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Do not use xform_ipip as decapsulation fallback.

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xform_ipip was used as fallback with low priority for IPIP
encapsulated packets that were decrypted. In some cases
it can decapsulate packets, that it shouldn't. This leads to situations,
when wrong configurations are magically working. Also it can propagate
wrong ingress interface and this can break security.

Now we redesigned the IPSEC code and IPIP encapsulation is called directly
from ipsec_output, and decapsulation is done in the ipsec_input with m_striphdr.

Differential Revision:	https://reviews.freebsd.org/D1220
MFC after:	1 month
Sponsored by:	Yandex LLC
This commit is contained in:
Andrey V. Elsukov 2014-11-26 17:44:49 +00:00
parent 2731e062b5
commit b05765d75f
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=275133
4 changed files with 8 additions and 433 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
ObsoleteFiles.inc
View File

@ -38,6 +38,8 @@
# xargs -n1 | sort | uniq -d;
# done
# 20141126: remove xform_ipip decapsulation fallback
OLD_FILES+=usr/include/netipsec/ipip_var.h
# 20141109: faith/faithd removal
OLD_FILES+=etc/rc.d/faith
OLD_FILES+=usr/share/man/man4/faith.4.gz

71
sys/netipsec/ipip_var.h
View File

@ -1,71 +0,0 @@
/* $FreeBSD$ */
/* $OpenBSD: ip_ipip.h,v 1.5 2002/06/09 16:26:10 itojun 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).
*
* The original version of 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.
* Copyright (c) 2001, Angelos D. Keromytis.
*
* Permission to use, copy, and modify this software with or 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.
*/
#ifndef _NETINET_IPIP_H_
#define _NETINET_IPIP_H_
/*
* IP-inside-IP processing.
* Not quite all the functionality of RFC-1853, but the main idea is there.
*/
struct ipipstat {
uint64_t ipips_ipackets; /* total input packets */
uint64_t ipips_opackets; /* total output packets */
uint64_t ipips_hdrops; /* packet shorter than header shows */
uint64_t ipips_qfull;
uint64_t ipips_ibytes;
uint64_t ipips_obytes;
uint64_t ipips_pdrops; /* packet dropped due to policy */
uint64_t ipips_spoof; /* IP spoofing attempts */
uint64_t ipips_family; /* Protocol family mismatch */
uint64_t ipips_unspec; /* Missing tunnel endpoint address */
};
#ifdef _KERNEL
#include <sys/counter.h>
VNET_DECLARE(int, ipip_allow);
VNET_PCPUSTAT_DECLARE(struct ipipstat, ipipstat);
#define IPIPSTAT_ADD(name, val) \
VNET_PCPUSTAT_ADD(struct ipipstat, ipipstat, name, (val))
#define IPIPSTAT_INC(name) IPIPSTAT_ADD(name, 1)
#define V_ipip_allow VNET(ipip_allow)
#endif /* _KERNEL */
#endif /* _NETINET_IPIP_H_ */

1
sys/netipsec/xform.h
View File

@ -109,7 +109,6 @@ extern int xform_init(struct secasvar *sav, int xftype);
struct cryptoini;
/* XF_IP4 */
extern int ip4_input6(struct mbuf **m, int *offp, int proto);
extern int ip4_input(struct mbuf **, int *, int);
extern int ipip_output(struct mbuf *, struct ipsecrequest *,
struct mbuf **, int, int);

