path: root/net/ipv6/ipv6_sockglue.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *	IPv6 BSD socket options interface
 *	Linux INET6 implementation
 *
 *	Authors:
 *	Pedro Roque		<roque@di.fc.ul.pt>
 *
 *	Based on linux/net/ipv4/ip_sockglue.c
 *
 *	FIXME: Make the setsockopt code POSIX compliant: That is
 *
 *	o	Truncate getsockopt returns
 *	o	Return an optlen of the truncated length if need be
 *
 *	Changes:
 *	David L Stevens <dlstevens@us.ibm.com>:
 *		- added multicast source filtering API for MLDv2
 */

#include <linux/module.h>
#include <linux/capability.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/in6.h>
#include <linux/mroute6.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/init.h>
#include <linux/sysctl.h>
#include <linux/netfilter.h>
#include <linux/slab.h>

#include <net/sock.h>
#include <net/snmp.h>
#include <net/ipv6.h>
#include <net/ndisc.h>
#include <net/protocol.h>
#include <net/transp_v6.h>
#include <net/ip6_route.h>
#include <net/addrconf.h>
#include <net/inet_common.h>
#include <net/tcp.h>
#include <net/udp.h>
#include <net/udplite.h>
#include <net/xfrm.h>
#include <net/compat.h>
#include <net/seg6.h>

#include <linux/uaccess.h>

struct ip6_ra_chain *ip6_ra_chain;
DEFINE_RWLOCK(ip6_ra_lock);

int ip6_ra_control(struct sock *sk, int sel)
{
	struct ip6_ra_chain *ra, *new_ra, **rap;

	/* RA packet may be delivered ONLY to IPPROTO_RAW socket */
	if (sk->sk_type != SOCK_RAW || inet_sk(sk)->inet_num != IPPROTO_RAW)
		return -ENOPROTOOPT;

	new_ra = (sel >= 0) ? kmalloc(sizeof(*new_ra), GFP_KERNEL) : NULL;
	if (sel >= 0 && !new_ra)
		return -ENOMEM;

	write_lock_bh(&ip6_ra_lock);
	for (rap = &ip6_ra_chain; (ra = *rap) != NULL; rap = &ra->next) {
		if (ra->sk == sk) {
			if (sel >= 0) {
				write_unlock_bh(&ip6_ra_lock);
				kfree(new_ra);
				return -EADDRINUSE;
			}

			*rap = ra->next;
			write_unlock_bh(&ip6_ra_lock);

			sock_put(sk);
			kfree(ra);
			return 0;
		}
	}
	if (!new_ra) {
		write_unlock_bh(&ip6_ra_lock);
		return -ENOBUFS;
	}
	new_ra->sk = sk;
	new_ra->sel = sel;
	new_ra->next = ra;
	*rap = new_ra;
	sock_hold(sk);
	write_unlock_bh(&ip6_ra_lock);
	return 0;
}

struct ipv6_txoptions *ipv6_update_options(struct sock *sk,
					   struct ipv6_txoptions *opt)
{
	if (inet_sk(sk)->is_icsk) {
		if (opt &&
		    !((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)) &&
		    inet_sk(sk)->inet_daddr != LOOPBACK4_IPV6) {
			struct inet_connection_sock *icsk = inet_csk(sk);
			icsk->icsk_ext_hdr_len = opt->opt_flen + opt->opt_nflen;
			icsk->icsk_sync_mss(sk, icsk->icsk_pmtu_cookie);
		}
	}
	opt = xchg((__force struct ipv6_txoptions **)&inet6_sk(sk)->opt,
		   opt);
	sk_dst_reset(sk);

	return opt;
}

static bool setsockopt_needs_rtnl(int optname)
{
	switch (optname) {
	case IPV6_ADDRFORM:
	case IPV6_ADD_MEMBERSHIP:
	case IPV6_DROP_MEMBERSHIP:
	case IPV6_JOIN_ANYCAST:
	case IPV6_LEAVE_ANYCAST:
	case MCAST_JOIN_GROUP:
	case MCAST_LEAVE_GROUP:
	case MCAST_JOIN_SOURCE_GROUP:
	case MCAST_LEAVE_SOURCE_GROUP:
	case MCAST_BLOCK_SOURCE:
	case MCAST_UNBLOCK_SOURCE:
	case MCAST_MSFILTER:
		return true;
	}
	return false;
}

static int do_ipv6_mcast_group_source(struct sock *sk, int optname,
				      struct group_source_req *greqs)
{
	int omode, add;

