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NetBSD/sys/netipsec/ipsec.c

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/* $NetBSD: ipsec.c,v 1.179 2024/05/13 00:12:33 msaitoh Exp $ */
/* $FreeBSD: ipsec.c,v 1.2.2.2 2003/07/01 01:38:13 sam Exp $ */
/* $KAME: ipsec.c,v 1.103 2001/05/24 07:14:18 sakane Exp $ */
/*
* Copyright (C) 1995, 1996, 1997, and 1998 WIDE 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.
* 3. Neither the name of the project nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE PROJECT 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 PROJECT 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>
__KERNEL_RCSID(0, "$NetBSD: ipsec.c,v 1.179 2024/05/13 00:12:33 msaitoh Exp $");
/*
* IPsec controller part.
*/
#if defined(_KERNEL_OPT)
#include "opt_inet.h"
#include "opt_ipsec.h"
#endif
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/domain.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/errno.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <sys/syslog.h>
#include <sys/sysctl.h>
#include <sys/proc.h>
#include <sys/kauth.h>
#include <sys/cpu.h>
#include <sys/kmem.h>
#include <sys/pserialize.h>
#include <net/if.h>
#include <net/route.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 <netinet/udp.h>
#include <netinet/udp_var.h>
#include <netinet/tcp.h>
#include <netinet/udp.h>
#include <netinet/ip_icmp.h>
#include <netinet/ip_private.h>
#include <netinet/ip6.h>
#ifdef INET6
#include <netinet6/ip6_var.h>
#endif
#include <netinet/in_pcb.h>
#include <netinet/in_offload.h>
#ifdef INET6
#include <netinet6/in6_pcb.h>
#include <netinet/icmp6.h>
#endif
#include <netipsec/ipsec.h>
#include <netipsec/ipsec_var.h>
#include <netipsec/ipsec_private.h>
#ifdef INET6
#include <netipsec/ipsec6.h>
#endif
#include <netipsec/ah_var.h>
#include <netipsec/esp_var.h>
#include <netipsec/ipcomp.h> /*XXX*/
#include <netipsec/ipcomp_var.h>
#include <netipsec/key.h>
#include <netipsec/keydb.h>
#include <netipsec/key_debug.h>
#include <netipsec/xform.h>
int ipsec_used = 0;
int ipsec_enabled = 1;
#ifdef IPSEC_DEBUG
int ipsec_debug = 1;
/*
* When set to 1, IPsec will send packets with the same sequence number.
* This allows to verify if the other side has proper replay attacks detection.
*/
int ipsec_replay = 0;
/*
* When set 1, IPsec will send packets with corrupted HMAC.
* This allows to verify if the other side properly detects modified packets.
*/
int ipsec_integrity = 0;
#else
int ipsec_debug = 0;
#endif
percpu_t *ipsecstat_percpu;
int ip4_ah_offsetmask = 0; /* maybe IP_DF? */
int ip4_ipsec_dfbit = 2; /* DF bit on encap. 0: clear 1: set 2: copy */
int ip4_esp_trans_deflev = IPSEC_LEVEL_USE;
int ip4_esp_net_deflev = IPSEC_LEVEL_USE;
int ip4_ah_trans_deflev = IPSEC_LEVEL_USE;
int ip4_ah_net_deflev = IPSEC_LEVEL_USE;
struct secpolicy ip4_def_policy;
int ip4_ipsec_ecn = 0; /* ECN ignore(-1)/forbidden(0)/allowed(1) */
u_int ipsec_spdgen = 1; /* SPD generation # */
static struct secpolicy ipsec_dummy_sp __read_mostly = {
.state = IPSEC_SPSTATE_ALIVE,
/* If ENTRUST, the dummy SP never be used. See ipsec_getpolicybysock. */
.policy = IPSEC_POLICY_ENTRUST,
};
static struct secpolicy *ipsec_checkpcbcache(struct mbuf *,
struct inpcbpolicy *, int);
static int ipsec_fillpcbcache(struct inpcbpolicy *, struct mbuf *,
struct secpolicy *, int);
static int ipsec_invalpcbcache(struct inpcbpolicy *, int);
/*
* Crypto support requirements:
*
* 1 require hardware support
* -1 require software support
* 0 take anything
*/
int crypto_support = 0;
static struct secpolicy *ipsec_getpolicybysock(struct mbuf *, u_int,
struct inpcb *, int *);
#ifdef INET6
int ip6_esp_trans_deflev = IPSEC_LEVEL_USE;
int ip6_esp_net_deflev = IPSEC_LEVEL_USE;
int ip6_ah_trans_deflev = IPSEC_LEVEL_USE;
int ip6_ah_net_deflev = IPSEC_LEVEL_USE;
struct secpolicy ip6_def_policy;
int ip6_ipsec_ecn = 0; /* ECN ignore(-1)/forbidden(0)/allowed(1) */
#endif
static int ipsec_setspidx_inpcb(struct mbuf *, struct inpcb *);
static int ipsec_setspidx(struct mbuf *, struct secpolicyindex *, int, int);
static void ipsec4_get_ulp(struct mbuf *m, struct secpolicyindex *, int);
static int ipsec4_setspidx_ipaddr(struct mbuf *, struct secpolicyindex *);
#ifdef INET6
static void ipsec6_get_ulp(struct mbuf *m, struct secpolicyindex *, int);
static int ipsec6_setspidx_ipaddr(struct mbuf *, struct secpolicyindex *);
#endif
static void ipsec_delpcbpolicy(struct inpcbpolicy *);
static void ipsec_destroy_policy(struct secpolicy *);
static int ipsec_sp_reject(const struct secpolicy *, const struct mbuf *);
static void vshiftl(unsigned char *, int, int);
static size_t ipsec_sp_hdrsiz(const struct secpolicy *, const struct mbuf *);
/*
* Try to validate and use cached policy on a PCB.
*/
static struct secpolicy *
ipsec_checkpcbcache(struct mbuf *m, struct inpcbpolicy *pcbsp, int dir)
{
struct secpolicyindex spidx;
struct secpolicy *sp = NULL;
int s;
KASSERT(IPSEC_DIR_IS_VALID(dir));
KASSERT(pcbsp != NULL);
KASSERT(dir < __arraycount(pcbsp->sp_cache));
KASSERT(inp_locked(pcbsp->sp_inp));
/*
* Checking the generation and sp->state and taking a reference to an SP
* must be in a critical section of pserialize. See key_unlink_sp.
*/
s = pserialize_read_enter();
/* SPD table change invalidate all the caches. */
if (ipsec_spdgen != pcbsp->sp_cache[dir].cachegen) {
ipsec_invalpcbcache(pcbsp, dir);
goto out;
}
sp = pcbsp->sp_cache[dir].cachesp;
if (sp == NULL)
goto out;
if (sp->state != IPSEC_SPSTATE_ALIVE) {
sp = NULL;
ipsec_invalpcbcache(pcbsp, dir);
goto out;
}
if ((pcbsp->sp_cacheflags & IPSEC_PCBSP_CONNECTED) == 0) {
/* NB: assume ipsec_setspidx never sleep */
if (ipsec_setspidx(m, &spidx, dir, 1) != 0) {
sp = NULL;
goto out;
}
/*
* We have to make an exact match here since the cached rule
* might have lower priority than a rule that would otherwise
* have matched the packet.
