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r12639@catbus: nickm | 2007-05-02 17:37:49 -0400

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Start implementing key certificate parsing.  Note TODO items for combined 101/103.


svn:r10097
This commit is contained in:
Nick Mathewson 2007-05-02 21:37:55 +00:00
parent 9279c1d5fe
commit e2a49ed2f4
3 changed files with 262 additions and 28 deletions
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17
doc/TODO
View File

@ -53,13 +53,23 @@ N . Document transport and natdport
Things we'd like to do in 0.2.0.x:
- Proposals:
- 101: Voting on the Tor Directory System
. 101: Voting on the Tor Directory System
- Prepare ASAP for new voting formats
- Don't flip out with warnings when voting-related URLs are
uploaded/downloaded.
- Finalize proposal
. Finalize proposal
- Merge 101 and 103 and dir-spec.txt into a new dir-spec.txt; fork
the existing one into dir-spec-v2.txt.
- Get authorities voting
- Implement parsing for new document formats
. Implement parsing for new document formats
o Parse key certificates
- Parse votes and consensuses
- Unit tests for above
- Code to manage key certificates
- Cache on disk
- Download as needed
- Serve list as needed.
- Avoid double-checking signatures every time we get a vote.
- Code to generate votes
- Code to generate consensus from a list of votes
- Add a signature to a consensus.
@ -85,6 +95,7 @@ Things we'd like to do in 0.2.0.x:
- 108: Base "Stable" Flag on Mean Time Between Failures
- 109: No more than one server per IP address
- 103: Splitting identity key from regularly used signing key
- Merge with 101 into a new dir-spec.txt
- 113: Simplifying directory authority administration
- 110: prevent infinite-length circuits (phase one)
- servers should recognize relay_extend cells and pass them

14
src/or/or.h
View File

@ -1300,6 +1300,14 @@ typedef struct extend_info_t {
crypto_pk_env_t *onion_key; /**< Current onionskin key. */
} extend_info_t;
/** DOCDOC */
typedef struct authority_cert_t {
signed_descriptor_t cache_info;
crypto_pk_env_t *identity_key;
crypto_pk_env_t *signing_key;
time_t expires;
} authority_cert_t;
#define CRYPT_PATH_MAGIC 0x70127012u
/** Holds accounting information for a single step in the layered encryption
@ -3198,5 +3206,11 @@ void dump_distinct_digest_count(int severity);
networkstatus_t *networkstatus_parse_from_string(const char *s);
void authority_cert_free(authority_cert_t *cert);
authority_cert_t *authority_cert_parse_from_string(const char *s,
char **end_of_string);
#endif

