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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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SPDX-License-Identifier: GPL-2.0-only/* * Functions to manage eBPF programs attached to cgroups * * Copyright (c) 2016 Daniel Mack */
#include <linux/kernel.h>#include <linux/atomic.h>#include <linux/cgroup.h>#include <linux/filter.h>#include <linux/slab.h>#include <linux/sysctl.h>#include <linux/string.h>#include <linux/bpf.h>#include <linux/bpf-cgroup.h>#include <linux/bpf_lsm.h>#include <linux/bpf_verifier.h>#include <net/sock.h>#include <net/bpf_sk_storage.h>
#include "../cgroup/cgroup-internal.h"
DEFINE_STATIC_KEY_ARRAY_FALSE(cgroup_bpf_enabled_key, MAX_CGROUP_BPF_ATTACH_TYPE);EXPORT_SYMBOL(cgroup_bpf_enabled_key);
/* * cgroup bpf destruction makes heavy use of work items and there can be a lot * of concurrent destructions. Use a separate workqueue so that cgroup bpf * destruction work items don't end up filling up max_active of system_percpu_wq * which may lead to deadlock. */static struct workqueue_struct *cgroup_bpf_destroy_wq;
static int __init cgroup_bpf_wq_init(void){ cgroup_bpf_destroy_wq = alloc_workqueue("cgroup_bpf_destroy", WQ_PERCPU, 1); if (!cgroup_bpf_destroy_wq) panic("Failed to alloc workqueue for cgroup bpf destroy.\n"); return 0;}core_initcall(cgroup_bpf_wq_init);
static int cgroup_bpf_lifetime_notify(struct notifier_block *nb, unsigned long action, void *data);
static struct notifier_block cgroup_bpf_lifetime_nb = { .notifier_call = cgroup_bpf_lifetime_notify,};
void __init cgroup_bpf_lifetime_notifier_init(void){ BUG_ON(blocking_notifier_chain_register(&cgroup_lifetime_notifier, &cgroup_bpf_lifetime_nb));}
#ifdef CONFIG_BPF_LSMstruct cgroup_lsm_atype { u32 attach_btf_id; int refcnt; bool returns_errno;};
static struct cgroup_lsm_atype cgroup_lsm_atype[CGROUP_LSM_NUM];
static bool cgroup_bpf_hook_returns_errno(enum cgroup_bpf_attach_type atype){ if (atype >= CGROUP_LSM_START && atype <= CGROUP_LSM_END) return READ_ONCE(cgroup_lsm_atype[atype - CGROUP_LSM_START].returns_errno); return true;}#elsestatic bool cgroup_bpf_hook_returns_errno(enum cgroup_bpf_attach_type atype){ return true;}#endif
/* __always_inline is necessary to prevent indirect call through run_prog * function pointer. */static __always_inline intbpf_prog_run_array_cg(const struct cgroup_bpf *cgrp, enum cgroup_bpf_attach_type atype, const void *ctx, bpf_prog_run_fn run_prog, int retval, u32 *ret_flags){ const struct bpf_prog_array_item *item; const struct bpf_prog *prog; const struct bpf_prog_array *array; struct bpf_run_ctx *old_run_ctx; struct bpf_cg_run_ctx run_ctx; u32 func_ret;
run_ctx.retval = retval; rcu_read_lock_dont_migrate(); array = rcu_dereference(cgrp->effective[atype]); item = &array->items[0]; old_run_ctx = bpf_set_run_ctx(&run_ctx.run_ctx); while ((prog = READ_ONCE(item->prog))) { run_ctx.prog_item = item; func_ret = run_prog(prog, ctx); if (ret_flags) { *(ret_flags) |= (func_ret >> 1); func_ret &= 1; } if (!func_ret && cgroup_bpf_hook_returns_errno(atype) && !IS_ERR_VALUE((long)run_ctx.retval)) run_ctx.retval = -EPERM; item++; } bpf_reset_run_ctx(old_run_ctx); rcu_read_unlock_migrate(); return run_ctx.retval;}
unsigned int __cgroup_bpf_run_lsm_sock(const void *ctx, const struct bpf_insn *insn){ const struct bpf_prog *shim_prog; struct sock *sk; struct cgroup *cgrp; int ret = 0; u64 *args;
args = (u64 *)ctx; sk = (void *)(unsigned long)args[0]; /*shim_prog = container_of(insn, struct bpf_prog, insnsi);*/ shim_prog = (const struct bpf_prog *)((void *)insn - offsetof(struct bpf_prog, insnsi));
cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data); if (likely(cgrp)) ret = bpf_prog_run_array_cg(&cgrp->bpf, shim_prog->aux->cgroup_atype, ctx, bpf_prog_run, 0, NULL); return ret;}
unsigned int __cgroup_bpf_run_lsm_socket(const void *ctx, const struct bpf_insn *insn){ const struct bpf_prog *shim_prog; struct socket *sock; struct cgroup *cgrp; int ret = 0; u64 *args;
args = (u64 *)ctx; sock = (void *)(unsigned long)args[0]; /*shim_prog = container_of(insn, struct bpf_prog, insnsi);*/ shim_prog = (const struct bpf_prog *)((void *)insn - offsetof(struct bpf_prog, insnsi));
cgrp = sock_cgroup_ptr(&sock->sk->sk_cgrp_data); if (likely(cgrp)) ret = bpf_prog_run_array_cg(&cgrp->bpf, shim_prog->aux->cgroup_atype, ctx, bpf_prog_run, 0, NULL); return ret;}
unsigned int __cgroup_bpf_run_lsm_current(const void *ctx, const struct bpf_insn *insn){ const struct bpf_prog *shim_prog; struct cgroup *cgrp; int ret = 0;
/*shim_prog = container_of(insn, struct bpf_prog, insnsi);*/ shim_prog = (const struct bpf_prog *)((void *)insn - offsetof(struct bpf_prog, insnsi));
/* We rely on trampoline's __bpf_prog_enter_lsm_cgroup to grab RCU read lock. */ cgrp = task_dfl_cgroup(current); if (likely(cgrp)) ret = bpf_prog_run_array_cg(&cgrp->bpf, shim_prog->aux->cgroup_atype, ctx, bpf_prog_run, 0, NULL); return ret;}
