src/sip-sec-krb5.c

   1 /**
   2  * @file sip-sec-krb5.c
   3  *
   4  * pidgin-sipe
   5  *
   6  * Copyright (C) 2009 pier11 <pier11@operamail.com>
   7  *
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  22  */
  23
  24 #include <glib.h>
  25 #include <stdio.h>
  26 #include <string.h>
  27 #include <gssapi.h>
  28 #include <gssapi/gssapi_krb5.h>
  29
  30 #include "sip-sec.h"
  31 #include "sip-sec-mech.h"
  32 #include "sip-sec-krb5.h"
  33
  34 /* Security context for Kerberos */
  35 typedef struct _context_krb5 {
  36         struct sip_sec_context common;
  37         gss_cred_id_t cred_krb5;
  38         gss_ctx_id_t ctx_krb5;
  39 } *context_krb5;
  40
  41 void sip_sec_krb5_print_gss_error(char *func, OM_uint32 ret, OM_uint32 minor);
  42
  43 void
  44 sip_sec_krb5_obtain_tgt(const char *realm,
  45                         const char *username,
  46                         const char *password);
  47
  48 /* sip-sec-mech.h API implementation for Kerberos/GSS-API */
  49
  50 /**
  51  * Depending on Single Sign-On flag (sso),
  52  * obtains existing credentials stored in credentials cash in case of Kerberos,
  53  * or attemps to obtain TGT on its own first.
  54  */
  55 static sip_uint32
  56 sip_sec_acquire_cred__krb5(SipSecContext context,
  57                             const char *domain,
  58                             const char *username,
  59                             const char *password)
  60 {
  61         OM_uint32 ret;
  62         OM_uint32 minor;
  63         OM_uint32 expiry;
  64         struct gss_cred_id_struct* credentials;
  65
  66         if (!context->sso) {
  67                 /* Do not use default credentials, obtain a new one and store it in cache */
  68                 sip_sec_krb5_obtain_tgt(g_ascii_strup(domain, -1), username, password);
  69         }
  70
  71         /* Acquire default user credentials */
  72         ret = gss_acquire_cred(&minor,
  73                                GSS_C_NO_NAME,
  74                                GSS_C_INDEFINITE,
  75                                GSS_C_NO_OID_SET,
  76                                GSS_C_INITIATE,
  77                                &credentials,
  78                                NULL,
  79                                &expiry);
  80
  81         if (GSS_ERROR(ret)) {
  82                 sip_sec_krb5_print_gss_error("gss_acquire_cred", ret, minor);
  83                 printf("ERROR: sip_sec_acquire_cred0__krb5: failed to acquire credentials. ret=%d\n", (int)ret);
  84                 return SIP_SEC_E_INTERNAL_ERROR;
  85         } else {
  86                 ((context_krb5)context)->cred_krb5 = credentials;
  87                 return SIP_SEC_E_OK;
  88         }
  89 }
  90
  91 static sip_uint32
  92 sip_sec_init_sec_context__krb5(SipSecContext context,
  93                                SipSecBuffer in_buff,
  94                                SipSecBuffer *out_buff,
  95                                const char *service_name)
  96 {
  97         OM_uint32 ret;
  98         OM_uint32 minor;
  99         OM_uint32 expiry;
 100         OM_uint32 request_flags;
 101         OM_uint32 response_flags;
 102         gss_buffer_desc input_token;
 103         gss_buffer_desc output_token;
 104         gss_buffer_desc input_name_buffer;
 105         gss_name_t target_name;
 106         context_krb5 ctx = (context_krb5) context;
 107
 108         input_name_buffer.value = (void *)service_name;
 109         input_name_buffer.length = strlen(input_name_buffer.value) + 1;
 110
 111         ret = gss_import_name(&minor,
 112                               &input_name_buffer,
 113                               (const gss_OID)GSS_KRB5_NT_PRINCIPAL_NAME,
 114                               &target_name);
 115         if (GSS_ERROR(ret)) {
 116                 sip_sec_krb5_print_gss_error("gss_import_name", ret, minor);
 117                 printf("ERROR: sip_sec_init_sec_context__krb5: failed to construct target name. Returned. ret=%d\n", (int)ret);
 118                 return SIP_SEC_E_INTERNAL_ERROR;
