/* * ldns-keyfetcher retrieves the DNSKEYS for a certain domain * It traces the authoritatives nameservers down from the root * And uses TCP, to minimize spoofing danger. * * (c) NLnet Labs, 2006 - 2008 * See the file LICENSE for the license */ #include "config.h" #include #include int verbosity = 0; /* 0=use both ip4 and ip6 (default). 1=ip4only. 2=ip6only. */ uint8_t address_family = 0; bool store_in_file = false; static void usage(FILE *fp, char *prog) { fprintf(fp, "%s domain\n", prog); fprintf(fp, " retrieve the dnskeys for a domain\n"); fprintf(fp, "Options:\n"); fprintf(fp, "-4\t\tUse IPv4 only\n"); fprintf(fp, "-6\t\tUse IPv6 only\n"); fprintf(fp, "-h\t\tShow this help\n"); fprintf(fp, "-i\t\tInsecurer mode; don't do checks, just query for the keys\n"); fprintf(fp, "-r \tUse file to read root hints from\n"); fprintf(fp, "-s\t\tDon't print the keys but store them in files\n\t\tcalled K.+.+.key\n"); fprintf(fp, "-v \tVerbosity level (0-5, not verbose-very verbose)\n"); } static ldns_rr_list * retrieve_dnskeys(ldns_resolver *local_res, ldns_rdf *name, ldns_rr_type t, ldns_rr_class c, ldns_rr_list *dns_root) { ldns_resolver *res; ldns_pkt *p; ldns_rr_list *new_nss_a; ldns_rr_list *new_nss_aaaa; ldns_rr_list *final_answer; ldns_rr_list *new_nss; ldns_rr_list *ns_addr; ldns_rr_list *ns_addr2; uint16_t loop_count; ldns_rdf *pop; ldns_status status; size_t i; size_t nss_i; ldns_rr_list *answer_list = NULL; ldns_rr_list *authority_list = NULL; size_t last_nameserver_count; ldns_rdf **last_nameservers; loop_count = 0; new_nss_a = NULL; new_nss_aaaa = NULL; new_nss = NULL; ns_addr = NULL; ns_addr2 = NULL; final_answer = NULL; p = ldns_pkt_new(); res = ldns_resolver_new(); if (!p || !res) { fprintf(stderr, "Memory allocation failed"); return NULL; } if (verbosity >= 2) { printf("Finding dnskey data for zone: "); ldns_rdf_print(stdout, name); printf("\n\n"); } /* transfer some properties of local_res to res, * because they were given on the commandline */ ldns_resolver_set_ip6(res, ldns_resolver_ip6(local_res)); ldns_resolver_set_port(res, ldns_resolver_port(local_res)); ldns_resolver_set_debug(res, ldns_resolver_debug(local_res)); ldns_resolver_set_dnssec(res, ldns_resolver_dnssec(local_res)); ldns_resolver_set_fail(res, ldns_resolver_fail(local_res)); ldns_resolver_set_usevc(res, ldns_resolver_usevc(local_res)); ldns_resolver_set_random(res, ldns_resolver_random(local_res)); ldns_resolver_set_recursive(res, false); /* setup the root nameserver in the new resolver */ status = ldns_resolver_push_nameserver_rr_list(res, dns_root); if (status != LDNS_STATUS_OK) { fprintf(stderr, "Error setting root nameservers in resolver: %s\n", ldns_get_errorstr_by_id(status)); return NULL; } ldns_pkt_free(p); status = ldns_resolver_send(&p, res, name, t, c, 0); if (status != LDNS_STATUS_OK) { fprintf(stderr, "Error querying root servers: %s\n", ldns_get_errorstr_by_id(status)); return NULL; } if (ldns_pkt_get_rcode(p) != LDNS_RCODE_NOERROR) { printf("Error in packet:\n"); ldns_pkt_print(stdout, p); return NULL; } if (verbosity >= 4) { ldns_pkt_print(stdout, p); printf("\n\n"); } /* from now on, use TCP */ ldns_resolver_set_usevc(res, true); while(status == LDNS_STATUS_OK && ldns_pkt_reply_type(p) == LDNS_PACKET_REFERRAL) { if (verbosity >= 3) { printf("This is a delegation!