#ifdef CONFIG_BPF_LSMstatic enum cgroup_bpf_attach_typebpf_cgroup_atype_find(enum bpf_attach_type attach_type, u32 attach_btf_id){ int i;
lockdep_assert_held(&cgroup_mutex);
if (attach_type != BPF_LSM_CGROUP) return to_cgroup_bpf_attach_type(attach_type);
for (i = 0; i < ARRAY_SIZE(cgroup_lsm_atype); i++) if (cgroup_lsm_atype[i].attach_btf_id == attach_btf_id) return CGROUP_LSM_START + i;
for (i = 0; i < ARRAY_SIZE(cgroup_lsm_atype); i++) if (cgroup_lsm_atype[i].attach_btf_id == 0) return CGROUP_LSM_START + i;
return -E2BIG;
}
void bpf_cgroup_atype_get(u32 attach_btf_id, int cgroup_atype){ int i = cgroup_atype - CGROUP_LSM_START;
lockdep_assert_held(&cgroup_mutex);
if (!cgroup_lsm_atype[i].attach_btf_id) { cgroup_lsm_atype[i].attach_btf_id = attach_btf_id; WRITE_ONCE(cgroup_lsm_atype[i].returns_errno, bpf_lsm_hook_returns_errno(attach_btf_id)); } else { WARN_ON_ONCE(cgroup_lsm_atype[i].attach_btf_id != attach_btf_id); } cgroup_lsm_atype[i].refcnt++;}
void bpf_cgroup_atype_put(int cgroup_atype){ int i = cgroup_atype - CGROUP_LSM_START;
cgroup_lock(); if (--cgroup_lsm_atype[i].refcnt <= 0) { WRITE_ONCE(cgroup_lsm_atype[i].returns_errno, true); cgroup_lsm_atype[i].attach_btf_id = 0; } WARN_ON_ONCE(cgroup_lsm_atype[i].refcnt < 0); cgroup_unlock();}#elsestatic enum cgroup_bpf_attach_typebpf_cgroup_atype_find(enum bpf_attach_type attach_type, u32 attach_btf_id){ if (attach_type != BPF_LSM_CGROUP) return to_cgroup_bpf_attach_type(attach_type); return -EOPNOTSUPP;}#endif /* CONFIG_BPF_LSM */
static 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 atype;
cgroup_lock();
for (atype = 0; atype < ARRAY_SIZE(cgrp->bpf.progs); atype++) { struct hlist_head *progs = &cgrp->bpf.progs[atype]; struct bpf_prog_list *pl; struct hlist_node *pltmp;
hlist_for_each_entry_safe(pl, pltmp, progs, node) { hlist_del(&pl->node); if (pl->prog) { if (pl->prog->expected_attach_type == BPF_LSM_CGROUP) bpf_trampoline_unlink_cgroup_shim(pl->prog); bpf_prog_put(pl->prog); } if (pl->link) { if (pl->link->link.prog->expected_attach_type == BPF_LSM_CGROUP) bpf_trampoline_unlink_cgroup_shim(pl->link->link.prog); bpf_cgroup_link_auto_detach(pl->link); } kfree(pl); static_branch_dec(&cgroup_bpf_enabled_key[atype]); } old_array = rcu_dereference_protected( cgrp->bpf.effective[atype], 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); }
cgroup_unlock();
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(cgroup_bpf_destroy_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 hlist_head *head, int *preorder_cnt){ struct bpf_prog_list *pl; u32 cnt = 0;
hlist_for_each_entry(pl, head, node) { if (!prog_list_prog(pl)) continue; if (preorder_cnt && (pl->flags & BPF_F_PREORDER)) (*preorder_cnt)++; 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 cgroup_bpf_attach_type atype){ struct cgroup *p;
p = cgroup_parent(cgrp); if (!p) return true; do { u32 flags = p->bpf.flags[atype]; u32 cnt;
if (flags & BPF_F_ALLOW_MULTI) return true; cnt = prog_list_length(&p->bpf.progs[atype], NULL); 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 cgroup_bpf_attach_type atype, 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 i, j, cnt = 0, preorder_cnt = 0, fstart, bstart, init_bstart;
/* 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], &preorder_cnt); 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; fstart = preorder_cnt; bstart = preorder_cnt - 1; do { if (cnt > 0 && !(p->bpf.flags[atype] & BPF_F_ALLOW_MULTI)) continue;
init_bstart = bstart; hlist_for_each_entry(pl, &p->bpf.progs[atype], node) { if (!prog_list_prog(pl)) continue;
if (pl->flags & BPF_F_PREORDER) { item = &progs->items[bstart]; bstart--; } else { item = &progs->items[fstart]; fstart++; } item->prog = prog_list_prog(pl); bpf_cgroup_storages_assign(item->cgroup_storage, pl->storage); cnt++; }
/* reverse pre-ordering progs at this cgroup level */ for (i = bstart + 1, j = init_bstart; i < j; i++, j--) swap(progs->items[i], progs->items[j]);
} while ((p = cgroup_parent(p)));
*array = progs; return 0;}
static void activate_effective_progs(struct cgroup *cgrp, enum cgroup_bpf_attach_type atype, struct bpf_prog_array *old_array){ old_array = rcu_replace_pointer(cgrp->bpf.effective[atype], 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 */static int cgroup_bpf_inherit(struct cgroup *cgrp){/* has to use marco instead of const int, since compiler thinks * that array below is variable length */#define NR ARRAY_SIZE(cgrp->bpf.effective) struct bpf_prog_array *arrays[NR] = {}; struct cgroup *p; int ret, i;
ret = percpu_ref_init(&cgrp->bpf.refcnt, cgroup_bpf_release_fn, 0, GFP_KERNEL); if (ret) return ret;
for (p = cgroup_parent(cgrp); p; p = cgroup_parent(p)) cgroup_bpf_get(p);
for (i = 0; i < NR; i++) INIT_HLIST_HEAD(&cgrp->bpf.progs[i]);
