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/* $OpenBSD: ip_esp.c,v 1.21 1999/04/11 19:41:37 niklas Exp $ */
/*
* The authors of this code are John Ioannidis (ji@tla.org),
* Angelos D. Keromytis (kermit@csd.uch.gr) and
* Niels Provos (provos@physnet.uni-hamburg.de).
*
* This code was written by John Ioannidis for BSD/OS in Athens, Greece,
* in November 1995.
*
* Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
* by Angelos D. Keromytis.
*
* Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis
* and Niels Provos.
*
* Additional features in 1999 by Angelos D. Keromytis.
*
* Copyright (C) 1995, 1996, 1997, 1998, 1999 by John Ioannidis,
* Angelos D. Keromytis and Niels Provos.
*
* Permission to use, copy, and modify this software without fee
* is hereby granted, provided that this entire notice is included in
* all copies of any software which is or includes a copy or
* modification of this software.
* You may use this code under the GNU public license if you so wish. Please
* contribute changes back to the authors under this freer than GPL license
* so that we may further the use of strong encryption without limitations to
* all.
*
* THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
* REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
* MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
* PURPOSE.
*/
/*
* Encapsulation Security Payload Processing
* Per RFC1827 (Atkinson, 1995)
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/domain.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <sys/errno.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <machine/cpu.h>
#include <net/if.h>
#include <net/route.h>
#include <net/netisr.h>
#include <net/bpf.h>
#include <net/if_enc.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/in_pcb.h>
#include <netinet/in_var.h>
#include <netinet/ip_var.h>
#include <sys/socketvar.h>
#include <net/raw_cb.h>
#include <netinet/ip_icmp.h>
#include <netinet/ip_ipsp.h>
#include <netinet/ip_esp.h>
#include "bpfilter.h"
extern struct ifnet enc_softc;
#ifdef ENCDEBUG
#define DPRINTF(x) if (encdebug) printf x
#else
#define DPRINTF(x)
#endif
int esp_enable = 0;
/*
* esp_input gets called when we receive an packet with an ESP.
*/
void
#if __STDC__
esp_input(struct mbuf *m, ...)
#else
esp_input(m, va_alist)
register struct mbuf *m;
#endif
{
int iphlen;
union sockaddr_union sunion;
struct ifqueue *ifq = NULL;
struct expiration *exp;
struct ip *ipo, ipn;
struct tdb *tdbp;
u_int32_t spi;
int s;
va_list ap;
va_start(ap, m);
iphlen = va_arg(ap, int);
va_end(ap);
espstat.esps_input++;
if (!esp_enable)
{
m_freem(m);
espstat.esps_pdrops++;
return;
}
/*
* Make sure that at least the SPI is in the same mbuf
*/
ipo = mtod(m, struct ip *);
if (m->m_len < iphlen + sizeof(u_int32_t))
{
if ((m = m_pullup(m, iphlen + sizeof(u_int32_t))) == 0)
{
espstat.esps_hdrops++;
return;
}
ipo = mtod(m, struct ip *);
}
spi = *((u_int32_t *) ((caddr_t) ipo + iphlen));
/*
* Find tunnel control block and (indirectly) call the appropriate
* kernel crypto routine. The resulting mbuf chain is a valid
* IP packet ready to go through input processing.
*/
bzero(&sunion, sizeof(sunion));
sunion.sin.sin_family = AF_INET;
sunion.sin.sin_len = sizeof(struct sockaddr_in);
sunion.sin.sin_addr = ipo->ip_dst;
tdbp = gettdb(spi, &sunion, IPPROTO_ESP);
if (tdbp == NULL)
{
DPRINTF(("esp_input(): could not find SA for packet from %s to %s, spi %08x\n", inet_ntoa4(ipo->ip_src), ipsp_address(sunion), ntohl(spi)));
m_freem(m);
espstat.esps_notdb++;
return;
}
if (tdbp->tdb_flags & TDBF_INVALID)
{
DPRINTF(("esp_input(): attempted to use invalid SA %08x, packet from %s to %s\n", ntohl(spi), inet_ntoa4(ipo->ip_src), ipsp_address(sunion)));
m_freem(m);
espstat.esps_invalid++;
return;
}
if (tdbp->tdb_xform == NULL)
{
DPRINTF(("esp_input(): attempted to use uninitialized SA %08x, packet from %s to %s\n", ntohl(spi), inet_ntoa4(ipo->ip_src), ipsp_address(sunion)));
m_freem(m);
espstat.esps_noxform++;
return;
}
m->m_pkthdr.rcvif = &enc_softc;
/* Register first use, setup expiration timer */
if (tdbp->tdb_first_use == 0)
{
tdbp->tdb_first_use = time.tv_sec;
if (tdbp->tdb_flags & TDBF_FIRSTUSE)
{
exp = get_expiration();
bcopy(&tdbp->tdb_dst, &exp->exp_dst, SA_LEN(&tdbp->tdb_dst.sa));
exp->exp_spi = tdbp->tdb_spi;
exp->exp_sproto = tdbp->tdb_sproto;
exp->exp_timeout = tdbp->tdb_first_use + tdbp->tdb_exp_first_use;
put_expiration(exp);
}
if ((tdbp->tdb_flags & TDBF_SOFT_FIRSTUSE) &&
(tdbp->tdb_soft_first_use <= tdbp->tdb_exp_first_use))
{
exp = get_expiration();
bcopy(&tdbp->tdb_dst, &exp->exp_dst, SA_LEN(&tdbp->tdb_dst.sa));
exp->exp_spi = tdbp->tdb_spi;
exp->exp_sproto = tdbp->tdb_sproto;
exp->exp_timeout = tdbp->tdb_first_use + tdbp->tdb_soft_first_use;
put_expiration(exp);
}
}
ipn = *ipo;
m = (*(tdbp->tdb_xform->xf_input))(m, tdbp);
if (m == NULL)
{
DPRINTF(("esp_input(): processing failed for ESP packet from %s to %s, spi %08x\n", inet_ntoa4(ipn.ip_src), ipsp_address(sunion), ntohl(spi)));
espstat.esps_badkcr++;
return;
}
ipo = mtod(m, struct ip *);
if (ipo->ip_p == IPPROTO_IPIP) /* IP-in-IP encapsulation */
{
/* ipn will now contain the inner IP header */
m_copydata(m, ipo->ip_hl << 2, sizeof(struct ip), (caddr_t) &ipn);
if (tdbp->tdb_flags & TDBF_UNIQUE)
if ((ipn.ip_src.s_addr != ipo->ip_src.s_addr) ||
(ipn.ip_dst.s_addr != ipo->ip_dst.s_addr))
{
DPRINTF(("esp_input(): ESP-tunnel with different internal addresses %s->%s (%s->%s), SA %s/%08x\n", inet_ntoa4(ipo->ip_src), inet_ntoa4(ipo->ip_dst), inet_ntoa4(ipn.ip_src), ipsp_address(sunion), ipsp_address(tdbp->tdb_dst), ntohl(tdbp->tdb_spi)));
m_freem(m);
espstat.esps_hdrops++;
return;
}
/*
* Check that the inner source address is the same as
* the proxy address, if available.
