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);

DEFINE_STATIC_KEY_FALSE(ip6_min_hopcount);

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_test_bit(IS_ICSK, sk)) {
		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 copy_group_source_from_sockptr(struct group_source_req *greqs,
		sockptr_t optval, int optlen)
{
	if (in_compat_syscall()) {
		struct compat_group_source_req gr32;

		if (optlen < sizeof(gr32))
			return -EINVAL;
		if (copy_from_sockptr(&gr32, optval, sizeof(gr32)))
			return -EFAULT;
		greqs->gsr_interface = gr32.gsr_interface;
		greqs->gsr_group = gr32.gsr_group;
		greqs->gsr_source = gr32.gsr_source;
	} else {
		if (optlen < sizeof(*greqs))
			return -EINVAL;
		if (copy_from_sockptr(greqs, optval, sizeof(*greqs)))
			return -EFAULT;
	}

	return 0;
}

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

	ret = copy_group_source_from_sockptr(&greqs, optval, optlen);
	if (ret)
		return ret;

	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 ipv6_set_mcast_msfilter(struct sock *sk, sockptr_t optval,
		int optlen)
{
	struct group_filter *gsf;
	int ret;

	if (optlen < GROUP_FILTER_SIZE(0))
		return -EINVAL;
	if (optlen > READ_ONCE(sysctl_optmem_max))
		return -ENOBUFS;

	gsf = memdup_sockptr(optval, optlen);
	if (IS_ERR(gsf))
		return PTR_ERR(gsf);

	/* numsrc >= (4G-140)/128 overflow in 32 bits */
	ret = -ENOBUFS;
	if (gsf->gf_numsrc >= 0x1ffffffU ||
	    gsf->gf_numsrc > sysctl_mld_max_msf)
		goto out_free_gsf;

	ret = -EINVAL;
	if (GROUP_FILTER_SIZE(gsf->gf_numsrc) > optlen)
		goto out_free_gsf;

	ret = ip6_mc_msfilter(sk, gsf, gsf->gf_slist_flex);
out_free_gsf:
	kfree(gsf);
	return ret;
}

static int compat_ipv6_set_mcast_msfilter(struct sock *sk, sockptr_t optval,
		int optlen)
{
	const int size0 = offsetof(struct compat_group_filter, gf_slist_flex);
	struct compat_group_filter *gf32;
	void *p;
	int ret;
	int n;

	if (optlen < size0)
		return -EINVAL;
	if (optlen > READ_ONCE(sysctl_optmem_max) - 4)
		return -ENOBUFS;

	p = kmalloc(optlen + 4, GFP_KERNEL);
	if (!p)
		return -ENOMEM;

	gf32 = p + 4; /* we want ->gf_group and ->gf_slist_flex aligned */
	ret = -EFAULT;
	if (copy_from_sockptr(gf32, optval, optlen))
		goto out_free_p;

	/* numsrc >= (4G-140)/128 overflow in 32 bits */
	ret = -ENOBUFS;
	n = gf32->gf_numsrc;
	if (n >= 0x1ffffffU || n > sysctl_mld_max_msf)
		goto out_free_p;

	ret = -EINVAL;
	if (offsetof(struct compat_group_filter, gf_slist_flex[n]) > optlen)
		goto out_free_p;

	ret = ip6_mc_msfilter(sk, &(struct group_filter){
			.gf_interface = gf32->gf_interface,
			.gf_group = gf32->gf_group,
			.gf_fmode = gf32->gf_fmode,
			.gf_numsrc = gf32->gf_numsrc}, gf32->gf_slist_flex);

out_free_p:
	kfree(p);
	return ret;
}

static int ipv6_mcast_join_leave(struct sock *sk, int optname,
		sockptr_t optval, int optlen)
{
	struct sockaddr_in6 *psin6;
	struct group_req greq;

	if (optlen < sizeof(greq))
		return -EINVAL;
	if (copy_from_sockptr(&greq, optval, sizeof(greq)))
		return -EFAULT;

	if (greq.gr_group.ss_family != AF_INET6)
		return -EADDRNOTAVAIL;
	psin6 = (struct sockaddr_in6 *)&greq.gr_group;
	if (optname == MCAST_JOIN_GROUP)
		return ipv6_sock_mc_join(sk, greq.gr_interface,
					 &psin6->sin6_addr);
	return ipv6_sock_mc_drop(sk, greq.gr_interface, &psin6->sin6_addr);
}

static int compat_ipv6_mcast_join_leave(struct sock *sk, int optname,
		sockptr_t optval, int optlen)
{
	struct compat_group_req gr32;
	struct sockaddr_in6 *psin6;

	if (optlen < sizeof(gr32))
		return -EINVAL;
	if (copy_from_sockptr(&gr32, optval, sizeof(gr32)))
		return -EFAULT;

	if (gr32.gr_group.ss_family != AF_INET6)
		return -EADDRNOTAVAIL;
	psin6 = (struct sockaddr_in6 *)&gr32.gr_group;
	if (optname == MCAST_JOIN_GROUP)
		return ipv6_sock_mc_join(sk, gr32.gr_interface,
					&psin6->sin6_addr);
	return ipv6_sock_mc_drop(sk, gr32.gr_interface, &psin6->sin6_addr);
}

static int ipv6_set_opt_hdr(struct sock *sk, int optname, sockptr_t optval,
		int optlen)
{
	struct ipv6_pinfo *np = inet6_sk(sk);
	struct ipv6_opt_hdr *new = NULL;
	struct net *net = sock_net(sk);
	struct ipv6_txoptions *opt;
	int err;

	/* hop-by-hop / destinat