freebsd-dev/sys/net/if_enc.c
Andrew Thompson e361d7d421 Fix a panic where if the mbuf was consumed by the filter for requeueing
(dummynet), ipsec_filter() would return the empty error code and the ipsec code
would continue to forward/deference the null mbuf.

Found by:       m0n0wall
Reviewed by:    bz
MFC after:      3 days
2007-12-26 08:41:58 +00:00

374 lines
8.9 KiB
C

/*-
* Copyright (c) 2006 The FreeBSD Project.
* 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.
*
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/module.h>
#include <machine/bus.h>
#include <sys/rman.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <net/if_clone.h>
#include <net/if_types.h>
#include <net/pfil.h>
#include <net/route.h>
#include <net/netisr.h>
#include <net/bpf.h>
#include <net/bpfdesc.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#include <netinet/in_var.h>
#include "opt_inet6.h"
#ifdef INET6
#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
#endif
#include "opt_enc.h"
#include <netipsec/ipsec.h>
#include <netipsec/xform.h>
#define ENCMTU (1024+512)
/* XXX this define must have the same value as in OpenBSD */
#define M_CONF 0x0400 /* payload was encrypted (ESP-transport) */
#define M_AUTH 0x0800 /* payload was authenticated (AH or ESP auth) */
#define M_AUTH_AH 0x2000 /* header was authenticated (AH) */
struct enchdr {
u_int32_t af;
u_int32_t spi;
u_int32_t flags;
};
static struct ifnet *encif;
static struct mtx enc_mtx;
struct enc_softc {
struct ifnet *sc_ifp;
};
static int enc_ioctl(struct ifnet *, u_long, caddr_t);
static int enc_output(struct ifnet *ifp, struct mbuf *m,
struct sockaddr *dst, struct rtentry *rt);
static int enc_clone_create(struct if_clone *, int, caddr_t);
static void enc_clone_destroy(struct ifnet *);
IFC_SIMPLE_DECLARE(enc, 1);
/*
* Sysctls.
*/
/*
* Before and after are relative to when we are stripping the
* outer IP header.
*/
SYSCTL_NODE(_net, OID_AUTO, enc, CTLFLAG_RW, 0, "enc sysctl");
SYSCTL_NODE(_net_enc, OID_AUTO, in, CTLFLAG_RW, 0, "enc input sysctl");
static int ipsec_filter_mask_in = ENC_BEFORE;
SYSCTL_XINT(_net_enc_in, OID_AUTO, ipsec_filter_mask, CTLFLAG_RW,
&ipsec_filter_mask_in, 0, "IPsec input firewall filter mask");
static int ipsec_bpf_mask_in = ENC_BEFORE;
SYSCTL_XINT(_net_enc_in, OID_AUTO, ipsec_bpf_mask, CTLFLAG_RW,
&ipsec_bpf_mask_in, 0, "IPsec input bpf mask");
SYSCTL_NODE(_net_enc, OID_AUTO, out, CTLFLAG_RW, 0, "enc output sysctl");
static int ipsec_filter_mask_out = ENC_BEFORE;
SYSCTL_XINT(_net_enc_out, OID_AUTO, ipsec_filter_mask, CTLFLAG_RW,
&ipsec_filter_mask_out, 0, "IPsec output firewall filter mask");
static int ipsec_bpf_mask_out = ENC_BEFORE|ENC_AFTER;
SYSCTL_XINT(_net_enc_out, OID_AUTO, ipsec_bpf_mask, CTLFLAG_RW,
&ipsec_bpf_mask_out, 0, "IPsec output bpf mask");
static void
enc_clone_destroy(struct ifnet *ifp)
{
KASSERT(ifp != encif, ("%s: destroying encif", __func__));
bpfdetach(ifp);
if_detach(ifp);
if_free(ifp);
}
static int
enc_clone_create(struct if_clone *ifc, int unit, caddr_t params)
{
struct ifnet *ifp;
struct enc_softc *sc;
sc = malloc(sizeof(*sc), M_DEVBUF, M_WAITOK|M_ZERO);
ifp = sc->sc_ifp = if_alloc(IFT_ENC);
if (ifp == NULL) {
free(sc, M_DEVBUF);
return (ENOSPC);
}
if_initname(ifp, ifc->ifc_name, unit);
ifp->if_mtu = ENCMTU;
ifp->if_ioctl = enc_ioctl;
ifp->if_output = enc_output;
ifp->if_snd.ifq_maxlen = ifqmaxlen;
ifp->if_softc = sc;
if_attach(ifp);
bpfattach(ifp, DLT_ENC, sizeof(struct enchdr));
mtx_lock(&enc_mtx);
/* grab a pointer to enc0, ignore the rest */
if (encif == NULL)
encif = ifp;
mtx_unlock(&enc_mtx);
return (0);
}
static int
enc_modevent(module_t mod, int type, void *data)
{
switch (type) {
case MOD_LOAD:
mtx_init(&enc_mtx, "enc mtx", NULL, MTX_DEF);
