r11773@catbus: nickm | 2007-02-12 15:18:48 -0500
Implement proposal 106: stop requiring clients to have certificates, and stop checking for nicknames in certificates. [See proposal 106 for rationale.] Also improve messages when checking TLS handshake, to re-resolve bug 382. svn:r9568
This commit is contained in:
Nick Mathewson
parent
3af0d90a7a
commit
0c40a080a4
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@ -33,6 +33,14 @@ Changes in version 0.1.2.8-alpha - 2007-??-??
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advance warning.
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- Remove some never-implemented options. Mark PathlenCoinWeight as
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obsolete.
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- Implement proposal 106: Stop requiring clients to have well-formed
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certificates; stop checking nicknames in certificates. (Clients have
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certificates so that they can look like Tor servers, but in the future
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we might want to allow them to look like regular TLS clients instead.
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Nicknames in certificates serve no purpose other than making our
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protocol easier to recognize on the wire.)
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- Revise messages on handshake failure again to be even more clear about
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which are incoming connections and which are outgoing.
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Changes in version 0.1.2.7-alpha - 2007-02-06
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16
doc/TODO
16
doc/TODO
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@ -111,12 +111,14 @@ NR. Write path-spec.txt
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- recommend gaim.
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- unrecommend IE because of ftp:// bug.
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N - we should add a preamble to tor-design saying it's out of date.
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N - Document transport and natdport
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N . Document transport and natdport
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o In man page
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- In a good HOWTO.
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- Forward compatibility fixes
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- Caches should start trying to cache consensus docs?
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NR - Design
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N - Implement, if we think it's smart.
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. Forward compatibility fixes
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D Caches should start trying to cache consensus docs?
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D Design
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D Implement, if we think it's smart.
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- Start uploading short and long descriptors; authorities should support
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URLs to retrieve long descriptors, and should discard short descriptors
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for now. Later, once tools use the "long descriptor" URLs, authorities
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@ -124,9 +126,11 @@ N - Implement, if we think it's smart.
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a descriptor.
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NR - Design
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N - Implement, if we think it's smart.
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- Check for any outstanding checks we do on the form or number of client
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o Check for any outstanding checks we do on the form or number of client
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certificates that would prevent us from executing certain
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blocking-resistance strategies.
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o Design (proposal 106)
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o Implement
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Things we'd like to do in 0.2.0:
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- Proposals:
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@ -24,5 +24,5 @@ Proposals by number:
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103 Splitting identity key from regularly used signing key [OPEN]
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104 Long and Short Router Descriptors [OPEN]
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105 Version negotiation for the Tor protocol [OPEN]
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106 Checking fewer things during TLS handshakes [OPEN]
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106 Checking fewer things during TLS handshakes [FINISHED]
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@ -4,7 +4,7 @@ Version: $Revision: 12105 $
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Last-Modified: $Date: 2007-01-30T07:50:01.643717Z $
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Author: Nick Mathewson
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Created:
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Status: Accepted
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Status: Finished
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Overview:
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@ -672,56 +672,6 @@ tor_tls_peer_has_cert(tor_tls_t *tls)
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return 1;
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}
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/** Write the nickname (if any) that the peer connected on <b>tls</b>
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* claims to have into the first <b>buflen</b> characters of <b>buf</b>.
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* Truncate the nickname if it is longer than buflen-1 characters. Always
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* NUL-terminate. Return 0 on success, -1 on failure.
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*/
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int
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tor_tls_get_peer_cert_nickname(int severity, tor_tls_t *tls,
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char *buf, size_t buflen)
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{
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X509 *cert = NULL;
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X509_NAME *name = NULL;
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int nid;
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int lenout;
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int r = -1;
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if (!(cert = SSL_get_peer_certificate(tls->ssl))) {
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log_fn(severity, LD_PROTOCOL, "Peer has no certificate");
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goto error;
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}
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if (!(name = X509_get_subject_name(cert))) {
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log_fn(severity, LD_PROTOCOL, "Peer certificate has no subject name");
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goto error;
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}
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if ((nid = OBJ_txt2nid("commonName")) == NID_undef)
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goto error;
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lenout = X509_NAME_get_text_by_NID(name, nid, buf, buflen);
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if (lenout == -1)
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goto error;
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if (((int)strspn(buf, LEGAL_NICKNAME_CHARACTERS)) < lenout) {
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log_fn(severity, LD_PROTOCOL,
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"Peer certificate nickname %s has illegal characters.",
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escaped(buf));
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if (strchr(buf, '.'))