*/
if (memcmp(&pcbsp->sp_cache[dir].cacheidx, &spidx,
sizeof(spidx))) {
sp = NULL;
goto out;
}
} else {
/*
* The pcb is connected, and the L4 code is sure that:
* - outgoing side uses inp_[lf]addr
* - incoming side looks up policy after inpcb lookup
* and address pair is know to be stable. We do not need
* to generate spidx again, nor check the address match again.
*
* For IPv4/v6 SOCK_STREAM sockets, this assumptions holds
* and there are calls to ipsec_pcbconn() from inpcb_connect().
*/
}
key_sp_touch(sp);
KEY_SP_REF(sp);
KEYDEBUG_PRINTF(KEYDEBUG_IPSEC_STAMP,
"DP cause refcnt++:%d SP:%p\n",
key_sp_refcnt(sp), pcbsp->sp_cache[dir].cachesp);
out:
pserialize_read_exit(s);
return sp;
}
static int
ipsec_fillpcbcache(struct inpcbpolicy *pcbsp, struct mbuf *m,
struct secpolicy *sp, int dir)
{
KASSERT(IPSEC_DIR_IS_INOROUT(dir));
KASSERT(dir < __arraycount(pcbsp->sp_cache));
KASSERT(inp_locked(pcbsp->sp_inp));
pcbsp->sp_cache[dir].cachesp = NULL;
pcbsp->sp_cache[dir].cachehint = IPSEC_PCBHINT_UNKNOWN;
if (ipsec_setspidx(m, &pcbsp->sp_cache[dir].cacheidx, dir, 1) != 0) {
return EINVAL;
}
pcbsp->sp_cache[dir].cachesp = sp;
if (pcbsp->sp_cache[dir].cachesp) {
/*
* If the PCB is connected, we can remember a hint to
* possibly short-circuit IPsec processing in other places.
*/
if (pcbsp->sp_cacheflags & IPSEC_PCBSP_CONNECTED) {
switch (pcbsp->sp_cache[dir].cachesp->policy) {
case IPSEC_POLICY_NONE:
case IPSEC_POLICY_BYPASS:
pcbsp->sp_cache[dir].cachehint =
IPSEC_PCBHINT_NO;
break;
default:
pcbsp->sp_cache[dir].cachehint =
IPSEC_PCBHINT_YES;
}
}
}
pcbsp->sp_cache[dir].cachegen = ipsec_spdgen;
return 0;
}
static int
ipsec_invalpcbcache(struct inpcbpolicy *pcbsp, int dir)
{
int i;
KASSERT(inp_locked(pcbsp->sp_inp));
for (i = IPSEC_DIR_INBOUND; i <= IPSEC_DIR_OUTBOUND; i++) {
if (dir != IPSEC_DIR_ANY && i != dir)
continue;
pcbsp->sp_cache[i].cachesp = NULL;
pcbsp->sp_cache[i].cachehint = IPSEC_PCBHINT_UNKNOWN;
pcbsp->sp_cache[i].cachegen = 0;
memset(&pcbsp->sp_cache[i].cacheidx, 0,
sizeof(pcbsp->sp_cache[i].cacheidx));
}
return 0;
}
void
ipsec_pcbconn(struct inpcbpolicy *pcbsp)
{
KASSERT(inp_locked(pcbsp->sp_inp));
pcbsp->sp_cacheflags |= IPSEC_PCBSP_CONNECTED;
ipsec_invalpcbcache(pcbsp, IPSEC_DIR_ANY);
}
void
ipsec_pcbdisconn(struct inpcbpolicy *pcbsp)
{
KASSERT(inp_locked(pcbsp->sp_inp));
pcbsp->sp_cacheflags &= ~IPSEC_PCBSP_CONNECTED;
ipsec_invalpcbcache(pcbsp, IPSEC_DIR_ANY);
}
void
ipsec_invalpcbcacheall(void)
{
if (ipsec_spdgen == UINT_MAX)
ipsec_spdgen = 1;
else
ipsec_spdgen++;
}
/*
* Return a held reference to the default SP.
*/
static struct secpolicy *
key_get_default_sp(int af, const char *where, int tag)
{
struct secpolicy *sp;
KEYDEBUG_PRINTF(KEYDEBUG_IPSEC_STAMP, "DP from %s:%u\n", where, tag);
switch(af) {
case AF_INET:
sp = &ip4_def_policy;
break;
#ifdef INET6
case AF_INET6:
sp = &ip6_def_policy;
break;
#endif
default:
KEYDEBUG_PRINTF(KEYDEBUG_IPSEC_STAMP,
"unexpected protocol family %u\n", af);
return NULL;
}
if (sp->policy != IPSEC_POLICY_DISCARD &&
sp->policy != IPSEC_POLICY_NONE) {
IPSECLOG(LOG_INFO, "fixed system default policy: %d->%d\n",
sp->policy, IPSEC_POLICY_NONE);
sp->policy = IPSEC_POLICY_NONE;
}
KEY_SP_REF(sp);
KEYDEBUG_PRINTF(KEYDEBUG_IPSEC_STAMP, "DP returns SP:%p (%u)\n",
sp, key_sp_refcnt(sp));
return sp;
}
#define KEY_GET_DEFAULT_SP(af) \
key_get_default_sp((af), __func__, __LINE__)
/*
* For OUTBOUND packet having a socket. Searching SPD for packet,
* and return a pointer to SP.
* OUT: NULL: no appropriate SP found, the following value is set to error.
* 0 : bypass
* EACCES : discard packet.
* ENOENT : ipsec_acquire() in progress, maybe.
* others : error occurred.
* others: a pointer to SP
*
* NOTE: IPv6 mapped address concern is implemented here.
