ipf/netinet/ip_ipsec_pxy.c

/*
 * Copyright (C) 2001-2003 by Darren Reed
 *
 * See the IPFILTER.LICENCE file for details on licencing.
 *
 * Simple ISAKMP transparent proxy for in-kernel use.  For use with the NAT
 * code.
 *
 * $Id: ip_ipsec_pxy.c,v 2.20.2.7 2005/07/15 21:56:50 darrenr Exp $
 *
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#define IPF_IPSEC_PROXY

typedef struct ifs_ipsecpxy {
    frentry_t       ipsecfr;
    ipftq_t         *ipsecnattqe;
    ipftq_t         *ipsecstatetqe;
    char            ipsec_buffer[1500];
    int         ipsec_proxy_init;
    int         ipsec_proxy_ttl;
} ifs_ipsecpxy_t;

int ippr_ipsec_init __P((void **, ipf_stack_t *));
void ippr_ipsec_fini __P((void **, ipf_stack_t *));
int ippr_ipsec_new __P((fr_info_t *, ap_session_t *, nat_t *, void *));
void ippr_ipsec_del __P((ap_session_t *, void *, ipf_stack_t *));
int ippr_ipsec_inout __P((fr_info_t *, ap_session_t *, nat_t *, void *));
int ippr_ipsec_match __P((fr_info_t *, ap_session_t *, nat_t *, void *));

/*
 * IPSec application proxy initialization.
 */
int ippr_ipsec_init(private, ifs)
void **private;
ipf_stack_t *ifs;
{
    ifs_ipsecpxy_t *ifsipsec;

    KMALLOC(ifsipsec, ifs_ipsecpxy_t *);
    if (ifsipsec == NULL)
        return -1;

    bzero((char *)&ifsipsec->ipsecfr, sizeof(ifsipsec->ipsecfr));
    ifsipsec->ipsecfr.fr_ref = 1;
    ifsipsec->ipsecfr.fr_flags = FR_OUTQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;
    MUTEX_INIT(&ifsipsec->ipsecfr.fr_lock, "IPsec proxy rule lock");
    ifsipsec->ipsec_proxy_init = 1;
    ifsipsec->ipsec_proxy_ttl = 60;

    ifsipsec->ipsecnattqe = fr_addtimeoutqueue(&ifs->ifs_nat_utqe, ifsipsec->ipsec_proxy_ttl, ifs);
    if (ifsipsec->ipsecnattqe == NULL) {
        MUTEX_DESTROY(&ifsipsec->ipsecfr.fr_lock);
        KFREE(ifsipsec);
        return -1;
    }
    ifsipsec->ipsecstatetqe = fr_addtimeoutqueue(&ifs->ifs_ips_utqe, ifsipsec->ipsec_proxy_ttl, ifs);
    if (ifsipsec->ipsecstatetqe == NULL) {
        if (fr_deletetimeoutqueue(ifsipsec->ipsecnattqe) == 0)
            fr_freetimeoutqueue(ifsipsec->ipsecnattqe, ifs);
        ifsipsec->ipsecnattqe = NULL;
        MUTEX_DESTROY(&ifsipsec->ipsecfr.fr_lock);
        KFREE(ifsipsec);
        return -1;
    }

    ifsipsec->ipsecnattqe->ifq_flags |= IFQF_PROXY;
    ifsipsec->ipsecstatetqe->ifq_flags |= IFQF_PROXY;

    ifsipsec->ipsecfr.fr_age[0] = ifsipsec->ipsec_proxy_ttl;
    ifsipsec->ipsecfr.fr_age[1] = ifsipsec->ipsec_proxy_ttl;

    *private = (void *)ifsipsec;

    return 0;
}


void ippr_ipsec_fini(private, ifs)
void **private;
ipf_stack_t *ifs;
{
    ifs_ipsecpxy_t *ifsipsec = *((ifs_ipsecpxy_t **)private);

    if (ifsipsec->ipsecnattqe != NULL) {
        if (fr_deletetimeoutqueue(ifsipsec->ipsecnattqe) == 0)
            fr_freetimeoutqueue(ifsipsec->ipsecnattqe, ifs);
    }
    ifsipsec->ipsecnattqe = NULL;
    if (ifsipsec->ipsecstatetqe != NULL) {
        if (fr_deletetimeoutqueue(ifsipsec->ipsecstatetqe) == 0)
            fr_freetimeoutqueue(ifsipsec->ipsecstatetqe, ifs);
    }
    ifsipsec->ipsecstatetqe = NULL;

    if (ifsipsec->ipsec_proxy_init == 1) {
        MUTEX_DESTROY(&ifsipsec->ipsecfr.fr_lock);
        ifsipsec->ipsec_proxy_init = 0;
    }

    KFREE(ifsipsec);
    *private = NULL;
}


/*
 * Setup for a new IPSEC proxy.
 */
int ippr_ipsec_new(fin, aps, nat, private)
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
void *private;
{
    ipsec_pxy_t *ipsec;
    fr_info_t fi;
    ipnat_t *ipn;
    char *ptr;
    int p, off, dlen, ttl;
    mb_t *m;
    ip_t *ip;
    ipf_stack_t *ifs = fin->fin_ifs;
    ifs_ipsecpxy_t *ifsipsec = (ifs_ipsecpxy_t *)private;

    off = fin->fin_plen - fin->fin_dlen + fin->fin_ipoff;
    bzero(ifsipsec->ipsec_buffer, sizeof(ifsipsec->ipsec_buffer));
    ip = fin->fin_ip;
    m = fin->fin_m;

    dlen = M_LEN(m) - off;
    if (dlen < 16)
        return -1;
    COPYDATA(m, off, MIN(sizeof(ifsipsec->ipsec_buffer), dlen),
         ifsipsec->ipsec_buffer);

    if (nat_outlookup(fin, 0, IPPROTO_ESP, nat->nat_inip,
              ip->ip_dst) != NULL)
        return -1;

    aps->aps_psiz = sizeof(*ipsec);
    KMALLOCS(aps->aps_data, ipsec_pxy_t *, sizeof(*ipsec));
    if (aps->aps_data == NULL)
        return -1;

    ipsec = aps->aps_data;
    bzero((char *)ipsec, sizeof(*ipsec));

    /*
     * Create NAT rule against which the tunnel/transport mapping is
     * created.  This is required because the current NAT rule does not
     * describe ESP but UDP instead.
     */
    ipn = &ipsec->ipsc_rule;
    ttl = IPF_TTLVAL(ifsipsec->ipsecnattqe->ifq_ttl);
    ipn->in_tqehead[0] = fr_addtimeoutqueue(&ifs->ifs_nat_utqe, ttl, ifs);
    ipn->in_tqehead[1] = fr_addtimeoutqueue(&ifs->ifs_nat_utqe, ttl, ifs);
    ipn->in_ifps[0] = fin->fin_ifp;
    ipn->in_apr = NULL;
    ipn->in_use = 1;
    ipn->in_hits = 1;
    ipn->in_nip = ntohl(nat->nat_outip.s_addr);
    ipn->in_ippip = 1;
    ipn->in_inip = nat->nat_inip.s_addr;
    ipn->in_inmsk = 0xffffffff;
    ipn->in_outip = fin->fin_saddr;
    ipn->in_outmsk = nat->nat_outip.s_addr;
    ipn->in_srcip = fin->fin_saddr;
    ipn->in_srcmsk = 0xffffffff;
    ipn->in_redir = NAT_MAP;
    bcopy(nat->nat_ptr->in_ifnames[0], ipn->in_ifnames[0],
          sizeof(ipn->in_ifnames[0]));
    ipn->in_p = IPPROTO_ESP;

    bcopy((char *)fin, (char *)&fi, sizeof(fi));
    fi.fin_fi.fi_p = IPPROTO_ESP;
    fi.fin_fr = &ifsipsec->ipsecfr;
    fi.fin_data[0] = 0;
    fi.fin_data[1] = 0;
    p = ip->ip_p;
    ip->ip_p = IPPROTO_ESP;
    fi.fin_flx &= ~(FI_TCPUDP|FI_STATE|FI_FRAG);
    fi.fin_flx |= FI_IGNORE;

    ptr = ifsipsec->ipsec_buffer;
    bcopy(ptr, (char *)ipsec->ipsc_icookie, sizeof(ipsec_cookie_t));
    ptr += sizeof(ipsec_cookie_t);
    bcopy(ptr, (char *)ipsec->ipsc_rcookie, sizeof(ipsec_cookie_t));
    /*
     * The responder cookie should only be non-zero if the initiator
     * cookie is non-zero.  Therefore, it is safe to assume(!) that the
     * cookies are both set after copying if the responder is non-zero.
     */
    if ((ipsec->ipsc_rcookie[0]|ipsec->ipsc_rcookie[1]) != 0)
        ipsec->ipsc_rckset = 1;

    ipsec->ipsc_nat = nat_new(&fi, ipn, &ipsec->ipsc_nat,
                  NAT_SLAVE|SI_WILDP, NAT_OUTBOUND);
    if (ipsec->ipsc_nat != NULL) {
        (void) nat_proto(&fi, ipsec->ipsc_nat, 0);
        nat_update(&fi, ipsec->ipsc_nat, ipn);

        fi.fin_data[0] = 0;
        fi.fin_data[1] = 0;
        ipsec->ipsc_state = fr_addstate(&fi, &ipsec->ipsc_state,
                        SI_WILDP);
    }
    ip->ip_p = p & 0xff;
    return 0;
}


/*
 * For outgoing IKE packets.  refresh timeouts for NAT & state entries, if
 * we can.  If they have disappeared, recreate them.
 */
int ippr_ipsec_inout(fin, aps, nat, private)
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
void *private;
{
    ipsec_pxy_t *ipsec;
    fr_info_t fi;
    ip_t *ip;
    int p;
    ipf_stack_t *ifs = fin->fin_ifs;
    ifs_ipsecpxy_t *ifsipsec = (ifs_ipsecpxy_t *)private;

    if ((fin->fin_out == 1) && (nat->nat_dir == NAT_INBOUND))
        return 0;

    if ((fin->fin_out == 0) && (nat->nat_dir == NAT_OUTBOUND))
        return 0;

    ipsec = aps->aps_data;

    if (ipsec != NULL) {
        ip = fin->fin_ip;
        p = ip->ip_p;

        if ((ipsec->ipsc_nat == NULL) || (ipsec->ipsc_state == NULL)) {
            bcopy((char *)fin, (char *)&fi, sizeof(fi));
            fi.fin_fi.fi_p = IPPROTO_ESP;
            fi.fin_fr = &ifsipsec->ipsecfr;
            fi.fin_data[0] = 0;
            fi.fin_data[1] = 0;
            ip->ip_p = IPPROTO_ESP;
            fi.fin_flx &= ~(FI_TCPUDP|FI_STATE|FI_FRAG);
            fi.fin_flx |= FI_IGNORE;
        }

        /*
         * Update NAT timeout/create NAT if missing.
         */
        if (ipsec->ipsc_nat != NULL)
            fr_queueback(&ipsec->ipsc_nat->nat_tqe, ifs);
        else {
            ipsec->ipsc_nat = nat_new(&fi, &ipsec->ipsc_rule,
                          &ipsec->ipsc_nat,
                          NAT_SLAVE|SI_WILDP,
                          nat->nat_dir);
            if (ipsec->ipsc_nat != NULL) {
                (void) nat_proto(&fi, ipsec->ipsc_nat, 0);
                nat_update(&fi, ipsec->ipsc_nat,
                       &ipsec->ipsc_rule);
            }
        }

        /*
         * Update state timeout/create state if missing.
         */
        READ_ENTER(&ifs->ifs_ipf_state);
        if (ipsec->ipsc_state != NULL) {
            fr_queueback(&ipsec->ipsc_state->is_sti, ifs);
            ipsec->ipsc_state->is_die = nat->nat_age;
            RWLOCK_EXIT(&ifs->ifs_ipf_state);
        } else {
            RWLOCK_EXIT(&ifs->ifs_ipf_state);
            fi.fin_data[0] = 0;
            fi.fin_data[1] = 0;
            ipsec->ipsc_state = fr_addstate(&fi,
                            &ipsec->ipsc_state,
                            SI_WILDP);
        }
        ip->ip_p = p;
    }
    return 0;
}


/*
 * This extends the NAT matching to be based on the cookies associated with
 * a session and found at the front of IKE packets.  The cookies are always
 * in the same order (not reversed depending on packet flow direction as with
 * UDP/TCP port numbers).
 */
/*ARGSUSED*/
int ippr_ipsec_match(fin, aps, nat, private)
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
void *private;
{
    ipsec_pxy_t *ipsec;
    u_32_t cookies[4];
    mb_t *m;
    int off;

    nat = nat;  /* LINT */

    if ((fin->fin_dlen < sizeof(cookies)) || (fin->fin_flx & FI_FRAG))
        return -1;

    off = fin->fin_plen - fin->fin_dlen + fin->fin_ipoff;
    ipsec = aps->aps_data;
    m = fin->fin_m;
    COPYDATA(m, off, sizeof(cookies), (char *)cookies);

    if ((cookies[0] != ipsec->ipsc_icookie[0]) ||
        (cookies[1] != ipsec->ipsc_icookie[1]))
        return -1;

    if (ipsec->ipsc_rckset == 0) {
        if ((cookies[2]|cookies[3]) == 0) {
            return 0;
        }
        ipsec->ipsc_rckset = 1;
        ipsec->ipsc_rcookie[0] = cookies[2];
        ipsec->ipsc_rcookie[1] = cookies[3];
        return 0;
    }

    if ((cookies[2] != ipsec->ipsc_rcookie[0]) ||
        (cookies[3] != ipsec->ipsc_rcookie[1]))
        return -1;
    return 0;
}


/*
 * clean up after ourselves.
 */
/*ARGSUSED*/
void ippr_ipsec_del(aps, private, ifs)
ap_session_t *aps;
void *private;
ipf_stack_t *ifs;
{
    ipsec_pxy_t *ipsec;

    ipsec = aps->aps_data;

    if (ipsec != NULL) {
        /*
         * Don't bother changing any of the NAT structure details,
         * *_del() is on a callback from aps_free(), from nat_delete()
         */

        READ_ENTER(&ifs->ifs_ipf_state);
        if (ipsec->ipsc_state != NULL) {
            ipsec->ipsc_state->is_die = ifs->ifs_fr_ticks + 1;
            ipsec->ipsc_state->is_me = NULL;
            fr_queuefront(&ipsec->ipsc_state->is_sti);
        }
        RWLOCK_EXIT(&ifs->ifs_ipf_state);

        ipsec->ipsc_state = NULL;
        ipsec->ipsc_nat = NULL;
    }
}