/* $OpenBSD: clparse.c,v 1.101 2016/09/01 13:27:04 krw Exp $ */ /* Parser for dhclient config and lease files. */ /* * Copyright (c) 1997 The Internet Software Consortium. * 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. * 3. Neither the name of The Internet Software Consortium nor the names * of its contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM 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 THE INTERNET SOFTWARE CONSORTIUM 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. * * This software has been written for the Internet Software Consortium * by Ted Lemon in cooperation with Vixie * Enterprises. To learn more about the Internet Software Consortium, * see ``http://www.vix.com/isc''. To learn more about Vixie * Enterprises, see ``http://www.vix.com''. */ #include #include #include #include #include #include #include #include #include #include #include #include "dhcp.h" #include "dhcpd.h" #include "dhctoken.h" void parse_client_statement(FILE *, struct interface_info *); int parse_X(FILE *, u_int8_t *, int); int parse_option_list(FILE *, u_int8_t *, size_t); void parse_interface_declaration(FILE *, struct interface_info *); void parse_client_lease_statement(FILE *, int, struct interface_info *); void parse_client_lease_declaration(FILE *, struct client_lease *, struct interface_info *); int parse_option_decl(FILE *, struct option_data *); void parse_reject_statement(FILE *); /* * client-conf-file :== client-declarations EOF * client-declarations :== * | client-declaration * | client-declarations client-declaration */ void read_client_conf(struct interface_info *ifi) { FILE *cfile; int token; new_parse(path_dhclient_conf); /* Set some defaults. */ config->link_timeout = 10; /* secs before going daemon w/o link */ config->timeout = 30; /* secs to wait for an OFFER */ config->select_interval = 0; /* secs to wait for other OFFERs */ config->reboot_timeout = 1; /* secs before giving up on reboot */ config->retry_interval = 1; /* secs before asking for OFFER */ config->backoff_cutoff = 10; /* max secs between packet retries */ config->initial_interval = 1; /* secs before 1st retry */ config->bootp_policy = ACCEPT; config->requested_options [config->requested_option_count++] = DHO_SUBNET_MASK; config->requested_options [config->requested_option_count++] = DHO_BROADCAST_ADDRESS; config->requested_options [config->requested_option_count++] = DHO_TIME_OFFSET; /* RFC 3442 says CLASSLESS_STATIC_ROUTES must be before ROUTERS! */ config->requested_options [config->requested_option_count++] = DHO_CLASSLESS_STATIC_ROUTES; config->requested_options [config->requested_option_count++] = DHO_ROUTERS; config->requested_options [config->requested_option_count++] = DHO_DOMAIN_NAME; config->requested_options [config->requested_option_count++] = DHO_DOMAIN_SEARCH; config->requested_options [config->requested_option_count++] = DHO_DOMAIN_NAME_SERVERS; config->requested_options [config->requested_option_count++] = DHO_HOST_NAME; config->requested_options [config->requested_option_count++] = DHO_BOOTFILE_NAME; config->requested_options [config->requested_option_count++] = DHO_TFTP_SERVER; if ((cfile = fopen(path_dhclient_conf, "r")) != NULL) { do { token = peek_token(NULL, cfile); if (token == EOF) break; parse_client_statement(cfile, ifi); } while (1); fclose(cfile); } } /* * lease-file :== client-lease-statements EOF * client-lease-statements :== * | client-lease-statements LEASE client-lease-statement */ void read_client_leases(struct interface_info *ifi) { FILE *cfile; int