Parse detached signature documents with multiple flavors and algorithms. (5576a3a0) · Commits · Benjamin J. Thompson / Tor

src/common/crypto.c

+12 −0

Original line number	Diff line number	Diff line
		@@ -1481,6 +1481,18 @@ crypto_digest_algorithm_get_name(digest_algorithm_t alg)
		}
		}

		/** DOCDOC */
		int
		crypto_digest_algorithm_parse_name(const char *name)
		{
		if (!strcmp(name, "sha1"))
		return DIGEST_SHA1;
		else if (!strcmp(name, "sha256"))
		return DIGEST_SHA256;
		else
		return -1;
		}

		/** Intermediate information about the digest of a stream of data. */
		struct crypto_digest_env_t {
		union {

src/common/crypto.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -177,6 +177,7 @@ int crypto_digest256(char digest, const char m, size_t len,
		digest_algorithm_t algorithm);
		int crypto_digest_all(digests_t ds_out, const char m, size_t len);
		const char *crypto_digest_algorithm_get_name(digest_algorithm_t alg);
		int crypto_digest_algorithm_parse_name(const char *name);
		crypto_digest_env_t *crypto_new_digest_env(void);
		crypto_digest_env_t *crypto_new_digest256_env(digest_algorithm_t algorithm);
		void crypto_free_digest_env(crypto_digest_env_t *digest);

src/or/routerparse.c

+133 −27

Original line number	Diff line number	Diff line
		@@ -106,6 +106,8 @@ typedef enum {
		K_PARAMS,
		K_VOTE_DIGEST,
		K_CONSENSUS_DIGEST,
		K_ADDITIONAL_DIGEST,
		K_ADDITIONAL_SIGNATURE,
		K_CONSENSUS_METHODS,
		K_CONSENSUS_METHOD,
		K_LEGACY_DIR_KEY,
		@@ -490,9 +492,11 @@ static token_rule_t networkstatus_vote_footer_token_table[] = {
		/** List of tokens allowable in detached networkstatus signature documents. */
		static token_rule_t networkstatus_detached_signature_token_table[] = {
		T1_START("consensus-digest", K_CONSENSUS_DIGEST, GE(1), NO_OBJ ),
		T("additional-digest", K_ADDITIONAL_DIGEST,GE(3), NO_OBJ ),
		T1("valid-after", K_VALID_AFTER, CONCAT_ARGS, NO_OBJ ),
		T1("fresh-until", K_FRESH_UNTIL, CONCAT_ARGS, NO_OBJ ),
		T1("valid-until", K_VALID_UNTIL, CONCAT_ARGS, NO_OBJ ),
		T("additional-signature", K_ADDITIONAL_SIGNATURE, GE(4), NEED_OBJ ),
		T1N("directory-signature", K_DIRECTORY_SIGNATURE, GE(2), NEED_OBJ ),
		END_OF_TABLE
		};
		@@ -2771,6 +2775,31 @@ networkstatus_parse_vote_from_string(const char s, const char *eos_out,
		return ns;
		}

		/** DOCDOC */
		static digests_t *
		detached_get_digests(ns_detached_signatures_t sigs, const char flavor_name)
		{
		digests_t *d = strmap_get(sigs->digests, flavor_name);
		if (!d) {
		d = tor_malloc_zero(sizeof(digests_t));
		strmap_set(sigs->digests, flavor_name, d);
		}
		return d;
		}

		/** DOCDOC */
		static smartlist_t *
		detached_get_signatures(ns_detached_signatures_t *sigs,
		const char *flavor_name)
		{
		smartlist_t *sl = strmap_get(sigs->signatures, flavor_name);
		if (!sl) {
		sl = smartlist_create();
		strmap_set(sigs->signatures, flavor_name, sl);
		}
		return sl;
		}

		/** Parse a detached v3 networkstatus signature document between <b>s</b> and
		* <b>eos</b> and return the result. Return -1 on failure. */
		ns_detached_signatures_t *
		@@ -2780,19 +2809,13 @@ networkstatus_parse_detached_signatures(const char s, const char eos)
		* networkstatus_parse_vote_from_string(). */
		directory_token_t *tok;
		memarea_t *area = NULL;
		const char *flavor = "ns";
		digests_t *digests;
		smartlist_t *sig_list;

		smartlist_t *tokens = smartlist_create();
		ns_detached_signatures_t *sigs =
		tor_malloc_zero(sizeof(ns_detached_signatures_t));
		sigs->digests = strmap_new();
		sigs->signatures = strmap_new();
		digests = tor_malloc_zero(sizeof(digests_t));
		sig_list = smartlist_create();
		strmap_set(sigs->digests, flavor, digests);
		strmap_set(sigs->signatures, flavor, sig_list);

		if (!eos)
		eos = s + strlen(s);
		@@ -2804,18 +2827,57 @@ networkstatus_parse_detached_signatures(const char s, const char eos)
		goto err;
		}

		tok = find_by_keyword(tokens, K_CONSENSUS_DIGEST);
		if (strlen(tok->args[0]) != HEX_DIGEST_LEN) {
		/* Grab all the digest-like tokens. */
		SMARTLIST_FOREACH_BEGIN(tokens, directory_token_t *, _tok) {
		const char *algname;
		digest_algorithm_t alg;
		const char *flavor;
		const char *hexdigest;
		size_t expected_length;

		tok = _tok;

