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_IS_OK(status)) {
  73                 EVENT_FD_READABLE(tls->fde);
  74                 EVENT_FD_NOT_WRITEABLE(tls->fde);
  75                 return -1;
  76         }
  77         if (tls->output_pending) {
  78                 EVENT_FD_WRITEABLE(tls->fde);
  79         }
  80         if (size != nread) {
  81                 EVENT_FD_READABLE(tls->fde);
  82         }
  83         return nread;
  84 }
  85
  86 /*
  87   callback for writing to a socket
  88 */
  89 static ssize_t tls_push(gnutls_transport_ptr ptr, const void *buf, size_t size)
  90 {
  91         struct tls_context *tls = talloc_get_type(ptr, struct tls_context);
  92         NTSTATUS status;
  93         size_t nwritten;
  94         DATA_BLOB b;
  95
  96         if (!tls->tls_enabled) {
  97                 return size;
  98         }
  99
 100         b.data = discard_const(buf);
 101         b.length = size;
 102
 103         status = socket_send(tls->socket, &b, &nwritten, 0);
 104         if (!NT_STATUS_IS_OK(status)) {
 105                 EVENT_FD_WRITEABLE(tls->fde);
 106                 return -1;
 107         }
 108         if (size != nwritten) {
 109                 EVENT_FD_WRITEABLE(tls->fde);
 110         }
 111         return nwritten;
 112 }
 113
 114 /*
 115   destroy a tls session
 116  */
 117 static int tls_destructor(void *ptr)
 118 {
 119         struct tls_context *tls = talloc_get_type(ptr, struct tls_context);
 120         int ret;
 121         ret = gnutls_bye(tls->session, GNUTLS_SHUT_WR);
 122         if (ret < 0) {
 123                 DEBUG(0,("TLS gnutls_bye failed - %s\n", gnutls_strerror(ret)));
 124         }
 125         return 0;
 126 }
 127
 128
 129 /*
 130   possibly continue the handshake process
 131 */
 132 static NTSTATUS tls_handshake(struct tls_context *tls)
 133 {
 134         int ret;
 135
 136         if (tls->done_handshake) {
 137                 return NT_STATUS_OK;
 138         }
 139
 140         ret = gnutls_handshake(tls->session);
 141         if (ret == GNUTLS_E_INTERRUPTED || ret == GNUTLS_E_AGAIN) {
 142                 return STATUS_MORE_ENTRIES;
 143         }
 144         if (ret < 0) {
 145                 DEBUG(0,("TLS gnutls_handshake failed - %s\n", gnutls_strerror(ret)));
 146                 return NT_STATUS_UNEXPECTED_NETWORK_ERROR;
 147         }
 148         tls->done_handshake = True;
 149         return NT_STATUS_OK;
 150 }
 151
 152
 153 /*
 154   receive data either by tls or normal socket_recv
 155 */
 156 NTSTATUS tls_socket_recv(struct tls_context *tls, void *buf, size_t wantlen,
 157                          size_t *nread)
 158 {
 159         int ret;
 160         NTSTATUS status;
 161         if (tls->tls_enabled && tls->tls_detect) {
 162                 status = socket_recv(tls->socket, &tls->first_byte, 1, nread, 0);
 163                 NT_STATUS_NOT_OK_RETURN(status);
 164                 if (*nread == 0) return NT_STATUS_OK;
 165                 tls->tls_detect = False;
 166                 /* look for the first byte of a valid HTTP operation */
 167                 if (strchr(tls->plain_chars, tls->first_byte)) {
 168                         /* not a tls link */
 169                         tls->tls_enabled = False;
 170                         *(uint8_t *)buf = tls->first_byte;
 171                         return NT_STATUS_OK;
 172                 }
 173                 tls->have_first_byte = True;
 174         }
 175
 176         if (!tls->tls_enabled) {
 177                 return socket_recv(tls->socket, buf, wantlen, nread, 0);
 178         }
 179
 180         status = tls_handshake(tls);
 181         NT_STATUS_NOT_OK_RETURN(status);
 182
 183         ret = gnutls_record_recv(tls->session, buf, wantlen);
 184         if (ret == GNUTLS_E_INTERRUPTED || ret == GNUTLS_E_AGAIN) {
 185                 return STATUS_MORE_ENTRIES;
 186         }
 187         if (ret < 0) {
 188                 DEBUG(0,("gnutls_record_recv failed - %s\n", gnutls_strerror(ret)));
 189                 return NT_STATUS_UNEXPECTED_NETWORK_ERROR;
 190         }
 191         *nread = ret;
 192         return NT_STATUS_OK;
 193 }
 194
 195
 196 /*
 197   send data either by tls or normal socket_recv
 198 */
 199 NTSTATUS tls_socket_send(struct tls_context *tls, const DATA_BLOB *blob, size_t *sendlen)
 200 {
 201         NTSTATUS status;
 202         int ret;
 203
 204         if (!tls->tls_enabled) {
 205                 return socket_send(tls->socket, blob, sendlen, 0);
 206         }
 207
 208         status = tls_handshake(tls);
 209         NT_STATUS_NOT_OK_RETURN(status);
 210
 211         ret = gnutls_record_send(tls->session, blob->data, blob->length);
 212         if (ret == GNUTLS_E_INTERRUPTED || ret == GNUTLS_E_AGAIN) {
 213                 return STATUS_MORE_ENTRIES;
 214         }
 215         if (ret < 0) {
 216                 DEBUG(0,("gnutls_record_send failed - %s\n", gnutls_strerror(ret)));
 217                 return NT_STATUS_UNEXPECTED_NETWORK_ERROR;
 218         }
 219         *sendlen = ret;
 220         tls->output_pending = (ret < blob->length);
 221         return NT_STATUS_OK;
 222 }
 223
 224
 225 /*
 226   initialise global tls state
 227 */
 228 struct tls_params *tls_initialise(TALLOC_CTX *mem_ctx)
 229 {
 230         struct tls_params *params;
 231         int ret;
 232         const char *keyfile = lp_tls_keyfile();
 233         const char *certfile = lp_tls_certfile();
 234         const char *cafile = lp_tls_cafile();
 235         const char *crlfile = lp_tls_crlfile();
 236         void tls_cert_generate(TALLOC_CTX *, const char *, const char *, const char *);
 237
 238         params = talloc(mem_ctx, struct tls_params);
 239         if (params == NULL) return NULL;
 240
 241         if (!lp_tls_enabled() || keyfile == NULL || *keyfile == 0) {
 242                 params->tls_enabled = False;
 243                 return params;
 244         }
 245
 246         if (!file_exist(cafile)) {
 247                 tls_cert_generate(params, keyfile, certfile, cafile);
 248         }
 249
 250         ret = gnutls_global_init();
 251         if (ret < 0) goto init_failed;
 252
 253         gnutls_certificate_allocate_credentials(&params->x509_cred);
 254         if (ret < 0) goto init_failed;
 255
 256         if (cafile && *cafile) {
 257                 ret = gnutls_certificate_set_x509_trust_file(params->x509_cred, cafile,
 258                                                              GNUTLS_X509_FMT_PEM);
 259                 if (ret < 0) {
 260                         DEBUG(0,("TLS failed to initialise cafile %s\n", cafile));
 261                         goto init_failed;
 262                 }
 263         }
 264
 265         if (crlfile && *crlfile) {
 266                 ret = gnutls_certificate_set_x509_crl_file(params->x509_cred,
 267                                                            crlfile,
 268                                                            GNUTLS_X509_FMT_PEM);
 269                 if (ret < 0) {
 270                         DEBUG(0,("TLS failed to initialise crlfile %s\n", crlfile));
 271                         goto init_failed;
 272                 }
 273         }
 274
 275         ret = gnutls_certificate_set_x509_key_file(params->x509_cred,
 276                                                    certfile, keyfile,
 277                                                    GNUTLS_X509_FMT_PEM);
 278         if (ret < 0) {
 279                 DEBUG(0,("TLS failed to initialise certfile %s and keyfile %s\n",
 280                          certfile, keyfile));
 281                 goto init_failed;
 282         }
 283
 284         ret = gnutls_dh_params_init(&params->dh_params);
 285         if (ret < 0) goto init_failed;
 286
 287         ret = gnutls_dh_params_generate2(params->dh_params, DH_BITS);
 288         if (ret < 0) goto init_failed;
 289
 290         gnutls_certificate_set_dh_params(params->x509_cred, params->dh_params);
 291
 292         params->tls_enabled = True;
 293         return params;
 294
 295 init_failed:
 296         DEBUG(0,("GNUTLS failed to initialise - %s\n", gnutls_strerror(ret)));
 297         params->tls_enabled = False;
 298         return params;
 299 }
 300
 301
 302 /*
 303   setup for a new connection
 304 */
 305 struct tls_context *tls_init_server(struct tls_params *params,
 306                                     struct socket_context *socket,
 307                                     struct fd_event *fde,
 308                                     const char *plain_chars)
 309 {
 310         struct tls_context *tls;
 311         int ret;
 312
 313         tls = talloc(socket, struct tls_context);
 314         if (tls == NULL) return NULL;
 315
 316         tls->socket          = socket;
 317         tls->fde             = fde;
 318
 319         if (!params->tls_enabled) {
 320                 tls->tls_enabled = False;
 321                 return tls;
 322         }
 323
 324 #define TLSCHECK(call) do { \
 325         ret = call; \
 326         if (ret < 0) { \
 327                 DEBUG(0,("TLS %s - %s\n", #call, gnutls_strerror(ret))); \
 328                 goto failed; \
 329         } \
 330 } while (0)
 331
 332         TLSCHECK(gnutls_init(&tls->session, GNUTLS_SERVER));
 333
 334         talloc_set_destructor(tls, tls_destructor);
 335
 336         TLSCHECK(gnutls_set_default_priority(tls->session));
 337         TLSCHECK(gnutls_credentials_set(tls->session, GNUTLS_CRD_CERTIFICATE,
 338                                         params->x509_cred));
 339         gnutls_certificate_server_set_request(tls->session, GNUTLS_CERT_REQUEST);
 340         gnutls_dh_set_prime_bits(tls->session, DH_BITS);
 341         gnutls_transport_set_ptr(tls->session, (gnutls_transport_ptr)tls);
 342         gnutls_transport_set_pull_function(tls->session, (gnutls_pull_func)tls_pull);
 343         gnutls_transport_set_push_function(tls->session, (gnutls_push_func)tls_push);
 344         gnutls_transport_set_lowat(tls->session, 0);
 345
 346         tls->plain_chars = plain_chars;
 347         if (plain_chars) {
 348                 tls->tls_detect = True;
 349         } else {
 350                 tls->tls_detect = False;
 351         }
 352
 353         tls->output_pending  = False;
 354         tls->params          = params;
 355         tls->done_handshake  = False;
 356         tls->have_first_byte = False;
 357         tls->tls_enabled     = True;
 358
 359         return tls;
 360
 361 failed:
 362         DEBUG(0,("TLS init connection failed - %s\n", gnutls_strerror(ret)));
 363         tls->tls_enabled = False;
 364         params->tls_enabled = False;
 365         return tls;
 366 }
 367
 368 BOOL tls_enabled(struct tls_context *tls)
 369 {
 370         return tls->tls_enabled;
 371 }
 372
 373 BOOL tls_support(struct tls_params *params)
 374 {
 375         return params->tls_enabled;
 376 }
 377
 378
 379 #else
 380
 381 /* for systems without tls we just map the tls socket calls to the
 382    normal socket calls */
 383
 384 struct tls_params *tls_initialise(TALLOC_CTX *mem_ctx)
 385 {
 386         return talloc_new(mem_ctx);
 387 }
 388
 389 struct tls_context *tls_init_server(struct tls_params *params,
 390                                     struct socket_context *sock,
 391                                     struct fd_event *fde,
 392                                     const char *plain_chars)
 393 {
 394         if (plain_chars == NULL) return NULL;
 395         return (struct tls_context *)sock;
 396 }
 397
 398
 399 NTSTATUS tls_socket_recv(struct tls_context *tls, void *buf, size_t wantlen,
 400                          size_t *nread)
 401 {
 402         return socket_recv((struct socket_context *)tls, buf, wantlen, nread, 0);
 403 }
 404
 405 NTSTATUS tls_socket_send(struct tls_context *tls, const DATA_BLOB *blob, size_t *sendlen)
 406 {
 407         return socket_send((struct socket_context *)tls, blob, sendlen, 0);
 408 }
 409
 410 BOOL tls_enabled(struct tls_context *tls)
 411 {
 412         return False;
 413 }
 414
 415 BOOL tls_support(struct tls_params *params)
 416 {
 417         return False;
 418 }
 419
 420 #endif