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// SPDX-License-Identifier: GPL-2.0 /* Copyright (c) 2017 - 2018 Covalent IO, Inc. http://covalent.io */ #include <linux/bpf.h> #include <linux/filter.h> #include <linux/errno.h> #include <linux/file.h> #include <linux/net.h> #include <linux/workqueue.h> #include <linux/skmsg.h> #include <linux/list.h> #include <linux/jhash.h> #include <linux/sock_diag.h> #include <net/udp.h> struct bpf_stab { struct bpf_map map; struct sock **sks; struct sk_psock_progs progs; raw_spinlock_t lock; }; #define SOCK_CREATE_FLAG_MASK \ (BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY) static struct bpf_map *sock_map_alloc(union bpf_attr *attr) { struct bpf_stab *stab; u64 cost; int err; if (!capable(CAP_NET_ADMIN)) return ERR_PTR(-EPERM); if (attr->max_entries == 0 || attr->key_size != 4 || (attr->value_size != sizeof(u32) && attr->value_size != sizeof(u64)) || attr->map_flags & ~SOCK_CREATE_FLAG_MASK) return ERR_PTR(-EINVAL); stab = kzalloc(sizeof(*stab), GFP_USER); if (!stab) return ERR_PTR(-ENOMEM); bpf_map_init_from_attr(&stab->map, attr); raw_spin_lock_init(&stab->lock); /* Make sure page count doesn't overflow. */ cost = (u64) stab->map.max_entries * sizeof(struct sock *); err = bpf_map_charge_init(&stab->map.memory, cost); if (err) goto free_stab; stab->sks = bpf_map_area_alloc(stab->map.max_entries * sizeof(struct sock *), stab->map.numa_node); if (stab->sks) return &stab->map; err = -ENOMEM; bpf_map_charge_finish(&stab->map.memory); free_stab: kfree(stab); return ERR_PTR(err); } int sock_map_get_from_fd(const union bpf_attr *attr, struct bpf_prog *prog) { u32 ufd = attr->target_fd; struct bpf_map *map; struct fd f; int ret; if (attr->attach_flags || attr->replace_bpf_fd) return -EINVAL; f = fdget(ufd); map = __bpf_map_get(f); if (IS_ERR(map)) return PTR_ERR(map); ret = sock_map_prog_update(map, prog, NULL, attr->attach_type); fdput(f); return ret; } int sock_map_prog_detach(const union bpf_attr *attr, enum bpf_prog_type ptype) { u32 ufd = attr->target_fd; struct bpf_prog *prog; struct bpf_map *map; struct fd f; int ret; if (attr->attach_flags || attr->replace_bpf_fd) return -EINVAL; f = fdget(ufd); map = __bpf_map_get(f); if (IS_ERR(map)) return PTR_ERR(map); prog = bpf_prog_get(attr->attach_bpf_fd); if (IS_ERR(prog)) { ret = PTR_ERR(prog); goto put_map; } if (prog->type != ptype) { ret = -EINVAL; goto put_prog; } ret = sock_map_prog_update(map, NULL, prog, attr->attach_type); put_prog: bpf_prog_put(prog); put_map: fdput(f); return ret; } static void sock_map_sk_acquire(struct sock *sk) __acquires(&sk->sk_lock.slock) { lock_sock(sk); preempt_disable(); rcu_read_lock(); } static void sock_map_sk_release(struct sock *sk) __releases(&sk->sk_lock.slock) { rcu_read_unlock(); preempt_enable(); release_sock(sk); } static void sock_map_add_link(struct sk_psock *psock, struct sk_psock_link *link, struct bpf_map *map, void *link_raw) { link->link_raw = link_raw; link->map = map; spin_lock_bh(&psock->link_lock); list_add_tail(&link->list, &psock->link); spin_unlock_bh(&psock->link_lock); } static void sock_map_del_link(struct sock *sk, struct sk_psock *psock, void *link_raw) { struct sk_psock_link *link, *tmp; bool strp_stop = false; spin_lock_bh(&psock->link_lock); list_for_each_entry_safe(link, tmp, &psock->link, list) { if (link->link_raw == link_raw) { struct bpf_map *map = link->map; struct bpf_stab *stab = container_of(map, struct bpf_stab, map); if (psock->parser.enabled && stab->progs.skb_parser) strp_stop = true; list_del(&link->list); sk_psock_free_link(link); } } spin_unlock_bh(&psock->link_lock); if (strp_stop) { write_lock_bh(&sk->sk_callback_lock); sk_psock_stop_strp(sk, psock); write_unlock_bh(&sk->sk_callback_lock); } } static