\n\n"); } if (address_family == 0 || address_family == 1) { new_nss_a = ldns_pkt_rr_list_by_type(p, LDNS_RR_TYPE_A, LDNS_SECTION_ADDITIONAL); } else { new_nss_a = ldns_rr_list_new(); } if (address_family == 0 || address_family == 2) { new_nss_aaaa = ldns_pkt_rr_list_by_type(p, LDNS_RR_TYPE_AAAA, LDNS_SECTION_ADDITIONAL); } else { new_nss_aaaa = ldns_rr_list_new(); } new_nss = ldns_pkt_rr_list_by_type(p, LDNS_RR_TYPE_NS, LDNS_SECTION_AUTHORITY); /* remove the old nameserver from the resolver */ while((pop = ldns_resolver_pop_nameserver(res))) { ldns_rdf_deep_free(pop); } /* also check for new_nss emptyness */ if (!new_nss_aaaa && !new_nss_a) { /* * no nameserver found!!! * try to resolve the names we do got */ if (verbosity >= 3) { printf("Did not get address record for nameserver, doing seperate query.\n"); } ns_addr = ldns_rr_list_new(); for(i = 0; (size_t) i < ldns_rr_list_rr_count(new_nss); i++) { /* get the name of the nameserver */ pop = ldns_rr_rdf(ldns_rr_list_rr(new_nss, i), 0); if (!pop) { break; } /* retrieve it's addresses */ ns_addr2 = ldns_get_rr_list_addr_by_name(local_res, pop, c, 0); if (!ldns_rr_list_cat(ns_addr, ns_addr2)) { fprintf(stderr, "Internal error adding nameserver address.\n"); exit(EXIT_FAILURE); } ldns_rr_list_free(ns_addr2); } if (ns_addr) { if (ldns_resolver_push_nameserver_rr_list(res, ns_addr) != LDNS_STATUS_OK) { fprintf(stderr, "Error adding new nameservers"); ldns_pkt_free(p); return NULL; } ldns_rr_list_deep_free(ns_addr); } else { ldns_rr_list_print(stdout, ns_addr); fprintf(stderr, "Could not find the nameserver ip addr; abort"); ldns_pkt_free(p); return NULL; } } /* normally, the first working ns is used, but we need all now, so do it one by one * if the answer is null, take it from the next resolver * if the answer is not, compare it to that of the next resolver * error if different, continue if the same * if answer list null and no resolvers left die. */ ldns_rr_list_deep_free(answer_list); ldns_rr_list_deep_free(authority_list); answer_list = NULL; authority_list = NULL; for (nss_i = 0; nss_i < ldns_rr_list_rr_count(new_nss_aaaa); nss_i++) { while((pop = ldns_resolver_pop_nameserver(res))) { ldns_rdf_deep_free(pop); } status = ldns_resolver_push_nameserver(res, ldns_rr_rdf(ldns_rr_list_rr(new_nss_aaaa, nss_i), 0)); if (status != LDNS_STATUS_OK) { fprintf(stderr, "Error adding nameserver to resolver: %s\n", ldns_get_errorstr_by_id(status)); } if (verbosity >= 1) { fprintf(stdout, "Querying nameserver: "); ldns_rdf_print(stdout, ldns_rr_owner(ldns_rr_list_rr(new_nss_aaaa, nss_i))); fprintf(stdout, " ("); ldns_rdf_print(stdout, ldns_rr_rdf(ldns_rr_list_rr(new_nss_aaaa, nss_i), 0)); fprintf(stdout, ")\n"); } status = ldns_resolver_push_nameserver(res, ldns_rr_rdf(ldns_rr_list_rr(new_nss_aaaa, nss_i), 0)); if (status != LDNS_STATUS_OK) { fprintf(stderr, "Error adding nameserver to resolver: %s\n", ldns_get_errorstr_by_id(status)); } ldns_pkt_free(p); status = ldns_resolver_send(&p, res, name, t, c, 0); if (status == LDNS_STATUS_OK && p) { if (ldns_pkt_get_rcode(p) != LDNS_RCODE_NOERROR) { printf("Error in packet:\n"); ldns_pkt_print(stdout, p); return NULL; } if (verbosity >= 4) { ldns_pkt_print(stdout, p); printf("\n\n"); } if (answer_list) { if (verbosity >= 2) { printf("Comparing