atype) |
|
{ |
|
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_CG(cgrp->bpf.effective[atype], &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 cgroup_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, |
|
struct bpf_sockopt_buf *buf) |
|
{ |
|
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; |
|
} |
|
|
|
if (max_optlen <= sizeof(buf->data)) { |
|
/* When the optval fits into BPF_SOCKOPT_KERN_BUF_SIZE |
|
* bytes avoid the cost of kzalloc. |
|
*/ |
|
ctx->optval = buf->data; |
|
ctx->optval_end = ctx->optval + max_optlen; |
|
return max_optlen; |
|
} |
|
|
|
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, |
|
struct bpf_sockopt_buf *buf) |
|
{ |
|
if (ctx->optval == buf->data) |
|
return; |
|
kfree(ctx->optval); |
|
} |
|
|
|
static bool sockopt_buf_allocated(struct bpf_sockopt_kern *ctx, |
|
struct bpf_sockopt_buf *buf) |
|
{ |
|
return ctx->optval != buf->data; |
|
} |
|
|
|
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_buf buf = {}; |
|
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_prog_array_is_empty(cgrp, 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, &buf); |
|
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_CG(cgrp->bpf.effective[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; |
|
/* We've used bpf_sockopt_kern->buf as an intermediary |
|
* storage, but the BPF program indicates that we need |
|
* to pass this data to the kernel setsockopt handler. |
|
* No way to export on-stack buf, have to allocate a |
|
* new buffer. |
|
*/ |
|
if (!sockopt_buf_allocated(&ctx, &buf)) { |
|
void *p = kmalloc(ctx.optlen, GFP_USER); |
|
|
|
if (!p) { |
|
ret = -ENOMEM; |
|
goto out; |
|
} |
|
memcpy(p, ctx.optval, ctx.optlen); |
|
*kernel_optval = p; |
|
} else { |
|
*kernel_optval = ctx.optval; |
|
} |
|
/* export and don't free sockopt buf */ |
|
return 0; |
|
} |
|
} |
|
|
|
out: |
|
sockopt_free_buf(&ctx, &buf); |
|
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_buf buf = {}; |
|
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_prog_array_is_empty(cgrp, CGROUP_GETSOCKOPT)) |
|
return retval; |
|
|
|
ctx.optlen = max_optlen; |
|
|
|
max_optlen = sockopt_alloc_buf(&ctx, max_optlen, &buf); |
|
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_CG(cgrp->bpf.effective[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, &buf); |
|
return ret; |
|
} |
|
|
|
int __cgroup_bpf_run_filter_getsockopt_kern(struct sock *sk, int level, |
|
int optname, void *optval, |
|
int *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, |
|
.optlen = *optlen, |
|
.optval = optval, |
|
.optval_end = optval + *optlen, |
|
}; |
|
int ret; |
|
|
|
/* Note that __cgroup_bpf_run_filter_getsockopt doesn't copy |
|
* user data back into BPF buffer when reval != 0. This is |
|
* done as an optimization to avoid extra copy, assuming |
|
* kernel won't populate the data in case of an error. |
|
* Here we always pass the data and memset() should |
|
* be called if that data shouldn't be "exported". |
|
*/ |
|
|
|
ret = BPF_PROG_RUN_ARRAY_CG(cgrp->bpf.effective[CGROUP_GETSOCKOPT], |
|
&ctx, bpf_prog_run); |
|
if (!ret) |
|
return -EPERM; |
|
|
|
if (ctx.optlen > *optlen) |
|
return -EFAULT; |
|
|
|
/* BPF programs only allowed to set retval to 0, not some |
|
* arbitrary value. |
|
*/ |
|
if (ctx.retval != 0 && ctx.retval != retval) |
|
return -EFAULT; |
|
|
|
/* BPF programs can shrink the buffer, export the modifications. |
|
*/ |
|
if (ctx.optlen != 0) |
|
*optlen = ctx.optlen; |
|
|
|
return ctx.retval; |
|
} |
|
#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 = { |
|
}; |
|
|
|
#ifdef CONFIG_NET |
|
BPF_CALL_1(bpf_get_netns_cookie_sockopt, struct bpf_sockopt_kern *, ctx) |
|
{ |
|
const struct net *net = ctx ? sock_net(ctx->sk) : &init_net; |
|
|
|
return net->net_cookie; |
|
} |
|
|
|
static const struct bpf_func_proto bpf_get_netns_cookie_sockopt_proto = { |
|
.func = bpf_get_netns_cookie_sockopt, |
|
.gpl_only = false, |
|
.ret_type = RET_INTEGER, |
|
.arg1_type = ARG_PTR_TO_CTX_OR_NULL, |
|
}; |
|
#endif |
|
|
|
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_get_netns_cookie: |
|
return &bpf_get_netns_cookie_sockopt_proto; |
|
case BPF_FUNC_sk_storage_get: |
|
return &bpf_sk_storage_get_proto; |
|
case BPF_FUNC_sk_storage_delete: |
|
return &bpf_sk_storage_delete_proto; |
|
case BPF_FUNC_setsockopt: |
|
if (prog->expected_attach_type == BPF_CGROUP_SETSOCKOPT) |
|
return &bpf_sk_setsockopt_proto; |
|
return NULL; |
|
case BPF_FUNC_getsockopt: |
|
if (prog->expected_attach_type == BPF_CGROUP_SETSOCKOPT) |
|
return &bpf_sk_getsockopt_proto; |
|
return NULL; |
|
#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 = { |
|
};
|
|
|