*/
static struct secpolicy *
ipsec_getpolicybysock(struct mbuf *m, u_int dir, struct inpcb *inp,
int *error)
{
struct inpcbpolicy *pcbsp = NULL;
struct secpolicy *currsp = NULL; /* policy on socket */
struct secpolicy *sp;
int af;
KASSERT(m != NULL);
KASSERT(inp != NULL);
KASSERT(error != NULL);
KASSERTMSG(IPSEC_DIR_IS_INOROUT(dir), "invalid direction %u", dir);
KASSERT(inp->inp_socket != NULL);
KASSERT(inp_locked(inp));
/* XXX FIXME inpcb vs socket*/
af = inp->inp_af;
KASSERTMSG(af == AF_INET || af == AF_INET6,
"unexpected protocol family %u", af);
KASSERT(inp->inp_sp != NULL);
/* If we have a cached entry, and if it is still valid, use it. */
IPSEC_STATINC(IPSEC_STAT_SPDCACHELOOKUP);
currsp = ipsec_checkpcbcache(m, inp->inp_sp, dir);
if (currsp) {
*error = 0;
return currsp;
}
IPSEC_STATINC(IPSEC_STAT_SPDCACHEMISS);
switch (af) {
case AF_INET:
#if defined(INET6)
case AF_INET6:
#endif
*error = ipsec_setspidx_inpcb(m, inp);
pcbsp = inp->inp_sp;
break;
default:
*error = EPFNOSUPPORT;
break;
}
if (*error)
return NULL;
KASSERT(pcbsp != NULL);
switch (dir) {
case IPSEC_DIR_INBOUND:
currsp = pcbsp->sp_in;
break;
case IPSEC_DIR_OUTBOUND:
currsp = pcbsp->sp_out;
break;
}
KASSERT(currsp != NULL);
if (pcbsp->priv) { /* when privileged socket */
switch (currsp->policy) {
case IPSEC_POLICY_BYPASS:
case IPSEC_POLICY_IPSEC:
KEY_SP_REF(currsp);
sp = currsp;
break;
case IPSEC_POLICY_ENTRUST:
/* look for a policy in SPD */
if (key_havesp(dir))
sp = KEY_LOOKUP_SP_BYSPIDX(&currsp->spidx, dir);
else
sp = NULL;
if (sp == NULL) /* no SP found */
sp = KEY_GET_DEFAULT_SP(af);
break;
default:
IPSECLOG(LOG_ERR, "Invalid policy for PCB %d\n",
currsp->policy);
*error = EINVAL;
return NULL;
}
} else { /* unpriv, SPD has policy */
if (key_havesp(dir))
sp = KEY_LOOKUP_SP_BYSPIDX(&currsp->spidx, dir);
else
sp = NULL;
if (sp == NULL) { /* no SP found */
switch (currsp->policy) {
case IPSEC_POLICY_BYPASS:
IPSECLOG(LOG_ERR, "Illegal policy for "
"non-privileged defined %d\n",
currsp->policy);
*error = EINVAL;
return NULL;
case IPSEC_POLICY_ENTRUST:
sp = KEY_GET_DEFAULT_SP(af);
break;
case IPSEC_POLICY_IPSEC:
KEY_SP_REF(currsp);
sp = currsp;
break;
default:
IPSECLOG(LOG_ERR, "Invalid policy for "
"PCB %d\n", currsp->policy);
*error = EINVAL;
return NULL;
}
}
}
KASSERTMSG(sp != NULL, "null SP (priv %u policy %u", pcbsp->priv,
currsp->policy);
KEYDEBUG_PRINTF(KEYDEBUG_IPSEC_STAMP,
"DP (priv %u policy %u) allocates SP:%p (refcnt %u)\n",
pcbsp->priv, currsp->policy, sp, key_sp_refcnt(sp));
ipsec_fillpcbcache(pcbsp, m, sp, dir);
return sp;
}
/*
* For FORWARDING packet or OUTBOUND without a socket. Searching SPD for packet,
* and return a pointer to SP.
* OUT: positive: a pointer to the entry for security policy leaf matched.
* NULL: no appropriate SP found, the following value is set to error.
* 0 : bypass
* EACCES : discard packet.
* ENOENT : ipsec_acquire() in progress, maybe.
* others : error occurred.
*/
static struct secpolicy *
ipsec_getpolicybyaddr(struct mbuf *m, u_int dir, int flag, int *error)
{
struct secpolicyindex spidx;
struct secpolicy *sp;
KASSERT(m != NULL);
KASSERT(error != NULL);
KASSERTMSG(IPSEC_DIR_IS_INOROUT(dir), "invalid direction %u", dir);
sp = NULL;
/* Make an index to look for a policy. */
*error = ipsec_setspidx(m, &spidx, dir, 1);
if (*error != 0) {
IPSECLOG(LOG_DEBUG, "setpidx failed, dir %u flag %u\n", dir, flag);
memset(&spidx, 0, sizeof(spidx));
return NULL;
}
spidx.dir = dir;
if (key_havesp(dir)) {
sp = KEY_LOOKUP_SP_BYSPIDX(&spidx, dir);
}
if (sp == NULL) {
/* no SP found, use system default */
sp = KEY_GET_DEFAULT_SP(spidx.dst.sa.sa_family);
}
KASSERT(sp != NULL);
return sp;
}
static struct secpolicy *
ipsec_checkpolicy(struct mbuf *m, u_int dir, u_int flag, int *error,
struct inpcb *inp)
{
struct secpolicy *sp;
*error = 0;
if (inp == NULL) {
sp = ipsec_getpolicybyaddr(m, dir, flag, error);
} else {
KASSERT(inp->inp_socket != NULL);
sp = ipsec_getpolicybysock(m, dir, inp, error);
}
if (sp == NULL) {
KASSERTMSG(*error != 0, "getpolicy failed w/o error");
IPSEC_STATINC(IPSEC_STAT_OUT_INVAL);
return NULL;
}
KASSERTMSG(*error == 0, "sp w/ error set to %u", *error);
switch (sp->policy) {
case IPSEC_POLICY_ENTRUST:
default:
printf("%s: invalid policy %u\n", __func__, sp->policy);
/* fall thru... */
case IPSEC_POLICY_DISCARD:
IPSEC_STATINC(IPSEC_STAT_OUT_POLVIO);
*error = -EINVAL; /* packet is discarded by caller */
break;
case IPSEC_POLICY_BYPASS:
case IPSEC_POLICY_NONE:
KEY_SP_UNREF(&sp);
sp = NULL; /* NB: force NULL result */
break;
case IPSEC_POLICY_IPSEC:
KASSERT(sp->req != NULL);
break;
}
if (*error != 0) {
KEY_SP_UNREF(&sp);
sp = NULL;
IPSECLOG(LOG_DEBUG, "done, error %d\n", *error);
}
return sp;
}
int
ipsec4_output(struct mbuf *m, struct inpcb *inp, int flags,
u_long *mtu, bool *natt_frag, bool *done, bool *count_drop)
{
struct secpolicy *sp = NULL;
u_long _mtu = 0;
int error;
/*
* Check the security policy (SP) for the packet and, if required,
* do IPsec-related processing. There are two cases here; the first
* time a packet is sent through it will be untagged and handled by
* ipsec_checkpolicy(). If the packet is resubmitted to ip_output
* (e.g. after AH, ESP, etc. processing), there will be a tag to
* bypass the lookup and related policy checking.
*/
if (ipsec_outdone(m)) {
return 0;
}
if (inp && ipsec_pcb_skip_ipsec(inp->inp_sp, IPSEC_DIR_OUTBOUND)) {
return 0;
}
sp = ipsec_checkpolicy(m, IPSEC_DIR_OUTBOUND, flags, &error, inp);
/*
* There are four return cases:
* sp != NULL apply IPsec policy
* sp == NULL, error == 0 no IPsec handling needed
* sp == NULL, error == -EINVAL discard packet w/o error
* sp == NULL, error != 0 discard packet, report error
*/
if (sp == NULL) {
if (error) {
/*
* Hack: -EINVAL is used to signal that a packet
* should be silently discarded. This is typically
* because we asked key management for an SA and
* it was delayed (e.g. kicked up to IKE).
*/
if (error == -EINVAL)
error = 0;
m_freem(m);
*done = true;
*count_drop = true;
return error;
}
/* No IPsec processing for this packet. */
return 0;
}
/*
* Do delayed checksums now because we send before
* this is done in the normal processing path.
*/
if (m->m_pkthdr.csum_flags & (M_CSUM_TCPv4|M_CSUM_UDPv4)) {
in_undefer_cksum_tcpudp(m);
m->m_pkthdr.csum_flags &= ~(M_CSUM_TCPv4|M_CSUM_UDPv4);
}
error = ipsec4_process_packet(m, sp->req, &_mtu);
if (error == 0 && _mtu != 0) {
/*
* NAT-T ESP fragmentation: do not do IPSec processing
* now, we will do it on each fragmented packet.
*/
*mtu = _mtu;
*natt_frag = true;
KEY_SP_UNREF(&sp);
return 0;
}
/*
* Preserve KAME behaviour: ENOENT can be returned
* when an SA acquire is in progress. Don't propagate
* this to user-level; it confuses applications.