 119         }
 120
 121         request_flags = GSS_C_INTEG_FLAG;
 122
 123         input_token.length = in_buff.length;
 124         input_token.value = in_buff.value;
 125
 126         output_token.length = 0;
 127         output_token.value = NULL;
 128
 129         ret = gss_init_sec_context(&minor,
 130                                    ctx->cred_krb5,
 131                                    &(ctx->ctx_krb5),
 132                                    target_name,
 133                                    GSS_C_NO_OID,
 134                                    request_flags,
 135                                    GSS_C_INDEFINITE,
 136                                    GSS_C_NO_CHANNEL_BINDINGS,
 137                                    &input_token,
 138                                    NULL,
 139                                    &output_token,
 140                                    &response_flags,
 141                                    &expiry);
 142
 143         if (GSS_ERROR(ret)) {
 144                 sip_sec_krb5_print_gss_error("gss_init_sec_context", ret, minor);
 145                 printf("ERROR: sip_sec_init_sec_context__krb5: failed to initialize context. ret=%d\n", (int)ret);
 146                 return SIP_SEC_E_INTERNAL_ERROR;
 147         } else {
 148                 ret = gss_release_cred(&minor, &(ctx->cred_krb5));
 149                 if (GSS_ERROR(ret)) {
 150                         sip_sec_krb5_print_gss_error("gss_release_cred", ret, minor);
 151                         printf("ERROR: sip_sec_init_sec_context__krb5: failed to release credentials. ret=%d\n", (int)ret);
 152                 }
 153
 154                 input_token.value = NULL;
 155                 input_token.length = 0;
 156
 157                 out_buff->length = output_token.length;
 158                 out_buff->value = output_token.value;
 159
 160                 context->expires = (int)expiry;
 161                 return SIP_SEC_E_OK;
 162         }
 163 }
 164
 165 /**
 166  * @param message a NULL terminated string to sign
 167  */
 168 static sip_uint32
 169 sip_sec_make_signature__krb5(SipSecContext context,
 170                              const char *message,
 171                              SipSecBuffer *signature)
 172 {
 173         OM_uint32 ret;
 174         OM_uint32 minor;
 175         gss_buffer_desc input_message;
 176         gss_buffer_desc output_token;
 177
 178         input_message.value = (void *)message;
 179         input_message.length = strlen(input_message.value);
 180
 181         ret = gss_get_mic(&minor,
 182                           ((context_krb5)context)->ctx_krb5,
 183                           GSS_C_QOP_DEFAULT,
 184                           &input_message,
 185                           &output_token);
 186
 187         if (GSS_ERROR(ret)) {
 188                 sip_sec_krb5_print_gss_error("gss_get_mic", ret, minor);
 189                 printf("ERROR: sip_ssp_make_signature: failed to make signature. ret=%d\n", (int)ret);
 190                 return SIP_SEC_E_INTERNAL_ERROR;
 191         } else {
 192                 signature->value = output_token.value;
 193                 signature->length = output_token.length;
 194
 195                 return SIP_SEC_E_OK;
 196         }
 197 }
 198
 199 /**
 200  * @param message a NULL terminated string to check signature of
 201  */
 202 static sip_uint32
 203 sip_sec_verify_signature__krb5(SipSecContext context,
 204                                const char *message,
 205                                SipSecBuffer signature)
 206 {
 207         OM_uint32 ret;
 208         OM_uint32 minor;
 209         gss_qop_t qop_state;
 210         gss_buffer_desc input_message;
 211         gss_buffer_desc input_token;
 212
 213         input_message.value = (void *)message;
 214         input_message.length = strlen(input_message.value);
 215
 216         input_token.value = signature.value;
 217         input_token.length = signature.length;
 218
 219         ret = gss_verify_mic(&minor,
