[or-cvs] [tor/master] Parse detached signature documents with multiple flavors and algorithms.
Nick Mathewson
nickm at seul.org
Mon Oct 19 04:48:28 UTC 2009
Author: Nick Mathewson <nickm at torproject.org>
Date: Wed, 16 Sep 2009 12:34:44 -0400
Subject: Parse detached signature documents with multiple flavors and algorithms.
Commit: 5576a3a094de49246e501bb24d1b3dc3a5d610b9
---
src/common/crypto.c | 12 ++++
src/common/crypto.h | 1 +
src/or/routerparse.c | 160 +++++++++++++++++++++++++++++++++++++++++---------
3 files changed, 146 insertions(+), 27 deletions(-)
diff --git a/src/common/crypto.c b/src/common/crypto.c
index ac0e628..f335f99 100644
--- a/src/common/crypto.c
+++ b/src/common/crypto.c
@@ -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 {
diff --git a/src/common/crypto.h b/src/common/crypto.h
index ed84680..c0a4526 100644
--- a/src/common/crypto.h
+++ b/src/common/crypto.h
@@ -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);
diff --git a/src/or/routerparse.c b/src/or/routerparse.c
index 285a550..21fe5f7 100644
--- a/src/or/routerparse.c
+++ b/src/or/routerparse.c
@@ -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,
@@ -490,10 +492,12 @@ 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 ),
- T1N("directory-signature", K_DIRECTORY_SIGNATURE, GE(2), NEED_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) {
- 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) {
- log_warn(LD_DIR, "Bad encoding on on consensus-digest in detached "
- "networkstatus signatures");
- goto err;
- }
+ /* 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;
+ }
+ 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)
+ 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;
- tor_assert(tok->n_args >= 2);
+ }
+
+ {
+ 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;
--
1.5.6.5
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