*
* XXX this will go away when the SADB is redone.
*/
if (error == ENOENT)
error = 0;
KEY_SP_UNREF(&sp);
*done = true;
return error;
}
int
ipsec_ip_input_checkpolicy(struct mbuf *m, bool forward)
{
struct secpolicy *sp;
int error;
error = ipsec_in_reject(m, NULL);
if (error) {
return EINVAL;
}
if (!forward || !(m->m_flags & M_CANFASTFWD)) {
return 0;
}
/*
* Peek at the outbound SP for this packet to determine if
* it is a Fast Forward candidate.
*/
sp = ipsec_checkpolicy(m, IPSEC_DIR_OUTBOUND, IP_FORWARDING,
&error, NULL);
if (sp != NULL) {
m->m_flags &= ~M_CANFASTFWD;
KEY_SP_UNREF(&sp);
}
return 0;
}
/*
* If the packet is routed over IPsec tunnel, tell the originator the
* tunnel MTU.
* tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz
*
* XXX: Quick hack!!!
*
* XXX: And what if the MTU goes negative?
*/
void
ipsec_mtu(struct mbuf *m, int *destmtu)
{
struct secpolicy *sp;
size_t ipsechdr;
int error;
sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND, IP_FORWARDING,
&error);
if (sp == NULL) {
return;
}
/* Count IPsec header size. */
ipsechdr = ipsec_sp_hdrsiz(sp, m);
/*
* Find the correct route for outer IP header, compute tunnel MTU.
*/
if (sp->req) {
struct secasvar *sav;
sav = ipsec_lookup_sa(sp->req, m);
if (sav != NULL) {
struct route *ro;
struct rtentry *rt;
ro = &sav->sah->sa_route;
rt = rtcache_validate(ro);
if (rt && rt->rt_ifp) {
*destmtu = rt->rt_rmx.rmx_mtu ?
rt->rt_rmx.rmx_mtu : rt->rt_ifp->if_mtu;
*destmtu -= ipsechdr;
}
rtcache_unref(rt, ro);
KEY_SA_UNREF(&sav);
}
}
KEY_SP_UNREF(&sp);
}
static int
ipsec_setspidx_inpcb(struct mbuf *m, struct inpcb *inp)
{
int error;
KASSERT(inp != NULL);
KASSERT(inp->inp_sp != NULL);
KASSERT(inp->inp_sp->sp_out != NULL);
KASSERT(inp->inp_sp->sp_in != NULL);
error = ipsec_setspidx(m, &inp->inp_sp->sp_in->spidx,
IPSEC_DIR_INBOUND, 1);
if (error == 0) {
inp->inp_sp->sp_out->spidx = inp->inp_sp->sp_in->spidx;
inp->inp_sp->sp_out->spidx.dir = IPSEC_DIR_OUTBOUND;
} else {
memset(&inp->inp_sp->sp_in->spidx, 0,
sizeof(inp->inp_sp->sp_in->spidx));
memset(&inp->inp_sp->sp_out->spidx, 0,
sizeof(inp->inp_sp->sp_out->spidx));
}
return error;
}
/*
* configure security policy index (src/dst/proto/sport/dport)
* by looking at the content of mbuf.
* the caller is responsible for error recovery (like clearing up spidx).
*/
static int
ipsec_setspidx(struct mbuf *m, struct secpolicyindex *spidx, int dir,
int needport)
{
struct ip *ip = NULL;
struct ip ipbuf;
u_int v;
int error;
KASSERT(m != NULL);
M_VERIFY_PACKET(m);
if (m->m_pkthdr.len < sizeof(struct ip)) {
KEYDEBUG_PRINTF(KEYDEBUG_IPSEC_DUMP,
"pkthdr.len(%d) < sizeof(struct ip), ignored.\n",
m->m_pkthdr.len);
return EINVAL;
}
memset(spidx, 0, sizeof(*spidx));
spidx->dir = dir;
if (m->m_len >= sizeof(*ip)) {
ip = mtod(m, struct ip *);
} else {
m_copydata(m, 0, sizeof(ipbuf), &ipbuf);
ip = &ipbuf;
}
v = ip->ip_v;
switch (v) {
case 4:
error = ipsec4_setspidx_ipaddr(m, spidx);
if (error)
return error;
ipsec4_get_ulp(m, spidx, needport);
return 0;
#ifdef INET6
case 6:
if (m->m_pkthdr.len < sizeof(struct ip6_hdr)) {
KEYDEBUG_PRINTF(KEYDEBUG_IPSEC_DUMP,
"pkthdr.len(%d) < sizeof(struct ip6_hdr), "
"ignored.\n", m->m_pkthdr.len);
return EINVAL;
}
error = ipsec6_setspidx_ipaddr(m, spidx);
if (error)
return error;
ipsec6_get_ulp(m, spidx, needport);
return 0;
#endif
default:
KEYDEBUG_PRINTF(KEYDEBUG_IPSEC_DUMP,
"unknown IP version %u, ignored.\n", v);
return EINVAL;
}
}
static void
ipsec4_get_ulp(struct mbuf *m, struct secpolicyindex *spidx, int needport)
{
u_int8_t nxt;
int off;
KASSERT(m != NULL);
KASSERTMSG(m->m_pkthdr.len >= sizeof(struct ip), "packet too short");
/* NB: ip_input() flips it into host endian XXX need more checking */
if (m->m_len >= sizeof(struct ip)) {
struct ip *ip = mtod(m, struct ip *);
if (ip->ip_off & htons(IP_MF | IP_OFFMASK))
goto done;
off = ip->ip_hl << 2;
nxt = ip->ip_p;
} else {
struct ip ih;
m_copydata(m, 0, sizeof(struct ip), &ih);
if (ih.ip_off & htons(IP_MF | IP_OFFMASK))
goto done;
off = ih.ip_hl << 2;
nxt = ih.ip_p;
}
while (off < m->m_pkthdr.len) {
struct ip6_ext ip6e;
struct tcphdr th;
struct udphdr uh;
struct icmp icmph;
switch (nxt) {
case IPPROTO_TCP:
spidx->ul_proto = nxt;
if (!needport)
goto done_proto;
if (off + sizeof(struct tcphdr) > m->m_pkthdr.len)
goto done;
m_copydata(m, off, sizeof(th), &th);
spidx->src.sin.sin_port = th.th_sport;
spidx->dst.sin.sin_port = th.th_dport;
return;
case IPPROTO_UDP:
spidx->ul_proto = nxt;
if (!needport)
goto done_proto;
if (off + sizeof(struct udphdr) > m->m_pkthdr.len)
goto done;
m_copydata(m, off, sizeof(uh), &uh);
spidx->src.sin.sin_port = uh.uh_sport;
spidx->dst.sin.sin_port = uh.uh_dport;
return;
case IPPROTO_AH:
if (off + sizeof(ip6e) > m->m_pkthdr.len)
goto done;
/* XXX sigh, this works but is totally bogus */
m_copydata(m, off, sizeof(ip6e), &ip6e);
off += (ip6e.ip6e_len + 2) << 2;
