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- /* Copyright (c) 2001 Matej Pfajfar.
- * Copyright (c) 2001-2004, Roger Dingledine.
- * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
- * Copyright (c) 2007-2018, The Tor Project, Inc. */
- /* See LICENSE for licensing information */
- #include "core/or/or.h"
- #include "feature/dirparse/authcert_parse.h"
- #include "feature/dirparse/parsecommon.h"
- #include "feature/dirparse/sigcommon.h"
- #include "feature/dirparse/unparseable.h"
- #include "feature/nodelist/authcert.h"
- #include "lib/memarea/memarea.h"
- #include "feature/nodelist/authority_cert_st.h"
- /** List of tokens recognized in V3 authority certificates. */
- static token_rule_t dir_key_certificate_table[] = {
- #include "feature/dirparse/authcert_members.i"
- T1("fingerprint", K_FINGERPRINT, CONCAT_ARGS, NO_OBJ ),
- END_OF_TABLE
- };
- /** Parse a key certificate from <b>s</b>; point <b>end-of-string</b> to
- * the first character after the certificate. */
- authority_cert_t *
- authority_cert_parse_from_string(const char *s, const char **end_of_string)
- {
- /** Reject any certificate at least this big; it is probably an overflow, an
- * attack, a bug, or some other nonsense. */
- #define MAX_CERT_SIZE (128*1024)
- authority_cert_t *cert = NULL, *old_cert;
- smartlist_t *tokens = NULL;
- char digest[DIGEST_LEN];
- directory_token_t *tok;
- char fp_declared[DIGEST_LEN];
- char *eos;
- size_t len;
- int found;
- memarea_t *area = NULL;
- const char *s_dup = s;
- s = eat_whitespace(s);
- eos = strstr(s, "\ndir-key-certification");
- if (! eos) {
- log_warn(LD_DIR, "No signature found on key certificate");
- return NULL;
- }
- eos = strstr(eos, "\n-----END SIGNATURE-----\n");
- if (! eos) {
- log_warn(LD_DIR, "No end-of-signature found on key certificate");
- return NULL;
- }
- eos = strchr(eos+2, '\n');
- tor_assert(eos);
- ++eos;
- len = eos - s;
- if (len > MAX_CERT_SIZE) {
- log_warn(LD_DIR, "Certificate is far too big (at %lu bytes long); "
- "rejecting", (unsigned long)len);
- return NULL;
- }
- tokens = smartlist_new();
- area = memarea_new();
- if (tokenize_string(area,s, eos, tokens, dir_key_certificate_table, 0) < 0) {
- log_warn(LD_DIR, "Error tokenizing key certificate");
- goto err;
- }
- if (router_get_hash_impl(s, strlen(s), digest, "dir-key-certificate-version",
- "\ndir-key-certification", '\n', DIGEST_SHA1) < 0)
- goto err;
- tok = smartlist_get(tokens, 0);
- if (tok->tp != K_DIR_KEY_CERTIFICATE_VERSION || strcmp(tok->args[0], "3")) {
- log_warn(LD_DIR,
- "Key certificate does not begin with a recognized version (3).");
- goto err;
- }
- cert = tor_malloc_zero(sizeof(authority_cert_t));
- memcpy(cert->cache_info.signed_descriptor_digest, digest, DIGEST_LEN);
- tok = find_by_keyword(tokens, K_DIR_SIGNING_KEY);
- tor_assert(tok->key);
- cert->signing_key = tok->key;
- tok->key = NULL;
- if (crypto_pk_get_digest(cert->signing_key, cert->signing_key_digest))
- goto err;
- tok = find_by_keyword(tokens, K_DIR_IDENTITY_KEY);
- tor_assert(tok->key);
- cert->identity_key = tok->key;
- tok->key = NULL;
- tok = find_by_keyword(tokens, K_FINGERPRINT);
- tor_assert(tok->n_args);
- if (base16_decode(fp_declared, DIGEST_LEN, tok->args[0],
- strlen(tok->args[0])) != DIGEST_LEN) {
- log_warn(LD_DIR, "Couldn't decode key certificate fingerprint %s",
- escaped(tok->args[0]));
- goto err;
- }
- if (crypto_pk_get_digest(cert->identity_key,
- cert->cache_info.identity_digest))
- goto err;
- if (tor_memneq(cert->cache_info.identity_digest, fp_declared, DIGEST_LEN)) {
- log_warn(LD_DIR, "Digest of certificate key didn't match declared "
- "fingerprint");
- goto err;
- }
- tok = find_opt_by_keyword(tokens, K_DIR_ADDRESS);
- if (tok) {
- struct in_addr in;
- char *address = NULL;
- tor_assert(tok->n_args);
- /* XXX++ use some tor_addr parse function below instead. -RD */
- if (tor_addr_port_split(LOG_WARN, tok->args[0], &address,
- &cert->dir_port) < 0 ||
- tor_inet_aton(address, &in) == 0) {
- log_warn(LD_DIR, "Couldn't parse dir-address in certificate");
- tor_free(address);
- goto err;
- }
- cert->addr = ntohl(in.s_addr);
- tor_free(address);
- }
- tok = find_by_keyword(tokens, K_DIR_KEY_PUBLISHED);
- if (parse_iso_time(tok->args[0], &cert->cache_info.published_on) < 0) {
- goto err;
- }
- tok = find_by_keyword(tokens, K_DIR_KEY_EXPIRES);
- if (parse_iso_time(tok->args[0], &cert->expires) < 0) {
- goto err;
- }
- tok = smartlist_get(tokens, smartlist_len(tokens)-1);
- if (tok->tp != K_DIR_KEY_CERTIFICATION) {
- log_warn(LD_DIR, "Certificate didn't end with dir-key-certification.");
- goto err;
- }
- /* If we already have this cert, don't bother checking the signature. */
- old_cert = authority_cert_get_by_digests(
- cert->cache_info.identity_digest,
- cert->signing_key_digest);
- found = 0;
- if (old_cert) {
- /* XXXX We could just compare signed_descriptor_digest, but that wouldn't
- * buy us much. */
- if (old_cert->cache_info.signed_descriptor_len == len &&
- old_cert->cache_info.signed_descriptor_body &&
- tor_memeq(s, old_cert->cache_info.signed_descriptor_body, len)) {
- log_debug(LD_DIR, "We already checked the signature on this "
- "certificate; no need to do so again.");
- found = 1;
- }
- }
- if (!found) {
- if (check_signature_token(digest, DIGEST_LEN, tok, cert->identity_key, 0,
- "key certificate")) {
- goto err;
- }
- tok = find_by_keyword(tokens, K_DIR_KEY_CROSSCERT);
- if (check_signature_token(cert->cache_info.identity_digest,
- DIGEST_LEN,
- tok,
- cert->signing_key,
- CST_NO_CHECK_OBJTYPE,
- "key cross-certification")) {
- goto err;
- }
- }
- cert->cache_info.signed_descriptor_len = len;
- cert->cache_info.signed_descriptor_body = tor_malloc(len+1);
- memcpy(cert->cache_info.signed_descriptor_body, s, len);
- cert->cache_info.signed_descriptor_body[len] = 0;
- cert->cache_info.saved_location = SAVED_NOWHERE;
- if (end_of_string) {
- *end_of_string = eat_whitespace(eos);
- }
- SMARTLIST_FOREACH(tokens, directory_token_t *, t, token_clear(t));
- smartlist_free(tokens);
- if (area) {
- DUMP_AREA(area, "authority cert");
- memarea_drop_all(area);
- }
- return cert;
- err:
- dump_desc(s_dup, "authority cert");
- authority_cert_free(cert);
- SMARTLIST_FOREACH(tokens, directory_token_t *, t, token_clear(t));
- smartlist_free(tokens);
- if (area) {
- DUMP_AREA(area, "authority cert");
- memarea_drop_all(area);
- }
- return NULL;
- }
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