freebsd-dev/sys/netinet6/send.c
Roy Marples 7045b1603b socket: Implement SO_RERROR
SO_RERROR indicates that receive buffer overflows should be handled as
errors. Historically receive buffer overflows have been ignored and
programs could not tell if they missed messages or messages had been
truncated because of overflows. Since programs historically do not
expect to get receive overflow errors, this behavior is not the
default.

This is really really important for programs that use route(4) to keep
in sync with the system. If we loose a message then we need to reload
the full system state, otherwise the behaviour from that point is
undefined and can lead to chasing bogus bug reports.

Reviewed by:	philip (network), kbowling (transport), gbe (manpages)
MFC after:	2 weeks
Differential Revision:	https://reviews.freebsd.org/D26652
2021-07-28 09:35:09 -07:00

393 lines
9.3 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2009-2010 Ana Kukec <anchie@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/module.h>
#include <sys/priv.h>
#include <sys/protosw.h>
#include <sys/sdt.h>
#include <sys/systm.h>
#include <sys/socket.h>
#include <sys/sockbuf.h>
#include <sys/socketvar.h>
#include <sys/types.h>
#include <net/route.h>
#include <net/if.h>
#include <net/if_var.h>
#include <net/vnet.h>
#include <netinet/in.h>
#include <netinet/in_kdtrace.h>
#include <netinet/ip_var.h>
#include <netinet/ip6.h>
#include <netinet/icmp6.h>
#include <netinet6/in6_var.h>
#include <netinet6/nd6.h>
#include <netinet6/scope6_var.h>
#include <netinet6/send.h>
static MALLOC_DEFINE(M_SEND, "send", "Secure Neighbour Discovery");
/*
* The socket used to communicate with the SeND daemon.
*/
VNET_DEFINE_STATIC(struct socket *, send_so);
#define V_send_so VNET(send_so)
u_long send_sendspace = 8 * (1024 + sizeof(struct sockaddr_send));
u_long send_recvspace = 9216;
struct mtx send_mtx;
#define SEND_LOCK_INIT() mtx_init(&send_mtx, "send_mtx", NULL, MTX_DEF)
#define SEND_LOCK() mtx_lock(&send_mtx)
#define SEND_UNLOCK() mtx_unlock(&send_mtx)
#define SEND_LOCK_DESTROY() mtx_destroy(&send_mtx)
static int
send_attach(struct socket *so, int proto, struct thread *td)
{
int error;
SEND_LOCK();
if (V_send_so != NULL) {
SEND_UNLOCK();
return (EEXIST);
}
error = priv_check(td, PRIV_NETINET_RAW);
if (error) {
SEND_UNLOCK();
return(error);
}
if (proto != IPPROTO_SEND) {
SEND_UNLOCK();
return (EPROTONOSUPPORT);
}
error = soreserve(so, send_sendspace, send_recvspace);
if (error) {
SEND_UNLOCK();
return(error);
}
V_send_so = so;
SEND_UNLOCK();
return (0);
}
static int
send_output(struct mbuf *m, struct ifnet *ifp, int direction)
{
struct ip6_hdr *ip6;
struct sockaddr_in6 dst;
struct icmp6_hdr *icmp6;
struct epoch_tracker et;
int icmp6len;
int error;
/*
* Receive incoming (SeND-protected) or outgoing traffic
* (SeND-validated) from the SeND user space application.
*/
switch (direction) {
case SND_IN:
if (m->m_len < (sizeof(struct ip6_hdr) +
sizeof(struct icmp6_hdr))) {
m = m_pullup(m, sizeof(struct ip6_hdr) +
sizeof(struct icmp6_hdr));
if (!m)
return (ENOBUFS);
}
/* Before passing off the mbuf record the proper interface. */
m->m_pkthdr.rcvif = ifp;
if (m->m_flags & M_PKTHDR)
icmp6len = m->m_pkthdr.len - sizeof(struct ip6_hdr);
else
panic("Doh! not the first mbuf.");
ip6 = mtod(m, struct ip6_hdr *);
icmp6 = (struct icmp6_hdr *)(ip6 + 1);
error = 0;
/*
* Output the packet as icmp6.c:icpm6_input() would do.
* The mbuf is always consumed, so we do not have to
* care about that.
*/
NET_EPOCH_ENTER(et);
switch (icmp6->icmp6_type) {
case ND_NEIGHBOR_SOLICIT:
nd6_ns_input(m, sizeof(struct ip6_hdr), icmp6len);
break;
case ND_NEIGHBOR_ADVERT:
nd6_na_input(m, sizeof(struct ip6_hdr), icmp6len);
break;
case ND_REDIRECT:
icmp6_redirect_input(m, sizeof(struct ip6_hdr));
break;
case ND_ROUTER_SOLICIT:
nd6_rs_input(m, sizeof(struct ip6_hdr), icmp6len);
break;
case ND_ROUTER_ADVERT:
nd6_ra_input(m, sizeof(struct ip6_hdr), icmp6len);
break;
default:
m_freem(m);
error = ENOSYS;
}
NET_EPOCH_EXIT(et);
return (error);
case SND_OUT:
if (m->m_len < sizeof(struct ip6_hdr)) {
m = m_pullup(m, sizeof(struct ip6_hdr));
if (!m)
return (ENOBUFS);
}
ip6 = mtod(m, struct ip6_hdr *);
if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst))
