s3-dcerpc: rationalize packet creation in the server code

[Samba.git] / source3 / rpc_server / srv_pipe.c

/* 
 *  Unix SMB/CIFS implementation.
 *  RPC Pipe client / server routines
 *  Almost completely rewritten by (C) Jeremy Allison 2005 - 2010
 *  
 *  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 3 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, see <http://www.gnu.org/licenses/>.
 */

/*  this module apparently provides an implementation of DCE/RPC over a
 *  named pipe (IPC$ connection using SMBtrans).  details of DCE/RPC
 *  documentation are available (in on-line form) from the X-Open group.
 *
 *  this module should provide a level of abstraction between SMB
 *  and DCE/RPC, while minimising the amount of mallocs, unnecessary
 *  data copies, and network traffic.
 *
 */

#include "includes.h"
#include "srv_pipe_internal.h"
#include "../librpc/gen_ndr/ndr_schannel.h"
#include "../libcli/auth/schannel.h"
#include "../libcli/auth/spnego.h"
#include "../libcli/auth/ntlmssp.h"
#include "ntlmssp_wrap.h"
#include "rpc_server.h"

#undef DBGC_CLASS
#define DBGC_CLASS DBGC_RPC_SRV

/**
 * Dump everything from the start of the end up of the provided data
 * into a file, but only at debug level >= 50
 **/
static void dump_pdu_region(const char *name, int v,
                            DATA_BLOB *data, size_t start, size_t end)
{
        int fd, i;
        char *fname = NULL;
        ssize_t sz;

        if (DEBUGLEVEL < 50) return;

        if (start > data->length || end > data->length || start > end) return;

        for (i = 1; i < 100; i++) {
                if (v != -1) {
                        fname = talloc_asprintf(talloc_tos(),
                                                "/tmp/%s_%d.%d.prs",
                                                name, v, i);
                } else {
                        fname = talloc_asprintf(talloc_tos(),
                                                "/tmp/%s_%d.prs",
                                                name, i);
                }
                if (!fname) {
                        return;
                }
                fd = open(fname, O_WRONLY|O_CREAT|O_EXCL, 0644);
                if (fd != -1 || errno != EEXIST) break;
        }
        if (fd != -1) {
                sz = write(fd, data->data + start, end - start);
                i = close(fd);
                if ((sz != end - start) || (i != 0) ) {
                        DEBUG(0, ("Error writing/closing %s: %ld!=%ld %d\n",
                                  fname, (unsigned long)sz,
                                  (unsigned long)end - start, i));
                } else {
                        DEBUG(0,("created %s\n", fname));
                }
        }
        TALLOC_FREE(fname);
}

static void free_pipe_ntlmssp_auth_data(struct pipe_auth_data *auth)
{
        TALLOC_FREE(auth->a_u.auth_ntlmssp_state);
}

static void free_pipe_schannel_auth_data(struct pipe_auth_data *auth)
{
        TALLOC_FREE(auth->a_u.schannel_auth);
}

static void free_pipe_auth_data(struct pipe_auth_data *auth)
{
        if (auth->auth_data_free_func) {
                (*auth->auth_data_free_func)(auth);
                auth->auth_data_free_func = NULL;
        }
}

static DATA_BLOB generic_session_key(void)
{
        return data_blob("SystemLibraryDTC", 16);
}

/*******************************************************************
 Generate the next PDU to be returned from the data.
********************************************************************/

static bool create_next_packet(TALLOC_CTX *mem_ctx,
                                struct pipe_auth_data *auth,
                                uint32_t call_id,
                                DATA_BLOB *rdata,
                                size_t data_sent_length,
                                DATA_BLOB *frag,
                                size_t *pdu_size)
{
        union dcerpc_payload u;
        uint8_t pfc_flags;
        size_t data_len_left;
        size_t data_len;
        size_t max_len;
        size_t pad_len = 0;
        size_t auth_len = 0;
        NTSTATUS status;

        switch (auth->auth_level) {
        case DCERPC_AUTH_LEVEL_NONE:
        case DCERPC_AUTH_LEVEL_CONNECT:
                /* This is incorrect for auth level connect. Fixme. JRA */

                /* No authentication done. */
                break;

        case DCERPC_AUTH_LEVEL_CALL:
        case DCERPC_AUTH_LEVEL_PACKET:
        case DCERPC_AUTH_LEVEL_INTEGRITY:
        case DCERPC_AUTH_LEVEL_PRIVACY:

                switch(auth->auth_type) {
                case DCERPC_AUTH_TYPE_NTLMSSP:
                        auth_len = NTLMSSP_SIG_SIZE;
                        break;
                case DCERPC_AUTH_TYPE_SPNEGO:
                        if (auth->spnego_type !=
                                        PIPE_AUTH_TYPE_SPNEGO_NTLMSSP) {
                                return false;
                        }
                        auth_len = NTLMSSP_SIG_SIZE;
                        break;

                case DCERPC_AUTH_TYPE_SCHANNEL:
                        auth_len = NL_AUTH_SIGNATURE_SIZE;
                        break;

                default:
                        return false;
                }

                break;

        default:
                return false;
        }

        ZERO_STRUCT(u.response);

        /* Set up rpc packet pfc flags. */
        if (data_sent_length == 0) {
                pfc_flags = DCERPC_PFC_FLAG_FIRST;
        } else {
                pfc_flags = 0;
        }

        /* Work out how much we can fit in a single PDU. */
        data_len_left = rdata->length - data_sent_length;

        /* Ensure there really is data left to send. */
        if (!data_len_left) {
                DEBUG(0, ("No data left to send !\n"));
                return false;
        }

        /* Max space available - not including padding. */
        if (auth_len) {
                max_len = RPC_MAX_PDU_FRAG_LEN
                                - DCERPC_RESPONSE_LENGTH
                                - DCERPC_AUTH_TRAILER_LENGTH
                                - auth_len;
        } else {
                max_len = RPC_MAX_PDU_FRAG_LEN - DCERPC_RESPONSE_LENGTH;
        }

        /*
         * The amount we send is the minimum of the max_len
         * and the amount left to send.
         */
        data_len = MIN(data_len_left, max_len);

        if (auth_len) {
                /* Work out any padding alignment requirements. */
                pad_len = (DCERPC_RESPONSE_LENGTH + data_len) %
                                                SERVER_NDR_PADDING_SIZE;
                if (pad_len) {
                        pad_len = SERVER_NDR_PADDING_SIZE - pad_len;
                        DEBUG(10, ("Padding size is: %d\n", (int)pad_len));
                        /* If we're over filling the packet, we need to make
                         * space for the padding at the end of the data. */
                        if (data_len + pad_len > max_len) {
                                data_len -= SERVER_NDR_PADDING_SIZE;
                        }
                }
        }

        /* Set up the alloc hint. This should be the data left to send. */
        u.response.alloc_hint = data_len_left;

        /* Work out if this PDU will be the last. */
        if (data_sent_length + data_len >= rdata->length) {
                pfc_flags |= DCERPC_PFC_FLAG_LAST;
        }

        /* Prepare data to be NDR encoded. */
        u.response.stub_and_verifier =
                data_blob_const(rdata->data + data_sent_length, data_len);

        /* Store the packet in the data stream. */
        status = dcerpc_push_ncacn_packet(mem_ctx, DCERPC_PKT_RESPONSE,
                                          pfc_flags, auth_len, call_id,
                                          &u, frag);
        if (!NT_STATUS_IS_OK(status)) {
                DEBUG(0, ("Failed to marshall RPC Packet.\n"));
                return false;
        }

        if (auth_len) {
                /* Set the proper length on the pdu, including padding.
                 * Only needed if an auth trailer will be appended. */
                dcerpc_set_frag_length(frag, frag->length
                                                + pad_len
                                                + DCERPC_AUTH_TRAILER_LENGTH
                                                + auth_len);
        }

        if (auth_len) {
                status = dcerpc_add_auth_footer(auth, pad_len, frag);
                if (!NT_STATUS_IS_OK(status)) {
                        data_blob_free(frag);
                        return false;
                }
        }

        *pdu_size = data_len;
        return true;
}

/*******************************************************************
 Generate the next PDU to be returned from the data in p->rdata. 
********************************************************************/

bool create_next_pdu(struct pipes_struct *p)
{
        size_t pdu_size;
        bool ret;

        /*
         * If we're in the fault state, keep returning fault PDU's until
         * the pipe gets closed. JRA.
         */
        if (p->fault_state) {
                setup_fault_pdu(p, NT_STATUS(DCERPC_FAULT_OP_RNG_ERROR));
                return true;
        }

        ret = create_next_packet(p->mem_ctx, &p->auth, p->call_id,
                                 &p->out_data.rdata,
                                 p->out_data.data_sent_length,
                                 &p->out_data.frag, &pdu_size);
        if (!ret) {
                DEBUG(0, ("Invalid internal auth level %u / type %u\n",
                          (unsigned int)p->auth.auth_level,
                          (unsigned int)p->auth.auth_type));
                return false;
        }