		if (tok->tp == K_CONSENSUS_DIGEST) {
		algname = "sha1";
		alg = DIGEST_SHA1;
		flavor = "ns";
		hexdigest = tok->args[0];
		} else if (tok->tp == K_ADDITIONAL_DIGEST) {
		int a = crypto_digest_algorithm_parse_name(tok->args[1]);
		if (a<0) {
		log_warn(LD_DIR, "Unrecognized algorithm name %s", tok->args[0]);
		continue;
		}
		alg = (digest_algorithm_t) a;
		flavor = tok->args[0];
		algname = tok->args[1];
		hexdigest = tok->args[2];
		} else {
		continue;
		}

		expected_length =
		(alg == DIGEST_SHA1) ? HEX_DIGEST_LEN : HEX_DIGEST256_LEN;

		if (strlen(hexdigest) != expected_length) {
		log_warn(LD_DIR, "Wrong length on consensus-digest in detached "
		"networkstatus signatures");
		goto err;
		}
		if (base16_decode(digests->d[DIGEST_SHA1], DIGEST_LEN,
		tok->args[0], strlen(tok->args[0])) < 0) {
		digests = detached_get_digests(sigs, flavor);
		tor_assert(digests);
		if (!tor_mem_is_zero(digests->d[alg], DIGEST256_LEN)) {
		log_warn(LD_DIR, "Multiple digests for %s with %s on detached "
		"signatures document", flavor, algname);
		continue;
		}
		if (base16_decode(digests->d[alg], DIGEST256_LEN,
		hexdigest, strlen(hexdigest)) < 0) {
		log_warn(LD_DIR, "Bad encoding on on consensus-digest in detached "
		"networkstatus signatures");
		goto err;
		}
		} SMARTLIST_FOREACH_END(_tok);

		tok = find_by_keyword(tokens, K_VALID_AFTER);
		if (parse_iso_time(tok->args[0], &sigs->valid_after)) {
		@@ -2836,14 +2898,43 @@ networkstatus_parse_detached_signatures(const char s, const char eos)
		}

		SMARTLIST_FOREACH_BEGIN(tokens, directory_token_t *, _tok) {
		const char *id_hexdigest;
		const char *sk_hexdigest;
		const char *algname;
		const char *flavor;
		digest_algorithm_t alg;

		char id_digest[DIGEST_LEN];
		char sk_digest[DIGEST_LEN];
		smartlist_t *siglist;
		document_signature_t *sig;
		int is_duplicate;

		tok = _tok;
		if (tok->tp != K_DIRECTORY_SIGNATURE)
		continue;
		if (tok->tp == K_DIRECTORY_SIGNATURE) {
		tor_assert(tok->n_args >= 2);
		flavor = "ns";
		algname = "sha1";
		id_hexdigest = tok->args[0];
		sk_hexdigest = tok->args[1];
		} else if (tok->tp == K_ADDITIONAL_SIGNATURE) {
		tor_assert(tok->n_args >= 4);
		flavor = tok->args[0];
		algname = tok->args[1];
		id_hexdigest = tok->args[2];
		sk_hexdigest = tok->args[3];
		} else {
		continue;
		}

		{
		int a = crypto_digest_algorithm_parse_name(algname);
		if (a<0) {
		log_warn(LD_DIR, "Unrecognized algorithm name %s", algname);
		continue;
		}
		alg = (digest_algorithm_t) a;
		}

		if (!tok->object_type \|\|
		strcmp(tok->object_type, "SIGNATURE") \|\|
		@@ -2852,21 +2943,36 @@ networkstatus_parse_detached_signatures(const char s, const char eos)
		goto err;
		}

		if (strlen(tok->args[0]) != HEX_DIGEST_LEN \|\|
		if (strlen(id_hexdigest) != HEX_DIGEST_LEN \|\|
		base16_decode(id_digest, sizeof(id_digest),
		tok->args[0], HEX_DIGEST_LEN) < 0) {
		id_hexdigest, HEX_DIGEST_LEN) < 0) {
		log_warn(LD_DIR, "Error decoding declared identity %s in "
		"network-status vote.", escaped(tok->args[0]));
		"network-status vote.", escaped(id_hexdigest));
		goto err;
		}
		if (strlen(tok->args[1]) != HEX_DIGEST_LEN \|\|
		base16_decode(sk_digest, sizeof(sk_digest),
		tok->args[1], HEX_DIGEST_LEN) < 0) {
		sk_hexdigest, HEX_DIGEST_LEN) < 0) {
		log_warn(LD_DIR, "Error decoding declared digest %s in "
		"network-status vote.", escaped(tok->args[1]));
		"network-status vote.", escaped(sk_hexdigest));
		goto err;
		}

		siglist = detached_get_signatures(sigs, flavor);
		is_duplicate = 0;
		SMARTLIST_FOREACH(siglist, document_signature_t *, s, {
		if (s->alg == alg &&
		!memcmp(id_digest, s->identity_digest, DIGEST_LEN) &&
		!memcmp(sk_digest, s->signing_key_digest, DIGEST_LEN)) {
		is_duplicate = 1;
		}
		});
		if (is_duplicate) {
		log_warn(LD_DIR, "Two signatures with identical keys and algorithm "
		"found.");
		continue;
		}

		sig = tor_malloc_zero(sizeof(document_signature_t));
		sig->alg = DIGEST_SHA1;
		memcpy(sig->identity_digest, id_digest, DIGEST_LEN);
		@@ -2878,7 +2984,7 @@ networkstatus_parse_detached_signatures(const char s, const char eos)
		sig->signature = tor_memdup(tok->object_body, tok->object_size);
		sig->signature_len = (int) tok->object_size;

		smartlist_add(sig_list, sig);
		smartlist_add(siglist, sig);
		} SMARTLIST_FOREACH_END(_tok);

		goto done;