void sock_map_unref(struct sock *sk, void *link_raw) { struct sk_psock *psock = sk_psock(sk); if (likely(psock)) { sock_map_del_link(sk, psock, link_raw); sk_psock_put(sk, psock); } } static int sock_map_init_proto(struct sock *sk, struct sk_psock *psock) { struct proto *prot; switch (sk->sk_type) { case SOCK_STREAM: prot = tcp_bpf_get_proto(sk, psock); break; case SOCK_DGRAM: prot = udp_bpf_get_proto(sk, psock); break; default: return -EINVAL; } if (IS_ERR(prot)) return PTR_ERR(prot); sk_psock_update_proto(sk, psock, prot); return 0; } static struct sk_psock *sock_map_psock_get_checked(struct sock *sk) { struct sk_psock *psock; rcu_read_lock(); psock = sk_psock(sk); if (psock) { if (sk->sk_prot->close != sock_map_close) { psock = ERR_PTR(-EBUSY); goto out; } if (!refcount_inc_not_zero(&psock->refcnt)) psock = ERR_PTR(-EBUSY); } out: rcu_read_unlock(); return psock; } static int sock_map_link(struct bpf_map *map, struct sk_psock_progs *progs, struct sock *sk) { struct bpf_prog *msg_parser, *skb_parser, *skb_verdict; struct sk_psock *psock; bool skb_progs; int ret; skb_verdict = READ_ONCE(progs->skb_verdict); skb_parser = READ_ONCE(progs->skb_parser); skb_progs = skb_parser && skb_verdict; if (skb_progs) { skb_verdict = bpf_prog_inc_not_zero(skb_verdict); if (IS_ERR(skb_verdict)) return PTR_ERR(skb_verdict); skb_parser = bpf_prog_inc_not_zero(skb_parser); if (IS_ERR(skb_parser)) { bpf_prog_put(skb_verdict); return PTR_ERR(skb_parser); } } msg_parser = READ_ONCE(progs->msg_parser); if (msg_parser) { msg_parser = bpf_prog_inc_not_zero(msg_parser); if (IS_ERR(msg_parser)) { ret = PTR_ERR(msg_parser); goto out; } } psock = sock_map_psock_get_checked(sk); if (IS_ERR(psock)) { ret = PTR_ERR(psock); goto out_progs; } if (psock) { if ((msg_parser && READ_ONCE(psock->progs.msg_parser)) || (skb_progs && READ_ONCE(psock->progs.skb_parser))) { sk_psock_put(sk, psock); ret = -EBUSY; goto out_progs; } } else { psock = sk_psock_init(sk, map->numa_node); if (IS_ERR(psock)) { ret = PTR_ERR(psock); goto out_progs; } } if (msg_parser) psock_set_prog(&psock->progs.msg_parser, msg_parser); ret = sock_map_init_proto(sk, psock); if (ret < 0) goto out_drop; write_lock_bh(&sk->sk_callback_lock); if (skb_progs && !psock->parser.enabled) { ret = sk_psock_init_strp(sk, psock); if (ret) { write_unlock_bh(&sk->sk_callback_lock); goto out_drop; } psock_set_prog(&psock->progs.skb_verdict, skb_verdict); psock_set_prog(&psock->progs.skb_parser, skb_parser); sk_psock_start_strp(sk, psock); } write_unlock_bh(&sk->sk_callback_lock); return 0; out_drop: sk_psock_put(sk, psock); out_progs: if (msg_parser) bpf_prog_put(msg_parser); out: if (skb_progs) { bpf_prog_put(skb_verdict); bpf_prog_put(skb_parser); } return ret; } static int sock_map_link_no_progs(struct bpf_map *map, struct sock *sk) { struct sk_psock *psock; int ret; psock = sock_map_psock_get_checked(sk); if (IS_ERR(psock)) return PTR_ERR(psock); if (!psock) { psock = sk_psock_init(sk, map->numa_node); if (IS_ERR(psock)) return PTR_ERR(psock); } ret = sock_map_init_proto(sk, psock); if (ret < 0) sk_psock_put(sk, psock); return ret; } static void sock_map_free(struct bpf_map *map) { struct bpf_stab *stab = container_of(map, struct bpf_stab, map); int i; /* After the sync no updates or deletes will be in-flight so it * is safe to walk map and remove entries without risking a race * in EEXIST update case. */ synchronize_rcu(); for (i = 0; i < stab->map.max_entries; i++) { struct sock **psk = &stab->sks[i]; struct sock *sk; sk = xchg(psk, NULL); if (sk) { lock_sock(sk); rcu_read_lock(); sock_map_unref(sk, psk); rcu_read_unlock(); release_sock(sk); } } /* wait for psock readers accessing its map link */ synchronize_rcu(); bpf_map_area_free(stab->sks); kfree(stab); } static