freebsd-dev/sys/net/if_me.c
Zhenlei Huang 43f8c763cd if_me: Use dedicated network privilege
Separate if_me privileges from if_gif.

Reviewed by:		kp
Differential Revision:	https://reviews.freebsd.org/D36691
2022-10-15 17:05:36 +02:00

690 lines
17 KiB
C

/*-
* Copyright (c) 2014, 2018 Andrey V. Elsukov <ae@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 ``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 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/systm.h>
#include <sys/jail.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mbuf.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/sx.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>
#include <net/bpf.h>
#include <net/ethernet.h>
#include <net/if.h>
#include <net/if_var.h>
#include <net/if_clone.h>
#include <net/if_types.h>
#include <net/netisr.h>
#include <net/vnet.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#include <netinet/ip_encap.h>
#include <machine/in_cksum.h>
#include <security/mac/mac_framework.h>
#define MEMTU (1500 - sizeof(struct mobhdr))
static const char mename[] = "me";
static MALLOC_DEFINE(M_IFME, mename, "Minimal Encapsulation for IP");
/* Minimal forwarding header RFC 2004 */
struct mobhdr {
uint8_t mob_proto; /* protocol */
uint8_t mob_flags; /* flags */
#define MOB_FLAGS_SP 0x80 /* source present */
uint16_t mob_csum; /* header checksum */
struct in_addr mob_dst; /* original destination address */
struct in_addr mob_src; /* original source addr (optional) */
} __packed;
struct me_softc {
struct ifnet *me_ifp;
u_int me_fibnum;
struct in_addr me_src;
struct in_addr me_dst;
CK_LIST_ENTRY(me_softc) chain;
CK_LIST_ENTRY(me_softc) srchash;
};
CK_LIST_HEAD(me_list, me_softc);
#define ME2IFP(sc) ((sc)->me_ifp)
#define ME_READY(sc) ((sc)->me_src.s_addr != 0)
#define ME_RLOCK_TRACKER struct epoch_tracker me_et
#define ME_RLOCK() epoch_enter_preempt(net_epoch_preempt, &me_et)
#define ME_RUNLOCK() epoch_exit_preempt(net_epoch_preempt, &me_et)
#define ME_WAIT() epoch_wait_preempt(net_epoch_preempt)
#ifndef ME_HASH_SIZE
#define ME_HASH_SIZE (1 << 4)
#endif
VNET_DEFINE_STATIC(struct me_list *, me_hashtbl) = NULL;
VNET_DEFINE_STATIC(struct me_list *, me_srchashtbl) = NULL;
#define V_me_hashtbl VNET(me_hashtbl)
#define V_me_srchashtbl VNET(me_srchashtbl)
#define ME_HASH(src, dst) (V_me_hashtbl[\
me_hashval((src), (dst)) & (ME_HASH_SIZE - 1)])
#define ME_SRCHASH(src) (V_me_srchashtbl[\
fnv_32_buf(&(src), sizeof(src), FNV1_32_INIT) & (ME_HASH_SIZE - 1)])
static struct sx me_ioctl_sx;
SX_SYSINIT(me_ioctl_sx, &me_ioctl_sx, "me_ioctl");
static int me_clone_create(struct if_clone *, int, caddr_t);
static void me_clone_destroy(struct ifnet *);
VNET_DEFINE_STATIC(struct if_clone *, me_cloner);
#define V_me_cloner VNET(me_cloner)
#ifdef VIMAGE
static void me_reassign(struct ifnet *, struct vnet *, char *);
#endif
static void me_qflush(struct ifnet *);