367
sys/netipsec/xform_ipip.c
View File

@ -64,290 +64,24 @@
#include <netinet/ip.h>
#include <netinet/ip_ecn.h>
#include <netinet/ip_var.h>
#include <netinet/ip_encap.h>
#include <netipsec/ipsec.h>
#include <netipsec/xform.h>
#include <netipsec/ipip_var.h>
#ifdef INET6
#include <netinet/ip6.h>
#include <netipsec/ipsec6.h>
#include <netinet6/ip6_ecn.h>
#include <netinet6/in6_var.h>
#include <netinet6/ip6protosw.h>
#include <netinet6/scope6_var.h>
#endif
#include <netipsec/key.h>
#include <netipsec/key_debug.h>
#include <machine/stdarg.h>
/*
* We can control the acceptance of IP4 packets by altering the sysctl
* net.inet.ipip.allow value. Zero means drop them, all else is acceptance.
*/
VNET_DEFINE(int, ipip_allow) = 0;
VNET_PCPUSTAT_DEFINE(struct ipipstat, ipipstat);
VNET_PCPUSTAT_SYSINIT(ipipstat);
#ifdef VIMAGE
VNET_PCPUSTAT_SYSUNINIT(ipipstat);
#endif /* VIMAGE */
SYSCTL_DECL(_net_inet_ipip);
SYSCTL_INT(_net_inet_ipip, OID_AUTO, ipip_allow, CTLFLAG_VNET | CTLFLAG_RW,
&VNET_NAME(ipip_allow), 0, "");
SYSCTL_VNET_PCPUSTAT(_net_inet_ipip, IPSECCTL_STATS, stats,
struct ipipstat, ipipstat,
"IPIP statistics (struct ipipstat, netipsec/ipip_var.h)");
/* XXX IPCOMP */
#define M_IPSEC (M_AUTHIPHDR|M_AUTHIPDGM|M_DECRYPTED)
static void _ipip_input(struct mbuf *m, int iphlen, struct ifnet *gifp);
#ifdef INET6
/*
* Really only a wrapper for ipip_input(), for use with IPv6.
*/
int
ip4_input6(struct mbuf **m, int *offp, int proto)
{
#if 0
/* If we do not accept IP-in-IP explicitly, drop. */
if (!V_ipip_allow && ((*m)->m_flags & M_IPSEC) == 0) {
DPRINTF(("%s: dropped due to policy\n", __func__));
IPIPSTAT_INC(ipips_pdrops);
m_freem(*m);
return IPPROTO_DONE;
}
#endif
_ipip_input(*m, *offp, NULL);
return IPPROTO_DONE;
}
#endif /* INET6 */
#ifdef INET
/*
* Really only a wrapper for ipip_input(), for use with IPv4.
*/
int
ip4_input(struct mbuf **mp, int *offp, int proto)
{
#if 0
/* If we do not accept IP-in-IP explicitly, drop. */
if (!V_ipip_allow && (m->m_flags & M_IPSEC) == 0) {
DPRINTF(("%s: dropped due to policy\n", __func__));
IPIPSTAT_INC(ipips_pdrops);
m_freem(m);
return;
}
#endif
_ipip_input(*mp, *offp, NULL);
return (IPPROTO_DONE);
}
#endif /* INET */
/*
* ipip_input gets called when we receive an IP{46} encapsulated packet,
* either because we got it at a real interface, or because AH or ESP
* were being used in tunnel mode (in which case the rcvif element will
* contain the address of the encX interface associated with the tunnel.
*/
static void
_ipip_input(struct mbuf *m, int iphlen, struct ifnet *gifp)
{
struct ip *ipo;
#ifdef INET6
struct ip6_hdr *ip6 = NULL;
u_int8_t itos;
#endif
int isr;
u_int8_t otos;
u_int8_t v;
int hlen;
IPIPSTAT_INC(ipips_ipackets);
m_copydata(m, 0, 1, &v);
switch (v >> 4) {
#ifdef INET
case 4:
hlen = sizeof(struct ip);
break;
#endif /* INET */
#ifdef INET6
case 6:
hlen = sizeof(struct ip6_hdr);
break;
#endif
default:
IPIPSTAT_INC(ipips_family);
m_freem(m);
return /* EAFNOSUPPORT */;
}
/* Bring the IP header in the first mbuf, if not there already */
if (m->m_len < hlen) {
if ((m = m_pullup(m, hlen)) == NULL) {
DPRINTF(("%s: m_pullup (1) failed\n", __func__));
IPIPSTAT_INC(ipips_hdrops);
return;
}
}
ipo = mtod(m, struct ip *);
/* Keep outer ecn field. */
switch (v >> 4) {
#ifdef INET
case 4:
otos = ipo->ip_tos;
break;