void sock_map_release_progs(struct bpf_map *map) { psock_progs_drop(&container_of(map, struct bpf_stab, map)->progs); } static struct sock *__sock_map_lookup_elem(struct bpf_map *map, u32 key) { struct bpf_stab *stab = container_of(map, struct bpf_stab, map); WARN_ON_ONCE(!rcu_read_lock_held()); if (unlikely(key >= map->max_entries)) return NULL; return READ_ONCE(stab->sks[key]); } static void *sock_map_lookup(struct bpf_map *map, void *key) { struct sock *sk; sk = __sock_map_lookup_elem(map, *(u32 *)key); if (!sk || !sk_fullsock(sk)) return NULL; if (sk_is_refcounted(sk) && !refcount_inc_not_zero(&sk->sk_refcnt)) return NULL; return sk; } static void *sock_map_lookup_sys(struct bpf_map *map, void *key) { struct sock *sk; if (map->value_size != sizeof(u64)) return ERR_PTR(-ENOSPC); sk = __sock_map_lookup_elem(map, *(u32 *)key); if (!sk) return ERR_PTR(-ENOENT); sock_gen_cookie(sk); return &sk->sk_cookie; } static int __sock_map_delete(struct bpf_stab *stab, struct sock *sk_test, struct sock **psk) { struct sock *sk; int err = 0; raw_spin_lock_bh(&stab->lock); sk = *psk; if (!sk_test || sk_test == sk) sk = xchg(psk, NULL); if (likely(sk)) sock_map_unref(sk, psk); else err = -EINVAL; raw_spin_unlock_bh(&stab->lock); return err; } static void sock_map_delete_from_link(struct bpf_map *map, struct sock *sk, void *link_raw) { struct bpf_stab *stab = container_of(map, struct bpf_stab, map); __sock_map_delete(stab, sk, link_raw); } static int sock_map_delete_elem(struct bpf_map *map, void *key) { struct bpf_stab *stab = container_of(map, struct bpf_stab, map); u32 i = *(u32 *)key; struct sock **psk; if (unlikely(i >= map->max_entries)) return -EINVAL; psk = &stab->sks[i]; return __sock_map_delete(stab, NULL, psk); } static int sock_map_get_next_key(struct bpf_map *map, void *key, void *next) { struct bpf_stab *stab = container_of(map, struct bpf_stab, map); u32 i = key ? *(u32 *)key : U32_MAX; u32 *key_next = next; if (i == stab->map.max_entries - 1) return -ENOENT; if (i >= stab->map.max_entries) *key_next = 0; else *key_next = i + 1; return 0; } static bool sock_map_redirect_allowed(const struct sock *sk); static int sock_map_update_common(struct bpf_map *map, u32 idx, struct sock *sk, u64 flags) { struct bpf_stab *stab = container_of(map, struct bpf_stab, map); struct sk_psock_link *link; struct sk_psock *psock; struct sock *osk; int ret; WARN_ON_ONCE(!rcu_read_lock_held()); if (unlikely(flags > BPF_EXIST)) return -EINVAL; if (unlikely(idx >= map->max_entries)) return -E2BIG; link = sk_psock_init_link(); if (!link) return -ENOMEM; /* Only sockets we can redirect into/from in BPF need to hold * refs to parser/verdict progs and have their sk_data_ready * and sk_write_space callbacks overridden. */ if (sock_map_redirect_allowed(sk)) ret = sock_map_link(map, &stab->progs, sk); else ret = sock_map_link_no_progs(map, sk); if (ret < 0) goto out_free; psock = sk_psock(sk); WARN_ON_ONCE(!psock); raw_spin_lock_bh(&stab->lock); osk = stab->sks[idx]; if (osk && flags == BPF_NOEXIST) { ret = -EEXIST; goto out_unlock; } else if (!osk && flags == BPF_EXIST) { ret = -ENOENT; goto out_unlock; } sock_map_add_link(psock, link, map, &stab->sks[idx]); stab->sks[idx] = sk; if (osk) sock_map_unref(osk, &stab->sks[idx]); raw_spin_unlock_bh(&stab->lock); return 0; out_unlock: raw_spin_unlock_bh(&stab->lock); if (psock) sk_psock_put(sk, psock); out_free: sk_psock_free_link(link); return ret; } static bool sock_map_op_okay(const struct bpf_sock_ops_kern *ops) { return ops->op == BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB || ops->op == BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB || ops->op == BPF_SOCK_OPS_TCP_LISTEN_CB; } static bool sk_is_tcp(const struct sock *sk) { return sk->sk_type == SOCK_STREAM && sk->sk_protocol == IPPROTO_TCP; } static bool sk_is_udp(const struct sock *sk) { return sk->sk_type == SOCK_DGRAM && sk->sk_protocol == IPPROTO_UDP; } static bool sock_map_redirect_allowed(const struct sock *sk) { return sk_is_tcp(sk) && sk->sk_state != TCP_LISTEN; } static bool sock_map_sk_is_suitable(const struct sock *sk) { return sk_is_tcp(sk) || sk_is_udp(sk); } static bool sock_map_sk_state_allowed(const struct sock *sk) { if (sk_is_tcp(sk)) return (1 << sk->sk_state) & (TCPF_ESTABLISHED | TCPF_LISTEN); else if (sk_is_udp(sk)) return sk_hashed(sk); return false; } static int sock_hash_update_common(struct bpf_map *map, void *key, struct sock *sk, u64 flags); int sock_map_update_elem_sys(struct bpf_map *map, void *key, void *value, u64 flags) { struct socket *sock; struct sock *sk; int ret; u64 ufd; if (map->value_size == sizeof(u64)) ufd = *(u64 *)value; else ufd = *(u32 *)value; if (ufd > S32_MAX) return -EINVAL; sock = sockfd_lookup(ufd, &ret); if (!sock) return ret; sk = sock->sk; if (!sk) { ret = -EINVAL; goto out; } if (!sock_map_sk_is_suitable(sk)) { ret = -EOPNOTSUPP; goto out; } sock_map_sk_acquire(sk); if (!sock_map_sk_state_allowed(sk)) ret = -EOPNOTSUPP; else if (map->map_type == BPF_MAP_TYPE_SOCKMAP) ret = sock_map_update_common(map, *(u32 *)key, sk, flags); else ret = sock_hash_update_common(map, key, sk, flags); sock_map_sk_release(sk); out: fput(sock->file); return ret; } static int sock_map_update_elem(struct bpf_map *map, void *key, void *value, u64 flags) { struct sock *sk = (struct sock *)value; int ret; if (!sock_map_sk_is_suitable(sk)) return -EOPNOTSUPP; local_bh_disable(); bh_lock_sock(sk); if (!sock_map_sk_state_allowed(sk)) ret = -EOPNOTSUPP; else if (map->map_type == BPF_MAP_TYPE_SOCKMAP) ret = sock_map_update_common(map, *(u32 *)key, sk, flags); else ret = sock_hash_update_common(map, key, sk, flags); bh_unlock_sock(sk); local_bh_enable(); return ret; } BPF_CALL_4(bpf_sock_map_update, struct bpf_sock_ops_kern *, sops, struct bpf_map *, map, void *, key, u64, flags) { WARN_ON_ONCE(!rcu_read_lock_held()); if (likely(sock_map_sk_is_suitable(sops->sk) && sock_map_op_okay(sops))) return sock_map_update_common(map, *(u32 *)key, sops->sk, flags); return -EOPNOTSUPP; } const struct bpf_func_proto bpf_sock_map_update_proto = { .func = bpf_sock_map_update, .gpl_only = false, .pkt_access = true, .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_CTX, .arg2_type = ARG_CONST_MAP_PTR, .arg3_type = ARG_PTR_TO_MAP_KEY, .arg4_type = ARG_ANYTHING, }; BPF_CALL_4(bpf_sk_redirect_map, struct sk_buff *, skb, struct bpf_map *, map, u32, key, u64, flags) { struct tcp_skb_cb *tcb = TCP_SKB_CB(skb); struct sock *sk; if (unlikely(flags & ~(BPF_F_INGRESS))) return SK_DROP; sk = __sock_map_lookup_elem(map, key); if (unlikely(!sk || !sock_map_redirect_allowed(sk))) return SK_DROP; tcb->bpf.flags = flags; tcb->bpf.sk_redir = sk; return SK_PASS; } const struct bpf_func_proto bpf_sk_redirect_map_proto = { .func = bpf_sk_redirect_map, .gpl_only = false, .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_CTX, .arg2_type = ARG_CONST_MAP_PTR, .arg3_type = ARG_ANYTHING, .arg4_type = ARG_ANYTHING, }; BPF_CALL_4(bpf_msg_redirect_map, struct sk_msg *, msg, struct bpf_map *, map, u32, key, u64, flags) { struct sock *sk; if (unlikely(flags & ~(BPF_F_INGRESS))) return SK_DROP; sk = __sock_map_lookup_elem(map, key); if (unlikely(!sk || !sock_map_redirect_allowed(sk))) return SK_DROP; msg->flags = flags; msg->sk_redir = sk; return SK_PASS; } const struct bpf_func_proto bpf_msg_redirect_map_proto = { .func = bpf_msg_redirect_map, .gpl_only = false, .