1 /* 2 * Copyright (C) 2008 Edwin Groothuis. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16 * ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE 17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23 * SUCH DAMAGE. 24 */ 25 26 #include <sys/cdefs.h> 27 __FBSDID("$FreeBSD$"); 28 29 #include <sys/socket.h> 30 #include <sys/types.h> 31 #include <sys/sysctl.h> 32 #include <sys/stat.h> 33 34 #include <netinet/in.h> 35 #include <arpa/tftp.h> 36 37 #include <ctype.h> 38 #include <stdio.h> 39 #include <stdlib.h> 40 #include <string.h> 41 #include <syslog.h> 42 43 #include "tftp-utils.h" 44 #include "tftp-io.h" 45 #include "tftp-options.h" 46 47 /* 48 * Option handlers 49 */ 50 51 struct options options[] = { 52 { "tsize", NULL, NULL, NULL /* option_tsize */, 1 }, 53 { "timeout", NULL, NULL, option_timeout, 1 }, 54 { "blksize", NULL, NULL, option_blksize, 1 }, 55 { "blksize2", NULL, NULL, option_blksize2, 0 }, 56 { "rollover", NULL, NULL, option_rollover, 0 }, 57 { NULL, NULL, NULL, NULL, 0 } 58 }; 59 60 /* By default allow them */ 61 int options_rfc_enabled = 1; 62 int options_extra_enabled = 1; 63 64 /* 65 * Rules for the option handlers: 66 * - If there is no o_request, there will be no processing. 67 * 68 * For servers 69 * - Logging is done as warnings. 70 * - The handler exit()s if there is a serious problem with the 71 * values submitted in the option. 72 * 73 * For clients 74 * - Logging is done as errors. After all, the server shouldn't 75 * return rubbish. 76 * - The handler returns if there is a serious problem with the 77 * values submitted in the option. 78 * - Sending the EBADOP packets is done by the handler. 79 */ 80 81 int 82 option_tsize(int peer, struct tftphdr *tp, int mode, struct stat *stbuf) 83 { 84 85 if (options[OPT_TSIZE].o_request == NULL) 86 return (0); 87 88 if (mode == RRQ) 89 asprintf(&options[OPT_TSIZE].o_reply, 90 "%ju", stbuf->st_size); 91 else 92 /* XXX Allows writes of all sizes. */ 93 options[OPT_TSIZE].o_reply = 94 strdup(options[OPT_TSIZE].o_request); 95 return (0); 96 } 97 98 int 99 option_timeout(int peer) 100 { 101 102 if (options[OPT_TIMEOUT].o_request == NULL) 103 return (0); 104 105 int to = atoi(options[OPT_TIMEOUT].o_request); 106 if (to < TIMEOUT_MIN || to > TIMEOUT_MAX) { 107 tftp_log(acting_as_client ? LOG_ERR : LOG_WARNING, 108 "Received bad value for timeout. " 109 "Should be between %d and %d, received %s", 110 TIMEOUT_MIN, TIMEOUT_MAX); 111 send_error(peer, EBADOP); 112 if (acting_as_client) 113 return (1); 114 exit(1); 115 } else { 116 timeoutpacket = to; 117 options[OPT_TIMEOUT].o_reply = 118 strdup(options[OPT_TIMEOUT].o_request); 119 } 120 settimeouts(timeoutpacket, timeoutnetwork, maxtimeouts); 121 122 if (debug&DEBUG_OPTIONS) 123 tftp_log(LOG_DEBUG, "Setting timeout to '%s'", 124 options[OPT_TIMEOUT].o_reply); 125 126 return (0); 127 } 128 129 int 130 option_rollover(int peer) 131 { 132 133 if (options[OPT_ROLLOVER].o_request == NULL) 134 return (0); 135 136 if (strcmp(options[OPT_ROLLOVER].o_request, "0") != 0 137 && strcmp(options[OPT_ROLLOVER].o_request, "1") != 