source: branches/samba-3.5.x/source4/librpc/rpc/dcerpc_auth.c

/* 
   Unix SMB/CIFS implementation.

   Generic Authentication Interface

   Copyright (C) Andrew Tridgell 2003
   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2004-2005
   Copyright (C) Stefan Metzmacher 2004
   
   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/>.
*/

#include "includes.h"
#include "libcli/composite/composite.h"
#include "auth/gensec/gensec.h"
#include "librpc/rpc/dcerpc.h"
#include "librpc/rpc/dcerpc_proto.h"
#include "param/param.h"

/*
  return the rpc syntax and transfer syntax given the pipe uuid and version
*/
static NTSTATUS dcerpc_init_syntaxes(const struct ndr_interface_table *table,
                                     uint32_t pipe_flags,
                                     struct ndr_syntax_id *syntax,
                                     struct ndr_syntax_id *transfer_syntax)
{
        syntax->uuid = table->syntax_id.uuid;
        syntax->if_version = table->syntax_id.if_version;

        if (pipe_flags & DCERPC_NDR64) {
                *transfer_syntax = ndr64_transfer_syntax;
        } else {
                *transfer_syntax = ndr_transfer_syntax;
        }

        return NT_STATUS_OK;
}


/*
  Send request to do a non-authenticated dcerpc bind
*/
struct composite_context *dcerpc_bind_auth_none_send(TALLOC_CTX *mem_ctx,
                                                     struct dcerpc_pipe *p,
                                                     const struct ndr_interface_table *table)
{
        struct ndr_syntax_id syntax;
        struct ndr_syntax_id transfer_syntax;

        struct composite_context *c;

        c = composite_create(mem_ctx, p->conn->event_ctx);
        if (c == NULL) return NULL;

        c->status = dcerpc_init_syntaxes(table, p->conn->flags,
                                         &syntax, &transfer_syntax);
        if (!NT_STATUS_IS_OK(c->status)) {
                DEBUG(2,("Invalid uuid string in "
                         "dcerpc_bind_auth_none_send\n"));
                composite_error(c, c->status);
                return c;
        }

        /* c was only allocated as a container for a possible error */
        talloc_free(c);

        return dcerpc_bind_send(p, mem_ctx, &syntax, &transfer_syntax);
}


/*
  Receive result of a non-authenticated dcerpc bind
*/
NTSTATUS dcerpc_bind_auth_none_recv(struct composite_context *ctx)
{
        return dcerpc_bind_recv(ctx);
}


/*
  Perform sync non-authenticated dcerpc bind
*/
_PUBLIC_ NTSTATUS dcerpc_bind_auth_none(struct dcerpc_pipe *p,
                               const struct ndr_interface_table *table)
{
        struct composite_context *ctx;

        ctx = dcerpc_bind_auth_none_send(p, p, table);
        return dcerpc_bind_auth_none_recv(ctx);
}


struct bind_auth_state {
        struct dcerpc_pipe *pipe;
        DATA_BLOB credentials;
        bool more_processing;   /* Is there anything more to do after the
                                 * first bind itself received? */
};

static void bind_auth_recv_alter(struct composite_context *creq);

static void bind_auth_next_step(struct composite_context *c)
{
        struct bind_auth_state *state;
        struct dcerpc_security *sec;
        struct composite_context *creq;
        bool more_processing = false;

        state = talloc_get_type(c->private_data, struct bind_auth_state);
        sec = &state->pipe->conn->security_state;

        /* The status value here, from GENSEC is vital to the security
         * of the system.  Even if the other end accepts, if GENSEC
         * claims 'MORE_PROCESSING_REQUIRED' then you must keep
         * feeding it blobs, or else the remote host/attacker might
         * avoid mutal authentication requirements.
         *
         * Likewise, you must not feed GENSEC too much (after the OK),
         * it doesn't like that either
         */

        c->status = gensec_update(sec->generic_state, state,
                                  sec->auth_info->credentials,
                                  &state->credentials);
        data_blob_free(&sec->auth_info->credentials);

        if (NT_STATUS_EQUAL(c->status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
                more_processing = true;
                c->status = NT_STATUS_OK;
        }

        if (!composite_is_ok(c)) return;

        if (state->pipe->conn->flags & DCERPC_HEADER_SIGNING) {
                gensec_want_feature(sec->generic_state, GENSEC_FEATURE_SIGN_PKT_HEADER);
        }