static int me_transmit(struct ifnet *, struct mbuf *);
static int me_ioctl(struct ifnet *, u_long, caddr_t);
static int me_output(struct ifnet *, struct mbuf *,
const struct sockaddr *, struct route *);
static int me_input(struct mbuf *, int, int, void *);
static int me_set_tunnel(struct me_softc *, in_addr_t, in_addr_t);
static void me_delete_tunnel(struct me_softc *);
SYSCTL_DECL(_net_link);
static SYSCTL_NODE(_net_link, IFT_TUNNEL, me, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
"Minimal Encapsulation for IP (RFC 2004)");
#ifndef MAX_ME_NEST
#define MAX_ME_NEST 1
#endif
VNET_DEFINE_STATIC(int, max_me_nesting) = MAX_ME_NEST;
#define V_max_me_nesting VNET(max_me_nesting)
SYSCTL_INT(_net_link_me, OID_AUTO, max_nesting, CTLFLAG_RW | CTLFLAG_VNET,
&VNET_NAME(max_me_nesting), 0, "Max nested tunnels");
static uint32_t
me_hashval(in_addr_t src, in_addr_t dst)
{
uint32_t ret;
ret = fnv_32_buf(&src, sizeof(src), FNV1_32_INIT);
return (fnv_32_buf(&dst, sizeof(dst), ret));
}
static struct me_list *
me_hashinit(void)
{
struct me_list *hash;
int i;
hash = malloc(sizeof(struct me_list) * ME_HASH_SIZE,
M_IFME, M_WAITOK);
for (i = 0; i < ME_HASH_SIZE; i++)
CK_LIST_INIT(&hash[i]);
return (hash);
}
static void
vnet_me_init(const void *unused __unused)
{
V_me_cloner = if_clone_simple(mename, me_clone_create,
me_clone_destroy, 0);
}
VNET_SYSINIT(vnet_me_init, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
vnet_me_init, NULL);
static void
vnet_me_uninit(const void *unused __unused)
{
if (V_me_hashtbl != NULL) {
free(V_me_hashtbl, M_IFME);
V_me_hashtbl = NULL;
ME_WAIT();
free(V_me_srchashtbl, M_IFME);
}
if_clone_detach(V_me_cloner);
}
VNET_SYSUNINIT(vnet_me_uninit, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
vnet_me_uninit, NULL);
static int
me_clone_create(struct if_clone *ifc, int unit, caddr_t params)
{
struct me_softc *sc;
sc = malloc(sizeof(struct me_softc), M_IFME, M_WAITOK | M_ZERO);
sc->me_fibnum = curthread->td_proc->p_fibnum;
ME2IFP(sc) = if_alloc(IFT_TUNNEL);
ME2IFP(sc)->if_softc = sc;
if_initname(ME2IFP(sc), mename, unit);
ME2IFP(sc)->if_mtu = MEMTU;
ME2IFP(sc)->if_flags = IFF_POINTOPOINT|IFF_MULTICAST;
ME2IFP(sc)->if_output = me_output;
ME2IFP(sc)->if_ioctl = me_ioctl;
ME2IFP(sc)->if_transmit = me_transmit;
ME2IFP(sc)->if_qflush = me_qflush;
#ifdef VIMAGE
ME2IFP(sc)->if_reassign = me_reassign;
#endif
ME2IFP(sc)->if_capabilities |= IFCAP_LINKSTATE;
ME2IFP(sc)->if_capenable |= IFCAP_LINKSTATE;
if_attach(ME2IFP(sc));
bpfattach(ME2IFP(sc), DLT_NULL, sizeof(u_int32_t));
return (0);
}
#ifdef VIMAGE
static void
me_reassign(struct ifnet *ifp, struct vnet *new_vnet __unused,
char *unused __unused)
{
struct me_softc *sc;
sx_xlock(&me_ioctl_sx);
sc = ifp->if_softc;
if (sc != NULL)
me_delete_tunnel(sc);
sx_xunlock(&me_ioctl_sx);
}
#endif /* VIMAGE */
static void
me_clone_destroy(struct ifnet *ifp)
{
struct me_softc *sc;
sx_xlock(&me_ioctl_sx);
sc = ifp->if_softc;
me_delete_tunnel(sc);
bpfdetach(ifp);
if_detach(ifp);
ifp->if_softc = NULL;
sx_xunlock(&me_ioctl_sx);
ME_WAIT();
if_free(ifp);
free(sc, M_IFME);
}
static int
me_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
{
struct ifreq *ifr = (struct ifreq *)data;
struct sockaddr_in *src, *dst;
struct me_softc *sc;
int error;
switch (cmd) {
case SIOCSIFMTU:
if (ifr->ifr_mtu < 576)
return (EINVAL);
ifp->if_mtu = ifr->ifr_mtu;
return (0);
case SIOCSIFADDR:
ifp->if_flags |= IFF_UP;
case SIOCSIFFLAGS:
case SIOCADDMULTI:
case SIOCDELMULTI:
return (0);
}
sx_xlock(&me_ioctl_sx);
sc = ifp->if_softc;
if (sc == NULL) {
error = ENXIO;
goto end;
}
error = 0;
switch (cmd) {
case SIOCSIFPHYADDR:
src = &((struct in_aliasreq *)data)->ifra_addr;
dst = &((struct in_aliasreq *)data)->ifra_dstaddr;
if (src->sin_family != dst->sin_family ||
src->sin_family != AF_INET ||
src->sin_len != dst->sin_len ||
src->sin_len != sizeof(struct sockaddr_in)) {
error = EINVAL;
break;
}
if (src->sin_addr.s_addr == INADDR_ANY ||
dst->sin_addr.s_addr == INADDR_ANY) {
error = EADDRNOTAVAIL;
break;
}
error = me_set_tunnel(sc, src->sin_addr.s_addr,
dst->sin_addr.s_addr);
break;
case SIOCDIFPHYADDR:
me_delete_tunnel(sc);
break;
case SIOCGIFPSRCADDR:
case SIOCGIFPDSTADDR:
if (!ME_READY(sc)) {
error = EADDRNOTAVAIL;
break;
}
src = (struct sockaddr_in *)&ifr->ifr_addr;
memset(src, 0, sizeof(*src));
src->sin_family = AF_INET;
src->sin_len = sizeof(*src);
switch (cmd) {
case SIOCGIFPSRCADDR:
src->sin_addr = sc->me_src;
break;
case SIOCGIFPDSTADDR:
src->sin_addr = sc->me_dst;
break;
}
error = prison_if(curthread->td_ucred, sintosa(src));
if (error != 0)
memset(src, 0, sizeof(*src));
break;
case SIOCGTUNFIB:
ifr->ifr_fib = sc->me_fibnum;
break;
case SIOCSTUNFIB:
if ((error = priv_check(curthread, PRIV_NET_ME)) != 0)
break;
if (ifr->ifr_fib >= rt_numfibs)
error = EINVAL;
else
sc->me_fibnum = ifr->ifr_fib;
break;
default:
error = EINVAL;
break;
}
end:
sx_xunlock(&me_ioctl_sx);
return (error);
}
static int
me_lookup(const struct mbuf *m, int off, int proto, void **arg)
{
const struct ip *ip;
struct me_softc *sc;
if (V_me_hashtbl == NULL)
return (0);
NET_EPOCH_ASSERT();
ip = mtod(m, const struct ip *);
CK_LIST_FOREACH(sc, &ME_HASH(ip->ip_dst.s_addr,
ip->ip_src.s_addr), chain) {
if (sc->me_src.s_addr == ip->ip_dst.s_addr &&
sc->me_dst.s_addr == ip->ip_src.s_addr) {
if ((ME2IFP(sc)->if_flags & IFF_UP) == 0)
return (0);
*arg = sc;
return (ENCAP_DRV_LOOKUP);
}
}
return (0);
}
/*
* Check that ingress address belongs to local host.
*/
static void
me_set_running(struct me_softc *sc)
{
if (in_localip(sc->me_src))
ME2IFP(sc)->if_drv_flags |= IFF_DRV_RUNNING;
else
ME2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING;
}
/*
* ifaddr_event handler.
* Clear IFF_DRV_RUNNING flag when ingress address disappears to prevent
* source address spoofing.