#endif /* INET */
#ifdef INET6
case 6:
otos = (ntohl(mtod(m, struct ip6_hdr *)->ip6_flow) >> 20) & 0xff;
break;
#endif
default:
panic("ipip_input: unknown ip version %u (outer)", v>>4);
}
/* Remove outer IP header */
m_adj(m, iphlen);
/* Sanity check */
if (m->m_pkthdr.len < sizeof(struct ip)) {
IPIPSTAT_INC(ipips_hdrops);
m_freem(m);
return;
}
m_copydata(m, 0, 1, &v);
switch (v >> 4) {
#ifdef INET
case 4:
hlen = sizeof(struct ip);
break;
#endif /* INET */
#ifdef INET6
case 6:
hlen = sizeof(struct ip6_hdr);
break;
#endif
default:
IPIPSTAT_INC(ipips_family);
m_freem(m);
return; /* EAFNOSUPPORT */
}
/*
* Bring the inner IP header in the first mbuf, if not there already.
*/
if (m->m_len < hlen) {
if ((m = m_pullup(m, hlen)) == NULL) {
DPRINTF(("%s: m_pullup (2) failed\n", __func__));
IPIPSTAT_INC(ipips_hdrops);
return;
}
}
/*
* RFC 1853 specifies that the inner TTL should not be touched on
* decapsulation. There's no reason this comment should be here, but
* this is as good as any a position.
*/
/* Some sanity checks in the inner IP header */
switch (v >> 4) {
#ifdef INET
case 4:
ipo = mtod(m, struct ip *);
ip_ecn_egress(V_ip4_ipsec_ecn, &otos, &ipo->ip_tos);
break;
#endif /* INET */
#ifdef INET6
case 6:
ip6 = (struct ip6_hdr *) ipo;
itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
ip_ecn_egress(V_ip6_ipsec_ecn, &otos, &itos);
ip6->ip6_flow &= ~htonl(0xff << 20);
ip6->ip6_flow |= htonl((u_int32_t) itos << 20);
break;
#endif
default:
panic("ipip_input: unknown ip version %u (inner)", v>>4);
}
/* Check for local address spoofing. */
if ((m->m_pkthdr.rcvif == NULL ||
!(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK)) &&
V_ipip_allow != 2) {
#ifdef INET
if ((v >> 4) == IPVERSION &&
in_localip(ipo->ip_src) != 0) {
IPIPSTAT_INC(ipips_spoof);
m_freem(m);
return;
}
#endif
#ifdef INET6
if ((v & IPV6_VERSION_MASK) == IPV6_VERSION &&
in6_localip(&ip6->ip6_src) != 0) {
IPIPSTAT_INC(ipips_spoof);
m_freem(m);
return;
}
#endif
}
/* Statistics */
IPIPSTAT_ADD(ipips_ibytes, m->m_pkthdr.len - iphlen);
/*
* Interface pointer stays the same; if no IPsec processing has
* been done (or will be done), this will point to a normal
* interface. Otherwise, it'll point to an enc interface, which
* will allow a packet filter to distinguish between secure and
* untrusted packets.
*/
switch (v >> 4) {
#ifdef INET
case 4:
isr = NETISR_IP;
break;
#endif
#ifdef INET6
case 6:
isr = NETISR_IPV6;
break;
#endif
default:
panic("%s: bogus ip version %u", __func__, v>>4);
}
if (netisr_queue(isr, m)) { /* (0) on success. */
IPIPSTAT_INC(ipips_qfull);
DPRINTF(("%s: packet dropped because of full queue\n",
__func__));
}
}
int
ipip_output(
struct mbuf *m,
struct ipsecrequest *isr,
struct mbuf **mp,
int skip,
int protoff
)
ipip_output(struct mbuf *m, struct ipsecrequest *isr, struct mbuf **mp,
int skip, int protoff)
{
struct secasvar *sav;
u_int8_t tp, otos;
@ -383,7 +117,6 @@ ipip_output(
"address in SA %s/%08lx\n", __func__,
ipsec_address(&saidx->dst),
(u_long) ntohl(sav->spi)));
IPIPSTAT_INC(ipips_unspec);
error = EINVAL;
goto bad;
}
@ -391,7 +124,6 @@ ipip_output(
M_PREPEND(m, sizeof(struct ip), M_NOWAIT);
if (m == 0) {
DPRINTF(("%s: M_PREPEND failed\n", __func__));
IPIPSTAT_INC(ipips_hdrops);
error = ENOBUFS;
goto bad;
}
@ -463,22 +195,17 @@ ipip_output(