        if (state->credentials.length == 0) {
                composite_done(c);
                return;
        }

        sec->auth_info->credentials = state->credentials;

        if (!more_processing) {
                /* NO reply expected, so just send it */
                c->status = dcerpc_auth3(state->pipe, state);
                data_blob_free(&state->credentials);
                sec->auth_info->credentials = data_blob(NULL, 0);
                if (!composite_is_ok(c)) return;

                composite_done(c);
                return;
        }

        /* We are demanding a reply, so use a request that will get us one */

        creq = dcerpc_alter_context_send(state->pipe, state,
                                         &state->pipe->syntax,
                                         &state->pipe->transfer_syntax);
        data_blob_free(&state->credentials);
        sec->auth_info->credentials = data_blob(NULL, 0);
        if (composite_nomem(creq, c)) return;

        composite_continue(c, creq, bind_auth_recv_alter, c);
}


static void bind_auth_recv_alter(struct composite_context *creq)
{
        struct composite_context *c = talloc_get_type(creq->async.private_data,
                                                      struct composite_context);

        c->status = dcerpc_alter_context_recv(creq);
        if (!composite_is_ok(c)) return;

        bind_auth_next_step(c);
}


static void bind_auth_recv_bindreply(struct composite_context *creq)
{
        struct composite_context *c = talloc_get_type(creq->async.private_data,
                                                      struct composite_context);
        struct bind_auth_state *state = talloc_get_type(c->private_data,
                                                        struct bind_auth_state);

        c->status = dcerpc_bind_recv(creq);
        if (!composite_is_ok(c)) return;

        if (!state->more_processing) {
                /* The first gensec_update has not requested a second run, so
                 * we're done here. */
                composite_done(c);
                return;
        }

        bind_auth_next_step(c);
}


/**
   Bind to a DCE/RPC pipe, send async request
   @param mem_ctx TALLOC_CTX for the allocation of the composite_context
   @param p The dcerpc_pipe to bind (must already be connected)
   @param table The interface table to use (the DCE/RPC bind both selects and interface and authenticates)
   @param credentials The credentials of the account to connect with 
   @param auth_type Select the authentication scheme to use
   @param auth_level Chooses between unprotected (connect), signed or sealed
   @param service The service (used by Kerberos to select the service principal to contact)
   @retval A composite context describing the partial state of the bind
*/

struct composite_context *dcerpc_bind_auth_send(TALLOC_CTX *mem_ctx,
                                                struct dcerpc_pipe *p,
                                                const struct ndr_interface_table *table,
                                                struct cli_credentials *credentials,
                                                struct gensec_settings *gensec_settings,
                                                uint8_t auth_type, uint8_t auth_level,
                                                const char *service)
{
        struct composite_context *c, *creq;
        struct bind_auth_state *state;
        struct dcerpc_security *sec;

        struct ndr_syntax_id syntax, transfer_syntax;

        /* composite context allocation and setup */
        c = composite_create(mem_ctx, p->conn->event_ctx);
        if (c == NULL) return NULL;

        state = talloc(c, struct bind_auth_state);
        if (composite_nomem(state, c)) return c;
        c->private_data = state;

        state->pipe = p;

        c->status = dcerpc_init_syntaxes(table, p->conn->flags,
                                         &syntax,
                                         &transfer_syntax);
        if (!composite_is_ok(c)) return c;

        sec = &p->conn->security_state;

        c->status = gensec_client_start(p, &sec->generic_state,
                                        p->conn->event_ctx,
                                        gensec_settings);
        if (!NT_STATUS_IS_OK(c->status)) {
                DEBUG(1, ("Failed to start GENSEC client mode: %s\n",
                          nt_errstr(c->status)));
                composite_error(c, c->status);
                return c;
        }

        c->status = gensec_set_credentials(sec->generic_state, credentials);
        if (!NT_STATUS_IS_OK(c->status)) {
                DEBUG(1, ("Failed to set GENSEC client credentials: %s\n",
                          nt_errstr(c->status)));
                composite_error(c, c->status);
                return c;
        }

        c->status = gensec_set_target_hostname(sec->generic_state,
                                               p->conn->transport.target_hostname(p->conn));
        if (!NT_STATUS_IS_OK(c->status)) {
                DEBUG(1, ("Failed to set GENSEC target hostname: %s\n", 
                          nt_errstr(c->status)));
                composite_error(c, c->status);
                return c;
        }

