From: Alexander Færøy <ahf@torproject.org>
Date: Sat, 15 Sep 2018 20:17:57 +0000 (+0200)
Subject: Add proxy headers as early as possible.
X-Git-Tag: tor-0.3.5.3-alpha~55^2~2
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=3477a73af99eb72f8374928fdc2fab4858485219;p=thirdparty%2Ftor.git

Add proxy headers as early as possible.

This patch moves the logic that adds the proxy headers to an earlier
point in the exit connection lifetime, which ensures that the
application data cannot be written to the outbuf before the proxy header
is added.

See: https://bugs.torproject.org/4700
---

diff --git a/src/core/or/connection_edge.c b/src/core/or/connection_edge.c
index 0eff007e36..ab2acaa39c 100644
--- a/src/core/or/connection_edge.c
+++ b/src/core/or/connection_edge.c
@@ -600,8 +600,7 @@ connected_cell_format_payload(uint8_t *payload_out,
 /* This is an onion service client connection: Export the client circuit ID
  * according to the HAProxy proxy protocol. */
 STATIC void
-export_hs_client_circuit_id(const edge_connection_t *edge_conn,
-                            connection_t *conn,
+export_hs_client_circuit_id(edge_connection_t *edge_conn,
                             hs_circuit_id_protocol_t protocol)
 {
   /* We only support HAProxy right now. */
@@ -633,7 +632,7 @@ export_hs_client_circuit_id(const edge_connection_t *edge_conn,
                gid >> 16, gid & 0x0000ffff,
                dst_ipv6, src_port, dst_port);
 
-  connection_buf_add(buf, strlen(buf), conn);
+  connection_buf_add(buf, strlen(buf), TO_CONN(edge_conn));
 
   tor_free(buf);
 }
@@ -659,14 +658,6 @@ connection_edge_finished_connecting(edge_connection_t *edge_conn)
 
   conn->state = EXIT_CONN_STATE_OPEN;
 
-  /* If it's an onion service connection, we might want to include the proxy
-   * protocol header: */
-  if (edge_conn->hs_ident) {
-    hs_circuit_id_protocol_t circuit_id_protocol =
-      hs_service_exports_circuit_id(&edge_conn->hs_ident->identity_pk);
-    export_hs_client_circuit_id(edge_conn, conn, circuit_id_protocol);
-  }
-
   connection_watch_events(conn, READ_EVENT); /* stop writing, keep reading */
   if (connection_get_outbuf_len(conn)) /* in case there are any queued relay
                                         * cells */
@@ -3452,6 +3443,14 @@ handle_hs_exit_conn(circuit_t *circ, edge_connection_t *conn)
 
   hs_inc_rdv_stream_counter(origin_circ);
 
+  /* If it's an onion service connection, we might want to include the proxy
+   * protocol header: */
+  if (conn->hs_ident) {
+    hs_circuit_id_protocol_t circuit_id_protocol =
+      hs_service_exports_circuit_id(&conn->hs_ident->identity_pk);
+    export_hs_client_circuit_id(conn, circuit_id_protocol);
+  }
+
   /* Connect tor to the hidden service destination. */
   connection_exit_connect(conn);
 
diff --git a/src/core/or/connection_edge.h b/src/core/or/connection_edge.h
index c5ad3128a2..5b694428de 100644
--- a/src/core/or/connection_edge.h
+++ b/src/core/or/connection_edge.h
@@ -246,8 +246,7 @@ STATIC void connection_ap_handshake_rewrite(entry_connection_t *conn,
 
 STATIC int connection_ap_process_http_connect(entry_connection_t *conn);
 STATIC void
-export_hs_client_circuit_id(const edge_connection_t *edge_conn,
-                            connection_t *conn,
+export_hs_client_circuit_id(edge_connection_t *edge_conn,
                             hs_circuit_id_protocol_t protocol);
 
 #endif /* defined(CONNECTION_EDGE_PRIVATE) */
diff --git a/src/test/test_hs_service.c b/src/test/test_hs_service.c
index 955bcc8aff..dace2b63d8 100644
--- a/src/test/test_hs_service.c
+++ b/src/test/test_hs_service.c
@@ -2047,8 +2047,7 @@ test_export_client_circuit_id(void *arg)
   or_circ->global_identifier = 666;
 
   /* Export circuit ID */
-  export_hs_client_circuit_id(edge_conn, conn,
-                              service->config.circuit_id_protocol);
+  export_hs_client_circuit_id(edge_conn, service->config.circuit_id_protocol);
 
   /* Check contents */
   cp1 = buf_get_contents(conn->outbuf, &sz);
@@ -2059,8 +2058,7 @@ test_export_client_circuit_id(void *arg)
   or_circ->global_identifier = 22;
 
   /* check changes */
-  export_hs_client_circuit_id(edge_conn, conn,
-                              service->config.circuit_id_protocol);
+  export_hs_client_circuit_id(edge_conn, service->config.circuit_id_protocol);
   cp2 = buf_get_contents(conn->outbuf, &sz);
   tt_str_op(cp1, OP_NE, cp2);
   tor_free(cp1);
@@ -2068,8 +2066,7 @@ test_export_client_circuit_id(void *arg)
   /* Check that GID with UINT32_MAX works. */
   or_circ->global_identifier = UINT32_MAX;
 
-  export_hs_client_circuit_id(edge_conn, conn,
-                              service->config.circuit_id_protocol);
+  export_hs_client_circuit_id(edge_conn, service->config.circuit_id_protocol);
   cp1 = buf_get_contents(conn->outbuf, &sz);
   tt_str_op(cp1, OP_EQ,
             "PROXY TCP6 fc00:dead:beef:4dad::ffff:ffff ::1 65535 42\r\n");
@@ -2078,8 +2075,7 @@ test_export_client_circuit_id(void *arg)
   /* Check that GID with UINT16_MAX works. */
   or_circ->global_identifier = UINT16_MAX;
 
-  export_hs_client_circuit_id(edge_conn, conn,
-                              service->config.circuit_id_protocol);
+  export_hs_client_circuit_id(edge_conn, service->config.circuit_id_protocol);
   cp1 = buf_get_contents(conn->outbuf, &sz);
   tt_str_op(cp1, OP_EQ,
             "PROXY TCP6 fc00:dead:beef:4dad::0:ffff ::1 65535 42\r\n");
@@ -2088,8 +2084,7 @@ test_export_client_circuit_id(void *arg)
   /* Check that GID with UINT16_MAX + 7 works. */
   or_circ->global_identifier = UINT16_MAX + 7;
 
-  export_hs_client_circuit_id(edge_conn, conn,
-                              service->config.circuit_id_protocol);
+  export_hs_client_circuit_id(edge_conn, service->config.circuit_id_protocol);
   cp1 = buf_get_contents(conn->outbuf, &sz);
   tt_str_op(cp1, OP_EQ, "PROXY TCP6 fc00:dead:beef:4dad::1:6 ::1 6 42\r\n");