        /* Setup the counts for this PDU. */
        p->out_data.data_sent_length += pdu_size;
        p->out_data.current_pdu_sent = 0;
        return true;
}

/*******************************************************************
 Process an NTLMSSP authentication response.
 If this function succeeds, the user has been authenticated
 and their domain, name and calling workstation stored in
 the pipe struct.
*******************************************************************/

static bool pipe_ntlmssp_verify_final(struct pipes_struct *p,
                                      DATA_BLOB *p_resp_blob)
{
        DATA_BLOB session_key, reply;
        NTSTATUS status;
        struct auth_ntlmssp_state *a = p->auth.a_u.auth_ntlmssp_state;
        bool ret;

        DEBUG(5,("pipe_ntlmssp_verify_final: pipe %s checking user details\n",
                 get_pipe_name_from_syntax(talloc_tos(), &p->syntax)));

        ZERO_STRUCT(reply);

        /* this has to be done as root in order to verify the password */
        become_root();
        status = auth_ntlmssp_update(a, *p_resp_blob, &reply);
        unbecome_root();

        /* Don't generate a reply. */
        data_blob_free(&reply);

        if (!NT_STATUS_IS_OK(status)) {
                return False;
        }

        /* Finally - if the pipe negotiated integrity (sign) or privacy (seal)
           ensure the underlying NTLMSSP flags are also set. If not we should
           refuse the bind. */

        if (p->auth.auth_level == DCERPC_AUTH_LEVEL_INTEGRITY) {
                if (!auth_ntlmssp_negotiated_sign(a)) {
                        DEBUG(0,("pipe_ntlmssp_verify_final: pipe %s : packet integrity requested "
                                "but client declined signing.\n",
                                 get_pipe_name_from_syntax(talloc_tos(),
                                                           &p->syntax)));
                        return False;
                }
        }
        if (p->auth.auth_level == DCERPC_AUTH_LEVEL_PRIVACY) {
                if (!auth_ntlmssp_negotiated_seal(a)) {
                        DEBUG(0,("pipe_ntlmssp_verify_final: pipe %s : packet privacy requested "
                                "but client declined sealing.\n",
                                 get_pipe_name_from_syntax(talloc_tos(),
                                                           &p->syntax)));
                        return False;
                }
        }

        DEBUG(5, ("pipe_ntlmssp_verify_final: OK: user: %s domain: %s "
                  "workstation: %s\n",
                  auth_ntlmssp_get_username(a),
                  auth_ntlmssp_get_domain(a),
                  auth_ntlmssp_get_client(a)));

        TALLOC_FREE(p->server_info);

        status = auth_ntlmssp_steal_server_info(p, a, &p->server_info);
        if (!NT_STATUS_IS_OK(status)) {
                DEBUG(0, ("auth_ntlmssp_server_info failed to obtain the server info for authenticated user: %s\n",
                          nt_errstr(status)));
                return false;
        }

        if (p->server_info->ptok == NULL) {
                DEBUG(1,("Error: Authmodule failed to provide nt_user_token\n"));
                return False;
        }

        /*
         * We're an authenticated bind over smb, so the session key needs to
         * be set to "SystemLibraryDTC". Weird, but this is what Windows
         * does. See the RPC-SAMBA3SESSIONKEY.
         */

        session_key = generic_session_key();
        if (session_key.data == NULL) {
                return False;
        }

        ret = server_info_set_session_key(p->server_info, session_key);

        data_blob_free(&session_key);

        return True;
}

/*******************************************************************
 This is the "stage3" NTLMSSP response after a bind request and reply.
*******************************************************************/

bool api_pipe_bind_auth3(struct pipes_struct *p, struct ncacn_packet *pkt)
{
        struct dcerpc_auth auth_info;
        NTSTATUS status;

        DEBUG(5, ("api_pipe_bind_auth3: decode request. %d\n", __LINE__));

        if (pkt->auth_length == 0) {
                DEBUG(0, ("No auth field sent for bind request!\n"));
                goto err;
        }

        /* Ensure there's enough data for an authenticated request. */
        if (pkt->frag_length < RPC_HEADER_LEN
                                + DCERPC_AUTH_TRAILER_LENGTH
                                + pkt->auth_length) {
                        DEBUG(0,("api_pipe_ntlmssp_auth_process: auth_len "
                                "%u is too large.\n",
                        (unsigned int)pkt->auth_length));
                goto err;
        }

        /*
         * Decode the authentication verifier response.
         */

        status = dcerpc_pull_dcerpc_auth(pkt,
                                         &pkt->u.auth3.auth_info,
                                         &auth_info, p->endian);
        if (!NT_STATUS_IS_OK(status)) {
                DEBUG(0, ("Failed to unmarshall dcerpc_auth.\n"));
                goto err;
        }

        /* We must NEVER look at auth_info->auth_pad_len here,
         * as old Samba client code gets it wrong and sends it
         * as zero. JRA.
         */

        if (auth_info.auth_type != DCERPC_AUTH_TYPE_NTLMSSP) {
                DEBUG(0,("api_pipe_bind_auth3: incorrect auth type (%u).\n",
                        (unsigned int)auth_info.auth_type ));
                return False;
        }

        /*
         * The following call actually checks the challenge/response data.
         * for correctness against the given DOMAIN\user name.
         */

        if (!pipe_ntlmssp_verify_final(p, &auth_info.credentials)) {
                goto err;
        }

        p->pipe_bound = True;

        return True;

 err:

        free_pipe_auth_data(&p->auth);

        return False;
}

static bool pipe_init_outgoing_data(struct pipes_struct *p);

/*******************************************************************
 Marshall a bind_nak pdu.
*******************************************************************/

static bool setup_bind_nak(struct pipes_struct *p, struct ncacn_packet *pkt)
{
        NTSTATUS status;
        union dcerpc_payload u;

        /* Free any memory in the current return data buffer. */
        pipe_init_outgoing_data(p);

        /*
         * Initialize a bind_nak header.
         */

        ZERO_STRUCT(u);

        u.bind_nak.reject_reason  = 0;

        /*
         * Marshall directly into the outgoing PDU space. We
         * must do this as we need to set to the bind response
         * header and are never sending more than one PDU here.
         */

        status = dcerpc_push_ncacn_packet(p->mem_ctx,
                                          DCERPC_PKT_BIND_NAK,
                                          DCERPC_PFC_FLAG_FIRST |
                                                DCERPC_PFC_FLAG_LAST,
                                          0,
                                          pkt->call_id,
                                          &u,
                                          &p->out_data.frag);
        if (!NT_STATUS_IS_OK(status)) {
                return False;
        }

        p->out_data.data_sent_length = 0;
        p->out_data.current_pdu_sent = 0;

        free_pipe_auth_data(&p->auth);
        p->auth.auth_level = DCERPC_AUTH_LEVEL_NONE;
        p->auth.auth_type = DCERPC_AUTH_TYPE_NONE;
        p->auth.spnego_type = PIPE_AUTH_TYPE_SPNEGO_NONE;
        p->pipe_bound = False;

        return True;
}

/*******************************************************************
 Marshall a fault pdu.
*******************************************************************/

bool setup_fault_pdu(struct pipes_struct *p, NTSTATUS fault_status)
{
        NTSTATUS status;
        union dcerpc_payload u;

        /* Free any memory in the current return data buffer. */
        pipe_init_outgoing_data(p);

        /*
         * Initialize a fault header.
         */

        ZERO_STRUCT(u);

        u.fault.status          = NT_STATUS_V(fault_status);
        u.fault._pad            = data_blob_talloc_zero(p->mem_ctx, 4);

        /*
         * Marshall directly into the outgoing PDU space. We
         * must do this as we need to set to the bind response
         * header and are never sending more than one PDU here.
         */

        status = dcerpc_push_ncacn_packet(p->mem_ctx,
                                          DCERPC_PKT_FAULT,
                                          DCERPC_PFC_FLAG_FIRST |
                                           DCERPC_PFC_FLAG_LAST |
                                           DCERPC_PFC_FLAG_DID_NOT_EXECUTE,
                                          0,
                                          p->call_id,
                                          &u,
                                          &p->out_data.frag);
        if (!NT_STATUS_IS_OK(status)) {
                return False;
        }

        p->out_data.data_sent_length = 0;
        p->out_data.current_pdu_sent = 0;

        return True;
}

/*******************************************************************
 Ensure a bind request has the correct abstract & transfer interface.
 Used to reject unknown binds from Win2k.
*******************************************************************/

static bool check_bind_req(struct pipes_struct *p,
                           struct ndr_syntax_id* abstract,
                           struct ndr_syntax_id* transfer,
                           uint32 context_id)
{
        struct pipe_rpc_fns *context_fns;