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log_fn(severity, LD_PROTOCOL,
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" (Maybe it is not really running Tor at its "
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"advertised OR port.)");
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goto error;
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}
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r = 0;
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error:
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if (cert)
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X509_free(cert);
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tls_log_errors(severity, "getting peer certificate nickname");
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return r;
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}
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/** DOCDOC */
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static void
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log_cert_lifetime(X509 *cert, const char *problem)
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@ -70,6 +70,11 @@ get_unique_circ_id_by_conn(or_connection_t *conn)
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uint16_t high_bit;
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tor_assert(conn);
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if (conn->circ_id_type == CIRC_ID_TYPE_NEITHER) {
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log_warn(LD_BUG, "Bug: Trying to pick a circuit ID for a connection from "
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"a client with no identity.");
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return 0;
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}
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high_bit = (conn->circ_id_type == CIRC_ID_TYPE_HIGHER) ? 1<<15 : 0;
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do {
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/* Sequentially iterate over test_circ_id=1...1<<15-1 until we find a
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@ -26,7 +26,7 @@ static int connection_or_empty_enough_for_dirserv_data(or_connection_t *conn);
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static digestmap_t *orconn_identity_map = NULL;
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/** If conn is listed in orconn_identity_map, remove it, and clear
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* conn->identity_digest. */
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* conn->identity_digest. Otherwise do nothing. */
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void
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connection_or_remove_from_identity_map(or_connection_t *conn)
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{
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@ -35,8 +35,13 @@ connection_or_remove_from_identity_map(or_connection_t *conn)
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if (!orconn_identity_map)
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return;
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tmp = digestmap_get(orconn_identity_map, conn->identity_digest);
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if (!tmp)
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if (!tmp) {
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if (!tor_digest_is_zero(conn->identity_digest)) {
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log_warn(LD_BUG, "Didn't found connection on identity map when trying "
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"to remove it.");
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}
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return;
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}
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if (conn == tmp) {
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if (conn->next_with_same_id)
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digestmap_set(orconn_identity_map, conn->identity_digest,
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@ -81,7 +86,7 @@ connection_or_clear_identity_map(void)
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}
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/** Change conn->identity_digest to digest, and add conn into
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* orconn_digest_map. */
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* orconn_digest_map. */
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static void
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connection_or_set_identity_digest(or_connection_t *conn, const char *digest)
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{
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@ -93,14 +98,22 @@ connection_or_set_identity_digest(or_connection_t *conn, const char *digest)
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orconn_identity_map = digestmap_new();
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if (!memcmp(conn->identity_digest, digest, DIGEST_LEN))
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return;
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if (tor_digest_is_zero(conn->identity_digest))
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/* If the identity was set previously, remove the old mapping. */
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if (! tor_digest_is_zero(conn->identity_digest))
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connection_or_remove_from_identity_map(conn);
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memcpy(conn->identity_digest, digest, DIGEST_LEN);
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/* If we're setting the ID to zero, don't add a mapping.*/
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if (tor_digest_is_zero(digest))
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return;
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tmp = digestmap_set(orconn_identity_map, digest, conn);
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conn->next_with_same_id = tmp;
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#if 0
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#if 1
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/*XXXX012 change this back to if 0. */
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/* Testing code to check for bugs in representation. */
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for (; tmp; tmp = tmp->next_with_same_id) {
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tor_assert(!memcmp(tmp->identity_digest, digest, DIGEST_LEN));
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@ -551,16 +564,21 @@ connection_or_nonopen_was_started_here(or_connection_t *conn)
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return !tor_tls_is_server(conn->tls);
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}
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/** Conn just completed its handshake. Return 0 if all is well, and
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/** <b>Conn</b> just completed its handshake. Return 0 if all is well, and
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* return -1 if he is lying, broken, or otherwise something is wrong.
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*
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* Make sure he sent a correctly formed certificate. If it has a
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* recognized ("named") nickname, make sure his identity key matches
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* it. If I initiated the connection, make sure it's the right guy.
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* If we initiated this connection (<b>started_here</b> is true), make sure
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* the other side sent sent a correctly formed certificate. If I initiated the
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* connection, make sure it's the right guy.
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*
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* If we return 0, write a hash of the identity key into digest_rcvd,
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* which must have DIGEST_LEN space in it. (If we return -1 this
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* buffer is undefined.)
