source4/lib/tls/tls.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    transport layer security handling code
   5
   6    Copyright (C) Andrew Tridgell 2004-2005
   7    Copyright (C) Stefan Metzmacher 2004
   8    Copyright (C) Andrew Bartlett 2006
   9
  10    This program is free software; you can redistribute it and/or modify
  11    it under the terms of the GNU General Public License as published by
  12    the Free Software Foundation; either version 2 of the License, or
  13    (at your option) any later version.
  14
  15    This program is distributed in the hope that it will be useful,
  16    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18    GNU General Public License for more details.
  19
  20    You should have received a copy of the GNU General Public License
  21    along with this program; if not, write to the Free Software
  22    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  23 */
  24
  25 #include "includes.h"
  26 #include "lib/events/events.h"
  27 #include "lib/socket/socket.h"
  28
  29 #if HAVE_LIBGNUTLS
  30 #include "gnutls/gnutls.h"
  31
  32 #define DH_BITS 1024
  33
  34 /* hold persistent tls data */
  35 struct tls_params {
  36         gnutls_certificate_credentials x509_cred;
  37         gnutls_dh_params dh_params;
  38         BOOL tls_enabled;
  39 };
  40 #endif
  41
  42 /* hold per connection tls data */
  43 struct tls_context {
  44         struct socket_context *socket;
  45         struct fd_event *fde;
  46         BOOL tls_enabled;
  47 #if HAVE_LIBGNUTLS
  48         gnutls_session session;
  49         BOOL done_handshake;
  50         BOOL have_first_byte;
  51         uint8_t first_byte;
  52         BOOL tls_detect;
  53         const char *plain_chars;
  54         BOOL output_pending;
  55         gnutls_certificate_credentials xcred;
  56         BOOL interrupted;
  57 #endif
  58 };
  59
  60 BOOL tls_enabled(struct socket_context *sock)
  61 {
  62         struct tls_context *tls;
  63         if (!sock) {
  64                 return False;
  65         }
  66         if (strcmp(sock->backend_name, "tls") != 0) {
  67                 return False;
  68         }
  69         tls = talloc_get_type(sock->private_data, struct tls_context);
  70         if (!tls) {
  71                 return False;
  72         }
  73         return tls->tls_enabled;
  74 }
  75
  76
  77 #if HAVE_LIBGNUTLS
  78
  79 static const struct socket_ops tls_socket_ops;
  80
  81 static NTSTATUS tls_socket_init(struct socket_context *sock)
  82 {
  83         switch (sock->type) {
  84         case SOCKET_TYPE_STREAM:
  85                 break;
  86         default:
  87                 return NT_STATUS_INVALID_PARAMETER;
  88         }
  89
  90         sock->backend_name = "tls";
  91
  92         return NT_STATUS_OK;
  93 }
  94
  95 #define TLSCHECK(call) do { \
  96         ret = call; \
  97         if (ret < 0) { \
  98                 DEBUG(0,("TLS %s - %s\n", #call, gnutls_strerror(ret))); \
  99                 goto failed; \
 100         } \
 101 } while (0)
 102
 103
 104 /*
 105   callback for reading from a socket
 106 */
 107 static ssize_t tls_pull(gnutls_transport_ptr ptr, void *buf, size_t size)
 108 {
 109         struct tls_context *tls = talloc_get_type(ptr, struct tls_context);
 110         NTSTATUS status;
 111         size_t nread;
 112
 113         if (tls->have_first_byte) {
 114                 *(uint8_t *)buf = tls->first_byte;
 115                 tls->have_first_byte = False;
 116                 return 1;
 117         }
 118
 119         status = socket_recv(tls->socket, buf, size, &nread);
 120         if (NT_STATUS_EQUAL(status, NT_STATUS_END_OF_FILE)) {
 121                 return 0;
 122         }
 123         if (NT_STATUS_IS_ERR(status)) {
 124                 EVENT_FD_NOT_READABLE(tls->fde);
 125                 EVENT_FD_NOT_WRITEABLE(tls->fde);
 126                 errno = EBADF;
 127                 return -1;
 128         }
 129         if (!NT_STATUS_IS_OK(status)) {
 130                 EVENT_FD_READABLE(tls->fde);
 131                 errno = EAGAIN;
 132                 return -1;
 133         }
 134         if (tls->output_pending) {
 135                 EVENT_FD_WRITEABLE(tls->fde);
 136         }
 137         if (size != nread) {
 138                 EVENT_FD_READABLE(tls->fde);
 139         }
 140         return nread;
 141 }
 142
 143 /*
 144   callback for writing to a socket
 145 */
 146 static ssize_t tls_push(gnutls_transport_ptr ptr, const void *buf, size_t size)
 147 {
 148         struct tls_context *tls = talloc_get_type(ptr, struct tls_context);
 149         NTSTATUS status;
 150         size_t nwritten;
 151         DATA_BLOB b;
 152
 153         if (!tls->tls_enabled) {
 154                 return size;
 155         }
 156
 157         b.data = discard_const(buf);
 158         b.length = size;
 159
 160         status = socket_send(tls->socket, &b, &nwritten);
 161         if (NT_STATUS_EQUAL(status, STATUS_MORE_ENTRIES)) {
 162                 errno = EAGAIN;
 163                 return -1;
 164         }
 165         if (!NT_STATUS_IS_OK(status)) {
 166                 EVENT_FD_WRITEABLE(tls->fde);
 167                 return -1;
 168         }
 169         if (size != nwritten) {
 170                 EVENT_FD_WRITEABLE(tls->fde);
 171         }
 172         return nwritten;
 173 }
 174
 175 /*
 176   destroy a tls session
 177  */
 178 static int tls_destructor(void *ptr)
 179 {
 180         struct tls_context *tls = talloc_get_type(ptr, struct tls_context);
 181         int ret;
 182         ret = gnutls_bye(tls->session, GNUTLS_SHUT_WR);
 183         if (ret < 0) {
 184                 DEBUG(0,("TLS gnutls_bye failed - %s\n", gnutls_strerror(ret)));
 185         }
 186         return 0;
 187 }
 188
 189
 190 /*
 191   possibly continue the handshake process
 192 */
 193 static NTSTATUS tls_handshake(struct tls_context *tls)
 194 {
 195         int ret;
 196
 197         if (tls->done_handshake) {
 198                 return NT_STATUS_OK;
 199         }
 200
 201         ret = gnutls_handshake(tls->session);
 202         if (ret == GNUTLS_E_INTERRUPTED || ret == GNUTLS_E_AGAIN) {
 203                 if (gnutls_record_get_direction(tls->session) == 1) {
 204                         EVENT_FD_WRITEABLE(tls->fde);
 205                 }
 206                 return STATUS_MORE_ENTRIES;
 207         }
 208         if (ret < 0) {
 209                 DEBUG(0,("TLS gnutls_handshake failed - %s\n", gnutls_strerror(ret)));
 210                 return NT_STATUS_UNEXPECTED_NETWORK_ERROR;
 211         }
 212         tls->done_handshake = True;
 213         return NT_STATUS_OK;
 214 }
 215
 216 /*
 217   possibly continue an interrupted operation
 218 */
 219 static NTSTATUS tls_interrupted(struct tls_context *tls)
 220 {
 221         int ret;
 222
 223         if (!tls->interrupted) {
 224                 return NT_STATUS_OK;
 225         }
 226         if (gnutls_record_get_direction(tls->session) == 1) {
 227                 ret = gnutls_record_send(tls->session, NULL, 0);
 228         } else {
 229                 ret = gnutls_record_recv(tls->session, NULL, 0);
 230         }
 231         if (ret == GNUTLS_E_INTERRUPTED || ret == GNUTLS_E_AGAIN) {
 232                 return STATUS_MORE_ENTRIES;
 233         }
 234         tls->interrupted = False;
 235         return NT_STATUS_OK;
 236 }
 237
 238 /*
 239   see how many bytes are pending on the connection
 240 */
 241 static NTSTATUS tls_socket_pending(struct socket_context *sock, size_t *npending)
 242 {
 243         struct tls_context *tls = talloc_get_type(sock->private_data, struct tls_context);
 244         if (!tls->tls_enabled || tls->tls_detect) {
 245                 return socket_pending(tls->socket, npending);
 246         }
 247         *npending = gnutls_record_check_pending(tls->session);
 248         if (*npending == 0) {
 249                 NTSTATUS status = socket_pending(tls->socket, npending);