        DEBUG(3,("check_bind_req for %s\n",
                 get_pipe_name_from_syntax(talloc_tos(), &p->syntax)));

        /* we have to check all now since win2k introduced a new UUID on the lsaprpc pipe */
        if (rpc_srv_pipe_exists_by_id(abstract) &&
           ndr_syntax_id_equal(transfer, &ndr_transfer_syntax)) {
                DEBUG(3, ("check_bind_req: \\PIPE\\%s -> \\PIPE\\%s\n",
                        rpc_srv_get_pipe_cli_name(abstract),
                        rpc_srv_get_pipe_srv_name(abstract)));
        } else {
                return false;
        }

        context_fns = SMB_MALLOC_P(struct pipe_rpc_fns);
        if (context_fns == NULL) {
                DEBUG(0,("check_bind_req: malloc() failed!\n"));
                return False;
        }

        context_fns->n_cmds = rpc_srv_get_pipe_num_cmds(abstract);
        context_fns->cmds = rpc_srv_get_pipe_cmds(abstract);
        context_fns->context_id = context_id;

        /* add to the list of open contexts */

        DLIST_ADD( p->contexts, context_fns );

        return True;
}

/**
 * Is a named pipe known?
 * @param[in] cli_filename      The pipe name requested by the client
 * @result                      Do we want to serve this?
 */
bool is_known_pipename(const char *cli_filename, struct ndr_syntax_id *syntax)
{
        const char *pipename = cli_filename;
        NTSTATUS status;

        if (strnequal(pipename, "\\PIPE\\", 6)) {
                pipename += 5;
        }

        if (*pipename == '\\') {
                pipename += 1;
        }

        if (lp_disable_spoolss() && strequal(pipename, "spoolss")) {
                DEBUG(10, ("refusing spoolss access\n"));
                return false;
        }

        if (rpc_srv_get_pipe_interface_by_cli_name(pipename, syntax)) {
                return true;
        }

        status = smb_probe_module("rpc", pipename);
        if (!NT_STATUS_IS_OK(status)) {
                DEBUG(10, ("is_known_pipename: %s unknown\n", cli_filename));
                return false;
        }
        DEBUG(10, ("is_known_pipename: %s loaded dynamically\n", pipename));

        /*
         * Scan the list again for the interface id
         */
        if (rpc_srv_get_pipe_interface_by_cli_name(pipename, syntax)) {
                return true;
        }

        DEBUG(10, ("is_known_pipename: pipe %s did not register itself!\n",
                   pipename));

        return false;
}

/*******************************************************************
 Handle a SPNEGO krb5 bind auth.
*******************************************************************/

static bool pipe_spnego_auth_bind_kerberos(struct pipes_struct *p,
                                           TALLOC_CTX *mem_ctx,
                                           struct dcerpc_auth *pauth_info,
                                           DATA_BLOB *psecblob,
                                           DATA_BLOB *response)
{
        return False;
}

/*******************************************************************
 Handle the first part of a SPNEGO bind auth.
*******************************************************************/

static bool pipe_spnego_auth_bind_negotiate(struct pipes_struct *p,
                                            TALLOC_CTX *mem_ctx,
                                            struct dcerpc_auth *pauth_info,
                                            DATA_BLOB *response)
{
        DATA_BLOB secblob;
        DATA_BLOB chal;
        char *OIDs[ASN1_MAX_OIDS];
        int i;
        NTSTATUS status;
        bool got_kerberos_mechanism = false;
        struct auth_ntlmssp_state *a = NULL;

        ZERO_STRUCT(secblob);
        ZERO_STRUCT(chal);

        if (pauth_info->credentials.data[0] != ASN1_APPLICATION(0)) {
                goto err;
        }

        /* parse out the OIDs and the first sec blob */
        if (!spnego_parse_negTokenInit(talloc_tos(),
                        pauth_info->credentials, OIDs, NULL, &secblob)) {
                DEBUG(0,("pipe_spnego_auth_bind_negotiate: Failed to parse the security blob.\n"));
                goto err;
        }

        if (strcmp(OID_KERBEROS5, OIDs[0]) == 0 || strcmp(OID_KERBEROS5_OLD, OIDs[0]) == 0) {
                got_kerberos_mechanism = true;
        }

        for (i=0;OIDs[i];i++) {
                DEBUG(3,("pipe_spnego_auth_bind_negotiate: Got OID %s\n", OIDs[i]));
                TALLOC_FREE(OIDs[i]);
        }
        DEBUG(3,("pipe_spnego_auth_bind_negotiate: Got secblob of size %lu\n", (unsigned long)secblob.length));

        if ( got_kerberos_mechanism && ((lp_security()==SEC_ADS) || USE_KERBEROS_KEYTAB) ) {
                bool ret;
                ret = pipe_spnego_auth_bind_kerberos(p, mem_ctx, pauth_info,
                                                     &secblob, response);
                data_blob_free(&secblob);
                return ret;
        }

        /* Free any previous auth type. */
        free_pipe_auth_data(&p->auth);

        if (!got_kerberos_mechanism) {
                /* Initialize the NTLM engine. */
                status = auth_ntlmssp_start(&a);
                if (!NT_STATUS_IS_OK(status)) {
                        goto err;
                }

                /* Clear flags,
                 * then set them according to requested Auth Level */
                auth_ntlmssp_and_flags(a, ~(NTLMSSP_NEGOTIATE_SIGN |
                                                NTLMSSP_NEGOTIATE_SEAL));
                switch (pauth_info->auth_level) {
                        case DCERPC_AUTH_LEVEL_INTEGRITY:
                                auth_ntlmssp_or_flags(a,
                                                NTLMSSP_NEGOTIATE_SIGN);
                                break;
                        case DCERPC_AUTH_LEVEL_PRIVACY:
                                /* Privacy always implies both sign and seal
                                 * for ntlmssp */
                                auth_ntlmssp_or_flags(a,
                                                NTLMSSP_NEGOTIATE_SIGN |
                                                NTLMSSP_NEGOTIATE_SEAL);
                                break;
                        default:
                                break;
                }
                /*
                 * Pass the first security blob of data to it.
                 * This can return an error or NT_STATUS_MORE_PROCESSING_REQUIRED
                 * which means we need another packet to complete the bind.
                 */

                status = auth_ntlmssp_update(a, secblob, &chal);

                if (!NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
                        DEBUG(3,("pipe_spnego_auth_bind_negotiate: auth_ntlmssp_update failed.\n"));
                        goto err;
                }

                /* Generate the response blob we need for step 2 of the bind. */
                *response = spnego_gen_auth_response(mem_ctx, &chal, status, OID_NTLMSSP);
        } else {
                /*
                 * SPNEGO negotiate down to NTLMSSP. The subsequent
                 * code to process follow-up packets is not complete
                 * yet. JRA.
                 */
                *response = spnego_gen_auth_response(mem_ctx, NULL,
                                        NT_STATUS_MORE_PROCESSING_REQUIRED,
                                        OID_NTLMSSP);
        }

        /* auth_pad_len will be handled by the caller */

        p->auth.a_u.auth_ntlmssp_state = a;
        p->auth.auth_data_free_func = &free_pipe_ntlmssp_auth_data;
        p->auth.auth_type = DCERPC_AUTH_TYPE_SPNEGO;
        p->auth.spnego_type = PIPE_AUTH_TYPE_SPNEGO_NTLMSSP;

        data_blob_free(&secblob);
        data_blob_free(&chal);

        /* We can't set pipe_bound True yet - we need an RPC_ALTER_CONTEXT response packet... */
        return True;

 err:

        data_blob_free(&secblob);
        data_blob_free(&chal);

        p->auth.a_u.auth_ntlmssp_state = NULL;

        return False;
}

/*******************************************************************
 Handle the second part of a SPNEGO bind auth.
*******************************************************************/

static bool pipe_spnego_auth_bind_continue(struct pipes_struct *p,
                                           TALLOC_CTX *mem_ctx,
                                           struct dcerpc_auth *pauth_info,
                                           DATA_BLOB *response)
{
        DATA_BLOB auth_blob;
        DATA_BLOB auth_reply;
        struct auth_ntlmssp_state *a = p->auth.a_u.auth_ntlmssp_state;

        ZERO_STRUCT(auth_blob);
        ZERO_STRUCT(auth_reply);

