[PATCH v1 net-next 3/8] sctp: Don't call sk->sk_prot->init() in sctp_v[46]_create_accept_sk().
From: Kuniyuki Iwashima <kuniyu@google.com>
Date: 2025-10-21 21:44:29
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_accept() calls sctp_v[46]_create_accept_sk() to allocate a new
socket and calls sctp_sock_migrate() to copy fields from the parent
socket to the new socket.
sctp_v[46]_create_accept_sk() calls sctp_init_sock() to initialise
sctp_sock, but most fields are overwritten by sctp_copy_descendant()
called from sctp_sock_migrate().
Things done in sctp_init_sock() but not in sctp_sock_migrate() are
the following:
1. Copy sk->sk_gso
2. Copy sk->sk_destruct (sctp_v6_init_sock())
3. Allocate sctp_sock.ep
4. Initialise sctp_sock.pd_lobby
5. Count sk_sockets_allocated_inc(), sock_prot_inuse_add(),
and SCTP_DBG_OBJCNT_INC()
Let's do these in sctp_copy_sock() and sctp_sock_migrate() and avoid
calling sk->sk_prot->init() in sctp_v[46]_create_accept_sk().
Note that sk->sk_destruct is already copied in sctp_copy_sock().
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
---
net/sctp/ipv6.c | 8 +-------
net/sctp/protocol.c | 8 +-------
net/sctp/socket.c | 27 ++++++++++++++++++++++-----
3 files changed, 24 insertions(+), 19 deletions(-)
diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
index d725b21587588..c0762424a8544 100644
--- a/net/sctp/ipv6.c
+++ b/net/sctp/ipv6.c@@ -789,7 +789,7 @@ static struct sock *sctp_v6_create_accept_sk(struct sock *sk, newsk = sk_alloc(sock_net(sk), PF_INET6, GFP_KERNEL, sk->sk_prot, kern); if (!newsk) - goto out; + return NULL; sock_init_data(NULL, newsk);
@@ -818,12 +818,6 @@ static struct sock *sctp_v6_create_accept_sk(struct sock *sk, newsk->sk_v6_rcv_saddr = sk->sk_v6_rcv_saddr; - if (newsk->sk_prot->init(newsk)) { - sk_common_release(newsk); - newsk = NULL; - } - -out: return newsk; }
diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
index 9dbc24af749b5..ad2722d1ec150 100644
--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c@@ -590,7 +590,7 @@ static struct sock *sctp_v4_create_accept_sk(struct sock *sk, struct inet_sock *newinet; if (!newsk) - goto out; + return NULL; sock_init_data(NULL, newsk);
@@ -603,12 +603,6 @@ static struct sock *sctp_v4_create_accept_sk(struct sock *sk, newinet->inet_daddr = asoc->peer.primary_addr.v4.sin_addr.s_addr; - if (newsk->sk_prot->init(newsk)) { - sk_common_release(newsk); - newsk = NULL; - } - -out: return newsk; }
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 735b1222af955..70c75ac8da55d 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c@@ -4851,7 +4851,7 @@ static int sctp_disconnect(struct sock *sk, int flags) */ static struct sock *sctp_accept(struct sock *sk, struct proto_accept_arg *arg) { - struct sctp_sock *sp; + struct sctp_sock *sp, *newsp; struct sctp_endpoint *ep; struct sock *newsk = NULL; struct sctp_association *asoc;
@@ -4891,19 +4891,35 @@ static struct sock *sctp_accept(struct sock *sk, struct proto_accept_arg *arg) goto out; } + newsp = sctp_sk(newsk); + newsp->ep = sctp_endpoint_new(newsk, GFP_KERNEL); + if (!newsp->ep) { + error = -ENOMEM; + goto out_release; + } + + skb_queue_head_init(&newsp->pd_lobby); + + sk_sockets_allocated_inc(newsk); + sock_prot_inuse_add(sock_net(sk), newsk->sk_prot, 1); + SCTP_DBG_OBJCNT_INC(sock); + /* Populate the fields of the newsk from the oldsk and migrate the * asoc to the newsk. */ error = sctp_sock_migrate(sk, newsk, asoc, SCTP_SOCKET_TCP); - if (error) { - sk_common_release(newsk); - newsk = NULL; - } + if (error) + goto out_release; out: release_sock(sk); arg->err = error; return newsk; + +out_release: + sk_common_release(newsk); + newsk = NULL; + goto out; } /* The SCTP ioctl handler. */
@@ -9469,6 +9485,7 @@ void sctp_copy_sock(struct sock *newsk, struct sock *sk, newsk->sk_rcvtimeo = READ_ONCE(sk->sk_rcvtimeo); newsk->sk_sndtimeo = READ_ONCE(sk->sk_sndtimeo); newsk->sk_rxhash = sk->sk_rxhash; + newsk->sk_gso_type = sk->sk_gso_type; newinet = inet_sk(newsk);
--
2.51.0.915.g61a8936c21-goog