nxt = ip6e.ip6e_nxt;
break;
case IPPROTO_ICMP:
spidx->ul_proto = nxt;
if (off + sizeof(struct icmp) > m->m_pkthdr.len)
goto done;
m_copydata(m, off, sizeof(icmph), &icmph);
((struct sockaddr_in *)&spidx->src)->sin_port =
htons((uint16_t)icmph.icmp_type);
((struct sockaddr_in *)&spidx->dst)->sin_port =
htons((uint16_t)icmph.icmp_code);
return;
default:
/* XXX intermediate headers??? */
spidx->ul_proto = nxt;
goto done_proto;
}
}
done:
spidx->ul_proto = IPSEC_ULPROTO_ANY;
done_proto:
spidx->src.sin.sin_port = IPSEC_PORT_ANY;
spidx->dst.sin.sin_port = IPSEC_PORT_ANY;
}
static int
ipsec4_setspidx_ipaddr(struct mbuf *m, struct secpolicyindex *spidx)
{
static const struct sockaddr_in template = {
sizeof(struct sockaddr_in),
AF_INET,
0, { 0 }, { 0, 0, 0, 0, 0, 0, 0, 0 }
};
spidx->src.sin = template;
spidx->dst.sin = template;
if (m->m_len < sizeof(struct ip)) {
m_copydata(m, offsetof(struct ip, ip_src),
sizeof(struct in_addr), &spidx->src.sin.sin_addr);
m_copydata(m, offsetof(struct ip, ip_dst),
sizeof(struct in_addr), &spidx->dst.sin.sin_addr);
} else {
struct ip *ip = mtod(m, struct ip *);
spidx->src.sin.sin_addr = ip->ip_src;
spidx->dst.sin.sin_addr = ip->ip_dst;
}
spidx->prefs = sizeof(struct in_addr) << 3;
spidx->prefd = sizeof(struct in_addr) << 3;
return 0;
}
#ifdef INET6
static void
ipsec6_get_ulp(struct mbuf *m, struct secpolicyindex *spidx, int needport)
{
int off, nxt;
struct tcphdr th;
struct udphdr uh;
struct icmp6_hdr icmph;
KASSERT(m != NULL);
if (KEYDEBUG_ON(KEYDEBUG_IPSEC_DUMP)) {
kdebug_mbuf(__func__, m);
}
/* set default */
spidx->ul_proto = IPSEC_ULPROTO_ANY;
((struct sockaddr_in6 *)&spidx->src)->sin6_port = IPSEC_PORT_ANY;
((struct sockaddr_in6 *)&spidx->dst)->sin6_port = IPSEC_PORT_ANY;
nxt = -1;
off = ip6_lasthdr(m, 0, IPPROTO_IPV6, &nxt);
if (off < 0 || m->m_pkthdr.len < off)
return;
switch (nxt) {
case IPPROTO_TCP:
spidx->ul_proto = nxt;
if (!needport)
break;
if (off + sizeof(struct tcphdr) > m->m_pkthdr.len)
break;
m_copydata(m, off, sizeof(th), &th);
((struct sockaddr_in6 *)&spidx->src)->sin6_port = th.th_sport;
((struct sockaddr_in6 *)&spidx->dst)->sin6_port = th.th_dport;
break;
case IPPROTO_UDP:
spidx->ul_proto = nxt;
if (!needport)
break;
if (off + sizeof(struct udphdr) > m->m_pkthdr.len)
break;
m_copydata(m, off, sizeof(uh), &uh);
((struct sockaddr_in6 *)&spidx->src)->sin6_port = uh.uh_sport;
((struct sockaddr_in6 *)&spidx->dst)->sin6_port = uh.uh_dport;
break;
case IPPROTO_ICMPV6:
spidx->ul_proto = nxt;
if (off + sizeof(struct icmp6_hdr) > m->m_pkthdr.len)
break;
m_copydata(m, off, sizeof(icmph), &icmph);
((struct sockaddr_in6 *)&spidx->src)->sin6_port =
htons((uint16_t)icmph.icmp6_type);
((struct sockaddr_in6 *)&spidx->dst)->sin6_port =
htons((uint16_t)icmph.icmp6_code);
break;
default:
/* XXX intermediate headers??? */
spidx->ul_proto = nxt;
break;
}
}
static int
ipsec6_setspidx_ipaddr(struct mbuf *m, struct secpolicyindex *spidx)
{
struct ip6_hdr *ip6 = NULL;
struct ip6_hdr ip6buf;
struct sockaddr_in6 *sin6;
if (m->m_len >= sizeof(*ip6)) {
ip6 = mtod(m, struct ip6_hdr *);
} else {
m_copydata(m, 0, sizeof(ip6buf), &ip6buf);
ip6 = &ip6buf;
}
sin6 = (struct sockaddr_in6 *)&spidx->src;
memset(sin6, 0, sizeof(*sin6));
sin6->sin6_family = AF_INET6;
sin6->sin6_len = sizeof(struct sockaddr_in6);
memcpy(&sin6->sin6_addr, &ip6->ip6_src, sizeof(ip6->ip6_src));
if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) {
sin6->sin6_addr.s6_addr16[1] = 0;
sin6->sin6_scope_id = ntohs(ip6->ip6_src.s6_addr16[1]);
}
spidx->prefs = sizeof(struct in6_addr) << 3;
sin6 = (struct sockaddr_in6 *)&spidx->dst;
memset(sin6, 0, sizeof(*sin6));
sin6->sin6_family = AF_INET6;
sin6->sin6_len = sizeof(struct sockaddr_in6);
memcpy(&sin6->sin6_addr, &ip6->ip6_dst, sizeof(ip6->ip6_dst));
if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) {
sin6->sin6_addr.s6_addr16[1] = 0;
sin6->sin6_scope_id = ntohs(ip6->ip6_dst.s6_addr16[1]);
}
spidx->prefd = sizeof(struct in6_addr) << 3;
return 0;
}
#endif
static void
ipsec_delpcbpolicy(struct inpcbpolicy *p)
{
kmem_intr_free(p, sizeof(*p));
}
int
ipsec_init_pcbpolicy(struct socket *so, struct inpcbpolicy **policy)
{
struct inpcbpolicy *new;
KASSERT(so != NULL);
KASSERT(policy != NULL);
new = kmem_intr_zalloc(sizeof(*new), KM_NOSLEEP);
if (new == NULL) {
IPSECLOG(LOG_DEBUG, "No more memory.\n");
return ENOBUFS;
}
if (IPSEC_PRIVILEGED_SO(so))
new->priv = 1;
else
new->priv = 0;
/*
* Set dummy SPs. Actual SPs will be allocated later if needed.
*/
new->sp_in = &ipsec_dummy_sp;
new->sp_out = &ipsec_dummy_sp;
*policy = new;
return 0;
}
static void
ipsec_destroy_policy(struct secpolicy *sp)
{
if (sp == &ipsec_dummy_sp) {
; /* It's dummy. No need to free it. */
} else {
/*
* We cannot destroy here because it can be called in
* softint. So mark the SP as DEAD and let the timer
* destroy it. See key_timehandler_spd.