        /*
         * NB. If we've negotiated down from krb5 to NTLMSSP we'll currently
         * fail here as 'a' == NULL.
         */
        if (p->auth.auth_type != DCERPC_AUTH_TYPE_SPNEGO ||
            p->auth.spnego_type != PIPE_AUTH_TYPE_SPNEGO_NTLMSSP || !a) {
                DEBUG(0,("pipe_spnego_auth_bind_continue: not in NTLMSSP auth state.\n"));
                goto err;
        }

        if (pauth_info->credentials.data[0] != ASN1_CONTEXT(1)) {
                DEBUG(0,("pipe_spnego_auth_bind_continue: invalid SPNEGO blob type.\n"));
                goto err;
        }

        if (!spnego_parse_auth(talloc_tos(), pauth_info->credentials, &auth_blob)) {
                DEBUG(0,("pipe_spnego_auth_bind_continue: invalid SPNEGO blob.\n"));
                goto err;
        }

        /*
         * The following call actually checks the challenge/response data.
         * for correctness against the given DOMAIN\user name.
         */

        if (!pipe_ntlmssp_verify_final(p, &auth_blob)) {
                goto err;
        }

        data_blob_free(&auth_blob);

        /* Generate the spnego "accept completed" blob - no incoming data. */
        *response = spnego_gen_auth_response(mem_ctx, &auth_reply, NT_STATUS_OK, OID_NTLMSSP);

        data_blob_free(&auth_reply);

        p->pipe_bound = True;

        return True;

 err:

        data_blob_free(&auth_blob);
        data_blob_free(&auth_reply);

        free_pipe_auth_data(&p->auth);

        return False;
}

/*******************************************************************
 Handle an schannel bind auth.
*******************************************************************/

static bool pipe_schannel_auth_bind(struct pipes_struct *p,
                                    TALLOC_CTX *mem_ctx,
                                    struct dcerpc_auth *auth_info,
                                    DATA_BLOB *response)
{
        struct NL_AUTH_MESSAGE neg;
        struct NL_AUTH_MESSAGE reply;
        bool ret;
        NTSTATUS status;
        struct netlogon_creds_CredentialState *creds;
        DATA_BLOB session_key;
        enum ndr_err_code ndr_err;

        ndr_err = ndr_pull_struct_blob(
                        &auth_info->credentials, mem_ctx, &neg,
                        (ndr_pull_flags_fn_t)ndr_pull_NL_AUTH_MESSAGE);
        if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
                DEBUG(0,("pipe_schannel_auth_bind: Could not unmarshal SCHANNEL auth neg\n"));
                return false;
        }

        if (DEBUGLEVEL >= 10) {
                NDR_PRINT_DEBUG(NL_AUTH_MESSAGE, &neg);
        }

        if (!(neg.Flags & NL_FLAG_OEM_NETBIOS_COMPUTER_NAME)) {
                DEBUG(0,("pipe_schannel_auth_bind: Did not receive netbios computer name\n"));
                return false;
        }

        /*
         * The neg.oem_netbios_computer.a key here must match the remote computer name
         * given in the DOM_CLNT_SRV.uni_comp_name used on all netlogon pipe
         * operations that use credentials.
         */

        become_root();
        status = schannel_get_creds_state(p, lp_private_dir(),
                                            neg.oem_netbios_computer.a, &creds);
        unbecome_root();

        if (!NT_STATUS_IS_OK(status)) {
                DEBUG(0, ("pipe_schannel_auth_bind: Attempt to bind using schannel without successful serverauth2\n"));
                return False;
        }

        p->auth.a_u.schannel_auth = talloc(p, struct schannel_state);
        if (!p->auth.a_u.schannel_auth) {
                TALLOC_FREE(creds);
                return False;
        }

        p->auth.a_u.schannel_auth->state = SCHANNEL_STATE_START;
        p->auth.a_u.schannel_auth->seq_num = 0;
        p->auth.a_u.schannel_auth->initiator = false;
        p->auth.a_u.schannel_auth->creds = creds;

        /*
         * JRA. Should we also copy the schannel session key into the pipe session key p->session_key
         * here ? We do that for NTLMSSP, but the session key is already set up from the vuser
         * struct of the person who opened the pipe. I need to test this further. JRA.
         *
         * VL. As we are mapping this to guest set the generic key
         * "SystemLibraryDTC" key here. It's a bit difficult to test against
         * W2k3, as it does not allow schannel binds against SAMR and LSA
         * anymore.
         */

        session_key = generic_session_key();
        if (session_key.data == NULL) {
                DEBUG(0, ("pipe_schannel_auth_bind: Could not alloc session"
                          " key\n"));
                return false;
        }

        ret = server_info_set_session_key(p->server_info, session_key);

        data_blob_free(&session_key);

        if (!ret) {
                DEBUG(0, ("server_info_set_session_key failed\n"));
                return false;
        }

        /*** SCHANNEL verifier ***/

        reply.MessageType                       = NL_NEGOTIATE_RESPONSE;
        reply.Flags                             = 0;
        reply.Buffer.dummy                      = 5; /* ??? actually I don't think
                                                      * this has any meaning
                                                      * here - gd */

        ndr_err = ndr_push_struct_blob(response, mem_ctx, &reply,
                       (ndr_push_flags_fn_t)ndr_push_NL_AUTH_MESSAGE);
        if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
                DEBUG(0,("Failed to marshall NL_AUTH_MESSAGE.\n"));
                return false;
        }

        if (DEBUGLEVEL >= 10) {
                NDR_PRINT_DEBUG(NL_AUTH_MESSAGE, &reply);
        }

        DEBUG(10,("pipe_schannel_auth_bind: schannel auth: domain [%s] myname [%s]\n",
                neg.oem_netbios_domain.a, neg.oem_netbios_computer.a));

        /* We're finished with this bind - no more packets. */
        p->auth.auth_data_free_func = &free_pipe_schannel_auth_data;
        p->auth.auth_type = DCERPC_AUTH_TYPE_SCHANNEL;

        p->pipe_bound = True;

        return True;
}

/*******************************************************************
 Handle an NTLMSSP bind auth.
*******************************************************************/

static bool pipe_ntlmssp_auth_bind(struct pipes_struct *p,
                                   TALLOC_CTX *mem_ctx,
                                   struct dcerpc_auth *auth_info,
                                   DATA_BLOB *response)
{
        NTSTATUS status;
        struct auth_ntlmssp_state *a = NULL;

        if (strncmp((char *)auth_info->credentials.data, "NTLMSSP", 7) != 0) {
                DEBUG(0, ("Failed to read NTLMSSP in blob\n"));
                goto err;
        }

        /* We have an NTLMSSP blob. */
        status = auth_ntlmssp_start(&a);
        if (!NT_STATUS_IS_OK(status)) {
                DEBUG(0,("pipe_ntlmssp_auth_bind: auth_ntlmssp_start failed: %s\n",
                        nt_errstr(status) ));
                goto err;
        }

        /* Clear flags, then set them according to requested Auth Level */
        auth_ntlmssp_and_flags(a, ~(NTLMSSP_NEGOTIATE_SIGN |
                                        NTLMSSP_NEGOTIATE_SEAL));

        switch (auth_info->auth_level) {
        case DCERPC_AUTH_LEVEL_INTEGRITY:
                auth_ntlmssp_or_flags(a, NTLMSSP_NEGOTIATE_SIGN);
                break;
        case DCERPC_AUTH_LEVEL_PRIVACY:
                /* Privacy always implies both sign and seal for ntlmssp */
                auth_ntlmssp_or_flags(a, NTLMSSP_NEGOTIATE_SIGN |
                                         NTLMSSP_NEGOTIATE_SEAL);
                break;
        default:
                break;
        }

        status = auth_ntlmssp_update(a, auth_info->credentials, response);
        if (!NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
                DEBUG(0,("pipe_ntlmssp_auth_bind: auth_ntlmssp_update failed: %s\n",
                        nt_errstr(status) ));
                goto err;
        }

        /* Make sure data is bound to the memctx, to be freed the caller */
        talloc_steal(mem_ctx, response->data);

        p->auth.a_u.auth_ntlmssp_state = a;
        p->auth.auth_data_free_func = &free_pipe_ntlmssp_auth_data;
        p->auth.auth_type = DCERPC_AUTH_TYPE_NTLMSSP;

        DEBUG(10,("pipe_ntlmssp_auth_bind: NTLMSSP auth started\n"));

        /* We can't set pipe_bound True yet - we need an DCERPC_PKT_AUTH3 response packet... */
        return True;

  err:

        TALLOC_FREE(a);
        return False;
}

/*******************************************************************
 Respond to a pipe bind request.
*******************************************************************/

bool api_pipe_bind_req(struct pipes_struct *p, struct ncacn_packet *pkt)
{
        struct dcerpc_auth auth_info;
        uint16 assoc_gid;
        unsigned int auth_type = DCERPC_AUTH_TYPE_NONE;
        NTSTATUS status;
        struct ndr_syntax_id id;
        union dcerpc_payload u;
        struct dcerpc_ack_ctx bind_ack_ctx;
        DATA_BLOB auth_resp = data_blob_null;
        DATA_BLOB auth_blob = data_blob_null;

