diff options
Diffstat (limited to 'libexec/tftpd/tftp-options.c')
| -rw-r--r-- | libexec/tftpd/tftp-options.c | 477 |
1 files changed, 477 insertions, 0 deletions
diff --git a/libexec/tftpd/tftp-options.c b/libexec/tftpd/tftp-options.c new file mode 100644 index 000000000000..7a261ac3d7c3 --- /dev/null +++ b/libexec/tftpd/tftp-options.c @@ -0,0 +1,477 @@ +/*- + * SPDX-License-Identifier: BSD-2-Clause + * + * Copyright (C) 2008 Edwin Groothuis. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include <sys/types.h> +#include <sys/socket.h> +#include <sys/stat.h> +#include <sys/sysctl.h> + +#include <netinet/in.h> +#include <arpa/tftp.h> + +#include <ctype.h> +#include <stdarg.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <syslog.h> + +#include "tftp-utils.h" +#include "tftp-io.h" +#include "tftp-options.h" + +/* + * Option handlers + */ + +struct options options[] = { + { "tsize", NULL, NULL, NULL /* option_tsize */, 1 }, + { "timeout", NULL, NULL, option_timeout, 1 }, + { "blksize", NULL, NULL, option_blksize, 1 }, + { "blksize2", NULL, NULL, option_blksize2, 0 }, + { "rollover", NULL, NULL, option_rollover, 0 }, + { "windowsize", NULL, NULL, option_windowsize, 1 }, + { NULL, NULL, NULL, NULL, 0 } +}; + +/* By default allow them */ +int options_rfc_enabled = 1; +int options_extra_enabled = 1; + +int +options_set_request(enum opt_enum opt, const char *fmt, ...) +{ + va_list ap; + char *str; + int ret; + + if (fmt == NULL) { + str = NULL; + } else { + va_start(ap, fmt); + ret = vasprintf(&str, fmt, ap); + va_end(ap); + if (ret < 0) + return (ret); + } + if (options[opt].o_request != NULL && + options[opt].o_request != options[opt].o_reply) + free(options[opt].o_request); + options[opt].o_request = str; + return (0); +} + +int +options_set_reply(enum opt_enum opt, const char *fmt, ...) +{ + va_list ap; + char *str; + int ret; + + if (fmt == NULL) { + str = NULL; + } else { + va_start(ap, fmt); + ret = vasprintf(&str, fmt, ap); + va_end(ap); + if (ret < 0) + return (ret); + } + if (options[opt].o_reply != NULL && + options[opt].o_reply != options[opt].o_request) + free(options[opt].o_reply); + options[opt].o_reply = str; + return (0); +} + +static void +options_set_reply_equal_request(enum opt_enum opt) +{ + + if (options[opt].o_reply != NULL && + options[opt].o_reply != options[opt].o_request) + free(options[opt].o_reply); + options[opt].o_reply = options[opt].o_request; +} + +/* + * Rules for the option handlers: + * - If there is no o_request, there will be no processing. + * + * For servers + * - Logging is done as warnings. + * - The handler exit()s if there is a serious problem with the + * values submitted in the option. + * + * For clients + * - Logging is done as errors. After all, the server shouldn't + * return rubbish. + * - The handler returns if there is a serious problem with the + * values submitted in the option. + * - Sending the EBADOP packets is done by the handler. + */ + +int +option_tsize(int peer __unused, struct tftphdr *tp __unused, int mode, + struct stat *stbuf) +{ + + if (options[OPT_TSIZE].o_request == NULL) + return (0); + + if (mode == RRQ) + options_set_reply(OPT_TSIZE, "%ju", (uintmax_t)stbuf->st_size); + else + /* XXX Allows writes of all sizes. */ + options_set_reply_equal_request(OPT_TSIZE); + return (0); +} + +int +option_timeout(int peer) +{ + int to; + + if (options[OPT_TIMEOUT].o_request == NULL) + return (0); + + to = atoi(options[OPT_TIMEOUT].o_request); + if (to < TIMEOUT_MIN || to > TIMEOUT_MAX) { + tftp_log(acting_as_client ? LOG_ERR : LOG_WARNING, + "Received bad value for timeout. " + "Should be between %d and %d, received %d", + TIMEOUT_MIN, TIMEOUT_MAX, to); + send_error(peer, EBADOP); + if (acting_as_client) + return (1); + exit(1); + } else { + timeoutpacket = to; + options_set_reply_equal_request(OPT_TIMEOUT); + } + settimeouts(timeoutpacket, timeoutnetwork, maxtimeouts); + + if (debug & DEBUG_OPTIONS) + tftp_log(LOG_DEBUG, "Setting timeout to '%s'", + options[OPT_TIMEOUT].o_reply); + + return (0); +} + +int +option_rollover(int peer) +{ + + if (options[OPT_ROLLOVER].o_request == NULL) + return (0); + + if (strcmp(options[OPT_ROLLOVER].o_request, "0") != 0 + && strcmp(options[OPT_ROLLOVER].o_request, "1") != 0) { + tftp_log(acting_as_client ? LOG_ERR : LOG_WARNING, + "Bad value for rollover, " + "should be either 0 or 1, received '%s', " + "ignoring request", + options[OPT_ROLLOVER].o_request); + if (acting_as_client) { + send_error(peer, EBADOP); + return (1); + } + return (0); + } + options_set_reply_equal_request(OPT_ROLLOVER); + + if (debug & DEBUG_OPTIONS) + tftp_log(LOG_DEBUG, "Setting rollover to '%s'", + options[OPT_ROLLOVER].o_reply); + + return (0); +} + +int +option_blksize(int peer) +{ + u_long maxdgram; + size_t len; + + if (options[OPT_BLKSIZE].o_request == NULL) + return (0); + + /* maximum size of an UDP packet according to the system */ + len = sizeof(maxdgram); + if (sysctlbyname("net.inet.udp.maxdgram", + &maxdgram, &len, NULL, 0) < 0) { + tftp_log(LOG_ERR, "sysctl: net.inet.udp.maxdgram"); + return (acting_as_client ? 1 : 0); + } + maxdgram -= 4; /* leave room for header */ + + int size = atoi(options[OPT_BLKSIZE].o_request); + if (size < BLKSIZE_MIN || size > BLKSIZE_MAX) { + if (acting_as_client) { + tftp_log(LOG_ERR, + "Invalid blocksize (%d bytes), aborting", + size); + send_error(peer, EBADOP); + return (1); + } else { + tftp_log(LOG_WARNING, + "Invalid blocksize (%d bytes), ignoring request", + size); + return (0); + } + } + + if (size > (int)maxdgram) { + if (acting_as_client) { + tftp_log(LOG_ERR, + "Invalid blocksize (%d bytes), " + "net.inet.udp.maxdgram sysctl limits it to " + "%ld bytes.\n", size, maxdgram); + send_error(peer, EBADOP); + return (1); + } else { + tftp_log(LOG_WARNING, + "Invalid blocksize (%d bytes), " + "net.inet.udp.maxdgram sysctl limits it to " + "%ld bytes.\n", size, maxdgram); + size = maxdgram; + /* No reason to return */ + } + } + + options_set_reply(OPT_BLKSIZE, "%d", size); + segsize = size; + pktsize = size + 4; + if (debug & DEBUG_OPTIONS) + tftp_log(LOG_DEBUG, "Setting blksize to '%s'", + options[OPT_BLKSIZE].o_reply); + + return (0); +} + +int +option_blksize2(int peer __unused) +{ + u_long maxdgram; + int size, i; + size_t len; + + int sizes[] = { + 8, 16, 32, 64, 128, 256, 512, 1024, + 2048, 4096, 8192, 16384, 32768, 0 + }; + + if (options[OPT_BLKSIZE2].o_request == NULL) + return (0); + + /* maximum size of an UDP packet according to the system */ + len = sizeof(maxdgram); + if (sysctlbyname("net.inet.udp.maxdgram", + &maxdgram, &len, NULL, 0) < 0) { + tftp_log(LOG_ERR, "sysctl: net.inet.udp.maxdgram"); + return (acting_as_client ? 1 : 0); + } + + size = atoi(options[OPT_BLKSIZE2].o_request); + for (i = 0; sizes[i] != 0; i++) { + if (size == sizes[i]) break; + } + if (sizes[i] == 0) { + tftp_log(LOG_INFO, + "Invalid blocksize2 (%d bytes), ignoring request", size); + return (acting_as_client ? 