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* Otherwise (if we _didn't_ initiate this connection), it's okay for
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* the certificate to be weird or absent.
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*
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* If we return 0, and the certificate is as expected, write a hash of the
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* identity key into digest_rcvd, which must have DIGEST_LEN space in it. (If
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* we return -1 this buffer is undefined.) If the certificate is invalid
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* or missing on an incoming connection, we return 0 and set digest_rcvd to
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* DIGEST_LEN 0 bytes.
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*
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* As side effects,
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* 1) Set conn->circ_id_type according to tor-spec.txt.
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@ -569,66 +587,68 @@ connection_or_nonopen_was_started_here(or_connection_t *conn)
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* this guy; and note that this guy is reachable.
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*/
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static int
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connection_or_check_valid_handshake(or_connection_t *conn, char *digest_rcvd)
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connection_or_check_valid_handshake(or_connection_t *conn, int started_here,
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char *digest_rcvd)
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{
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routerinfo_t *router;
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crypto_pk_env_t *identity_rcvd=NULL;
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char nickname[MAX_NICKNAME_LEN+1];
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or_options_t *options = get_options();
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int severity = server_mode(options) ? LOG_PROTOCOL_WARN : LOG_WARN;
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int started_here = connection_or_nonopen_was_started_here(conn);
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const char *safe_address =
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started_here ? conn->_base.address : safe_str(conn->_base.address);
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const char *peer_type = started_here ? "Router" : "Client or router";
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const char *conn_type = started_here ? "outgoing" : "incoming";
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int has_cert = 0, has_identity = 0;
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check_no_tls_errors();
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if (! tor_tls_peer_has_cert(conn->tls)) {
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log_info(LD_PROTOCOL,"%s (%s:%d) didn't send a cert! Closing.",
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peer_type, safe_address, conn->_base.port);
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has_cert = tor_tls_peer_has_cert(conn->tls);
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if (started_here && !has_cert) {
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log_info(LD_PROTOCOL,"Tried connecting to router at %s:%d, but it didn't "
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"send a cert! Closing.",
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safe_address, conn->_base.port);
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return -1;
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} else if (!has_cert) {
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log_debug(LD_PROTOCOL,"Got incoming connection with no certificate. "
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"That's ok.");
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}
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check_no_tls_errors();
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if (tor_tls_get_peer_cert_nickname(severity, conn->tls, nickname,
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sizeof(nickname))) {
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log_fn(severity,LD_PROTOCOL,"%s (%s:%d) has a cert without a "
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"valid nickname. Closing.",
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peer_type, safe_address, conn->_base.port);
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return -1;
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}
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check_no_tls_errors();
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log_debug(LD_OR, "%s (%s:%d) claims to be router '%s'",
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peer_type, safe_address, conn->_base.port, nickname);
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if (tor_tls_verify(severity, conn->tls, &identity_rcvd) < 0) {
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log_fn(severity,LD_OR,"%s which claims to be router '%s' (%s:%d),"
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" has a cert but it's invalid. Closing.",
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peer_type, nickname, safe_address, conn->_base.port);
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return -1;
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if (has_cert) {
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int v = tor_tls_verify(started_here?severity:LOG_INFO,
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conn->tls, &identity_rcvd);
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if (started_here && v<0) {
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log_fn(severity,LD_OR,"Tried connecting to router at %s:%d: It"
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" has a cert but it's invalid. Closing.",
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safe_address, conn->_base.port);
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return -1;
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} else if (v<0) {
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log_info(LD_PROTOCOL,"Incoming connection gave us an invalid cert "
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"chain; ignoring.");
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} else {
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log_debug(LD_OR,"The certificate seems to be valid on %s connection "
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"with %s:%d", conn_type, safe_address, conn->_base.port);
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}
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check_no_tls_errors();
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}
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check_no_tls_errors();
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log_debug(LD_OR,"The router's cert is valid.");
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crypto_pk_get_digest(identity_rcvd, digest_rcvd);
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if (crypto_pk_cmp_keys(get_identity_key(), identity_rcvd)<0) {
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conn->circ_id_type = CIRC_ID_TYPE_LOWER;
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if (identity_rcvd) {
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has_identity=1;
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crypto_pk_get_digest(identity_rcvd, digest_rcvd);
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if (crypto_pk_cmp_keys(get_identity_key(), identity_rcvd)<0) {
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conn->circ_id_type = CIRC_ID_TYPE_LOWER;