        /* No rebinds on a bound pipe - use alter context. */
        if (p->pipe_bound) {
                DEBUG(2,("api_pipe_bind_req: rejecting bind request on bound "
                         "pipe %s.\n",
                         get_pipe_name_from_syntax(talloc_tos(), &p->syntax)));
                return setup_bind_nak(p, pkt);
        }

        if (pkt->u.bind.num_contexts == 0) {
                DEBUG(0, ("api_pipe_bind_req: no rpc contexts around\n"));
                goto err_exit;
        }

        /*
         * Try and find the correct pipe name to ensure
         * that this is a pipe name we support.
         */
        id = pkt->u.bind.ctx_list[0].abstract_syntax;
        if (rpc_srv_pipe_exists_by_id(&id)) {
                DEBUG(3, ("api_pipe_bind_req: \\PIPE\\%s -> \\PIPE\\%s\n",
                        rpc_srv_get_pipe_cli_name(&id),
                        rpc_srv_get_pipe_srv_name(&id)));
        } else {
                status = smb_probe_module(
                        "rpc", get_pipe_name_from_syntax(
                                talloc_tos(),
                                &pkt->u.bind.ctx_list[0].abstract_syntax));

                if (NT_STATUS_IS_ERR(status)) {
                       DEBUG(3,("api_pipe_bind_req: Unknown pipe name %s in bind request.\n",
                                get_pipe_name_from_syntax(
                                        talloc_tos(),
                                        &pkt->u.bind.ctx_list[0].abstract_syntax)));

                        return setup_bind_nak(p, pkt);
                }

                if (rpc_srv_get_pipe_interface_by_cli_name(
                                get_pipe_name_from_syntax(talloc_tos(),
                                                          &p->syntax),
                                &id)) {
                        DEBUG(3, ("api_pipe_bind_req: \\PIPE\\%s -> \\PIPE\\%s\n",
                                rpc_srv_get_pipe_cli_name(&id),
                                rpc_srv_get_pipe_srv_name(&id)));
                } else {
                        DEBUG(0, ("module %s doesn't provide functions for "
                                  "pipe %s!\n",
                                  get_pipe_name_from_syntax(talloc_tos(),
                                                            &p->syntax),
                                  get_pipe_name_from_syntax(talloc_tos(),
                                                            &p->syntax)));
                        return setup_bind_nak(p, pkt);
                }
        }

        DEBUG(5,("api_pipe_bind_req: make response. %d\n", __LINE__));

        if (pkt->u.bind.assoc_group_id != 0) {
                assoc_gid = pkt->u.bind.assoc_group_id;
        } else {
                assoc_gid = 0x53f0;
        }

        /*
         * Create the bind response struct.
         */

        /* If the requested abstract synt uuid doesn't match our client pipe,
                reject the bind_ack & set the transfer interface synt to all 0's,
                ver 0 (observed when NT5 attempts to bind to abstract interfaces
                unknown to NT4)
                Needed when adding entries to a DACL from NT5 - SK */

        if (check_bind_req(p,
                        &pkt->u.bind.ctx_list[0].abstract_syntax,
                        &pkt->u.bind.ctx_list[0].transfer_syntaxes[0],
                        pkt->u.bind.ctx_list[0].context_id)) {

                bind_ack_ctx.result = 0;
                bind_ack_ctx.reason = 0;
                bind_ack_ctx.syntax = pkt->u.bind.ctx_list[0].transfer_syntaxes[0];
        } else {
                p->pipe_bound = False;
                /* Rejection reason: abstract syntax not supported */
                bind_ack_ctx.result = DCERPC_BIND_PROVIDER_REJECT;
                bind_ack_ctx.reason = DCERPC_BIND_REASON_ASYNTAX;
                bind_ack_ctx.syntax = null_ndr_syntax_id;
        }

        /*
         * Check if this is an authenticated bind request.
         */
        if (pkt->auth_length) {
                /* Quick length check. Won't catch a bad auth footer,
                 * prevents overrun. */

                if (pkt->frag_length < RPC_HEADER_LEN +
                                        DCERPC_AUTH_TRAILER_LENGTH +
                                        pkt->auth_length) {
                        DEBUG(0,("api_pipe_bind_req: auth_len (%u) "
                                "too long for fragment %u.\n",
                                (unsigned int)pkt->auth_length,
                                (unsigned int)pkt->frag_length));
                        goto err_exit;
                }

                /*
                 * Decode the authentication verifier.
                 */
                status = dcerpc_pull_dcerpc_auth(pkt,
                                                 &pkt->u.bind.auth_info,
                                                 &auth_info, p->endian);
                if (!NT_STATUS_IS_OK(status)) {
                        DEBUG(0, ("Unable to unmarshall dcerpc_auth.\n"));
                        goto err_exit;
                }

                auth_type = auth_info.auth_type;

                /* Work out if we have to sign or seal etc. */
                switch (auth_info.auth_level) {
                case DCERPC_AUTH_LEVEL_INTEGRITY:
                        p->auth.auth_level = DCERPC_AUTH_LEVEL_INTEGRITY;
                        break;
                case DCERPC_AUTH_LEVEL_PRIVACY:
                        p->auth.auth_level = DCERPC_AUTH_LEVEL_PRIVACY;
                        break;
                default:
                        DEBUG(0, ("Unexpected auth level (%u).\n",
                                (unsigned int)auth_info.auth_level ));
                        goto err_exit;
                }

                switch (auth_type) {
                case DCERPC_AUTH_TYPE_NTLMSSP:
                        if (!pipe_ntlmssp_auth_bind(p, pkt,
                                                &auth_info, &auth_resp)) {
                                goto err_exit;
                        }
                        assoc_gid = 0x7a77;
                        break;

                case DCERPC_AUTH_TYPE_SCHANNEL:
                        if (!pipe_schannel_auth_bind(p, pkt,
                                                &auth_info, &auth_resp)) {
                                goto err_exit;
                        }
                        break;

                case DCERPC_AUTH_TYPE_SPNEGO:
                        if (!pipe_spnego_auth_bind_negotiate(p, pkt,
                                                &auth_info, &auth_resp)) {
                                goto err_exit;
                        }
                        break;

                case DCERPC_AUTH_TYPE_NONE:
                        break;

                default:
                        DEBUG(0, ("Unknown auth type %x requested.\n", auth_type));
                        goto err_exit;
                }
        }

        if (auth_type == DCERPC_AUTH_TYPE_NONE) {
                /* Unauthenticated bind request. */
                /* We're finished - no more packets. */
                p->auth.auth_type = DCERPC_AUTH_TYPE_NONE;
                p->auth.spnego_type = PIPE_AUTH_TYPE_SPNEGO_NONE;
                /* We must set the pipe auth_level here also. */
                p->auth.auth_level = DCERPC_AUTH_LEVEL_NONE;
                p->pipe_bound = True;
                /* The session key was initialized from the SMB
                 * session in make_internal_rpc_pipe_p */
        }

        ZERO_STRUCT(u.bind_ack);
        u.bind_ack.max_xmit_frag = RPC_MAX_PDU_FRAG_LEN;
        u.bind_ack.max_recv_frag = RPC_MAX_PDU_FRAG_LEN;
        u.bind_ack.assoc_group_id = assoc_gid;

        /* name has to be \PIPE\xxxxx */
        u.bind_ack.secondary_address =
                        talloc_asprintf(pkt, "\\PIPE\\%s",
                                        rpc_srv_get_pipe_srv_name(&id));
        if (!u.bind_ack.secondary_address) {
                DEBUG(0, ("Out of memory!\n"));
                goto err_exit;
        }
        u.bind_ack.secondary_address_size =
                                strlen(u.bind_ack.secondary_address) + 1;

        u.bind_ack.num_results = 1;
        u.bind_ack.ctx_list = &bind_ack_ctx;

        /* NOTE: We leave the auth_info empty so we can calculate the padding
         * later and then append the auth_info --simo */

        /*
         * Marshall directly into the outgoing PDU space. We
         * must do this as we need to set to the bind response
         * header and are never sending more than one PDU here.
         */

        status = dcerpc_push_ncacn_packet(p->mem_ctx,
                                          DCERPC_PKT_BIND_ACK,
                                          DCERPC_PFC_FLAG_FIRST |
                                                DCERPC_PFC_FLAG_LAST,
                                          auth_resp.length,
                                          pkt->call_id,
                                          &u,
                                          &p->out_data.frag);
        if (!NT_STATUS_IS_OK(status)) {
                DEBUG(0, ("Failed to marshall bind_ack packet. (%s)\n",
                          nt_errstr(status)));
        }

        if (auth_resp.length) {

                status = dcerpc_push_dcerpc_auth(pkt,
                                                 auth_type,
                                                 auth_info.auth_level,
                                                 0,
                                                 1, /* auth_context_id */
                                                 &auth_resp,
                                                 &auth_blob);
                if (!NT_STATUS_IS_OK(status)) {
                        DEBUG(0, ("Marshalling of dcerpc_auth failed.\n"));
                        goto err_exit;
                }
        }

