source4/lib/tls/tls.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    transport layer security handling code
   5
   6    Copyright (C) Andrew Tridgell 2005
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21 */
  22
  23 #include "includes.h"
  24 #include "lib/events/events.h"
  25 #include "lib/socket/socket.h"
  26 #include "lib/tls/tls.h"
  27
  28 #if HAVE_LIBGNUTLS
  29 #include "gnutls/gnutls.h"
  30
  31 #define DH_BITS 1024
  32
  33 /* hold persistent tls data */
  34 struct tls_params {
  35         gnutls_certificate_credentials x509_cred;
  36         gnutls_dh_params dh_params;
  37         BOOL tls_enabled;
  38 };
  39
  40 /* hold per connection tls data */
  41 struct tls_context {
  42         struct tls_params *params;
  43         struct socket_context *socket;
  44         struct fd_event *fde;
  45         gnutls_session session;
  46         BOOL done_handshake;
  47         BOOL have_first_byte;
  48         uint8_t first_byte;
  49         BOOL tls_enabled;
  50         BOOL tls_detect;
  51         const char *plain_chars;
  52         BOOL output_pending;
  53 };
  54
  55
  56 /*
  57   callback for reading from a socket
  58 */
  59 static ssize_t tls_pull(gnutls_transport_ptr ptr, void *buf, size_t size)
  60 {
  61         struct tls_context *tls = talloc_get_type(ptr, struct tls_context);
  62         NTSTATUS status;
  63         size_t nread;
  64
  65         if (tls->have_first_byte) {
  66                 *(uint8_t *)buf = tls->first_byte;
  67                 tls->have_first_byte = False;
  68                 return 1;
  69         }
  70
  71         status = socket_recv(tls->socket, buf, size, &nread, 0);
  72         if (NT_STATUS_EQUAL(status, NT_STATUS_END_OF_FILE)) {
  73                 return 0;
  74         }
  75         if (NT_STATUS_IS_ERR(status)) {
  76                 EVENT_FD_NOT_READABLE(tls->fde);
  77                 EVENT_FD_NOT_WRITEABLE(tls->fde);
  78                 errno = EBADF;
  79                 return -1;
  80         }
  81         if (!NT_STATUS_IS_OK(status)) {
  82                 EVENT_FD_READABLE(tls->fde);
  83                 EVENT_FD_NOT_WRITEABLE(tls->fde);
  84                 errno = EAGAIN;
  85                 return -1;
  86         }
  87         if (tls->output_pending) {
  88                 EVENT_FD_WRITEABLE(tls->fde);
  89         }
  90         if (size != nread) {
  91                 EVENT_FD_READABLE(tls->fde);
  92         }
  93         return nread;
  94 }
  95
  96 /*
  97   callback for writing to a socket
  98 */
  99 static ssize_t tls_push(gnutls_transport_ptr ptr, const void *buf, size_t size)
 100 {
 101         struct tls_context *tls = talloc_get_type(ptr, struct tls_context);
 102         NTSTATUS status;
 103         size_t nwritten;
 104         DATA_BLOB b;
 105
 106         if (!tls->tls_enabled) {
 107                 return size;
 108         }
 109
 110         b.data = discard_const(buf);
 111         b.length = size;
 112
 113         status = socket_send(tls->socket, &b, &nwritten, 0);
 114         if (NT_STATUS_EQUAL(status, STATUS_MORE_ENTRIES)) {
 115                 errno = EAGAIN;
 116                 return -1;
 117         }
 118         if (!NT_STATUS_IS_OK(status)) {
 119                 EVENT_FD_WRITEABLE(tls->fde);
 120                 return -1;
 121         }
 122         if (size != nwritten) {
 123                 EVENT_FD_WRITEABLE(tls->fde);
 124         }
 125         return nwritten;
 126 }
 127
 128 /*
 129   destroy a tls session
 130  */
 131 static int tls_destructor(void *ptr)
 132 {
 133         struct tls_context *tls = talloc_get_type(ptr, struct tls_context);
 134         int ret;
 135         ret = gnutls_bye(tls->session, GNUTLS_SHUT_WR);