1 : 0); + } + + if (size > (int)maxdgram) { + for (i = 0; sizes[i+1] != 0; i++) { + if ((int)maxdgram < sizes[i+1]) break; + } + tftp_log(LOG_INFO, + "Invalid blocksize2 (%d bytes), net.inet.udp.maxdgram " + "sysctl limits it to %ld bytes.\n", size, maxdgram); + size = sizes[i]; + /* No need to return */ + } + + options_set_reply(OPT_BLKSIZE2, "%d", size); + segsize = size; + pktsize = size + 4; + if (debug & DEBUG_OPTIONS) + tftp_log(LOG_DEBUG, "Setting blksize2 to '%s'", + options[OPT_BLKSIZE2].o_reply); + + return (0); +} + +int +option_windowsize(int peer) +{ + int size; + + if (options[OPT_WINDOWSIZE].o_request == NULL) + return (0); + + size = atoi(options[OPT_WINDOWSIZE].o_request); + if (size < WINDOWSIZE_MIN || size > WINDOWSIZE_MAX) { + if (acting_as_client) { + tftp_log(LOG_ERR, + "Invalid windowsize (%d blocks), aborting", + size); + send_error(peer, EBADOP); + return (1); + } else { + tftp_log(LOG_WARNING, + "Invalid windowsize (%d blocks), ignoring request", + size); + return (0); + } + } + + /* XXX: Should force a windowsize of 1 for non-seekable files. */ + options_set_reply(OPT_WINDOWSIZE, "%d", size); + windowsize = size; + + if (debug & DEBUG_OPTIONS) + tftp_log(LOG_DEBUG, "Setting windowsize to '%s'", + options[OPT_WINDOWSIZE].o_reply); + + return (0); +} + +/* + * Append the available options to the header + */ +uint16_t +make_options(int peer __unused, char *buffer, uint16_t size) { + int i; + char *value; + const char *option; + uint16_t length; + uint16_t returnsize = 0; + + if (!options_rfc_enabled) return (0); + + for (i = 0; options[i].o_type != NULL; i++) { + if (options[i].rfc == 0 && !options_extra_enabled) + continue; + + option = options[i].o_type; + if (acting_as_client) + value = options[i].o_request; + else + value = options[i].o_reply; + if (value == NULL) + continue; + + length = strlen(value) + strlen(option) + 2; + if (size <= length) { + tftp_log(LOG_ERR, + "Running out of option space for " + "option '%s' with value '%s': " + "needed %d bytes, got %d bytes", + option, value, size, length); + continue; + } + + sprintf(buffer, "%s%c%s%c", option, '\000', value, '\000'); + size -= length; + buffer += length; + returnsize += length; + } + + return (returnsize); +} + +/* + * Parse the received options in the header + */ +int +parse_options(int peer, char *buffer, uint16_t size) +{ + int i, options_failed; + char *c, *cp, *option, *value; + + if (!options_rfc_enabled) return (0); + + /* Parse the options */ + cp = buffer; + options_failed = 0; + while (size > 0) { + option = cp; + i = get_field(peer, cp, size); + cp += i; + + value = cp; + i = get_field(peer, cp, size); + cp += i; + + /* We are at the end */ + if (*option == '\0') break; + + if (debug & DEBUG_OPTIONS) + tftp_log(LOG_DEBUG, + "option: '%s' value: '%s'", option, value); + + for (c = option; *c; c++) + if (isupper(*c)) + *c = tolower(*c); + for (i = 0; options[i].o_type != NULL; i++) { + if (strcmp(option, options[i].o_type) == 0) { + if (!acting_as_client) + options_set_request(i, "%s", value); + if (!options_extra_enabled && !options[i].rfc) { + tftp_log(LOG_INFO, + "Option '%s' with value '%s' found " + "but it is not an RFC option", + option, value); + continue; + } + if (options[i].o_handler) + options_failed += + (options[i].o_handler)(peer); + break; + } + } + if (options[i].o_type == NULL) + tftp_log(LOG_WARNING, + "Unknown option: '%s'", option); + + size -= strlen(option) + strlen(value) + 2; + } + + return (options_failed); +} + +/* + * Set some default values in the options + */ +void +init_options(void) +{ + + options_set_request(OPT_ROLLOVER, "0"); +} |