Commit 16942cf4 authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by Jakub Kicinski
Browse files

sctp: Use sk_clone() in sctp_accept(). 



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_v4_create_accept_sk() allocates sk by sk_alloc(), initialises
it by sock_init_data(), and copy a bunch of fields from the parent
socekt by sctp_copy_sock().

sctp_sock_migrate() calls sctp_copy_descendant() to copy most fields
in sctp_sock from the parent socket by memcpy().

These can be simply replaced by sk_clone().

Let's consolidate sctp_v[46]_create_accept_sk() to sctp_clone_sock()
with sk_clone().

We will reuse sctp_clone_sock() for sctp_do_peeloff() and then remove
sctp_copy_descendant().

Note that sock_reset_flag(newsk, SOCK_ZAPPED) is not copied to
sctp_clone_sock() as sctp does not use SOCK_ZAPPED at all.

Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@google.com>
Acked-by: default avatarXin Long <lucien.xin@gmail.com>
Link: https://patch.msgid.link/20251023231751.4168390-6-kuniyu@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 151b98d1

net/ipv4/af_inet.c

+1 −3
Original line number Diff line number Diff line
@@ -755,9 +755,7 @@ EXPORT_SYMBOL(inet_stream_connect); 


void __inet_accept(struct socket *sock, struct socket *newsock, struct sock *newsk)

{

	/* TODO: use sk_clone_lock() in SCTP and remove protocol checks */

	if (mem_cgroup_sockets_enabled &&

	    (!IS_ENABLED(CONFIG_IP_SCTP) || sk_is_tcp(newsk))) {

	if (mem_cgroup_sockets_enabled) {

		gfp_t gfp = GFP_KERNEL | __GFP_NOFAIL;



		mem_cgroup_sk_alloc(newsk);

net/sctp/socket.c

+76 −37
Original line number Diff line number Diff line
@@ -4842,6 +4842,74 @@ static int sctp_disconnect(struct sock *sk, int flags) 
	return 0;

}



static struct sock *sctp_clone_sock(struct sock *sk,

				    struct sctp_association *asoc,

				    enum sctp_socket_type type)

{

	struct sock *newsk = sk_clone(sk, GFP_KERNEL, false);

	struct inet_sock *newinet;

	struct sctp_sock *newsp;

	int err = -ENOMEM;



	if (!newsk)

		return ERR_PTR(err);



	/* sk_clone() sets refcnt to 2 */

	sock_put(newsk);



	newinet = inet_sk(newsk);

	newsp = sctp_sk(newsk);



	newsp->pf->to_sk_daddr(&asoc->peer.primary_addr, newsk);

	newinet->inet_dport = htons(asoc->peer.port);



	newsp->pf->copy_ip_options(sk, newsk);

	atomic_set(&newinet->inet_id, get_random_u16());



	inet_set_bit(MC_LOOP, newsk);

	newinet->mc_ttl = 1;

	newinet->mc_index = 0;

	newinet->mc_list = NULL;



#if IS_ENABLED(CONFIG_IPV6)

	if (sk->sk_family == AF_INET6) {

		struct ipv6_pinfo *newnp = inet6_sk(newsk);



		newinet->pinet6 = &((struct sctp6_sock *)newsk)->inet6;

		newinet->ipv6_fl_list = NULL;



		memcpy(newnp, inet6_sk(sk), sizeof(struct ipv6_pinfo));

		newnp->ipv6_mc_list = NULL;

		newnp->ipv6_ac_list = NULL;

	}

#endif



	skb_queue_head_init(&newsp->pd_lobby);



	newsp->ep = sctp_endpoint_new(newsk, GFP_KERNEL);

	if (!newsp->ep)

		goto out_release;



	SCTP_DBG_OBJCNT_INC(sock);

	sk_sockets_allocated_inc(newsk);

	sock_prot_inuse_add(sock_net(sk), newsk->sk_prot, 1);



	err = sctp_sock_migrate(sk, newsk, asoc, type);

	if (err)

		goto out_release;



	/* Set newsk security attributes from original sk and connection

	 * security attribute from asoc.

	 */

	security_sctp_sk_clone(asoc, sk, newsk);



	return newsk;



out_release:

	sk_common_release(newsk);

	return ERR_PTR(err);

}



/* 4.1.4 accept() - TCP Style Syntax

 *

 * Applications use accept() call to remove an established SCTP
@@ -4851,18 +4919,13 @@ 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, *newsp;

	struct sctp_endpoint *ep;

	struct sock *newsk = NULL;

	struct sctp_association *asoc;

	long timeo;

	struct sock *newsk = NULL;

	int error = 0;

	long timeo;



	lock_sock(sk);



	sp = sctp_sk(sk);

	ep = sp->ep;



	if (!sctp_style(sk, TCP)) {

		error = -EOPNOTSUPP;

		goto out;
@@ -4883,43 +4946,19 @@ static struct sock *sctp_accept(struct sock *sk, struct proto_accept_arg *arg) 
	/* We treat the list of associations on the endpoint as the accept

	 * queue and pick the first association on the list.

	 */

	asoc = list_entry(ep->asocs.next, struct sctp_association, asocs);



	newsk = sp->pf->create_accept_sk(sk, asoc, arg->kern);

	if (!newsk) {

		error = -ENOMEM;

		goto out;

	}

	asoc = list_entry(sctp_sk(sk)->ep->asocs.next,

			  struct sctp_association, asocs);



	newsp = sctp_sk(newsk);

	newsp->ep = sctp_endpoint_new(newsk, GFP_KERNEL);

	if (!newsp->ep) {

		error = -ENOMEM;

		goto out_release;

	newsk = sctp_clone_sock(sk, asoc, SCTP_SOCKET_TCP);

	if (IS_ERR(newsk)) {

		error = PTR_ERR(newsk);

		newsk = NULL;

	}



	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)

		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. */