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Our logic to decide if the OR we connected to was the right guy

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was brittle and maybe open to a mitm for unverified routers.

Now we be sure to check the digest, and if the nickname he claims is
not a verified one then we don't care what nickname he claims.


svn:r4823
This commit is contained in:
Roger Dingledine 2005-08-23 09:50:51 +00:00
parent 0a45058d0d
commit f35ef825f9
1 changed files with 17 additions and 23 deletions
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34
src/or/connection_or.c
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@ -232,7 +232,9 @@ connection_or_init_conn_from_router(connection_t *conn, routerinfo_t *router)
conn->address = tor_strdup(router->address); conn->address = tor_strdup(router->address);
} }
/** DOCDOC */ /** If we don't necessarily know the router we're connecting to, but we
* have an addr/port/id_digest, then fill in as much as we can. Start
* by checking to see if this describes a router we know. */
static void static void
connection_or_init_conn_from_address(connection_t *conn, connection_or_init_conn_from_address(connection_t *conn,
uint32_t addr, uint16_t port, uint32_t addr, uint16_t port,
@ -269,7 +271,8 @@ connection_or_init_conn_from_address(connection_t *conn,
tor_inet_ntoa(&in,conn->address,INET_NTOA_BUF_LEN); tor_inet_ntoa(&in,conn->address,INET_NTOA_BUF_LEN);
} }
/** DOCDOC */ /** "update an OR connection nickname on the fly"
* Actually, nobody calls this. Should we remove it? */
void void
connection_or_update_nickname(connection_t *conn) connection_or_update_nickname(connection_t *conn)
{ {
@ -308,7 +311,7 @@ connection_or_update_nickname(connection_t *conn)
* If <b>id_digest</b> is me, do nothing. If we're already connected to it, * If <b>id_digest</b> is me, do nothing. If we're already connected to it,
* return that connection. If the connect() is in progress, set the * return that connection. If the connect() is in progress, set the
* new conn's state to 'connecting' and return it. If connect() succeeds, * new conn's state to 'connecting' and return it. If connect() succeeds,
* call * connection_tls_start_handshake() on it. * call connection_tls_start_handshake() on it.
* *
* This function is called from router_retry_connections(), for * This function is called from router_retry_connections(), for
* ORs connecting to ORs, and circuit_establish_circuit(), for * ORs connecting to ORs, and circuit_establish_circuit(), for
@ -333,7 +336,6 @@ connection_or_connect(uint32_t addr, uint16_t port, const char *id_digest)
/* this function should never be called if we're already connected to /* this function should never be called if we're already connected to
* id_digest, but check first to be sure */ * id_digest, but check first to be sure */
/*XXX this is getting called, at least by dirservers. */
conn = connection_get_by_identity_digest(id_digest, CONN_TYPE_OR); conn = connection_get_by_identity_digest(id_digest, CONN_TYPE_OR);
if (conn) { if (conn) {
tor_assert(conn->nickname); tor_assert(conn->nickname);
@ -455,7 +457,7 @@ connection_or_nonopen_was_started_here(connection_t *conn)
* *
* Make sure he sent a correctly formed certificate. If it has a * Make sure he sent a correctly formed certificate. If it has a
* recognized (approved) nickname, make sure his identity key matches * recognized (approved) nickname, make sure his identity key matches
* to it. If I initiated the connection, make sure it's the right guy. * it. If I initiated the connection, make sure it's the right guy.
* *
* If we return 0, write a hash of the identity key into digest_rcvd, * If we return 0, write a hash of the identity key into digest_rcvd,
* which must have DIGEST_LEN space in it. (If we return -1 this * which must have DIGEST_LEN space in it. (If we return -1 this
@ -520,23 +522,15 @@ connection_or_check_valid_handshake(connection_t *conn, char *digest_rcvd)
if (connection_or_nonopen_was_started_here(conn)) { if (connection_or_nonopen_was_started_here(conn)) {
int as_advertised = 1; int as_advertised = 1;
if (conn->nickname[0] == '$') { if (memcmp(digest_rcvd, conn->identity_digest, DIGEST_LEN)) {
/* I was aiming for a particular digest. Did I get it? */ /* I was aiming for a particular digest. I didn't get it! */
char d[HEX_DIGEST_LEN+1]; char seen[HEX_DIGEST_LEN+1];
base16_encode(d, HEX_DIGEST_LEN+1, digest_rcvd, DIGEST_LEN); char expected[HEX_DIGEST_LEN+1];
if (strcasecmp(d,conn->nickname+1)) { base16_encode(seen, sizeof(seen), digest_rcvd, DIGEST_LEN);
base16_encode(expected, sizeof(expected), conn->identity_digest, DIGEST_LEN);
log_fn(severity, log_fn(severity,
"Identity key not as expected for router at %s:%d: wanted %s but got %s", "Identity key not as expected for router at %s:%d: wanted %s but got %s",
conn->address, conn->port, conn->nickname+1, d); conn->address, conn->port, expected, seen);
helper_node_set_status(conn->identity_digest, 0);
control_event_or_conn_status(conn, OR_CONN_EVENT_FAILED);
as_advertised = 0;
}
} else if (strcasecmp(conn->nickname, nickname)) {
/* I was aiming for a nickname. Did I get it? */
log_fn(severity,
"Other side (%s:%d) is '%s', but we tried to connect to '%s'",
conn->address, conn->port, nickname, conn->nickname);
helper_node_set_status(conn->identity_digest, 0); helper_node_set_status(conn->identity_digest, 0);
control_event_or_conn_status(conn, OR_CONN_EVENT_FAILED); control_event_or_conn_status(conn, OR_CONN_EVENT_FAILED);
as_advertised = 0; as_advertised = 0;