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} else {
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conn->circ_id_type = CIRC_ID_TYPE_HIGHER;
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}
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crypto_free_pk_env(identity_rcvd);
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} else {
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conn->circ_id_type = CIRC_ID_TYPE_HIGHER;
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}
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crypto_free_pk_env(identity_rcvd);
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router = router_get_by_nickname(nickname, 0);
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if (router && /* we know this nickname */
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router->is_named && /* make sure it's the right guy */
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memcmp(digest_rcvd, router->cache_info.identity_digest,DIGEST_LEN) !=0) {
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log_fn(severity, LD_OR,
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"Identity key not as expected for peer claiming to be "
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"'%s' (%s:%d)",
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nickname, safe_address, conn->_base.port);
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return -1;
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memset(digest_rcvd, 0, DIGEST_LEN);
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conn->circ_id_type = CIRC_ID_TYPE_NEITHER;
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}
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if (started_here) {
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int as_advertised = 1;
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tor_assert(has_cert);
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tor_assert(has_identity);
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if (memcmp(digest_rcvd, conn->identity_digest, DIGEST_LEN)) {
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/* I was aiming for a particular digest. I didn't get it! */
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char seen[HEX_DIGEST_LEN+1];
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@ -637,8 +657,8 @@ connection_or_check_valid_handshake(or_connection_t *conn, char *digest_rcvd)
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base16_encode(expected, sizeof(expected), conn->identity_digest,
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DIGEST_LEN);
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log_fn(severity, LD_OR,
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"Identity key not as expected for router at %s:%d: wanted %s "
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"but got %s",
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"Tried connecting to router at %s:%d, but identity key was not "
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"as expected wanted %s but got %s",
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conn->_base.address, conn->_base.port, expected, seen);
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entry_guard_register_connect_status(conn->identity_digest,0,time(NULL));
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router_set_status(conn->identity_digest, 0);
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@ -677,7 +697,7 @@ connection_tls_finish_handshake(or_connection_t *conn)
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int started_here = connection_or_nonopen_was_started_here(conn);
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log_debug(LD_OR,"tls handshake done. verifying.");
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if (connection_or_check_valid_handshake(conn, digest_rcvd) < 0)
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if (connection_or_check_valid_handshake(conn, started_here, digest_rcvd) < 0)
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return -1;
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if (!started_here) {
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14
src/or/or.h
14
src/or/or.h
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@ -201,7 +201,8 @@
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/** DOCDOC */
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typedef enum {
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CIRC_ID_TYPE_LOWER=0,
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CIRC_ID_TYPE_HIGHER=1
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CIRC_ID_TYPE_HIGHER=1,
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CIRC_ID_TYPE_NEITHER=2
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} circ_id_type_t;
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#define _CONN_TYPE_MIN 3
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@ -772,8 +773,9 @@ typedef struct connection_t {
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typedef struct or_connection_t {
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connection_t _base;
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char identity_digest[DIGEST_LEN]; /**< Hash of the public RSA key for
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* the other side's signing key. */
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/** Hash of the public RSA key for the other side's identity key, or zero if
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* the other side hasn't shown us a valid identity key. */
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char identity_digest[DIGEST_LEN];
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char *nickname; /**< Nickname of OR on other side (if any). */
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tor_tls_t *tls; /**< TLS connection state */
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@ -787,9 +789,6 @@ typedef struct or_connection_t {
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int read_bucket; /**< When this hits 0, stop receiving. Every second we
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* add 'bandwidthrate' to this, capping it at
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* bandwidthburst. (OPEN ORs only) */
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circ_id_type_t circ_id_type; /**< When we send CREATE cells along this
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* connection, which half of the space should
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* we use? */
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int n_circuits; /**< How many circuits use this connection as p_conn or
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* n_conn ? */
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struct or_connection_t *next_with_same_id; /**< Next connection with same
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@ -797,6 +796,9 @@ typedef struct or_connection_t {
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/** Linked list of bridged dirserver connections that can't write until
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* this connection's outbuf is less full. */
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struct dir_connection_t *blocked_dir_connections;
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circ_id_type_t circ_id_type:2; /**< When we send CREATE cells along this
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* connection, which half of the space should
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* we use? */
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uint16_t next_circ_id; /**< Which circ_id do we try to use next on
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* this connection? This is always in the
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* range 0..1<<15-1. */
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