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_CTX, .arg2_type = ARG_CONST_MAP_PTR, .arg3_type = ARG_ANYTHING, .arg4_type = ARG_ANYTHING, }; static int sock_map_btf_id; const struct bpf_map_ops sock_map_ops = { .map_meta_equal = bpf_map_meta_equal, .map_alloc = sock_map_alloc, .map_free = sock_map_free, .map_get_next_key = sock_map_get_next_key, .map_lookup_elem_sys_only = sock_map_lookup_sys, .map_update_elem = sock_map_update_elem, .map_delete_elem = sock_map_delete_elem, .map_lookup_elem = sock_map_lookup, .map_release_uref = sock_map_release_progs, .map_check_btf = map_check_no_btf, .map_btf_name = "bpf_stab", .map_btf_id = &sock_map_btf_id, }; struct bpf_shtab_elem { struct rcu_head rcu; u32 hash; struct sock *sk; struct hlist_node node; u8 key[]; }; struct bpf_shtab_bucket { struct hlist_head head; raw_spinlock_t lock; }; struct bpf_shtab { struct bpf_map map; struct bpf_shtab_bucket *buckets; u32 buckets_num; u32 elem_size; struct sk_psock_progs progs; atomic_t count; }; static inline u32 sock_hash_bucket_hash(const void *key, u32 len) { return jhash(key, len, 0); } static struct bpf_shtab_bucket *sock_hash_select_bucket(struct bpf_shtab *htab, u32 hash) { return &htab->buckets[hash & (htab->buckets_num - 1)]; } static struct bpf_shtab_elem * sock_hash_lookup_elem_raw(struct hlist_head *head, u32 hash, void *key, u32 key_size) { struct bpf_shtab_elem *elem; hlist_for_each_entry_rcu(elem, head, node) { if (elem->hash == hash && !memcmp(&elem->key, key, key_size)) return elem; } return NULL; } static struct sock *__sock_hash_lookup_elem(struct bpf_map *map, void *key) { struct bpf_shtab *htab = container_of(map, struct bpf_shtab, map); u32 key_size = map->key_size, hash; struct bpf_shtab_bucket *bucket; struct bpf_shtab_elem *elem; WARN_ON_ONCE(!rcu_read_lock_held()); hash = sock_hash_bucket_hash(key, key_size); bucket = sock_hash_select_bucket(htab, hash); elem = sock_hash_lookup_elem_raw(&bucket->head, hash, key, key_size); return elem ? elem->sk : NULL; } static void sock_hash_free_elem(struct bpf_shtab *htab, struct bpf_shtab_elem *elem) { atomic_dec(&htab->count); kfree_rcu(elem, rcu); } static void sock_hash_delete_from_link(struct bpf_map *map, struct sock *sk, void *link_raw) { struct bpf_shtab *htab = container_of(map, struct bpf_shtab, map); struct bpf_shtab_elem *elem_probe, *elem = link_raw; struct bpf_shtab_bucket *bucket; WARN_ON_ONCE(!rcu_read_lock_held()); bucket = sock_hash_select_bucket(htab, elem->hash); /* elem may be deleted in parallel from the map, but access here * is okay since it's going away only after RCU grace period. * However, we need to check whether it's still present. */ raw_spin_lock_bh(&bucket->lock); elem_probe = sock_hash_lookup_elem_raw(&bucket->head, elem->hash, elem->key, map->key_size); if (elem_probe && elem_probe == elem) { hlist_del_rcu(&elem->node); sock_map_unref(elem->sk, elem); sock_hash_free_elem(htab, elem); } raw_spin_unlock_bh(&bucket->lock); } static int sock_hash_delete_elem(struct bpf_map *map, void *key) { struct bpf_shtab *htab = container_of(map, struct bpf_shtab, map); u32 hash, key_size = map->key_size; struct bpf_shtab_bucket *bucket; struct bpf_shtab_elem *elem; int ret = -ENOENT; hash = sock_hash_bucket_hash(key, key_size); bucket = sock_hash_select_bucket(htab, hash); raw_spin_lock_bh(&bucket->lock); elem = sock_hash_lookup_elem_raw(&bucket->head, hash, key, key_size); if (elem) { hlist_del_rcu(&elem->node); sock_map_unref(elem->sk, elem); sock_hash_free_elem(htab, elem); ret = 0; } raw_spin_unlock_bh(&bucket->lock); return ret; } static struct bpf_shtab_elem *sock_hash_alloc_elem(struct bpf_shtab *htab, void *key, u32 key_size, u32 hash, struct sock *sk, struct bpf_shtab_elem *old) { struct bpf_shtab_elem *new; if (atomic_inc_return(&htab->count) > htab->map.max_entries) { if (!old) { atomic_dec(&htab->count); return ERR_PTR(-E2BIG); } } new = kmalloc_node(htab->elem_size, GFP_ATOMIC | __GFP_NOWARN, htab->map.numa_node); if (!new) { atomic_dec(&htab->count); return ERR_PTR(-ENOMEM); } memcpy(new->key, key, key_size); new->sk = sk; new->hash = hash; return new; } static int sock_hash_update_common(struct bpf_map *map, void *key, struct sock *sk, u64 flags) { struct bpf_shtab *htab = container_of(map, struct bpf_shtab, map); u32 key_size = map->key_size, hash; struct bpf_shtab_elem *elem, *elem_new; struct bpf_shtab_bucket *bucket; struct sk_psock_link *link; struct sk_psock *psock; int ret; WARN_ON_ONCE(!rcu_read_lock_held()); if (unlikely(flags > BPF_EXIST)) return -EINVAL; link = sk_psock_init_link(); if (!link) return -ENOMEM; /* Only sockets we can redirect into/from in BPF need to hold * refs to parser/verdict progs and have their sk_data_ready * and sk_write_space callbacks overridden. */ if (sock_map_redirect_allowed(sk)) ret = sock_map_link(map, &htab->progs, sk); else ret = sock_map_link_no_progs(map, sk); if (ret < 0) goto out_free; psock = sk_psock(sk); WARN_ON_ONCE(!psock); hash = sock_hash_bucket_hash(key, key_size); bucket = sock_hash_select_bucket(htab, hash); raw_spin_lock_bh(&bucket->lock); elem = sock_hash_lookup_elem_raw(&bucket->head, hash, key, key_size); if (elem && flags == BPF_NOEXIST) { ret = -EEXIST; goto out_unlock; } else if (!elem && flags == BPF_EXIST) { ret = -ENOENT; goto out_unlock; } elem_new = sock_hash_alloc_elem(htab, key, key_size, hash, sk, elem); if (IS_ERR(elem_new)) { ret = PTR_ERR(elem_new); goto out_unlock; } sock_map_add_link(psock, link, map, elem_new); /* Add new element to the head of the list, so that * concurrent search will find it before old elem. */ hlist_add_head_rcu(&elem_new->node, &bucket->head); if (elem) { hlist_del_rcu(&elem->node); sock_map_unref(elem->sk, elem); sock_hash_free_elem(htab, elem); } raw_spin_unlock_bh(&bucket->lock); return 0; out_unlock: raw_spin_unlock_bh(&bucket->lock); sk_psock_put(sk, psock); out_free: sk_psock_free_link(link); return ret; } static int sock_hash_get_next_key(struct bpf_map *map, void *key, void *key_next) { struct bpf_shtab *htab = container_of(map, struct bpf_shtab, map); struct bpf_shtab_elem *elem, *elem_next; u32 hash, key_size = map->key_size; struct hlist_head *head; int i = 0; if (!key) goto find_first_elem; hash = sock_hash_bucket_hash(key, key_size); head = &sock_hash_select_bucket(htab, hash)->head; elem = sock_hash_lookup_elem_raw(head, hash, key, key_size); if (!elem) goto find_first_elem; elem_next = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu(&elem->node)), struct bpf_shtab_elem, node); if (elem_next) { memcpy(key_next, elem_next->key, key_size); return 0; } i = hash & (htab->buckets_num - 1); i++; find_first_elem: for (; i < htab->buckets_num; i++) { head = &sock_hash_select_bucket(htab, i)->head; elem_next = hlist_entry_safe(rcu_dereference_raw(hlist_first_rcu(head)), struct bpf_shtab_elem, node); if (elem_next) { memcpy(key_next, elem_next->key, key_size); return 0; } } return -ENOENT; } static struct bpf_map *sock_hash_alloc(union bpf_attr *attr) { struct bpf_shtab *htab; int i, err; u64 cost; if (!capable(CAP_NET_ADMIN)) return ERR_PTR(-EPERM); if (attr->max_entries == 0 || attr->key_size == 0 || (attr->value_size != sizeof(u32) && attr->value_size != sizeof(u64)) || attr->map_flags & ~SOCK_CREATE_FLAG_MASK) return ERR_PTR(-EINVAL); if (attr->key_size > MAX_BPF_STACK) return ERR_PTR(-E2BIG); htab = kzalloc(sizeof(*htab), GFP_USER); if (!htab) return ERR_PTR(-ENOMEM); bpf_map_init_from_attr(&htab->map, attr); htab->buckets_num = roundup_pow_of_two(htab->map.max_entries); htab->elem_size = sizeof(struct bpf_shtab_elem) + round_up(htab->map.key_size, 