0) { 138 tftp_log(acting_as_client ? LOG_ERR : LOG_WARNING, 139 "Bad value for rollover, " 140 "should be either 0 or 1, received '%s', " 141 "ignoring request", 142 options[OPT_ROLLOVER].o_request); 143 if (acting_as_client) { 144 send_error(peer, EBADOP); 145 return (1); 146 } 147 return (0); 148 } 149 options[OPT_ROLLOVER].o_reply = 150 strdup(options[OPT_ROLLOVER].o_request); 151 152 if (debug&DEBUG_OPTIONS) 153 tftp_log(LOG_DEBUG, "Setting rollover to '%s'", 154 options[OPT_ROLLOVER].o_reply); 155 156 return (0); 157 } 158 159 int 160 option_blksize(int peer) 161 { 162 int *maxdgram; 163 char maxbuffer[100]; 164 size_t len; 165 166 if (options[OPT_BLKSIZE].o_request == NULL) 167 return (0); 168 169 /* maximum size of an UDP packet according to the system */ 170 len = sizeof(maxbuffer); 171 if (sysctlbyname("net.inet.udp.maxdgram", 172 maxbuffer, &len, NULL, 0) < 0) { 173 tftp_log(LOG_ERR, "sysctl: net.inet.udp.maxdgram"); 174 return (acting_as_client ? 1 : 0); 175 } 176 maxdgram = (int *)maxbuffer; 177 178 int size = atoi(options[OPT_BLKSIZE].o_request); 179 if (size < BLKSIZE_MIN || size > BLKSIZE_MAX) { 180 if (acting_as_client) { 181 tftp_log(LOG_ERR, 182 "Invalid blocksize (%d bytes), aborting", 183 size); 184 send_error(peer, EBADOP); 185 return (1); 186 } else { 187 tftp_log(LOG_WARNING, 188 "Invalid blocksize (%d bytes), ignoring request", 189 size); 190 return (0); 191 } 192 } 193 194 if (size > *maxdgram) { 195 if (acting_as_client) { 196 tftp_log(LOG_ERR, 197 "Invalid blocksize (%d bytes), " 198 "net.inet.udp.maxdgram sysctl limits it to " 199 "%d bytes.\n", size, *maxdgram); 200 send_error(peer, EBADOP); 201 return (1); 202 } else { 203 tftp_log(LOG_WARNING, 204 "Invalid blocksize (%d bytes), " 205 "net.inet.udp.maxdgram sysctl limits it to " 206 "%d bytes.\n", size, *maxdgram); 207 size = *maxdgram; 208 /* No reason to return */ 209 } 210 } 211 212 asprintf(&options[OPT_BLKSIZE].o_reply, "%d", size); 213 segsize = size; 214 pktsize = size + 4; 215 if (debug&DEBUG_OPTIONS) 216 tftp_log(LOG_DEBUG, "Setting blksize to '%s'", 217 options[OPT_BLKSIZE].o_reply); 218 219 return (0); 220 } 221 222 int 223 option_blksize2(int peer) 224 { 225 int *maxdgram; 226 char maxbuffer[100]; 227 int size, i; 228 size_t len; 229 230 int sizes[] = { 231 8, 16, 32, 64, 128, 256, 512, 1024, 232 2048, 4096, 8192, 16384, 32768, 0 233 }; 234 235 if (options[OPT_BLKSIZE2].o_request == NULL) 236 return (0); 237 238 /* maximum size of an UDP packet according to the system */ 239 len = sizeof(maxbuffer); 240 if (sysctlbyname("net.inet.udp.maxdgram", 241 maxbuffer, &len, NULL, 0) < 0) { 242 tftp_log(LOG_ERR, "sysctl: net.inet.udp.maxdgram"); 243 return (acting_as_client ? 1 : 0); 244 } 245 maxdgram = (int *)maxbuffer; 246 247 size = atoi(options[OPT_BLKSIZE2].o_request); 248 for (i = 0; sizes[i] != 0; i++) { 249 if (size == sizes[i]) break; 250 } 251 if (sizes[i] == 0) { 252 tftp_log(LOG_INFO, 253 "Invalid blocksize2 (%d bytes), ignoring request", size); 254 return (acting_as_client ? 