answer list of answer to previous\n\n"); } ldns_rr_list_sort(ldns_pkt_answer(p)); ldns_rr_list_sort(answer_list); if (ldns_rr_list_compare(answer_list, ldns_pkt_answer(p)) != 0) { fprintf(stderr, "ERROR: different answer answer from nameserver\n"); fprintf(stderr, "\nI had (from previous servers):\n"); ldns_rr_list_print(stderr, answer_list); fprintf(stderr, "\nI received (from nameserver at "); ldns_rdf_print(stderr, ldns_resolver_nameservers(res)[0]); fprintf(stderr, "):\n"); ldns_rr_list_print(stderr, ldns_pkt_answer(p)); exit(EXIT_FAILURE); } } else { answer_list = ldns_rr_list_clone(ldns_pkt_answer(p)); ldns_rr_list_sort(answer_list); if (verbosity >= 2) { printf("First answer list for this set, nothing to compare with\n\n"); } } if (authority_list) { if (verbosity >= 2) { printf("Comparing authority list of answer to previous\n\n"); } ldns_rr_list_sort(ldns_pkt_authority(p)); ldns_rr_list_sort(authority_list); if (ldns_rr_list_compare(authority_list, ldns_pkt_authority(p)) != 0) { fprintf(stderr, "ERROR: different authority answer from nameserver\n"); fprintf(stderr, "\nI had (from previous servers):\n"); ldns_rr_list_print(stderr, authority_list); fprintf(stderr, "\nI received (from nameserver at "); ldns_rdf_print(stderr, ldns_resolver_nameservers(res)[0]); fprintf(stderr, "):\n"); ldns_rr_list_print(stderr, ldns_pkt_authority(p)); exit(EXIT_FAILURE); } } else { authority_list = ldns_rr_list_clone(ldns_pkt_authority(p)); ldns_rr_list_sort(authority_list); if (verbosity >= 2) { printf("First authority list for this set, nothing to compare with\n\n"); } if (verbosity >= 3) { printf("NS RRset:\n"); ldns_rr_list_print(stdout, authority_list); printf("\n"); } } } } ldns_rr_list_deep_free(answer_list); ldns_rr_list_deep_free(authority_list); answer_list = NULL; authority_list = NULL; for (nss_i = 0; nss_i < ldns_rr_list_rr_count(new_nss_a); nss_i++) { while((pop = ldns_resolver_pop_nameserver(res))) {ldns_rdf_deep_free(pop); } if (verbosity >= 1) { fprintf(stdout, "Querying nameserver: "); ldns_rdf_print(stdout, ldns_rr_owner(ldns_rr_list_rr(new_nss_a, nss_i))); fprintf(stdout, " ("); ldns_rdf_print(stdout, ldns_rr_rdf(ldns_rr_list_rr(new_nss_a, nss_i), 0)); fprintf(stdout, ")\n"); } status = ldns_resolver_push_nameserver(res, ldns_rr_rdf(ldns_rr_list_rr(new_nss_a, nss_i), 0)); if (status != LDNS_STATUS_OK) { fprintf(stderr, "Error adding nameserver to resolver: %s\n", ldns_get_errorstr_by_id(status)); } ldns_pkt_free(p); status = ldns_resolver_send(&p, res, name, t, c, 0); if (status == LDNS_STATUS_OK) { if (ldns_pkt_get_rcode(p) != LDNS_RCODE_NOERROR) { printf("Error in packet:\n"); ldns_pkt_print(stdout, p); return NULL; } if (verbosity >= 4) { ldns_pkt_print(stdout, p); printf("\n\n"); } if (answer_list) { if (verbosity >= 2) { printf("Comparing answer list of answer to previous\n\n"); } ldns_rr_list_sort(ldns_pkt_answer(p)); ldns_rr_list_sort(answer_list); if (ldns_rr_list_compare(answer_list, ldns_pkt_answer(p)) != 0) { fprintf(stderr, "ERROR: different answer answer from nameserver\n"); fprintf(stderr, "\nI had (from previous servers):\n"); ldns_rr_list_print(stderr, answer_list); fprintf(stderr, "\nI received (from nameserver at "); ldns_rdf_print(stderr, ldns_resolver_nameservers(res)[0]); fprintf(stderr, "):\n"); ldns_rr_list_print(stderr, ldns_pkt_answer(p)); exit(EXIT_FAILURE); } } else { if (verbosity >= 2) { printf("First answer list for this set, nothing to compare with\n\n"); } answer_list = ldns_rr_list_clone(ldns_pkt_answer(p)); ldns_rr_list_sort(answer_list); } if (authority_list) { if (verbosity >= 2) { printf("Comparing authority list of answer to previous\n\n"); } ldns_rr_list_sort(ldns_pkt_authority(p)); ldns_rr_list_sort(authority_list); if (ldns_rr_list_compare(authority_list, ldns_pkt_authority(p)) != 0) { fprintf(stderr, "ERROR: different authority answer from nameserver\n"); fprintf(stderr, "\nI had (from previous servers):\n"); ldns_rr_list_print(stderr, authority_list); fprintf(stderr, "\nI received (from nameserver at "); ldns_rdf_print(stderr, ldns_resolver_nameservers(res)[0]); fprintf(stderr, "):\n"); ldns_rr_list_print(stderr, ldns_pkt_authority(p)); exit(EXIT_FAILURE); } } else { if (verbosity >= 2) { printf("First authority list for this set, nothing to compare with\n\n"); } authority_list = ldns_rr_list_clone(ldns_pkt_authority(p)); ldns_rr_list_sort(authority_list); if (verbosity >= 3) { printf("NS RRset:\n"); ldns_rr_list_print(stdout, authority_list); printf("\n"); } } } } ldns_rr_list_deep_free(authority_list); authority_list = NULL; if (loop_count++ > 20) { /* unlikely that we are doing something usefull */ fprintf(stderr, "Looks like we are looping"); ldns_pkt_free(p); return NULL; } ldns_pkt_free(p); if (verbosity >= 3) { fprintf(stdout, "This level ok. Continuing to next.\n\n"); } status = ldns_resolver_send(&p, res, name, t, c, 0); if (status != LDNS_STATUS_OK) { fprintf(stderr, "Error querying root servers: %s\n", ldns_get_errorstr_by_id(status)); return NULL; } if (ldns_pkt_get_rcode(p) != LDNS_RCODE_NOERROR) { printf("Error in packet:\n"); ldns_pkt_print(stdout, p); return NULL; } if (verbosity >= 4) { ldns_pkt_print(stdout, p); printf("\n\n"); } ldns_rr_list_deep_free(new_nss_aaaa); ldns_rr_list_deep_free(new_nss_a); ldns_rr_list_deep_free(new_nss); new_nss_aaaa = NULL; new_nss_a = NULL; ns_addr = NULL; } ldns_rr_list_deep_free(answer_list); answer_list = NULL; /* clone the nameserver list, we are going to handle them one by one */ last_nameserver_count = 0; last_nameservers = LDNS_XMALLOC(ldns_rdf *, ldns_resolver_nameserver_count(res)); pop = NULL; while((pop = ldns_resolver_pop_nameserver(res))) { last_nameservers[last_nameserver_count] = pop; last_nameserver_count++; } for (nss_i = 0; nss_i < last_nameserver_count; nss_i++) { /* remove previous nameserver */ while((pop = ldns_resolver_pop_nameserver(res))) { ldns_rdf_deep_free(pop); } if (verbosity >= 1) { printf("Querying nameserver: "); ldns_rdf_print(stdout, last_nameservers[nss_i]); printf("\n"); } status = ldns_resolver_push_nameserver(res, last_nameservers[nss_i]); if (status != LDNS_STATUS_OK) { fprintf(stderr, "Error adding nameserver to resolver: %s\n", ldns_get_errorstr_by_id(status)); } ldns_pkt_free(p); status = ldns_resolver_send(&p, res, name, t, c, 0); if (!p) { fprintf(stderr, "no packet received\n"); return NULL; } if (status == LDNS_STATUS_RES_NO_NS) { fprintf(stderr, "Error: nameserver at "); ldns_rdf_print(stderr, last_nameservers[nss_i]); fprintf(stderr, " not responding. Unable to check RRset here, aborting.