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95fa145479
When a map free is called and in parallel a socket is closed we
have two paths that can potentially reset the socket prot ops, the
bpf close() path and the map free path. This creates a problem
with which prot ops should be used from the socket closed side.
If the map_free side completes first then we want to call the
original lowest level ops. However, if the tls path runs first
we want to call the sockmap ops. Additionally there was no locking
around prot updates in TLS code paths so the prot ops could
be changed multiple times once from TLS path and again from sockmap
side potentially leaving ops pointed at either TLS or sockmap
when psock and/or tls context have already been destroyed.
To fix this race first only update ops inside callback lock
so that TLS, sockmap and lowest level all agree on prot state.
Second and a ULP callback update() so that lower layers can
inform the upper layer when they are being removed allowing the
upper layer to reset prot ops.
This gets us close to allowing sockmap and tls to be stacked
in arbitrary order but will save that patch for *next trees.
v4:
- make sure we don't free things for device;
- remove the checks which swap the callbacks back
only if TLS is at the top.
Reported-by: syzbot+06537213db7ba2745c4a@syzkaller.appspotmail.com
Fixes: 02c558b2d5 ("bpf: sockmap, support for msg_peek in sk_msg with redirect ingress")
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
162 lines
3.3 KiB
C
162 lines
3.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Pluggable TCP upper layer protocol support.
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*
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* Copyright (c) 2016-2017, Mellanox Technologies. All rights reserved.
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* Copyright (c) 2016-2017, Dave Watson <davejwatson@fb.com>. All rights reserved.
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*
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*/
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#include <linux/module.h>
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#include <linux/mm.h>
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#include <linux/types.h>
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#include <linux/list.h>
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#include <linux/gfp.h>
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#include <net/tcp.h>
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static DEFINE_SPINLOCK(tcp_ulp_list_lock);
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static LIST_HEAD(tcp_ulp_list);
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/* Simple linear search, don't expect many entries! */
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static struct tcp_ulp_ops *tcp_ulp_find(const char *name)
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{
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struct tcp_ulp_ops *e;
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list_for_each_entry_rcu(e, &tcp_ulp_list, list) {
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if (strcmp(e->name, name) == 0)
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return e;
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}
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return NULL;
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}
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static const struct tcp_ulp_ops *__tcp_ulp_find_autoload(const char *name)
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{
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const struct tcp_ulp_ops *ulp = NULL;
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rcu_read_lock();
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ulp = tcp_ulp_find(name);
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#ifdef CONFIG_MODULES
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if (!ulp && capable(CAP_NET_ADMIN)) {
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rcu_read_unlock();
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request_module("tcp-ulp-%s", name);
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rcu_read_lock();
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ulp = tcp_ulp_find(name);
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}
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#endif
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if (!ulp || !try_module_get(ulp->owner))
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ulp = NULL;
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rcu_read_unlock();
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return ulp;
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}
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/* Attach new upper layer protocol to the list
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* of available protocols.
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*/
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int tcp_register_ulp(struct tcp_ulp_ops *ulp)
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{
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int ret = 0;
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spin_lock(&tcp_ulp_list_lock);
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if (tcp_ulp_find(ulp->name))
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ret = -EEXIST;
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else
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list_add_tail_rcu(&ulp->list, &tcp_ulp_list);
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spin_unlock(&tcp_ulp_list_lock);
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return ret;
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}
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EXPORT_SYMBOL_GPL(tcp_register_ulp);
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void tcp_unregister_ulp(struct tcp_ulp_ops *ulp)
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{
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spin_lock(&tcp_ulp_list_lock);
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list_del_rcu(&ulp->list);
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spin_unlock(&tcp_ulp_list_lock);
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synchronize_rcu();
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}
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EXPORT_SYMBOL_GPL(tcp_unregister_ulp);
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/* Build string with list of available upper layer protocl values */
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void tcp_get_available_ulp(char *buf, size_t maxlen)
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{
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struct tcp_ulp_ops *ulp_ops;
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size_t offs = 0;
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*buf = '\0';
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rcu_read_lock();
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list_for_each_entry_rcu(ulp_ops, &tcp_ulp_list, list) {
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offs += snprintf(buf + offs, maxlen - offs,
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"%s%s",
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offs == 0 ? "" : " ", ulp_ops->name);
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}
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rcu_read_unlock();
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}
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void tcp_update_ulp(struct sock *sk, struct proto *proto)
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{
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struct inet_connection_sock *icsk = inet_csk(sk);
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if (!icsk->icsk_ulp_ops) {
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sk->sk_prot = proto;
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return;
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}
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if (icsk->icsk_ulp_ops->update)
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icsk->icsk_ulp_ops->update(sk, proto);
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}
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void tcp_cleanup_ulp(struct sock *sk)
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{
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struct inet_connection_sock *icsk = inet_csk(sk);
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/* No sock_owned_by_me() check here as at the time the
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* stack calls this function, the socket is dead and
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* about to be destroyed.
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*/
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if (!icsk->icsk_ulp_ops)
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return;
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if (icsk->icsk_ulp_ops->release)
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icsk->icsk_ulp_ops->release(sk);
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module_put(icsk->icsk_ulp_ops->owner);
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icsk->icsk_ulp_ops = NULL;
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}
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static int __tcp_set_ulp(struct sock *sk, const struct tcp_ulp_ops *ulp_ops)
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{
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struct inet_connection_sock *icsk = inet_csk(sk);
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int err;
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err = -EEXIST;
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if (icsk->icsk_ulp_ops)
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goto out_err;
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err = ulp_ops->init(sk);
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if (err)
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goto out_err;
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icsk->icsk_ulp_ops = ulp_ops;
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return 0;
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out_err:
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module_put(ulp_ops->owner);
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return err;
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}
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int tcp_set_ulp(struct sock *sk, const char *name)
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{
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const struct tcp_ulp_ops *ulp_ops;
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sock_owned_by_me(sk);
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ulp_ops = __tcp_ulp_find_autoload(name);
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if (!ulp_ops)
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return -ENOENT;
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return __tcp_set_ulp(sk, ulp_ops);
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}
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