1 /* This source code was modified by Martin Hedenfalk <mhe (at) stacken.kth.se> for 2 * use in Curl. His latest changes were done 2000-09-18. 3 * 4 * It has since been patched and modified a lot by Daniel Stenberg 5 * <daniel (at) haxx.se> to make it better applied to curl conditions, and to make 6 * it not use globals, pollute name space and more. This source code awaits a 7 * rewrite to work around the paragraph 2 in the BSD licenses as explained 8 * below. 9 * 10 * Copyright (c) 1998, 1999, 2017 Kungliga Tekniska Hgskolan 11 * (Royal Institute of Technology, Stockholm, Sweden). 12 * 13 * Copyright (C) 2001 - 2019, Daniel Stenberg, <daniel (at) haxx.se>, et al. 14 * 15 * All rights reserved. 16 * 17 * Redistribution and use in source and binary forms, with or without 18 * modification, are permitted provided that the following conditions 19 * are met: 20 * 21 * 1. Redistributions of source code must retain the above copyright 22 * notice, this list of conditions and the following disclaimer. 23 * 24 * 2. Redistributions in binary form must reproduce the above copyright 25 * notice, this list of conditions and the following disclaimer in the 26 * documentation and/or other materials provided with the distribution. 27 * 28 * 3. Neither the name of the Institute nor the names of its contributors 29 * may be used to endorse or promote products derived from this software 30 * without specific prior written permission. 31 * 32 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND 33 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 34 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 35 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE 36 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 37 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 38 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 39 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 40 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 41 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 42 * SUCH DAMAGE. */ 43 44 #include "curl_setup.h" 45 46 #ifndef CURL_DISABLE_FTP 47 #ifdef HAVE_GSSAPI 48 49 #ifdef HAVE_NETDB_H 50 #include <netdb.h> 51 #endif 52 53 #include <limits.h> 54 55 #include "urldata.h" 56 #include "curl_base64.h" 57 #include "curl_memory.h" 58 #include "curl_sec.h" 59 #include "ftp.h" 60 #include "sendf.h" 61 #include "strcase.h" 62 #include "warnless.h" 63 #include "strdup.h" 64 /* The last 3 #include files should be in this order */ 65 #include "curl_printf.h" 66 #include "curl_memory.h" 67 #include "memdebug.h" 68 69 static const struct { 70 enum protection_level level; 71 const char *name; 72 } level_names[] = { 73 { PROT_CLEAR, "clear" }, 74 { PROT_SAFE, "safe" }, 75 { PROT_CONFIDENTIAL, "confidential" }, 76 { PROT_PRIVATE, "private" } 77 }; 78 79 static enum protection_level 80 name_to_level(const char *name) 81 { 82 int i; 83 for(i = 0; i < (int)sizeof(level_names)/(int)sizeof(level_names[0]); i++) 84 if(checkprefix(name, level_names[i].name)) 85 return level_names[i].level; 86 return PROT_NONE; 87 } 88 89 /* Convert a protocol |level| to its char representation. 