INIT_LIST_HEAD(&cgrp->bpf.storages);
for (i = 0; i < NR; i++) if (compute_effective_progs(cgrp, i, &arrays[i])) goto cleanup;
for (i = 0; i < NR; i++) activate_effective_progs(cgrp, i, arrays[i]);
return 0;cleanup: for (i = 0; i < NR; i++) bpf_prog_array_free(arrays[i]);
for (p = cgroup_parent(cgrp); p; p = cgroup_parent(p)) cgroup_bpf_put(p);
percpu_ref_exit(&cgrp->bpf.refcnt);
return -ENOMEM;}
static int cgroup_bpf_lifetime_notify(struct notifier_block *nb, unsigned long action, void *data){ struct cgroup *cgrp = data; int ret = 0;
if (cgrp->root != &cgrp_dfl_root) return NOTIFY_OK;
switch (action) { case CGROUP_LIFETIME_ONLINE: ret = cgroup_bpf_inherit(cgrp); break; case CGROUP_LIFETIME_OFFLINE: cgroup_bpf_offline(cgrp); break; }
return notifier_from_errno(ret);}
static int update_effective_progs(struct cgroup *cgrp, enum cgroup_bpf_attach_type atype){ 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, 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 hlist_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 (hlist_empty(progs)) return NULL; return hlist_entry(progs->first, typeof(*pl), node); }
hlist_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) { hlist_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;}
static struct bpf_link *bpf_get_anchor_link(u32 flags, u32 id_or_fd){ struct bpf_link *link = ERR_PTR(-EINVAL);
if (flags & BPF_F_ID) link = bpf_link_by_id(id_or_fd); else if (id_or_fd) link = bpf_link_get_from_fd(id_or_fd); return link;}
static struct bpf_prog *bpf_get_anchor_prog(u32 flags, u32 id_or_fd){ struct bpf_prog *prog = ERR_PTR(-EINVAL);
if (flags & BPF_F_ID) prog = bpf_prog_by_id(id_or_fd); else if (id_or_fd) prog = bpf_prog_get(id_or_fd); return prog;}
static struct bpf_prog_list *get_prog_list(struct hlist_head *progs, struct bpf_prog *prog, struct bpf_cgroup_link *link, u32 flags, u32 id_or_fd){ bool is_link = flags & BPF_F_LINK, is_id = flags & BPF_F_ID; struct bpf_prog_list *pltmp, *pl = ERR_PTR(-EINVAL); bool preorder = flags & BPF_F_PREORDER; struct bpf_link *anchor_link = NULL; struct bpf_prog *anchor_prog = NULL; bool is_before, is_after;
is_before = flags & BPF_F_BEFORE; is_after = flags & BPF_F_AFTER; if (is_link || is_id || id_or_fd) { /* flags must have either BPF_F_BEFORE or BPF_F_AFTER */ if (is_before == is_after) return ERR_PTR(-EINVAL); if ((is_link && !link) || (!is_link && !prog)) return ERR_PTR(-EINVAL); } else if (!hlist_empty(progs)) { /* flags cannot have both BPF_F_BEFORE and BPF_F_AFTER */ if (is_before && is_after) return ERR_PTR(-EINVAL); }
if (is_link) { anchor_link = bpf_get_anchor_link(flags, id_or_fd); if (IS_ERR(anchor_link)) return ERR_CAST(anchor_link); } else if (is_id || id_or_fd) { anchor_prog = bpf_get_anchor_prog(flags, id_or_fd); if (IS_ERR(anchor_prog)) return ERR_CAST(anchor_prog); }
if (!anchor_prog && !anchor_link) { /* if there is no anchor_prog/anchor_link, then BPF_F_PREORDER * doesn't matter since either prepend or append to a combined * list of progs will end up with correct result. */ hlist_for_each_entry(pltmp, progs, node) { if (is_before) return pltmp; if (pltmp->node.next) continue; return pltmp; } return NULL; }
hlist_for_each_entry(pltmp, progs, node) { if ((anchor_prog && anchor_prog == pltmp->prog) || (anchor_link && anchor_link == &pltmp->link->link)) { if (!!(pltmp->flags & BPF_F_PREORDER) != preorder) goto out; pl = pltmp; goto out; } }
pl = ERR_PTR(-ENOENT);out: if (anchor_link) bpf_link_put(anchor_link); else bpf_prog_put(anchor_prog); return pl;}
static int insert_pl_to_hlist(struct bpf_prog_list *pl, struct hlist_head *progs, struct bpf_prog *prog, struct bpf_cgroup_link *link, u32 flags, u32 id_or_fd){ struct bpf_prog_list *pltmp;
pltmp = get_prog_list(progs, prog, link, flags, id_or_fd); if (IS_ERR(pltmp)) return PTR_ERR(pltmp);
if (!pltmp) hlist_add_head(&pl->node, progs); else if (flags & BPF_F_BEFORE) hlist_add_before(&pl->node, &pltmp->node); else hlist_add_behind(&pl->node, &pltmp->node);
return 0;}
/** * __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 * @id_or_fd: Relative prog id or fd * @revision: bpf_prog_list revision * * Exactly one of @prog or @link can be non-null. * Must be called with cgroup_mutex held. */static 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 id_or_fd, u64 revision){ 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] = {}; struct bpf_prog *new_prog = prog ? : link->link.prog; enum cgroup_bpf_attach_type atype; struct bpf_prog_list *pl; struct hlist_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 ((flags & BPF_F_REPLACE) && (flags & (BPF_F_BEFORE | BPF_F_AFTER))) /* only either replace or insertion with before/after */ 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 = bpf_cgroup_atype_find(type, new_prog->aux->attach_btf_id); if (atype < 0) return -EINVAL; if (revision && revision != cgrp->bpf.revisions[atype]) return -ESTALE;