*/
sp->state = IPSEC_SPSTATE_DEAD;
}
}
int
ipsec_set_policy(struct inpcb *inp, const void *request, size_t len,
kauth_cred_t cred)
{
const struct sadb_x_policy *xpl;
struct secpolicy *newsp, *oldsp;
struct secpolicy **policy;
int error;
KASSERT(!cpu_softintr_p());
KASSERT(inp != NULL);
KASSERT(inp_locked(inp));
KASSERT(request != NULL);
if (len < sizeof(*xpl))
return EINVAL;
xpl = (const struct sadb_x_policy *)request;
KASSERT(inp->inp_sp != NULL);
/* select direction */
switch (xpl->sadb_x_policy_dir) {
case IPSEC_DIR_INBOUND:
policy = &inp->inp_sp->sp_in;
break;
case IPSEC_DIR_OUTBOUND:
policy = &inp->inp_sp->sp_out;
break;
default:
IPSECLOG(LOG_ERR, "invalid direction=%u\n",
xpl->sadb_x_policy_dir);
return EINVAL;
}
/* sanity check. */
if (policy == NULL || *policy == NULL)
return EINVAL;
if (KEYDEBUG_ON(KEYDEBUG_IPSEC_DUMP)) {
kdebug_sadb_xpolicy("set passed policy", request);
}
/* check policy type */
/* ipsec_set_policy() accepts IPSEC, ENTRUST and BYPASS. */
if (xpl->sadb_x_policy_type == IPSEC_POLICY_DISCARD ||
xpl->sadb_x_policy_type == IPSEC_POLICY_NONE)
return EINVAL;
/* check privileged socket */
if (xpl->sadb_x_policy_type == IPSEC_POLICY_BYPASS) {
error = kauth_authorize_network(cred, KAUTH_NETWORK_IPSEC,
KAUTH_REQ_NETWORK_IPSEC_BYPASS, NULL, NULL, NULL);
if (error)
return error;
}
/* allocation new SP entry */
if ((newsp = key_msg2sp(xpl, len, &error)) == NULL)
return error;
key_init_sp(newsp);
newsp->created = time_uptime;
/* Insert the global list for SPs for sockets */
key_socksplist_add(newsp);
/* clear old SP and set new SP */
oldsp = *policy;
*policy = newsp;
ipsec_destroy_policy(oldsp);
if (KEYDEBUG_ON(KEYDEBUG_IPSEC_DUMP)) {
printf("%s: new policy\n", __func__);
kdebug_secpolicy(newsp);
}
return 0;
}
int
ipsec_get_policy(struct inpcb *inp, const void *request, size_t len,
struct mbuf **mp)
{
const struct sadb_x_policy *xpl;
struct secpolicy *policy;
/* sanity check. */
if (inp == NULL || request == NULL || mp == NULL)
return EINVAL;
KASSERT(inp->inp_sp != NULL);
if (len < sizeof(*xpl))
return EINVAL;
xpl = (const struct sadb_x_policy *)request;
/* select direction */
switch (xpl->sadb_x_policy_dir) {
case IPSEC_DIR_INBOUND:
policy = inp->inp_sp->sp_in;
break;
case IPSEC_DIR_OUTBOUND:
policy = inp->inp_sp->sp_out;
break;
default:
IPSECLOG(LOG_ERR, "invalid direction=%u\n",
xpl->sadb_x_policy_dir);
return EINVAL;
}
if (policy == NULL)
return EINVAL;
*mp = key_sp2msg(policy, M_NOWAIT);
if (!*mp) {
IPSECLOG(LOG_DEBUG, "No more memory.\n");
return ENOBUFS;
}
if (KEYDEBUG_ON(KEYDEBUG_IPSEC_DUMP)) {
kdebug_mbuf(__func__, *mp);
}
return 0;
}
int
ipsec_delete_pcbpolicy(struct inpcb *inp)
{
KASSERT(inp != NULL);
if (inp->inp_sp == NULL)
return 0;
if (inp->inp_sp->sp_in != NULL)
ipsec_destroy_policy(inp->inp_sp->sp_in);
if (inp->inp_sp->sp_out != NULL)
ipsec_destroy_policy(inp->inp_sp->sp_out);
ipsec_invalpcbcache(inp->inp_sp, IPSEC_DIR_ANY);
ipsec_delpcbpolicy(inp->inp_sp);
inp->inp_sp = NULL;
return 0;
}
/*
* Return the current level (either IPSEC_LEVEL_USE or IPSEC_LEVEL_REQUIRE).
*/
u_int
ipsec_get_reqlevel(const struct ipsecrequest *isr)
{
u_int level = 0;
u_int esp_trans_deflev, esp_net_deflev;
u_int ah_trans_deflev, ah_net_deflev;
KASSERT(isr != NULL);
KASSERT(isr->sp != NULL);
KASSERTMSG(
isr->sp->spidx.src.sa.sa_family == isr->sp->spidx.dst.sa.sa_family,
"af family mismatch, src %u, dst %u",
isr->sp->spidx.src.sa.sa_family, isr->sp->spidx.dst.sa.sa_family);
/* XXX note that we have ipseclog() expanded here - code sync issue */
#define IPSEC_CHECK_DEFAULT(lev) \
(((lev) != IPSEC_LEVEL_USE && (lev) != IPSEC_LEVEL_REQUIRE \
&& (lev) != IPSEC_LEVEL_UNIQUE) ? \
(ipsec_debug ? log(LOG_INFO, "fixed system default level " #lev \
":%d->%d\n", (lev), IPSEC_LEVEL_REQUIRE) : (void)0), \
(lev) = IPSEC_LEVEL_REQUIRE, (lev) \
: (lev))
/* set default level */
switch (((struct sockaddr *)&isr->sp->spidx.src)->sa_family) {
#ifdef INET
case AF_INET:
esp_trans_deflev = IPSEC_CHECK_DEFAULT(ip4_esp_trans_deflev);
esp_net_deflev = IPSEC_CHECK_DEFAULT(ip4_esp_net_deflev);
ah_trans_deflev = IPSEC_CHECK_DEFAULT(ip4_ah_trans_deflev);
ah_net_deflev = IPSEC_CHECK_DEFAULT(ip4_ah_net_deflev);
break;
#endif
#ifdef INET6
case AF_INET6:
esp_trans_deflev = IPSEC_CHECK_DEFAULT(ip6_esp_trans_deflev);
esp_net_deflev = IPSEC_CHECK_DEFAULT(ip6_esp_net_deflev);
ah_trans_deflev = IPSEC_CHECK_DEFAULT(ip6_ah_trans_deflev);
ah_net_deflev = IPSEC_CHECK_DEFAULT(ip6_ah_net_deflev);
break;
#endif
default:
panic("%s: unknown af %u", __func__,
isr->sp->spidx.src.sa.sa_family);
}
#undef IPSEC_CHECK_DEFAULT
/* set level */
switch (isr->level) {
case IPSEC_LEVEL_DEFAULT:
switch (isr->saidx.proto) {
case IPPROTO_ESP:
if (isr->saidx.mode == IPSEC_MODE_TUNNEL)
level = esp_net_deflev;
else
level = esp_trans_deflev;
break;
case IPPROTO_AH:
if (isr->saidx.mode == IPSEC_MODE_TUNNEL)
level = ah_net_deflev;
else
level = ah_trans_deflev;
break;
case IPPROTO_IPCOMP:
/*
* we don't really care, as IPcomp document says that
* we shouldn't compress small packets
*/
level = IPSEC_LEVEL_USE;
break;
default:
panic("%s: Illegal protocol defined %u", __func__,
isr->saidx.proto);
}
break;
case IPSEC_LEVEL_USE:
case IPSEC_LEVEL_REQUIRE:
level = isr->level;
break;
case IPSEC_LEVEL_UNIQUE:
level = IPSEC_LEVEL_REQUIRE;
break;
default:
panic("%s: Illegal IPsec level %u", __func__, isr->level);
}
return level;
}
/*
* Check security policy requirements against the actual packet contents.