        /* Now that we have the auth len store it into the right place in
         * the dcerpc header */
        dcerpc_set_frag_length(&p->out_data.frag,
                                p->out_data.frag.length + auth_blob.length);

        if (auth_blob.length) {

                if (!data_blob_append(p->mem_ctx, &p->out_data.frag,
                                        auth_blob.data, auth_blob.length)) {
                        DEBUG(0, ("Append of auth info failed.\n"));
                        goto err_exit;
                }
        }

        /*
         * Setup the lengths for the initial reply.
         */

        p->out_data.data_sent_length = 0;
        p->out_data.current_pdu_sent = 0;

        TALLOC_FREE(auth_blob.data);
        return True;

  err_exit:

        data_blob_free(&p->out_data.frag);
        TALLOC_FREE(auth_blob.data);
        return setup_bind_nak(p, pkt);
}

/****************************************************************************
 Deal with an alter context call. Can be third part of 3 leg auth request for
 SPNEGO calls.
****************************************************************************/

bool api_pipe_alter_context(struct pipes_struct *p, struct ncacn_packet *pkt)
{
        struct dcerpc_auth auth_info;
        uint16 assoc_gid;
        NTSTATUS status;
        union dcerpc_payload u;
        struct dcerpc_ack_ctx bind_ack_ctx;
        DATA_BLOB auth_resp = data_blob_null;
        DATA_BLOB auth_blob = data_blob_null;
        int pad_len = 0;

        DEBUG(5,("api_pipe_alter_context: make response. %d\n", __LINE__));

        if (pkt->u.bind.assoc_group_id != 0) {
                assoc_gid = pkt->u.bind.assoc_group_id;
        } else {
                assoc_gid = 0x53f0;
        }

        /*
         * Create the bind response struct.
         */

        /* If the requested abstract synt uuid doesn't match our client pipe,
                reject the bind_ack & set the transfer interface synt to all 0's,
                ver 0 (observed when NT5 attempts to bind to abstract interfaces
                unknown to NT4)
                Needed when adding entries to a DACL from NT5 - SK */

        if (check_bind_req(p,
                        &pkt->u.bind.ctx_list[0].abstract_syntax,
                        &pkt->u.bind.ctx_list[0].transfer_syntaxes[0],
                        pkt->u.bind.ctx_list[0].context_id)) {

                bind_ack_ctx.result = 0;
                bind_ack_ctx.reason = 0;
                bind_ack_ctx.syntax = pkt->u.bind.ctx_list[0].transfer_syntaxes[0];
        } else {
                p->pipe_bound = False;
                /* Rejection reason: abstract syntax not supported */
                bind_ack_ctx.result = DCERPC_BIND_PROVIDER_REJECT;
                bind_ack_ctx.reason = DCERPC_BIND_REASON_ASYNTAX;
                bind_ack_ctx.syntax = null_ndr_syntax_id;
        }

        /*
         * Check if this is an authenticated alter context request.
         */
        if (pkt->auth_length) {
                /* Quick length check. Won't catch a bad auth footer,
                 * prevents overrun. */

                if (pkt->frag_length < RPC_HEADER_LEN +
                                        DCERPC_AUTH_TRAILER_LENGTH +
                                        pkt->auth_length) {
                        DEBUG(0,("api_pipe_alter_context: auth_len (%u) "
                                "too long for fragment %u.\n",
                                (unsigned int)pkt->auth_length,
                                (unsigned int)pkt->frag_length ));
                        goto err_exit;
                }

                status = dcerpc_pull_dcerpc_auth(pkt,
                                                 &pkt->u.bind.auth_info,
                                                 &auth_info, p->endian);
                if (!NT_STATUS_IS_OK(status)) {
                        DEBUG(0, ("Unable to unmarshall dcerpc_auth.\n"));
                        goto err_exit;
                }


                /*
                 * Currently only the SPNEGO auth type uses the alter ctx
                 * response in place of the NTLMSSP auth3 type.
                 */

                if (auth_info.auth_type == DCERPC_AUTH_TYPE_SPNEGO) {
                        /* We can only finish if the pipe is unbound. */
                        if (!p->pipe_bound) {
                                if (!pipe_spnego_auth_bind_continue(p, pkt,
                                                &auth_info, &auth_resp)) {
                                        goto err_exit;
                                }

                        } else {
                                goto err_exit;
                        }
                }
        }

        ZERO_STRUCT(u.alter_resp);
        u.alter_resp.max_xmit_frag = RPC_MAX_PDU_FRAG_LEN;
        u.alter_resp.max_recv_frag = RPC_MAX_PDU_FRAG_LEN;
        u.alter_resp.assoc_group_id = assoc_gid;

        /* secondary address CAN be NULL
         * as the specs say it's ignored.
         * It MUST be NULL to have the spoolss working.
         */
        u.alter_resp.secondary_address = "";
        u.alter_resp.secondary_address_size = 1;

        u.alter_resp.num_results = 1;
        u.alter_resp.ctx_list = &bind_ack_ctx;

        /* NOTE: We leave the auth_info empty so we can calculate the padding
         * later and then append the auth_info --simo */

        /*
         * Marshall directly into the outgoing PDU space. We
         * must do this as we need to set to the bind response
         * header and are never sending more than one PDU here.
         */

        status = dcerpc_push_ncacn_packet(p->mem_ctx,
                                          DCERPC_PKT_ALTER_RESP,
                                          DCERPC_PFC_FLAG_FIRST |
                                                DCERPC_PFC_FLAG_LAST,
                                          auth_resp.length,
                                          pkt->call_id,
                                          &u,
                                          &p->out_data.frag);
        if (!NT_STATUS_IS_OK(status)) {
                DEBUG(0, ("Failed to marshall bind_ack packet. (%s)\n",
                          nt_errstr(status)));
        }

        if (auth_resp.length) {

                /* Work out any padding needed before the auth footer. */
                pad_len = p->out_data.frag.length % SERVER_NDR_PADDING_SIZE;
                if (pad_len) {
                        pad_len = SERVER_NDR_PADDING_SIZE - pad_len;
                        DEBUG(10, ("auth pad_len = %u\n",
                                   (unsigned int)pad_len));
                }

                status = dcerpc_push_dcerpc_auth(pkt,
                                                 auth_info.auth_type,
                                                 auth_info.auth_level,
                                                 pad_len,
                                                 1, /* auth_context_id */
                                                 &auth_resp,
                                                 &auth_blob);
                if (!NT_STATUS_IS_OK(status)) {
                        DEBUG(0, ("Marshalling of dcerpc_auth failed.\n"));
                        goto err_exit;
                }
        }

        /* Now that we have the auth len store it into the right place in
         * the dcerpc header */
        dcerpc_set_frag_length(&p->out_data.frag,
                                p->out_data.frag.length +
                                        pad_len + auth_blob.length);

        if (auth_resp.length) {
                if (pad_len) {
                        char pad[SERVER_NDR_PADDING_SIZE];
                        memset(pad, '\0', SERVER_NDR_PADDING_SIZE);
                        if (!data_blob_append(p->mem_ctx,
                                                &p->out_data.frag,
                                                pad, pad_len)) {
                                DEBUG(0, ("api_pipe_bind_req: failed to add "
                                          "%u bytes of pad data.\n",
                                          (unsigned int)pad_len));
                                goto err_exit;
                        }
                }

                if (!data_blob_append(p->mem_ctx, &p->out_data.frag,
                                        auth_blob.data, auth_blob.length)) {
                        DEBUG(0, ("Append of auth info failed.\n"));
                        goto err_exit;
                }
        }

        /*
         * Setup the lengths for the initial reply.
         */

        p->out_data.data_sent_length = 0;
        p->out_data.current_pdu_sent = 0;

        TALLOC_FREE(auth_blob.data);
        return True;

  err_exit:

        data_blob_free(&p->out_data.frag);
        TALLOC_FREE(auth_blob.data);
        return setup_bind_nak(p, pkt);
}

/****************************************************************************
 Find the set of RPC functions associated with this context_id
****************************************************************************/

static PIPE_RPC_FNS* find_pipe_fns_by_context( PIPE_RPC_FNS *list, uint32 context_id )
{
        PIPE_RPC_FNS *fns = NULL;

        if ( !list ) {
                DEBUG(0,("find_pipe_fns_by_context: ERROR!  No context list for pipe!\n"));
                return NULL;
        }

        for (fns=list; fns; fns=fns->next ) {
                if ( fns->context_id == context_id )
                        return fns;
        }
        return NULL;
}

