[PATCH net-next 4/5] net: sctp: decouple cleaning socket data from endpoint

[Daniel Borkmann <dborkman@redhat.com>]

Rather instead of having the endpoint clean the garbage for the
socket, use a sk_destruct handler sctp_destruct_sock(), that does
the job for that when there are no more references on the socket.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
---
 net/sctp/endpointola.c |  7 -------
 net/sctp/socket.c      | 20 +++++++++++++++++++-
 2 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/net/sctp/endpointola.c b/net/sctp/endpointola.c
index a8b2674..9a9ebd2 100644
--- a/net/sctp/endpointola.c
+++ b/net/sctp/endpointola.c
@@ -249,9 +249,6 @@ static void sctp_endpoint_destroy(struct sctp_endpoint *ep)
 {
 	SCTP_ASSERT(ep->base.dead, "Endpoint is not dead", return);
 
-	/* Free up the HMAC transform. */
-	crypto_free_hash(sctp_sk(ep->base.sk)->hmac);
-
 	/* Free the digest buffer */
 	kfree(ep->digest);
 
@@ -271,10 +268,6 @@ static void sctp_endpoint_destroy(struct sctp_endpoint *ep)
 
 	memset(ep->secret_key, 0, sizeof(ep->secret_key));
 
-	/* Remove and free the port */
-	if (sctp_sk(ep->base.sk)->bind_hash)
-		sctp_put_port(ep->base.sk);
-
 	/* Give up our hold on the sock. */
 	if (ep->base.sk)
 		sock_put(ep->base.sk);
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 68a6b70..67f721e 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -93,6 +93,7 @@ static int sctp_wait_for_packet(struct sock * sk, int *err, long *timeo_p);
 static int sctp_wait_for_connect(struct sctp_association *, long *timeo_p);
 static int sctp_wait_for_accept(struct sock *sk, long timeo);
 static void sctp_wait_for_close(struct sock *sk, long timeo);
+static void sctp_destruct_sock(struct sock *sk);
 static struct sctp_af *sctp_sockaddr_af(struct sctp_sock *opt,
 					union sctp_addr *addr, int len);
 static int sctp_bindx_add(struct sock *, struct sockaddr *, int);
@@ -3966,6 +3967,8 @@ static int sctp_init_sock(struct sock *sk)
 
 	sp->hmac = NULL;
 
+	sk->sk_destruct = sctp_destruct_sock;
+
 	SCTP_DBG_OBJCNT_INC(sock);
 
 	local_bh_disable();
@@ -4002,6 +4005,21 @@ static void sctp_destroy_sock(struct sock *sk)
 	local_bh_enable();
 }
 
+/* Triggered when there are no references on the socket anymore */
+static void sctp_destruct_sock(struct sock *sk)
+{
+	struct sctp_sock *sp = sctp_sk(sk);
+
+	/* Free up the HMAC transform. */
+	crypto_free_hash(sp->hmac);
+
+	/* Remove and free the port */
+	if (sp->bind_hash)
+		sctp_put_port(sk);
+
+	inet_sock_destruct(sk);
+}
+
 /* API 4.1.7 shutdown() - TCP Style Syntax
  *     int shutdown(int socket, int how);
  *
@@ -6842,7 +6860,7 @@ void sctp_copy_sock(struct sock *newsk, struct sock *sk,
 	newsk->sk_reuse = sk->sk_reuse;
 
 	newsk->sk_shutdown = sk->sk_shutdown;
-	newsk->sk_destruct = inet_sock_destruct;
+	newsk->sk_destruct = sctp_destruct_sock;
 	newsk->sk_family = sk->sk_family;
 	newsk->sk_protocol = IPPROTO_SCTP;
 	newsk->sk_backlog_rcv = sk->sk_prot->backlog_rcv;
-- 
1.7.11.7