token; new_parse(path_dhclient_db); /* Open the lease file. If we can't open it, just return - we can safely trust the server to remember our state. */ if ((cfile = fopen(path_dhclient_db, "r")) == NULL) return; do { token = next_token(NULL, cfile); if (token == EOF) break; if (token != TOK_LEASE) { warning("Corrupt lease file - possible data loss!"); break; } parse_client_lease_statement(cfile, 0, ifi); } while (1); fclose(cfile); } /* * client-declaration :== * TOK_SEND option-decl | * TOK_DEFAULT option-decl | * TOK_SUPERSEDE option-decl | * TOK_APPEND option-decl | * TOK_PREPEND option-decl | * TOK_MEDIA string-list | * hardware-declaration | * TOK_REQUEST option-list | * TOK_REQUIRE option-list | * TOK_IGNORE option-list | * TOK_TIMEOUT number | * TOK_RETRY number | * TOK_SELECT_TIMEOUT number | * TOK_REBOOT number | * TOK_BACKOFF_CUTOFF number | * TOK_INITIAL_INTERVAL number | * interface-declaration | * TOK_LEASE client-lease-statement | * TOK_ALIAS client-lease-statement | * TOK_REJECT reject-statement */ void parse_client_statement(FILE *cfile, struct interface_info *ifi) { u_int8_t optlist[256]; char *string; int code, count, token; token = next_token(NULL, cfile); switch (token) { case TOK_SEND: parse_option_decl(cfile, &config->send_options[0]); break; case TOK_DEFAULT: code = parse_option_decl(cfile, &config->defaults[0]); if (code != -1) config->default_actions[code] = ACTION_DEFAULT; break; case TOK_SUPERSEDE: code = parse_option_decl(cfile, &config->defaults[0]); if (code != -1) config->default_actions[code] = ACTION_SUPERSEDE; break; case TOK_APPEND: code = parse_option_decl(cfile, &config->defaults[0]); if (code != -1) config->default_actions[code] = ACTION_APPEND; break; case TOK_PREPEND: code = parse_option_decl(cfile, &config->defaults[0]); if (code != -1) config->default_actions[code] = ACTION_PREPEND; break; case TOK_HARDWARE: parse_ethernet(cfile, &ifi->hw_address); break; case TOK_REQUEST: count = parse_option_list(cfile, optlist, sizeof(optlist)); if (count != -1) { config->requested_option_count = count; memcpy(config->requested_options, optlist, sizeof(config->requested_options)); } break; case TOK_REQUIRE: count = parse_option_list(cfile, optlist, sizeof(optlist)); if (count != -1) { config->required_option_count = count; memcpy(config->required_options, optlist, sizeof(config->required_options)); } break; case TOK_IGNORE: count = parse_option_list(cfile, optlist, sizeof(optlist)); if (count != -1) { config->ignored_option_count = count; memcpy(config->ignored_options, optlist, sizeof(config->ignored_options)); } break; case TOK_LINK_TIMEOUT: parse_lease_time(cfile, &config->link_timeout); break; case TOK_TIMEOUT: parse_lease_time(cfile, &config->timeout); break; case TOK_RETRY: parse_lease_time(cfile, &config->retry_interval); break; case TOK_SELECT_TIMEOUT: parse_lease_time(cfile, &config->select_interval); break; case TOK_REBOOT: parse_lease_time(cfile, &config->reboot_timeout); break; case TOK_BACKOFF_CUTOFF: parse_lease_time(cfile, &config->backoff_cutoff); break; case TOK_INITIAL_INTERVAL: parse_lease_time(cfile, &config->initial_interval); break; case TOK_INTERFACE: parse_interface_declaration(cfile, ifi); break; case TOK_LEASE: parse_client_lease_statement(cfile, 1, ifi); break; case TOK_ALIAS: case TOK_MEDIA: /* Deprecated and ignored. */ skip_to_semi(cfile); break; case TOK_REJECT: parse_reject_statement(cfile); break; case TOK_FILENAME: string = parse_string(cfile); free(config->filename); config->filename = string; break; case TOK_SERVER_NAME: string = parse_string(cfile); free(config->server_name); config->server_name = string; break; case TOK_FIXED_ADDR: if (parse_ip_addr(cfile, &config->address)) parse_semi(cfile); break; case TOK_NEXT_SERVER: if (parse_ip_addr(cfile, &config->next_server)) parse_semi(cfile); break; default: parse_warn("expecting a statement."); if (token != ';') skip_to_semi(cfile); break; } } int parse_X(FILE *cfile, u_int8_t *buf, int max) { int token; char *val; int len; token = peek_token(&val, cfile); if (token == TOK_NUMBER_OR_NAME) { len = 0; for (token = ':'; token == ':'; token = next_token(NULL, cfile)) { if (!parse_hex(cfile, &buf[len])) break; if (++len == max) break; if (peek_token(NULL, cfile) == ';') return (len); } if (token != ':') { parse_warn("expecting ':'."); skip_to_semi(cfile); return (-1); } else { parse_warn("expecting hex octet."); skip_to_semi(cfile); return (-1); } } else if (token == TOK_STRING) { token = next_token(&val, cfile); len = strlen(val); if (len + 1 > max) { parse_warn("string constant too long."); skip_to_semi(cfile); return (-1); } memcpy(buf, val, len + 1); } else { token = next_token(NULL, cfile); parse_warn("expecting string or hexadecimal data"); if (token != ';') skip_to_semi(cfile); return (-1); } return (len); } /* * option-list :== option_name | * option_list COMMA option_name */ int parse_option_list(FILE *cfile, u_int8_t *list, size_t sz) { int ix, i, j; int token; char *val; memset(list, DHO_PAD, sz); ix = 0; do { token = next_token(&val, cfile); if (token == ';' && ix == 0) { /* Empty list. */ return (0); } if (!is_identifier(token)) { parse_warn("expecting option name."); goto syntaxerror; } /* * 0 (DHO_PAD) and 255 (DHO_END) are not valid in option * lists. They are not really options and it makes no sense * to request, require or ignore them. */ for (i = 1; i < DHO_END; i++) if (!strcasecmp(dhcp_options[i].name, val)) break; if (i == DHO_END) { parse_warn("expecting option name."); goto syntaxerror; } if (ix == sz) { parse_warn("too many options."); goto syntaxerror; } /* Avoid storing duplicate options in the list. */ for (j = 0; j < ix && list[j] != i; j++) ; if (j == ix) list[ix++] = i; token = peek_token(NULL, cfile); if (token == ',') token = next_token(NULL, cfile); } while (token == ','); if (parse_semi(cfile)) return (ix); syntaxerror: if (token != ';') skip_to_semi(cfile); return (-1); } /* * interface-declaration :== * INTERFACE string LBRACE client-declarations RBRACE */ void parse_interface_declaration(FILE *cfile, struct interface_info *ifi) { char *val; int token; token = next_token(&val, cfile); if (token != TOK_STRING) { parse_warn("expecting interface name (in quotes)."); if (token != ';') skip_to_semi(cfile); return; } if (strcmp(ifi->name, val) != 0) { skip_to_semi(cfile); return; } token = next_token(&val, cfile); if (token != '{') { parse_warn("expecting left brace."); if (token != ';') skip_to_semi(cfile); return; } do { token = peek_token(&val, cfile); if (token == EOF) { parse_warn("unterminated interface declaration."); return; } if (token == '}') break; parse_client_statement(cfile, ifi); } while (1); token = next_token(&val, cfile); } /* * client-lease-statement :== * RBRACE client-lease-declarations LBRACE * * client-lease-declarations :== * | * client-lease-declaration | * client-lease-declarations client-lease-declaration */ void parse_client_lease_statement(FILE *cfile, int is_static, struct interface_info *ifi) { struct client_state *client = ifi->client; struct client_lease *lease, *lp, *pl; struct option_data *opt1, *opt2; int token; token = next_token(NULL, cfile); if (token != '{') { parse_warn("expecting left brace."); if (token != ';') skip_to_semi(cfile); return; } lease = calloc(1, sizeof(struct client_lease)); if (!lease) error("no memory for lease."); do { token = peek_token(NULL, cfile); if (token == EOF) { parse_warn("unterminated lease declaration."); free_client_lease(lease); return; } if (token == '}') break; parse_client_lease_declaration(cfile, lease, ifi); } while (1); token = next_token(NULL, cfile); /* * If the new lease is for an obsolete client-identifier, toss it. */ opt1 = &lease->options[DHO_DHCP_CLIENT_IDENTIFIER]; opt2 = &config->send_options[DHO_DHCP_CLIENT_IDENTIFIER]; if (opt1->len && opt2->len && (opt1->len != opt2->len || memcmp(opt1->data, opt2->data, opt1->len))) { note("Obsolete client identifier (%s) in recorded lease", pretty_print_option( DHO_DHCP_CLIENT_IDENTIFIER, opt1, 0)); free_client_lease(lease); return; } /* * The new lease will supersede a lease of the same type and for * the same address or the same SSID. */ TAILQ_FOREACH_SAFE(lp, &client->leases, next, pl) { if (lp->is_static != is_static) continue; if ((strcmp(lp->ssid, ifi->ssid) == 0) || (lp->address.s_addr == lease->address.s_addr)) { TAILQ_REMOVE(&client->leases, lp, next); lp->is_static = 0; /* Else it won't be freed. */ free_client_lease(lp); } } /* * If the lease is marked as static before now it will leak on parse * errors because free_client_lease() ignores attempts to free static * leases. */ lease->is_static = is_static; if (is_static) TAILQ_INSERT_TAIL(&client->leases, lease, next); else TAILQ_INSERT_HEAD(&client->leases, lease, next); } /* * client-lease-declaration :== * BOOTP | * INTERFACE string | * FIXED_ADDR ip_address | * FILENAME string | * SERVER_NAME string | * OPTION option-decl | * RENEW time-decl | * REBIND time-decl | * EXPIRE time-decl */ void parse_client_lease_declaration(FILE *cfile, struct client_lease *lease, struct interface_info *ifi) { char *val; int token; token = next_token(&val, cfile); switch (token) { case TOK_BOOTP: lease->is_bootp = 1; break; case TOK_INTERFACE: token = next_token(&val, cfile); if (token != TOK_STRING) { parse_warn("expecting interface name (in quotes)."); if (token != ';') skip_to_semi(cfile); return; } if (strcmp(ifi->name, val) != 0) { if (lease->is_static == 0) parse_warn("wrong interface name."); skip_to_semi(cfile); return; } break; case TOK_FIXED_ADDR: if (!parse_ip_addr(cfile, &lease->address)) return; break; case TOK_NEXT_SERVER: if (!parse_ip_addr(cfile, &lease->next_server)) return; break; case TOK_MEDIUM: skip_to_semi(cfile); return; case TOK_FILENAME: lease->filename = parse_string(cfile); return; case TOK_SERVER_NAME: lease->server_name = parse_string(cfile); return; case TOK_SSID: val = parse_string(cfile); if (val) strlcpy(lease->ssid, val, sizeof(lease->ssid)); free(val); return; case TOK_RENEW: lease->renewal = parse_date(cfile); return; case TOK_REBIND: lease->rebind = parse_date(cfile); return; case TOK_EXPIRE: lease->expiry = parse_date(cfile); return; case TOK_OPTION: parse_option_decl(cfile, lease->options); return; default: parse_warn("expecting lease declaration."); if (token != ';') skip_to_semi(cfile); return; } parse_semi(cfile); } int parse_option_decl(FILE *cfile, struct option_data *options) { char *val; int token; u_int8_t buf[4]; u_int8_t cidr[5]; u_int8_t hunkbuf[1024]; int hunkix = 0; char *fmt; struct in_addr ip_addr; u_int8_t *dp; int len, code; int nul_term = 0; token = next_token(&val, cfile); if (!is_identifier(token)) { parse_warn("expecting