\n"); return NULL; } if (ldns_pkt_get_rcode(p) != LDNS_RCODE_NOERROR) { printf("Error in packet:\n"); ldns_pkt_print(stdout, p); return NULL; } if (answer_list) { if (verbosity >= 2) { printf("1Comparing answer rr list of answer to previous\n"); } ldns_rr_list_sort(ldns_pkt_answer(p)); ldns_rr_list_sort(answer_list); if (ldns_rr_list_compare(answer_list, ldns_pkt_answer(p)) != 0) { printf("ERROR: different answer section in response from nameserver\n"); fprintf(stderr, "\nI had:\n"); ldns_rr_list_print(stderr, answer_list); fprintf(stderr, "\nI received (from nameserver at "); ldns_rdf_print(stderr, ldns_resolver_nameservers(res)[0]); fprintf(stderr, "):\n"); ldns_rr_list_print(stderr, ldns_pkt_answer(p)); exit(EXIT_FAILURE); } } else { if (verbosity >= 2) { printf("First answer rr list for this set, nothing to compare with\n"); } answer_list = ldns_rr_list_clone(ldns_pkt_answer(p)); if (verbosity >= 3) { printf("DNSKEY RRset:\n"); ldns_rr_list_print(stdout, answer_list); } } } for (nss_i = 0; nss_i < last_nameserver_count; nss_i++) { ldns_rdf_deep_free(last_nameservers[nss_i]); } LDNS_FREE(last_nameservers); ldns_resolver_deep_free(res); ldns_pkt_free(p); return answer_list; } /* * The file with the given path should contain a list of NS RRs * for the root zone and A records for those NS RRs. * Read them, check them, and append the a records to the rr list given. */ ldns_rr_list * read_root_hints(const char *filename) { FILE *fp = NULL; int line_nr = 0; ldns_zone *z; ldns_status status; ldns_rr_list *addresses = NULL; ldns_rr *rr; size_t i; fp = fopen(filename, "r"); if (!fp) { fprintf(stderr, "Unable to open %s for reading: %s\n", filename, strerror(errno)); return NULL; } status = ldns_zone_new_frm_fp_l(&z, fp, NULL, 0, 0, &line_nr); fclose(fp); if (status != LDNS_STATUS_OK) { fprintf(stderr, "Error reading root hints file: %s\n", ldns_get_errorstr_by_id(status)); return NULL; } else { addresses = ldns_rr_list_new(); for (i = 0; i < ldns_rr_list_rr_count(ldns_zone_rrs(z)); i++) { rr = ldns_rr_list_rr(ldns_zone_rrs(z), i); if ((address_family == 0 || address_family == 1) && ldns_rr_get_type(rr) == LDNS_RR_TYPE_A ) { ldns_rr_list_push_rr(addresses, ldns_rr_clone(rr)); } if ((address_family == 0 || address_family == 2) && ldns_rr_get_type(rr) == LDNS_RR_TYPE_AAAA) { ldns_rr_list_push_rr(addresses, ldns_rr_clone(rr)); } } ldns_zone_deep_free(z); return addresses; } } int main(int argc, char *argv[]) { ldns_resolver *res; ldns_rdf *ns; ldns_rdf *domain; ldns_rr_list *l = NULL; ldns_rr_list *dns_root = NULL; const char *root_file = "/etc/named.root"; ldns_status status; int i; char *domain_str; char *outputfile_str; ldns_buffer *outputfile_buffer; FILE *outputfile; ldns_rr *k; bool insecure = false; ldns_pkt *pkt; domain = NULL; res = NULL; if (argc < 2) { usage(stdout, argv[0]); exit(EXIT_FAILURE); } else { for (i = 1; i < argc; i++) { if (strncmp("-4", argv[i], 3) == 0) { if (address_family != 0) { fprintf(stderr, "Options -4 and -6 cannot be specified at the same time\n"); exit(EXIT_FAILURE); } address_family = 1; } else if (strncmp("-6", argv[i], 3) == 0) { if (address_family != 0) { fprintf(stderr, "Options -4 and -6 cannot be specified at the same time\n"); exit(EXIT_FAILURE); } address_family = 2; } else if (strncmp("-h", argv[i], 3) == 