m->m_flags |= M_MCAST;
bzero(&dst, sizeof(dst));
dst.sin6_family = AF_INET6;
dst.sin6_len = sizeof(dst);
dst.sin6_addr = ip6->ip6_dst;
m_clrprotoflags(m); /* Avoid confusing lower layers. */
IP_PROBE(send, NULL, NULL, ip6, ifp, NULL, ip6);
/*
* Output the packet as nd6.c:nd6_output_lle() would do.
* The mbuf is always consumed, so we do not have to care
* about that.
* XXX-BZ as we added data, what about fragmenting,
* if now needed?
*/
error = ((*ifp->if_output)(ifp, m, (struct sockaddr *)&dst,
NULL));
if (error)
error = ENOENT;
return (error);
default:
panic("%s: direction %d neither SND_IN nor SND_OUT.",
__func__, direction);
}
}
/*
* Receive a SeND message from user space to be either send out by the kernel
* or, with SeND ICMPv6 options removed, to be further processed by the icmp6
* input path.
*/
static int
send_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam,
struct mbuf *control, struct thread *td)
{
struct sockaddr_send *sendsrc;
struct ifnet *ifp;
int error;
KASSERT(V_send_so == so, ("%s: socket %p not send socket %p",
__func__, so, V_send_so));
sendsrc = (struct sockaddr_send *)nam;
if (sendsrc->send_family != AF_INET6) {
error = EAFNOSUPPORT;
goto err;
}
if (sendsrc->send_len != sizeof(*sendsrc)) {
error = EINVAL;
goto err;
}
ifp = ifnet_byindex_ref(sendsrc->send_ifidx);
if (ifp == NULL) {
error = ENETUNREACH;
goto err;
}
error = send_output(m, ifp, sendsrc->send_direction);
if_rele(ifp);
m = NULL;
err:
if (control != NULL)
m_freem(control);
if (m != NULL)
m_freem(m);
return (error);
}
static void
send_close(struct socket *so)
{
SEND_LOCK();
if (V_send_so)
V_send_so = NULL;
SEND_UNLOCK();
}
/*
* Send a SeND message to user space, that was either received and has to be
* validated or was about to be send out and has to be handled by the SEND
* daemon adding SeND ICMPv6 options.
*/
static int
send_input(struct mbuf *m, struct ifnet *ifp, int direction, int msglen __unused)
{
struct ip6_hdr *ip6;
struct sockaddr_send sendsrc;
SEND_LOCK();
if (V_send_so == NULL) {
SEND_UNLOCK();
return (-1);
}
/*
* Make sure to clear any possible internally embedded scope before
* passing the packet to user space for SeND cryptographic signature
* validation to succeed.
*/
ip6 = mtod(m, struct ip6_hdr *);
in6_clearscope(&ip6->ip6_src);
in6_clearscope(&ip6->ip6_dst);
bzero(&sendsrc, sizeof(sendsrc));
sendsrc.send_len = sizeof(sendsrc);
sendsrc.send_family = AF_INET6;
sendsrc.send_direction = direction;
sendsrc.send_ifidx = ifp->if_index;
/*
* Send incoming or outgoing traffic to user space either to be
* protected (outgoing) or validated (incoming) according to rfc3971.
*/
SOCKBUF_LOCK(&V_send_so->so_rcv);
if (sbappendaddr_locked(&V_send_so->so_rcv,
(struct sockaddr *)&sendsrc, m, NULL) == 0) {
soroverflow_locked(V_send_so);
/* XXX stats. */
m_freem(m);
} else {
sorwakeup_locked(V_send_so);
}
SEND_UNLOCK();
return (0);
}
struct pr_usrreqs send_usrreqs = {
.pru_attach = send_attach,
.pru_send = send_send,
.pru_detach = send_close
};
struct protosw send_protosw = {
.pr_type = SOCK_RAW,
.pr_flags = PR_ATOMIC|PR_ADDR,
.pr_protocol = IPPROTO_SEND,
.pr_usrreqs = &send_usrreqs
};
static int
send_modevent(module_t mod, int type, void *unused)
{
#ifdef __notyet__
VNET_ITERATOR_DECL(vnet_iter);
#endif
int error;
switch (type) {
case MOD_LOAD:
SEND_LOCK_INIT();
error = pf_proto_register(PF_INET6, &send_protosw);
if (error != 0) {
printf("%s:%d: MOD_LOAD pf_proto_register(): %d\n",
__func__, __LINE__, error);
SEND_LOCK_DESTROY();
break;
}
send_sendso_input_hook = send_input;
break;
case MOD_UNLOAD:
/* Do not allow unloading w/o locking. */
return (EBUSY);
#ifdef __notyet__
VNET_LIST_RLOCK_NOSLEEP();
SEND_LOCK();
VNET_FOREACH(vnet_iter) {
CURVNET_SET(vnet_iter);
if (V_send_so != NULL) {
CURVNET_RESTORE();
SEND_UNLOCK();
VNET_LIST_RUNLOCK_NOSLEEP();
return (EBUSY);
}
CURVNET_RESTORE();
}
SEND_UNLOCK();
VNET_LIST_RUNLOCK_NOSLEEP();
error = pf_proto_unregister(PF_INET6, IPPROTO_SEND, SOCK_RAW);
if (error == 0)
SEND_LOCK_DESTROY();
send_sendso_input_hook = NULL;
break;
#endif
default:
error = 0;
break;
}
return (error);
}
static moduledata_t sendmod = {
"send",
send_modevent,
0
};
DECLARE_MODULE(send, sendmod, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY);