ttls.c

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/*
 * rlm_eap_ttls.c  contains the interfaces that are called from eap
 *
 * Version:     $Id: f37ba0e59ee4634d97d2c95375d138cb3cdba6bf $
 *
 *   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.
 *
 *   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.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 *
 *   Copyright 2003 Alan DeKok <aland@freeradius.org>
 *   Copyright 2006 The FreeRADIUS server project
 */

RCSID("$Id: f37ba0e59ee4634d97d2c95375d138cb3cdba6bf $")

#include "eap_ttls.h"
#include "eap_chbind.h"

/*
 *    0                   1                   2                   3
 *    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *   |                           AVP Code                            |
 *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *   |V M r r r r r r|                  AVP Length                   |
 *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *   |                        Vendor-ID (opt)                        |
 *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *   |    Data ...
 *   +-+-+-+-+-+-+-+-+
 */

/*
 *      Verify that the diameter packet is valid.
 */
static int diameter_verify(REQUEST *request, uint8_t const *data, unsigned int data_len)
{
        uint32_t attr;
        uint32_t length;
        unsigned int hdr_len;
        unsigned int remaining = data_len;

        while (remaining > 0) {
                hdr_len = 12;

                if (remaining < hdr_len) {
                  RDEBUG2("Diameter attribute is too small (%u) to contain a Diameter header", remaining);
                        return 0;
                }

                memcpy(&attr, data, sizeof(attr));
                attr = ntohl(attr);
                memcpy(&length, data + 4, sizeof(length));
                length = ntohl(length);

                if ((data[4] & 0x80) != 0) {
                        if (remaining < 16) {
                                RDEBUG2("Diameter attribute is too small to contain a Diameter header with Vendor-Id");
                                return 0;
                        }

                        hdr_len = 16;
                }

                /*
                 *      Get the length.  If it's too big, die.
                 */
                length &= 0x00ffffff;

                /*
                 *      Too short or too long is bad.
                 */
                if (length <= (hdr_len - 4)) {
                        RDEBUG2("Tunneled attribute %u is too short (%u < %u) to contain anything useful.", attr,
                                length, hdr_len);
                        return 0;
                }

                if (length > remaining) {
                        RDEBUG2("Tunneled attribute %u is longer than room remaining in the packet (%u > %u).", attr,
                                length, remaining);
                        return 0;
                }

                /*
                 *      Check for broken implementations, which don't
                 *      pad the AVP to a 4-octet boundary.
                 */
                if (remaining == length) break;

                /*
                 *      The length does NOT include the padding, so
                 *      we've got to account for it here by rounding up
                 *      to the nearest 4-byte boundary.
                 */
                length += 0x03;
                length &= ~0x03;

                /*
                 *      If the rest of the diameter packet is larger than
                 *      this attribute, continue.
                 *
                 *      Otherwise, if the attribute over-flows the end
                 *      of the packet, die.
                 */
                if (remaining < length) {
                        REDEBUG2("Diameter attribute overflows packet!");
                        return 0;
                }

                /*
                 *      remaining > length, continue.
                 */
                remaining -= length;
                data += length;
        }

        /*
         *      We got this far.  It looks OK.
         */
        return 1;
}


/*
 *      Convert diameter attributes to our VALUE_PAIR's
 */
static VALUE_PAIR *diameter2vp(REQUEST *request, REQUEST *fake, SSL *ssl,
                               uint8_t const *data, size_t data_len)
{
        uint32_t        attr;
        uint32_t        vendor;
        uint32_t        length;
        size_t          offset;
        size_t          size;
        size_t          data_left = data_len;
        VALUE_PAIR      *first = NULL;
        VALUE_PAIR      *vp = NULL;
        RADIUS_PACKET   *packet = fake->packet; /* FIXME: api issues */
        vp_cursor_t     out;

        fr_cursor_init(&out, &first);

        while (data_left > 0) {
                rad_assert(data_left <= data_len);
                memcpy(&attr, data, sizeof(attr));
                data += 4;
                attr = ntohl(attr);
                vendor = 0;

                memcpy(&length, data, sizeof(length));
                data += 4;
                length = ntohl(length);

                /*
                 *      A "vendor" flag, with a vendor ID of zero,
                 *      is equivalent to no vendor.  This is stupid.
                 */
                offset = 8;
                if ((length & ((uint32_t)1 << 31)) != 0) {
                        memcpy(&vendor, data, sizeof(vendor));
                        vendor = ntohl(vendor);

                        data += 4; /* skip the vendor field, it's zero */
                        offset += 4; /* offset to value field */

                        if (attr > 65535) goto next_attr;
                }

                /*
                 *      FIXME: Handle the M bit.  For now, we assume that
                 *      some other module takes care of any attribute
                 *      with the M bit set.
                 */

                /*
                 *      Get the length.
                 */
                length &= 0x00ffffff;

                /*
                 *      Get the size of the value portion of the
                 *      attribute.
                 */
                size = length - offset;

                /*
                 *      Vendor attributes can be larger than 255.
                 *      Normal attributes cannot be.
                 */
                if ((attr > 255) && (vendor == 0)) {
                        RWDEBUG2("Skipping Diameter attribute %u", attr);
                        goto next_attr;
                }

                /*
                 *      EAP-Message AVPs can be larger than 253 octets.
                 *
                 *      For now, we rely on the main decoder in
                 *      src/lib/radius to decode data into VPs.  This
                 *      means putting the data into a RADIUS attribute
                 *      format.  It also means that we can't handle
                 *      "extended" attributes in the Diameter space.  Oh well...
                 */
                if ((size > 253) && !((vendor == 0) && (attr == PW_EAP_MESSAGE))) {
                        RWDEBUG2("diameter2vp skipping long attribute %u", attr);
                        goto next_attr;
                }

                /*
                 *      RADIUS VSAs are handled as Diameter attributes
                 *      with Vendor-Id == 0, and the VSA data packed
                 *      into the "String" field as per normal.
                 *
                 *      EXCEPT for the MS-CHAP attributes.
                 */
                if ((vendor == 0) && (attr == PW_VENDOR_SPECIFIC)) {
                        ssize_t         decoded;
                        uint8_t         buffer[256];
                        vp_cursor_t     cursor;

                        buffer[0] = PW_VENDOR_SPECIFIC;
                        buffer[1] = size + 2;
                        memcpy(buffer + 2, data, size);

                        fr_cursor_init(&cursor, &vp);
                        decoded = fr_radius_decode_pair(packet, &cursor, fr_dict_root(fr_dict_internal),
                                                        buffer, size + 2, NULL);
                        if (decoded < 0) {
                                REDEBUG2("diameter2vp failed decoding attr: %s",
                                        fr_strerror());
                                goto do_octets;
                        }

                        if ((size_t) decoded != size + 2) {
                                REDEBUG2("diameter2vp failed to entirely decode VSA");
                                fr_pair_list_free(&vp);
                                goto do_octets;
                        }

                        fr_cursor_merge(&out, vp);

                        goto next_attr;
                }

                /*
                 *      Create it.  If this fails, it's because we're OOM.
                 */
        do_octets:
                vp = fr_pair_afrom_num(packet, vendor, attr);
                if (!vp) {
                        RDEBUG2("Failure in creating VP");
                        fr_pair_list_free(&first);
                        return NULL;
                }

                /*
                 *      If it's a type from our dictionary, then
                 *      we need to put the data in a relevant place.
                 *
                 *      @todo: Export the lib/radius.c decoder, and use it here!
                 */
                switch (vp->da->type) {
                case PW_TYPE_INTEGER:
                case PW_TYPE_DATE:
                        if (size != vp->vp_length) {
                                fr_dict_attr_t const *da;

                                /*
                                 *      Bad format.  Create a "raw"
                                 *      attribute.
                                 */
                raw:
                                if (vp) fr_pair_list_free(&vp);
                                da = fr_dict_unknown_afrom_fields(packet, fr_dict_root(fr_dict_internal), vendor, attr);
                                if (!da) return NULL;
                                vp = fr_pair_afrom_da(packet, da);
                                if (!vp) return NULL;
                                fr_pair_value_memcpy(vp, data, size);
                                break;
                        }
                        memcpy(&vp->vp_integer, data, vp->vp_length);

                        /*
                         *      Stored in host byte order: change it.
                         */
                        vp->vp_integer = ntohl(vp->vp_integer);
                        break;

                case PW_TYPE_INTEGER64:
                        if (size != vp->vp_length) goto raw;
                        memcpy(&vp->vp_integer64, data, vp->vp_length);

                        /*
                         *      Stored in host byte order: change it.
                         */
                        vp->vp_integer64 = ntohll(vp->vp_integer64);
                        break;

                case PW_TYPE_IPV4_ADDR:
                        if (size != vp->vp_length) {
                                RDEBUG2("Invalid length attribute %d",
                                       attr);
                                fr_pair_list_free(&first);
                                fr_pair_list_free(&vp);
                                return NULL;
                        }
                        memcpy(&vp->vp_ipaddr, data, vp->vp_length);

                        /*
                         *      Stored in network byte order: don't change it.
                         */
                        break;

                case PW_TYPE_BYTE:
                        if (size != vp->vp_length) goto raw;
                        vp->vp_byte = data[0];
                        break;

                case PW_TYPE_SHORT:
                        if (size != vp->vp_length) goto raw;
                        vp->vp_short = (data[0] * 256) + data[1];
                        break;

                case PW_TYPE_SIGNED:
                        if (size != vp->vp_length) goto raw;
                        memcpy(&vp->vp_signed, data, vp->vp_length);
                        vp->vp_signed = ntohl(vp->vp_signed);
                        break;

                case PW_TYPE_IPV6_ADDR:
                        if (size != vp->vp_length) goto raw;
                        memcpy(&vp->vp_ipv6addr, data, vp->vp_length);
                        break;

                case PW_TYPE_IPV6_PREFIX:
                        if (size != vp->vp_length) goto raw;
                        memcpy(vp->vp_ipv6prefix, data, vp->vp_length);
                        break;

                case PW_TYPE_STRING:
                        fr_pair_value_bstrncpy(vp, data, size);
                        vp->vp_length = strlen(vp->vp_strvalue); /* embedded zeros are NOT allowed */
                        break;

                        /*
                         *      Copy it over verbatim.
                         */
                case PW_TYPE_OCTETS:
                default:
                        fr_pair_value_memcpy(vp, data, size);
                        break;
                }

                /*
                 *      Ensure that the client is using the
                 *      correct challenge.  This weirdness is
                 *      to protect against against replay
                 *      attacks, where anyone observing the
                 *      CHAP exchange could pose as that user,
                 *      by simply choosing to use the same
                 *      challenge.
                 *
                 *      By using a challenge based on
                 *      information from the current session,
                 *      we can guarantee that the client is
                 *      not *choosing* a challenge.
                 *
                 *      We're a little forgiving in that we
                 *      have loose checks on the length, and
                 *      we do NOT check the Id (first octet of
                 *      the response to the challenge)
                 *
                 *      But if the client gets the challenge correct,
                 *      we're not too worried about the Id.
                 */
                if (((vp->da->vendor == 0) && (vp->da->attr == PW_CHAP_CHALLENGE)) ||
                    ((vp->da->vendor == VENDORPEC_MICROSOFT) && (vp->da->attr == PW_MSCHAP_CHALLENGE))) {
                        uint8_t challenge[16];

                        if ((vp->vp_length < 8) ||
                            (vp->vp_length > 16)) {
                                RDEBUG("Tunneled challenge has invalid length");
                                fr_pair_list_free(&first);
                                fr_pair_list_free(&vp);
                                return NULL;
                        }

                        eap_ttls_gen_challenge(ssl, challenge,
                                              sizeof(challenge));

                        if (memcmp(challenge, vp->vp_octets,
                                   vp->vp_length) != 0) {
                                RDEBUG("Tunneled challenge is incorrect");
                                fr_pair_list_free(&first);
                                fr_pair_list_free(&vp);
                                return NULL;
                        }
                }

                /*
                 *      Update the list.
                 */
                fr_cursor_insert(&out, vp);

        next_attr:
                /*
                 *      Catch non-aligned attributes.
                 */
                if (data_left == length) break;

                /*
                 *      The length does NOT include the padding, so
                 *      we've got to account for it here by rounding up
                 *      to the nearest 4-byte boundary.
                 */
                length += 0x03;
                length &= ~0x03;

                rad_assert(data_left >= length);
                data_left -= length;
                data += length - offset; /* already updated */
        }

        /*
         *      We got this far.  It looks OK.
         */
        return first;
}

/*
 *      Convert VALUE_PAIR's to diameter attributes, and write them
 *      to an SSL session.
 *
 *      The ONLY VALUE_PAIR's which may be passed to this function
 *      are ones which can go inside of a RADIUS (i.e. diameter)
 *      packet.  So no server-configuration attributes, or the like.
 */
static int vp2diameter(REQUEST *request, tls_session_t *tls_session, VALUE_PAIR *first)
{
        /*
         *      RADIUS packets are no more than 4k in size, so if
         *      we've got more than 4k of data to write, it's very
         *      bad.
         */
        uint8_t         buffer[4096];
        uint8_t         *p;
        uint32_t        attr;
        uint32_t        length;
        uint32_t        vendor;
        size_t          total;
        uint64_t        attr64;
        VALUE_PAIR      *vp;
        vp_cursor_t     cursor;

        p = buffer;
        total = 0;

        for (vp = fr_cursor_init(&cursor, &first); vp; vp = fr_cursor_next(&cursor)) {
                /*
                 *      Too much data: die.
                 */
                if ((total + vp->vp_length + 12) >= sizeof(buffer)) {
                        RDEBUG2("output buffer is full!");
                        return 0;
                }

                /*
                 *      Hmm... we don't group multiple EAP-Messages
                 *      together.  Maybe we should...
                 */

                length = vp->vp_length;
                vendor = vp->da->vendor;
                if (vendor != 0) {
                        attr = vp->da->attr & 0xffff;
                        length |= ((uint32_t)1 << 31);
                } else {
                        attr = vp->da->attr;
                }

                /*
                 *      Hmm... set the M bit for all attributes?
                 */
                length |= (1 << 30);

                attr = ntohl(attr);

                memcpy(p, &attr, sizeof(attr));
                p += 4;
                total += 4;

                length += 8;    /* includes 8 bytes of attr & length */

                if (vendor != 0) {
                        length += 4; /* include 4 bytes of vendor */

                        length = ntohl(length);
                        memcpy(p, &length, sizeof(length));
                        p += 4;
                        total += 4;

                        vendor = ntohl(vendor);
                        memcpy(p, &vendor, sizeof(vendor));
                        p += 4;
                        total += 4;
                } else {
                        length = ntohl(length);
                        memcpy(p, &length, sizeof(length));
                        p += 4;
                        total += 4;
                }

                switch (vp->da->type) {
                case PW_TYPE_INTEGER:
                case PW_TYPE_DATE:
                        attr = htonl(vp->vp_integer); /* stored in host order */
                        memcpy(p, &attr, sizeof(attr));
                        length = 4;
                        break;

                case PW_TYPE_INTEGER64:
                        attr64 = htonll(vp->vp_integer64); /* stored in host order */
                        memcpy(p, &attr64, sizeof(attr64));
                        length = 8;
                        break;

                case PW_TYPE_IPV4_ADDR:
                        memcpy(p, &vp->vp_ipaddr, 4); /* network order */
                        length = 4;
                        break;

                case PW_TYPE_STRING:
                case PW_TYPE_OCTETS:
                default:
                        memcpy(p, vp->vp_strvalue, vp->vp_length);
                        length = vp->vp_length;
                        break;
                }

                /*
                 *      Skip to the end of the data.
                 */
                p += length;
                total += length;

                /*
                 *      Align the data to a multiple of 4 bytes.
                 */
                if ((total & 0x03) != 0) {
                        size_t i;

                        length = 4 - (total & 0x03);
                        for (i = 0; i < length; i++) {
                                *p = '\0';
                                p++;
                                total++;
                        }
                }
        } /* loop over the VP's to write. */

        /*
         *      Write the data in the buffer to the SSL session.
         */
        if (total > 0) {
#ifndef NDEBUG
                size_t i;

                if ((rad_debug_lvl > 2) && fr_log_fp) {
                        for (i = 0; i < total; i++) {
                                if ((i & 0x0f) == 0) fprintf(fr_log_fp, "  TTLS tunnel data out %04x: ", (int) i);

                                fprintf(fr_log_fp, "%02x ", buffer[i]);

                                if ((i & 0x0f) == 0x0f) fprintf(fr_log_fp, "\n");
                        }
                        if ((total & 0x0f) != 0) fprintf(fr_log_fp, "\n");
                }
#endif

                (tls_session->record_from_buff)(&tls_session->clean_in, buffer, total);

                /*
                 *      FIXME: Check the return code.
                 */
                tls_handshake_send(request, tls_session);
        }

        /*
         *      Everything's OK.
         */
        return 1;
}

/*
 *      Use a reply packet to determine what to do.
 */
static rlm_rcode_t CC_HINT(nonnull) process_reply(eap_session_t *eap_session, tls_session_t *tls_session,
                                                  REQUEST *request, RADIUS_PACKET *reply)
{
        rlm_rcode_t rcode = RLM_MODULE_REJECT;
        VALUE_PAIR *vp;
        ttls_tunnel_t *t = tls_session->opaque;

        rad_assert(eap_session->request == request);

        /*
         *      If the response packet was Access-Accept, then
         *      we're OK.  If not, die horribly.
         *
         *      FIXME: Take MS-CHAP2-Success attribute, and
         *      tunnel it back to the client, to authenticate
         *      ourselves to the client.
         *
         *      FIXME: If we have an Access-Challenge, then
         *      the Reply-Message is tunneled back to the client.
         *
         *      FIXME: If we have an EAP-Message, then that message
         *      must be tunneled back to the client.
         *
         *      FIXME: If we have an Access-Challenge with a State
         *      attribute, then do we tunnel that to the client, or
         *      keep track of it ourselves?
         *
         *      FIXME: EAP-Messages can only start with 'identity',
         *      NOT 'eap start', so we should check for that....
         */
        switch (reply->code) {
        case PW_CODE_ACCESS_ACCEPT:
                RDEBUG("Got tunneled Access-Accept");

                rcode = RLM_MODULE_OK;

                /*
                 *      Always delete MPPE keys & encryption policy
                 *      from the tunneled reply.  These never get sent
                 *      back to the user.
                 */
                fr_pair_delete_by_num(&reply->vps, VENDORPEC_MICROSOFT, 7, TAG_ANY);
                fr_pair_delete_by_num(&reply->vps, VENDORPEC_MICROSOFT, 8, TAG_ANY);
                fr_pair_delete_by_num(&reply->vps, VENDORPEC_MICROSOFT, 16, TAG_ANY);
                fr_pair_delete_by_num(&reply->vps, VENDORPEC_MICROSOFT, 17, TAG_ANY);

                /*
                 *      MS-CHAP2-Success means that we do NOT return
                 *      an Access-Accept, but instead tunnel that
                 *      attribute to the client, and keep going with
                 *      the TTLS session.  Once the client accepts
                 *      our identity, it will respond with an empty
                 *      packet, and we will send EAP-Success.
                 */
                vp = NULL;
                fr_pair_list_mcopy_by_num(tls_session, &vp, &reply->vps, VENDORPEC_MICROSOFT, PW_MSCHAP2_SUCCESS,
                                          TAG_ANY);
                if (vp) {
                        RDEBUG("Got MS-CHAP2-Success, tunneling it to the client in a challenge");
                        rcode = RLM_MODULE_HANDLED;
                        t->authenticated = true;

                        /*
                         *      Use the tunneled reply, but not now.
                         */
                        if (t->use_tunneled_reply) {
                                rad_assert(!t->accept_vps);
                                fr_pair_list_mcopy_by_num(t, &t->accept_vps, &reply->vps, 0, 0, TAG_ANY);
                                rad_assert(!reply->vps);
                        }

                } else { /* no MS-CHAP2-Success */
                        /*
                         *      Can only have EAP-Message if there's
                         *      no MS-CHAP2-Success.
                         *
                         *      We also do NOT tunnel the EAP-Success
                         *      attribute back to the client, as the client
                         *      can figure it out, from the non-tunneled
                         *      EAP-Success packet.
                         */
                        fr_pair_list_mcopy_by_num(tls_session, &vp, &reply->vps, 0, PW_EAP_MESSAGE, TAG_ANY);
                        fr_pair_list_free(&vp);
                }

                /* move channel binding responses; we need to send them */
                fr_pair_list_mcopy_by_num(tls_session, &vp, &reply->vps, VENDORPEC_UKERNA, PW_UKERNA_CHBIND, TAG_ANY);
                if (fr_pair_find_by_num(vp, VENDORPEC_UKERNA, PW_UKERNA_CHBIND, TAG_ANY) != NULL) {
                        t->authenticated = true;
                        /*
                         *      Use the tunneled reply, but not now.
                         */
                        if (t->use_tunneled_reply) {
                                rad_assert(!t->accept_vps);
                                fr_pair_list_mcopy_by_num(t, &t->accept_vps, &reply->vps, 0, 0, TAG_ANY);
                                rad_assert(!reply->vps);
                        }
                        rcode = RLM_MODULE_HANDLED;
                }

                /*
                 *      Handle the ACK, by tunneling any necessary reply
                 *      VP's back to the client.
                 */
                if (vp) {
                        RDEBUG("Sending tunneled reply attributes");
                        rdebug_pair_list(L_DBG_LVL_1, request, vp, NULL);

                        vp2diameter(request, tls_session, vp);
                        fr_pair_list_free(&vp);
                }

                /*
                 *      If we've been told to use the attributes from
                 *      the reply, then do so.
                 *
                 *      WARNING: This may leak information about the
                 *      tunneled user!
                 */
                if (t->use_tunneled_reply) {
                        fr_pair_delete_by_num(&reply->vps, 0, PW_PROXY_STATE, TAG_ANY);
                        fr_pair_list_mcopy_by_num(request->reply, &request->reply->vps, &reply->vps, 0, 0, TAG_ANY);
                }
                break;


        case PW_CODE_ACCESS_REJECT:
                RDEBUG("Got tunneled Access-Reject");
                rcode = RLM_MODULE_REJECT;
                break;

                /*
                 *      Handle Access-Challenge, but only if we
                 *      send tunneled reply data.  This is because
                 *      an Access-Challenge means that we MUST tunnel
                 *      a Reply-Message to the client.
                 */
        case PW_CODE_ACCESS_CHALLENGE:
                RDEBUG("Got tunneled Access-Challenge");

                /*
                 *      Keep the State attribute, if necessary.
                 *
                 *      Get rid of the old State, too.
                 */
                fr_pair_list_free(&t->state);
                fr_pair_list_mcopy_by_num(t, &t->state, &reply->vps, 0, PW_STATE, TAG_ANY);

                /*
                 *      We should really be a bit smarter about this,
                 *      and move over only those attributes which
                 *      are relevant to the authentication request,
                 *      but that's a lot more work, and this "dumb"
                 *      method works in 99.9% of the situations.
                 */
                vp = NULL;
                fr_pair_list_mcopy_by_num(t, &vp, &reply->vps, 0, PW_EAP_MESSAGE, TAG_ANY);

                /*
                 *      There MUST be a Reply-Message in the challenge,
                 *      which we tunnel back to the client.
                 *
                 *      If there isn't one in the reply VP's, then
                 *      we MUST create one, with an empty string as
                 *      it's value.
                 */
                fr_pair_list_mcopy_by_num(t, &vp, &reply->vps, 0, PW_REPLY_MESSAGE, TAG_ANY);

                /* also move chbind messages, if any */
                fr_pair_list_mcopy_by_num(t, &vp, &reply->vps, VENDORPEC_UKERNA, PW_UKERNA_CHBIND, TAG_ANY);

                /*
                 *      Handle the ACK, by tunneling any necessary reply
                 *      VP's back to the client.
                 */
                if (vp) {
                        vp2diameter(request, tls_session, vp);
                        fr_pair_list_free(&vp);
                }
                rcode = RLM_MODULE_HANDLED;
                break;

        default:
                RDEBUG("Unknown RADIUS packet type %d: rejecting tunneled user", reply->code);
                rcode = RLM_MODULE_INVALID;
                break;
        }

        return rcode;
}


#ifdef WITH_PROXY
/*
 *      Do post-proxy processing,
 */
static int CC_HINT(nonnull) eap_ttls_postproxy(eap_session_t *eap_session, void *data)
{
        int rcode;
        tls_session_t *tls_session = (tls_session_t *) data;
        REQUEST *fake, *request = eap_session->request;

        RDEBUG("Passing reply from proxy back into the tunnel");

        /*
         *      If there was a fake request associated with the proxied
         *      request, do more processing of it.
         */
        fake = (REQUEST *) request_data_get(eap_session->request,
                                            eap_session->request->proxy,
                                            REQUEST_DATA_EAP_MSCHAP_TUNNEL_CALLBACK);

        /*
         *      Do the callback, if it exists, and if it was a success.
         */
        if (fake && (eap_session->request->proxy_reply->code == PW_CODE_ACCESS_ACCEPT)) {
                /*
                 *      Terrible hacks.
                 */
                rad_assert(!fake->packet);
                fake->packet = talloc_steal(fake, request->proxy);
                fake->packet->src_ipaddr = request->packet->src_ipaddr;
                request->proxy = NULL;

                rad_assert(!fake->reply);
                fake->reply = talloc_steal(fake, request->proxy_reply);
                request->proxy_reply = NULL;

                if ((rad_debug_lvl > 0) && fr_log_fp) {
                        fprintf(fr_log_fp, "server %s {\n",
                                (!fake->server) ? "" : fake->server);
                }

                /*
                 *      Perform a post-auth stage for the tunneled
                 *      session.
                 */
                fake->options &= ~RAD_REQUEST_OPTION_PROXY_EAP;
                rcode = rad_postauth(fake);
                RDEBUG2("post-auth returns %d", rcode);

                if ((rad_debug_lvl > 0) && fr_log_fp) {
                        fprintf(fr_log_fp, "} # server %s\n",
                                (!fake->server) ? "" : fake->server);

                        RDEBUG("Final reply from tunneled session code %d", fake->reply->code);
                        rdebug_pair_list(L_DBG_LVL_1, request, fake->reply->vps, NULL);
                }

                /*
                 *      Terrible hacks.
                 */
                request->proxy = talloc_steal(request, fake->packet);
                fake->packet = NULL;
                request->proxy_reply = talloc_steal(request, fake->reply);
                fake->reply = NULL;

                /*
                 *      And we're done with this request.
                 */

                switch (rcode) {
                case RLM_MODULE_FAIL:
                        talloc_free(fake);
                        eap_tls_fail(eap_session);
                        return 0;

                default:  /* Don't Do Anything */
                        RDEBUG2("Got reply %d",
                               request->proxy_reply->code);
                        break;
                }
        }
        talloc_free(fake);      /* robust if !fake */

        /*
         *      Process the reply from the home server.
         */
        rcode = process_reply(eap_session, tls_session, eap_session->request, eap_session->request->proxy_reply);

        /*
         *      The proxy code uses the reply from the home server as
         *      the basis for the reply to the NAS.  We don't want that,
         *      so we toss it, after we've had our way with it.
         */
        fr_pair_list_free(&eap_session->request->proxy_reply->vps);

        switch (rcode) {
        case RLM_MODULE_REJECT:
                RDEBUG("Reply was rejected");
                break;

        case RLM_MODULE_HANDLED:
                RDEBUG("Reply was handled");
                eap_tls_request(eap_session);
                request->proxy_reply->code = PW_CODE_ACCESS_CHALLENGE;
                return 1;

        case RLM_MODULE_OK:
                RDEBUG("Reply was OK");

                /*
                 *      Success: Automatically return MPPE keys.
                 */
                if (eap_tls_success(eap_session) < 0) return 0;
                return 1;

        default:
                RDEBUG("Reply was unknown");
                break;
        }

        eap_tls_fail(eap_session);
        return 0;
}

#endif  /* WITH_PROXY */

/*
 *      Process the "diameter" contents of the tunneled data.
 */
PW_CODE eap_ttls_process(eap_session_t *eap_session, tls_session_t *tls_session)
{
        PW_CODE code = PW_CODE_ACCESS_REJECT;
        rlm_rcode_t rcode;
        REQUEST *fake;
        VALUE_PAIR *vp;
        ttls_tunnel_t *t;
        uint8_t const *data;
        size_t data_len;
        REQUEST *request = eap_session->request;
        chbind_packet_t *chbind;

        /*
         *      Just look at the buffer directly, without doing
         *      record_to_buff.
         */
        data_len = tls_session->clean_out.used;
        tls_session->clean_out.used = 0;
        data = tls_session->clean_out.data;

        t = (ttls_tunnel_t *) tls_session->opaque;

        /*
         *      If there's no data, maybe this is an ACK to an
         *      MS-CHAP2-Success.
         */
        if (data_len == 0) {
                if (t->authenticated) {
                        RDEBUG("Got ACK, and the user was already authenticated");
                        return PW_CODE_ACCESS_ACCEPT;
                } /* else no session, no data, die. */

                /*
                 *      FIXME: Call SSL_get_error() to see what went
                 *      wrong.
                 */
                RDEBUG2("SSL_read Error");
                return PW_CODE_ACCESS_REJECT;
        }

#ifndef NDEBUG
        if ((rad_debug_lvl > 2) && fr_log_fp) {
                size_t i;

                for (i = 0; i < data_len; i++) {
                        if ((i & 0x0f) == 0) fprintf(fr_log_fp, "  TTLS tunnel data in %04x: ", (int) i);

                        fprintf(fr_log_fp, "%02x ", data[i]);

                        if ((i & 0x0f) == 0x0f) fprintf(fr_log_fp, "\n");
                }
                if ((data_len & 0x0f) != 0) fprintf(fr_log_fp, "\n");
        }
#endif

        if (!diameter_verify(request, data, data_len)) {
                return PW_CODE_ACCESS_REJECT;
        }

        /*
         *      Allocate a fake REQUEST structure.
         */
        fake = request_alloc_fake(request);

        rad_assert(!fake->packet->vps);

        /*
         *      Add the tunneled attributes to the fake request.
         */
        fake->packet->vps = diameter2vp(request, fake, tls_session->ssl, data, data_len);
        if (!fake->packet->vps) {
                talloc_free(fake);
                return PW_CODE_ACCESS_REJECT;
        }

        /*
         *      Tell the request that it's a fake one.
         */
        pair_make_request("Freeradius-Proxied-To", "127.0.0.1", T_OP_EQ);

        RDEBUG("Got tunneled request");
        rdebug_pair_list(L_DBG_LVL_1, request, fake->packet->vps, NULL);

        /*
         *      Update other items in the REQUEST data structure.
         */
        fake->username = fr_pair_find_by_num(fake->packet->vps, 0, PW_USER_NAME, TAG_ANY);
        fake->password = fr_pair_find_by_num(fake->packet->vps, 0, PW_USER_PASSWORD, TAG_ANY);

        /*
         *      No User-Name, try to create one from stored data.
         */
        if (!fake->username) {
                /*
                 *      No User-Name in the stored data, look for
                 *      an EAP-Identity, and pull it out of there.
                 */
                if (!t->username) {
                        vp = fr_pair_find_by_num(fake->packet->vps, 0, PW_EAP_MESSAGE, TAG_ANY);
                        if (vp &&
                            (vp->vp_length >= EAP_HEADER_LEN + 2) &&
                            (vp->vp_strvalue[0] == PW_EAP_RESPONSE) &&
                            (vp->vp_strvalue[EAP_HEADER_LEN] == PW_EAP_IDENTITY) &&
                            (vp->vp_strvalue[EAP_HEADER_LEN + 1] != 0)) {
                                /*
                                 *      Create & remember a User-Name
                                 */
                                t->username = fr_pair_make(t, NULL, "User-Name", NULL, T_OP_EQ);
                                rad_assert(t->username != NULL);

                                fr_pair_value_bstrncpy(t->username, vp->vp_octets + 5, vp->vp_length - 5);

                                RDEBUG("Got tunneled identity of %s",
                                       t->username->vp_strvalue);

                                /*
                                 *      If there's a default EAP type,
                                 *      set it here.
                                 */
                                if (t->default_method != 0) {
                                        RDEBUG("Setting default EAP type for tunneled EAP session");
                                        vp = fr_pair_afrom_num(fake, 0, PW_EAP_TYPE);
                                        rad_assert(vp != NULL);
                                        vp->vp_integer = t->default_method;
                                        fr_pair_add(&fake->config, vp);
                                }

                        } else {
                                /*
                                 *      Don't reject the request outright,
                                 *      as it's permitted to do EAP without
                                 *      user-name.
                                 */
                                RWDEBUG2("No EAP-Identity found to start EAP conversation");
                        }
                } /* else there WAS a t->username */

                if (t->username) {
                        vp = fr_pair_list_copy(fake->packet, t->username);
                        fr_pair_add(&fake->packet->vps, vp);
                        fake->username = fr_pair_find_by_num(fake->packet->vps, 0, PW_USER_NAME, TAG_ANY);
                }
        } /* else the request ALREADY had a User-Name */

        /*
         *      Add the State attribute, too, if it exists.
         */
        if (t->state) {
                vp = fr_pair_list_copy(fake->packet, t->state);
                if (vp) fr_pair_add(&fake->packet->vps, vp);
        }

        /*
         *      If this is set, we copy SOME of the request attributes
         *      from outside of the tunnel to inside of the tunnel.
         *
         *      We copy ONLY those attributes which do NOT already
         *      exist in the tunneled request.
         */
        if (t->copy_request_to_tunnel) {
                VALUE_PAIR *copy;
                vp_cursor_t cursor;

                for (vp = fr_cursor_init(&cursor, &request->packet->vps); vp; vp = fr_cursor_next(&cursor)) {
                        /*
                         *      The attribute is a server-side thingy,
                         *      don't copy it.
                         */
                        if ((vp->da->attr > 255) &&
                            (vp->da->vendor == 0)) {
                                continue;
                        }

                        /*
                         *      The outside attribute is already in the
                         *      tunnel, don't copy it.
                         *
                         *      This works for BOTH attributes which
                         *      are originally in the tunneled request,
                         *      AND attributes which are copied there
                         *      from below.
                         */
                        if (fr_pair_find_by_da(fake->packet->vps, vp->da, TAG_ANY)) {
                                continue;
                        }

                        /*
                         *      Some attributes are handled specially.
                         */
                        switch (vp->da->attr) {
                        /*
                         *      NEVER copy Message-Authenticator,
                         *      EAP-Message, or State.  They're
                         *      only for outside of the tunnel.
                         */
                        case PW_USER_NAME:
                        case PW_USER_PASSWORD:
                        case PW_CHAP_PASSWORD:
                        case PW_CHAP_CHALLENGE:
                        case PW_PROXY_STATE:
                        case PW_MESSAGE_AUTHENTICATOR:
                        case PW_EAP_MESSAGE:
                        case PW_STATE:
                                continue;

                        /*
                         *      By default, copy it over.
                         */
                        default:
                                break;
                        }

                        /*
                         *      Don't copy from the head, we've already
                         *      checked it.
                         */
                        copy = fr_pair_list_copy_by_num(fake->packet, vp, vp->da->vendor, vp->da->attr, TAG_ANY);
                        fr_pair_add(&fake->packet->vps, copy);
                }
        }

        /*
         *      Process channel binding.
         */
        chbind = eap_chbind_vp2packet(fake, fake->packet->vps);
        if (chbind) {
                PW_CODE chbind_code;
                CHBIND_REQ *req = talloc_zero(fake, CHBIND_REQ);

                RDEBUG("received chbind request");
                req->request = chbind;
                if (fake->username) {
                        req->username = fake->username;
                } else {
                        req->username = NULL;
                }
                chbind_code = chbind_process(request, req);

                /* encapsulate response here */
                if (req->response) {
                        RDEBUG("sending chbind response");
                        fr_pair_add(&fake->reply->vps,
                                eap_chbind_packet2vp(fake, req->response));
                } else {
                        RDEBUG("no chbind response");
                }

                /* clean up chbind req */
                talloc_free(req);

                if (chbind_code != PW_CODE_ACCESS_ACCEPT) {
                        return chbind_code;
                }
        }

        /*
         *      Call authentication recursively, which will
         *      do PAP, CHAP, MS-CHAP, etc.
         */
        eap_virtual_server(request, fake, eap_session, t->virtual_server);

        /*
         *      Decide what to do with the reply.
         */
        switch (fake->reply->code) {
        case 0:                 /* No reply code, must be proxied... */
#ifdef WITH_PROXY
                vp = fr_pair_find_by_num(fake->config, 0, PW_PROXY_TO_REALM, TAG_ANY);
                if (vp) {
                        eap_tunnel_data_t *tunnel;
                        RDEBUG("Tunneled authentication will be proxied to %s", vp->vp_strvalue);

                        /*
                         *      Tell the original request that it's going
                         *      to be proxied.
                         */
                        fr_pair_list_mcopy_by_num(request, &request->config, &fake->config, 0, PW_PROXY_TO_REALM,
                                                  TAG_ANY);

                        /*
                         *      Seed the proxy packet with the
                         *      tunneled request.
                         */
                        rad_assert(!request->proxy);
                        request->proxy = talloc_steal(request, fake->packet);
                        memset(&request->proxy->src_ipaddr, 0,
                               sizeof(request->proxy->src_ipaddr));
                        memset(&request->proxy->src_ipaddr, 0,
                               sizeof(request->proxy->src_ipaddr));
                        request->proxy->src_port = 0;
                        request->proxy->dst_port = 0;
                        fake->packet = NULL;
                        fr_radius_free(&fake->reply);
                        fake->reply = NULL;

                        /*
                         *      Set up the callbacks for the tunnel
                         */
                        tunnel = talloc_zero(request, eap_tunnel_data_t);
                        tunnel->tls_session = tls_session;
                        tunnel->callback = eap_ttls_postproxy;

                        /*
                         *      Associate the callback with the request.
                         */
                        code = request_data_add(request, request->proxy, REQUEST_DATA_EAP_TUNNEL_CALLBACK,
                                                tunnel, false, false, false);
                        rad_assert(code == 0);

                        /*
                         *      rlm_eap.c has taken care of associating
                         *      the eap_session with the fake request.
                         *
                         *      So we associate the fake request with
                         *      this request.
                         */
                        code = request_data_add(request, request->proxy, REQUEST_DATA_EAP_MSCHAP_TUNNEL_CALLBACK,
                                                fake, true, false, false);
                        rad_assert(code == 0);
                        fake = NULL;

                        /*
                         *      Didn't authenticate the packet, but
                         *      we're proxying it.
                         */
                        code = PW_CODE_STATUS_CLIENT;

                } else
#endif  /* WITH_PROXY */
                  {
                        RDEBUG("No tunneled reply was found for request %d , and the request was not proxied: rejecting the user.",
                               request->number);
                        code = PW_CODE_ACCESS_REJECT;
                }
                break;

        default:
                /*
                 *      Returns RLM_MODULE_FOO, and we want to return PW_FOO
                 */
                rcode = process_reply(eap_session, tls_session, request, fake->reply);
                switch (rcode) {
                case RLM_MODULE_REJECT:
                        code = PW_CODE_ACCESS_REJECT;
                        break;

                case RLM_MODULE_HANDLED:
                        code = PW_CODE_ACCESS_CHALLENGE;
                        break;

                case RLM_MODULE_OK:
                        code = PW_CODE_ACCESS_ACCEPT;
                        break;

                default:
                        code = PW_CODE_ACCESS_REJECT;
                        break;
                }
                break;
        }

        talloc_free(fake);

        return code;
}