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