*
* If the SP requires an IPsec packet, and the packet was neither AH nor ESP,
* then kick it.
*/
static int
ipsec_sp_reject(const struct secpolicy *sp, const struct mbuf *m)
{
struct ipsecrequest *isr;
if (KEYDEBUG_ON(KEYDEBUG_IPSEC_DATA)) {
printf("%s: using SP\n", __func__);
kdebug_secpolicy(sp);
}
/* check policy */
switch (sp->policy) {
case IPSEC_POLICY_DISCARD:
return 1;
case IPSEC_POLICY_BYPASS:
case IPSEC_POLICY_NONE:
return 0;
}
KASSERTMSG(sp->policy == IPSEC_POLICY_IPSEC,
"invalid policy %u", sp->policy);
/* XXX should compare policy against ipsec header history */
for (isr = sp->req; isr != NULL; isr = isr->next) {
if (ipsec_get_reqlevel(isr) != IPSEC_LEVEL_REQUIRE)
continue;
switch (isr->saidx.proto) {
case IPPROTO_ESP:
if ((m->m_flags & M_DECRYPTED) == 0) {
KEYDEBUG_PRINTF(KEYDEBUG_IPSEC_DUMP,
"ESP m_flags:%x\n", m->m_flags);
return 1;
}
break;
case IPPROTO_AH:
if ((m->m_flags & M_AUTHIPHDR) == 0) {
KEYDEBUG_PRINTF(KEYDEBUG_IPSEC_DUMP,
"AH m_flags:%x\n", m->m_flags);
return 1;
}
break;
case IPPROTO_IPCOMP:
/*
* We don't really care, as IPcomp document
* says that we shouldn't compress small
* packets, IPComp policy should always be
* treated as being in "use" level.
*/
break;
}
}
return 0;
}
/*
* Check security policy requirements.
*/
int
ipsec_in_reject(struct mbuf *m, struct inpcb *inp)
{
struct secpolicy *sp;
int error;
int result;
KASSERT(m != NULL);
if (inp == NULL)
sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
IP_FORWARDING, &error);
else
sp = ipsec_getpolicybysock(m, IPSEC_DIR_INBOUND,
inp, &error);
if (sp != NULL) {
result = ipsec_sp_reject(sp, m);
if (result)
IPSEC_STATINC(IPSEC_STAT_IN_POLVIO);
KEY_SP_UNREF(&sp);
} else {
result = 0;
}
return result;
}
/*
* Compute the byte size to be occupied by the IPsec header. If it is
* tunneled, it includes the size of outer IP header.
*/
static size_t
ipsec_sp_hdrsiz(const struct secpolicy *sp, const struct mbuf *m)
{
struct ipsecrequest *isr;
size_t siz;
if (KEYDEBUG_ON(KEYDEBUG_IPSEC_DATA)) {
printf("%s: using SP\n", __func__);
kdebug_secpolicy(sp);
}
switch (sp->policy) {
case IPSEC_POLICY_DISCARD:
case IPSEC_POLICY_BYPASS:
case IPSEC_POLICY_NONE:
return 0;
}
KASSERTMSG(sp->policy == IPSEC_POLICY_IPSEC,
"invalid policy %u", sp->policy);
siz = 0;
for (isr = sp->req; isr != NULL; isr = isr->next) {
size_t clen = 0;
struct secasvar *sav;
switch (isr->saidx.proto) {
case IPPROTO_ESP:
sav = ipsec_lookup_sa(isr, m);
if (sav != NULL) {
clen = esp_hdrsiz(sav);
KEY_SA_UNREF(&sav);
} else
clen = esp_hdrsiz(NULL);
break;
case IPPROTO_AH:
sav = ipsec_lookup_sa(isr, m);
if (sav != NULL) {
clen = ah_hdrsiz(sav);
KEY_SA_UNREF(&sav);
} else
clen = ah_hdrsiz(NULL);
break;
case IPPROTO_IPCOMP:
clen = sizeof(struct ipcomp);
break;
}
if (isr->saidx.mode == IPSEC_MODE_TUNNEL) {
switch (isr->saidx.dst.sa.sa_family) {
case AF_INET:
clen += sizeof(struct ip);
break;
#ifdef INET6
case AF_INET6:
clen += sizeof(struct ip6_hdr);
break;
#endif
default:
IPSECLOG(LOG_ERR, "unknown AF %d in "
"IPsec tunnel SA\n",
((const struct sockaddr *)&isr->saidx.dst)
->sa_family);
break;
}
}
siz += clen;
}
return siz;
}
size_t
ipsec_hdrsiz(struct mbuf *m, u_int dir, struct inpcb *inp)
{
struct secpolicy *sp;
int error;
size_t size;
KASSERT(m != NULL);
KASSERTMSG(inp == NULL || inp->inp_socket != NULL,
"socket w/o inpcb");
if (inp == NULL)
sp = ipsec_getpolicybyaddr(m, dir, IP_FORWARDING, &error);
else
sp = ipsec_getpolicybysock(m, dir, inp, &error);
if (sp != NULL) {
size = ipsec_sp_hdrsiz(sp, m);
KEYDEBUG_PRINTF(KEYDEBUG_IPSEC_DATA, "size:%zu.\n", size);
KEY_SP_UNREF(&sp);
} else {
size = 0;
}
return size;
}
/*
* Check the variable replay window.
* ipsec_chkreplay() performs replay check before ICV verification.
* ipsec_updatereplay() updates replay bitmap. This must be called after
* ICV verification (it also performs replay check, which is usually done
* beforehand).
* 0 (zero) is returned if packet disallowed, 1 if packet permitted.
*
* based on RFC 2401.
*/
int
ipsec_chkreplay(u_int32_t seq, const struct secasvar *sav)
{
const struct secreplay *replay;
u_int32_t diff;
int fr;
u_int32_t wsizeb; /* constant: bits of window size */
int frlast; /* constant: last frame */
KASSERT(sav != NULL);
KASSERT(sav->replay != NULL);
replay = sav->replay;
if (replay->wsize == 0)
return 1; /* no need to check replay. */
/* constant */
frlast = replay->wsize - 1;
wsizeb = replay->wsize << 3;
/* sequence number of 0 is invalid */
if (seq == 0)
return 0;
/* first time is always okay */
if (replay->count == 0)
return 1;
if (seq > replay->lastseq) {
/* larger sequences are okay */
return 1;
} else {
/* seq is equal or less than lastseq. */
diff = replay->lastseq - seq;
/* over range to check, i.e. too old or wrapped */
if (diff >= wsizeb)
return 0;
fr = frlast - diff / 8;
/* this packet already seen ? */
if ((replay->bitmap)[fr] & (1 << (diff % 8)))
return 0;
/* out of order but good */
return 1;
}
}
/*
* check replay counter whether to update or not.