identifier after option keyword."); if (token != ';') skip_to_semi(cfile); return (-1); } /* Look up the actual option info. */ fmt = NULL; for (code = 0; code < 256; code++) if (strcmp(dhcp_options[code].name, val) == 0) break; if (code > 255) { parse_warn("unknown option name."); skip_to_semi(cfile); return (-1); } /* Parse the option data. */ do { for (fmt = dhcp_options[code].format; *fmt; fmt++) { if (*fmt == 'A') break; switch (*fmt) { case 'X': len = parse_X(cfile, &hunkbuf[hunkix], sizeof(hunkbuf) - hunkix); if (len == -1) return (-1); hunkix += len; break; case 't': /* Text string. */ token = next_token(&val, cfile); if (token != TOK_STRING) { parse_warn("expecting string."); if (token != ';') skip_to_semi(cfile); return (-1); } len = strlen(val); if (hunkix + len + 1 > sizeof(hunkbuf)) { parse_warn("option data buffer " "overflow"); skip_to_semi(cfile); return (-1); } memcpy(&hunkbuf[hunkix], val, len + 1); nul_term = 1; hunkix += len; break; case 'I': /* IP address. */ if (!parse_ip_addr(cfile, &ip_addr)) return (-1); len = sizeof(ip_addr); dp = (u_int8_t *)&ip_addr; alloc: if (hunkix + len > sizeof(hunkbuf)) { parse_warn("option data buffer " "overflow"); skip_to_semi(cfile); return (-1); } memcpy(&hunkbuf[hunkix], dp, len); hunkix += len; break; case 'l': /* Signed 32-bit integer. */ if (!parse_decimal(cfile, buf, *fmt)) { parse_warn("expecting signed 32-bit " "integer."); skip_to_semi(cfile); return (-1); } len = 4; dp = buf; goto alloc; case 'L': /* Unsigned 32-bit integer. */ if (!parse_decimal(cfile, buf, *fmt)) { parse_warn("expecting unsigned 32-bit " "integer."); skip_to_semi(cfile); return (-1); } len = 4; dp = buf; goto alloc; case 'S': /* Unsigned 16-bit integer. */ if (!parse_decimal(cfile, buf, *fmt)) { parse_warn("expecting unsigned 16-bit " "integer."); skip_to_semi(cfile); return (-1); } len = 2; dp = buf; goto alloc; case 'B': /* Unsigned 8-bit integer. */ if (!parse_decimal(cfile, buf, *fmt)) { parse_warn("expecting unsigned 8-bit " "integer."); skip_to_semi(cfile); return (-1); } len = 1; dp = buf; goto alloc; case 'f': /* Boolean flag. */ token = next_token(&val, cfile); if (!is_identifier(token)) { parse_warn("expecting identifier."); bad_flag: if (token != ';') skip_to_semi(cfile); return (-1); } if (!strcasecmp(val, "true") || !strcasecmp(val, "on")) buf[0] = 1; else if (!strcasecmp(val, "false") || !strcasecmp(val, "off")) buf[0] = 0; else { parse_warn("expecting boolean."); goto bad_flag; } len = 1; dp = buf; goto alloc; case 'C': if (!parse_cidr(cfile, cidr)) return (-1); len = 1 + (cidr[0] + 7) / 8; dp = cidr; goto alloc; default: warning("Bad format %c in parse_option_param.", *fmt); skip_to_semi(cfile); return (-1); } } token = peek_token(NULL, cfile); if (*fmt == 'A' && token == ',') token = next_token(NULL, cfile); } while (*fmt == 'A' && token == ','); if (!parse_semi(cfile)) return (-1); options[code].data = malloc(hunkix + nul_term); if (!options[code].data) error("out of memory allocating option data."); memcpy(options[code].data, hunkbuf, hunkix + nul_term); options[code].len = hunkix; return (code); } void parse_reject_statement(FILE *cfile) { struct reject_elem *elem; struct in_addr addr; int token; do { if (!parse_ip_addr(cfile, &addr)) return; elem = malloc(sizeof(struct reject_elem)); if (!elem) error("no memory for reject address!"); elem->addr = addr; TAILQ_INSERT_TAIL(&config->reject_list, elem, next); token = peek_token(NULL, cfile); if (token == ',') token = next_token(NULL, cfile); } while (token == ','); parse_semi(cfile); }