// 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>
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#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;
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|
for (p = cgroup_parent(cgrp); p; p = cgroup_parent(p))
|
cgroup_bpf_get(p);
|
|
for (i = 0; i < NR; i++)
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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]);
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|
return 0;
|
cleanup:
|
for (i = 0; i < NR; i++)
|
bpf_prog_array_free(arrays[i]);
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|
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);
|
}
|
|
/**
|
* purge_effective_progs() - After compute_effective_progs fails to alloc new
|
* cgrp->bpf.inactive table we can recover by
|
* recomputing the array in place.
|
*
|
* @cgrp: The cgroup which descendants to travers
|
* @prog: A program to detach or NULL
|
* @link: A link to detach or NULL
|
* @type: Type of detach operation
|
*/
|
static void purge_effective_progs(struct cgroup *cgrp, struct bpf_prog *prog,
|
struct bpf_cgroup_link *link,
|
enum bpf_attach_type type)
|
{
|
struct cgroup_subsys_state *css;
|
struct bpf_prog_array *progs;
|
struct bpf_prog_list *pl;
|
struct list_head *head;
|
struct cgroup *cg;
|
int pos;
|
|
/* recompute effective prog array in place */
|
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 or prog 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->prog == prog && pl->link == link)
|
goto found;
|
pos++;
|
}
|
}
|
|
/* no link or prog match, skip the cgroup of this layer */
|
continue;
|
found:
|
progs = rcu_dereference_protected(
|
desc->bpf.effective[type],
|
lockdep_is_held(&cgroup_mutex));
|
|
/* Remove the program from the array */
|
WARN_ONCE(bpf_prog_array_delete_safe_at(progs, pos),
|
"Failed to purge a prog from array at index %d", pos);
|
}
|
}
|
|
/**
|
* __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;
|
|
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;
|
|
if (update_effective_progs(cgrp, type)) {
|
/* if update effective array failed replace the prog with a dummy prog*/
|
pl->prog = old_prog;
|
pl->link = link;
|
purge_effective_progs(cgrp, old_prog, link, type);
|
}
|
|
/* 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;
|
}
|
|
/* 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 = {
|
};
|