8); if (htab->buckets_num == 0 || htab->buckets_num > U32_MAX / sizeof(struct bpf_shtab_bucket)) { err = -EINVAL; goto free_htab; } cost = (u64) htab->buckets_num * sizeof(struct bpf_shtab_bucket) + (u64) htab->elem_size * htab->map.max_entries; if (cost >= U32_MAX - PAGE_SIZE) { err = -EINVAL; goto free_htab; } err = bpf_map_charge_init(&htab->map.memory, cost); if (err) goto free_htab; htab->buckets = bpf_map_area_alloc(htab->buckets_num * sizeof(struct bpf_shtab_bucket), htab->map.numa_node); if (!htab->buckets) { bpf_map_charge_finish(&htab->map.memory); err = -ENOMEM; goto free_htab; } for (i = 0; i < htab->buckets_num; i++) { INIT_HLIST_HEAD(&htab->buckets[i].head); raw_spin_lock_init(&htab->buckets[i].lock); } return &htab->map; free_htab: kfree(htab); return ERR_PTR(err); } static void sock_hash_free(struct bpf_map *map) { struct bpf_shtab *htab = container_of(map, struct bpf_shtab, map); struct bpf_shtab_bucket *bucket; struct hlist_head unlink_list; struct bpf_shtab_elem *elem; struct hlist_node *node; int i; /* After the sync no updates or deletes will be in-flight so it * is safe to walk map and remove entries without risking a race * in EEXIST update case. */ synchronize_rcu(); for (i = 0; i < htab->buckets_num; i++) { bucket = sock_hash_select_bucket(htab, i); /* We are racing with sock_hash_delete_from_link to * enter the spin-lock critical section. Every socket on * the list is still linked to sockhash. Since link * exists, psock exists and holds a ref to socket. That * lets us to grab a socket ref too. */ raw_spin_lock_bh(&bucket->lock); hlist_for_each_entry(elem, &bucket->head, node) sock_hold(elem->sk); hlist_move_list(&bucket->head, &unlink_list); raw_spin_unlock_bh(&bucket->lock); /* Process removed entries out of atomic context to * block for socket lock before deleting the psock's * link to sockhash. */ hlist_for_each_entry_safe(elem, node, &unlink_list, node) { hlist_del(&elem->node); lock_sock(elem->sk); rcu_read_lock(); sock_map_unref(elem->sk, elem); rcu_read_unlock(); release_sock(elem->sk); sock_put(elem->sk); sock_hash_free_elem(htab, elem); } } /* wait for psock readers accessing its map link */ synchronize_rcu(); bpf_map_area_free(htab->buckets); kfree(htab); } static void *sock_hash_lookup_sys(struct bpf_map *map, void *key) { struct sock *sk; if (map->value_size != sizeof(u64)) return ERR_PTR(-ENOSPC); sk = __sock_hash_lookup_elem(map, key); if (!sk) return ERR_PTR(-ENOENT); sock_gen_cookie(sk); return &sk->sk_cookie; } static void *sock_hash_lookup(struct bpf_map *map, void *key) { struct sock *sk; sk = __sock_hash_lookup_elem(map, key); if (!sk || !sk_fullsock(sk)) return NULL; if (sk_is_refcounted(sk) && !refcount_inc_not_zero(&sk->sk_refcnt)) return NULL; return sk; } static void sock_hash_release_progs(struct bpf_map *map) { psock_progs_drop(&container_of(map, struct bpf_shtab, map)->progs); } BPF_CALL_4(bpf_sock_hash_update, struct bpf_sock_ops_kern *, sops, struct bpf_map *, map, void *, key, u64, flags) { WARN_ON_ONCE(!rcu_read_lock_held()); if (likely(sock_map_sk_is_suitable(sops->sk) && sock_map_op_okay(sops))) return sock_hash_update_common(map, key, sops->sk, flags); return -EOPNOTSUPP; } const struct bpf_func_proto bpf_sock_hash_update_proto = { .func = bpf_sock_hash_update, .gpl_only = false, .pkt_access = true, .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_CTX, .arg2_type = ARG_CONST_MAP_PTR, .arg3_type = ARG_PTR_TO_MAP_KEY, .arg4_type = ARG_ANYTHING, }; BPF_CALL_4(bpf_sk_redirect_hash, struct sk_buff *, skb, struct bpf_map *, map, void *, key, u64, flags) { struct tcp_skb_cb *tcb = TCP_SKB_CB(skb); struct sock *sk; if (unlikely(flags & ~(BPF_F_INGRESS))) return SK_DROP; sk = __sock_hash_lookup_elem(map, key); if (unlikely(!sk || !sock_map_redirect_allowed(sk))) return SK_DROP; tcb->bpf.flags = flags; tcb->bpf.sk_redir = sk; return SK_PASS; } const struct bpf_func_proto bpf_sk_redirect_hash_proto = { .func = bpf_sk_redirect_hash, .gpl_only = false, .