1 files changed, 53 insertions, 20 deletions

diff --git a/net/ipv4/tcp_ulp.c b/net/ipv4/tcp_ulp.c
index 2417f55374c5..2aa442128630 100644
--- a/net/ipv4/tcp_ulp.c
+++ b/net/ipv4/tcp_ulp.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Pluggable TCP upper layer protocol support.
  *
@@ -6,7 +7,7 @@
  *
  */
 
-#include<linux/module.h>
+#include <linux/module.h>
 #include <linux/mm.h>
 #include <linux/types.h>
 #include <linux/list.h>
@@ -21,7 +22,8 @@ static struct tcp_ulp_ops *tcp_ulp_find(const char *name)
 {
 	struct tcp_ulp_ops *e;
 
-	list_for_each_entry_rcu(e, &tcp_ulp_list, list) {
+	list_for_each_entry_rcu(e, &tcp_ulp_list, list,
+				lockdep_is_held(&tcp_ulp_list_lock)) {
 		if (strcmp(e->name, name) == 0)
 			return e;
 	}
@@ -39,7 +41,7 @@ static const struct tcp_ulp_ops *__tcp_ulp_find_autoload(const char *name)
 #ifdef CONFIG_MODULES
 	if (!ulp && capable(CAP_NET_ADMIN)) {
 		rcu_read_unlock();
-		request_module("%s", name);
+		request_module("tcp-ulp-%s", name);
 		rcu_read_lock();
 		ulp = tcp_ulp_find(name);
 	}
@@ -59,13 +61,10 @@ int tcp_register_ulp(struct tcp_ulp_ops *ulp)
 	int ret = 0;
 
 	spin_lock(&tcp_ulp_list_lock);
-	if (tcp_ulp_find(ulp->name)) {
-		pr_notice("%s already registered or non-unique name\n",
-			  ulp->name);
+	if (tcp_ulp_find(ulp->name))
 		ret = -EEXIST;
-	} else {
+	else
 		list_add_tail_rcu(&ulp->list, &tcp_ulp_list);
-	}
 	spin_unlock(&tcp_ulp_list_lock);
 
 	return ret;
@@ -94,42 +93,76 @@ void tcp_get_available_ulp(char *buf, size_t maxlen)
 		offs += snprintf(buf + offs, maxlen - offs,
 				 "%s%s",
 				 offs == 0 ? "" : " ", ulp_ops->name);
+
+		if (WARN_ON_ONCE(offs >= maxlen))
+			break;
 	}
 	rcu_read_unlock();
 }
 
+void tcp_update_ulp(struct sock *sk, struct proto *proto,
+		    void (*write_space)(struct sock *sk))
+{
+	struct inet_connection_sock *icsk = inet_csk(sk);
+
+	if (icsk->icsk_ulp_ops->update)
+		icsk->icsk_ulp_ops->update(sk, proto, write_space);
+}
+
 void tcp_cleanup_ulp(struct sock *sk)
 {
 	struct inet_connection_sock *icsk = inet_csk(sk);
 
+	/* No sock_owned_by_me() check here as at the time the
+	 * stack calls this function, the socket is dead and
+	 * about to be destroyed.
+	 */
 	if (!icsk->icsk_ulp_ops)
 		return;
 
 	if (icsk->icsk_ulp_ops->release)
 		icsk->icsk_ulp_ops->release(sk);
 	module_put(icsk->icsk_ulp_ops->owner);
+
+	icsk->icsk_ulp_ops = NULL;
 }
 
-/* Change upper layer protocol for socket */
-int tcp_set_ulp(struct sock *sk, const char *name)
+static int __tcp_set_ulp(struct sock *sk, const struct tcp_ulp_ops *ulp_ops)
 {
 	struct inet_connection_sock *icsk = inet_csk(sk);
-	const struct tcp_ulp_ops *ulp_ops;
-	int err = 0;
+	int err;
 
+	err = -EEXIST;
 	if (icsk->icsk_ulp_ops)
-		return -EEXIST;
+		goto out_err;
 
-	ulp_ops = __tcp_ulp_find_autoload(name);
-	if (!ulp_ops)
-		err = -ENOENT;
-	else
-		err = ulp_ops->init(sk);
+	if (sk->sk_socket)
+		clear_bit(SOCK_SUPPORT_ZC, &sk->sk_socket->flags);
+
+	err = -ENOTCONN;
+	if (!ulp_ops->clone && sk->sk_state == TCP_LISTEN)
+		goto out_err;
 
+	err = ulp_ops->init(sk);
 	if (err)
-		goto out;
+		goto out_err;
 
 	icsk->icsk_ulp_ops = ulp_ops;
- out:
+	return 0;
+out_err:
+	module_put(ulp_ops->owner);
 	return err;
 }
+
+int tcp_set_ulp(struct sock *sk, const char *name)
+{
+	const struct tcp_ulp_ops *ulp_ops;
+
+	sock_owned_by_me(sk);
+
+	ulp_ops = __tcp_ulp_find_autoload(name);
+	if (!ulp_ops)
+		return -ENOENT;
+
+	return __tcp_set_ulp(sk, ulp_ops);
+}