259
src/or/routerparse.c
View File

@ -59,6 +59,19 @@ typedef enum {
K_EXTRA_INFO,
K_EXTRA_INFO_DIGEST,
K_CACHES_EXTRA_INFO,
K_DIR_KEY_CERTIFICATE_VERSION,
K_DIR_IDENTITY_KEY,
K_DIR_KEY_PUBLISHED,
K_DIR_KEY_EXPIRES,
K_DIR_KEY_CERTIFICATION,
K_VOTE_STATUS,
K_VALID_UNTIL,
K_KNOWN_FLAGS,
K_VOTE_DIGEST,
K_CONSENSUS_DIGEST,
_UNRECOGNIZED,
_ERR,
_EOF,
@ -91,6 +104,7 @@ typedef struct directory_token_t {
typedef enum {
NO_OBJ, /**< No object, ever. */
NEED_OBJ, /**< Object is required. */
NEED_KEY_1024, /**< Object is required, and must be a public key of 1024 bits */
NEED_KEY, /**< Object is required, and must be a public key. */
OBJ_OK, /**< Object is optional. */
} obj_syntax;
@ -108,6 +122,7 @@ typedef struct token_rule_t {
#define T(s,t,a,o) { s, t, a, o, 0, INT_MAX }
#define T0N(s,t,a,o) { s, t, a, o, 0, INT_MAX }
#define T1(s,t,a,o) { s, t, a, o, 1, 1 }
#define T1N(s,t,a,o) { s, t, a, o, 1, INT_MAX }
#define T01(s,t,a,o) { s, t, a, o, 0, 1 }
#define ARGS 0,INT_MAX,0
@ -121,8 +136,8 @@ static token_rule_t routerdesc_token_table[] = {
T0N("accept", K_ACCEPT, ARGS, NO_OBJ ),
T0N("reject", K_REJECT, ARGS, NO_OBJ ),
T1( "router", K_ROUTER, GE(5), NO_OBJ ),
T1( "signing-key", K_SIGNING_KEY, NO_ARGS, NEED_KEY ),
T1( "onion-key", K_ONION_KEY, NO_ARGS, NEED_KEY ),
T1( "signing-key", K_SIGNING_KEY, NO_ARGS, NEED_KEY_1024 ),
T1( "onion-key", K_ONION_KEY, NO_ARGS, NEED_KEY_1024 ),
T1( "router-signature", K_ROUTER_SIGNATURE, NO_ARGS, NEED_OBJ ),
T1( "published", K_PUBLISHED, CONCAT_ARGS, NO_OBJ ),
T0N("opt", K_OPT, CONCAT_ARGS, OBJ_OK ),
@ -166,7 +181,7 @@ static token_rule_t netstatus_token_table[] = {
T0N("opt", K_OPT, CONCAT_ARGS, OBJ_OK ),
T1( "contact", K_CONTACT, CONCAT_ARGS, NO_OBJ ),
/* XXXX should dir-signing-key really have ARGS? */
T1( "dir-signing-key", K_DIR_SIGNING_KEY, ARGS, NEED_KEY ),
T1( "dir-signing-key", K_DIR_SIGNING_KEY, ARGS, NEED_KEY_1024 ),
T1( "fingerprint", K_FINGERPRINT, CONCAT_ARGS, NO_OBJ ),
T1( "network-status-version", K_NETWORK_STATUS_VERSION,
GE(1), NO_OBJ ),
@ -201,6 +216,82 @@ static token_rule_t dir_token_table[] = {
END_OF_TABLE
};
#define CERTIFICATE_MEMBERS \
T1("dir-key-certificate-version", K_DIR_KEY_CERTIFICATE_VERSION, \
GE(1), NO_OBJ ), \
T1("dir-identity-key", K_DIR_IDENTITY_KEY, NO_ARGS, NEED_KEY ),\
T1("dir-key-published",K_DIR_KEY_PUBLISHED, CONCAT_ARGS, NO_OBJ), \
T1("dir-key-expires", K_DIR_KEY_EXPIRES, CONCAT_ARGS, NO_OBJ), \
T1("dir-signing-key", K_DIR_SIGNING_KEY, NO_ARGS, NEED_KEY ),\
T1("dir-key-certification", K_DIR_KEY_CERTIFICATION, \
NO_ARGS, NEED_OBJ),
static token_rule_t dir_key_certificate_table[] = {
CERTIFICATE_MEMBERS
T1("fingerprint", K_FINGERPRINT, CONCAT_ARGS, NO_OBJ ),
END_OF_TABLE
};
#if 0
/* XXXX This stuff is commented out for now so we can avoid warnings about
* unused variables. */
static token_rule_t status_vote_table[] = {
T1("network-status-version", K_NETWORK_STATUS_VERSION,
GE(1), NO_OBJ ),
T1("vote-status", K_VOTE_STATUS, GE(1), NO_OBJ ),
T1("published", K_PUBLISHED, CONCAT_ARGS, NO_OBJ ),
T1("valid-until", K_VALID_UNTIL, CONCAT_ARGS, NO_OBJ ),
T1("known-flags", K_KNOWN_FLAGS, CONCAT_ARGS, NO_OBJ ),
T( "fingerprint", K_FINGERPRINT, CONCAT_ARGS, NO_OBJ ),
CERTIFICATE_MEMBERS
T0N("opt", K_OPT, CONCAT_ARGS, OBJ_OK ),
T1( "contact", K_CONTACT, CONCAT_ARGS, NO_OBJ ),
T1( "dir-source", K_DIR_SOURCE, GE(3), NO_OBJ ),
T1( "dir-options", K_DIR_OPTIONS, ARGS, NO_OBJ ),
T1( "known-flags", K_KNOWN_FLAGS, CONCAT_ARGS, NO_OBJ ),
T01("client-versions", K_CLIENT_VERSIONS, CONCAT_ARGS, NO_OBJ ),