 250                 if (*npending == 0) {
 251                         /* seems to be a gnutls bug */
 252                         (*npending) = 100;
 253                 }
 254                 return status;
 255         }
 256         return NT_STATUS_OK;
 257 }
 258
 259 /*
 260   receive data either by tls or normal socket_recv
 261 */
 262 static NTSTATUS tls_socket_recv(struct socket_context *sock, void *buf,
 263                                 size_t wantlen, size_t *nread)
 264 {
 265         int ret;
 266         NTSTATUS status;
 267         struct tls_context *tls = talloc_get_type(sock->private_data, struct tls_context);
 268
 269         if (tls->tls_enabled && tls->tls_detect) {
 270                 status = socket_recv(tls->socket, &tls->first_byte, 1, nread);
 271                 NT_STATUS_NOT_OK_RETURN(status);
 272                 if (*nread == 0) return NT_STATUS_OK;
 273                 tls->tls_detect = False;
 274                 /* look for the first byte of a valid HTTP operation */
 275                 if (strchr(tls->plain_chars, tls->first_byte)) {
 276                         /* not a tls link */
 277                         tls->tls_enabled = False;
 278                         *(uint8_t *)buf = tls->first_byte;
 279                         return NT_STATUS_OK;
 280                 }
 281                 tls->have_first_byte = True;
 282         }
 283
 284         if (!tls->tls_enabled) {
 285                 return socket_recv(tls->socket, buf, wantlen, nread);
 286         }
 287
 288         status = tls_handshake(tls);
 289         NT_STATUS_NOT_OK_RETURN(status);
 290
 291         status = tls_interrupted(tls);
 292         NT_STATUS_NOT_OK_RETURN(status);
 293
 294         ret = gnutls_record_recv(tls->session, buf, wantlen);
 295         if (ret == GNUTLS_E_INTERRUPTED || ret == GNUTLS_E_AGAIN) {
 296                 if (gnutls_record_get_direction(tls->session) == 1) {
 297                         EVENT_FD_WRITEABLE(tls->fde);
 298                 }
 299                 tls->interrupted = True;
 300                 return STATUS_MORE_ENTRIES;
 301         }
 302         if (ret < 0) {
 303                 return NT_STATUS_UNEXPECTED_NETWORK_ERROR;
 304         }
 305         *nread = ret;
 306         return NT_STATUS_OK;
 307 }
 308
 309
 310 /*
 311   send data either by tls or normal socket_recv
 312 */
 313 static NTSTATUS tls_socket_send(struct socket_context *sock,
 314                                 const DATA_BLOB *blob, size_t *sendlen)
 315 {
 316         NTSTATUS status;
 317         int ret;
 318         struct tls_context *tls = talloc_get_type(sock->private_data, struct tls_context);
 319
 320         if (!tls->tls_enabled) {
 321                 return socket_send(tls->socket, blob, sendlen);
 322         }
 323
 324         status = tls_handshake(tls);
 325         NT_STATUS_NOT_OK_RETURN(status);
 326
 327         status = tls_interrupted(tls);
 328         NT_STATUS_NOT_OK_RETURN(status);
 329
 330         ret = gnutls_record_send(tls->session, blob->data, blob->length);
 331         if (ret == GNUTLS_E_INTERRUPTED || ret == GNUTLS_E_AGAIN) {
 332                 if (gnutls_record_get_direction(tls->session) == 1) {
 333                         EVENT_FD_WRITEABLE(tls->fde);
 334                 }
 335                 tls->interrupted = True;
 336                 return STATUS_MORE_ENTRIES;
 337         }
 338         if (ret < 0) {
 339                 DEBUG(0,("gnutls_record_send of %d failed - %s\n", blob->length, gnutls_strerror(ret)));
 340                 return NT_STATUS_UNEXPECTED_NETWORK_ERROR;
 341         }
 342         *sendlen = ret;
 343         tls->output_pending = (ret < blob->length);
 344         return NT_STATUS_OK;
 345 }
 346
 347
 348 /*
 349   initialise global tls state
 350 */
 351 struct tls_params *tls_initialise(TALLOC_CTX *mem_ctx)
 352 {
 353         struct tls_params *params;
 354         int ret;
 355         TALLOC_CTX *tmp_ctx = talloc_new(mem_ctx);