progs = &cgrp->bpf.progs[atype];
if (!hierarchy_allows_attach(cgrp, atype)) return -EPERM;
if (!hlist_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, NULL) >= 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_obj(*pl); if (!pl) { bpf_cgroup_storages_free(new_storage); return -ENOMEM; }
err = insert_pl_to_hlist(pl, progs, prog, link, flags, id_or_fd); if (err) { kfree(pl); bpf_cgroup_storages_free(new_storage); return err; } }
pl->prog = prog; pl->link = link; pl->flags = flags; bpf_cgroup_storages_assign(pl->storage, storage); cgrp->bpf.flags[atype] = saved_flags;
if (type == BPF_LSM_CGROUP) { err = bpf_trampoline_link_cgroup_shim(new_prog, atype, type); if (err) goto cleanup; }
err = update_effective_progs(cgrp, atype); if (err) goto cleanup_trampoline;
cgrp->bpf.revisions[atype] += 1; if (old_prog) { if (type == BPF_LSM_CGROUP) bpf_trampoline_unlink_cgroup_shim(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_trampoline: if (type == BPF_LSM_CGROUP) bpf_trampoline_unlink_cgroup_shim(new_prog);
cleanup: if (old_prog) { pl->prog = old_prog; pl->link = NULL; } bpf_cgroup_storages_free(new_storage); if (!old_prog) { hlist_del(&pl->node); kfree(pl); } return err;}
static 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 id_or_fd, u64 revision){ int ret;
cgroup_lock(); ret = __cgroup_bpf_attach(cgrp, prog, replace_prog, link, type, flags, id_or_fd, revision); cgroup_unlock(); return ret;}
static int effective_prog_pos(struct cgroup *cgrp, enum cgroup_bpf_attach_type atype, struct bpf_prog_list *target_pl){ int cnt = 0, preorder_cnt = 0, fstart, bstart, init_bstart, pos = -1; struct bpf_prog_list *pl; struct cgroup *p = cgrp;
/* count effective programs to find where the preorder region ends */ do { if (cnt == 0 || (p->bpf.flags[atype] & BPF_F_ALLOW_MULTI)) cnt += prog_list_length(&p->bpf.progs[atype], &preorder_cnt); p = cgroup_parent(p); } while (p);
/* replay compute_effective_progs() placement and record target's slot */ cnt = 0; p = cgrp; fstart = preorder_cnt; bstart = preorder_cnt - 1; do { if (cnt > 0 && !(p->bpf.flags[atype] & BPF_F_ALLOW_MULTI)) continue;
init_bstart = bstart; hlist_for_each_entry(pl, &p->bpf.progs[atype], node) { if (!prog_list_prog(pl)) continue;
if (pl->flags & BPF_F_PREORDER) { if (pl == target_pl) pos = bstart; bstart--; } else { if (pl == target_pl) pos = fstart; fstart++; } cnt++; }
/* reverse pre-ordering progs at this cgroup level */ if (pos >= bstart + 1 && pos <= init_bstart) pos = bstart + 1 + init_bstart - pos; } while ((p = cgroup_parent(p)));
return pos;}
/* 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_prog_list *pl){ struct bpf_prog_array_item *item; struct cgroup_subsys_state *css; struct bpf_prog_array *progs; 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;
pos = effective_prog_pos(desc, atype, pl); if (WARN_ON_ONCE(pos < 0)) continue;
progs = rcu_dereference_protected( desc->bpf.effective[atype], lockdep_is_held(&cgroup_mutex)); item = &progs->items[pos]; WRITE_ONCE(item->prog, pl->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 * @new_prog: &struct bpf_prog for the target BPF program with its refcnt * incremented * * 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 hlist_head *progs; bool found = false;
atype = bpf_cgroup_atype_find(link->link.attach_type, new_prog->aux->attach_btf_id); if (atype < 0) return -EINVAL;
progs = &cgrp->bpf.progs[atype];
if (link->link.prog->type != new_prog->type) return -EINVAL;
hlist_for_each_entry(pl, progs, node) { if (pl->link == link) { found = true; break; } } if (!found) return -ENOENT;
cgrp->bpf.revisions[atype] += 1; old_prog = xchg(&link->link.prog, new_prog); replace_effective_prog(cgrp, atype, pl); 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);
cgroup_lock(); /* 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: cgroup_unlock(); return ret;}
static struct bpf_prog_list *find_detach_entry(struct hlist_head *progs, struct bpf_prog *prog, struct bpf_cgroup_link *link, bool allow_multi){ struct bpf_prog_list *pl;
if (!allow_multi) { if (hlist_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 hlist_entry(progs->first, 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 */ hlist_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 * @pl: The prog_list entry being detached * @atype: Type of detach operation */static void purge_effective_progs(struct cgroup *cgrp, struct bpf_prog_list *pl, enum cgroup_bpf_attach_type atype){ struct cgroup_subsys_state *css; struct bpf_prog_array *progs; 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;
pos = effective_prog_pos(desc, atype, pl); /* no link or prog match, skip the cgroup of this layer */ if (pos < 0) continue;