T01("server-versions", K_SERVER_VERSIONS, CONCAT_ARGS, NO_OBJ ),
END_OF_TABLE
};
static token_rule_t status_consensus_table[] = {
T1("network-status-version", K_NETWORK_STATUS_VERSION,
GE(1), NO_OBJ ),
T1("vote-status", K_VOTE_STATUS, GE(1), NO_OBJ ),
T1("published", K_PUBLISHED, CONCAT_ARGS, NO_OBJ ),
T1("valid-until", K_VALID_UNTIL, CONCAT_ARGS, NO_OBJ ),
CERTIFICATE_MEMBERS
T0N("opt", K_OPT, CONCAT_ARGS, OBJ_OK ),
T1N("dir-source", K_DIR_SOURCE, GE(3), NO_OBJ ),
T1N("fingerprint", K_FINGERPRINT, CONCAT_ARGS, NO_OBJ ),
T1N("contact", K_CONTACT, CONCAT_ARGS, NO_OBJ ),
T1N("vote-digest", K_VOTE_DIGEST, GE(1), NO_OBJ ),
#if 0
T1( "dir-options", K_DIR_OPTIONS, ARGS, NO_OBJ ),
T1( "known-flags", K_KNOWN_FLAGS, CONCAT_ARGS, NO_OBJ ),
#endif
T01("client-versions", K_CLIENT_VERSIONS, CONCAT_ARGS, NO_OBJ ),
T01("server-versions", K_SERVER_VERSIONS, CONCAT_ARGS, NO_OBJ ),
END_OF_TABLE
};
static token_rule_t vote_footer_token_table[] = {
T01("consensus-digest", K_CONSENSUS_DIGEST, EQ(1), NO_OBJ ),
T( "directory-signature", K_DIRECTORY_SIGNATURE, GE(2), NEED_OBJ ),
END_OF_TABLE
};
#endif
#undef T
/* static function prototypes */
@ -285,13 +376,14 @@ int
router_append_dirobj_signature(char *buf, size_t buf_len, const char *digest,
crypto_pk_env_t *private_key)
{
char signature[PK_BYTES];
char *signature;
int i;
signature = tor_malloc(crypto_pk_keysize(private_key));
if (crypto_pk_private_sign(private_key, signature, digest, DIGEST_LEN) < 0) {
log_warn(LD_BUG,"Couldn't sign digest.");
return -1;
goto err;
}
if (strlcat(buf, "-----BEGIN SIGNATURE-----\n", buf_len) >= buf_len)
goto truncated;
@ -300,15 +392,19 @@ router_append_dirobj_signature(char *buf, size_t buf_len, const char *digest,
if (base64_encode(buf+i, buf_len-i, signature, 128) < 0) {
log_warn(LD_BUG,"couldn't base64-encode signature");
tor_free(buf);
return -1;
goto err;
}
if (strlcat(buf, "-----END SIGNATURE-----\n", buf_len) >= buf_len)
goto truncated;
tor_free(signature);
return 0;
truncated:
log_warn(LD_BUG,"tried to exceed string length.");
err:
tor_free(signature);
return -1;
}
@ -623,7 +719,7 @@ dir_signing_key_is_trusted(crypto_pk_env_t *key)
}
/** Check whether the K_DIRECTORY_SIGNATURE token in <b>tok</b> has a
* good signature for <b>digest</b>.
* good signature for <b>digest</b>. DOCDOC can be another type.
*
* If <b>declared_key</b> is set, the directory has declared what key
* was used to sign it, so we will use that key only if it is an
@ -641,11 +737,9 @@ check_directory_signature(const char *digest,
crypto_pk_env_t *declared_key,
int check_authority)
{
char signed_digest[PK_BYTES];
char *signed_digest;
crypto_pk_env_t *_pkey = NULL;
tor_assert(tok->n_args == 1);
if (declared_key) {
if (!check_authority || dir_signing_key_is_trusted(declared_key))
_pkey = declared_key;
@ -661,14 +755,15 @@ check_directory_signature(const char *digest,
return -1;
}
if (strcmp(tok->object_type, "SIGNATURE") || tok->object_size != 128) {
log_warn(LD_DIR, "Bad object type or length on directory signature");
if (strcmp(tok->object_type, "SIGNATURE")) {
log_warn(LD_DIR, "Bad object type on directory signature");
return -1;
}
tor_assert(_pkey);
if (crypto_pk_public_checksig(_pkey, signed_digest, tok->object_body, 128)
signed_digest = tor_malloc(tok->object_size);
if (crypto_pk_public_checksig(_pkey, signed_digest, tok->object_body,
tok->object_size)
!= 20) {
log_warn(LD_DIR, "Error reading directory: invalid signature.");
return -1;
@ -912,21 +1007,11 @@ router_parse_entry_from_string(const char *s, const char *end,