        if (service != NULL) {
                c->status = gensec_set_target_service(sec->generic_state,
                                                      service);
                if (!NT_STATUS_IS_OK(c->status)) {
                        DEBUG(1, ("Failed to set GENSEC target service: %s\n",
                                  nt_errstr(c->status)));
                        composite_error(c, c->status);
                        return c;
                }
        }

        c->status = gensec_start_mech_by_authtype(sec->generic_state,
                                                  auth_type, auth_level);
        if (!NT_STATUS_IS_OK(c->status)) {
                DEBUG(1, ("Failed to start GENSEC client mechanism %s: %s\n",
                          gensec_get_name_by_authtype(sec->generic_state, auth_type),
                          nt_errstr(c->status)));
                composite_error(c, c->status);
                return c;
        }

        sec->auth_info = talloc(p, struct dcerpc_auth);
        if (composite_nomem(sec->auth_info, c)) return c;

        sec->auth_info->auth_type = auth_type;
        sec->auth_info->auth_level = auth_level,
        sec->auth_info->auth_pad_length = 0;
        sec->auth_info->auth_reserved = 0;
        sec->auth_info->auth_context_id = random();
        sec->auth_info->credentials = data_blob(NULL, 0);

        /* The status value here, from GENSEC is vital to the security
         * of the system.  Even if the other end accepts, if GENSEC
         * claims 'MORE_PROCESSING_REQUIRED' then you must keep
         * feeding it blobs, or else the remote host/attacker might
         * avoid mutal authentication requirements.
         *
         * Likewise, you must not feed GENSEC too much (after the OK),
         * it doesn't like that either
         */

        c->status = gensec_update(sec->generic_state, state,
                                  sec->auth_info->credentials,
                                  &state->credentials);
        if (!NT_STATUS_IS_OK(c->status) &&
            !NT_STATUS_EQUAL(c->status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
                composite_error(c, c->status);
                return c;
        }

        state->more_processing = NT_STATUS_EQUAL(c->status,
                                                 NT_STATUS_MORE_PROCESSING_REQUIRED);

        if (state->credentials.length == 0) {
                composite_done(c);
                return c;
        }

        sec->auth_info->credentials = state->credentials;

        /* The first request always is a dcerpc_bind. The subsequent ones
         * depend on gensec results */
        creq = dcerpc_bind_send(p, state, &syntax, &transfer_syntax);
        data_blob_free(&state->credentials);
        sec->auth_info->credentials = data_blob(NULL, 0);
        if (composite_nomem(creq, c)) return c;

        composite_continue(c, creq, bind_auth_recv_bindreply, c);
        return c;
}


/**
   Bind to a DCE/RPC pipe, receive result
   @param creq A composite context describing state of async call
   @retval NTSTATUS code
*/

NTSTATUS dcerpc_bind_auth_recv(struct composite_context *creq)
{
        NTSTATUS result = composite_wait(creq);
        struct bind_auth_state *state = talloc_get_type(creq->private_data,
                                                        struct bind_auth_state);

        if (NT_STATUS_IS_OK(result)) {
                /*
                  after a successful authenticated bind the session
                  key reverts to the generic session key
                */
                state->pipe->conn->security_state.session_key = dcerpc_generic_session_key;
        }
        
        talloc_free(creq);
        return result;
}


/**
   Perform a GENSEC authenticated bind to a DCE/RPC pipe, sync
   @param p The dcerpc_pipe to bind (must already be connected)
   @param table The interface table to use (the DCE/RPC bind both selects and interface and authenticates)
   @param credentials The credentials of the account to connect with 
   @param auth_type Select the authentication scheme to use
   @param auth_level Chooses between unprotected (connect), signed or sealed
   @param service The service (used by Kerberos to select the service principal to contact)
   @retval NTSTATUS status code
*/

_PUBLIC_ NTSTATUS dcerpc_bind_auth(struct dcerpc_pipe *p,
                          const struct ndr_interface_table *table,
                          struct cli_credentials *credentials,
                          struct gensec_settings *gensec_settings,
                          uint8_t auth_type, uint8_t auth_level,
                          const char *service)
{
        struct composite_context *creq;
        creq = dcerpc_bind_auth_send(p, p, table, credentials, gensec_settings,
                                     auth_type, auth_level, service);
        return dcerpc_bind_auth_recv(creq);
}