 356         const char *keyfile = private_path(tmp_ctx, lp_tls_keyfile());
 357         const char *certfile = private_path(tmp_ctx, lp_tls_certfile());
 358         const char *cafile = private_path(tmp_ctx, lp_tls_cafile());
 359         const char *crlfile = private_path(tmp_ctx, lp_tls_crlfile());
 360         void tls_cert_generate(TALLOC_CTX *, const char *, const char *, const char *);
 361
 362         params = talloc(mem_ctx, struct tls_params);
 363         if (params == NULL) {
 364                 talloc_free(tmp_ctx);
 365                 return NULL;
 366         }
 367
 368         if (!lp_tls_enabled() || keyfile == NULL || *keyfile == 0) {
 369                 params->tls_enabled = False;
 370                 talloc_free(tmp_ctx);
 371                 return params;
 372         }
 373
 374         if (!file_exist(cafile)) {
 375                 tls_cert_generate(params, keyfile, certfile, cafile);
 376         }
 377
 378         ret = gnutls_global_init();
 379         if (ret < 0) goto init_failed;
 380
 381         gnutls_certificate_allocate_credentials(&params->x509_cred);
 382         if (ret < 0) goto init_failed;
 383
 384         if (cafile && *cafile) {
 385                 ret = gnutls_certificate_set_x509_trust_file(params->x509_cred, cafile,
 386                                                              GNUTLS_X509_FMT_PEM);
 387                 if (ret < 0) {
 388                         DEBUG(0,("TLS failed to initialise cafile %s\n", cafile));
 389                         goto init_failed;
 390                 }
 391         }
 392
 393         if (crlfile && *crlfile) {
 394                 ret = gnutls_certificate_set_x509_crl_file(params->x509_cred,
 395                                                            crlfile,
 396                                                            GNUTLS_X509_FMT_PEM);
 397                 if (ret < 0) {
 398                         DEBUG(0,("TLS failed to initialise crlfile %s\n", crlfile));
 399                         goto init_failed;
 400                 }
 401         }
 402
 403         ret = gnutls_certificate_set_x509_key_file(params->x509_cred,
 404                                                    certfile, keyfile,
 405                                                    GNUTLS_X509_FMT_PEM);
 406         if (ret < 0) {
 407                 DEBUG(0,("TLS failed to initialise certfile %s and keyfile %s\n",
 408                          certfile, keyfile));
 409                 goto init_failed;
 410         }
 411
 412         ret = gnutls_dh_params_init(&params->dh_params);
 413         if (ret < 0) goto init_failed;
 414
 415         ret = gnutls_dh_params_generate2(params->dh_params, DH_BITS);
 416         if (ret < 0) goto init_failed;
 417
 418         gnutls_certificate_set_dh_params(params->x509_cred, params->dh_params);
 419
 420         params->tls_enabled = True;
 421
 422         talloc_free(tmp_ctx);
 423         return params;
 424
 425 init_failed:
 426         DEBUG(0,("GNUTLS failed to initialise - %s\n", gnutls_strerror(ret)));
 427         params->tls_enabled = False;
 428         talloc_free(tmp_ctx);
 429         return params;
 430 }
 431
 432
 433 /*
 434   setup for a new connection
 435 */
 436 struct socket_context *tls_init_server(struct tls_params *params,
 437                                     struct socket_context *socket,
 438                                     struct fd_event *fde,
 439                                     const char *plain_chars)
 440 {
 441         struct tls_context *tls;
 442         int ret;
 443         struct socket_context *new_sock;
 444         NTSTATUS nt_status;
 445
 446         nt_status = socket_create_with_ops(socket, &tls_socket_ops, &new_sock,
 447                                            SOCKET_TYPE_STREAM, 0);
 448         if (!NT_STATUS_IS_OK(nt_status)) {
 449                 return NULL;
 450         }
 451
 452         tls = talloc(new_sock, struct tls_context);
 453         if (tls == NULL) {
 454                 return NULL;
 455         }
 456
 457         tls->socket          = socket;
 458         tls->fde             = fde;
 459         if (talloc_reference(tls, fde) == NULL) {
 460                 return NULL;
 461         }
 462         if (talloc_reference(tls, socket) == NULL) {
 463                 return NULL;
 464         }
 465
 466         new_sock->private_data    = tls;
 467
 468         if (!params->tls_enabled) {
 469                 tls->tls_enabled = False;
 470                 return new_sock;
 471         }
 472
 473         TLSCHECK(gnutls_init(&tls->session, GNUTLS_SERVER));
 474
 475         talloc_set_destructor(tls, tls_destructor);
 476
 477         TLSCHECK(gnutls_set_default_priority(tls->session));
 478         TLSCHECK(gnutls_credentials_set(tls->session, GNUTLS_CRD_CERTIFICATE,
 479                                         params->x509_cred));
 480         gnutls_certificate_server_set_request(tls->session, GNUTLS_CERT_REQUEST);
 481         gnutls_dh_set_prime_bits(tls->session, DH_BITS);
 482         gnutls_transport_set_ptr(tls->session, (gnutls_transport_ptr)tls);
 483         gnutls_transport_set_pull_function(tls->session, (gnutls_pull_func)tls_pull);
 484         gnutls_transport_set_push_function(tls->session, (gnutls_push_func)tls_push);
 485         gnutls_transport_set_lowat(tls->session, 0);
 486
 487         tls->plain_chars = plain_chars;
 488         if (plain_chars) {
 489                 tls->tls_detect = True;
 490         } else {
 491                 tls->tls_detect = False;
 492         }
 493
 494         tls->output_pending  = False;
 495         tls->done_handshake  = False;
 496         tls->have_first_byte = False;
 497         tls->tls_enabled     = True;
 498         tls->interrupted     = False;
 499
 500         new_sock->state = SOCKET_STATE_SERVER_CONNECTED;
 501
 502         return new_sock;
 503
 504 failed:
 505         DEBUG(0,("TLS init connection failed - %s\n", gnutls_strerror(ret)));
 506         tls->tls_enabled = False;
 507         params->tls_enabled = False;
 508         return new_sock;
 509 }
 510
 511
 512 /*
 513   setup for a new client connection
 514 */
 515 struct socket_context *tls_init_client(struct socket_context *socket,
 516                                        struct fd_event *fde)
 517 {
 518         struct tls_context *tls;
 519         int ret = 0;
 520         const int cert_type_priority[] = { GNUTLS_CRT_X509, GNUTLS_CRT_OPENPGP, 0 };
 521         char *cafile;
 522         struct socket_context *new_sock;
 523         NTSTATUS nt_status;
 524
 525         nt_status = socket_create_with_ops(socket, &tls_socket_ops, &new_sock,
 526                                            SOCKET_TYPE_STREAM, 0);
 527         if (!NT_STATUS_IS_OK(nt_status)) {
 528                 return NULL;
 529         }
 530
 531         tls = talloc(new_sock, struct tls_context);
 532         if (tls == NULL) return NULL;
 533
 534         tls->socket          = socket;
 535         tls->fde             = fde;
 536         if (talloc_reference(tls, fde) == NULL) {
 537                 return NULL;
 538         }
 539         if (talloc_reference(tls, socket) == NULL) {
 540                 return NULL;
 541         }
 542         new_sock->private_data    = tls;
 543
 544         cafile = private_path(tls, lp_tls_cafile());
 545         if (!cafile || !*cafile) {
 546                 goto failed;
 547         }
 548
 549         gnutls_global_init();
 550
 551         gnutls_certificate_allocate_credentials(&tls->xcred);
 552         gnutls_certificate_set_x509_trust_file(tls->xcred, cafile, GNUTLS_X509_FMT_PEM);
 553         talloc_free(cafile);
 554         TLSCHECK(gnutls_init(&tls->session, GNUTLS_CLIENT));
 555         TLSCHECK(gnutls_set_default_priority(tls->session));
 556         gnutls_certificate_type_set_priority(tls->session, cert_type_priority);
 557         TLSCHECK(gnutls_credentials_set(tls->session, GNUTLS_CRD_CERTIFICATE, tls->xcred));
