source/libsmb/async_smb.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Infrastructure for async SMB client requests
   4    Copyright (C) Volker Lendecke 2008
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 #include "includes.h"
  21
  22 /*
  23  * Fetch an error out of a NBT packet
  24  */
  25
  26 NTSTATUS cli_pull_error(char *buf)
  27 {
  28         uint32_t flags2 = SVAL(buf, smb_flg2);
  29
  30         if (flags2 & FLAGS2_32_BIT_ERROR_CODES) {
  31                 return NT_STATUS(IVAL(buf, smb_rcls));
  32         }
  33
  34         /* if the client uses dos errors, but there is no error,
  35            we should return no error here, otherwise it looks
  36            like an unknown bad NT_STATUS. jmcd */
  37         if (CVAL(buf, smb_rcls) == 0)
  38                 return NT_STATUS_OK;
  39
  40         return NT_STATUS_DOS(CVAL(buf, smb_rcls), SVAL(buf,smb_err));
  41 }
  42
  43 /*
  44  * Compatibility helper for the sync APIs: Fake NTSTATUS in cli->inbuf
  45  */
  46
  47 void cli_set_error(struct cli_state *cli, NTSTATUS status)
  48 {
  49         uint32_t flags2 = SVAL(cli->inbuf, smb_flg2);
  50
  51         if (NT_STATUS_IS_DOS(status)) {
  52                 SSVAL(cli->inbuf, smb_flg2,
  53                       flags2 & ~FLAGS2_32_BIT_ERROR_CODES);
  54                 SCVAL(cli->inbuf, smb_rcls, NT_STATUS_DOS_CLASS(status));
  55                 SSVAL(cli->inbuf, smb_err, NT_STATUS_DOS_CODE(status));
  56                 return;
  57         }
  58
  59         SSVAL(cli->inbuf, smb_flg2, flags2 | FLAGS2_32_BIT_ERROR_CODES);
  60         SIVAL(cli->inbuf, smb_rcls, NT_STATUS_V(status));
  61         return;
  62 }
  63
  64 /*
  65  * Allocate a new mid
  66  */
  67
  68 static uint16_t cli_new_mid(struct cli_state *cli)
  69 {
  70         uint16_t result;
  71         struct cli_request *req;
  72
  73         while (true) {
  74                 result = cli->mid++;
  75                 if (result == 0) {
  76                         continue;
  77                 }
  78
  79                 for (req = cli->outstanding_requests; req; req = req->next) {
  80                         if (result == req->mid) {
  81                                 break;
  82                         }
  83                 }
  84
  85                 if (req == NULL) {
  86                         return result;
  87                 }
  88         }
  89 }
  90
  91 static char *cli_request_print(TALLOC_CTX *mem_ctx, struct async_req *req)
  92 {
  93         char *result = async_req_print(mem_ctx, req);
  94         struct cli_request *cli_req = cli_request_get(req);
  95
  96         if (result == NULL) {
  97                 return NULL;
  98         }
  99
 100         return talloc_asprintf_append_buffer(
 101                 result, "mid=%d\n", cli_req->mid);
 102 }
 103
 104 static int cli_request_destructor(struct cli_request *req)
 105 {
 106         if (req->enc_state != NULL) {
 107                 common_free_enc_buffer(req->enc_state, req->outbuf);
 108         }
 109         DLIST_REMOVE(req->cli->outstanding_requests, req);
 110         return 0;
 111 }
 112
 113 /*
 114  * Create a fresh async smb request
 115  */
 116
 117 struct async_req *cli_request_new(TALLOC_CTX *mem_ctx,
 118                                   struct event_context *ev,
 119                                   struct cli_state *cli,
 120                                   uint8_t num_words, size_t num_bytes,
 121                                   struct cli_request **preq)
 122 {
 123         struct async_req *result;
 124         struct cli_request *cli_req;
 125         size_t bufsize = smb_size + num_words * 2 + num_bytes;
 126
 127         result = async_req_new(mem_ctx, ev);
 128         if (result == NULL) {
 129                 return NULL;
 130         }
 131
 132         cli_req = (struct cli_request *)talloc_size(
 133                 result, sizeof(*cli_req) + bufsize);
 134         if (cli_req == NULL) {
 135                 TALLOC_FREE(result);
 136                 return NULL;
 137         }
 138         talloc_set_name_const(cli_req, "struct cli_request");
 139         result->private_data = cli_req;
 140         result->print = cli_request_print;
 141
 142         cli_req->async = result;
 143         cli_req->cli = cli;
 144         cli_req->outbuf = ((char *)cli_req + sizeof(*cli_req));
 145         cli_req->sent = 0;
 146         cli_req->mid = cli_new_mid(cli);
 147         cli_req->inbuf = NULL;
 148         cli_req->enc_state = NULL;
 149
 150         SCVAL(cli_req->outbuf, smb_wct, num_words);
 151         SSVAL(cli_req->outbuf, smb_vwv + num_words * 2, num_bytes);
 152
 153         DLIST_ADD_END(cli->outstanding_requests, cli_req,
 154                       struct cli_request *);
 155         talloc_set_destructor(cli_req, cli_request_destructor);
 156
 157         DEBUG(10, ("cli_request_new: mid=%d\n", cli_req->mid));
 158
 159         *preq = cli_req;
 160         return result;
 161 }
 162
 163 /*
 164  * Convenience function to get the SMB part out of an async_req
 165  */
 166
 167 struct cli_request *cli_request_get(struct async_req *req)
 168 {
 169         if (req == NULL) {
 170                 return NULL;
 171         }
 172         return talloc_get_type_abort(req->private_data, struct cli_request);
 173 }
 174
 175 /*
 176  * A PDU has arrived on cli->evt_inbuf
 177  */
 178
 179 static void handle_incoming_pdu(struct cli_state *cli)
 180 {
 181         struct cli_request *req;
 182         uint16_t mid;
 183         size_t raw_pdu_len, buf_len, pdu_len, rest_len;
 184         char *pdu;
 185         NTSTATUS status;
 186
 187         /*
 188          * The encrypted PDU len might differ from the unencrypted one
 189          */
 190         raw_pdu_len = smb_len(cli->evt_inbuf) + 4;
 191         buf_len = talloc_get_size(cli->evt_inbuf);
 192         rest_len = buf_len - raw_pdu_len;
 193
 194         if (buf_len == raw_pdu_len) {
 195                 /*
 196                  * Optimal case: Exactly one PDU was in the socket buffer
 197                  */
 198                 pdu = cli->evt_inbuf;
 199                 cli->evt_inbuf = NULL;
 200         }
 201         else {
 202                 DEBUG(11, ("buf_len = %d, raw_pdu_len = %d, splitting "
 203                            "buffer\n", (int)buf_len, (int)raw_pdu_len));
 204
 205                 if (raw_pdu_len < rest_len) {
 206                         /*
 207                          * The PDU is shorter, talloc_memdup that one.
 208                          */
 209                         pdu = (char *)talloc_memdup(
 210                                 cli, cli->evt_inbuf, raw_pdu_len);
 211
 212                         memmove(cli->evt_inbuf, cli->evt_inbuf + raw_pdu_len,
 213                                 buf_len - raw_pdu_len);
 214
 215                         cli->evt_inbuf = TALLOC_REALLOC_ARRAY(
 216                                 NULL, cli->evt_inbuf, char, rest_len);
 217
 218                         if (pdu == NULL) {
 219                                 status = NT_STATUS_NO_MEMORY;
 220                                 goto invalidate_requests;
 221                         }
 222                 }
 223                 else {
 224                         /*
 225                          * The PDU is larger than the rest, talloc_memdup the
 226                          * rest
 227                          */
 228                         pdu = cli->evt_inbuf;
 229
 230                         cli->evt_inbuf = (char *)talloc_memdup(
 231                                 cli, pdu + raw_pdu_len, rest_len);
 232
 233                         if (cli->evt_inbuf == NULL) {
 234                                 status = NT_STATUS_NO_MEMORY;
 235                                 goto invalidate_requests;
 236                         }
 237                 }
 238
 239         }
 240
 241         /*
 242          * TODO: Handle oplock break requests
 243          */
 244
 245         if (cli_encryption_on(cli) && CVAL(pdu, 0) == 0) {
 246                 uint16_t enc_ctx_num;
 247
 248                 status = get_enc_ctx_num((uint8_t *)pdu, &enc_ctx_num);
 249                 if (!NT_STATUS_IS_OK(status)) {
 250                         DEBUG(10, ("get_enc_ctx_num returned %s\n",
 251                                    nt_errstr(status)));
 252                         goto invalidate_requests;
 253                 }
 254
 255                 if (enc_ctx_num != cli->trans_enc_state->enc_ctx_num) {
 256                         DEBUG(10, ("wrong enc_ctx %d, expected %d\n",
 257                                    enc_ctx_num,
 258                                    cli->trans_enc_state->enc_ctx_num));
 259                         status = NT_STATUS_INVALID_HANDLE;
 260                         goto invalidate_requests;
 261                 }
 262
 263                 status = common_decrypt_buffer(cli->trans_enc_state,
 264                                                pdu);
 265                 if (!NT_STATUS_IS_OK(status)) {
 266                         DEBUG(10, ("common_decrypt_buffer returned %s\n",
 267                                    nt_errstr(status)));
 268                         goto invalidate_requests;
 269                 }
 270         }
 271
 272         if (!cli_check_sign_mac(cli, pdu)) {
 273                 DEBUG(10, ("cli_check_sign_mac failed\n"));
 274                 status = NT_STATUS_ACCESS_DENIED;
 275                 goto invalidate_requests;
 276         }
 277
 278         mid = SVAL(pdu, smb_mid);
 279
 280         DEBUG(10, ("handle_incoming_pdu: got mid %d\n", mid));
 281
 282         for (req = cli->outstanding_requests; req; req = req->next) {
 283                 if (req->mid == mid) {
 284                         break;
 285                 }
 286         }
 287
 288         pdu_len = smb_len(pdu) + 4;
 289
 290         if (req == NULL) {
 291                 DEBUG(3, ("Request for mid %d not found, dumping PDU\n", mid));
 292
 293                 TALLOC_FREE(pdu);
 294                 return;
 295         }
 296
 297         req->inbuf = talloc_move(req, &pdu);
 298
 299         async_req_done(req->async);
 300         return;
 301
 302  invalidate_requests:
 303
 304         DEBUG(10, ("handle_incoming_pdu: Aborting with %s\n",
 305                    nt_errstr(status)));
 306
 307         for (req = cli->outstanding_requests; req; req = req->next) {
 308                 async_req_error(req->async, status);
 309         }
 310         return;
 311 }
 312
 313 /*
 314  * fd event callback. This is the basic connection to the socket
 315  */
 316
 317 static void cli_state_handler(struct event_context *event_ctx,
 318                               struct fd_event *event, uint16 flags, void *p)
 319 {
 320         struct cli_state *cli = (struct cli_state *)p;
 321         struct cli_request *req, *next;
 322         NTSTATUS status;
 323
 324         DEBUG(11, ("cli_state_handler called with flags %d\n", flags));
 325
 326         if (flags & EVENT_FD_READ) {
 327                 int res, available;
 328                 size_t old_size, new_size;
 329                 char *tmp;
 330
 331                 res = ioctl(cli->fd, FIONREAD, &available);
 332                 if (res == -1) {
 333                         DEBUG(10, ("ioctl(FIONREAD) failed: %s\n",
 334                                    strerror(errno)));
 335                         status = map_nt_error_from_unix(errno);
 336                         goto sock_error;
 337                 }
 338
 339                 if (available == 0) {
 340                         /* EOF */
 341                         status = NT_STATUS_END_OF_FILE;
 342                         goto sock_error;
 343                 }
 344
 345                 old_size = talloc_get_size(cli->evt_inbuf);
 346                 new_size = old_size + available;
 347
 348                 if (new_size < old_size) {
 349                         /* wrap */
 350                         status = NT_STATUS_UNEXPECTED_IO_ERROR;
 351                         goto sock_error;
 352                 }
 353
 354                 tmp = TALLOC_REALLOC_ARRAY(cli, cli->evt_inbuf, char,
 355                                            new_size);
 356                 if (tmp == NULL) {
 357                         /* nomem */
 358                         status = NT_STATUS_NO_MEMORY;
 359                         goto sock_error;
 360                 }
 361                 cli->evt_inbuf = tmp;
 362
 363                 res = sys_recv(cli->fd, cli->evt_inbuf + old_size, available, 0);
 364                 if (res == -1) {
 365                         DEBUG(10, ("recv failed: %s\n", strerror(errno)));
 366                         status = map_nt_error_from_unix(errno);
 367                         goto sock_error;
 368                 }
 369
 370                 DEBUG(11, ("cli_state_handler: received %d bytes, "
 371                            "smb_len(evt_inbuf) = %d\n", (int)res,
 372                            smb_len(cli->evt_inbuf)));
 373
 374                 /* recv *might* have returned less than announced */
 375                 new_size = old_size + res;
 376
 377                 /* shrink, so I don't expect errors here */
 378                 cli->evt_inbuf = TALLOC_REALLOC_ARRAY(cli, cli->evt_inbuf,
 379                                                       char, new_size);
 380
 381                 while ((cli->evt_inbuf != NULL)
 382                        && ((smb_len(cli->evt_inbuf) + 4) <= new_size)) {
 383                         /*
 384                          * we've got a complete NBT level PDU in evt_inbuf
 385                          */
 386                         handle_incoming_pdu(cli);
 387                         new_size = talloc_get_size(cli->evt_inbuf);
 388                 }
 389         }
 390
 391         if (flags & EVENT_FD_WRITE) {
 392                 size_t to_send;
 393                 ssize_t sent;
 394
 395                 for (req = cli->outstanding_requests; req; req = req->next) {
 396                         to_send = smb_len(req->outbuf)+4;
 397                         if (to_send > req->sent) {
 398                                 break;
 399                         }
 400                 }
 401
 402                 if (req == NULL) {
 403                         event_fd_set_not_writeable(event);
 404                         return;
 405                 }
 406
 407                 sent = sys_send(cli->fd, req->outbuf + req->sent,
 408                             to_send - req->sent, 0);
 409
 410                 if (sent < 0) {
 411                         status = map_nt_error_from_unix(errno);
 412                         goto sock_error;
 413                 }
 414
 415                 req->sent += sent;
 416
 417                 if (req->sent == to_send) {
 418                         return;
 419                 }
 420         }
 421         return;
 422
 423  sock_error:
 424         for (req = cli->outstanding_requests; req; req = next) {
 425                 next = req;
 426                 async_req_error(req->async, status);
 427         }
 428         TALLOC_FREE(cli->fd_event);
 429         close(cli->fd);
 430         cli->fd = -1;
 431 }
 432
 433 /*
 434  * Holder for a talloc_destructor, we need to zero out the pointers in cli
 435  * when deleting
 436  */
 437 struct cli_tmp_event {
 438         struct cli_state *cli;
 439 };
 440
 441 static int cli_tmp_event_destructor(struct cli_tmp_event *e)
 442 {
 443         TALLOC_FREE(e->cli->fd_event);
 444         TALLOC_FREE(e->cli->event_ctx);
 445         return 0;
 446 }
 447
 448 /*
 449  * Create a temporary event context for use in the sync helper functions
 450  */
 451
 452 struct cli_tmp_event *cli_tmp_event_ctx(TALLOC_CTX *mem_ctx,
 453                                         struct cli_state *cli)
 454 {
 455         struct cli_tmp_event *state;
 456
 457         if (cli->event_ctx != NULL) {
 458                 return NULL;
 459         }
 460
 461         state = talloc(mem_ctx, struct cli_tmp_event);
 462         if (state == NULL) {
 463                 return NULL;
 464         }
 465         state->cli = cli;
 466         talloc_set_destructor(state, cli_tmp_event_destructor);
 467
 468         cli->event_ctx = event_context_init(state);
 469         if (cli->event_ctx == NULL) {
 470                 TALLOC_FREE(state);
 471                 return NULL;
 472         }
 473
 474         cli->fd_event = event_add_fd(cli->event_ctx, state, cli->fd,
 475                                      EVENT_FD_READ, cli_state_handler, cli);
 476         if (cli->fd_event == NULL) {
 477                 TALLOC_FREE(state);
 478                 return NULL;
 479         }
 480         return state;
 481 }
 482
 483 /*
 484  * Attach an event context permanently to a cli_struct
 485  */
 486
 487 NTSTATUS cli_add_event_ctx(struct cli_state *cli,
 488                            struct event_context *event_ctx)
 489 {
 490         cli->event_ctx = event_ctx;
 491         cli->fd_event = event_add_fd(event_ctx, cli, cli->fd, EVENT_FD_READ,
 492                                      cli_state_handler, cli);
 493         if (cli->fd_event == NULL) {
 494                 return NT_STATUS_NO_MEMORY;
 495         }
 496         return NT_STATUS_OK;
 497 }