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strongswan/src/pluto/spdb.c

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/* Security Policy Data Base (such as it is)
* Copyright (C) 1998-2001 D. Hugh Redelmeier.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/queue.h>
#include <freeswan.h>
#include "constants.h"
#include "defs.h"
#include "id.h"
#include "connections.h"
#include "state.h"
#include "packet.h"
#include "keys.h"
#include "kernel.h"
#include "log.h"
#include "spdb.h"
#include "whack.h"
#include "crypto.h"
#include "alg_info.h"
#include "kernel_alg.h"
#include "ike_alg.h"
#include "db_ops.h"
#include "nat_traversal.h"
#define AD(x) x, countof(x) /* Array Description */
#define AD_NULL NULL, 0
/**************** Oakely (main mode) SA database ****************/
/* array of proposals to be conjoined (can only be one for Oakley) */
static struct db_prop oakley_pc[] =
{ { PROTO_ISAKMP, AD_NULL } };
/* array of proposal conjuncts (can only be one) */
static struct db_prop_conj oakley_props[] = { { AD(oakley_pc) } };
/* the sadb entry */
struct db_sa oakley_sadb = { AD(oakley_props) };
/**************** IPsec (quick mode) SA database ****************/
/* arrays of attributes for transforms */
static struct db_attr espsha1_attr[] = {
{ AUTH_ALGORITHM, AUTH_ALGORITHM_HMAC_SHA1 },
};
static struct db_attr ah_HMAC_SHA1_attr[] = {
{ AUTH_ALGORITHM, AUTH_ALGORITHM_HMAC_SHA1 },
};
/* arrays of transforms, each in in preference order */
static struct db_trans espa_trans[] = {
{ ESP_3DES, AD(espsha1_attr) },
};
static struct db_trans esp_trans[] = {
{ ESP_3DES, AD_NULL },
};
#ifdef SUPPORT_ESP_NULL
static struct db_trans espnull_trans[] = {
{ ESP_NULL, AD(espsha1_attr) },
};
#endif /* SUPPORT_ESP_NULL */
static struct db_trans ah_trans[] = {
{ AH_SHA, AD(ah_HMAC_SHA1_attr) },
};
static struct db_trans ipcomp_trans[] = {
{ IPCOMP_DEFLATE, AD_NULL },
};
/* arrays of proposals to be conjoined */
static struct db_prop ah_pc[] = {
{ PROTO_IPSEC_AH, AD(ah_trans) },
};
#ifdef SUPPORT_ESP_NULL
static struct db_prop espnull_pc[] = {
{ PROTO_IPSEC_ESP, AD(espnull_trans) },
};
#endif /* SUPPORT_ESP_NULL */
static struct db_prop esp_pc[] = {
{ PROTO_IPSEC_ESP, AD(espa_trans) },
};
static struct db_prop ah_esp_pc[] = {
{ PROTO_IPSEC_AH, AD(ah_trans) },
{ PROTO_IPSEC_ESP, AD(esp_trans) },
};
static struct db_prop compress_pc[] = {
{ PROTO_IPCOMP, AD(ipcomp_trans) },
};
static struct db_prop ah_compress_pc[] = {
{ PROTO_IPSEC_AH, AD(ah_trans) },
{ PROTO_IPCOMP, AD(ipcomp_trans) },
};
#ifdef SUPPORT_ESP_NULL
static struct db_prop espnull_compress_pc[] = {
{ PROTO_IPSEC_ESP, AD(espnull_trans) },
{ PROTO_IPCOMP, AD(ipcomp_trans) },
};
#endif /* SUPPORT_ESP_NULL */
static struct db_prop esp_compress_pc[] = {
{ PROTO_IPSEC_ESP, AD(espa_trans) },
{ PROTO_IPCOMP, AD(ipcomp_trans) },
};
static struct db_prop ah_esp_compress_pc[] = {
{ PROTO_IPSEC_AH, AD(ah_trans) },
{ PROTO_IPSEC_ESP, AD(esp_trans) },
{ PROTO_IPCOMP, AD(ipcomp_trans) },
};
/* arrays of proposal alternatives (each element is a conjunction) */
static struct db_prop_conj ah_props[] = {
{ AD(ah_pc) },
#ifdef SUPPORT_ESP_NULL
{ AD(espnull_pc) }
#endif
};
static struct db_prop_conj esp_props[] =
{ { AD(esp_pc) } };
static struct db_prop_conj ah_esp_props[] =
{ { AD(ah_esp_pc) } };
static struct db_prop_conj compress_props[] = {
{ AD(compress_pc) },
};
static struct db_prop_conj ah_compress_props[] = {
{ AD(ah_compress_pc) },
#ifdef SUPPORT_ESP_NULL
{ AD(espnull_compress_pc) }
#endif
};
static struct db_prop_conj esp_compress_props[] =
{ { AD(esp_compress_pc) } };
static struct db_prop_conj ah_esp_compress_props[] =
{ { AD(ah_esp_compress_pc) } };
/* The IPsec sadb is subscripted by a bitset (subset of policy)
* with members from { POLICY_ENCRYPT, POLICY_AUTHENTICATE, POLICY_COMPRESS }
* shifted right by POLICY_IPSEC_SHIFT.
*/
struct db_sa ipsec_sadb[1 << 3] = {
{ AD_NULL }, /* none */
{ AD(esp_props) }, /* POLICY_ENCRYPT */
{ AD(ah_props) }, /* POLICY_AUTHENTICATE */
{ AD(ah_esp_props) }, /* POLICY_ENCRYPT+POLICY_AUTHENTICATE */
{ AD(compress_props) }, /* POLICY_COMPRESS */
{ AD(esp_compress_props) }, /* POLICY_ENCRYPT+POLICY_COMPRESS */
{ AD(ah_compress_props) }, /* POLICY_AUTHENTICATE+POLICY_COMPRESS */
{ AD(ah_esp_compress_props) }, /* POLICY_ENCRYPT+POLICY_AUTHENTICATE+POLICY_COMPRESS */
};
#undef AD
#undef AD_NULL
/* output an attribute (within an SA) */
static bool
out_attr(int type
, unsigned long val
, struct_desc *attr_desc
, enum_names **attr_val_descs USED_BY_DEBUG
, pb_stream *pbs)
{
struct isakmp_attribute attr;
if (val >> 16 == 0)
{
/* short value: use TV form */
attr.isaat_af_type = type | ISAKMP_ATTR_AF_TV;
attr.isaat_lv = val;
if (!out_struct(&attr, attr_desc, pbs, NULL))
return FALSE;
}
else
{
/* This is a real fudge! Since we rarely use long attributes
* and since this is the only place where we can cause an
* ISAKMP message length to be other than a multiple of 4 octets,
* we force the length of the value to be a multiple of 4 octets.
* Furthermore, we only handle values up to 4 octets in length.
* Voila: a fixed format!
*/
pb_stream val_pbs;
u_int32_t nval = htonl(val);
attr.isaat_af_type = type | ISAKMP_ATTR_AF_TLV;
if (!out_struct(&attr, attr_desc, pbs, &val_pbs)
|| !out_raw(&nval, sizeof(nval), &val_pbs, "long attribute value"))
return FALSE;
close_output_pbs(&val_pbs);
}
DBG(DBG_EMITTING,
enum_names *d = attr_val_descs[type];
if (d != NULL)
DBG_log(" [%lu is %s]"
, val, enum_show(d, val)));
return TRUE;
}
#define return_on(var, val) do { var=val;goto return_out; } while(0);
/* Output an SA, as described by a db_sa.
* This has the side-effect of allocating SPIs for us.
*/
bool
out_sa(pb_stream *outs
, struct db_sa *sadb
, struct state *st
, bool oakley_mode
, u_int8_t np)
{
pb_stream sa_pbs;
int pcn;
bool ret = FALSE;
bool ah_spi_generated = FALSE
, esp_spi_generated = FALSE
, ipcomp_cpi_generated = FALSE;
#if !defined NO_KERNEL_ALG || !defined NO_IKE_ALG
struct db_context *db_ctx = NULL;
#endif
/* SA header out */
{
struct isakmp_sa sa;
sa.isasa_np = np;
st->st_doi = sa.isasa_doi = ISAKMP_DOI_IPSEC; /* all we know */
if (!out_struct(&sa, &isakmp_sa_desc, outs, &sa_pbs))
return_on(ret, FALSE);
}
/* within SA: situation out */
st->st_situation = SIT_IDENTITY_ONLY;
if (!out_struct(&st->st_situation, &ipsec_sit_desc, &sa_pbs, NULL))
return_on(ret, FALSE);
/* within SA: Proposal Payloads
*
* Multiple Proposals with the same number are simultaneous
* (conjuncts) and must deal with different protocols (AH or ESP).
* Proposals with different numbers are alternatives (disjuncts),
* in preference order.
* Proposal numbers must be monotonic.
* See RFC 2408 "ISAKMP" 4.2
*/
for (pcn = 0; pcn != sadb->prop_conj_cnt; pcn++)
{
struct db_prop_conj *pc = &sadb->prop_conjs[pcn];
int pn;
for (pn = 0; pn != pc->prop_cnt; pn++)
{
struct db_prop *p = &pc->props[pn];
pb_stream proposal_pbs;
struct isakmp_proposal proposal;
struct_desc *trans_desc = NULL;
struct_desc *attr_desc = NULL;
enum_names **attr_val_descs = NULL;
int tn;
bool tunnel_mode;
tunnel_mode = (pn == pc->prop_cnt-1)
&& (st->st_policy & POLICY_TUNNEL);
/* Proposal header */
proposal.isap_np = pcn == sadb->prop_conj_cnt-1 && pn == pc->prop_cnt-1
? ISAKMP_NEXT_NONE : ISAKMP_NEXT_P;
proposal.isap_proposal = pcn;
proposal.isap_protoid = p->protoid;
proposal.isap_spisize = oakley_mode ? 0
: p->protoid == PROTO_IPCOMP ? IPCOMP_CPI_SIZE
: IPSEC_DOI_SPI_SIZE;
/* In quick mode ONLY, create proposal for runtime kernel algos.
* Replace ESP proposals with runtime created one
*/
if (!oakley_mode && p->protoid == PROTO_IPSEC_ESP)
{
DBG(DBG_CONTROL | DBG_CRYPT,
if (st->st_connection->alg_info_esp)
{
static char buf[BUF_LEN]="";
alg_info_snprint(buf, sizeof (buf),
(struct alg_info *)st->st_connection->alg_info_esp);
DBG_log("esp proposal: %s", buf);
}
)
db_ctx = kernel_alg_db_new(st->st_connection->alg_info_esp, st->st_policy);
p = db_prop_get(db_ctx);
if (!p || p->trans_cnt == 0)
{
loglog(RC_LOG_SERIOUS,
"empty IPSEC SA proposal to send "
"(no kernel algorithms for esp selection)");
return_on(ret, FALSE);
}
}
if (oakley_mode && p->protoid == PROTO_ISAKMP)
{
DBG(DBG_CONTROL | DBG_CRYPT,
if (st->st_connection->alg_info_ike)
{
static char buf[BUF_LEN]="";
alg_info_snprint(buf, sizeof (buf),
(struct alg_info *)st->st_connection->alg_info_ike);
DBG_log("ike proposal: %s", buf);
}
)
db_ctx = ike_alg_db_new(st->st_connection, st->st_policy);
p = db_prop_get(db_ctx);
if (!p || p->trans_cnt == 0)
{
loglog(RC_LOG_SERIOUS,
"empty ISAKMP SA proposal to send "
"(no algorithms for ike selection?)");
return_on(ret, FALSE);
}
}
proposal.isap_notrans = p->trans_cnt;
if (!out_struct(&proposal, &isakmp_proposal_desc, &sa_pbs, &proposal_pbs))
return_on(ret, FALSE);
/* Per-protocols stuff:
* Set trans_desc.
* Set attr_desc.
* Set attr_val_descs.
* If not oakley_mode, emit SPI.
* We allocate SPIs on demand.
* All ESPs in an SA will share a single SPI.
* All AHs in an SAwill share a single SPI.
* AHs' SPI will be distinct from ESPs'.
* This latter is needed because KLIPS doesn't
* use the protocol when looking up a (dest, protocol, spi).
* ??? If multiple ESPs are composed, how should their SPIs
* be allocated?
*/
{
ipsec_spi_t *spi_ptr = NULL;
int proto = 0;
bool *spi_generated = NULL;
switch (p->protoid)
{
case PROTO_ISAKMP:
passert(oakley_mode);
trans_desc = &isakmp_isakmp_transform_desc;
attr_desc = &isakmp_oakley_attribute_desc;
attr_val_descs = oakley_attr_val_descs;
/* no SPI needed */
break;
case PROTO_IPSEC_AH:
passert(!oakley_mode);
trans_desc = &isakmp_ah_transform_desc;
attr_desc = &isakmp_ipsec_attribute_desc;
attr_val_descs = ipsec_attr_val_descs;
spi_ptr = &st->st_ah.our_spi;
spi_generated = &ah_spi_generated;
proto = IPPROTO_AH;
break;
case PROTO_IPSEC_ESP:
passert(!oakley_mode);
trans_desc = &isakmp_esp_transform_desc;
attr_desc = &isakmp_ipsec_attribute_desc;
attr_val_descs = ipsec_attr_val_descs;
spi_ptr = &st->st_esp.our_spi;
spi_generated = &esp_spi_generated;
proto = IPPROTO_ESP;
break;
case PROTO_IPCOMP:
passert(!oakley_mode);
trans_desc = &isakmp_ipcomp_transform_desc;
attr_desc = &isakmp_ipsec_attribute_desc;
attr_val_descs = ipsec_attr_val_descs;
/* a CPI isn't quite the same as an SPI
* so we use specialized code to emit it.
*/
if (!ipcomp_cpi_generated)
{
st->st_ipcomp.our_spi = get_my_cpi(
&st->st_connection->spd, tunnel_mode);
if (st->st_ipcomp.our_spi == 0)
return_on(ret, FALSE); /* problem generating CPI */
ipcomp_cpi_generated = TRUE;
}
/* CPI is stored in network low order end of an
* ipsec_spi_t. So we start a couple of bytes in.
*/
if (!out_raw((u_char *)&st->st_ipcomp.our_spi
+ IPSEC_DOI_SPI_SIZE - IPCOMP_CPI_SIZE
, IPCOMP_CPI_SIZE
, &proposal_pbs, "CPI"))
return_on(ret, FALSE);
break;
default:
bad_case(p->protoid);
}
if (spi_ptr != NULL)
{
if (!*spi_generated)
{
*spi_ptr = get_ipsec_spi(0
, proto
, &st->st_connection->spd
, tunnel_mode);
if (*spi_ptr == 0)
return FALSE;
*spi_generated = TRUE;
}
if (!out_raw((u_char *)spi_ptr, IPSEC_DOI_SPI_SIZE
, &proposal_pbs, "SPI"))
return_on(ret, FALSE);
}
}
/* within proposal: Transform Payloads */
for (tn = 0; tn != p->trans_cnt; tn++)
{
struct db_trans *t = &p->trans[tn];
pb_stream trans_pbs;
struct isakmp_transform trans;
int an;
trans.isat_np = (tn == p->trans_cnt - 1)
? ISAKMP_NEXT_NONE : ISAKMP_NEXT_T;
trans.isat_transnum = tn;
trans.isat_transid = t->transid;
if (!out_struct(&trans, trans_desc, &proposal_pbs, &trans_pbs))
return_on(ret, FALSE);
/* Within tranform: Attributes. */
/* For Phase 2 / Quick Mode, GROUP_DESCRIPTION is
* automatically generated because it must be the same
* in every transform. Except IPCOMP.
*/
if (p->protoid != PROTO_IPCOMP
&& st->st_pfs_group != NULL)
{
passert(!oakley_mode);
passert(st->st_pfs_group != &unset_group);
out_attr(GROUP_DESCRIPTION, st->st_pfs_group->algo_id
, attr_desc, attr_val_descs
, &trans_pbs);
}
/* automatically generate duration
* and, for Phase 2 / Quick Mode, encapsulation.
*/
if (oakley_mode)
{
out_attr(OAKLEY_LIFE_TYPE, OAKLEY_LIFE_SECONDS
, attr_desc, attr_val_descs
, &trans_pbs);
out_attr(OAKLEY_LIFE_DURATION
, st->st_connection->sa_ike_life_seconds
, attr_desc, attr_val_descs
, &trans_pbs);
}
else
{
/* RFC 2407 (IPSEC DOI) 4.5 specifies that
* the default is "unspecified (host-dependent)".
* This makes little sense, so we always specify it.
*
* Unlike other IPSEC transforms, IPCOMP defaults
* to Transport Mode, so we can exploit the default
* (draft-shacham-ippcp-rfc2393bis-05.txt 4.1).
*/
if (p->protoid != PROTO_IPCOMP
|| st->st_policy & POLICY_TUNNEL)
{
#ifndef I_KNOW_TRANSPORT_MODE_HAS_SECURITY_CONCERN_BUT_I_WANT_IT
if ((st->nat_traversal & NAT_T_DETECTED)
&& !(st->st_policy & POLICY_TUNNEL))
{
/* Inform user that we will not respect policy and only
* propose Tunnel Mode
*/
loglog(RC_LOG_SERIOUS, "NAT-Traversal: "
"Transport Mode not allowed due to security concerns -- "
"using Tunnel mode");
}
#endif
out_attr(ENCAPSULATION_MODE
#ifdef I_KNOW_TRANSPORT_MODE_HAS_SECURITY_CONCERN_BUT_I_WANT_IT
, NAT_T_ENCAPSULATION_MODE(st, st->st_policy)
#else
/* If NAT-T is detected, use UDP_TUNNEL as long as Transport
* Mode has security concerns.
*
* User has been informed of that
*/
, NAT_T_ENCAPSULATION_MODE(st, POLICY_TUNNEL)
#endif
, attr_desc, attr_val_descs
, &trans_pbs);
}
out_attr(SA_LIFE_TYPE, SA_LIFE_TYPE_SECONDS
, attr_desc, attr_val_descs
, &trans_pbs);
out_attr(SA_LIFE_DURATION
, st->st_connection->sa_ipsec_life_seconds
, attr_desc, attr_val_descs
, &trans_pbs);
}
/* spit out attributes from table */
for (an = 0; an != t->attr_cnt; an++)
{
struct db_attr *a = &t->attrs[an];
out_attr(a->type, a->val
, attr_desc, attr_val_descs
, &trans_pbs);
}
close_output_pbs(&trans_pbs);
}
close_output_pbs(&proposal_pbs);
}
/* end of a conjunction of proposals */
}
close_output_pbs(&sa_pbs);
ret = TRUE;
return_out:
#if !defined NO_KERNEL_ALG || !defined NO_IKE_ALG
if (db_ctx)
db_destroy(db_ctx);
#endif
return ret;
}
/* Handle long form of duration attribute.
* The code is can only handle values that can fit in unsigned long.
* "Clamping" is probably an acceptable way to impose this limitation.
*/
static u_int32_t
decode_long_duration(pb_stream *pbs)
{
u_int32_t val = 0;
/* ignore leading zeros */
while (pbs_left(pbs) != 0 && *pbs->cur == '\0')
pbs->cur++;
if (pbs_left(pbs) > sizeof(val))
{
/* "clamp" too large value to max representable value */
val -= 1; /* portable way to get to maximum value */
DBG(DBG_PARSING, DBG_log(" too large duration clamped to: %lu"
, (unsigned long)val));
}
else
{
/* decode number */
while (pbs_left(pbs) != 0)
val = (val << BITS_PER_BYTE) | *pbs->cur++;
DBG(DBG_PARSING, DBG_log(" long duration: %lu", (unsigned long)val));
}
return val;
}
/* Preparse the body of an ISAKMP SA Payload and
* return body of ISAKMP Proposal Payload
*
* Only IPsec DOI is accepted (what is the ISAKMP DOI?).
* Error response is rudimentary.
*/
notification_t
preparse_isakmp_sa_body(const struct isakmp_sa *sa
, pb_stream *sa_pbs
, u_int32_t *ipsecdoisit
, pb_stream *proposal_pbs
, struct isakmp_proposal *proposal)
{
/* DOI */
if (sa->isasa_doi != ISAKMP_DOI_IPSEC)
{
loglog(RC_LOG_SERIOUS, "Unknown/unsupported DOI %s", enum_show(&doi_names, sa->isasa_doi));
/* XXX Could send notification back */
return DOI_NOT_SUPPORTED;
}
/* Situation */
if (!in_struct(ipsecdoisit, &ipsec_sit_desc, sa_pbs, NULL))
return SITUATION_NOT_SUPPORTED;
if (*ipsecdoisit != SIT_IDENTITY_ONLY)
{
loglog(RC_LOG_SERIOUS, "unsupported IPsec DOI situation (%s)"
, bitnamesof(sit_bit_names, *ipsecdoisit));
/* XXX Could send notification back */
return SITUATION_NOT_SUPPORTED;
}
/* The rules for ISAKMP SAs are scattered.
* RFC 2409 "IKE" section 5 says that there
* can only be one SA, and it can have only one proposal in it.
* There may well be multiple transforms.
*/
if (!in_struct(proposal, &isakmp_proposal_desc, sa_pbs, proposal_pbs))
return PAYLOAD_MALFORMED;
if (proposal->isap_np != ISAKMP_NEXT_NONE)
{
loglog(RC_LOG_SERIOUS, "Proposal Payload must be alone in Oakley SA; found %s following Proposal"
, enum_show(&payload_names, proposal->isap_np));
return PAYLOAD_MALFORMED;
}
if (proposal->isap_protoid != PROTO_ISAKMP)
{
loglog(RC_LOG_SERIOUS, "unexpected Protocol ID (%s) found in Oakley Proposal"
, enum_show(&protocol_names, proposal->isap_protoid));
return INVALID_PROTOCOL_ID;
}
/* Just what should we accept for the SPI field?
* The RFC is sort of contradictory. We will ignore the SPI
* as long as it is of the proper size.
*
* From RFC2408 2.4 Identifying Security Associations:
* During phase 1 negotiations, the initiator and responder cookies
* determine the ISAKMP SA. Therefore, the SPI field in the Proposal
* payload is redundant and MAY be set to 0 or it MAY contain the
* transmitting entity's cookie.
*
* From RFC2408 3.5 Proposal Payload:
* o SPI Size (1 octet) - Length in octets of the SPI as defined by
* the Protocol-Id. In the case of ISAKMP, the Initiator and
* Responder cookie pair from the ISAKMP Header is the ISAKMP SPI,
* therefore, the SPI Size is irrelevant and MAY be from zero (0) to
* sixteen (16). If the SPI Size is non-zero, the content of the
* SPI field MUST be ignored. If the SPI Size is not a multiple of
* 4 octets it will have some impact on the SPI field and the
* alignment of all payloads in the message. The Domain of
* Interpretation (DOI) will dictate the SPI Size for other
* protocols.
*/
if (proposal->isap_spisize == 0)
{
/* empty (0) SPI -- fine */
}
else if (proposal->isap_spisize <= MAX_ISAKMP_SPI_SIZE)
{
u_char junk_spi[MAX_ISAKMP_SPI_SIZE];
if (!in_raw(junk_spi, proposal->isap_spisize, proposal_pbs, "Oakley SPI"))
return PAYLOAD_MALFORMED;
}
else
{
loglog(RC_LOG_SERIOUS, "invalid SPI size (%u) in Oakley Proposal"
, (unsigned)proposal->isap_spisize);
return INVALID_SPI;
}
return NOTHING_WRONG;
}
static struct {
u_int8_t *start;
u_int8_t *cur;
u_int8_t *roof;
} backup;
/*
* backup the pointer into a pb_stream
*/
void
backup_pbs(pb_stream *pbs)
{
backup.start = pbs->start;
backup.cur = pbs->cur;
backup.roof = pbs->roof;
}
/*
* restore the pointer into a pb_stream
*/
void
restore_pbs(pb_stream *pbs)
{
pbs->start = backup.start;
pbs->cur = backup.cur;
pbs->roof = backup.roof;
}
/*
* Parse an ISAKMP Proposal Payload for RSA and PSK authentication policies
*/
notification_t
parse_isakmp_policy(pb_stream *proposal_pbs
, u_int notrans
, lset_t *policy)
{
int last_transnum = -1;
*policy = LEMPTY;
while (notrans--)
{
pb_stream trans_pbs;
u_char *attr_start;
size_t attr_len;
struct isakmp_transform trans;
if (!in_struct(&trans, &isakmp_isakmp_transform_desc, proposal_pbs, &trans_pbs))
return BAD_PROPOSAL_SYNTAX;
if (trans.isat_transnum <= last_transnum)
{
/* picky, picky, picky */
loglog(RC_LOG_SERIOUS, "Transform Numbers are not monotonically increasing"
" in Oakley Proposal");
return BAD_PROPOSAL_SYNTAX;
}
last_transnum = trans.isat_transnum;
if (trans.isat_transid != KEY_IKE)
{
loglog(RC_LOG_SERIOUS, "expected KEY_IKE but found %s in Oakley Transform"
, enum_show(&isakmp_transformid_names, trans.isat_transid));
return INVALID_TRANSFORM_ID;
}
attr_start = trans_pbs.cur;
attr_len = pbs_left(&trans_pbs);
/* preprocess authentication attributes only */
while (pbs_left(&trans_pbs) != 0)
{
struct isakmp_attribute a;
pb_stream attr_pbs;
if (!in_struct(&a, &isakmp_oakley_attribute_desc, &trans_pbs, &attr_pbs))
return BAD_PROPOSAL_SYNTAX;
passert((a.isaat_af_type & ISAKMP_ATTR_RTYPE_MASK) < 32);
switch (a.isaat_af_type)
{
case OAKLEY_AUTHENTICATION_METHOD | ISAKMP_ATTR_AF_TV:
switch (a.isaat_lv)
{
case OAKLEY_PRESHARED_KEY:
*policy |= POLICY_PSK;
break;
case OAKLEY_RSA_SIG:
case OAKLEY_ECDSA_256:
case OAKLEY_ECDSA_384:
case OAKLEY_ECDSA_521:
*policy |= POLICY_PUBKEY;
break;
case XAUTHInitPreShared:
*policy |= POLICY_XAUTH_SERVER;
/* fall through */
case XAUTHRespPreShared:
*policy |= POLICY_XAUTH_PSK;
break;
case XAUTHInitRSA:
*policy |= POLICY_XAUTH_SERVER;
/* fall through */
case XAUTHRespRSA:
*policy |= POLICY_XAUTH_RSASIG;
break;
default:
break;
}
break;
default:
break;
}
}
}
DBG(DBG_CONTROL|DBG_PARSING,
DBG_log("preparse_isakmp_policy: peer requests %s authentication"
, prettypolicy(*policy))
)
return NOTHING_WRONG;
}
/*
* check that we can find a preshared secret
*/
static err_t
find_preshared_key(struct state* st)
{
err_t ugh = NULL;
struct connection *c = st->st_connection;
if (get_preshared_secret(c) == NULL)
{
char my_id[BUF_LEN], his_id[BUF_LEN];
idtoa(&c->spd.this.id, my_id, sizeof(my_id));
if (his_id_was_instantiated(c))
strcpy(his_id, "%any");
else
idtoa(&c->spd.that.id, his_id, sizeof(his_id));
ugh = builddiag("Can't authenticate: no preshared key found for `%s' and `%s'"
, my_id, his_id);
}
return ugh;
}
/* Parse the body of an ISAKMP SA Payload (i.e. Phase 1 / Main Mode).
* Various shortcuts are taken. In particular, the policy, such as
* it is, is hardwired.
*
* If r_sa is non-NULL, the body of an SA representing the selected
* proposal is emitted.
*
* This routine is used by main_inI1_outR1() and main_inR1_outI2().
*/
notification_t
parse_isakmp_sa_body(u_int32_t ipsecdoisit
, pb_stream *proposal_pbs
, struct isakmp_proposal *proposal
, pb_stream *r_sa_pbs
, struct state *st
, bool initiator)
{
struct connection *c = st->st_connection;
unsigned no_trans_left;
/* for each transform payload... */
no_trans_left = proposal->isap_notrans;
for (;;)
{
pb_stream trans_pbs;
u_char *attr_start;
size_t attr_len;
struct isakmp_transform trans;
lset_t seen_attrs = 0;
lset_t seen_durations = 0;
u_int16_t life_type = 0;
struct oakley_trans_attrs ta;
err_t ugh = NULL; /* set to diagnostic when problem detected */
/* initialize only optional field in ta */
ta.life_seconds = OAKLEY_ISAKMP_SA_LIFETIME_DEFAULT; /* When this SA expires (seconds) */
if (no_trans_left == 0)
{
loglog(RC_LOG_SERIOUS, "number of Transform Payloads disagrees with Oakley Proposal Payload");
return BAD_PROPOSAL_SYNTAX;
}
in_struct(&trans, &isakmp_isakmp_transform_desc, proposal_pbs, &trans_pbs);
attr_start = trans_pbs.cur;
attr_len = pbs_left(&trans_pbs);
/* process all the attributes that make up the transform */
while (pbs_left(&trans_pbs) != 0)
{
struct isakmp_attribute a;
pb_stream attr_pbs;
u_int32_t val; /* room for larger values */
if (!in_struct(&a, &isakmp_oakley_attribute_desc, &trans_pbs, &attr_pbs))
return BAD_PROPOSAL_SYNTAX;
passert((a.isaat_af_type & ISAKMP_ATTR_RTYPE_MASK) < 32);
if (LHAS(seen_attrs, a.isaat_af_type & ISAKMP_ATTR_RTYPE_MASK))
{
loglog(RC_LOG_SERIOUS, "repeated %s attribute in Oakley Transform %u"
, enum_show(&oakley_attr_names, a.isaat_af_type)
, trans.isat_transnum);
return BAD_PROPOSAL_SYNTAX;
}
seen_attrs |= LELEM(a.isaat_af_type & ISAKMP_ATTR_RTYPE_MASK);
val = a.isaat_lv;
DBG(DBG_PARSING,
{
enum_names *vdesc = oakley_attr_val_descs
[a.isaat_af_type & ISAKMP_ATTR_RTYPE_MASK];
if (vdesc != NULL)
{
const char *nm = enum_name(vdesc, val);
if (nm != NULL)
DBG_log(" [%u is %s]", (unsigned)val, nm);
}
});
switch (a.isaat_af_type)
{
case OAKLEY_ENCRYPTION_ALGORITHM | ISAKMP_ATTR_AF_TV:
if (ike_alg_get_crypter(val))
{
ta.encrypt = val;
ta.encrypter = ike_alg_get_crypter(val);
ta.enckeylen = ta.encrypter->keydeflen;
}
else
{
ugh = builddiag("%s is not supported"
, enum_show(&oakley_enc_names, val));
}
break;
case OAKLEY_HASH_ALGORITHM | ISAKMP_ATTR_AF_TV:
if (ike_alg_get_hasher(val))
{
ta.hash = val;
ta.hasher = ike_alg_get_hasher(val);
}
else
{
ugh = builddiag("%s is not supported"
, enum_show(&oakley_hash_names, val));
}
break;
case OAKLEY_AUTHENTICATION_METHOD | ISAKMP_ATTR_AF_TV:
{
/* check that authentication method is acceptable */
lset_t iap = st->st_policy & POLICY_ID_AUTH_MASK;
/* is the initiator the XAUTH client? */
bool xauth_init = ( initiator && (st->st_policy & POLICY_XAUTH_SERVER) == LEMPTY)
|| (!initiator && (st->st_policy & POLICY_XAUTH_SERVER) != LEMPTY);
switch (val)
{
case OAKLEY_PRESHARED_KEY:
if ((iap & POLICY_PSK) == LEMPTY)
{
ugh = "policy does not allow pre-shared key authentication";
}
else
{
ugh = find_preshared_key(st);
ta.auth = OAKLEY_PRESHARED_KEY;
}
break;
case XAUTHInitPreShared:
if ((iap & POLICY_XAUTH_PSK) == LEMPTY || !xauth_init)
{
ugh = "policy does not allow XAUTHInitPreShared authentication";
}
else
{
ugh = find_preshared_key(st);
ta.auth = XAUTHInitPreShared;
}
break;
case XAUTHRespPreShared:
if ((iap & POLICY_XAUTH_PSK) == LEMPTY || xauth_init)
{
ugh = "policy does not allow XAUTHRespPreShared authentication";
}
else
{
ugh = find_preshared_key(st);
ta.auth = XAUTHRespPreShared;
}
break;
case OAKLEY_RSA_SIG:
case OAKLEY_ECDSA_256:
case OAKLEY_ECDSA_384:
case OAKLEY_ECDSA_521:
if ((iap & POLICY_PUBKEY) == LEMPTY)
{
ugh = "policy does not allow public key authentication";
}
else
{
ta.auth = val;
}
break;
case XAUTHInitRSA:
if ((iap & POLICY_XAUTH_RSASIG) == LEMPTY || !xauth_init)
{
ugh = "policy does not allow XAUTHInitRSA authentication";
}
else
{
ta.auth = XAUTHInitRSA;
}
break;
case XAUTHRespRSA:
if ((iap & POLICY_XAUTH_RSASIG) == LEMPTY || xauth_init)
{
ugh = "policy does not allow XAUTHRespRSA authentication";
}
else
{
ta.auth = XAUTHRespRSA;
}
break;
default:
ugh = builddiag("Pluto does not support %s authentication"
, enum_show(&oakley_auth_names, val));
break;
}
}
break;
case OAKLEY_GROUP_DESCRIPTION | ISAKMP_ATTR_AF_TV:
ta.group = ike_alg_get_dh_group(val);
if (ta.group == NULL)
{
ugh = builddiag("%s is not supported"
, enum_show(&oakley_group_names, val));
}
break;
case OAKLEY_LIFE_TYPE | ISAKMP_ATTR_AF_TV:
switch (val)
{
case OAKLEY_LIFE_SECONDS:
case OAKLEY_LIFE_KILOBYTES:
if (LHAS(seen_durations, val))
{
loglog(RC_LOG_SERIOUS
, "attribute OAKLEY_LIFE_TYPE value %s repeated"
, enum_show(&oakley_lifetime_names, val));
return BAD_PROPOSAL_SYNTAX;
}
seen_durations |= LELEM(val);
life_type = val;
break;
default:
ugh = builddiag("unknown value %s"
, enum_show(&oakley_lifetime_names, val));
break;
}
break;
case OAKLEY_LIFE_DURATION | ISAKMP_ATTR_AF_TLV:
val = decode_long_duration(&attr_pbs);
/* fall through */
case OAKLEY_LIFE_DURATION | ISAKMP_ATTR_AF_TV:
if (!LHAS(seen_attrs, OAKLEY_LIFE_TYPE))
{
ugh = "OAKLEY_LIFE_DURATION attribute not preceded by OAKLEY_LIFE_TYPE attribute";
break;
}
seen_attrs &= ~(LELEM(OAKLEY_LIFE_DURATION) | LELEM(OAKLEY_LIFE_TYPE));
switch (life_type)
{
case OAKLEY_LIFE_SECONDS:
if (val > OAKLEY_ISAKMP_SA_LIFETIME_MAXIMUM)
{
#ifdef CISCO_QUIRKS
plog("peer requested %lu seconds"
" which exceeds our limit %d seconds"
, (long) val
, OAKLEY_ISAKMP_SA_LIFETIME_MAXIMUM);
plog("lifetime reduced to %d seconds "
"(todo: IPSEC_RESPONDER_LIFETIME notification)"
, OAKLEY_ISAKMP_SA_LIFETIME_MAXIMUM);
val = OAKLEY_ISAKMP_SA_LIFETIME_MAXIMUM;
#else
ugh = builddiag("peer requested %lu seconds"
" which exceeds our limit %d seconds"
, (long) val
, OAKLEY_ISAKMP_SA_LIFETIME_MAXIMUM);
#endif
}
ta.life_seconds = val;
break;
case OAKLEY_LIFE_KILOBYTES:
ta.life_kilobytes = val;
break;
default:
bad_case(life_type);
}
break;
case OAKLEY_KEY_LENGTH | ISAKMP_ATTR_AF_TV:
if ((seen_attrs & LELEM(OAKLEY_ENCRYPTION_ALGORITHM)) == 0)
{
ugh = "OAKLEY_KEY_LENGTH attribute not preceded by "
"OAKLEY_ENCRYPTION_ALGORITHM attribute";
break;
}
if (ta.encrypter == NULL)
{
ugh = "NULL encrypter with seen OAKLEY_ENCRYPTION_ALGORITHM";
break;
}
/*
* check if this keylen is compatible with specified algorithm
*/
if (val
&& (val < ta.encrypter->keyminlen || val > ta.encrypter->keymaxlen))
{
ugh = "peer proposed key length not valid for "
"encryption algorithm specified";
}
ta.enckeylen = val;
break;
#if 0 /* not yet supported */
case OAKLEY_GROUP_TYPE | ISAKMP_ATTR_AF_TV:
case OAKLEY_PRF | ISAKMP_ATTR_AF_TV:
case OAKLEY_FIELD_SIZE | ISAKMP_ATTR_AF_TV:
case OAKLEY_GROUP_PRIME | ISAKMP_ATTR_AF_TV:
case OAKLEY_GROUP_PRIME | ISAKMP_ATTR_AF_TLV:
case OAKLEY_GROUP_GENERATOR_ONE | ISAKMP_ATTR_AF_TV:
case OAKLEY_GROUP_GENERATOR_ONE | ISAKMP_ATTR_AF_TLV:
case OAKLEY_GROUP_GENERATOR_TWO | ISAKMP_ATTR_AF_TV:
case OAKLEY_GROUP_GENERATOR_TWO | ISAKMP_ATTR_AF_TLV:
case OAKLEY_GROUP_CURVE_A | ISAKMP_ATTR_AF_TV:
case OAKLEY_GROUP_CURVE_A | ISAKMP_ATTR_AF_TLV:
case OAKLEY_GROUP_CURVE_B | ISAKMP_ATTR_AF_TV:
case OAKLEY_GROUP_CURVE_B | ISAKMP_ATTR_AF_TLV:
case OAKLEY_GROUP_ORDER | ISAKMP_ATTR_AF_TV:
case OAKLEY_GROUP_ORDER | ISAKMP_ATTR_AF_TLV:
#endif
default:
/* fix compiler warning */
memset(&ta, 0, sizeof(ta));
ugh = "unsupported OAKLEY attribute";
break;
}
if (ugh != NULL)
{
loglog(RC_LOG_SERIOUS, "%s. Attribute %s"
, ugh, enum_show(&oakley_attr_names, a.isaat_af_type));
break;
}
}
/*
* ML: at last check for allowed transforms in alg_info_ike
* (ALG_INFO_F_STRICT flag)
*/
if (ugh == NULL)
{
if (!ike_alg_ok_final(ta.encrypt, ta.enckeylen, ta.hash,
ta.group ? ta.group->algo_id : -1, c->alg_info_ike))
{
ugh = "OAKLEY proposal refused";
}
}
if (ugh == NULL)
{
/* a little more checking is in order */
{
lset_t missing
= ~seen_attrs
& (LELEM(OAKLEY_ENCRYPTION_ALGORITHM)
| LELEM(OAKLEY_HASH_ALGORITHM)
| LELEM(OAKLEY_AUTHENTICATION_METHOD)
| LELEM(OAKLEY_GROUP_DESCRIPTION));
if (missing)
{
loglog(RC_LOG_SERIOUS, "missing mandatory attribute(s) %s in Oakley Transform %u"
, bitnamesof(oakley_attr_bit_names, missing)
, trans.isat_transnum);
return BAD_PROPOSAL_SYNTAX;
}
}
/* We must have liked this transform.
* Lets finish early and leave.
*/
DBG(DBG_PARSING | DBG_CRYPT
, DBG_log("Oakley Transform %u accepted", trans.isat_transnum));
if (r_sa_pbs != NULL)
{
struct isakmp_proposal r_proposal = *proposal;
pb_stream r_proposal_pbs;
struct isakmp_transform r_trans = trans;
pb_stream r_trans_pbs;
/* Situation */
if (!out_struct(&ipsecdoisit, &ipsec_sit_desc, r_sa_pbs, NULL))
impossible();
/* Proposal */
#ifdef EMIT_ISAKMP_SPI
r_proposal.isap_spisize = COOKIE_SIZE;
#else
r_proposal.isap_spisize = 0;
#endif
r_proposal.isap_notrans = 1;
if (!out_struct(&r_proposal, &isakmp_proposal_desc, r_sa_pbs, &r_proposal_pbs))
impossible();
/* SPI */
#ifdef EMIT_ISAKMP_SPI
if (!out_raw(my_cookie, COOKIE_SIZE, &r_proposal_pbs, "SPI"))
impossible();
r_proposal.isap_spisize = COOKIE_SIZE;
#else
/* none (0) */
#endif
/* Transform */
r_trans.isat_np = ISAKMP_NEXT_NONE;
if (!out_struct(&r_trans, &isakmp_isakmp_transform_desc, &r_proposal_pbs, &r_trans_pbs))
impossible();
if (!out_raw(attr_start, attr_len, &r_trans_pbs, "attributes"))
impossible();
close_output_pbs(&r_trans_pbs);
close_output_pbs(&r_proposal_pbs);
close_output_pbs(r_sa_pbs);
}
/* copy over the results */
st->st_oakley = ta;
return NOTHING_WRONG;
}
/* on to next transform */
no_trans_left--;
if (trans.isat_np == ISAKMP_NEXT_NONE)
{
if (no_trans_left != 0)
{
loglog(RC_LOG_SERIOUS, "number of Transform Payloads disagrees with Oakley Proposal Payload");
return BAD_PROPOSAL_SYNTAX;
}
break;
}
if (trans.isat_np != ISAKMP_NEXT_T)
{
loglog(RC_LOG_SERIOUS, "unexpected %s payload in Oakley Proposal"
, enum_show(&payload_names, proposal->isap_np));
return BAD_PROPOSAL_SYNTAX;
}
}
loglog(RC_LOG_SERIOUS, "no acceptable Oakley Transform");
return NO_PROPOSAL_CHOSEN;
}
/* Parse the body of an IPsec SA Payload (i.e. Phase 2 / Quick Mode).
*
* The main routine is parse_ipsec_sa_body; other functions defined
* between here and there are just helpers.
*
* Various shortcuts are taken. In particular, the policy, such as
* it is, is hardwired.
*
* If r_sa is non-NULL, the body of an SA representing the selected
* proposal is emitted into it.
*
* If "selection" is true, the SA is supposed to represent the
* single tranform that the peer has accepted.
* ??? We only check that it is acceptable, not that it is one that we offered!
*
* Only IPsec DOI is accepted (what is the ISAKMP DOI?).
* Error response is rudimentary.
*
* Since all ISAKMP groups in all SA Payloads must match, st->st_pfs_group
* holds this across multiple payloads.
* &unset_group signifies not yet "set"; NULL signifies NONE.
*
* This routine is used by quick_inI1_outR1() and quick_inR1_outI2().
*/
static const struct ipsec_trans_attrs null_ipsec_trans_attrs = {
0, /* transid (NULL, for now) */
0, /* spi */
SA_LIFE_DURATION_DEFAULT, /* life_seconds */
SA_LIFE_DURATION_K_DEFAULT, /* life_kilobytes */
ENCAPSULATION_MODE_UNSPECIFIED, /* encapsulation */
AUTH_ALGORITHM_NONE, /* auth */
0, /* key_len */
0, /* key_rounds */
};
static bool
parse_ipsec_transform(struct isakmp_transform *trans
, struct ipsec_trans_attrs *attrs
, pb_stream *prop_pbs
, pb_stream *trans_pbs
, struct_desc *trans_desc
, int previous_transnum /* or -1 if none */
, bool selection
, bool is_last
, bool is_ipcomp
, struct state *st) /* current state object */
{
lset_t seen_attrs = 0;
lset_t seen_durations = 0;
u_int16_t life_type = 0;
const struct dh_desc *pfs_group = NULL;
if (!in_struct(trans, trans_desc, prop_pbs, trans_pbs))
return FALSE;
if (trans->isat_transnum <= previous_transnum)
{
loglog(RC_LOG_SERIOUS, "Transform Numbers in Proposal are not monotonically increasing");
return FALSE;
}
switch (trans->isat_np)
{
case ISAKMP_NEXT_T:
if (is_last)
{
loglog(RC_LOG_SERIOUS, "Proposal Payload has more Transforms than specified");
return FALSE;
}
break;
case ISAKMP_NEXT_NONE:
if (!is_last)
{
loglog(RC_LOG_SERIOUS, "Proposal Payload has fewer Transforms than specified");
return FALSE;
}
break;
default:
loglog(RC_LOG_SERIOUS, "expecting Transform Payload, but found %s in Proposal"
, enum_show(&payload_names, trans->isat_np));
return FALSE;
}
*attrs = null_ipsec_trans_attrs;
attrs->transid = trans->isat_transid;
while (pbs_left(trans_pbs) != 0)
{
struct isakmp_attribute a;
pb_stream attr_pbs;
enum_names *vdesc;
u_int32_t val; /* room for larger value */
bool ipcomp_inappropriate = is_ipcomp; /* will get reset if OK */
if (!in_struct(&a, &isakmp_ipsec_attribute_desc, trans_pbs, &attr_pbs))
return FALSE;
passert((a.isaat_af_type & ISAKMP_ATTR_RTYPE_MASK) < 32);
if (LHAS(seen_attrs, a.isaat_af_type & ISAKMP_ATTR_RTYPE_MASK))
{
loglog(RC_LOG_SERIOUS, "repeated %s attribute in IPsec Transform %u"
, enum_show(&ipsec_attr_names, a.isaat_af_type)
, trans->isat_transnum);
return FALSE;
}
seen_attrs |= LELEM(a.isaat_af_type & ISAKMP_ATTR_RTYPE_MASK);
val = a.isaat_lv;
vdesc = ipsec_attr_val_descs[a.isaat_af_type & ISAKMP_ATTR_RTYPE_MASK];
if (vdesc != NULL)
{
if (enum_name(vdesc, val) == NULL)
{
loglog(RC_LOG_SERIOUS, "invalid value %u for attribute %s in IPsec Transform"
, (unsigned)val, enum_show(&ipsec_attr_names, a.isaat_af_type));
return FALSE;
}
DBG(DBG_PARSING
, if ((a.isaat_af_type & ISAKMP_ATTR_AF_MASK) == ISAKMP_ATTR_AF_TV)
DBG_log(" [%u is %s]"
, (unsigned)val, enum_show(vdesc, val)));
}
switch (a.isaat_af_type)
{
case SA_LIFE_TYPE | ISAKMP_ATTR_AF_TV:
ipcomp_inappropriate = FALSE;
if (LHAS(seen_durations, val))
{
loglog(RC_LOG_SERIOUS, "attribute SA_LIFE_TYPE value %s repeated in message"
, enum_show(&sa_lifetime_names, val));
return FALSE;
}
seen_durations |= LELEM(val);
life_type = val;
break;
case SA_LIFE_DURATION | ISAKMP_ATTR_AF_TLV:
val = decode_long_duration(&attr_pbs);
/* fall through */
case SA_LIFE_DURATION | ISAKMP_ATTR_AF_TV:
ipcomp_inappropriate = FALSE;
if (!LHAS(seen_attrs, SA_LIFE_DURATION))
{
loglog(RC_LOG_SERIOUS, "SA_LIFE_DURATION IPsec attribute not preceded by SA_LIFE_TYPE attribute");
return FALSE;
}
seen_attrs &= ~(LELEM(SA_LIFE_DURATION) | LELEM(SA_LIFE_TYPE));
switch (life_type)
{
case SA_LIFE_TYPE_SECONDS:
/* silently limit duration to our maximum */
attrs->life_seconds = val <= SA_LIFE_DURATION_MAXIMUM
? val : SA_LIFE_DURATION_MAXIMUM;
break;
case SA_LIFE_TYPE_KBYTES:
attrs->life_kilobytes = val;
break;
default:
bad_case(life_type);
}
break;
case GROUP_DESCRIPTION | ISAKMP_ATTR_AF_TV:
if (is_ipcomp)
{
/* Accept reluctantly. Should not happen, according to
* draft-shacham-ippcp-rfc2393bis-05.txt 4.1.
*/
ipcomp_inappropriate = FALSE;
loglog(RC_COMMENT
, "IPCA (IPcomp SA) contains GROUP_DESCRIPTION."
" Ignoring inapproprate attribute.");
}
pfs_group = ike_alg_get_dh_group(val);
if (pfs_group == NULL)
{
loglog(RC_LOG_SERIOUS, "only OAKLEY_GROUP_MODP1024 and OAKLEY_GROUP_MODP1536 supported for PFS");
return FALSE;
}
break;
case ENCAPSULATION_MODE | ISAKMP_ATTR_AF_TV:
ipcomp_inappropriate = FALSE;
switch (val)
{
case ENCAPSULATION_MODE_TUNNEL:
case ENCAPSULATION_MODE_TRANSPORT:
if (st->nat_traversal & NAT_T_DETECTED)
{
loglog(RC_LOG_SERIOUS
, "%s must only be used if NAT-Traversal is not detected"
, enum_name(&enc_mode_names, val));
/*
* Accept it anyway because SSH-Sentinel does not
* use UDP_TUNNEL or UDP_TRANSPORT for the diagnostic.
*
* remove when SSH-Sentinel is fixed
*/
#ifdef I_DONT_CARE_OF_SSH_SENTINEL
return FALSE;
#endif
}
attrs->encapsulation = val;
break;
case ENCAPSULATION_MODE_UDP_TRANSPORT_DRAFTS:
#ifndef I_KNOW_TRANSPORT_MODE_HAS_SECURITY_CONCERN_BUT_I_WANT_IT
loglog(RC_LOG_SERIOUS
, "NAT-Traversal: Transport mode disabled due to security concerns");
return FALSE;
#endif
case ENCAPSULATION_MODE_UDP_TUNNEL_DRAFTS:
if (st->nat_traversal & NAT_T_WITH_RFC_VALUES)
{
loglog(RC_LOG_SERIOUS
, "%s must only be used with old IETF drafts"
, enum_name(&enc_mode_names, val));
return FALSE;
}
else if (st->nat_traversal & NAT_T_DETECTED)
{
attrs->encapsulation = val
- ENCAPSULATION_MODE_UDP_TUNNEL_DRAFTS
+ ENCAPSULATION_MODE_TUNNEL;
}
else
{
loglog(RC_LOG_SERIOUS
, "%s must only be used if NAT-Traversal is detected"
, enum_name(&enc_mode_names, val));
return FALSE;
}
break;
case ENCAPSULATION_MODE_UDP_TRANSPORT_RFC:
#ifndef I_KNOW_TRANSPORT_MODE_HAS_SECURITY_CONCERN_BUT_I_WANT_IT
loglog(RC_LOG_SERIOUS
, "NAT-Traversal: Transport mode disabled due "
"to security concerns");
return FALSE;
#endif
case ENCAPSULATION_MODE_UDP_TUNNEL_RFC:
if ((st->nat_traversal & NAT_T_DETECTED)
&& (st->nat_traversal & NAT_T_WITH_RFC_VALUES))
{
attrs->encapsulation = val
- ENCAPSULATION_MODE_UDP_TUNNEL_RFC
+ ENCAPSULATION_MODE_TUNNEL;
}
else if (st->nat_traversal & NAT_T_DETECTED)
{
loglog(RC_LOG_SERIOUS
, "%s must only be used with NAT-T RFC"
, enum_name(&enc_mode_names, val));
return FALSE;
}
else
{
loglog(RC_LOG_SERIOUS
, "%s must only be used if NAT-Traversal is detected"
, enum_name(&enc_mode_names, val));
return FALSE;
}
break;
default:
loglog(RC_LOG_SERIOUS
, "unknown ENCAPSULATION_MODE %d in IPSec SA", val);
return FALSE;
}
break;
case AUTH_ALGORITHM | ISAKMP_ATTR_AF_TV:
attrs->auth = val;
break;
case KEY_LENGTH | ISAKMP_ATTR_AF_TV:
attrs->key_len = val;
break;
case KEY_ROUNDS | ISAKMP_ATTR_AF_TV:
attrs->key_rounds = val;
break;
#if 0 /* not yet implemented */
case COMPRESS_DICT_SIZE | ISAKMP_ATTR_AF_TV:
break;
case COMPRESS_PRIVATE_ALG | ISAKMP_ATTR_AF_TV:
break;
case SA_LIFE_DURATION | ISAKMP_ATTR_AF_TLV:
break;
case COMPRESS_PRIVATE_ALG | ISAKMP_ATTR_AF_TLV:
break;
#endif
default:
loglog(RC_LOG_SERIOUS, "unsupported IPsec attribute %s"
, enum_show(&ipsec_attr_names, a.isaat_af_type));
return FALSE;
}
if (ipcomp_inappropriate)
{
loglog(RC_LOG_SERIOUS, "IPsec attribute %s inappropriate for IPCOMP"
, enum_show(&ipsec_attr_names, a.isaat_af_type));
return FALSE;
}
}
/* Although an IPCOMP SA (IPCA) ought not to have a pfs_group,
* if it does, demand that it be consistent.
* See draft-shacham-ippcp-rfc2393bis-05.txt 4.1.
*/
if (!is_ipcomp || pfs_group != NULL)
{
if (st->st_pfs_group == &unset_group)
st->st_pfs_group = pfs_group;
if (st->st_pfs_group != pfs_group)
{
loglog(RC_LOG_SERIOUS, "GROUP_DESCRIPTION inconsistent with that of %s in IPsec SA"
, selection? "the Proposal" : "a previous Transform");
return FALSE;
}
}
if (LHAS(seen_attrs, SA_LIFE_DURATION))
{
loglog(RC_LOG_SERIOUS, "SA_LIFE_TYPE IPsec attribute not followed by SA_LIFE_DURATION attribute in message");
return FALSE;
}
if (!LHAS(seen_attrs, ENCAPSULATION_MODE))
{
if (is_ipcomp)
{
/* draft-shacham-ippcp-rfc2393bis-05.txt 4.1:
* "If the Encapsulation Mode is unspecified,
* the default value of Transport Mode is assumed."
* This contradicts/overrides the DOI (quuoted below).
*/
attrs->encapsulation = ENCAPSULATION_MODE_TRANSPORT;
}
else
{
/* ??? Technically, RFC 2407 (IPSEC DOI) 4.5 specifies that
* the default is "unspecified (host-dependent)".
* This makes little sense, so we demand that it be specified.
*/
loglog(RC_LOG_SERIOUS, "IPsec Transform must specify ENCAPSULATION_MODE");
return FALSE;
}
}
/* ??? should check for key_len and/or key_rounds if required */
return TRUE;
}
static void
echo_proposal(
struct isakmp_proposal r_proposal, /* proposal to emit */
struct isakmp_transform r_trans, /* winning transformation within it */
u_int8_t np, /* Next Payload for proposal */
pb_stream *r_sa_pbs, /* SA PBS into which to emit */
struct ipsec_proto_info *pi, /* info about this protocol instance */
struct_desc *trans_desc, /* descriptor for this transformation */
pb_stream *trans_pbs, /* PBS for incoming transform */
struct spd_route *sr, /* host details for the association */
bool tunnel_mode) /* true for inner most tunnel SA */
{
pb_stream r_proposal_pbs;
pb_stream r_trans_pbs;
/* Proposal */
r_proposal.isap_np = np;
r_proposal.isap_notrans = 1;
if (!out_struct(&r_proposal, &isakmp_proposal_desc, r_sa_pbs, &r_proposal_pbs))
impossible();
/* allocate and emit our CPI/SPI */
if (r_proposal.isap_protoid == PROTO_IPCOMP)
{
/* CPI is stored in network low order end of an
* ipsec_spi_t. So we start a couple of bytes in.
* Note: we may fail to generate a satisfactory CPI,
* but we'll ignore that.
*/
pi->our_spi = get_my_cpi(sr, tunnel_mode);
out_raw((u_char *) &pi->our_spi
+ IPSEC_DOI_SPI_SIZE - IPCOMP_CPI_SIZE
, IPCOMP_CPI_SIZE
, &r_proposal_pbs, "CPI");
}
else
{
pi->our_spi = get_ipsec_spi(pi->attrs.spi
, r_proposal.isap_protoid == PROTO_IPSEC_AH ?
IPPROTO_AH : IPPROTO_ESP
, sr
, tunnel_mode);
/* XXX should check for errors */
out_raw((u_char *) &pi->our_spi, IPSEC_DOI_SPI_SIZE
, &r_proposal_pbs, "SPI");
}
/* Transform */
r_trans.isat_np = ISAKMP_NEXT_NONE;
if (!out_struct(&r_trans, trans_desc, &r_proposal_pbs, &r_trans_pbs))
impossible();
/* Transform Attributes: pure echo */
trans_pbs->cur = trans_pbs->start + sizeof(struct isakmp_transform);
if (!out_raw(trans_pbs->cur, pbs_left(trans_pbs)
, &r_trans_pbs, "attributes"))
impossible();
close_output_pbs(&r_trans_pbs);
close_output_pbs(&r_proposal_pbs);
}
notification_t
parse_ipsec_sa_body(
pb_stream *sa_pbs, /* body of input SA Payload */
const struct isakmp_sa *sa, /* header of input SA Payload */
pb_stream *r_sa_pbs, /* if non-NULL, where to emit body of winning SA */
bool selection, /* if this SA is a selection, only one transform may appear */
struct state *st) /* current state object */
{
const struct connection *c = st->st_connection;
u_int32_t ipsecdoisit;
pb_stream next_proposal_pbs;
struct isakmp_proposal next_proposal;
ipsec_spi_t next_spi;
bool next_full = TRUE;
/* DOI */
if (sa->isasa_doi != ISAKMP_DOI_IPSEC)
{
loglog(RC_LOG_SERIOUS, "Unknown or unsupported DOI %s", enum_show(&doi_names, sa->isasa_doi));
/* XXX Could send notification back */
return DOI_NOT_SUPPORTED;
}
/* Situation */
if (!in_struct(&ipsecdoisit, &ipsec_sit_desc, sa_pbs, NULL))
return SITUATION_NOT_SUPPORTED;
if (ipsecdoisit != SIT_IDENTITY_ONLY)
{
loglog(RC_LOG_SERIOUS, "unsupported IPsec DOI situation (%s)"
, bitnamesof(sit_bit_names, ipsecdoisit));
/* XXX Could send notification back */
return SITUATION_NOT_SUPPORTED;
}
/* The rules for IPsec SAs are scattered.
* RFC 2408 "ISAKMP" section 4.2 gives some info.
* There may be multiple proposals. Those with identical proposal
* numbers must be considered as conjuncts. Those with different
* numbers are disjuncts.
* Each proposal may have several transforms, each considered
* an alternative.
* Each transform may have several attributes, all applying.
*
* To handle the way proposals are combined, we need to do a
* look-ahead.
*/
if (!in_struct(&next_proposal, &isakmp_proposal_desc, sa_pbs, &next_proposal_pbs))
return BAD_PROPOSAL_SYNTAX;
/* for each conjunction of proposals... */
while (next_full)
{
int propno = next_proposal.isap_proposal;
pb_stream ah_prop_pbs, esp_prop_pbs, ipcomp_prop_pbs;
struct isakmp_proposal ah_proposal = {0, 0, 0, 0, 0, 0, 0};
struct isakmp_proposal esp_proposal = {0, 0, 0, 0, 0, 0, 0};
struct isakmp_proposal ipcomp_proposal = {0, 0, 0, 0, 0, 0, 0};
ipsec_spi_t ah_spi = 0;
ipsec_spi_t esp_spi = 0;
ipsec_spi_t ipcomp_cpi = 0;
bool ah_seen = FALSE;
bool esp_seen = FALSE;
bool ipcomp_seen = FALSE;
bool tunnel_mode = FALSE;
int inner_proto = 0;
u_int16_t well_known_cpi = 0;
pb_stream ah_trans_pbs, esp_trans_pbs, ipcomp_trans_pbs;
struct isakmp_transform ah_trans, esp_trans, ipcomp_trans;
struct ipsec_trans_attrs ah_attrs, esp_attrs, ipcomp_attrs;
/* for each proposal in the conjunction */
do {
if (next_proposal.isap_protoid == PROTO_IPCOMP)
{
/* IPCOMP CPI */
if (next_proposal.isap_spisize == IPSEC_DOI_SPI_SIZE)
{
/* This code is to accommodate those peculiar
* implementations that send a CPI in the bottom of an
* SPI-sized field.
* See draft-shacham-ippcp-rfc2393bis-05.txt 4.1
*/
u_int8_t filler[IPSEC_DOI_SPI_SIZE - IPCOMP_CPI_SIZE];
if (!in_raw(filler, sizeof(filler)
, &next_proposal_pbs, "CPI filler")
|| !all_zero(filler, sizeof(filler)))
return INVALID_SPI;
}
else if (next_proposal.isap_spisize != IPCOMP_CPI_SIZE)
{
loglog(RC_LOG_SERIOUS, "IPsec Proposal with improper CPI size (%u)"
, next_proposal.isap_spisize);
return INVALID_SPI;
}
/* We store CPI in the low order of a network order
* ipsec_spi_t. So we start a couple of bytes in.
*/
zero(&next_spi);
if (!in_raw((u_char *)&next_spi
+ IPSEC_DOI_SPI_SIZE - IPCOMP_CPI_SIZE
, IPCOMP_CPI_SIZE, &next_proposal_pbs, "CPI"))
return INVALID_SPI;
/* If sanity ruled, CPIs would have to be such that
* the SAID (the triple (CPI, IPCOM, destination IP))
* would be unique, just like for SPIs. But there is a
* perversion where CPIs can be well-known and consequently
* the triple is not unique. We hide this fact from
* ourselves by fudging the top 16 bits to make
* the property true internally!
*/
switch (ntohl(next_spi))
{
case IPCOMP_DEFLATE:
well_known_cpi = ntohl(next_spi);
next_spi = uniquify_his_cpi(next_spi, st);
if (next_spi == 0)
{
loglog(RC_LOG_SERIOUS
, "IPsec Proposal contains well-known CPI that I cannot uniquify");
return INVALID_SPI;
}
break;
default:
if (ntohl(next_spi) < IPCOMP_FIRST_NEGOTIATED
|| ntohl(next_spi) > IPCOMP_LAST_NEGOTIATED)
{
loglog(RC_LOG_SERIOUS, "IPsec Proposal contains CPI from non-negotiated range (0x%lx)"
, (unsigned long) ntohl(next_spi));
return INVALID_SPI;
}
break;
}
}
else
{
/* AH or ESP SPI */
if (next_proposal.isap_spisize != IPSEC_DOI_SPI_SIZE)
{
loglog(RC_LOG_SERIOUS, "IPsec Proposal with improper SPI size (%u)"
, next_proposal.isap_spisize);
return INVALID_SPI;
}
if (!in_raw((u_char *)&next_spi, sizeof(next_spi), &next_proposal_pbs, "SPI"))
return INVALID_SPI;
/* SPI value 0 is invalid and values 1-255 are reserved to IANA.
* RFC 2402 (ESP) 2.4, RFC 2406 (AH) 2.1
* IPCOMP???
*/
if (ntohl(next_spi) < IPSEC_DOI_SPI_MIN)
{
loglog(RC_LOG_SERIOUS, "IPsec Proposal contains invalid SPI (0x%lx)"
, (unsigned long) ntohl(next_spi));
return INVALID_SPI;
}
}
if (next_proposal.isap_notrans == 0)
{
loglog(RC_LOG_SERIOUS, "IPsec Proposal contains no Transforms");
return BAD_PROPOSAL_SYNTAX;
}
switch (next_proposal.isap_protoid)
{
case PROTO_IPSEC_AH:
if (ah_seen)
{
loglog(RC_LOG_SERIOUS, "IPsec SA contains two simultaneous AH Proposals");
return BAD_PROPOSAL_SYNTAX;
}
ah_seen = TRUE;
ah_prop_pbs = next_proposal_pbs;
ah_proposal = next_proposal;
ah_spi = next_spi;
break;
case PROTO_IPSEC_ESP:
if (esp_seen)
{
loglog(RC_LOG_SERIOUS, "IPsec SA contains two simultaneous ESP Proposals");
return BAD_PROPOSAL_SYNTAX;
}
esp_seen = TRUE;
esp_prop_pbs = next_proposal_pbs;
esp_proposal = next_proposal;
esp_spi = next_spi;
break;
case PROTO_IPCOMP:
if (ipcomp_seen)
{
loglog(RC_LOG_SERIOUS, "IPsec SA contains two simultaneous IPCOMP Proposals");
return BAD_PROPOSAL_SYNTAX;
}
ipcomp_seen = TRUE;
ipcomp_prop_pbs = next_proposal_pbs;
ipcomp_proposal = next_proposal;
ipcomp_cpi = next_spi;
break;
default:
loglog(RC_LOG_SERIOUS, "unexpected Protocol ID (%s) in IPsec Proposal"
, enum_show(&protocol_names, next_proposal.isap_protoid));
return INVALID_PROTOCOL_ID;
}
/* refill next_proposal */
if (next_proposal.isap_np == ISAKMP_NEXT_NONE)
{
next_full = FALSE;
break;
}
else if (next_proposal.isap_np != ISAKMP_NEXT_P)
{
loglog(RC_LOG_SERIOUS, "unexpected in Proposal: %s"
, enum_show(&payload_names, next_proposal.isap_np));
return BAD_PROPOSAL_SYNTAX;
}
if (!in_struct(&next_proposal, &isakmp_proposal_desc, sa_pbs, &next_proposal_pbs))
return BAD_PROPOSAL_SYNTAX;
} while (next_proposal.isap_proposal == propno);
/* Now that we have all conjuncts, we should try
* the Cartesian product of eachs tranforms!
* At the moment, we take short-cuts on account of
* our rudimentary hard-wired policy.
* For now, we find an acceptable AH (if any)
* and then an acceptable ESP. The only interaction
* is that the ESP acceptance can know whether there
* was an acceptable AH and hence not require an AUTH.
*/
if (ah_seen)
{
int previous_transnum = -1;
int tn;
for (tn = 0; tn != ah_proposal.isap_notrans; tn++)
{
int ok_transid = 0;
bool ok_auth = FALSE;
if (!parse_ipsec_transform(&ah_trans
, &ah_attrs
, &ah_prop_pbs
, &ah_trans_pbs
, &isakmp_ah_transform_desc
, previous_transnum
, selection
, tn == ah_proposal.isap_notrans - 1
, FALSE
, st))
return BAD_PROPOSAL_SYNTAX;
previous_transnum = ah_trans.isat_transnum;
/* we must understand ah_attrs.transid
* COMBINED with ah_attrs.auth.
* See RFC 2407 "IPsec DOI" section 4.4.3
* The following combinations are legal,
* but we don't implement all of them:
* It seems as if each auth algorithm
* only applies to one ah transid.
* AH_MD5, AUTH_ALGORITHM_HMAC_MD5
* AH_MD5, AUTH_ALGORITHM_KPDK (unimplemented)
* AH_SHA, AUTH_ALGORITHM_HMAC_SHA1
* AH_DES, AUTH_ALGORITHM_DES_MAC (unimplemented)
*/
switch (ah_attrs.auth)
{
case AUTH_ALGORITHM_NONE:
loglog(RC_LOG_SERIOUS, "AUTH_ALGORITHM attribute missing in AH Transform");
return BAD_PROPOSAL_SYNTAX;
case AUTH_ALGORITHM_HMAC_MD5:
ok_auth = TRUE;
/* fall through */
case AUTH_ALGORITHM_KPDK:
ok_transid = AH_MD5;
break;
case AUTH_ALGORITHM_HMAC_SHA1:
ok_auth = TRUE;
ok_transid = AH_SHA;
break;
case AUTH_ALGORITHM_DES_MAC:
ok_transid = AH_DES;
break;
}
if (ah_attrs.transid != ok_transid)
{
loglog(RC_LOG_SERIOUS, "%s attribute inappropriate in %s Transform"
, enum_name(&auth_alg_names, ah_attrs.auth)
, enum_show(&ah_transformid_names, ah_attrs.transid));
return BAD_PROPOSAL_SYNTAX;
}
if (!ok_auth)
{
DBG(DBG_CONTROL | DBG_CRYPT
, DBG_log("%s attribute unsupported"
" in %s Transform from %s"
, enum_name(&auth_alg_names, ah_attrs.auth)
, enum_show(&ah_transformid_names, ah_attrs.transid)
, ip_str(&c->spd.that.host_addr)));
continue; /* try another */
}
break; /* we seem to be happy */
}
if (tn == ah_proposal.isap_notrans)
continue; /* we didn't find a nice one */
ah_attrs.spi = ah_spi;
inner_proto = IPPROTO_AH;
if (ah_attrs.encapsulation == ENCAPSULATION_MODE_TUNNEL)
tunnel_mode = TRUE;
}
if (esp_seen)
{
int previous_transnum = -1;
int tn;
for (tn = 0; tn != esp_proposal.isap_notrans; tn++)
{
if (!parse_ipsec_transform(&esp_trans
, &esp_attrs
, &esp_prop_pbs
, &esp_trans_pbs
, &isakmp_esp_transform_desc
, previous_transnum
, selection
, tn == esp_proposal.isap_notrans - 1
, FALSE
, st))
return BAD_PROPOSAL_SYNTAX;
previous_transnum = esp_trans.isat_transnum;
/* set default key length for AES encryption */
if (!esp_attrs.key_len && esp_attrs.transid == ESP_AES)
{
esp_attrs.key_len = 128; /* bits */
}
if (!kernel_alg_esp_enc_ok(esp_attrs.transid, esp_attrs.key_len
,c->alg_info_esp))
{
switch (esp_attrs.transid)
{
case ESP_3DES:
break;
#ifdef SUPPORT_ESP_NULL /* should be about as secure as AH-only */
case ESP_NULL:
if (esp_attrs.auth == AUTH_ALGORITHM_NONE)
{
loglog(RC_LOG_SERIOUS, "ESP_NULL requires auth algorithm");
return BAD_PROPOSAL_SYNTAX;
}
if (st->st_policy & POLICY_ENCRYPT)
{
DBG(DBG_CONTROL | DBG_CRYPT
, DBG_log("ESP_NULL Transform Proposal from %s"
" does not satisfy POLICY_ENCRYPT"
, ip_str(&c->spd.that.host_addr)));
continue; /* try another */
}
break;
#endif
default:
DBG(DBG_CONTROL | DBG_CRYPT
, DBG_log("unsupported ESP Transform %s from %s"
, enum_show(&esp_transformid_names, esp_attrs.transid)
, ip_str(&c->spd.that.host_addr)));
continue; /* try another */
}
}
if (!kernel_alg_esp_auth_ok(esp_attrs.auth, c->alg_info_esp))
{
switch (esp_attrs.auth)
{
case AUTH_ALGORITHM_NONE:
if (!ah_seen)
{
DBG(DBG_CONTROL | DBG_CRYPT
, DBG_log("ESP from %s must either have AUTH or be combined with AH"
, ip_str(&c->spd.that.host_addr)));
continue; /* try another */
}
break;
case AUTH_ALGORITHM_HMAC_MD5:
case AUTH_ALGORITHM_HMAC_SHA1:
break;
default:
DBG(DBG_CONTROL | DBG_CRYPT
, DBG_log("unsupported ESP auth alg %s from %s"
, enum_show(&auth_alg_names, esp_attrs.auth)
, ip_str(&c->spd.that.host_addr)));
continue; /* try another */
}
}
/* A last check for allowed transforms in alg_info_esp
* (ALG_INFO_F_STRICT flag)
*/
if (!kernel_alg_esp_ok_final(esp_attrs.transid, esp_attrs.key_len
,esp_attrs.auth, c->alg_info_esp))
{
continue;
}
if (ah_seen && ah_attrs.encapsulation != esp_attrs.encapsulation)
{
/* ??? This should be an error, but is it? */
DBG(DBG_CONTROL | DBG_CRYPT
, DBG_log("AH and ESP transforms disagree about encapsulation; TUNNEL presumed"));
}
break; /* we seem to be happy */
}
if (tn == esp_proposal.isap_notrans)
continue; /* we didn't find a nice one */
esp_attrs.spi = esp_spi;
inner_proto = IPPROTO_ESP;
if (esp_attrs.encapsulation == ENCAPSULATION_MODE_TUNNEL)
tunnel_mode = TRUE;
}
else if (st->st_policy & POLICY_ENCRYPT)
{
DBG(DBG_CONTROL | DBG_CRYPT
, DBG_log("policy for \"%s\" requires encryption but ESP not in Proposal from %s"
, c->name, ip_str(&c->spd.that.host_addr)));
continue; /* we needed encryption, but didn't find ESP */
}
else if ((st->st_policy & POLICY_AUTHENTICATE) && !ah_seen)
{
DBG(DBG_CONTROL | DBG_CRYPT
, DBG_log("policy for \"%s\" requires authentication"
" but none in Proposal from %s"
, c->name, ip_str(&c->spd.that.host_addr)));
continue; /* we need authentication, but we found neither ESP nor AH */
}
if (ipcomp_seen)
{
int previous_transnum = -1;
int tn;
#ifdef NEVER /* we think IPcomp is working now */
/**** FUDGE TO PREVENT UNREQUESTED IPCOMP:
**** NEEDED BECAUSE OUR IPCOMP IS EXPERIMENTAL (UNSTABLE).
****/
if (!(st->st_policy & POLICY_COMPRESS))
{
plog("compression proposed by %s, but policy for \"%s\" forbids it"
, ip_str(&c->spd.that.host_addr), c->name);
continue; /* unwanted compression proposal */
}
#endif
if (!can_do_IPcomp)
{
plog("compression proposed by %s, but KLIPS is not configured with IPCOMP"
, ip_str(&c->spd.that.host_addr));
continue;
}
if (well_known_cpi != 0 && !ah_seen && !esp_seen)
{
plog("illegal proposal: bare IPCOMP used with well-known CPI");
return BAD_PROPOSAL_SYNTAX;
}
for (tn = 0; tn != ipcomp_proposal.isap_notrans; tn++)
{
if (!parse_ipsec_transform(&ipcomp_trans
, &ipcomp_attrs
, &ipcomp_prop_pbs
, &ipcomp_trans_pbs
, &isakmp_ipcomp_transform_desc
, previous_transnum
, selection
, tn == ipcomp_proposal.isap_notrans - 1
, TRUE
, st))
return BAD_PROPOSAL_SYNTAX;
previous_transnum = ipcomp_trans.isat_transnum;
if (well_known_cpi != 0 && ipcomp_attrs.transid != well_known_cpi)
{
plog("illegal proposal: IPCOMP well-known CPI disagrees with transform");
return BAD_PROPOSAL_SYNTAX;
}
switch (ipcomp_attrs.transid)
{
case IPCOMP_DEFLATE: /* all we can handle! */
break;
default:
DBG(DBG_CONTROL | DBG_CRYPT
, DBG_log("unsupported IPCOMP Transform %s from %s"
, enum_show(&ipcomp_transformid_names, ipcomp_attrs.transid)
, ip_str(&c->spd.that.host_addr)));
continue; /* try another */
}
if (ah_seen && ah_attrs.encapsulation != ipcomp_attrs.encapsulation)
{
/* ??? This should be an error, but is it? */
DBG(DBG_CONTROL | DBG_CRYPT
, DBG_log("AH and IPCOMP transforms disagree about encapsulation; TUNNEL presumed"));
} else if (esp_seen && esp_attrs.encapsulation != ipcomp_attrs.encapsulation)
{
/* ??? This should be an error, but is it? */
DBG(DBG_CONTROL | DBG_CRYPT
, DBG_log("ESP and IPCOMP transforms disagree about encapsulation; TUNNEL presumed"));
}
break; /* we seem to be happy */
}
if (tn == ipcomp_proposal.isap_notrans)
continue; /* we didn't find a nice one */
ipcomp_attrs.spi = ipcomp_cpi;
inner_proto = IPPROTO_COMP;
if (ipcomp_attrs.encapsulation == ENCAPSULATION_MODE_TUNNEL)
tunnel_mode = TRUE;
}
/* Eureka: we liked what we saw -- accept it. */
if (r_sa_pbs != NULL)
{
/* emit what we've accepted */
/* Situation */
if (!out_struct(&ipsecdoisit, &ipsec_sit_desc, r_sa_pbs, NULL))
impossible();
/* AH proposal */
if (ah_seen)
echo_proposal(ah_proposal
, ah_trans
, esp_seen || ipcomp_seen? ISAKMP_NEXT_P : ISAKMP_NEXT_NONE
, r_sa_pbs
, &st->st_ah
, &isakmp_ah_transform_desc
, &ah_trans_pbs
, &st->st_connection->spd
, tunnel_mode && inner_proto == IPPROTO_AH);
/* ESP proposal */
if (esp_seen)
echo_proposal(esp_proposal
, esp_trans
, ipcomp_seen? ISAKMP_NEXT_P : ISAKMP_NEXT_NONE
, r_sa_pbs
, &st->st_esp
, &isakmp_esp_transform_desc
, &esp_trans_pbs
, &st->st_connection->spd
, tunnel_mode && inner_proto == IPPROTO_ESP);
/* IPCOMP proposal */
if (ipcomp_seen)
echo_proposal(ipcomp_proposal
, ipcomp_trans
, ISAKMP_NEXT_NONE
, r_sa_pbs
, &st->st_ipcomp
, &isakmp_ipcomp_transform_desc
, &ipcomp_trans_pbs
, &st->st_connection->spd
, tunnel_mode && inner_proto == IPPROTO_COMP);
close_output_pbs(r_sa_pbs);
}
/* save decoded version of winning SA in state */
st->st_ah.present = ah_seen;
if (ah_seen)
st->st_ah.attrs = ah_attrs;
st->st_esp.present = esp_seen;
if (esp_seen)
st->st_esp.attrs = esp_attrs;
st->st_ipcomp.present = ipcomp_seen;
if (ipcomp_seen)
st->st_ipcomp.attrs = ipcomp_attrs;
return NOTHING_WRONG;
}
loglog(RC_LOG_SERIOUS, "no acceptable Proposal in IPsec SA");
return NO_PROPOSAL_CHOSEN;
}
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