From 273902f6164dae02bbd2e89ce47d65b2dca7338e Mon Sep 17 00:00:00 2001
From: zzz <zzz@mail.i2p>
Date: Wed, 2 Sep 2020 13:26:10 +0000
Subject: [PATCH] SSU: Randomize intro key
---
router/java/src/net/i2p/router/Router.java | 1 +
.../router/transport/udp/UDPTransport.java | 27 +++++++++++++++++--
2 files changed, 26 insertions(+), 2 deletions(-)
diff --git a/router/java/src/net/i2p/router/Router.java b/router/java/src/net/i2p/router/Router.java
index e1984d8172..62ac1ec85b 100644
--- a/router/java/src/net/i2p/router/Router.java
+++ b/router/java/src/net/i2p/router/Router.java
@@ -1267,6 +1267,7 @@ public class Router implements RouterClock.ClockShiftListener {
synchronized(_configFileLock) {
removeConfigSetting(UDPTransport.PROP_INTERNAL_PORT);
removeConfigSetting(UDPTransport.PROP_EXTERNAL_PORT);
+ removeConfigSetting(UDPTransport.PROP_INTRO_KEY);
removeConfigSetting(NTCPTransport.PROP_I2NP_NTCP_PORT);
removeConfigSetting(NTCPTransport.PROP_NTCP2_SP);
removeConfigSetting(NTCPTransport.PROP_NTCP2_IV);
diff --git a/router/java/src/net/i2p/router/transport/udp/UDPTransport.java b/router/java/src/net/i2p/router/transport/udp/UDPTransport.java
index abc40021bf..37617a8761 100644
--- a/router/java/src/net/i2p/router/transport/udp/UDPTransport.java
+++ b/router/java/src/net/i2p/router/transport/udp/UDPTransport.java
@@ -20,8 +20,10 @@ import java.util.concurrent.atomic.AtomicLong;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CopyOnWriteArrayList;
+import net.i2p.CoreVersion;
import net.i2p.crypto.HMACGenerator;
import net.i2p.crypto.SigType;
+import net.i2p.data.Base64;
import net.i2p.data.DatabaseEntry;
import net.i2p.data.DataHelper;
import net.i2p.data.Hash;
@@ -180,6 +182,8 @@ public class UDPTransport extends TransportImpl implements TimedWeightedPriority
/** override the "large" (max) MTU, default is PeerState.LARGE_MTU */
private static final String PROP_DEFAULT_MTU = "i2np.udp.mtu";
private static final String PROP_ADVANCED = "routerconsole.advanced";
+ /** @since 0.9.48 */
+ public static final String PROP_INTRO_KEY = "i2np.udp.introKey";
private static final String CAP_TESTING = Character.toString(UDPAddress.CAPACITY_TESTING);
private static final String CAP_TESTING_INTRO = CAP_TESTING + UDPAddress.CAPACITY_INTRODUCER;
@@ -207,6 +211,7 @@ public class UDPTransport extends TransportImpl implements TimedWeightedPriority
/** minimum peers volunteering to be introducers if we need that */
private static final int MIN_INTRODUCER_POOL = 5;
static final long INTRODUCER_EXPIRATION_MARGIN = 20*60*1000L;
+ private static final long MIN_DOWNTIME_TO_REKEY = 30*24*60*60*1000L;
private static final int[] BID_VALUES = { 15, 20, 50, 65, 80, 95, 100, 115, TransportBid.TRANSIENT_FAIL };
private static final int FAST_PREFERRED_BID = 0;
@@ -382,8 +387,26 @@ public class UDPTransport extends TransportImpl implements TimedWeightedPriority
UDPPacket.clearCache();
if (_log.shouldLog(Log.WARN)) _log.warn("Starting SSU transport listening");
- _introKey = new SessionKey(new byte[SessionKey.KEYSIZE_BYTES]);
- System.arraycopy(_context.routerHash().getData(), 0, _introKey.getData(), 0, SessionKey.KEYSIZE_BYTES);
+ byte[] ikey = new byte[SessionKey.KEYSIZE_BYTES];
+ _introKey = new SessionKey(ikey);
+ if (VersionComparator.comp(CoreVersion.VERSION, "0.9.48") >= 0) {
+ String sikey = _context.getProperty(PROP_INTRO_KEY);
+ if (sikey != null &&
+ _context.getEstimatedDowntime() < MIN_DOWNTIME_TO_REKEY) {
+ byte[] saved = Base64.decode(sikey);
+ if (saved != null && saved.length == SessionKey.KEYSIZE_BYTES) {
+ System.arraycopy(saved, 0, ikey, 0, SessionKey.KEYSIZE_BYTES);
+ } else {
+ _context.random().nextBytes(ikey);
+ _context.router().saveConfig(PROP_INTRO_KEY, Base64.encode(ikey));
+ }
+ } else {
+ _context.random().nextBytes(ikey);
+ _context.router().saveConfig(PROP_INTRO_KEY, Base64.encode(ikey));
+ }
+ } else {
+ System.arraycopy(_context.routerHash().getData(), 0, ikey, 0, SessionKey.KEYSIZE_BYTES);
+ }
// bind host
// This is not exposed in the UI and in practice is always null.
--
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