From 7610b3842f2ff85baf8f0b1f3cdec634d062eea7 Mon Sep 17 00:00:00 2001
From: zzz <zzz@i2pmail.org>
Date: Thu, 16 Jun 2022 08:22:55 -0400
Subject: [PATCH] SSU2: Hole punch processing
Validate and process hole punch payload
Send session request immediately after receiving hole punch
Remove some unused code
Log tweaks
---
.../transport/udp/EstablishmentManager.java | 241 +++++++++++++++---
.../udp/OutboundEstablishState2.java | 21 +-
2 files changed, 219 insertions(+), 43 deletions(-)
diff --git a/router/java/src/net/i2p/router/transport/udp/EstablishmentManager.java b/router/java/src/net/i2p/router/transport/udp/EstablishmentManager.java
index 05df8548ff..a51a49c239 100644
--- a/router/java/src/net/i2p/router/transport/udp/EstablishmentManager.java
+++ b/router/java/src/net/i2p/router/transport/udp/EstablishmentManager.java
@@ -160,6 +160,7 @@ class EstablishmentManager {
// SSU 2
private static final int MAX_TOKENS = 512;
public static final long IB_TOKEN_EXPIRATION = 60*60*1000L;
+ private static final long MAX_SKEW = 2*60*1000;
public EstablishmentManager(RouterContext ctx, UDPTransport transport) {
@@ -1617,7 +1618,7 @@ class EstablishmentManager {
token = 0;
}
Hash bobHash = bob.getRemotePeer();
- Hash charlieHash = charlie.getRemoteHostId().getPeerHash();
+ Hash charlieHash = charlie.getRemoteIdentity().getHash();
RouterInfo bobRI = _context.netDb().lookupRouterInfoLocally(bobHash);
RouterInfo charlieRI = _context.netDb().lookupRouterInfoLocally(charlieHash);
Hash signer;
@@ -1636,16 +1637,19 @@ class EstablishmentManager {
if (signerRI != null) {
// validate signed data
SigningPublicKey spk = signerRI.getIdentity().getSigningPublicKey();
- if (SSU2Util.validateSig(_context, SSU2Util.RELAY_RESPONSE_PROLOGUE,
+ if (!SSU2Util.validateSig(_context, SSU2Util.RELAY_RESPONSE_PROLOGUE,
bobHash, null, data, spk)) {
- } else {
if (_log.shouldWarn())
_log.warn("Signature failed relay response " + code + " as alice from:\n" + signerRI);
istate = INTRO_STATE_FAILED;
+ charlie2.setIntroState(bobHash, istate);
+ charlie.fail();
+ return;
}
} else {
if (_log.shouldWarn())
_log.warn("Signer RI not found " + signer);
+ return;
}
if (code == 0) {
int iplen = data[9] & 0xff;
@@ -1657,7 +1661,6 @@ class EstablishmentManager {
charlie.fail();
return;
}
- boolean isIPv6 = iplen == 18;
int port = (int) DataHelper.fromLong(data, 10, 2);
byte[] ip = new byte[iplen - 2];
System.arraycopy(data, 12, ip, 0, iplen - 2);
@@ -1674,15 +1677,6 @@ class EstablishmentManager {
charlie.fail();
return;
}
- InetAddress charlieIP;
- try {
- charlieIP = InetAddress.getByAddress(ip);
- } catch (UnknownHostException uhe) {
- istate = INTRO_STATE_FAILED;
- charlie2.setIntroState(bobHash, istate);
- charlie.fail();
- return;
- }
if (_log.shouldDebug())
_log.debug("Received RelayResponse from " + charlie + " - they are on " +
Addresses.toString(ip, port));
@@ -1695,24 +1689,29 @@ class EstablishmentManager {
}
synchronized (charlie) {
RemoteHostId oldId = charlie.getRemoteHostId();
- ((OutboundEstablishState2) charlie).introduced(ip, port, token);
- RemoteHostId newId = charlie.getRemoteHostId();
- addOutboundToken(newId, token, _context.clock().now() + 10*1000);
- // Swap out the RemoteHostId the state is indexed under.
- // It was a Hash, change it to a IP/port.
- // Remove the entry in the byClaimedAddress map as it's now in main map.
- // Add an entry in the byHash map so additional OB pkts can find it.