progs = rcu_dereference_protected( desc->bpf.effective[atype], 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 * @link: A link to detach or NULL * @type: Type of detach operation * @revision: bpf_prog_list revision * * At most one of @prog or @link can be non-NULL. * Must be called with cgroup_mutex held. */static int __cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog, struct bpf_cgroup_link *link, enum bpf_attach_type type, u64 revision){ enum cgroup_bpf_attach_type atype; struct bpf_prog *old_prog; struct bpf_prog_list *pl; struct hlist_head *progs; u32 attach_btf_id = 0; u32 flags;
if (prog) attach_btf_id = prog->aux->attach_btf_id; if (link) attach_btf_id = link->link.prog->aux->attach_btf_id;
atype = bpf_cgroup_atype_find(type, attach_btf_id); if (atype < 0) return -EINVAL;
if (revision && revision != cgrp->bpf.revisions[atype]) return -ESTALE;
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;
if (update_effective_progs(cgrp, atype)) { /* if update effective array failed replace the prog with a dummy prog*/ pl->prog = old_prog; pl->link = link; purge_effective_progs(cgrp, pl, atype); }
/* now can actually delete it from this cgroup list */ hlist_del(&pl->node); cgrp->bpf.revisions[atype] += 1;
kfree(pl); if (hlist_empty(progs)) /* last program was detached, reset flags to zero */ cgrp->bpf.flags[atype] = 0; if (old_prog) { if (type == BPF_LSM_CGROUP) bpf_trampoline_unlink_cgroup_shim(old_prog); bpf_prog_put(old_prog); } static_branch_dec(&cgroup_bpf_enabled_key[atype]); return 0;}
static int cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog, enum bpf_attach_type type, u64 revision){ int ret;
cgroup_lock(); ret = __cgroup_bpf_detach(cgrp, prog, NULL, type, revision); cgroup_unlock(); return ret;}
/* Must be called with cgroup_mutex held to avoid races. */static int __cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr, union bpf_attr __user *uattr, u32 uattr_size){ __u32 __user *prog_attach_flags = u64_to_user_ptr(attr->query.prog_attach_flags); bool effective_query = attr->query.query_flags & BPF_F_QUERY_EFFECTIVE; __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 from_atype, to_atype; enum cgroup_bpf_attach_type atype; struct bpf_prog_array *effective; int cnt, ret = 0, i; int total_cnt = 0; u64 revision = 0; u32 flags;
if (effective_query && prog_attach_flags) return -EINVAL;
if (type == BPF_LSM_CGROUP) { if (!effective_query && attr->query.prog_cnt && prog_ids && !prog_attach_flags) return -EINVAL;
from_atype = CGROUP_LSM_START; to_atype = CGROUP_LSM_END; flags = 0; } else { from_atype = to_cgroup_bpf_attach_type(type); if (from_atype < 0) return -EINVAL; to_atype = from_atype; flags = cgrp->bpf.flags[from_atype]; }
for (atype = from_atype; atype <= to_atype; atype++) { if (effective_query) { effective = rcu_dereference_protected(cgrp->bpf.effective[atype], lockdep_is_held(&cgroup_mutex)); total_cnt += bpf_prog_array_length(effective); } else { total_cnt += prog_list_length(&cgrp->bpf.progs[atype], NULL); } }
/* always output uattr->query.attach_flags as 0 during effective query */ flags = effective_query ? 0 : flags; if (copy_to_user(&uattr->query.attach_flags, &flags, sizeof(flags))) return -EFAULT; if (copy_to_user(&uattr->query.prog_cnt, &total_cnt, sizeof(total_cnt))) return -EFAULT; if (!effective_query && from_atype == to_atype) revision = cgrp->bpf.revisions[from_atype]; if (uattr_size >= offsetofend(union bpf_attr, query.revision) && copy_to_user(&uattr->query.revision, &revision, sizeof(revision))) return -EFAULT; if (attr->query.prog_cnt == 0 || !prog_ids || !total_cnt) /* return early if user requested only program count + flags */ return 0;
if (attr->query.prog_cnt < total_cnt) { total_cnt = attr->query.prog_cnt; ret = -ENOSPC; }
for (atype = from_atype; atype <= to_atype && total_cnt; atype++) { if (effective_query) { effective = rcu_dereference_protected(cgrp->bpf.effective[atype], lockdep_is_held(&cgroup_mutex)); cnt = min_t(int, bpf_prog_array_length(effective), total_cnt); ret = bpf_prog_array_copy_to_user(effective, prog_ids, cnt); } else { struct hlist_head *progs; struct bpf_prog_list *pl; struct bpf_prog *prog; u32 id;
progs = &cgrp->bpf.progs[atype]; cnt = min_t(int, prog_list_length(progs, NULL), total_cnt); i = 0; hlist_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; }
if (prog_attach_flags) { flags = cgrp->bpf.flags[atype];
for (i = 0; i < cnt; i++) if (copy_to_user(prog_attach_flags + i, &flags, sizeof(flags))) return -EFAULT; prog_attach_flags += cnt; } }
prog_ids += cnt; total_cnt -= cnt; } return ret;}
static int cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr, union bpf_attr __user *uattr, u32 uattr_size){ int ret;
cgroup_lock(); ret = __cgroup_bpf_query(cgrp, attr, uattr, uattr_size); cgroup_unlock(); 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, attr->relative_fd, attr->expected_revision);