"address in SA %s/%08lx\n", __func__,
ipsec_address(&saidx->dst),
(u_long) ntohl(sav->spi)));
IPIPSTAT_INC(ipips_unspec);
error = ENOBUFS;
goto bad;
}
/* scoped address handling */
ip6 = mtod(m, struct ip6_hdr *);
if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src))
ip6->ip6_src.s6_addr16[1] = 0;
if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst))
ip6->ip6_dst.s6_addr16[1] = 0;
in6_clearscope(&ip6->ip6_src);
in6_clearscope(&ip6->ip6_dst);
M_PREPEND(m, sizeof(struct ip6_hdr), M_NOWAIT);
if (m == 0) {
DPRINTF(("%s: M_PREPEND failed\n", __func__));
IPIPSTAT_INC(ipips_hdrops);
error = ENOBUFS;
goto bad;
}
@ -532,39 +259,12 @@ ipip_output(
nofamily:
DPRINTF(("%s: unsupported protocol family %u\n", __func__,
saidx->dst.sa.sa_family));
IPIPSTAT_INC(ipips_family);
error = EAFNOSUPPORT; /* XXX diffs from openbsd */
goto bad;
}
IPIPSTAT_INC(ipips_opackets);
*mp = m;
#ifdef INET
if (saidx->dst.sa.sa_family == AF_INET) {
#if 0
if (sav->tdb_xform->xf_type == XF_IP4)
tdb->tdb_cur_bytes +=
m->m_pkthdr.len - sizeof(struct ip);
#endif
IPIPSTAT_ADD(ipips_obytes,
m->m_pkthdr.len - sizeof(struct ip));
}
#endif /* INET */
#ifdef INET6
if (saidx->dst.sa.sa_family == AF_INET6) {
#if 0
if (sav->tdb_xform->xf_type == XF_IP4)
tdb->tdb_cur_bytes +=
m->m_pkthdr.len - sizeof(struct ip6_hdr);
#endif
IPIPSTAT_ADD(ipips_obytes,
m->m_pkthdr.len - sizeof(struct ip6_hdr));
}
#endif /* INET6 */
return 0;
return (0);
bad:
if (m)
m_freem(m);
@ -572,8 +272,6 @@ ipip_output(
return (error);
}
#ifdef IPSEC
#if defined(INET) || defined(INET6)
static int
ipe4_init(struct secasvar *sav, struct xformsw *xsp)
{
@ -603,63 +301,10 @@ static struct xformsw ipe4_xformsw = {
ipe4_init, ipe4_zeroize, ipe4_input, ipip_output,
};
extern struct domain inetdomain;
#endif /* INET || INET6 */
#ifdef INET
static struct protosw ipe4_protosw = {
.pr_type = SOCK_RAW,
.pr_domain = &inetdomain,
.pr_protocol = IPPROTO_IPV4,
.pr_flags = PR_ATOMIC|PR_ADDR|PR_LASTHDR,
.pr_input = ip4_input,
.pr_ctloutput = rip_ctloutput,
.pr_usrreqs = &rip_usrreqs
};
#endif /* INET */
#if defined(INET6) && defined(INET)
static struct protosw ipe6_protosw = {
.pr_type = SOCK_RAW,
.pr_domain = &inetdomain,
.pr_protocol = IPPROTO_IPV6,
.pr_flags = PR_ATOMIC|PR_ADDR|PR_LASTHDR,
.pr_input = ip4_input6,
.pr_ctloutput = rip_ctloutput,
.pr_usrreqs = &rip_usrreqs
};
#endif /* INET6 && INET */
#ifdef INET
/*
* Check the encapsulated packet to see if we want it
*/
static int
ipe4_encapcheck(const struct mbuf *m, int off, int proto, void *arg)
{
/*
* Only take packets coming from IPSEC tunnels; the rest
* must be handled by the gif tunnel code. Note that we
* also return a minimum priority when we want the packet
* so any explicit gif tunnels take precedence.
*/
return ((m->m_flags & M_IPSEC) != 0 ? 1 : 0);
}
#endif /* INET */
static void
ipe4_attach(void)
{
xform_register(&ipe4_xformsw);
/* attach to encapsulation framework */
/* XXX save return cookie for detach on module remove */
#ifdef INET
(void) encap_attach_func(AF_INET, -1,
ipe4_encapcheck, &ipe4_protosw, NULL);
#endif
#if defined(INET6) && defined(INET)
(void) encap_attach_func(AF_INET6, -1,
ipe4_encapcheck, (struct protosw *)&ipe6_protosw, NULL);
#endif
}
SYSINIT(ipe4_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, ipe4_attach, NULL);
#endif /* IPSEC */