commit ce3af5dd5948cd9c24fc5b5f70814b38cbca46a9 Author: David Goulet dgoulet@torproject.org Date: Mon Feb 1 08:56:27 2021 -0500

relay: Follow consensus parameter for network reentry

Obey the "allow-network-reentry" consensus parameters in order to decide to allow it or not at the Exit.

Closes #40268

Signed-off-by: David Goulet dgoulet@torproject.org --- src/core/or/connection_edge.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)

diff --git a/src/core/or/connection_edge.c b/src/core/or/connection_edge.c index f9a9bbdb73..b40fa3e567 100644 --- a/src/core/or/connection_edge.c +++ b/src/core/or/connection_edge.c @@ -4003,6 +4003,15 @@ my_exit_policy_rejects(const tor_addr_t *addr, return 0; }

+/** Return true iff the consensus allows network reentry. The default value is + * false if the parameter is not found. */ +static bool +network_reentry_is_allowed(void) +{ + /* Default is false, re-entry is not allowed. */ + return !!networkstatus_get_param(NULL, "allow-network-reentry", 0, 0, 1); +} + /** Connect to conn's specified addr and port. If it worked, conn * has now been added to the connection_array. * @@ -4040,6 +4049,8 @@ connection_exit_connect(edge_connection_t *edge_conn) * infinite-length circuits (see "A Practical Congestion Attack on Tor Using * Long Paths", Usenix Security 2009). See also ticket 2667. * + * Skip this if the network reentry is allowed (known from the consensus). + * * The TORPROTOCOL reason is used instead of EXITPOLICY so client do NOT * attempt to retry connecting onto another circuit that will also fail * bringing considerable more load on the network if so. @@ -4050,6 +4061,7 @@ connection_exit_connect(edge_connection_t *edge_conn) * reason that makes the client retry results in much worst consequences in * case of an attack so this is a small price to pay. */ if (!connection_edge_is_rendezvous_stream(edge_conn) && + !network_reentry_is_allowed() && nodelist_reentry_probably_contains(&conn->addr, conn->port)) { log_info(LD_EXIT, "%s:%d tried to connect back to a known relay address. " "Closing.", escaped_safe_str_client(conn->address),