tok = find_first_by_keyword(tokens, K_ONION_KEY);
tor_assert(tok);
if (crypto_pk_keysize(tok->key) != PK_BYTES) {
log_warn(LD_DIR, "Wrong size on onion key: %d bits!",
(int)crypto_pk_keysize(tok->key)*8);
goto err;
}
router->onion_pkey = tok->key;
tok->key = NULL; /* Prevent free */
tok = find_first_by_keyword(tokens, K_SIGNING_KEY);
tor_assert(tok);
if (crypto_pk_keysize(tok->key) != PK_BYTES) {
log_warn(LD_DIR, "Wrong size on identity key: %d bits!",
(int)crypto_pk_keysize(tok->key)*8);
goto err;
}
router->identity_pkey = tok->key;
tok->key = NULL; /* Prevent free */
if (crypto_pk_get_digest(router->identity_pkey,
@ -1157,6 +1242,124 @@ extrainfo_parse_entry_from_string(const char *s, const char *end,
return extrainfo;
}
/** DOCDOC */
void
authority_cert_free(authority_cert_t *cert)
{
if (!cert)
return;
tor_free(cert->cache_info.signed_descriptor_body);
if (cert->signing_key)
crypto_free_pk_env(cert->signing_key);
if (cert->identity_key)
crypto_free_pk_env(cert->identity_key);
tor_free(cert);
}
/** DOCDOC */
authority_cert_t *
authority_cert_parse_from_string(const char *s, char **end_of_string)
{
authority_cert_t *cert = NULL;
smartlist_t *tokens = NULL;
char digest[DIGEST_LEN];
directory_token_t *tok;
char fp_declared[DIGEST_LEN];
char *eos = strstr(s, "\n-----END SIGNATURE-----\n");
size_t len;
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;
tokens = smartlist_create();
if (tokenize_string(s, eos, tokens, dir_key_certificate_table) < 0) {
log_warn(LD_DIR, "Error tokenizing key certificate");
goto err;
}
if (router_get_hash_impl(s, digest, "dir-key-certificate-version",
"\ndir-key-certification") < 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));
tok = find_first_by_keyword(tokens, K_DIR_SIGNING_KEY);
tor_assert(tok && tok->key);
cert->signing_key = tok->key;
tok->key = NULL;
tok = find_first_by_keyword(tokens, K_DIR_IDENTITY_KEY);
tor_assert(tok && tok->key);
cert->identity_key = tok->key;
tok->key = NULL;
tok = find_first_by_keyword(tokens, K_FINGERPRINT);
tor_assert(tok && tok->n_args);
if (base16_decode(fp_declared, DIGEST_LEN, tok->args[0],
strlen(tok->args[0]))) {
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 (memcmp(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_first_by_keyword(tokens, K_DIR_KEY_PUBLISHED);
tor_assert(tok);
if (parse_iso_time(tok->args[0], &cert->cache_info.published_on) < 0) {
goto err;
}
tok = find_first_by_keyword(tokens, K_DIR_KEY_EXPIRES);
tor_assert(tok);
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;
}
/* XXXXX This doesn't check whether the key is an authority. IS that what we
* want? */
if (check_directory_signature(digest, tok, NULL, cert->identity_key, 0)) {
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;
*end_of_string = eos;
return cert;
err:
authority_cert_free(cert);
return NULL;
}
/** Helper: given a string <b>s</b>, return the start of the next router-status
* object (starting with "r " at the start of a line). If none is found,
* return the start of the next directory signature. If none is found, return
@ -1841,10 +2044,16 @@ get_next_token(const char **s, struct token_rule_t *table)
RET_ERR(ebuf);
}
break;
case NEED_KEY_1024:
if (tok->key && crypto_pk_keysize(tok->key) != PK_BYTES) {
tor_snprintf(ebuf, sizeof(ebuf), "Wrong size on key for %s: %d bits",
kwd, (int)crypto_pk_keysize(tok->key));
RET_ERR(ebuf);
}
/* fall through */
case NEED_KEY:
if (!tok->key) {
tor_snprintf(ebuf, sizeof(ebuf), "Missing public key for %s", kwd);
RET_ERR(ebuf);
}
break;
case OBJ_OK: