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_IS_OK(status)) {
 115                 EVENT_FD_WRITEABLE(tls->fde);
 116                 return -1;
 117         }
 118         if (size != nwritten) {
 119                 EVENT_FD_WRITEABLE(tls->fde);
 120         }
 121         return nwritten;
 122 }
 123
 124 /*
 125   destroy a tls session
 126  */
 127 static int tls_destructor(void *ptr)
 128 {
 129         struct tls_context *tls = talloc_get_type(ptr, struct tls_context);
 130         int ret;
 131         ret = gnutls_bye(tls->session, GNUTLS_SHUT_WR);
 132         if (ret < 0) {
 133                 DEBUG(0,("TLS gnutls_bye failed - %s\n", gnutls_strerror(ret)));
 134         }
 135         return 0;
 136 }
 137
 138
 139 /*
 140   possibly continue the handshake process
 141 */
 142 static NTSTATUS tls_handshake(struct tls_context *tls)
 143 {
 144         int ret;
 145
 146         if (tls->done_handshake) {
 147                 return NT_STATUS_OK;
 148         }
 149
 150         ret = gnutls_handshake(tls->session);
 151         if (ret == GNUTLS_E_INTERRUPTED || ret == GNUTLS_E_AGAIN) {
 152                 return STATUS_MORE_ENTRIES;
 153         }
 154         if (ret < 0) {
 155                 DEBUG(0,("TLS gnutls_handshake failed - %s\n", gnutls_strerror(ret)));
 156                 return NT_STATUS_UNEXPECTED_NETWORK_ERROR;
 157         }
 158         tls->done_handshake = True;
 159         return NT_STATUS_OK;
 160 }
 161
 162 /*
 163   see how many bytes are pending on the connection
 164 */
 165 NTSTATUS tls_socket_pending(struct tls_context *tls, size_t *npending)
 166 {
 167         if (!tls->tls_enabled || tls->tls_detect) {
 168                 return socket_pending(tls->socket, npending);
 169         }
 170         *npending = gnutls_record_check_pending(tls->session);
 171         if (*npending == 0) {
 172                 return socket_pending(tls->socket, npending);
 173         }
 174         return NT_STATUS_OK;
 175 }
 176
 177 /*
 178   receive data either by tls or normal socket_recv
 179 */
 180 NTSTATUS tls_socket_recv(struct tls_context *tls, void *buf, size_t wantlen,
 181                          size_t *nread)
 182 {
 183         int ret;
 184         NTSTATUS status;
 185         if (tls->tls_enabled && tls->tls_detect) {
 186                 status = socket_recv(tls->socket, &tls->first_byte, 1, nread, 0);
 187                 NT_STATUS_NOT_OK_RETURN(status);
 188                 if (*nread == 0) return NT_STATUS_OK;
 189                 tls->tls_detect = False;
 190                 /* look for the first byte of a valid HTTP operation */
 191                 if (strchr(tls->plain_chars, tls->first_byte)) {
 192                         /* not a tls link */
 193                         tls->tls_enabled = False;
 194                         *(uint8_t *)buf = tls->first_byte;
 195                         return NT_STATUS_OK;
 196                 }
 197                 tls->have_first_byte = True;
 198         }
 199
 200         if (!tls->tls_enabled) {
 201                 return socket_recv(tls->socket, buf, wantlen, nread, 0);
 202         }
 203
 204         status = tls_handshake(tls);
 205         NT_STATUS_NOT_OK_RETURN(status);
 206
 207         ret = gnutls_record_recv(tls->session, buf, wantlen);
 208         if (ret == GNUTLS_E_INTERRUPTED || ret == GNUTLS_E_AGAIN) {
 209                 return STATUS_MORE_ENTRIES;
 210         }
 211         if (ret < 0) {
 212                 return NT_STATUS_UNEXPECTED_NETWORK_ERROR;
 213         }
 214         *nread = ret;
 215         return NT_STATUS_OK;
 216 }
 217
 218
 219 /*
 220   send data either by tls or normal socket_recv
 221 */
 222 NTSTATUS tls_socket_send(struct tls_context *tls, const DATA_BLOB *blob, size_t *sendlen)
 223 {
 224         NTSTATUS status;
 225         int ret;
 226
 227         if (!tls->tls_enabled) {
 228                 return socket_send(tls->socket, blob, sendlen, 0);
 229         }
 230
 231         status = tls_handshake(tls);
 232         NT_STATUS_NOT_OK_RETURN(status);
 233
 234         ret = gnutls_record_send(tls->session, blob->data, blob->length);
 235         if (ret == GNUTLS_E_INTERRUPTED || ret == GNUTLS_E_AGAIN) {
 236                 return STATUS_MORE_ENTRIES;
 237         }
 238         if (ret < 0) {
 239                 DEBUG(0,("gnutls_record_send of %d failed - %s\n", blob->length, gnutls_strerror(ret)));
 240                 return NT_STATUS_UNEXPECTED_NETWORK_ERROR;
 241         }
 242         *sendlen = ret;
 243         tls->output_pending = (ret < blob->length);
 244         return NT_STATUS_OK;
 245 }
 246
 247
 248 /*
 249   initialise global tls state
 250 */
 251 struct tls_params *tls_initialise(TALLOC_CTX *mem_ctx)
 252 {
 253         struct tls_params *params;
 254         int ret;
 255         const char *keyfile = lp_tls_keyfile();
 256         const char *certfile = lp_tls_certfile();
 257         const char *cafile = lp_tls_cafile();
 258         const char *crlfile = lp_tls_crlfile();
 259         void tls_cert_generate(TALLOC_CTX *, const char *, const char *, const char *);
 260
 261         params = talloc(mem_ctx, struct tls_params);
 262         if (params == NULL) return NULL;
 263
 264         if (!lp_tls_enabled() || keyfile == NULL || *keyfile == 0) {
 265                 params->tls_enabled = False;
 266                 return params;
 267         }
 268
 269         if (!file_exist(cafile)) {
 270                 tls_cert_generate(params, keyfile, certfile, cafile);
 271         }
 272
 273         ret = gnutls_global_init();
 274         if (ret < 0) goto init_failed;
 275
 276         gnutls_certificate_allocate_credentials(&params->x509_cred);
 277         if (ret < 0) goto init_failed;
 278
 279         if (cafile && *cafile) {
 280                 ret = gnutls_certificate_set_x509_trust_file(params->x509_cred, cafile,
 281                                                              GNUTLS_X509_FMT_PEM);
 282                 if (ret < 0) {
 283                         DEBUG(0,("TLS failed to initialise cafile %s\n", cafile));
 284                         goto init_failed;
 285                 }
 286         }
 287
 288         if (crlfile && *crlfile) {
 289                 ret = gnutls_certificate_set_x509_crl_file(params->x509_cred,
 290                                                            crlfile,
 291                                                            GNUTLS_X509_FMT_PEM);
 292                 if (ret < 0) {
 293                         DEBUG(0,("TLS failed to initialise crlfile %s\n", crlfile));
 294                         goto init_failed;
 295                 }
 296         }
 297
 298         ret = gnutls_certificate_set_x509_key_file(params->x509_cred,
 299                                                    certfile, keyfile,
 300                                                    GNUTLS_X509_FMT_PEM);
 301         if (ret < 0) {
 302                 DEBUG(0,("TLS failed to initialise certfile %s and keyfile %s\n",
 303                          certfile, keyfile));
 304                 goto init_failed;
 305         }
 306
 307         ret = gnutls_dh_params_init(&params->dh_params);
 308         if (ret < 0) goto init_failed;
 309
 310         ret = gnutls_dh_params_generate2(params->dh_params, DH_BITS);
 311         if (ret < 0) goto init_failed;
 312
 313         gnutls_certificate_set_dh_params(params->x509_cred, params->dh_params);
 314
 315         params->tls_enabled = True;
 316         return params;
 317
 318 init_failed:
 319         DEBUG(0,("GNUTLS failed to initialise - %s\n", gnutls_strerror(ret)));
 320         params->tls_enabled = False;
 321         return params;
 322 }
 323
 324
 325 /*
 326   setup for a new connection
 327 */
 328 struct tls_context *tls_init_server(struct tls_params *params,
 329                                     struct socket_context *socket,
 330                                     struct fd_event *fde,
 331                                     const char *plain_chars)
 332 {
 333         struct tls_context *tls;
 334         int ret;
 335
 336         tls = talloc(socket, struct tls_context);
 337         if (tls == NULL) return NULL;
 338
 339         tls->socket          = socket;
 340         tls->fde             = fde;
 341
 342         if (!params->tls_enabled) {
 343                 tls->tls_enabled = False;
 344                 return tls;
 345         }
 346
 347 #define TLSCHECK(call) do { \
 348         ret = call; \
 349         if (ret < 0) { \
 350                 DEBUG(0,("TLS %s - %s\n", #call, gnutls_strerror(ret))); \
 351                 goto failed; \
 352         } \
 353 } while (0)
 354
 355         TLSCHECK(gnutls_init(&tls->session, GNUTLS_SERVER));
 356
 357         talloc_set_destructor(tls, tls_destructor);
 358
 359         TLSCHECK(gnutls_set_default_priority(tls->session));
 360         TLSCHECK(gnutls_credentials_set(tls->session, GNUTLS_CRD_CERTIFICATE,
 361                                         params->x509_cred));
 362         gnutls_certificate_server_set_request(tls->session, GNUTLS_CERT_REQUEST);
 363         gnutls_dh_set_prime_bits(tls->session, DH_BITS);
 364         gnutls_transport_set_ptr(tls->session, (gnutls_transport_ptr)tls);
 365         gnutls_transport_set_pull_function(tls->session, (gnutls_pull_func)tls_pull);
 366         gnutls_transport_set_push_function(tls->session, (gnutls_push_func)tls_push);
 367         gnutls_transport_set_lowat(tls->session, 0);
 368
 369         tls->plain_chars = plain_chars;
 370         if (plain_chars) {
 371                 tls->tls_detect = True;
 372         } else {
 373                 tls->tls_detect = False;
 374         }
 375
 376         tls->output_pending  = False;
 377         tls->params          = params;
 378         tls->done_handshake  = False;
 379         tls->have_first_byte = False;
 380         tls->tls_enabled     = True;
 381
 382         return tls;
 383
 384 failed:
 385         DEBUG(0,("TLS init connection failed - %s\n", gnutls_strerror(ret)));
 386         tls->tls_enabled = False;
 387         params->tls_enabled = False;
 388         return tls;
 389 }
 390
 391 BOOL tls_enabled(struct tls_context *tls)
 392 {
 393         return tls->tls_enabled;
 394 }
 395
 396 BOOL tls_support(struct tls_params *params)
 397 {
 398         return params->tls_enabled;
 399 }
 400
 401
 402 #else
 403
 404 /* for systems without tls we just map the tls socket calls to the
 405    normal socket calls */
 406
 407 struct tls_params *tls_initialise(TALLOC_CTX *mem_ctx)
 408 {
 409         return talloc_new(mem_ctx);
 410 }
 411
 412 struct tls_context *tls_init_server(struct tls_params *params,
 413                                     struct socket_context *sock,
 414                                     struct fd_event *fde,
 415                                     const char *plain_chars)
 416 {
 417         if (plain_chars == NULL) return NULL;
 418         return (struct tls_context *)sock;
 419 }
 420
 421
 422 NTSTATUS tls_socket_recv(struct tls_context *tls, void *buf, size_t wantlen,
 423                          size_t *nread)
 424 {
 425         return socket_recv((struct socket_context *)tls, buf, wantlen, nread, 0);
 426 }
 427
 428 NTSTATUS tls_socket_send(struct tls_context *tls, const DATA_BLOB *blob, size_t *sendlen)
 429 {
 430         return socket_send((struct socket_context *)tls, blob, sendlen, 0);
 431 }
 432
 433 BOOL tls_enabled(struct tls_context *tls)
 434 {
 435         return False;
 436 }
 437
 438 BOOL tls_support(struct tls_params *params)
 439 {
 440         return False;
 441 }
 442
 443 NTSTATUS tls_socket_pending(struct tls_context *tls, size_t *npending)
 444 {
 445         return socket_pending((struct socket_context *)tls, npending);
 446 }
 447
 448 #endif