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, attr->expected_revision); 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;
cgroup_lock();
/* re-check cgroup under lock again */ if (!cg_link->cgroup) { cgroup_unlock(); return; }
WARN_ON(__cgroup_bpf_detach(cg_link->cgroup, NULL, cg_link, link->attach_type, 0)); if (link->attach_type == BPF_LSM_CGROUP) bpf_trampoline_unlink_cgroup_shim(cg_link->link.prog);
cg = cg_link->cgroup; cg_link->cgroup = NULL;
cgroup_unlock();
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;
cgroup_lock(); if (cg_link->cgroup) cg_id = cgroup_id(cg_link->cgroup); cgroup_unlock();
seq_printf(seq, "cgroup_id:\t%llu\n" "attach_type:\t%d\n", cg_id, link->attach_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;
cgroup_lock(); if (cg_link->cgroup) cg_id = cgroup_id(cg_link->cgroup); cgroup_unlock();
info->cgroup.cgroup_id = cg_id; info->cgroup.attach_type = link->attach_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,};
#define BPF_F_LINK_ATTACH_MASK \ (BPF_F_ID | \ BPF_F_BEFORE | \ BPF_F_AFTER | \ BPF_F_PREORDER | \ BPF_F_LINK)
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 & (~BPF_F_LINK_ATTACH_MASK)) return -EINVAL;
cgrp = cgroup_get_from_fd(attr->link_create.target_fd); if (IS_ERR(cgrp)) return PTR_ERR(cgrp);
link = kzalloc_obj(*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, attr->link_create.attach_type); link->cgroup = cgrp;
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->link.attach_type, BPF_F_ALLOW_MULTI | attr->link_create.flags, attr->link_create.cgroup.relative_fd, attr->link_create.cgroup.expected_revision); 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, u32 uattr_size){ 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, uattr_size);
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 * @atype: The type of program to be executed * * 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 * -err - 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_network_offset(skb); struct sock *save_sk; void *saved_data_end; struct cgroup *cgrp; int ret;
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) { u32 flags = 0; bool cn;
ret = bpf_prog_run_array_cg(&cgrp->bpf, atype, skb, __bpf_prog_run_save_cb, 0, &flags);
/* Return values of CGROUP EGRESS BPF programs are: * 0: drop packet * 1: keep packet * 2: drop packet and cn * 3: keep packet and cn * * The returned value is then converted to one of the NET_XMIT * or an error code that is then interpreted as drop packet * (and no cn): * 0: NET_XMIT_SUCCESS skb should be transmitted * 1: NET_XMIT_DROP skb should be dropped and cn * 2: NET_XMIT_CN skb should be transmitted and cn * 3: -err skb should be dropped */
cn = flags & BPF_RET_SET_CN; if (ret && !IS_ERR_VALUE((long)ret)) ret = -EFAULT; if (!ret) ret = (cn ? NET_XMIT_CN : NET_XMIT_SUCCESS); else ret = (cn ? NET_XMIT_DROP : ret); } else { ret = bpf_prog_run_array_cg(&cgrp->bpf, atype, skb, __bpf_prog_run_save_cb, 0, NULL); if (ret && !IS_ERR_VALUE((long)ret)) ret = -EFAULT; } 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 * @atype: The type of program to be executed * * 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);
return bpf_prog_run_array_cg(&cgrp->bpf, atype, sk, bpf_prog_run, 0, NULL);}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 * @uaddrlen: Pointer to the size of the sockaddr struct provided by user. It is * read-only for AF_INET[6] uaddr but can be modified for AF_UNIX * uaddr. * @atype: The type of program to be executed * @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, INET6 or UNIX. * * 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_unsized *uaddr, int *uaddrlen, 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 storage; struct cgroup *cgrp; int ret;
if (!sk_is_inet(sk) && !sk_is_unix(sk)) return 0;
if (!ctx.uaddr) { memset(&storage, 0, sizeof(storage)); ctx.uaddr = (struct sockaddr_unsized *)&storage; ctx.uaddrlen = 0; } else { ctx.uaddrlen = *uaddrlen; }
cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data); ret = bpf_prog_run_array_cg(&cgrp->bpf, atype, &ctx, bpf_prog_run, 0, flags);
if (!ret && uaddr) *uaddrlen = ctx.uaddrlen;
return ret;}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. * @atype: The type of program to be executed * * 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);
return bpf_prog_run_array_cg(&cgrp->bpf, atype, sock_ops, bpf_prog_run, 0, NULL);}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 ret;
rcu_read_lock(); cgrp = task_dfl_cgroup(current); ret = bpf_prog_run_array_cg(&cgrp->bpf, atype, &ctx, bpf_prog_run, 0, NULL); rcu_read_unlock();
return ret;}
BPF_CALL_2(bpf_get_local_storage, struct bpf_map *, map, u64, flags){ /* flags argument is not used now, * but provides an ability to extend the API. * verifier checks that its value is correct. */ enum bpf_cgroup_storage_type stype = cgroup_storage_type(map); struct bpf_cgroup_storage *storage; struct bpf_cg_run_ctx *ctx; void *ptr;