- _outboundByHash.put(charlieHash, charlie);
- RemoteHostId claimed = charlie.getClaimedAddress();
- if (!oldId.equals(newId)) {
- _outboundStates.remove(oldId);
- _outboundStates.put(newId, charlie);
- if (_log.shouldLog(Log.INFO))
- _log.info("RR replaced " + oldId + " with " + newId + ", claimed address was " + claimed);
+ if (oldId.getIP() == null) {
+ // relay response before hole punch
+ ((OutboundEstablishState2) charlie).introduced(ip, port, token);
+ RemoteHostId newId = charlie.getRemoteHostId();
+ addOutboundToken(newId, token, _context.clock().now() + 10*1000);
+ // Swap out the RemoteHostId the state is indexed under.
+ // It was a Hash, change it to a IP/port.
+ // Remove the entry in the byClaimedAddress map as it's now in main map.
+ // Add an entry in the byHash map so additional OB pkts can find it.
+ _outboundByHash.put(charlieHash, charlie);
+ RemoteHostId claimed = charlie.getClaimedAddress();
+ if (!oldId.equals(newId)) {
+ _outboundStates.remove(oldId);
+ _outboundStates.put(newId, charlie);
+ if (_log.shouldLog(Log.INFO))
+ _log.info("RR replaced " + oldId + " with " + newId + ", claimed address was " + claimed);
+ }
+ //
+ if (claimed != null)
+ _outboundByClaimedAddress.remove(oldId, charlie); // only if == state
+ } else {
+ // TODO validate same IP/port as in hole punch?
}
- //
- if (claimed != null)
- _outboundByClaimedAddress.remove(oldId, charlie); // only if == state
}
charlie2.setIntroState(bobHash, istate);
notifyActivity();
@@ -1745,6 +1744,8 @@ class EstablishmentManager {
RemoteHostId id = new RemoteHostId(from.getAddress(), fromPort);
OutboundEstablishState state = _outboundStates.get(id);
if (state != null) {
+ // this is the usual case, we already received the RelayResponse (1 RTT)
+ // before the HolePunch (1 1/2 RTT)
boolean sendNow = state.receiveHolePunch();
if (sendNow) {
if (_log.shouldDebug())
@@ -1786,14 +1787,47 @@ class EstablishmentManager {
chacha.initializeKey(introKey, 0);
long n = DataHelper.fromLong(data, off + PKT_NUM_OFFSET, 4);
chacha.setNonce(n);
+ HPCallback cb = new HPCallback(id);
+ long now = _context.clock().now();
+ long nonce;
try {
// decrypt in-place
chacha.decryptWithAd(data, off, LONG_HEADER_SIZE,
data, off + LONG_HEADER_SIZE, data, off + LONG_HEADER_SIZE, len - LONG_HEADER_SIZE);
int payloadLen = len - (LONG_HEADER_SIZE + MAC_LEN);
- SSU2Payload.PayloadCallback cb = new HPCallback(id);
SSU2Payload.processPayload(_context, cb, data, off + LONG_HEADER_SIZE, payloadLen, false);
- // TODO process cb fields
+ if (cb._respCode != 0) {
+ if (_log.shouldWarn())
+ _log.warn("Bad HolePunch response: " + cb._respCode);
+ return;
+ }
+ long skew = cb._timeReceived - now;
+ if (skew > MAX_SKEW || skew < 0 - MAX_SKEW) {
+ if (_log.shouldWarn())
+ _log.warn("Too skewed in hole punch from " + id);
+ return;
+ }
+ nonce = DataHelper.fromLong(cb._respData, 0, 4);
+ if (nonce != (rcvConnID & 0xFFFFFFFFL) ||
+ nonce != ((rcvConnID >> 32) & 0xFFFFFFFFL)) {
+ if (_log.shouldWarn())
+ _log.warn("Bad nonce in hole punch from " + id);
+ return;
+ }
+ long time = DataHelper.fromLong(cb._respData, 4, 4) * 1000;
+ skew = time - now;
+ if (skew > MAX_SKEW || skew < 0 - MAX_SKEW) {
+ if (_log.shouldWarn())
+ _log.warn("Too skewed in hole punch from " + id);
+ return;
+ }
+ int ver = cb._respData[8] & 0xff;
+ if (ver != 2) {
+ if (_log.shouldWarn())
+ _log.warn("Bad hole punch version " + ver + " from " + id);
+ return;
+ }
+ // check signature below
} catch (Exception e) {
if (_log.shouldWarn())
_log.warn("Bad HolePunch packet:\n" + HexDump.dump(data, off, len), e);
@@ -1805,19 +1839,141 @@ class EstablishmentManager {
// TODO now we can look up by nonce instead if we want
OutboundEstablishState state = _outboundStates.get(id);
if (state != null) {
+ if (_log.shouldInfo())
+ _log.info("Hole punch after RelayResponse from " + state);
+ } else {
+ // This is the usual case, we received the HolePunch (1 1/2 RTT)
+ // before the RelayResponse (2 RTT), lookup by nonce.