 220                              ((context_krb5)context)->ctx_krb5,
 221                              &input_message,
 222                              &input_token,
 223                              &qop_state);
 224
 225         if (GSS_ERROR(ret)) {
 226                 sip_sec_krb5_print_gss_error("gss_verify_mic", ret, minor);
 227                 printf("ERROR: sip_sec_verify_signature__krb5: failed to make signature. ret=%d\n", (int)ret);
 228                 return SIP_SEC_E_INTERNAL_ERROR;
 229         } else {
 230                 return SIP_SEC_E_OK;
 231         }
 232 }
 233
 234 static void
 235 sip_sec_destroy_sec_context__krb5(SipSecContext context)
 236 {
 237         OM_uint32 ret;
 238         OM_uint32 minor;
 239         context_krb5 ctx = (context_krb5) context;
 240
 241         if (ctx->cred_krb5) {
 242                 ret = gss_release_cred(&minor, &(ctx->cred_krb5));
 243                 if (GSS_ERROR(ret)) {
 244                         sip_sec_krb5_print_gss_error("gss_release_cred", ret, minor);
 245                         printf("ERROR: sip_sec_destroy_sec_context__krb5: failed to release credentials. ret=%d\n", (int)ret);
 246                 }
 247         }
 248
 249         if (ctx->ctx_krb5) {
 250                 ret = gss_delete_sec_context(&minor, &(ctx->ctx_krb5), GSS_C_NO_BUFFER);
 251                 if (GSS_ERROR(ret)) {
 252                         sip_sec_krb5_print_gss_error("gss_delete_sec_context", ret, minor);
 253                         printf("ERROR: sip_sec_destroy_sec_context__krb5: failed to delete security context. ret=%d\n", (int)ret);
 254                 }
 255         }
 256
 257         g_free(ctx);
 258 }
 259
 260 SipSecContext
 261 sip_sec_create_context__krb5(SIPE_UNUSED_PARAMETER SipSecAuthType type)
 262 {
 263         context_krb5 context = g_malloc0(sizeof(struct _context_krb5));
 264         if (!context) return(NULL);
 265
 266         context->common.acquire_cred_func     = sip_sec_acquire_cred__krb5;
 267         context->common.init_context_func     = sip_sec_init_sec_context__krb5;
 268         context->common.destroy_context_func  = sip_sec_destroy_sec_context__krb5;
 269         context->common.make_signature_func   = sip_sec_make_signature__krb5;
 270         context->common.verify_signature_func = sip_sec_verify_signature__krb5;
 271
 272         return((SipSecContext) context);
 273 }
 274
 275
 276 static void
 277 sip_sec_krb5_print_gss_error0(char *func,
 278                              OM_uint32 status,
 279                              int type)
 280 {
 281         OM_uint32 ret;
 282         OM_uint32 minor;
 283         OM_uint32 message_context = 0;
 284         gss_buffer_desc status_string;
 285
 286         do {
 287                 ret = gss_display_status(&minor,
 288                                          status,
 289                                          type,
 290                                          GSS_C_NO_OID,
 291                                          &message_context,
 292                                          &status_string);
 293
 294                 printf("GSS-API error in %s (%s): %s\n", func, (type == GSS_C_GSS_CODE ? "GSS" : "Mech"), (char *)status_string.value);
 295                 gss_release_buffer(&minor, &status_string);
 296         } while (message_context != 0);
 297 }
 298
 299 /**
 300  * Prints out errors of GSS-API function invocation
 301  */
 302 void sip_sec_krb5_print_gss_error(char *func, OM_uint32 ret, OM_uint32 minor)
 303 {
 304         sip_sec_krb5_print_gss_error0(func, ret, GSS_C_GSS_CODE);
 305         sip_sec_krb5_print_gss_error0(func, minor, GSS_C_MECH_CODE);
 306 }
 307
 308 /**
 309  * Prints out errors of Kerberos 5 function invocation
 310  */
 311 void
 312 sip_sec_krb5_print_error(const char *func,
 313                          krb5_context context,
 314                          krb5_error_code ret);
 315
 316 /**
 317  * Obtains Kerberos TGT and stores it in default credentials cache.
 318  * Similar what kinit util would do.
 319  * Can be checked with klist util.