* OUT: 0: OK
* 1: NG
*/
int
ipsec_updatereplay(u_int32_t seq, const struct secasvar *sav)
{
struct secreplay *replay;
u_int32_t diff;
int fr;
u_int32_t wsizeb; /* constant: bits of window size */
int frlast; /* constant: last frame */
KASSERT(sav != NULL);
KASSERT(sav->replay != NULL);
replay = sav->replay;
if (replay->wsize == 0)
goto ok; /* no need to check replay. */
/* constant */
frlast = replay->wsize - 1;
wsizeb = replay->wsize << 3;
/* sequence number of 0 is invalid */
if (seq == 0)
return 1;
/* first time */
if (replay->count == 0) {
replay->lastseq = seq;
memset(replay->bitmap, 0, replay->wsize);
(replay->bitmap)[frlast] = 1;
goto ok;
}
if (seq > replay->lastseq) {
/* seq is larger than lastseq. */
diff = seq - replay->lastseq;
/* new larger sequence number */
if (diff < wsizeb) {
/* In window */
/* set bit for this packet */
vshiftl(replay->bitmap, diff, replay->wsize);
(replay->bitmap)[frlast] |= 1;
} else {
/* this packet has a "way larger" */
memset(replay->bitmap, 0, replay->wsize);
(replay->bitmap)[frlast] = 1;
}
replay->lastseq = seq;
/* larger is good */
} else {
/* seq is equal or less than lastseq. */
diff = replay->lastseq - seq;
/* over range to check, i.e. too old or wrapped */
if (diff >= wsizeb)
return 1;
fr = frlast - diff / 8;
/* this packet already seen ? */
if ((replay->bitmap)[fr] & (1 << (diff % 8)))
return 1;
/* mark as seen */
(replay->bitmap)[fr] |= (1 << (diff % 8));
/* out of order but good */
}
ok:
if (replay->count == ~0) {
char buf[IPSEC_LOGSASTRLEN];
/* set overflow flag */
replay->overflow++;
/* don't increment, no more packets accepted */
if ((sav->flags & SADB_X_EXT_CYCSEQ) == 0)
return 1;
IPSECLOG(LOG_WARNING, "replay counter made %d cycle. %s\n",
replay->overflow, ipsec_logsastr(sav, buf, sizeof(buf)));
}
replay->count++;
return 0;
}
/*
* shift variable length buffer to left.
* IN: bitmap: pointer to the buffer
* nbit: the number of to shift.
* wsize: buffer size (bytes).
*/
static void
vshiftl(unsigned char *bitmap, int nbit, int wsize)
{
int s, j, i;
unsigned char over;
for (j = 0; j < nbit; j += 8) {
s = (nbit - j < 8) ? (nbit - j): 8;
bitmap[0] <<= s;
for (i = 1; i < wsize; i++) {
over = (bitmap[i] >> (8 - s));
bitmap[i] <<= s;
bitmap[i-1] |= over;
}
}
return;
}
/* Return a printable string for the address. */
const char *
ipsec_address(const union sockaddr_union *sa, char *buf, size_t size)
{
switch (sa->sa.sa_family) {
case AF_INET:
in_print(buf, size, &sa->sin.sin_addr);
return buf;
#if INET6
case AF_INET6:
in6_print(buf, size, &sa->sin6.sin6_addr);
return buf;
#endif
default:
return "(unknown address family)";
}
}
const char *
ipsec_logsastr(const struct secasvar *sav, char *buf, size_t size)
{
const struct secasindex *saidx = &sav->sah->saidx;
char sbuf[IPSEC_ADDRSTRLEN], dbuf[IPSEC_ADDRSTRLEN];
KASSERTMSG(saidx->src.sa.sa_family == saidx->dst.sa.sa_family,
"af family mismatch, src %u, dst %u",
saidx->src.sa.sa_family, saidx->dst.sa.sa_family);
snprintf(buf, size, "SA(SPI=%u src=%s dst=%s)",
(u_int32_t)ntohl(sav->spi),
ipsec_address(&saidx->src, sbuf, sizeof(sbuf)),
ipsec_address(&saidx->dst, dbuf, sizeof(dbuf)));
return buf;
}
#ifdef INET6
struct secpolicy *
ipsec6_check_policy(struct mbuf *m, struct inpcb *inp, int flags,
int *needipsecp, int *errorp)
{
struct secpolicy *sp = NULL;
int error = 0;
int needipsec = 0;
if (ipsec_outdone(m)) {
goto skippolicycheck;
}
if (inp && ipsec_pcb_skip_ipsec(inp->inp_sp, IPSEC_DIR_OUTBOUND)) {
goto skippolicycheck;
}
sp = ipsec_checkpolicy(m, IPSEC_DIR_OUTBOUND, flags, &error, inp);
/*
* There are four return cases:
* sp != NULL apply IPsec policy
* sp == NULL, error == 0 no IPsec handling needed
* sp == NULL, error == -EINVAL discard packet w/o error
* sp == NULL, error != 0 discard packet, report error
*/
if (sp == NULL) {
needipsec = 0;
} else {
needipsec = 1;
}
skippolicycheck:
*errorp = error;
*needipsecp = needipsec;
return sp;
}
/*
* calculate UDP checksum for UDP encapsulated ESP for IPv6.
*
* RFC2460(Internet Protocol, Version 6 Specification) says:
*
* IPv6 receivers MUST discard UDP packets with a zero checksum.
*
* There is more relaxed specification RFC6935(IPv6 and UDP Checksums for
* Tunneled Packets). The document allows zero checksum. It's too
* late to publish, there are a lot of interoperability problems...
*/
void
ipsec6_udp_cksum(struct mbuf *m)
{
struct ip6_hdr *ip6;
uint16_t plen, uh_sum;
int off;
/* must called after m_pullup() */
KASSERT(m->m_len >= sizeof(struct ip6_hdr));
ip6 = mtod(m, struct ip6_hdr *);
KASSERT(ip6->ip6_nxt == IPPROTO_UDP);
/* ip6->ip6_plen can not be updated before ip6_output() */
plen = m->m_pkthdr.len - sizeof(*ip6);
KASSERT(plen >= sizeof(struct udphdr));
uh_sum = in6_cksum(m, IPPROTO_UDP, sizeof(*ip6), plen);
if (uh_sum == 0)
uh_sum = 0xffff;
off = sizeof(*ip6) + offsetof(struct udphdr, uh_sum);
m_copyback(m, off, sizeof(uh_sum), (void *)&uh_sum);
}
#endif /* INET6 */
/*
* -----------------------------------------------------------------------------
*/
/* XXX this stuff doesn't belong here... */
static struct xformsw *xforms = NULL;
/*
* Register a transform; typically at system startup.
*/
void
xform_register(struct xformsw *xsp)
{
xsp->xf_next = xforms;
xforms = xsp;
}
/*
* Initialize transform support in an sav.
*/
int
xform_init(struct secasvar *sav, int xftype)
{
struct xformsw *xsp;
if (sav->tdb_xform != NULL) /* previously initialized */
return 0;
for (xsp = xforms; xsp; xsp = xsp->xf_next)
if (xsp->xf_type == xftype)
return (*xsp->xf_init)(sav, xsp);
IPSECLOG(LOG_DEBUG, "no match for xform type %d\n", xftype);
return EINVAL;
}
/*
* XXXJRT This should be done as a protosw init call.
*/
void
ipsec_attach(void)
{
ipsec_output_init();
ipsecstat_percpu = percpu_alloc(sizeof(uint64_t) * IPSEC_NSTATS);
sysctl_net_inet_ipsec_setup(NULL);
#ifdef INET6
sysctl_net_inet6_ipsec6_setup(NULL);
#endif
ah_attach();
esp_attach();
ipcomp_attach();
ipe4_attach();
#ifdef TCP_SIGNATURE
tcpsignature_attach();
#endif
}
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