	if (greqs->gsr_group.ss_family != AF_INET6 ||
	    greqs->gsr_source.ss_family != AF_INET6)
		return -EADDRNOTAVAIL;

	if (optname == MCAST_BLOCK_SOURCE) {
		omode = MCAST_EXCLUDE;
		add = 1;
	} else if (optname == MCAST_UNBLOCK_SOURCE) {
		omode = MCAST_EXCLUDE;
		add = 0;
	} else if (optname == MCAST_JOIN_SOURCE_GROUP) {
		struct sockaddr_in6 *psin6;
		int retv;

		psin6 = (struct sockaddr_in6 *)&greqs->gsr_group;
		retv = ipv6_sock_mc_join_ssm(sk, greqs->gsr_interface,
					     &psin6->sin6_addr,
					     MCAST_INCLUDE);
		/* prior join w/ different source is ok */
		if (retv && retv != -EADDRINUSE)
			return retv;
		omode = MCAST_INCLUDE;
		add = 1;
	} else /* MCAST_LEAVE_SOURCE_GROUP */ {
		omode = MCAST_INCLUDE;
		add = 0;
	}
	return ip6_mc_source(add, omode, sk, greqs);
}

static int do_ipv6_setsockopt(struct sock *sk, int level, int optname,
		    char __user *optval, unsigned int optlen)
{
	struct ipv6_pinfo *np = inet6_sk(sk);
	struct net *net = sock_net(sk);
	int val, valbool;
	int retv = -ENOPROTOOPT;
	bool needs_rtnl = setsockopt_needs_rtnl(optname);

	if (!optval)
		val = 0;
	else {
		if (optlen >= sizeof(int)) {
			if (get_user(val, (int __user *) optval))
				return -EFAULT;
		} else
			val = 0;
	}

	valbool = (val != 0);

	if (ip6_mroute_opt(optname))
		return ip6_mroute_setsockopt(sk, optname, optval, optlen);

	if (needs_rtnl)
		rtnl_lock();
	lock_sock(sk);

	switch (optname) {

	case IPV6_ADDRFORM:
		if (optlen < sizeof(int))
			goto e_inval;
		if (val == PF_INET) {
			struct ipv6_txoptions *opt;
			struct sk_buff *pktopt;

			if (sk->sk_type == SOCK_RAW)
				break;

			if (sk->sk_protocol == IPPROTO_UDP ||
			    sk->sk_protocol == IPPROTO_UDPLITE) {
				struct udp_sock *up = udp_sk(sk);
				if (up->pending == AF_INET6) {
					retv = -EBUSY;
					break;
				}
			} else if (sk->sk_protocol == IPPROTO_TCP) {
				if (sk->sk_prot != &tcpv6_prot) {
					retv = -EBUSY;
					break;
				}
			} else {
				break;
			}

			if (sk->sk_state != TCP_ESTABLISHED) {
				retv = -ENOTCONN;
				break;
			}

			if (ipv6_only_sock(sk) ||
			    !ipv6_addr_v4mapped(&sk->sk_v6_daddr)) {
				retv = -EADDRNOTAVAIL;
				break;
			}

			fl6_free_socklist(sk);
			__ipv6_sock_mc_close(sk);

			/*
			 * Sock is moving from IPv6 to IPv4 (sk_prot), so
			 * remove it from the refcnt debug socks count in the
			 * original family...
			 */
			sk_refcnt_debug_dec(sk);

			if (sk->sk_protocol == IPPROTO_TCP) {
				struct inet_connection_sock *icsk = inet_csk(sk);
				local_bh_disable();
				sock_prot_inuse_add(net, sk->sk_prot, -1);
				sock_prot_inuse_add(net, &tcp_prot, 1);
				local_bh_enable();
				sk->sk_prot = &tcp_prot;
				icsk->icsk_af_ops = &ipv4_specific;
				sk->sk_socket->ops = &inet_stream_ops;
				sk->sk_family = PF_INET;
				tcp_sync_mss(sk, icsk->icsk_pmtu_cookie);
			} else {
				struct proto *prot = &udp_prot;

				if (sk->sk_protocol == IPPROTO_UDPLITE)
					prot = &udplite_prot;
				local_bh_disable();
				sock_prot_inuse_add(net, sk->sk_prot, -1);
				sock_prot_inuse_add(net, prot, 1);
				local_bh_enable();
				sk->sk_prot = prot;
				sk->sk_socket->ops =