mirror of
https://github.com/edk2-porting/linux-next.git
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8b9088f806
Whenever the ULP data on the socket is mangled, enforce that the caller has the socket lock held as otherwise things may race with initialization and cleanup callbacks from ulp ops as both would mangle internal socket state. Joint work with John. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
191 lines
3.7 KiB
C
191 lines
3.7 KiB
C
/*
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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 struct tcp_ulp_ops *tcp_ulp_find_id(const int ulp)
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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 (e->uid == ulp)
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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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static const struct tcp_ulp_ops *__tcp_ulp_lookup(const int uid)
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{
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const struct tcp_ulp_ops *ulp;
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rcu_read_lock();
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ulp = tcp_ulp_find_id(uid);
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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_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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sock_owned_by_me(sk);
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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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/* Change upper layer protocol for socket */
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int tcp_set_ulp(struct sock *sk, const char *name)
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{
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struct inet_connection_sock *icsk = inet_csk(sk);
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const struct tcp_ulp_ops *ulp_ops;
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int err = 0;
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sock_owned_by_me(sk);
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if (icsk->icsk_ulp_ops)
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return -EEXIST;
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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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if (!ulp_ops->user_visible) {
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module_put(ulp_ops->owner);
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return -ENOENT;
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}
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err = ulp_ops->init(sk);
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if (err) {
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module_put(ulp_ops->owner);
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return err;
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}
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icsk->icsk_ulp_ops = ulp_ops;
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return 0;
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}
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int tcp_set_ulp_id(struct sock *sk, int ulp)
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{
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struct inet_connection_sock *icsk = inet_csk(sk);
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const struct tcp_ulp_ops *ulp_ops;
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int err;
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sock_owned_by_me(sk);
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if (icsk->icsk_ulp_ops)
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return -EEXIST;
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ulp_ops = __tcp_ulp_lookup(ulp);
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if (!ulp_ops)
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return -ENOENT;
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err = ulp_ops->init(sk);
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if (err) {
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module_put(ulp_ops->owner);
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return err;
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}
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icsk->icsk_ulp_ops = ulp_ops;
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return 0;
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}
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