[tor-commits] [tor/maint-0.3.1] dos: Don't set consensus param if we aren't a public relay

[nickm at torproject.org]

commit 4fe4f8179fe81244319c7fdec64299b6506434a2
Author: David Goulet <dgoulet at torproject.org>
Date:   Tue Feb 13 10:29:41 2018 -0500

    dos: Don't set consensus param if we aren't a public relay
    
    We had this safeguard around dos_init() but not when the consensus changes
    which can modify consensus parameters and possibly enable the DoS mitigation
    even if tor wasn't a public relay.
    
    Fixes #25223
    
    Signed-off-by: David Goulet <dgoulet at torproject.org>
---
 changes/bug25223 | 3 +++
 src/or/dos.c     | 8 ++++++++
 2 files changed, 11 insertions(+)

diff --git a/changes/bug25223 b/changes/bug25223
new file mode 100644
index 000000000..2a7eb6b25
--- /dev/null
+++ b/changes/bug25223
@@ -0,0 +1,3 @@
+  o Minor bugfixes (DoS mitigation):
+    - Make sure we don't modify consensus parameters if we aren't a public
+      relay when a new consensus arrives. Fixes bug 25223.
diff --git a/src/or/dos.c b/src/or/dos.c
index 9e8a7a9ab..bfa415e7b 100644
--- a/src/or/dos.c
+++ b/src/or/dos.c
@@ -738,6 +738,14 @@ dos_close_client_conn(const or_connection_t *or_conn)
 void
 dos_consensus_has_changed(const networkstatus_t *ns)
 {
+  /* There are two ways to configure this subsystem, one at startup through
+   * dos_init() which is called when the options are parsed. And this one
+   * through the consensus. We don't want to enable any DoS mitigation if we
+   * aren't a public relay. */
+  if (!public_server_mode(get_options())) {
+    return;
+  }
+
   cc_consensus_has_changed(ns);
   conn_consensus_has_changed(ns);