90 We take an int to catch programming mistakes. */ 91 static char level_to_char(int level) 92 { 93 switch(level) { 94 case PROT_CLEAR: 95 return 'C'; 96 case PROT_SAFE: 97 return 'S'; 98 case PROT_CONFIDENTIAL: 99 return 'E'; 100 case PROT_PRIVATE: 101 return 'P'; 102 case PROT_CMD: 103 /* Fall through */ 104 default: 105 /* Those 2 cases should not be reached! */ 106 break; 107 } 108 DEBUGASSERT(0); 109 /* Default to the most secure alternative. */ 110 return 'P'; 111 } 112 113 /* Send an FTP command defined by |message| and the optional arguments. The 114 function returns the ftp_code. If an error occurs, -1 is returned. */ 115 static int ftp_send_command(struct connectdata *conn, const char *message, ...) 116 { 117 int ftp_code; 118 ssize_t nread = 0; 119 va_list args; 120 char print_buffer[50]; 121 122 va_start(args, message); 123 mvsnprintf(print_buffer, sizeof(print_buffer), message, args); 124 va_end(args); 125 126 if(Curl_ftpsend(conn, print_buffer)) { 127 ftp_code = -1; 128 } 129 else { 130 if(Curl_GetFTPResponse(&nread, conn, &ftp_code)) 131 ftp_code = -1; 132 } 133 134 (void)nread; /* Unused */ 135 return ftp_code; 136 } 137 138 /* Read |len| from the socket |fd| and store it in |to|. Return a CURLcode 139 saying whether an error occurred or CURLE_OK if |len| was read. */ 140 static CURLcode 141 socket_read(curl_socket_t fd, void *to, size_t len) 142 { 143 char *to_p = to; 144 CURLcode result; 145 ssize_t nread = 0; 146 147 while(len > 0) { 148 result = Curl_read_plain(fd, to_p, len, &nread); 149 if(!result) { 150 len -= nread; 151 to_p += nread; 152 } 153 else { 154 /* FIXME: We are doing a busy wait */ 155 if(result == CURLE_AGAIN) 156 continue; 157 return result; 158 } 159 } 160 return CURLE_OK; 161 } 162 163 164 /* Write |len| bytes from the buffer |to| to the socket |fd|. Return a 165 CURLcode saying whether an error occurred or CURLE_OK if |len| was 166 written. */ 167 static CURLcode 168 socket_write(struct connectdata *conn, curl_socket_t fd, const void *to, 169 size_t len) 170 { 171 const char *to_p = to; 172 CURLcode result; 173 ssize_t written; 174 175 while(len > 0) { 176 result = Curl_write_plain(conn, fd, to_p, len, &written); 177 if(!result) { 178 len -= written; 179 to_p += written; 180 } 181 else { 182 /* FIXME: We are doing a busy wait */ 183 if(result == CURLE_AGAIN) 184 continue; 185 return result; 186 } 187 } 188 return CURLE_OK; 189 } 190 191 static CURLcode read_data(struct connectdata *conn, 192 curl_socket_t fd, 193 struct krb5buffer *buf) 194 { 195 int len; 196 void *tmp = NULL; 197 CURLcode result; 198 199 result = socket_read(fd, &len, sizeof(len)); 200 if(result) 201 return result; 202 203 if(len) { 204 /* only realloc if there was a length */ 205 len = ntohl(len); 206 tmp = Curl_saferealloc(buf->data, len); 207 } 208 if(tmp == NULL) 209 return CURLE_OUT_OF_MEMORY; 210 211 buf->data = tmp; 212 result = socket_read(fd, buf->data, len); 213 if(result) 214 return result; 215 buf->size = conn->mech->decode(conn->app_data, buf->data, len, 216 conn->data_prot, conn); 217 buf->index = 0; 218 return CURLE_OK; 219 } 220 221 static size_t 222 buffer_read(struct krb5buffer *buf, void *data, size_t len) 223 { 224 if(buf->size - buf->index < len) 225 len = buf->size - buf->index; 226 memcpy(data, (char *)buf->data + buf->index, len); 227 buf->index += len; 228 return len; 229 } 230 231 /* Matches Curl_recv signature */ 232 static ssize_t sec_recv(struct connectdata *conn, int sockindex, 233 char *buffer, size_t len, CURLcode *err) 234 { 235 size_t bytes_read; 236 size_t total_read = 0; 237 curl_socket_t fd = conn->sock[sockindex]; 238 239 *err = CURLE_OK; 240 241 /* Handle clear text response. */ 242 if(conn->sec_complete == 0 || conn->data_prot == PROT_CLEAR) 243 return read(fd, buffer, len); 244 245 if(conn->in_buffer.eof_flag) { 246 conn->in_buffer.eof_flag = 0; 247 return 0; 248 } 249 250 bytes_read = buffer_read(&conn->in_buffer, buffer, len); 251 len -= bytes_read; 252 total_read += bytes_read; 253 buffer += bytes_read; 254 255 while(len > 0) { 256 if(read_data(conn, fd, &conn->in_buffer)) 257 return -1; 258 if(conn->in_buffer.size == 0) { 259 if(bytes_read > 0) 260 conn->in_buffer.eof_flag = 1; 261 return bytes_read; 262 } 263 bytes_read = buffer_read(&conn->in_buffer, buffer, len); 264 len -= bytes_read; 265 total_read += bytes_read; 266 buffer += bytes_read; 267 } 268 /* FIXME: Check for overflow */ 269 return total_read; 270 } 271 272 /* Send |length| bytes from |from| to the |fd| socket taking care of encoding 273 and negociating with the server. |from| can be NULL. */ 274 /* FIXME: We don't check for errors nor report any! */ 275 static void do_sec_send(struct connectdata *conn, curl_socket_t fd, 276 const char *from, int length) 277 { 278 int bytes, htonl_bytes; /* 32-bit integers for htonl */ 279 char *buffer = NULL; 280 char *cmd_buffer; 281 size_t cmd_size = 0; 282 CURLcode error; 283 enum protection_level prot_level = conn->data_prot; 284 bool iscmd = (prot_level == PROT_CMD)?TRUE:FALSE; 285 286 DEBUGASSERT(prot_level > PROT_NONE && prot_level < PROT_LAST); 287 288 if(iscmd) { 289 if(!strncmp(from, "PASS ", 5) || !strncmp(from, "ACCT ", 5)) 290 prot_level = PROT_PRIVATE; 291 else 292 prot_level = conn->command_prot; 293 } 294 bytes = conn->mech->encode(conn->app_data, from, length, prot_level, 295 (void **)&buffer); 296 if(!buffer || bytes <= 0) 297 return; /* error */ 298 299 if(iscmd) { 300 error = Curl_base64_encode(conn->data, buffer, curlx_sitouz(bytes), 301 &cmd_buffer, &cmd_size); 302 if(error) { 303 free(buffer); 304 return; /* error */ 305 } 306 if(cmd_size > 0) { 307 static const char *enc = "ENC "; 308 static const char *mic = "MIC "; 309 if(prot_level == PROT_PRIVATE) 310 socket_write(conn, fd, enc, 4); 311 else 312 socket_write(conn, fd, mic, 4); 313 314 socket_write(conn, fd, cmd_buffer, cmd_size); 315 socket_write(conn, fd, "\r\n", 2); 316 infof(conn->data, "Send: %s%s\n", prot_level == PROT_PRIVATE?enc:mic, 317 cmd_buffer); 318 free(cmd_buffer); 319 } 320 } 321 else { 322 htonl_bytes = htonl(bytes); 323 socket_write(conn, fd, &htonl_bytes, sizeof(htonl_bytes)); 324 socket_write(conn, fd, buffer, curlx_sitouz(bytes)); 325 } 326 free(buffer); 327 } 328 329 static ssize_t sec_write(struct connectdata *conn, curl_socket_t fd, 330 const char *buffer, size_t length) 331 { 332 ssize_t tx = 0, len = conn->buffer_size; 333 334 len -= conn->mech->overhead(conn->app_data, conn->data_prot, 335 curlx_sztosi(len)); 336 if(len <= 0) 337 len = length; 338 while(length) { 339 if(length < (size_t)len) 340 len = length; 341 342 do_sec_send(conn, fd, buffer, curlx_sztosi(len)); 343 length -= len; 344 buffer += len; 345 tx += len; 346 } 347 return tx; 348 } 349 350 /* Matches Curl_send signature */ 351 static ssize_t sec_send(struct connectdata *conn, int sockindex, 352 const void *buffer, size_t len, CURLcode *err) 353 { 354 curl_socket_t fd = conn->sock[sockindex]; 355 *err = CURLE_OK; 356 return sec_write(conn, fd, buffer, len); 357 } 358 359 int Curl_sec_read_msg(struct connectdata *conn, char *buffer, 360 enum protection_level level) 361 { 362 /* decoded_len should be size_t or ssize_t but conn->mech->decode returns an 363 int */ 364 int decoded_len; 365 char *buf; 366 int ret_code = 0; 367 size_t decoded_sz = 0; 368 CURLcode error; 369 370 if(!conn->mech) 371 /* not inititalized, return error */ 372 return -1; 373 374 DEBUGASSERT(level > PROT_NONE && level < PROT_LAST); 375 376 error = Curl_base64_decode(buffer + 4, (unsigned char **)&buf, &decoded_sz); 377 if(error || decoded_sz == 0) 378 return -1; 379 380 if(decoded_sz > (size_t)INT_MAX) { 381 free(buf); 382 return -1; 383 } 384 decoded_len = curlx_uztosi(decoded_sz); 385 386 decoded_len = conn->mech->decode(conn->app_data, buf, decoded_len, 387 level, conn); 388 if(decoded_len <= 0) { 389 free(buf); 390 return -1; 391 } 392 393 if(conn->data->set.verbose) { 394 buf[decoded_len] = '\n'; 395 Curl_debug(conn->data, CURLINFO_HEADER_IN, buf, decoded_len + 1); 396 } 397 398 buf[decoded_len] = '\0'; 399 if(decoded_len <= 3) 400 /* suspiciously short */ 401 return 0; 402 403 if(buf[3] != '-') 404 /* safe to ignore return code */ 405 (void)sscanf(buf, "%d", &ret_code); 406 407 if(buf[decoded_len - 1] == '\n') 408 buf[decoded_len - 1] = '\0'; 409 /* FIXME: Is |buffer| length always greater than |decoded_len|? */ 410 strcpy(buffer, buf); 411 free(buf); 412 return ret_code; 413 } 414 415 /* FIXME: The error code returned here is never checked. */ 416 static int sec_set_protection_level(struct connectdata *conn) 417 { 418 int code; 419 char *pbsz; 420 static unsigned int buffer_size = 1 << 20; /* 1048576 */ 421 enum protection_level level = conn->request_data_prot; 422 423 DEBUGASSERT(level > PROT_NONE && level < PROT_LAST); 424 425 if(!conn->sec_complete) { 426 infof(conn->data, "Trying to change the protection level after the" 427 " completion of the data exchange.\n"); 428 return -1; 429 } 430 431 /* Bail out if we try to set up the same level */ 432 if(conn->data_prot == level) 433 return 0; 434 435 if(level) { 436 code = ftp_send_command(conn, "PBSZ %u", buffer_size); 437 if(code < 0) 438 return -1; 439 440 if(code/100 != 2) { 441 failf(conn->data, "Failed to set the protection's buffer size."); 442 return -1; 443 } 444 conn->buffer_size = buffer_size; 445 446 pbsz = strstr(conn->data->state.buffer, "PBSZ="); 447 if(pbsz) { 448 /* ignore return code, use default value if it fails */ 449 (void)sscanf(pbsz, "PBSZ=%u", &buffer_size); 450 if(buffer_size < conn->buffer_size) 451 conn->buffer_size = buffer_size; 452 } 453 } 454 455 /* Now try to negiociate the protection level. */ 456 code = ftp_send_command(conn, "PROT %c", level_to_char(level)); 457 458 if(code < 0) 459 return -1; 460 461 if(code/100 != 2) { 462 failf(conn->data, "Failed to