if_clone_attach(&enc_cloner);
break;
case MOD_UNLOAD:
printf("enc module unload - not possible for this module\n");
return (EINVAL);
default:
return (EOPNOTSUPP);
}
return (0);
}
static moduledata_t enc_mod = {
"enc",
enc_modevent,
0
};
DECLARE_MODULE(enc, enc_mod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY);
static int
enc_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
struct rtentry *rt)
{
m_freem(m);
return (0);
}
/*
* Process an ioctl request.
*/
/* ARGSUSED */
static int
enc_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
{
int error = 0;
mtx_lock(&enc_mtx);
switch (cmd) {
case SIOCSIFFLAGS:
if (ifp->if_flags & IFF_UP)
ifp->if_drv_flags |= IFF_DRV_RUNNING;
else
ifp->if_drv_flags &= ~IFF_DRV_RUNNING;
break;
default:
error = EINVAL;
}
mtx_unlock(&enc_mtx);
return (error);
}
int
ipsec_filter(struct mbuf **mp, int dir, int flags)
{
int error, i;
struct ip *ip;
KASSERT(encif != NULL, ("%s: encif is null", __func__));
KASSERT(flags & (ENC_IN|ENC_OUT),
("%s: invalid flags: %04x", __func__, flags));
if ((encif->if_drv_flags & IFF_DRV_RUNNING) == 0)
return (0);
if (flags & ENC_IN) {
if ((flags & ipsec_filter_mask_in) == 0)
return (0);
} else {
if ((flags & ipsec_filter_mask_out) == 0)
return (0);
}
/* Skip pfil(9) if no filters are loaded */
if (!(PFIL_HOOKED(&inet_pfil_hook)
#ifdef INET6
|| PFIL_HOOKED(&inet6_pfil_hook)
#endif
)) {
return (0);
}
i = min((*mp)->m_pkthdr.len, max_protohdr);
if ((*mp)->m_len < i) {
*mp = m_pullup(*mp, i);
if (*mp == NULL) {
printf("%s: m_pullup failed\n", __func__);
return (-1);
}
}
error = 0;
ip = mtod(*mp, struct ip *);
switch (ip->ip_v) {
case 4:
/*
* before calling the firewall, swap fields the same as
* IP does. here we assume the header is contiguous
*/
ip->ip_len = ntohs(ip->ip_len);
ip->ip_off = ntohs(ip->ip_off);
error = pfil_run_hooks(&inet_pfil_hook, mp,
encif, dir, NULL);
if (*mp == NULL || error != 0)
break;
/* restore byte ordering */
ip = mtod(*mp, struct ip *);
ip->ip_len = htons(ip->ip_len);
ip->ip_off = htons(ip->ip_off);
break;
#ifdef INET6
case 6:
error = pfil_run_hooks(&inet6_pfil_hook, mp,
encif, dir, NULL);
break;
#endif
default:
printf("%s: unknown IP version\n", __func__);
}
/*
* If the mbuf was consumed by the filter for requeueing (dummynet, etc)
* then error will be zero but we still want to return an error to our
* caller so the null mbuf isn't forwarded further.
*/
if (*mp == NULL && error == 0)
return (-1); /* Consumed by the filter */
if (*mp == NULL)
return (error);
if (error != 0)
goto bad;
return (error);
bad:
m_freem(*mp);
*mp = NULL;
return (error);
}
void
ipsec_bpf(struct mbuf *m, struct secasvar *sav, int af, int flags)
{
int mflags;
struct enchdr hdr;
KASSERT(encif != NULL, ("%s: encif is null", __func__));
KASSERT(flags & (ENC_IN|ENC_OUT),
("%s: invalid flags: %04x", __func__, flags));
if ((encif->if_drv_flags & IFF_DRV_RUNNING) == 0)
return;
if (flags & ENC_IN) {
if ((flags & ipsec_bpf_mask_in) == 0)
return;
} else {
if ((flags & ipsec_bpf_mask_out) == 0)
return;
}
if (bpf_peers_present(encif->if_bpf)) {
mflags = 0;
hdr.spi = 0;
if (!sav) {
struct m_tag *mtag;
mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
if (mtag != NULL) {
struct tdb_ident *tdbi;
tdbi = (struct tdb_ident *) (mtag + 1);
if (tdbi->alg_enc != SADB_EALG_NONE)
mflags |= M_CONF;
if (tdbi->alg_auth != SADB_AALG_NONE)
mflags |= M_AUTH;
hdr.spi = tdbi->spi;
}
} else {
if (sav->alg_enc != SADB_EALG_NONE)
mflags |= M_CONF;
if (sav->alg_auth != SADB_AALG_NONE)
mflags |= M_AUTH;
hdr.spi = sav->spi;
}
/*
* 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).
*/
hdr.af = af;
/* hdr.spi already set above */
hdr.flags = mflags;
bpf_mtap2(encif->if_bpf, &hdr, sizeof(hdr), m);
}
}