+ state = _liveIntroductions.remove(Long.valueOf(nonce));
+ if (state != null) {
+ if (_log.shouldInfo())
+ _log.info("Hole punch before RelayResponse from " + state);
+ } else {
+ if (_log.shouldLog(Log.INFO))
+ _log.info("No state found for SSU2 hole punch from " + id);
+ return;
+ }
+ }
+ if (state.getVersion() != 2)
+ return;
+ OutboundEstablishState2 state2 = (OutboundEstablishState2) state;
+ Hash charlieHash = state.getRemoteIdentity().getHash();
+ RouterInfo charlieRI = _context.netDb().lookupRouterInfoLocally(charlieHash);
+ if (charlieRI != null) {
+ // validate signed data, but we don't necessarily know which Bob
+ SigningPublicKey spk = charlieRI.getIdentity().getSigningPublicKey();
+ UDPAddress addr = state.getRemoteAddress();
+ int count = addr.getIntroducerCount();
+ data = Arrays.copyOfRange(cb._respData, 0, cb._respData.length - 8);
+ boolean ok = false;
+ loop:
+ for (int i = 0; i < count; i++) {
+ Hash h = addr.getIntroducerHash(i);
+ if (h != null) {
+ OutboundEstablishState2.IntroState istate = state2.getIntroState(h);
+ switch (istate) {
+ // probably not signed by this introducer
+ case INTRO_STATE_INIT:
+ case INTRO_STATE_EXPIRED:
+ case INTRO_STATE_REJECTED:
+ case INTRO_STATE_CONNECT_FAILED:
+ case INTRO_STATE_BOB_REJECT:
+ case INTRO_STATE_CHARLIE_REJECT:
+ case INTRO_STATE_FAILED:
+ case INTRO_STATE_INVALID:
+ case INTRO_STATE_DISCONNECTED:
+ continue;
+
+ // maybe or definitely signed by this introducer
+ case INTRO_STATE_LOOKUP_SENT:
+ case INTRO_STATE_HAS_RI:
+ case INTRO_STATE_CONNECTING:
+ case INTRO_STATE_CONNECTED:
+ case INTRO_STATE_RELAY_REQUEST_SENT:
+ case INTRO_STATE_RELAY_CHARLIE_ACCEPTED:
+ case INTRO_STATE_LOOKUP_FAILED:
+ case INTRO_STATE_RELAY_RESPONSE_TIMEOUT:
+ case INTRO_STATE_SUCCESS:
+ default:
+ if (SSU2Util.validateSig(_context, SSU2Util.RELAY_RESPONSE_PROLOGUE,
+ h, null, data, spk)) {
+ if (_log.shouldInfo())
+ _log.info("Good sig hole punch, credit " + h.toBase64() + " on " + state);
+ state2.setIntroState(h, INTRO_STATE_SUCCESS);
+ ok = true;
+ break loop;
+ }
+ break;
+ }
+ }
+ }
+ if (!ok) {
+ if (_log.shouldWarn())
+ _log.warn("Signature failed hole punch on " + state);
+ return;
+ }
+
+ int iplen = data[9] & 0xff;
+ if (iplen != 6 && iplen != 18) {
+ if (_log.shouldWarn())
+ _log.warn("Bad IP length " + iplen + " from " + state);
+ state.fail();
+ return;
+ }
+ int port = (int) DataHelper.fromLong(data, 10, 2);
+ byte[] ip = new byte[iplen - 2];
+ System.arraycopy(data, 12, ip, 0, iplen - 2);
+ // validate
+ if (!TransportUtil.isValidPort(port) ||
+ !_transport.isValid(ip) ||
+ _transport.isTooClose(ip) ||
+ _context.blocklist().isBlocklisted(ip)) {
+ if (_log.shouldLog(Log.WARN))
+ _log.warn("Bad hole punch from " + state + " for " + Addresses.toString(ip, port));
+ _context.statManager().addRateData("udp.relayBadIP", 1);
+ state.fail();
+ return;
+ }
+ if (_log.shouldDebug())
+ _log.debug("Received hole punch from " + state + " - they are on " +
+ Addresses.toString(ip, port));
+ synchronized (state) {
+ RemoteHostId oldId = state.getRemoteHostId();
+ if (oldId.getIP() == null) {
+ // hole punch before relay response
+ long token = DataHelper.fromLong8(cb._respData, cb._respData.length - 8);
+ state2.introduced(ip, port, token);
+ RemoteHostId newId = state.getRemoteHostId();
+ addOutboundToken(newId, token, now + 10*1000);
+ // Swap out the RemoteHostId the state is indexed under.
+ // It was a Hash, change it to a IP/port.
+ // Remove the entry in the byClaimedAddress map as it's now in main map.
+ // Add an entry in the byHash map so additional OB pkts can find it.
+ _outboundByHash.put(charlieHash, state);
+ RemoteHostId claimed = state.getClaimedAddress();
+ if (!oldId.equals(newId)) {
+ _outboundStates.remove(oldId);
+ _outboundStates.put(newId, state);
+ if (_log.shouldLog(Log.INFO))
+ _log.info("HP replaced " + oldId + " with " + newId + ", claimed address was " + claimed);
+ }
+ //
+ if (claimed != null)
+ _outboundByClaimedAddress.remove(oldId, state); // only if == state
+ } else {
+ // TODO validate same IP/port as in response?
+ }
+ }
boolean sendNow = state.receiveHolePunch();
if (sendNow) {
- if (_log.shouldDebug())
- _log.debug("Hole punch from " + state + ", sending SessionRequest now");
+ if (_log.shouldInfo())
+ _log.info("Send SessionRequest after HolePunch from " + state);
notifyActivity();
- } else {
- if (_log.shouldLog(Log.INFO))
- _log.info("Hole punch from " + state + ", already sent SessionRequest");
}
} else {
- // HolePunch received before RelayResponse, and we didn't know the IP/port, or it changed
- if (_log.shouldLog(Log.INFO))
- _log.info("No state found for SSU2 hole punch from " + id);
+ if (_log.shouldWarn())
+ _log.warn("Charlie RI not found " + state);
+ return;
}
}
@@ -2358,6 +2514,7 @@ class EstablishmentManager {
do {
token = _context.random().nextLong();
} while (token == 0);
+ // TODO shorten expiration based on _inboundTokens size
long expires = _context.clock().now() + IB_TOKEN_EXPIRATION;
Token tok = new Token(token, expires);
synchronized(_inboundTokens) {
@@ -2399,12 +2556,12 @@ class EstablishmentManager {
*
* @since 0.9.55
*/
- private class HPCallback implements SSU2Payload.PayloadCallback {
+ private static class HPCallback implements SSU2Payload.PayloadCallback {
private final RemoteHostId _from;
public long _timeReceived;
public byte[] _aliceIP;
public int _alicePort;
- public int _respCode;
+ public int _respCode = 999;
public byte[] _respData;
public HPCallback(RemoteHostId from) {
diff --git a/router/java/src/net/i2p/router/transport/udp/OutboundEstablishState2.java b/router/java/src/net/i2p/router/transport/udp/OutboundEstablishState2.java
index da01ec7f4d..5c644cd683 100644
--- a/router/java/src/net/i2p/router/transport/udp/OutboundEstablishState2.java
+++ b/router/java/src/net/i2p/router/transport/udp/OutboundEstablishState2.java
@@ -358,6 +358,25 @@ class OutboundEstablishState2 extends OutboundEstablishState implements SSU2Payl
return rv;
}
+ /**
+ * Overridden because we don't have to wait for Relay Response first.
+ *
+ * @return true if we should send the SessionRequest now
+ * @since 0.9.55
+ */
+ @Override
+ synchronized boolean receiveHolePunch() {
+ if (_currentState == OutboundState.OB_STATE_PENDING_INTRO)
+ _currentState = OutboundState.OB_STATE_INTRODUCED;
+ else if (_currentState != OutboundState.OB_STATE_INTRODUCED)
+ return false;
+ if (_requestSentCount > 0)
+ return false;
+ long now = _context.clock().now();
+ _nextSend = now;
+ return true;
+ }
+
// SSU 2 things
@Override
@@ -666,7 +685,7 @@ class OutboundEstablishState2 extends OutboundEstablishState implements SSU2Payl
synchronized(_introducers) {
old = _introducers.put(h, state);
}
- if (_log.shouldDebug())
+ if (old != state && _log.shouldDebug())
_log.debug("Change state for introducer " + h.toBase64() + " from " + old + " to " + state + " on " + this);
}
--
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