 558
 559         talloc_set_destructor(tls, tls_destructor);
 560
 561         gnutls_transport_set_ptr(tls->session, (gnutls_transport_ptr)tls);
 562         gnutls_transport_set_pull_function(tls->session, (gnutls_pull_func)tls_pull);
 563         gnutls_transport_set_push_function(tls->session, (gnutls_push_func)tls_push);
 564         gnutls_transport_set_lowat(tls->session, 0);
 565         tls->tls_detect = False;
 566
 567         tls->output_pending  = False;
 568         tls->done_handshake  = False;
 569         tls->have_first_byte = False;
 570         tls->tls_enabled     = True;
 571         tls->interrupted     = False;
 572
 573         new_sock->state = SOCKET_STATE_CLIENT_CONNECTED;
 574
 575         return new_sock;
 576
 577 failed:
 578         DEBUG(0,("TLS init connection failed - %s\n", gnutls_strerror(ret)));
 579         tls->tls_enabled = False;
 580         return new_sock;
 581 }
 582
 583 static NTSTATUS tls_socket_set_option(struct socket_context *sock, const char *option, const char *val)
 584 {
 585         set_socket_options(socket_get_fd(sock), option);
 586         return NT_STATUS_OK;
 587 }
 588
 589 static char *tls_socket_get_peer_name(struct socket_context *sock, TALLOC_CTX *mem_ctx)
 590 {
 591         struct tls_context *tls = talloc_get_type(sock->private_data, struct tls_context);
 592         return socket_get_peer_name(tls->socket, mem_ctx);
 593 }
 594
 595 static struct socket_address *tls_socket_get_peer_addr(struct socket_context *sock, TALLOC_CTX *mem_ctx)
 596 {
 597         struct tls_context *tls = talloc_get_type(sock->private_data, struct tls_context);
 598         return socket_get_peer_addr(tls->socket, mem_ctx);
 599 }
 600
 601 static struct socket_address *tls_socket_get_my_addr(struct socket_context *sock, TALLOC_CTX *mem_ctx)
 602 {
 603         struct tls_context *tls = talloc_get_type(sock->private_data, struct tls_context);
 604         return socket_get_my_addr(tls->socket, mem_ctx);
 605 }
 606
 607 static int tls_socket_get_fd(struct socket_context *sock)
 608 {
 609         struct tls_context *tls = talloc_get_type(sock->private_data, struct tls_context);
 610         return socket_get_fd(tls->socket);
 611 }
 612
 613 static const struct socket_ops tls_socket_ops = {
 614         .name                   = "tls",
 615         .fn_init                = tls_socket_init,
 616         .fn_recv                = tls_socket_recv,
 617         .fn_send                = tls_socket_send,
 618         .fn_pending             = tls_socket_pending,
 619
 620         .fn_set_option          = tls_socket_set_option,
 621
 622         .fn_get_peer_name       = tls_socket_get_peer_name,
 623         .fn_get_peer_addr       = tls_socket_get_peer_addr,
 624         .fn_get_my_addr         = tls_socket_get_my_addr,
 625         .fn_get_fd              = tls_socket_get_fd
 626 };
 627
 628 BOOL tls_support(struct tls_params *params)
 629 {
 630         return params->tls_enabled;
 631 }
 632
 633 #else
 634
 635 /* for systems without tls we just map the tls socket calls to the
 636    normal socket calls */
 637
 638 struct tls_params *tls_initialise(TALLOC_CTX *mem_ctx)
 639 {
 640         return talloc_new(mem_ctx);
 641 }
 642
 643 /*
 644   setup for a new connection
 645 */
 646 struct socket_context *tls_init_server(struct tls_params *params,
 647                                     struct socket_context *socket,
 648                                     struct fd_event *fde,
 649                                     const char *plain_chars)
 650 {
 651         return socket;
 652 }
 653
 654
 655 /*
 656   setup for a new client connection
 657 */
 658 struct socket_context *tls_init_client(struct socket_context *socket,
 659                                        struct fd_event *fde)
 660 {
 661         return socket;
 662 }
 663
 664 BOOL tls_support(struct tls_params *params)
 665 {
 666         return False;
 667 }
 668
 669 #endif
 670