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_CTX, .arg2_type = ARG_CONST_MAP_PTR, .arg3_type = ARG_PTR_TO_MAP_KEY, .arg4_type = ARG_ANYTHING, }; BPF_CALL_4(bpf_msg_redirect_hash, struct sk_msg *, msg, struct bpf_map *, map, void *, key, u64, flags) { struct sock *sk; if (unlikely(flags & ~(BPF_F_INGRESS))) return SK_DROP; sk = __sock_hash_lookup_elem(map, key); if (unlikely(!sk || !sock_map_redirect_allowed(sk))) return SK_DROP; msg->flags = flags; msg->sk_redir = sk; return SK_PASS; } const struct bpf_func_proto bpf_msg_redirect_hash_proto = { .func = bpf_msg_redirect_hash, .gpl_only = false, .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_CTX, .arg2_type = ARG_CONST_MAP_PTR, .arg3_type = ARG_PTR_TO_MAP_KEY, .arg4_type = ARG_ANYTHING, }; static int sock_hash_map_btf_id; const struct bpf_map_ops sock_hash_ops = { .map_meta_equal = bpf_map_meta_equal, .map_alloc = sock_hash_alloc, .map_free = sock_hash_free, .map_get_next_key = sock_hash_get_next_key, .map_update_elem = sock_map_update_elem, .map_delete_elem = sock_hash_delete_elem, .map_lookup_elem = sock_hash_lookup, .map_lookup_elem_sys_only = sock_hash_lookup_sys, .map_release_uref = sock_hash_release_progs, .map_check_btf = map_check_no_btf, .map_btf_name = "bpf_shtab", .map_btf_id = &sock_hash_map_btf_id, }; static struct sk_psock_progs *sock_map_progs(struct bpf_map *map) { switch (map->map_type) { case BPF_MAP_TYPE_SOCKMAP: return &container_of(map, struct bpf_stab, map)->progs; case BPF_MAP_TYPE_SOCKHASH: return &container_of(map, struct bpf_shtab, map)->progs; default: break; } return NULL; } int sock_map_prog_update(struct bpf_map *map, struct bpf_prog *prog, struct bpf_prog *old, u32 which) { struct sk_psock_progs *progs = sock_map_progs(map); struct bpf_prog **pprog; if (!progs) return -EOPNOTSUPP; switch (which) { case BPF_SK_MSG_VERDICT: pprog = &progs->msg_parser; break; case BPF_SK_SKB_STREAM_PARSER: pprog = &progs->skb_parser; break; case BPF_SK_SKB_STREAM_VERDICT: pprog = &progs->skb_verdict; break; default: return -EOPNOTSUPP; } if (old) return psock_replace_prog(pprog, prog, old); psock_set_prog(pprog, prog); return 0; } static void sock_map_unlink(struct sock *sk, struct sk_psock_link *link) { switch (link->map->map_type) { case BPF_MAP_TYPE_SOCKMAP: return sock_map_delete_from_link(link->map, sk, link->link_raw); case BPF_MAP_TYPE_SOCKHASH: return sock_hash_delete_from_link(link->map, sk, link->link_raw); default: break; } } static void sock_map_remove_links(struct sock *sk, struct sk_psock *psock) { struct sk_psock_link *link; while ((link = sk_psock_link_pop(psock))) { sock_map_unlink(sk, link); sk_psock_free_link(link); } } void sock_map_unhash(struct sock *sk) { void (*saved_unhash)(struct sock *sk); struct sk_psock *psock; rcu_read_lock(); psock = sk_psock(sk); if (unlikely(!psock)) { rcu_read_unlock(); if (sk->sk_prot->unhash) sk->sk_prot->unhash(sk); return; } saved_unhash = psock->saved_unhash; sock_map_remove_links(sk, psock); rcu_read_unlock(); saved_unhash(sk); } void sock_map_close(struct sock *sk, long timeout) { void (*saved_close)(struct sock *sk, long timeout); struct sk_psock *psock; lock_sock(sk); rcu_read_lock(); psock = sk_psock(sk); if (unlikely(!psock)) { rcu_read_unlock(); release_sock(sk); return sk->sk_prot->close(sk, timeout); } saved_close = psock->saved_close; sock_map_remove_links(sk, psock); rcu_read_unlock(); release_sock(sk); saved_close(sk, timeout); }
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