0) { usage(stdout, argv[0]); exit(EXIT_SUCCESS); } else if (strncmp("-i", argv[i], 2) == 0) { insecure = true; } else if (strncmp("-r", argv[i], 2) == 0) { if (strlen(argv[i]) > 2) { root_file = argv[i]+2; } else if (i+1 >= argc) { usage(stdout, argv[0]); exit(EXIT_FAILURE); } else { root_file = argv[i+1]; i++; } } else if (strncmp("-s", argv[i], 3) == 0) { store_in_file = true; } else if (strncmp("-v", argv[i], 2) == 0) { if (strlen(argv[i]) > 2) { verbosity = atoi(argv[i]+2); } else if (i+1 > argc) { usage(stdout, argv[0]); exit(EXIT_FAILURE); } else { verbosity = atoi(argv[i+1]); i++; } } else { /* create a rdf from the command line arg */ if (domain) { fprintf(stdout, "You can only specify one domain at a time\n"); exit(EXIT_FAILURE); } domain = ldns_dname_new_frm_str(argv[i]); } } if (!domain) { usage(stdout, argv[0]); exit(EXIT_FAILURE); } } dns_root = read_root_hints(root_file); if (!dns_root) { fprintf(stderr, "cannot read the root hints file\n"); exit(EXIT_FAILURE); } /* create a new resolver from /etc/resolv.conf */ status = ldns_resolver_new_frm_file(&res, NULL); if (status != LDNS_STATUS_OK) { fprintf(stderr, "Warning: Unable to create stub resolver from /etc/resolv.conf:\n"); fprintf(stderr, "%s\n", ldns_get_errorstr_by_id(status)); fprintf(stderr, "defaulting to nameserver at 127.0.0.1 for separate nameserver name lookups\n"); res = ldns_resolver_new(); ns = ldns_rdf_new_frm_str(LDNS_RDF_TYPE_A, "127.0.0.1"); status = ldns_resolver_push_nameserver(res, ns); if (status != LDNS_STATUS_OK) { fprintf(stderr, "Unable to create stub resolver: %s\n", ldns_get_errorstr_by_id(status)); exit(EXIT_FAILURE); } ldns_rdf_deep_free(ns); } ldns_resolver_set_ip6(res, address_family); if (insecure) { pkt = ldns_resolver_query(res, domain, LDNS_RR_TYPE_DNSKEY, LDNS_RR_CLASS_IN, LDNS_RD); if (pkt) { l = ldns_pkt_rr_list_by_type(pkt, LDNS_RR_TYPE_DNSKEY, LDNS_SECTION_ANY_NOQUESTION); } } else { l = retrieve_dnskeys(res, domain, LDNS_RR_TYPE_DNSKEY, LDNS_RR_CLASS_IN, dns_root); } /* separator for result data and verbosity data */ if (verbosity > 0) { fprintf(stdout, "; ---------------------------\n"); fprintf(stdout, "; Got the following keys:\n"); } if (l) { if (store_in_file) { /* create filename: * K.+.+.key */ for (i = 0; (size_t) i < ldns_rr_list_rr_count(l); i++) { k = ldns_rr_list_rr(l, (size_t) i); outputfile_buffer = ldns_buffer_new(300); domain_str = ldns_rdf2str(ldns_rr_owner(k)); ldns_buffer_printf(outputfile_buffer, "K%s+%03u+%05u.key", domain_str, ldns_rdf2native_int8(ldns_rr_rdf(k, 2)), (unsigned int) ldns_calc_keytag(k)); outputfile_str = ldns_buffer_export(outputfile_buffer); if (verbosity >= 1) { fprintf(stdout, "Writing key to file %s\n", outputfile_str); } outputfile = fopen(outputfile_str, "w"); if (!outputfile) { fprintf(stderr, "Error writing key to file %s: %s\n", outputfile_str, strerror(errno)); } else { ldns_rr_print(outputfile, k); fclose(outputfile); } LDNS_FREE(domain_str); LDNS_FREE(outputfile_str); LDNS_FREE(outputfile_buffer); } } else { ldns_rr_list_print(stdout, l); } } else { fprintf(stderr, "no answer packet received, stub resolver config:\n"); ldns_resolver_print(stderr, res); } printf("\n"); ldns_rdf_deep_free(domain); ldns_resolver_deep_free(res); ldns_rr_list_deep_free(l); ldns_rr_list_deep_free(dns_root); return EXIT_SUCCESS; }