aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorNick Mathewson <nickm@torproject.org>2013-10-31 16:44:14 -0400
committerNick Mathewson <nickm@torproject.org>2013-11-01 10:04:48 -0400
commit0de71bf8eb5031b1c6539ea48627a938e200b5da (patch)
treee0c690019892551b5671e2c32047645c253f5274
parent5cc155e02a995fda828ff33b105040b2bd96a650 (diff)
downloadtor-0de71bf8eb5031b1c6539ea48627a938e200b5da.tar
tor-0de71bf8eb5031b1c6539ea48627a938e200b5da.tar.gz
Implement proposal 221: Stop sending CREATE_FAST
This makes FastFirstHopPK an AUTOBOOL; makes the default "auto"; and makes the behavior of "auto" be "look at the consensus."
-rw-r--r--changes/prop2216
-rw-r--r--doc/tor.1.txt8
-rw-r--r--src/or/circuitbuild.c8
-rw-r--r--src/or/config.c2
4 files changed, 17 insertions, 7 deletions
diff --git a/changes/prop221 b/changes/prop221
new file mode 100644
index 000000000..b2bf44bc3
--- /dev/null
+++ b/changes/prop221
@@ -0,0 +1,6 @@
+ o Minor features:
+ - Stop sending the CREATE_FAST cells by default; instead, use a
+ parameter in the consensus to decide whether to use
+ CREATE_FAST. This can improve security on connections where
+ Tor's circuit handshake is stronger than the available TLS
+ connection security levels. Implements proposal 221.
diff --git a/doc/tor.1.txt b/doc/tor.1.txt
index b9ee29614..51d2aab2d 100644
--- a/doc/tor.1.txt
+++ b/doc/tor.1.txt
@@ -1115,15 +1115,17 @@ The following options are useful only for clients (that is, if
the node "foo". Disabled by default since attacking websites and exit
relays can use it to manipulate your path selection. (Default: 0)
-[[FastFirstHopPK]] **FastFirstHopPK** **0**|**1**::
+[[FastFirstHopPK]] **FastFirstHopPK** **0**|**1**|**auto**::
When this option is disabled, Tor uses the public key step for the first
hop of creating circuits. Skipping it is generally safe since we have
already used TLS to authenticate the relay and to establish forward-secure
- keys. Turning this option off makes circuit building slower. +
+ keys. Turning this option off makes circuit building a little
+ slower. Setting this option to "auto" takes advice from the authorities
+ in the latest consensus about whether to use this feature. +
+
Note that Tor will always use the public key step for the first hop if it's
operating as a relay, and it will never use the public key step if it
- doesn't yet know the onion key of the first hop. (Default: 1)
+ doesn't yet know the onion key of the first hop. (Default: auto)
[[TransPort]] **TransPort** \['address':]__port__|**auto** [_isolation flags_]::
Open this port to listen for transparent proxy connections. Set this to
diff --git a/src/or/circuitbuild.c b/src/or/circuitbuild.c
index 43d2ffe4d..26c1e8982 100644
--- a/src/or/circuitbuild.c
+++ b/src/or/circuitbuild.c
@@ -600,16 +600,18 @@ should_use_create_fast_for_circuit(origin_circuit_t *circ)
if (!circ->cpath->extend_info->onion_key)
return 1; /* our hand is forced: only a create_fast will work. */
- if (!options->FastFirstHopPK)
- return 0; /* we prefer to avoid create_fast */
if (public_server_mode(options)) {
/* We're a server, and we know an onion key. We can choose.
* Prefer to blend our circuit into the other circuits we are
* creating on behalf of others. */
return 0;
}
+ if (options->FastFirstHopPK == -1) {
+ /* option is "auto", so look at the consensus. */
+ return networkstatus_get_param(NULL, "usecreatefast", 1, 0, 1);
+ }
- return 1;
+ return options->FastFirstHopPK;
}
/** Return true if <b>circ</b> is the type of circuit we want to count
diff --git a/src/or/config.c b/src/or/config.c
index 18f1c2950..491b2cd87 100644
--- a/src/or/config.c
+++ b/src/or/config.c
@@ -236,7 +236,7 @@ static config_var_t option_vars_[] = {
OBSOLETE("FallbackNetworkstatusFile"),
V(FascistFirewall, BOOL, "0"),
V(FirewallPorts, CSV, ""),
- V(FastFirstHopPK, BOOL, "1"),
+ V(FastFirstHopPK, AUTOBOOL, "auto"),
V(FetchDirInfoEarly, BOOL, "0"),
V(FetchDirInfoExtraEarly, BOOL, "0"),
V(FetchServerDescriptors, BOOL, "1"),