/* get current cgroup storage from BPF run context */ ctx = container_of(current->bpf_ctx, struct bpf_cg_run_ctx, run_ctx); storage = ctx->prog_item->cgroup_storage[stype];
if (stype == BPF_CGROUP_STORAGE_SHARED) ptr = &READ_ONCE(storage->buf)->data[0]; else ptr = this_cpu_ptr(storage->percpu_buf);
return (unsigned long)ptr;}
const struct bpf_func_proto bpf_get_local_storage_proto = { .func = bpf_get_local_storage, .gpl_only = false, .ret_type = RET_PTR_TO_MAP_VALUE, .arg1_type = ARG_CONST_MAP_PTR, .arg2_type = ARG_ANYTHING,};
BPF_CALL_0(bpf_get_retval){ struct bpf_cg_run_ctx *ctx = container_of(current->bpf_ctx, struct bpf_cg_run_ctx, run_ctx);
return ctx->retval;}
const struct bpf_func_proto bpf_get_retval_proto = { .func = bpf_get_retval, .gpl_only = false, .ret_type = RET_INTEGER,};
BPF_CALL_1(bpf_set_retval, int, retval){ struct bpf_cg_run_ctx *ctx = container_of(current->bpf_ctx, struct bpf_cg_run_ctx, run_ctx);
ctx->retval = retval; return 0;}
const struct bpf_func_proto bpf_set_retval_proto = { .func = bpf_set_retval, .gpl_only = false, .ret_type = RET_INTEGER, .arg1_type = ARG_ANYTHING,};
static const struct bpf_func_proto *cgroup_dev_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog){ const struct bpf_func_proto *func_proto;
func_proto = cgroup_common_func_proto(func_id, prog); if (func_proto) return func_proto;
switch (func_id) { case BPF_FUNC_perf_event_output: return &bpf_event_output_data_proto; default: return bpf_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 * @atype: 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, const 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, atype, &ctx, bpf_prog_run, 0, NULL); rcu_read_unlock();
kfree(ctx.cur_val);
if (!ret && ctx.new_updated) { kvfree(*buf); *buf = ctx.new_val; *pcount = ctx.new_len; } else { kfree(ctx.new_val); }
return ret;}
#ifdef CONFIG_NETstatic 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, sockptr_t 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;
/* 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_sockptr(ctx.optval, optval, min(*optlen, max_optlen))) { ret = -EFAULT; goto out; }
lock_sock(sk); ret = bpf_prog_run_array_cg(&cgrp->bpf, CGROUP_SETSOCKOPT, &ctx, bpf_prog_run, 0, NULL); release_sock(sk);
if (ret) 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 */ if (*optlen > PAGE_SIZE && ctx.optlen >= 0) { pr_info_once("bpf setsockopt: ignoring program buffer with optlen=%d (max_optlen=%d)\n", ctx.optlen, max_optlen); ret = 0; goto out; } 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, sockptr_t optval, sockptr_t 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, .current_task = current, }; int orig_optlen; int ret;
orig_optlen = max_optlen; 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 (copy_from_sockptr(&ctx.optlen, optlen, sizeof(ctx.optlen))) { ret = -EFAULT; goto out; }
if (ctx.optlen < 0) { ret = -EFAULT; goto out; } orig_optlen = ctx.optlen;
if (copy_from_sockptr(ctx.optval, optval, min(ctx.optlen, max_optlen))) { ret = -EFAULT; goto out; } }
lock_sock(sk); ret = bpf_prog_run_array_cg(&cgrp->bpf, CGROUP_GETSOCKOPT, &ctx, bpf_prog_run, retval, NULL); release_sock(sk);
if (ret < 0) goto out;
if (!sockptr_is_null(optval) && (ctx.optlen > max_optlen || ctx.optlen < 0)) { if (orig_optlen > PAGE_SIZE && ctx.optlen >= 0) { pr_info_once("bpf getsockopt: ignoring program buffer with optlen=%d (max_optlen=%d)\n", ctx.optlen, max_optlen); ret = retval; goto out; } ret = -EFAULT; goto out; }
if (ctx.optlen != 0) { if (!sockptr_is_null(optval) && copy_to_sockptr(optval, ctx.optval, ctx.optlen)) { ret = -EFAULT; goto out; } if (copy_to_sockptr(optlen, &ctx.optlen, sizeof(ctx.optlen))) { ret = -EFAULT; goto out; } }
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, .optlen = *optlen, .optval = optval, .optval_end = optval + *optlen, .current_task = current, }; 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, CGROUP_GETSOCKOPT, &ctx, bpf_prog_run, retval, NULL); if (ret < 0) return ret;
if (ctx.optlen > *optlen) return -EFAULT;
/* BPF programs can shrink the buffer, export the modifications. */ if (ctx.optlen != 0) *optlen = ctx.optlen;
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 | MEM_WRITE, .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); ((char *)ctx->new_val)[buf_len] = '\0'; 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 | MEM_RDONLY, .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){ const struct bpf_func_proto *func_proto;
func_proto = cgroup_common_func_proto(func_id, prog); if (func_proto) return func_proto;