*/
if ((tdbp->tdb_proxy.sin.sin_addr.s_addr != INADDR_ANY) &&
(ipn.ip_src.s_addr != tdbp->tdb_proxy.sin.sin_addr.s_addr))
{
DPRINTF(("esp_input(): inner source address %s doesn't correspond to expected proxy source %s, SA %s/%08x\n", inet_ntoa4(ipo->ip_src), inet_ntoa4(tdbp->tdb_proxy.sin.sin_addr), inet_ntoa4(tdbp->tdb_dst.sin.sin_addr), ntohl(tdbp->tdb_spi)));
m_free(m);
espstat.esps_hdrops++;
return;
}
}
/*
* Check that the source address is an expected one, if we know what
* it's supposed to be. This avoids source address spoofing.
*/
if ((tdbp->tdb_src.sin.sin_addr.s_addr != INADDR_ANY) &&
(ipo->ip_src.s_addr != tdbp->tdb_src.sin.sin_addr.s_addr))
{
DPRINTF(("esp_input(): source address %s doesn't correspond to expected source %s, SA %s/%08x\n", inet_ntoa4(ipo->ip_src), ipsp_address(tdbp->tdb_src), ipsp_address(tdbp->tdb_dst), ntohl(tdbp->tdb_spi)));
m_free(m);
espstat.esps_hdrops++;
return;
}
if (ipo->ip_p == IPPROTO_TCP || ipo->ip_p == IPPROTO_UDP)
{
struct tdb_ident *tdbi = NULL;
if (tdbp->tdb_bind_out)
{
tdbi = m->m_pkthdr.tdbi;
if (!(m->m_flags & M_PKTHDR))
{
DPRINTF(("esp_input(): mbuf is not a packet header!\n"));
}
MALLOC(tdbi, struct tdb_ident *, sizeof(struct tdb_ident),
M_TEMP, M_NOWAIT);
if (!tdbi)
goto no_mem;
tdbi->spi = tdbp->tdb_bind_out->tdb_spi;
tdbi->dst = tdbp->tdb_bind_out->tdb_dst;
tdbi->proto = tdbp->tdb_bind_out->tdb_sproto;
}
no_mem:
m->m_pkthdr.tdbi = tdbi;
} else
m->m_pkthdr.tdbi = NULL;
/* Packet is confidental */
m->m_flags |= M_CONF;
#if NBPFILTER > 0
if (enc_softc.if_bpf)
{
/*
* We need to prepend the address family as
* a four byte field. Cons up a dummy header
* to pacify bpf. This is safe because bpf
* will only read from the mbuf (i.e., it won't
* try to free it or keep a pointer a to it).
*/
struct mbuf m0;
struct enchdr hdr;
hdr.af = AF_INET;
hdr.spi = tdbp->tdb_spi;
hdr.flags = m->m_flags & (M_AUTH|M_CONF);
m0.m_next = m;
m0.m_len = ENC_HDRLEN;
m0.m_data = (char *) &hdr;
bpf_mtap(enc_softc.if_bpf, &m0);
}
#endif
/*
* Interface pointer is already in first mbuf; chop off the
* `outer' header and reschedule.
*/
ifq = &ipintrq;
s = splimp(); /* isn't it already? */
if (IF_QFULL(ifq))
{
IF_DROP(ifq);
if (m->m_pkthdr.tdbi)
free(m->m_pkthdr.tdbi, M_TEMP);
m_freem(m);
espstat.esps_qfull++;
splx(s);
DPRINTF(("esp_input(): dropped packet because of full IP queue\n"));
return;
}
IF_ENQUEUE(ifq, m);
schednetisr(NETISR_IP);
splx(s);
return;
}
int
esp_sysctl(name, namelen, oldp, oldlenp, newp, newlen)
int *name;
u_int namelen;
void *oldp;
size_t *oldlenp;
void *newp;
size_t newlen;
{
/* All sysctl names at this level are terminal. */
if (namelen != 1)
return (ENOTDIR);
switch (name[0]) {
case ESPCTL_ENABLE:
return (sysctl_int(oldp, oldlenp, newp, newlen, &esp_enable));
default:
return (ENOPROTOOPT);
}
/* NOTREACHED */
}
|