set the protection level."); 463 return -1; 464 } 465 466 conn->data_prot = level; 467 if(level == PROT_PRIVATE) 468 conn->command_prot = level; 469 470 return 0; 471 } 472 473 int 474 Curl_sec_request_prot(struct connectdata *conn, const char *level) 475 { 476 enum protection_level l = name_to_level(level); 477 if(l == PROT_NONE) 478 return -1; 479 DEBUGASSERT(l > PROT_NONE && l < PROT_LAST); 480 conn->request_data_prot = l; 481 return 0; 482 } 483 484 static CURLcode choose_mech(struct connectdata *conn) 485 { 486 int ret; 487 struct Curl_easy *data = conn->data; 488 void *tmp_allocation; 489 const struct Curl_sec_client_mech *mech = &Curl_krb5_client_mech; 490 491 tmp_allocation = realloc(conn->app_data, mech->size); 492 if(tmp_allocation == NULL) { 493 failf(data, "Failed realloc of size %zu", mech->size); 494 mech = NULL; 495 return CURLE_OUT_OF_MEMORY; 496 } 497 conn->app_data = tmp_allocation; 498 499 if(mech->init) { 500 ret = mech->init(conn->app_data); 501 if(ret) { 502 infof(data, "Failed initialization for %s. Skipping it.\n", 503 mech->name); 504 return CURLE_FAILED_INIT; 505 } 506 } 507 508 infof(data, "Trying mechanism %s...\n", mech->name); 509 ret = ftp_send_command(conn, "AUTH %s", mech->name); 510 if(ret < 0) 511 /* FIXME: This error is too generic but it is OK for now. */ 512 return CURLE_COULDNT_CONNECT; 513 514 if(ret/100 != 3) { 515 switch(ret) { 516 case 504: 517 infof(data, "Mechanism %s is not supported by the server (server " 518 "returned ftp code: 504).\n", mech->name); 519 break; 520 case 534: 521 infof(data, "Mechanism %s was rejected by the server (server returned " 522 "ftp code: 534).\n", mech->name); 523 break; 524 default: 525 if(ret/100 == 5) { 526 infof(data, "server does not support the security extensions\n"); 527 return CURLE_USE_SSL_FAILED; 528 } 529 break; 530 } 531 return CURLE_LOGIN_DENIED; 532 } 533 534 /* Authenticate */ 535 ret = mech->auth(conn->app_data, conn); 536 537 if(ret != AUTH_CONTINUE) { 538 if(ret != AUTH_OK) { 539 /* Mechanism has dumped the error to stderr, don't error here. */ 540 return -1; 541 } 542 DEBUGASSERT(ret == AUTH_OK); 543 544 conn->mech = mech; 545 conn->sec_complete = 1; 546 conn->recv[FIRSTSOCKET] = sec_recv; 547 conn->send[FIRSTSOCKET] = sec_send; 548 conn->recv[SECONDARYSOCKET] = sec_recv; 549 conn->send[SECONDARYSOCKET] = sec_send; 550 conn->command_prot = PROT_SAFE; 551 /* Set the requested protection level */ 552 /* BLOCKING */ 553 (void)sec_set_protection_level(conn); 554 } 555 556 return CURLE_OK; 557 } 558 559 CURLcode 560 Curl_sec_login(struct connectdata *conn) 561 { 562 return choose_mech(conn); 563 } 564 565 566 void 567 Curl_sec_end(struct connectdata *conn) 568 { 569 if(conn->mech != NULL && conn->mech->end) 570 conn->mech->end(conn->app_data); 571 free(conn->app_data); 572 conn->app_data = NULL; 573 if(conn->in_buffer.data) { 574 free(conn->in_buffer.data); 575 conn->in_buffer.data = NULL; 576 conn->in_buffer.size = 0; 577 conn->in_buffer.index = 0; 578 /* FIXME: Is this really needed? */ 579 conn->in_buffer.eof_flag = 0; 580 } 581 conn->sec_complete = 0; 582 conn->data_prot = PROT_CLEAR; 583 conn->mech = NULL; 584 } 585 586 #endif /* HAVE_GSSAPI */ 587 588 #endif /* CURL_DISABLE_FTP */ 589