switch (func_id) { 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; case BPF_FUNC_ktime_get_coarse_ns: return &bpf_ktime_get_coarse_ns_proto; case BPF_FUNC_perf_event_output: return &bpf_event_output_data_proto; default: return bpf_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_RAW_INSN( BPF_CLASS(si->code) | BPF_MEM | BPF_SIZEOF(u32), treg, si->src_reg, bpf_ctx_narrow_access_offset( 0, sizeof(u32), sizeof(loff_t)), si->imm); *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_NETBPF_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){ const struct bpf_func_proto *func_proto;
func_proto = cgroup_common_func_proto(func_id, prog); if (func_proto) return func_proto;
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 case BPF_FUNC_perf_event_output: return &bpf_event_output_data_proto; default: return bpf_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 bpf_ctx_range_ptr(struct bpf_sockopt, sk): if (size != sizeof(__u64)) return false; info->reg_type = PTR_TO_SOCKET; break; case bpf_ctx_range_ptr(struct bpf_sockopt, optval): if (size != sizeof(__u64)) return false; info->reg_type = PTR_TO_PACKET; break; case bpf_ctx_range_ptr(struct bpf_sockopt, optval_end): if (size != sizeof(__u64)) return false; info->reg_type = PTR_TO_PACKET_END; break; case bpf_ctx_range(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_READ_FIELD(F) \ BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_sockopt_kern, F), \ si->dst_reg, si->src_reg, \ offsetof(struct bpf_sockopt_kern, F))
#define CG_SOCKOPT_WRITE_FIELD(F) \ BPF_RAW_INSN((BPF_FIELD_SIZEOF(struct bpf_sockopt_kern, F) | \ BPF_MEM | BPF_CLASS(si->code)), \ si->dst_reg, si->src_reg, \ offsetof(struct bpf_sockopt_kern, F), \ si->imm)
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_READ_FIELD(sk); break; case offsetof(struct bpf_sockopt, level): if (type == BPF_WRITE) *insn++ = CG_SOCKOPT_WRITE_FIELD(level); else *insn++ = CG_SOCKOPT_READ_FIELD(level); break; case offsetof(struct bpf_sockopt, optname): if (type == BPF_WRITE) *insn++ = CG_SOCKOPT_WRITE_FIELD(optname); else *insn++ = CG_SOCKOPT_READ_FIELD(optname); break; case offsetof(struct bpf_sockopt, optlen): if (type == BPF_WRITE) *insn++ = CG_SOCKOPT_WRITE_FIELD(optlen); else *insn++ = CG_SOCKOPT_READ_FIELD(optlen); break; case offsetof(struct bpf_sockopt, retval): BUILD_BUG_ON(offsetof(struct bpf_cg_run_ctx, run_ctx) != 0);
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_sockopt_kern, tmp_reg)); *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_sockopt_kern, current_task), treg, si->dst_reg, offsetof(struct bpf_sockopt_kern, current_task)); *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct task_struct, bpf_ctx), treg, treg, offsetof(struct task_struct, bpf_ctx)); *insn++ = BPF_RAW_INSN(BPF_CLASS(si->code) | BPF_MEM | BPF_FIELD_SIZEOF(struct bpf_cg_run_ctx, retval), treg, si->src_reg, offsetof(struct bpf_cg_run_ctx, retval), si->imm); *insn++ = BPF_LDX_MEM(BPF_DW, treg, si->dst_reg, offsetof(struct bpf_sockopt_kern, tmp_reg)); } else { *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_sockopt_kern, current_task), si->dst_reg, si->src_reg, offsetof(struct bpf_sockopt_kern, current_task)); *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct task_struct, bpf_ctx), si->dst_reg, si->dst_reg, offsetof(struct task_struct, bpf_ctx)); *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_cg_run_ctx, retval), si->dst_reg, si->dst_reg, offsetof(struct bpf_cg_run_ctx, retval)); } break; case offsetof(struct bpf_sockopt, optval): *insn++ = CG_SOCKOPT_READ_FIELD(optval); break; case offsetof(struct bpf_sockopt, optval_end): *insn++ = CG_SOCKOPT_READ_FIELD(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 = {};
/* Common helpers for cgroup hooks. */const struct bpf_func_proto *cgroup_common_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog){ switch (func_id) { case BPF_FUNC_get_local_storage: return &bpf_get_local_storage_proto; case BPF_FUNC_get_retval: switch (prog->expected_attach_type) { case BPF_CGROUP_INET_INGRESS: case BPF_CGROUP_INET_EGRESS: case BPF_CGROUP_SOCK_OPS: case BPF_CGROUP_UDP4_RECVMSG: case BPF_CGROUP_UDP6_RECVMSG: case BPF_CGROUP_UNIX_RECVMSG: case BPF_CGROUP_INET4_GETPEERNAME: case BPF_CGROUP_INET6_GETPEERNAME: case BPF_CGROUP_UNIX_GETPEERNAME: case BPF_CGROUP_INET4_GETSOCKNAME: case BPF_CGROUP_INET6_GETSOCKNAME: case BPF_CGROUP_UNIX_GETSOCKNAME: return NULL; default: return &bpf_get_retval_proto; } case BPF_FUNC_set_retval: switch (prog->expected_attach_type) { case BPF_CGROUP_INET_INGRESS: case BPF_CGROUP_INET_EGRESS: case BPF_CGROUP_SOCK_OPS: case BPF_CGROUP_UDP4_RECVMSG: case BPF_CGROUP_UDP6_RECVMSG: case BPF_CGROUP_UNIX_RECVMSG: case BPF_CGROUP_INET4_GETPEERNAME: case BPF_CGROUP_INET6_GETPEERNAME: case BPF_CGROUP_UNIX_GETPEERNAME: case BPF_CGROUP_INET4_GETSOCKNAME: case BPF_CGROUP_INET6_GETSOCKNAME: case BPF_CGROUP_UNIX_GETSOCKNAME: return NULL; default: return &bpf_set_retval_proto; } default: return NULL; }}