From 6cef4ccbb195a116557fe21c122f78ee2a2d0958 Mon Sep 17 00:00:00 2001
From: zzz <zzz@i2pmail.org>
Date: Fri, 7 Feb 2025 12:18:52 -0500
Subject: [PATCH] Data: Check key order when parsing RI mappings and fail-fast
 if out-of-order

before the signature check
---
 core/java/src/net/i2p/data/DataHelper.java    | 28 ++++++++++++++++++-
 .../net/i2p/data/router/RouterAddress.java    |  4 ++-
 .../src/net/i2p/data/router/RouterInfo.java   |  4 ++-
 3 files changed, 33 insertions(+), 3 deletions(-)

diff --git a/core/java/src/net/i2p/data/DataHelper.java b/core/java/src/net/i2p/data/DataHelper.java
index 0177096f8..35eb51fde 100644
--- a/core/java/src/net/i2p/data/DataHelper.java
+++ b/core/java/src/net/i2p/data/DataHelper.java
@@ -134,7 +134,8 @@ public class DataHelper {
      * is repeated until there are no more bytes (not characters!) left as defined by the
      * first two byte integer.
      *
-     *  As of 0.9.18, throws DataFormatException on duplicate key
+     * As of 0.9.18, throws DataFormatException on duplicate key
+     * Does NOT enforce key ordering.
      *
      * @param rawStream stream to read the mapping from
      * @throws DataFormatException if the format is invalid
@@ -152,6 +153,7 @@ public class DataHelper {
      *  Ditto, load into an existing properties
      *
      *  As of 0.9.18, throws DataFormatException on duplicate key
+     *  Does NOT enforce key ordering.
      *
      *  @param props The Properties to load into.
      *               As of 0.9.38, if null, a new OrderedProperties will be created.
@@ -163,6 +165,26 @@ public class DataHelper {
      *  @since 0.8.13
      */
     public static Properties readProperties(InputStream rawStream, Properties props) 
+        throws DataFormatException, IOException {
+        return readProperties(rawStream, props, false);
+    }
+
+    /**
+     *  Ditto, load into an existing properties
+     *
+     *  As of 0.9.18, throws DataFormatException on duplicate key
+     *
+     *  @param props The Properties to load into.
+     *               As of 0.9.38, if null, a new OrderedProperties will be created.
+     *  @param rawStream stream to read the mapping from
+     *  @param enforceOrder if true, throw DataFormatException if keys are not ordered
+     *  @throws DataFormatException if the format is invalid
+     *  @throws IOException if there is a problem reading the data
+     *  @return the parameter props, or (as of 0.9.38) a new OrderedProperties if props is null,
+     *                               and an immutable EmptyProperties if empty.
+     *  @since 0.9.66
+     */
+    public static Properties readProperties(InputStream rawStream, Properties props, boolean enforceOrder) 
         throws DataFormatException, IOException {
         int size = (int) readLong(rawStream, 2);
         if (size == 0) {
@@ -174,11 +196,15 @@ public class DataHelper {
         // full read guaranteed
         read(rawStream, data);
         ByteArrayInputStream in = new ByteArrayInputStream(data);
+        String prev = "";
         while (in.available() > 0) {
             String key = readString(in);
             String cached = _propertiesKeyCache.get(key);
             if (cached != null)
                 key = cached;
+            if (enforceOrder && key.compareTo(prev) <= 0)
+                throw new DataFormatException("option " + key + " out of order");
+            prev = key;
             int b = in.read();
             if (b != '=')
                 throw new DataFormatException("Bad key");
diff --git a/router/java/src/net/i2p/data/router/RouterAddress.java b/router/java/src/net/i2p/data/router/RouterAddress.java
index 21ab3c9f3..02ac8278c 100644
--- a/router/java/src/net/i2p/data/router/RouterAddress.java
+++ b/router/java/src/net/i2p/data/router/RouterAddress.java
@@ -292,7 +292,9 @@ public class RouterAddress extends DataStructureImpl {
             _transportStyle = "NTCP";
         else if (_transportStyle.equals("SSU2"))
             _transportStyle = "SSU2";
-        DataHelper.readProperties(in, _options);
+        // enforce mapping order so bad ones will fail-fast
+        // before the signature check
+        DataHelper.readProperties(in, _options, true);
     }
     
     /**
diff --git a/router/java/src/net/i2p/data/router/RouterInfo.java b/router/java/src/net/i2p/data/router/RouterInfo.java
index d8dae8d64..49cebff4d 100644
--- a/router/java/src/net/i2p/data/router/RouterInfo.java
+++ b/router/java/src/net/i2p/data/router/RouterInfo.java
@@ -606,7 +606,9 @@ public class RouterInfo extends DatabaseEntry {
                 _peers.add(peerIdentityHash);
             }
         }
-        DataHelper.readProperties(din, _options);
+        // enforce mapping order so bad ones will fail-fast
+        // before the signature check
+        DataHelper.readProperties(din, _options, true);
         _signature = new Signature(type);
         _signature.readBytes(in);