 136         if (ret < 0) {
 137                 DEBUG(0,("TLS gnutls_bye failed - %s\n", gnutls_strerror(ret)));
 138         }
 139         return 0;
 140 }
 141
 142
 143 /*
 144   possibly continue the handshake process
 145 */
 146 static NTSTATUS tls_handshake(struct tls_context *tls)
 147 {
 148         int ret;
 149
 150         if (tls->done_handshake) {
 151                 return NT_STATUS_OK;
 152         }
 153
 154         ret = gnutls_handshake(tls->session);
 155         if (ret == GNUTLS_E_INTERRUPTED || ret == GNUTLS_E_AGAIN) {
 156                 return STATUS_MORE_ENTRIES;
 157         }
 158         if (ret < 0) {
 159                 DEBUG(0,("TLS gnutls_handshake failed - %s\n", gnutls_strerror(ret)));
 160                 return NT_STATUS_UNEXPECTED_NETWORK_ERROR;
 161         }
 162         tls->done_handshake = True;
 163         return NT_STATUS_OK;
 164 }
 165
 166 /*
 167   see how many bytes are pending on the connection
 168 */
 169 NTSTATUS tls_socket_pending(struct tls_context *tls, size_t *npending)
 170 {
 171         if (!tls->tls_enabled || tls->tls_detect) {
 172                 return socket_pending(tls->socket, npending);
 173         }
 174         *npending = gnutls_record_check_pending(tls->session);
 175         if (*npending == 0) {
 176                 return socket_pending(tls->socket, npending);
 177         }
 178         return NT_STATUS_OK;
 179 }
 180
 181 /*
 182   receive data either by tls or normal socket_recv
 183 */
 184 NTSTATUS tls_socket_recv(struct tls_context *tls, void *buf, size_t wantlen,
 185                          size_t *nread)
 186 {
 187         int ret;
 188         NTSTATUS status;
 189         if (tls->tls_enabled && tls->tls_detect) {
 190                 status = socket_recv(tls->socket, &tls->first_byte, 1, nread, 0);
 191                 NT_STATUS_NOT_OK_RETURN(status);
 192                 if (*nread == 0) return NT_STATUS_OK;
 193                 tls->tls_detect = False;
 194                 /* look for the first byte of a valid HTTP operation */
 195                 if (strchr(tls->plain_chars, tls->first_byte)) {
 196                         /* not a tls link */
 197                         tls->tls_enabled = False;
 198                         *(uint8_t *)buf = tls->first_byte;
 199                         return NT_STATUS_OK;
 200                 }
 201                 tls->have_first_byte = True;
 202         }
 203
 204         if (!tls->tls_enabled) {
 205                 return socket_recv(tls->socket, buf, wantlen, nread, 0);
 206         }
 207
 208         status = tls_handshake(tls);
 209         NT_STATUS_NOT_OK_RETURN(status);
 210
 211         ret = gnutls_record_recv(tls->session, buf, wantlen);
 212         if (ret == GNUTLS_E_INTERRUPTED || ret == GNUTLS_E_AGAIN) {
 213                 return STATUS_MORE_ENTRIES;
 214         }
 215         if (ret < 0) {
 216                 return NT_STATUS_UNEXPECTED_NETWORK_ERROR;
 217         }
 218         *nread = ret;
 219         return NT_STATUS_OK;
 220 }
 221
 222
 223 /*
 224   send data either by tls or normal socket_recv
 225 */
 226 NTSTATUS tls_socket_send(struct tls_context *tls, const DATA_BLOB *blob, size_t *sendlen)
 227 {
 228         NTSTATUS status;
 229         int ret;
 230
 231         if (!tls->tls_enabled) {
 232                 return socket_send(tls->socket, blob, sendlen, 0);
 233         }
 234
 235         status = tls_handshake(tls);
 236         NT_STATUS_NOT_OK_RETURN(status);
 237
 238         ret = gnutls_record_send(tls->session, blob->data, blob->length);
 239         if (ret == GNUTLS_E_INTERRUPTED || ret == GNUTLS_E_AGAIN) {
 240                 return STATUS_MORE_ENTRIES;
 241         }
 242         if (ret < 0) {
 243                 DEBUG(0,("gnutls_record_send of %d failed - %s\n", blob->length, gnutls_strerror(ret)));
 244                 return NT_STATUS_UNEXPECTED_NETWORK_ERROR;
 245         }
 246         *sendlen = ret;
 247         tls->output_pending = (ret < blob->length);
 248         return NT_STATUS_OK;
 249 }
 250
 251
 252 /*
 253   initialise global tls state
 254 */
 255 struct tls_params *tls_initialise(TALLOC_CTX *mem_ctx)
 256 {
 257         struct tls_params *params;
 258         int ret;
 259         const char *keyfile = lp_tls_keyfile();
 260         const char *certfile = lp_tls_certfile();
 261         const char *cafile = lp_tls_cafile();
 262         const char *crlfile = lp_tls_crlfile();
 263         void tls_cert_generate(TALLOC_CTX *, const char *, const char *, const char *);
 264
 265         params = talloc(mem_ctx, struct tls_params);
 266         if (params == NULL) return NULL;
 267
 268         if (!lp_tls_enabled() || keyfile == NULL || *keyfile == 0) {
 269                 params->tls_enabled = False;
 270                 return params;
 271         }
 272
 273         if (!file_exist(cafile)) {
 274                 tls_cert_generate(params, keyfile, certfile, cafile);
 275         }
 276
 277         ret = gnutls_global_init();
 278         if (ret < 0) goto init_failed;
 279
 280         gnutls_certificate_allocate_credentials(&params->x509_cred);
 281         if (ret < 0) goto init_failed;
 282
 283         if (cafile && *cafile) {
 284                 ret = gnutls_certificate_set_x509_trust_file(params->x509_cred, cafile,
 285                                                              GNUTLS_X509_FMT_PEM);
 286                 if (ret < 0) {
 287                         DEBUG(0,("TLS failed to initialise cafile %s\n", cafile));
 288                         goto init_failed;
 289                 }
 290         }
 291
 292         if (crlfile && *crlfile) {
 293                 ret = gnutls_certificate_set_x509_crl_file(params->x509_cred,
 294                                                            crlfile,
 295                                                            GNUTLS_X509_FMT_PEM);
 296                 if (ret < 0) {
 297                         DEBUG(0,("TLS failed to initialise crlfile %s\n", crlfile));
 298                         goto init_failed;
 299                 }
 300         }
 301
 302         ret = gnutls_certificate_set_x509_key_file(params->x509_cred,
 303                                                    certfile, keyfile,
 304                                                    GNUTLS_X509_FMT_PEM);
 305         if (ret < 0) {
 306                 DEBUG(0,("TLS failed to initialise certfile %s and keyfile %s\n",
 307                          certfile, keyfile));
 308                 goto init_failed;
 309         }
 310
 311         ret = gnutls_dh_params_init(&params->dh_params);
 312         if (ret < 0) goto init_failed;
 313
 314         ret = gnutls_dh_params_generate2(params->dh_params, DH_BITS);
 315         if (ret < 0) goto init_failed;
 316
 317         gnutls_certificate_set_dh_params(params->x509_cred, params->dh_params);
 318
 319         params->tls_enabled = True;
 320         return params;
 321
 322 init_failed:
 323         DEBUG(0,("GNUTLS failed to initialise - %s\n", gnutls_strerror(ret)));
 324         params->tls_enabled = False;
 325         return params;
 326 }
 327
 328
 329 /*
 330   setup for a new connection
 331 */
 332 struct tls_context *tls_init_server(struct tls_params *params,
 333                                     struct socket_context *socket,
 334                                     struct fd_event *fde,
 335                                     const char *plain_chars)
 336 {
 337         struct tls_context *tls;
 338         int ret;
 339
 340         tls = talloc(socket, struct tls_context);
 341         if (tls == NULL) return NULL;
 342
 343         tls->socket          = socket;
 344         tls->fde             = fde;
 345
 346         if (!params->tls_enabled) {
 347                 tls->tls_enabled = False;
 348                 return tls;
 349         }
 350
 351 #define TLSCHECK(call) do { \
 352         ret = call; \
 353         if (ret < 0) { \
 354                 DEBUG(0,("TLS %s - %s\n", #call, gnutls_strerror(ret))); \
 355                 goto failed; \
 356         } \
 357 } while (0)
 358
 359         TLSCHECK(gnutls_init(&tls->session, GNUTLS_SERVER));
 360
 361         talloc_set_destructor(tls, tls_destructor);
 362
 363         TLSCHECK(gnutls_set_default_priority(tls->session));
 364         TLSCHECK(gnutls_credentials_set(tls->session, GNUTLS_CRD_CERTIFICATE,
 365                                         params->x509_cred));
 366         gnutls_certificate_server_set_request(tls->session, GNUTLS_CERT_REQUEST);
 367         gnutls_dh_set_prime_bits(tls->session, DH_BITS);
 368         gnutls_transport_set_ptr(tls->session, (gnutls_transport_ptr)tls);
 369         gnutls_transport_set_pull_function(tls->session, (gnutls_pull_func)tls_pull);
 370         gnutls_transport_set_push_function(tls->session, (gnutls_push_func)tls_push);
 371         gnutls_transport_set_lowat(tls->session, 0);
 372
 373         tls->plain_chars = plain_chars;
 374         if (plain_chars) {
 375                 tls->tls_detect = True;
 376         } else {
 377                 tls->tls_detect = False;
 378         }
 379
 380         tls->output_pending  = False;
 381         tls->params          = params;
 382         tls->done_handshake  = False;
 383         tls->have_first_byte = False;
 384         tls->tls_enabled     = True;
 385
 386         return tls;
 387
 388 failed:
 389         DEBUG(0,("TLS init connection failed - %s\n", gnutls_strerror(ret)));
 390         tls->tls_enabled = False;
 391         params->tls_enabled = False;
 392         return tls;
 393 }
 394
 395 BOOL tls_enabled(struct tls_context *tls)
 396 {
 397         return tls->tls_enabled;
 398 }
 399
 400 BOOL tls_support(struct tls_params *params)
 401 {
 402         return params->tls_enabled;
 403 }
 404
 405
 406 #else
 407
 408 /* for systems without tls we just map the tls socket calls to the
 409    normal socket calls */
 410
 411 struct tls_params *tls_initialise(TALLOC_CTX *mem_ctx)
 412 {
 413         return talloc_new(mem_ctx);
 414 }
 415
 416 struct tls_context *tls_init_server(struct tls_params *params,
 417                                     struct socket_context *sock,
 418                                     struct fd_event *fde,
 419                                     const char *plain_chars)
 420 {
 421         if (plain_chars == NULL) return NULL;
 422         return (struct tls_context *)sock;
 423 }
 424
 425
 426 NTSTATUS tls_socket_recv(struct tls_context *tls, void *buf, size_t wantlen,
 427                          size_t *nread)
 428 {
 429         return socket_recv((struct socket_context *)tls, buf, wantlen, nread, 0);
 430 }
 431
 432 NTSTATUS tls_socket_send(struct tls_context *tls, const DATA_BLOB *blob, size_t *sendlen)
 433 {
 434         return socket_send((struct socket_context *)tls, blob, sendlen, 0);
 435 }
 436
 437 BOOL tls_enabled(struct tls_context *tls)
 438 {
 439         return False;
 440 }
 441
 442 BOOL tls_support(struct tls_params *params)
 443 {
 444         return False;
 445 }
 446
 447 NTSTATUS tls_socket_pending(struct tls_context *tls, size_t *npending)
 448 {
 449         return socket_pending((struct socket_context *)tls, npending);
 450 }
 451
 452 #endif