[PATCH v2 net-next 7/8] sctp: Use sctp_clone_sock() in sctp_do_peeloff().
From: Kuniyuki Iwashima <kuniyu@google.com>
Date: 2025-10-22 21:17:35
Also in:
linux-sctp
Subsystem:
networking [general], sctp protocol, the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Marcelo Ricardo Leitner, Xin Long, Linus Torvalds
sctp_do_peeloff() calls sock_create() to allocate and initialise struct sock, inet_sock, and sctp_sock, but later sctp_copy_sock() and sctp_sock_migrate() overwrite most fields. What sctp_do_peeloff() does is more like accept(). Let's use sock_create_lite() and sctp_clone_sock(). Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> --- v2: Export __inet_accept() --- net/ipv4/af_inet.c | 1 + net/sctp/socket.c | 36 +++++++++++++++--------------------- 2 files changed, 16 insertions(+), 21 deletions(-)
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 77f6ae0fc231..0784e2a873a1 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c@@ -788,6 +788,7 @@ void __inet_accept(struct socket *sock, struct socket *newsock, struct sock *new newsock->state = SS_CONNECTED; } +EXPORT_SYMBOL_GPL(__inet_accept); /* * Accept a pending connection. The TCP layer now gives BSD semantics.
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 826f17747f17..60d3e340dfed 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c@@ -5671,11 +5671,11 @@ static int sctp_getsockopt_autoclose(struct sock *sk, int len, char __user *optv /* Helper routine to branch off an association to a new socket. */ static int sctp_do_peeloff(struct sock *sk, sctp_assoc_t id, - struct socket **sockp) + struct socket **sockp) { struct sctp_association *asoc = sctp_id2assoc(sk, id); - struct sctp_sock *sp = sctp_sk(sk); struct socket *sock; + struct sock *newsk; int err = 0; /* Do not peel off from one netns to another one. */
@@ -5691,30 +5691,24 @@ static int sctp_do_peeloff(struct sock *sk, sctp_assoc_t id, if (!sctp_style(sk, UDP)) return -EINVAL; - /* Create a new socket. */ - err = sock_create(sk->sk_family, SOCK_SEQPACKET, IPPROTO_SCTP, &sock); - if (err < 0) + err = sock_create_lite(sk->sk_family, SOCK_SEQPACKET, IPPROTO_SCTP, &sock); + if (err) return err; - sctp_copy_sock(sock->sk, sk, asoc); - - /* Make peeled-off sockets more like 1-1 accepted sockets. - * Set the daddr and initialize id to something more random and also - * copy over any ip options. - */ - sp->pf->to_sk_daddr(&asoc->peer.primary_addr, sock->sk); - sp->pf->copy_ip_options(sk, sock->sk); - - /* Populate the fields of the newsk from the oldsk and migrate the - * asoc to the newsk. - */ - err = sctp_sock_migrate(sk, sock->sk, asoc, - SCTP_SOCKET_UDP_HIGH_BANDWIDTH); - if (err) { + newsk = sctp_clone_sock(sk, asoc, SCTP_SOCKET_UDP_HIGH_BANDWIDTH); + if (IS_ERR(newsk)) { sock_release(sock); - sock = NULL; + *sockp = NULL; + return PTR_ERR(newsk); } + lock_sock_nested(newsk, SINGLE_DEPTH_NESTING); + __inet_accept(sk->sk_socket, sock, newsk); + release_sock(newsk); + + sock->ops = sk->sk_socket->ops; + __module_get(sock->ops->owner); + *sockp = sock; return err;
--
2.51.1.814.gb8fa24458f-goog