/****************************************************************************
 Memory cleanup.
****************************************************************************/

void free_pipe_rpc_context( PIPE_RPC_FNS *list )
{
        PIPE_RPC_FNS *tmp = list;
        PIPE_RPC_FNS *tmp2;

        while (tmp) {
                tmp2 = tmp->next;
                SAFE_FREE(tmp);
                tmp = tmp2;
        }

        return; 
}

static bool api_rpcTNP(struct pipes_struct *p, struct ncacn_packet *pkt,
                       const struct api_struct *api_rpc_cmds, int n_cmds);

/****************************************************************************
 Find the correct RPC function to call for this request.
 If the pipe is authenticated then become the correct UNIX user
 before doing the call.
****************************************************************************/

bool api_pipe_request(struct pipes_struct *p, struct ncacn_packet *pkt)
{
        bool ret = False;
        bool changed_user = False;
        PIPE_RPC_FNS *pipe_fns;

        if (p->pipe_bound &&
            ((p->auth.auth_type == DCERPC_AUTH_TYPE_NTLMSSP) ||
             ((p->auth.auth_type == DCERPC_AUTH_TYPE_SPNEGO) &&
              (p->auth.spnego_type ==  PIPE_AUTH_TYPE_SPNEGO_NTLMSSP)))) {
                if(!become_authenticated_pipe_user(p)) {
                        data_blob_free(&p->out_data.rdata);
                        return False;
                }
                changed_user = True;
        }

        DEBUG(5, ("Requested \\PIPE\\%s\n",
                  get_pipe_name_from_syntax(talloc_tos(), &p->syntax)));

        /* get the set of RPC functions for this context */

        pipe_fns = find_pipe_fns_by_context(p->contexts,
                                            pkt->u.request.context_id);

        if ( pipe_fns ) {
                TALLOC_CTX *frame = talloc_stackframe();
                ret = api_rpcTNP(p, pkt, pipe_fns->cmds, pipe_fns->n_cmds);
                TALLOC_FREE(frame);
        }
        else {
                DEBUG(0, ("No rpc function table associated with context "
                          "[%d] on pipe [%s]\n",
                          pkt->u.request.context_id,
                          get_pipe_name_from_syntax(talloc_tos(),
                                                    &p->syntax)));
        }

        if (changed_user) {
                unbecome_authenticated_pipe_user();
        }

        return ret;
}

/*******************************************************************
 Calls the underlying RPC function for a named pipe.
 ********************************************************************/

static bool api_rpcTNP(struct pipes_struct *p, struct ncacn_packet *pkt,
                       const struct api_struct *api_rpc_cmds, int n_cmds)
{
        int fn_num;
        uint32_t offset1;

        /* interpret the command */
        DEBUG(4,("api_rpcTNP: %s op 0x%x - ",
                 get_pipe_name_from_syntax(talloc_tos(), &p->syntax),
                 pkt->u.request.opnum));

        if (DEBUGLEVEL >= 50) {
                fstring name;
                slprintf(name, sizeof(name)-1, "in_%s",
                         get_pipe_name_from_syntax(talloc_tos(), &p->syntax));
                dump_pdu_region(name, pkt->u.request.opnum,
                                &p->in_data.data, 0,
                                p->in_data.data.length);
        }

        for (fn_num = 0; fn_num < n_cmds; fn_num++) {
                if (api_rpc_cmds[fn_num].opnum == pkt->u.request.opnum &&
                    api_rpc_cmds[fn_num].fn != NULL) {
                        DEBUG(3, ("api_rpcTNP: rpc command: %s\n",
                                  api_rpc_cmds[fn_num].name));
                        break;
                }
        }

        if (fn_num == n_cmds) {
                /*
                 * For an unknown RPC just return a fault PDU but
                 * return True to allow RPC's on the pipe to continue
                 * and not put the pipe into fault state. JRA.
                 */
                DEBUG(4, ("unknown\n"));
                setup_fault_pdu(p, NT_STATUS(DCERPC_FAULT_OP_RNG_ERROR));
                return True;
        }

        offset1 = p->out_data.rdata.length;

        DEBUG(6, ("api_rpc_cmds[%d].fn == %p\n", 
                fn_num, api_rpc_cmds[fn_num].fn));
        /* do the actual command */
        if(!api_rpc_cmds[fn_num].fn(p)) {
                DEBUG(0,("api_rpcTNP: %s: %s failed.\n",
                         get_pipe_name_from_syntax(talloc_tos(), &p->syntax),
                         api_rpc_cmds[fn_num].name));
                data_blob_free(&p->out_data.rdata);
                return False;
        }

        if (p->bad_handle_fault_state) {
                DEBUG(4,("api_rpcTNP: bad handle fault return.\n"));
                p->bad_handle_fault_state = False;
                setup_fault_pdu(p, NT_STATUS(DCERPC_FAULT_CONTEXT_MISMATCH));
                return True;
        }

        if (p->rng_fault_state) {
                DEBUG(4, ("api_rpcTNP: rng fault return\n"));
                p->rng_fault_state = False;
                setup_fault_pdu(p, NT_STATUS(DCERPC_FAULT_OP_RNG_ERROR));
                return True;
        }

        if (DEBUGLEVEL >= 50) {
                fstring name;
                slprintf(name, sizeof(name)-1, "out_%s",
                         get_pipe_name_from_syntax(talloc_tos(), &p->syntax));
                dump_pdu_region(name, pkt->u.request.opnum,
                                &p->out_data.rdata, offset1,
                                p->out_data.rdata.length);
        }

        DEBUG(5,("api_rpcTNP: called %s successfully\n",
                 get_pipe_name_from_syntax(talloc_tos(), &p->syntax)));

        /* Check for buffer underflow in rpc parsing */
        if ((DEBUGLEVEL >= 10) &&
            (pkt->frag_length < p->in_data.data.length)) {
                DEBUG(10, ("api_rpcTNP: rpc input buffer underflow (parse error?)\n"));
                dump_data(10, p->in_data.data.data + pkt->frag_length,
                              p->in_data.data.length - pkt->frag_length);
        }

        return True;
}

/****************************************************************************
 Initialise an outgoing packet.
****************************************************************************/

static bool pipe_init_outgoing_data(struct pipes_struct *p)
{
        output_data *o_data = &p->out_data;

        /* Reset the offset counters. */
        o_data->data_sent_length = 0;
        o_data->current_pdu_sent = 0;

        data_blob_free(&o_data->frag);

        /* Free any memory in the current return data buffer. */
        data_blob_free(&o_data->rdata);

        return True;
}

/****************************************************************************
 Sets the fault state on incoming packets.
****************************************************************************/

void set_incoming_fault(struct pipes_struct *p)
{
        data_blob_free(&p->in_data.data);
        p->in_data.pdu_needed_len = 0;
        p->in_data.pdu.length = 0;
        p->fault_state = True;
        DEBUG(10, ("set_incoming_fault: Setting fault state on pipe %s\n",
                   get_pipe_name_from_syntax(talloc_tos(), &p->syntax)));
}

static NTSTATUS dcesrv_auth_request(struct pipe_auth_data *auth,
                                    struct ncacn_packet *pkt,
                                    DATA_BLOB *raw_pkt)
{
        NTSTATUS status;
        size_t hdr_size = DCERPC_REQUEST_LENGTH;
        size_t pad_len;

        DEBUG(10, ("Checking request auth.\n"));

        if (pkt->pfc_flags & DCERPC_PFC_FLAG_OBJECT_UUID) {
                hdr_size += 16;
        }

        /* in case of sealing this function will unseal the data in place */
        status = dcerpc_check_auth(auth, pkt,
                                   &pkt->u.request.stub_and_verifier,
                                   hdr_size, raw_pkt,
                                   &pad_len);
        if (!NT_STATUS_IS_OK(status)) {
                return status;
        }


        /* remove padding and auth trailer,
         * this way the caller will get just the data */
        if (pkt->auth_length) {
                size_t trail_len = pad_len
                                        + DCERPC_AUTH_TRAILER_LENGTH
                                        + pkt->auth_length;
                if (pkt->u.request.stub_and_verifier.length < trail_len) {
                        return NT_STATUS_INFO_LENGTH_MISMATCH;
                }
                pkt->u.request.stub_and_verifier.length -= trail_len;
        }

        return NT_STATUS_OK;
}

/****************************************************************************
 Processes a request pdu. This will do auth processing if needed, and
 appends the data into the complete stream if the LAST flag is not set.
****************************************************************************/

static bool process_request_pdu(struct pipes_struct *p, struct ncacn_packet *pkt)
{
        NTSTATUS status;
        DATA_BLOB data;

        if (!p->pipe_bound) {
                DEBUG(0,("process_request_pdu: rpc request with no bind.\n"));
                set_incoming_fault(p);
                return False;
        }

        /* Store the opnum */
        p->opnum = pkt->u.request.opnum;

        status = dcesrv_auth_request(&p->auth, pkt, &p->in_data.pdu);
        if (!NT_STATUS_IS_OK(status)) {
                DEBUG(0, ("Failed to check packet auth. (%s)\n",
                          nt_errstr(status)));
                set_incoming_fault(p);
                return false;
        }

        data = pkt->u.request.stub_and_verifier;

        /*
         * Check the data length doesn't go over the 15Mb limit.
         * increased after observing a bug in the Windows NT 4.0 SP6a
         * spoolsv.exe when the response to a GETPRINTERDRIVER2 RPC
         * will not fit in the initial buffer of size 0x1068   --jerry 22/01/2002
         */

        if (p->in_data.data.length + data.length > MAX_RPC_DATA_SIZE) {
                DEBUG(0, ("process_request_pdu: "
                          "rpc data buffer too large (%u) + (%u)\n",
                          (unsigned int)p->in_data.data.length,
                          (unsigned int)data.length));
                set_incoming_fault(p);
                return False;
        }

        /*
         * Append the data portion into the buffer and return.
         */

        if (data.length) {
                if (!data_blob_append(p->mem_ctx, &p->in_data.data,
                                          data.data, data.length)) {
                        DEBUG(0, ("Unable to append data size %u "
                                  "to parse buffer of size %u.\n",
                                  (unsigned int)data.length,
                                  (unsigned int)p->in_data.data.length));
                        set_incoming_fault(p);
                        return False;
                }
        }

        if (pkt->pfc_flags & DCERPC_PFC_FLAG_LAST) {
                bool ret = False;
                /*
                 * Ok - we finally have a complete RPC stream.
                 * Call the rpc command to process it.
                 */

                /*
                 * Process the complete data stream here.
                 */
                if (pipe_init_outgoing_data(p)) {
                        ret = api_pipe_request(p, pkt);
                }

                return ret;
        }

        return True;
}

/****************************************************************************
 Processes a finished PDU stored in p->in_data.pdu.
****************************************************************************/

void process_complete_pdu(struct pipes_struct *p)
{
        struct ncacn_packet *pkt = NULL;
        NTSTATUS status;
        bool reply = False;

        if(p->fault_state) {
                DEBUG(10,("process_complete_pdu: pipe %s in fault state.\n",
                          get_pipe_name_from_syntax(talloc_tos(), &p->syntax)));
                goto done;
        }

        pkt = talloc(p->mem_ctx, struct ncacn_packet);
        if (!pkt) {
                DEBUG(0, ("Out of memory!\n"));
                goto done;
        }

        /*
         * Ensure we're using the corrent endianness for both the
         * RPC header flags and the raw data we will be reading from.
         */
        if (dcerpc_get_endian_flag(&p->in_data.pdu) & DCERPC_DREP_LE) {
                p->endian = RPC_LITTLE_ENDIAN;
        } else {
                p->endian = RPC_BIG_ENDIAN;
        }
        DEBUG(10, ("PDU is in %s Endian format!\n", p->endian?"Big":"Little"));

        status = dcerpc_pull_ncacn_packet(pkt, &p->in_data.pdu,
                                          pkt, p->endian);
        if (!NT_STATUS_IS_OK(status)) {
                DEBUG(0, ("Failed to unmarshal rpc packet: %s!\n",
                          nt_errstr(status)));
                goto done;
        }

        /* Store the call_id */
        p->call_id = pkt->call_id;

        DEBUG(10, ("Processing packet type %d\n", (int)pkt->ptype));

        switch (pkt->ptype) {
        case DCERPC_PKT_REQUEST:
                reply = process_request_pdu(p, pkt);
                break;

        case DCERPC_PKT_PING: /* CL request - ignore... */
                DEBUG(0, ("process_complete_pdu: Error. "
                          "Connectionless packet type %d received on "
                          "pipe %s.\n", (int)pkt->ptype,
                         get_pipe_name_from_syntax(talloc_tos(),
                                                   &p->syntax)));
                break;

        case DCERPC_PKT_RESPONSE: /* No responses here. */
                DEBUG(0, ("process_complete_pdu: Error. "
                          "DCERPC_PKT_RESPONSE received from client "
                          "on pipe %s.\n",
                         get_pipe_name_from_syntax(talloc_tos(),
                                                   &p->syntax)));
                break;

        case DCERPC_PKT_FAULT:
        case DCERPC_PKT_WORKING:
                /* CL request - reply to a ping when a call in process. */
        case DCERPC_PKT_NOCALL:
                /* CL - server reply to a ping call. */
        case DCERPC_PKT_REJECT:
        case DCERPC_PKT_ACK:
        case DCERPC_PKT_CL_CANCEL:
        case DCERPC_PKT_FACK:
        case DCERPC_PKT_CANCEL_ACK:
                DEBUG(0, ("process_complete_pdu: Error. "
                          "Connectionless packet type %u received on "
                          "pipe %s.\n", (unsigned int)pkt->ptype,
                         get_pipe_name_from_syntax(talloc_tos(),
                                                   &p->syntax)));
                break;

        case DCERPC_PKT_BIND:
                /*
                 * We assume that a pipe bind is only in one pdu.
                 */
                if (pipe_init_outgoing_data(p)) {
                        reply = api_pipe_bind_req(p, pkt);
                }
                break;

        case DCERPC_PKT_BIND_ACK:
        case DCERPC_PKT_BIND_NAK:
                DEBUG(0, ("process_complete_pdu: Error. "
                          "DCERPC_PKT_BINDACK/DCERPC_PKT_BINDNACK "
                          "packet type %u received on pipe %s.\n",
                          (unsigned int)pkt->ptype,
                         get_pipe_name_from_syntax(talloc_tos(),
                                                   &p->syntax)));
                break;


        case DCERPC_PKT_ALTER:
                /*
                 * We assume that a pipe bind is only in one pdu.
                 */
                if (pipe_init_outgoing_data(p)) {
                        reply = api_pipe_alter_context(p, pkt);
                }
                break;

        case DCERPC_PKT_ALTER_RESP:
                DEBUG(0, ("process_complete_pdu: Error. "
                          "DCERPC_PKT_ALTER_RESP on pipe %s: "
                          "Should only be server -> client.\n",
                         get_pipe_name_from_syntax(talloc_tos(),
                                                   &p->syntax)));
                break;

        case DCERPC_PKT_AUTH3:
                /*
                 * The third packet in an NTLMSSP auth exchange.
                 */
                if (pipe_init_outgoing_data(p)) {
                        reply = api_pipe_bind_auth3(p, pkt);
                }
                break;

        case DCERPC_PKT_SHUTDOWN:
                DEBUG(0, ("process_complete_pdu: Error. "
                          "DCERPC_PKT_SHUTDOWN on pipe %s: "
                          "Should only be server -> client.\n",
                         get_pipe_name_from_syntax(talloc_tos(),
                                                   &p->syntax)));
                break;

        case DCERPC_PKT_CO_CANCEL:
                /* For now just free all client data and continue
                 * processing. */
                DEBUG(3,("process_complete_pdu: DCERPC_PKT_CO_CANCEL."
                         " Abandoning rpc call.\n"));
                /* As we never do asynchronous RPC serving, we can
                 * never cancel a call (as far as I know).
                 * If we ever did we'd have to send a cancel_ack reply.
                 * For now, just free all client data and continue
                 * processing. */
                reply = True;
                break;

#if 0
                /* Enable this if we're doing async rpc. */
                /* We must check the outstanding callid matches. */
                if (pipe_init_outgoing_data(p)) {
                        /* Send a cancel_ack PDU reply. */
                        /* We should probably check the auth-verifier here. */
                        reply = setup_cancel_ack_reply(p, pkt);
                }
                break;
#endif

        case DCERPC_PKT_ORPHANED:
                /* We should probably check the auth-verifier here.
                 * For now just free all client data and continue
                 * processing. */
                DEBUG(3, ("process_complete_pdu: DCERPC_PKT_ORPHANED."
                          " Abandoning rpc call.\n"));
                reply = True;
                break;

        default:
                DEBUG(0, ("process_complete_pdu: "
                          "Unknown rpc type = %u received.\n",
                          (unsigned int)pkt->ptype));
                break;
        }

done:
        if (!reply) {
                DEBUG(3,("process_complete_pdu: DCE/RPC fault sent on "
                         "pipe %s\n", get_pipe_name_from_syntax(talloc_tos(),
                                                                &p->syntax)));
                set_incoming_fault(p);
                setup_fault_pdu(p, NT_STATUS(DCERPC_FAULT_OP_RNG_ERROR));
                TALLOC_FREE(pkt);
        } else {
                /*
                 * Reset the lengths. We're ready for a new pdu.
                 */
                TALLOC_FREE(p->in_data.pdu.data);
                p->in_data.pdu_needed_len = 0;
                p->in_data.pdu.length = 0;
        }

        TALLOC_FREE(pkt);
}