 320  *
 321  * kinit would require the following name:
 322  * alice@ATLANTA.LOCAL
 323  * where 'alice' is a username and
 324  * 'ATLANTA.LOCAL' is a realm (domain) .
 325  */
 326 void
 327 sip_sec_krb5_obtain_tgt(SIPE_UNUSED_PARAMETER const char *realm_in,
 328                         const char *username_in,
 329                         const char *password)
 330 {
 331         krb5_context    context;
 332         krb5_principal  principal;
 333         krb5_creds      credentials;
 334         krb5_ccache     ccdef;
 335         krb5_error_code ret;
 336         char *realm;
 337         char *username;
 338         gchar **domain_user;
 339         gchar **user_realm;
 340
 341         printf("sip_sec_krb5_obtain_tgt started\n");
 342
 343         memset(&credentials, 0, sizeof(krb5_creds));
 344
 345         /* extracts realm as domain part of username
 346          * either before '\' or after '@'
 347          */
 348         domain_user = g_strsplit(username_in, "\\", 2);
 349         if (domain_user && domain_user[1]) {
 350                 realm = g_ascii_strup(domain_user[0], -1);
 351                 username = g_strdup(domain_user[1]);
 352         } else {
 353                 realm = g_strdup("");
 354                 username = g_strdup(username_in);
 355         }
 356         g_strfreev(domain_user);
 357
 358         user_realm = g_strsplit(username, "@", 2);
 359         if (user_realm && user_realm[1]) {
 360                 g_free(username);
 361                 g_free(realm);
 362                 username = g_strdup(user_realm[0]);
 363                 realm = g_ascii_strup(user_realm[1], -1);
 364         }
 365         g_strfreev(user_realm);
 366
 367         /* Obtait TGT */
 368         if ((ret = krb5_init_context(&context))) {
 369                 sip_sec_krb5_print_error("krb5_init_context", context, ret);
 370         }
 371
 372         if (!ret && (ret = krb5_build_principal(context, &principal, strlen(realm), realm, username, NULL))) {
 373                 sip_sec_krb5_print_error("krb5_build_principal", context, ret);
 374         }
 375         g_free(username);
 376         g_free(realm);
 377
 378         if (!ret && (ret = krb5_get_init_creds_password(context, &credentials, principal, (char *)password, NULL, NULL, 0, NULL, NULL))) {
 379                 sip_sec_krb5_print_error("krb5_get_init_creds_password", context, ret);
 380         }
 381
 382         if (!ret) {
 383                 printf("sip_sec_krb5_obtain_tgt: new TGT obtained.\n");
 384         }
 385
 386
 387         /* Store TGT in default credential cache */
 388         if (!ret && (ret = krb5_cc_default(context, &ccdef))) {
 389                 sip_sec_krb5_print_error("krb5_cc_default", context, ret);
 390         }
 391
 392         if (!ret && (ret = krb5_cc_initialize(context, ccdef, credentials.client))) {
 393                 sip_sec_krb5_print_error("krb5_cc_initialize", context, ret);
 394         }
 395
 396         if (!ret && (ret = krb5_cc_store_cred(context, ccdef, &credentials))) {
 397                 sip_sec_krb5_print_error("krb5_cc_store_cred", context, ret);
 398         }
 399
 400         if (!ret) {
 401                 printf("sip_sec_krb5_obtain_tgt: new TGT stored in default credentials cache.\n");
 402         }
 403
 404
 405         if (principal)
 406                 krb5_free_principal(context, principal);
 407
 408         if (context)
 409                 krb5_free_context(context);
 410 }
 411
 412 void
 413 sip_sec_krb5_print_error(const char *func,
 414                          krb5_context context,
 415                          krb5_error_code ret)
 416 {
 417         const char *error_message = krb5_get_error_message(context, ret);
 418         printf("Kerberos 5 ERROR in %s: %s\n", func, error_message);
 419
 420         krb5_free_error_message(context, error_message);
 421 }
 422
 423 /*
 424   Local Variables:
 425   mode: c
 426   c-file-style: "bsd"
 427   indent-tabs-mode: t
 428   tab-width: 8
 429   End:
 430 */