From 64f393d56f8ff58223db56f3b8e64f0074877616 Mon Sep 17 00:00:00 2001 From: Roger Dingledine Date: Fri, 28 Aug 2009 03:42:09 -0400 Subject: [PATCH] Only send netinfo clock_skew to controller if an authority told us so We were triggering a CLOCK_SKEW controller status event whenever we connect via the v2 connection protocol to any relay that has a wrong clock. Instead, we should only inform the controller when it's a trusted authority that claims our clock is wrong. Bugfix on 0.2.0.20-rc; starts to fix bug 1074. Reported by SwissTorExit. --- ChangeLog | 5 +++++ doc/spec/control-spec.txt | 22 ++++++++++++++-------- src/or/command.c | 8 +++++--- 3 files changed, 24 insertions(+), 11 deletions(-) diff --git a/ChangeLog b/ChangeLog index 85c8321eb7..34ba6a7168 100644 --- a/ChangeLog +++ b/ChangeLog @@ -18,6 +18,11 @@ Changes in version 0.2.1.20 - 2009-??-?? - Fix an extremely rare infinite recursion bug that could occur if we tried to log a message after shutting down the log subsystem. Found by Matt Edman. Bugfix on 0.2.0.16-alpha. + - We were triggering a CLOCK_SKEW controller status event whenever + we connect via the v2 connection protocol to any relay that has + a wrong clock. Instead, we should only inform the controller when + it's a trusted authority that claims our clock is wrong. Bugfix + on 0.2.0.20-rc; starts to fix bug 1074. Reported by SwissTorExit. Changes in version 0.2.1.19 - 2009-07-28 diff --git a/doc/spec/control-spec.txt b/doc/spec/control-spec.txt index 576c5dcd53..0cc3bb2928 100644 --- a/doc/spec/control-spec.txt +++ b/doc/spec/control-spec.txt @@ -1255,20 +1255,26 @@ $Id$ CLOCK_SKEW SKEW="+" / "-" SECONDS MIN_SKEW="+" / "-" SECONDS. - SOURCE="DIRSERV:IP:Port" / "NETWORKSTATUS:IP:PORT" / "CONSENSUS" + SOURCE="DIRSERV:" IP ":" Port / + "NETWORKSTATUS:" IP ":" Port / + "OR:" IP ":" Port / + "CONSENSUS" If "SKEW" is present, it's an estimate of how far we are from the time declared in the source. (In other words, if we're an hour in the past, the value is -3600.) "MIN_SKEW" is present, it's a lower bound. If the source is a DIRSERV, we got the current time from a connection to a dirserver. If the source is a NETWORKSTATUS, we decided we're skewed because we got a v2 networkstatus from far in - the future. If the source is CONSENSUS, we decided we're skewed - because we got a networkstatus consensus from the future. - - {Controllers may want to warn the user if the skew is high, or if - multiple skew messages appear at severity WARN. Controllers - shouldn't blindly adjust the clock, since the more accurate source - of skew info (DIRSERV) is currently unauthenticated.} + the future. If the source is OR, the skew comes from a NETINFO + cell from a connection to another relay. If the source is + CONSENSUS, we decided we're skewed because we got a networkstatus + consensus from the future. + + {Tor should send this message to controllers when it thinks the + skew is so high that it will interfere with proper Tor operation. + Controllers shouldn't blindly adjust the clock, since the more + accurate source of skew info (DIRSERV) is currently + unauthenticated.} BAD_LIBEVENT "METHOD=" libevent method diff --git a/src/or/command.c b/src/or/command.c index c36874be5c..98f093a72b 100644 --- a/src/or/command.c +++ b/src/or/command.c @@ -610,9 +610,11 @@ command_process_netinfo_cell(cell_t *cell, or_connection_t *conn) conn->_base.address, (int)conn->_base.port, apparent_skew>0 ? "ahead" : "behind", dbuf, apparent_skew>0 ? "behind" : "ahead"); - control_event_general_status(LOG_WARN, - "CLOCK_SKEW SKEW=%ld SOURCE=OR:%s:%d", - apparent_skew, conn->_base.address, conn->_base.port); + if (severity == LOG_WARN) /* only tell the controller if an authority */ + control_event_general_status(LOG_WARN, + "CLOCK_SKEW SKEW=%ld SOURCE=OR:%s:%d", + apparent_skew, + conn->_base.address, conn->_base.port); } /* XXX maybe act on my_apparent_addr, if the source is sufficiently -- 2.11.4.GIT