1 : 0); 255 } 256 257 if (size > *maxdgram) { 258 for (i = 0; sizes[i+1] != 0; i++) { 259 if (*maxdgram < sizes[i+1]) break; 260 } 261 tftp_log(LOG_INFO, 262 "Invalid blocksize2 (%d bytes), net.inet.udp.maxdgram " 263 "sysctl limits it to %d bytes.\n", size, *maxdgram); 264 size = sizes[i]; 265 /* No need to return */ 266 } 267 268 asprintf(&options[OPT_BLKSIZE2].o_reply, "%d", size); 269 segsize = size; 270 pktsize = size + 4; 271 if (debug&DEBUG_OPTIONS) 272 tftp_log(LOG_DEBUG, "Setting blksize2 to '%s'", 273 options[OPT_BLKSIZE2].o_reply); 274 275 return (0); 276 } 277 278 /* 279 * Append the available options to the header 280 */ 281 uint16_t 282 make_options(int peer, char *buffer, uint16_t size) { 283 int i; 284 char *value; 285 const char *option; 286 uint16_t length; 287 uint16_t returnsize = 0; 288 289 if (!options_rfc_enabled) return (0); 290 291 for (i = 0; options[i].o_type != NULL; i++) { 292 if (options[i].rfc == 0 && !options_extra_enabled) 293 continue; 294 295 option = options[i].o_type; 296 if (acting_as_client) 297 value = options[i].o_request; 298 else 299 value = options[i].o_reply; 300 if (value == NULL) 301 continue; 302 303 length = strlen(value) + strlen(option) + 2; 304 if (size <= length) { 305 tftp_log(LOG_ERR, 306 "Running out of option space for " 307 "option '%s' with value '%s': " 308 "needed %d bytes, got %d bytes", 309 option, value, size, length); 310 continue; 311 } 312 313 sprintf(buffer, "%s%c%s%c", option, '\000', value, '\000'); 314 size -= length; 315 buffer += length; 316 returnsize += length; 317 } 318 319 return (returnsize); 320 } 321 322 /* 323 * Parse the received options in the header 324 */ 325 int 326 parse_options(int peer, char *buffer, uint16_t size) 327 { 328 int i, options_failed; 329 char *c, *cp, *option, *value; 330 331 if (!options_rfc_enabled) return (0); 332 333 /* Parse the options */ 334 cp = buffer; 335 options_failed = 0; 336 while (size > 0) { 337 option = cp; 338 i = get_field(peer, cp, size); 339 cp += i; 340 341 value = cp; 342 i = get_field(peer, cp, size); 343 cp += i; 344 345 /* We are at the end */ 346 if (*option == '\0') break; 347 348 if (debug&DEBUG_OPTIONS) 349 tftp_log(LOG_DEBUG, 350 "option: '%s' value: '%s'", option, value); 351 352 for (c = option; *c; c++) 353 if (isupper(*c)) 354 *c = tolower(*c); 355 for (i = 0; options[i].o_type != NULL; i++) { 356 if (strcmp(option, options[i].o_type) == 0) { 357 if (!acting_as_client) 358 options[i].o_request = value; 359 if (!options_extra_enabled && !options[i].rfc) { 360 tftp_log(LOG_INFO, 361 "Option '%s' with value '%s' found " 362 "but it is not an RFC option", 363 option, value); 364 continue; 365 } 366 if (options[i].o_handler) 367 options_failed += 368 (options[i].o_handler)(peer); 369 break; 370 } 371 } 372 if (options[i].o_type == NULL) 373 tftp_log(LOG_WARNING, 374 "Unknown option: '%s'", option); 375 376 size -= strlen(option) + strlen(value) + 2; 377 } 378 379 return (options_failed); 380 } 381 382 /* 383 * Set some default values in the options 384 */ 385 void 386 init_options(void) 387 { 388 389 options[OPT_ROLLOVER].o_request = strdup("0"); 390 } 391