*/
static void
me_srcaddr(void *arg __unused, const struct sockaddr *sa,
int event __unused)
{
const struct sockaddr_in *sin;
struct me_softc *sc;
/* Check that VNET is ready */
if (V_me_hashtbl == NULL)
return;
NET_EPOCH_ASSERT();
sin = (const struct sockaddr_in *)sa;
CK_LIST_FOREACH(sc, &ME_SRCHASH(sin->sin_addr.s_addr), srchash) {
if (sc->me_src.s_addr != sin->sin_addr.s_addr)
continue;
me_set_running(sc);
}
}
static int
me_set_tunnel(struct me_softc *sc, in_addr_t src, in_addr_t dst)
{
struct epoch_tracker et;
struct me_softc *tmp;
sx_assert(&me_ioctl_sx, SA_XLOCKED);
if (V_me_hashtbl == NULL) {
V_me_hashtbl = me_hashinit();
V_me_srchashtbl = me_hashinit();
}
if (sc->me_src.s_addr == src && sc->me_dst.s_addr == dst)
return (0);
CK_LIST_FOREACH(tmp, &ME_HASH(src, dst), chain) {
if (tmp == sc)
continue;
if (tmp->me_src.s_addr == src &&
tmp->me_dst.s_addr == dst)
return (EADDRNOTAVAIL);
}
me_delete_tunnel(sc);
sc->me_dst.s_addr = dst;
sc->me_src.s_addr = src;
CK_LIST_INSERT_HEAD(&ME_HASH(src, dst), sc, chain);
CK_LIST_INSERT_HEAD(&ME_SRCHASH(src), sc, srchash);
NET_EPOCH_ENTER(et);
me_set_running(sc);
NET_EPOCH_EXIT(et);
if_link_state_change(ME2IFP(sc), LINK_STATE_UP);
return (0);
}
static void
me_delete_tunnel(struct me_softc *sc)
{
sx_assert(&me_ioctl_sx, SA_XLOCKED);
if (ME_READY(sc)) {
CK_LIST_REMOVE(sc, chain);
CK_LIST_REMOVE(sc, srchash);
ME_WAIT();
sc->me_src.s_addr = 0;
sc->me_dst.s_addr = 0;
ME2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING;
if_link_state_change(ME2IFP(sc), LINK_STATE_DOWN);
}
}
static uint16_t
me_in_cksum(uint16_t *p, int nwords)
{
uint32_t sum = 0;
while (nwords-- > 0)
sum += *p++;
sum = (sum >> 16) + (sum & 0xffff);
sum += (sum >> 16);
return (~sum);
}
static int
me_input(struct mbuf *m, int off, int proto, void *arg)
{
struct me_softc *sc = arg;
struct mobhdr *mh;
struct ifnet *ifp;
struct ip *ip;
int hlen;
NET_EPOCH_ASSERT();
ifp = ME2IFP(sc);
/* checks for short packets */
hlen = sizeof(struct mobhdr);
if (m->m_pkthdr.len < sizeof(struct ip) + hlen)
hlen -= sizeof(struct in_addr);
if (m->m_len < sizeof(struct ip) + hlen)
m = m_pullup(m, sizeof(struct ip) + hlen);
if (m == NULL)
goto drop;
mh = (struct mobhdr *)mtodo(m, sizeof(struct ip));
/* check for wrong flags */
if (mh->mob_flags & (~MOB_FLAGS_SP)) {
m_freem(m);
goto drop;
}
if (mh->mob_flags) {
if (hlen != sizeof(struct mobhdr)) {
m_freem(m);
goto drop;
}
} else
hlen = sizeof(struct mobhdr) - sizeof(struct in_addr);
/* check mobile header checksum */
if (me_in_cksum((uint16_t *)mh, hlen / sizeof(uint16_t)) != 0) {
m_freem(m);
goto drop;
}
#ifdef MAC
mac_ifnet_create_mbuf(ifp, m);
#endif
ip = mtod(m, struct ip *);
ip->ip_dst = mh->mob_dst;
ip->ip_p = mh->mob_proto;
ip->ip_sum = 0;
ip->ip_len = htons(m->m_pkthdr.len - hlen);
if (mh->mob_flags)
ip->ip_src = mh->mob_src;
memmove(mtodo(m, hlen), ip, sizeof(struct ip));
m_adj(m, hlen);
m_clrprotoflags(m);
m->m_pkthdr.rcvif = ifp;
m->m_pkthdr.csum_flags |= (CSUM_IP_CHECKED | CSUM_IP_VALID);
M_SETFIB(m, ifp->if_fib);
hlen = AF_INET;
BPF_MTAP2(ifp, &hlen, sizeof(hlen), m);
if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
if_inc_counter(ifp, IFCOUNTER_IBYTES, m->m_pkthdr.len);
if ((ifp->if_flags & IFF_MONITOR) != 0)
m_freem(m);
else
netisr_dispatch(NETISR_IP, m);
return (IPPROTO_DONE);
drop:
if_inc_counter(ifp, IFCOUNTER_IERRORS, 1);
return (IPPROTO_DONE);
}
static int
me_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
struct route *ro)
{
uint32_t af;
if (dst->sa_family == AF_UNSPEC)
bcopy(dst->sa_data, &af, sizeof(af));
else
af = RO_GET_FAMILY(ro, dst);
m->m_pkthdr.csum_data = af;
return (ifp->if_transmit(ifp, m));
}
#define MTAG_ME 1414491977
static int
me_transmit(struct ifnet *ifp, struct mbuf *m)
{
ME_RLOCK_TRACKER;
struct mobhdr mh;
struct me_softc *sc;
struct ip *ip;
uint32_t af;
int error, hlen, plen;
ME_RLOCK();
#ifdef MAC
error = mac_ifnet_check_transmit(ifp, m);
if (error != 0)
goto drop;
#endif
error = ENETDOWN;
sc = ifp->if_softc;
if (sc == NULL || !ME_READY(sc) ||
(ifp->if_flags & IFF_MONITOR) != 0 ||
(ifp->if_flags & IFF_UP) == 0 ||
(ifp->if_drv_flags & IFF_DRV_RUNNING) == 0 ||
(error = if_tunnel_check_nesting(ifp, m, MTAG_ME,
V_max_me_nesting)) != 0) {
m_freem(m);
goto drop;
}
af = m->m_pkthdr.csum_data;
if (af != AF_INET) {
error = EAFNOSUPPORT;
m_freem(m);
goto drop;
}
if (m->m_len < sizeof(struct ip))
m = m_pullup(m, sizeof(struct ip));
if (m == NULL) {
error = ENOBUFS;
goto drop;
}
ip = mtod(m, struct ip *);
/* Fragmented datagramms shouldn't be encapsulated */
if (ip->ip_off & htons(IP_MF | IP_OFFMASK)) {
error = EINVAL;
m_freem(m);
goto drop;
}
mh.mob_proto = ip->ip_p;
mh.mob_src = ip->ip_src;
mh.mob_dst = ip->ip_dst;
if (in_hosteq(sc->me_src, ip->ip_src)) {
hlen = sizeof(struct mobhdr) - sizeof(struct in_addr);
mh.mob_flags = 0;
} else {
hlen = sizeof(struct mobhdr);
mh.mob_flags = MOB_FLAGS_SP;
}
BPF_MTAP2(ifp, &af, sizeof(af), m);
plen = m->m_pkthdr.len;
ip->ip_src = sc->me_src;
ip->ip_dst = sc->me_dst;
m->m_flags &= ~(M_BCAST|M_MCAST);
M_SETFIB(m, sc->me_fibnum);
M_PREPEND(m, hlen, M_NOWAIT);
if (m == NULL) {
error = ENOBUFS;
goto drop;
}
if (m->m_len < sizeof(struct ip) + hlen)
m = m_pullup(m, sizeof(struct ip) + hlen);
if (m == NULL) {
error = ENOBUFS;
goto drop;
}
memmove(mtod(m, void *), mtodo(m, hlen), sizeof(struct ip));
ip = mtod(m, struct ip *);
ip->ip_len = htons(m->m_pkthdr.len);
ip->ip_p = IPPROTO_MOBILE;
ip->ip_sum = 0;
mh.mob_csum = 0;
mh.mob_csum = me_in_cksum((uint16_t *)&mh, hlen / sizeof(uint16_t));
bcopy(&mh, mtodo(m, sizeof(struct ip)), hlen);
error = ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL);
drop:
if (error)
if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
else {
if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
if_inc_counter(ifp, IFCOUNTER_OBYTES, plen);
}
ME_RUNLOCK();
return (error);
}
static void
me_qflush(struct ifnet *ifp __unused)
{
}
static const struct srcaddrtab *me_srcaddrtab = NULL;
static const struct encaptab *ecookie = NULL;
static const struct encap_config me_encap_cfg = {
.proto = IPPROTO_MOBILE,
.min_length = sizeof(struct ip) + sizeof(struct mobhdr) -
sizeof(in_addr_t),
.exact_match = ENCAP_DRV_LOOKUP,
.lookup = me_lookup,
.input = me_input
};
static int
memodevent(module_t mod, int type, void *data)
{
switch (type) {
case MOD_LOAD:
me_srcaddrtab = ip_encap_register_srcaddr(me_srcaddr,
NULL, M_WAITOK);
ecookie = ip_encap_attach(&me_encap_cfg, NULL, M_WAITOK);
break;
case MOD_UNLOAD:
ip_encap_detach(ecookie);
ip_encap_unregister_srcaddr(me_srcaddrtab);
break;
default:
return (EOPNOTSUPP);
}
return (0);
}
static moduledata_t me_mod = {
"if_me",
memodevent,
0
};
DECLARE_MODULE(if_me, me_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
MODULE_VERSION(if_me, 1);