source3/libads/sasl.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    ads sasl code
   4    Copyright (C) Andrew Tridgell 2001
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19 */
  20
  21 #include "includes.h"
  22
  23 #ifdef HAVE_ADS
  24
  25 #if USE_CYRUS_SASL
  26 /*
  27   this is a minimal interact function, just enough for SASL to talk
  28   GSSAPI/kerberos to W2K
  29   Error handling is a bit of a problem. I can't see how to get Cyrus-sasl
  30   to give sensible errors
  31 */
  32 static int sasl_interact(LDAP *ld,unsigned flags,void *defaults,void *in)
  33 {
  34         sasl_interact_t *interact = in;
  35
  36         while (interact->id != SASL_CB_LIST_END) {
  37                 interact->result = strdup("");
  38                 interact->len = strlen(interact->result);
  39                 interact++;
  40         }
  41
  42         return LDAP_SUCCESS;
  43 }
  44 #endif
  45
  46
  47 #define MAX_GSS_PASSES 3
  48
  49 /* this performs a SASL/gssapi bind
  50    we avoid using cyrus-sasl to make Samba more robust. cyrus-sasl
  51    is very dependent on correctly configured DNS whereas
  52    this routine is much less fragile
  53    see RFC2078 for details
  54 */
  55 ADS_STATUS ads_sasl_gssapi_bind(ADS_STRUCT *ads)
  56 {
  57         int minor_status;
  58         gss_name_t serv_name;
  59         gss_buffer_desc input_name;
  60         gss_ctx_id_t context_handle;
  61         gss_OID mech_type = GSS_C_NULL_OID;
  62         gss_buffer_desc output_token, input_token;
  63         OM_uint32 ret_flags, conf_state;
  64         struct berval cred;
  65         struct berval *scred;
  66         int i=0;
  67         int gss_rc, rc;
  68         uint8 *p;
  69         uint32 max_msg_size;
  70         char *sname;
  71         ADS_STATUS status;
  72         krb5_principal principal;
  73         krb5_context ctx;
  74         krb5_enctype enc_types[] = {ENCTYPE_DES_CBC_MD5, ENCTYPE_NULL};
  75         gss_OID_desc nt_principal =
  76         {10, "\052\206\110\206\367\022\001\002\002\002"};
  77
  78         /* we need to fetch a service ticket as the ldap user in the
  79            servers realm, regardless of our realm */
  80         asprintf(&sname, "ldap/%s@%s", ads->ldap_server_name, ads->server_realm);
  81         krb5_init_context(&ctx);
  82         krb5_set_default_tgs_ktypes(ctx, enc_types);
  83         krb5_parse_name(ctx, sname, &principal);
  84         free(sname);
  85         krb5_free_context(ctx);
  86
  87         input_name.value = &principal;
  88         input_name.length = sizeof(principal);
  89
  90         gss_rc = gss_import_name(&minor_status,&input_name,&nt_principal, &serv_name);
  91         if (gss_rc) {
  92                 return ADS_ERROR_GSS(gss_rc, minor_status);
  93         }
  94
  95         context_handle = GSS_C_NO_CONTEXT;
  96
  97         input_token.value = NULL;
  98         input_token.length = 0;
  99
 100         for (i=0; i < MAX_GSS_PASSES; i++) {
 101                 gss_rc = gss_init_sec_context(&minor_status,
 102                                           GSS_C_NO_CREDENTIAL,
 103                                           &context_handle,
 104                                           serv_name,
 105                                           mech_type,
 106                                           GSS_C_MUTUAL_FLAG | GSS_C_REPLAY_FLAG,
 107                                           0,
 108                                           NULL,
 109                                           &input_token,
 110                                           NULL,
 111                                           &output_token,
 112                                           &ret_flags,
 113                                           NULL);
 114
 115                 if (input_token.value) {
 116                         gss_release_buffer(&minor_status, &input_token);
 117                 }
 118
 119                 if (gss_rc && gss_rc != GSS_S_CONTINUE_NEEDED) {
 120                         status = ADS_ERROR_GSS(gss_rc, minor_status);
 121                         goto failed;
 122                 }
 123
 124                 cred.bv_val = output_token.value;
 125                 cred.bv_len = output_token.length;
 126
 127                 rc = ldap_sasl_bind_s(ads->ld, NULL, "GSSAPI", &cred, NULL, NULL,
 128                                       &scred);
 129                 if (rc != LDAP_SASL_BIND_IN_PROGRESS) {
 130                         status = ADS_ERROR(rc);
 131                         goto failed;
 132                 }
 133
 134                 if (output_token.value) {
 135                         gss_release_buffer(&minor_status, &output_token);
 136                 }
 137
 138                 if (scred) {
 139                         input_token.value = scred->bv_val;
 140                         input_token.length = scred->bv_len;
 141                 } else {
 142                         input_token.value = NULL;
 143                         input_token.length = 0;
 144                 }
 145
 146                 if (gss_rc == 0) break;
 147         }
 148
 149         gss_release_name(&minor_status, &serv_name);
 150
 151         gss_rc = gss_unwrap(&minor_status,context_handle,&input_token,&output_token,
 152                             &conf_state,NULL);
 153         if (gss_rc) {
 154                 status = ADS_ERROR_GSS(gss_rc, minor_status);
 155                 goto failed;
 156         }
 157
 158         gss_release_buffer(&minor_status, &input_token);
 159
 160         p = (uint8 *)output_token.value;
 161
 162         max_msg_size = (p[1]<<16) | (p[2]<<8) | p[3];
 163
 164         gss_release_buffer(&minor_status, &output_token);
 165
 166         output_token.value = malloc(strlen(ads->bind_path) + 8);
 167         p = output_token.value;
 168
 169         *p++ = 1; /* no sign or seal */
 170         /* choose the same size as the server gave us */
 171         *p++ = max_msg_size>>16;
 172         *p++ = max_msg_size>>8;
 173         *p++ = max_msg_size;
 174         snprintf(p, strlen(ads->bind_path)+4, "dn:%s", ads->bind_path);
 175
 176         output_token.length = strlen(ads->bind_path) + 8;
 177
 178         gss_rc = gss_wrap(&minor_status, context_handle,0,GSS_C_QOP_DEFAULT,
 179                           &output_token, &conf_state,
 180                           &input_token);
 181         if (gss_rc) {
 182                 status = ADS_ERROR_GSS(gss_rc, minor_status);
 183                 goto failed;
 184         }
 185
 186         free(output_token.value);
 187
 188         cred.bv_val = input_token.value;
 189         cred.bv_len = input_token.length;
 190
 191         rc = ldap_sasl_bind_s(ads->ld, NULL, "GSSAPI", &cred, NULL, NULL,
 192                               &scred);
 193         status = ADS_ERROR(rc);
 194
 195         gss_release_buffer(&minor_status, &input_token);
 196
 197 failed:
 198         return status;
 199 }
 200
 201 ADS_STATUS ads_sasl_bind(ADS_STRUCT *ads)
 202 {
 203 #if USE_CYRUS_SASL
 204         int rc;
 205         rc = ldap_sasl_interactive_bind_s(ads->ld, NULL, NULL, NULL, NULL,
 206                                           LDAP_SASL_QUIET,
 207                                           sasl_interact, NULL);
 208         return ADS_ERROR(rc);
 209 #else
 210         return ads_sasl_gssapi_bind(ads);
 211 #endif
 212 }
 213
 214 #endif
 215