Fix restoring active position on byte buffers

Wrong restored position lead to incomplete EDNS0 options parsing.
dnsjava · Apr 5, 2021 · a787f12 · a787f12
1 parent 505b4ce
commit a787f12
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Showing 3 changed files with 195 additions and 1 deletion.
diff --git a/src/main/java/org/xbill/DNS/DNSInput.java b/src/main/java/org/xbill/DNS/DNSInput.java
@@ -92,7 +92,7 @@ public void restoreActive(int pos) {
     if (pos > byteBuffer.capacity()) {
       throw new IllegalArgumentException("cannot set active region past end of input");
     }
-    byteBuffer.limit(byteBuffer.position());
+    byteBuffer.limit(pos);
   }
 
   /**

diff --git a/src/test/java/org/xbill/DNS/DNSInputTest.java b/src/test/java/org/xbill/DNS/DNSInputTest.java
@@ -137,6 +137,23 @@ void save_restore() {
     assertEquals(6, m_di.remaining());
   }
 
+  @Test
+  void save_set_restore() {
+    m_di.jump(4);
+    assertEquals(4, m_di.current());
+    assertEquals(6, m_di.remaining());
+
+    int save = m_di.saveActive();
+    assertEquals(10, save);
+    assertEquals(6, m_di.remaining());
+
+    m_di.setActive(4);
+    assertEquals(4, m_di.remaining());
+
+    m_di.restoreActive(save);
+    assertEquals(6, m_di.remaining());
+  }
+
   @Test
   void readU8_basic() throws WireParseException {
     int v1 = m_di.readU8();

diff --git a/src/test/java/org/xbill/DNS/EDNS0Messages.java b/src/test/java/org/xbill/DNS/EDNS0Messages.java
@@ -0,0 +1,177 @@
+package org.xbill.DNS;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import java.io.IOException;
+import org.junit.jupiter.api.Test;
+
+public class EDNS0Messages {
+
+  /* dig +nocookie foo.dns.addere.ch */
+  private static final byte[] EDNS0_EMPTY = {
+    0x7d, 0x59, 0x01, 0x20, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x03, 0x66, 0x6f, 0x6f,
+    0x03, 0x64, 0x6e, 0x73, 0x06, 0x61, 0x64, 0x64, 0x65, 0x72, 0x65, 0x02, 0x63, 0x68, 0x00, 0x00,
+    0x01, 0x00, 0x01, 0x00, 0x00, 0x29, 0x10, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
+  };
+
+  /* dig foo.dns.addere.ch */
+  private static final byte[] EDNS0_COOKIE = {
+    (byte) 0x95,
+    (byte) 0xa6,
+    0x01,
+    0x20,
+    0x00,
+    0x01,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x01,
+    0x03,
+    0x66,
+    0x6f,
+    0x6f,
+    0x03,
+    0x64,
+    0x6e,
+    0x73,
+    0x06,
+    0x61,
+    0x64,
+    0x64,
+    0x65,
+    0x72,
+    0x65,
+    0x02,
+    0x63,
+    0x68,
+    0x00,
+    0x00,
+    0x01,
+    0x00,
+    0x01,
+    0x00,
+    0x00,
+    0x29,
+    0x10,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x0c,
+    0x00,
+    0x0a,
+    0x00,
+    0x08,
+    0x28,
+    0x75,
+    (byte) 0x83,
+    0x7f,
+    0x00,
+    0x32,
+    (byte) 0xe5,
+    0x6f
+  };
+
+  /* dig +keepalive foo.dns.addere.ch */
+  private static final byte[] EDNS0_COOKIE_KEEPALIVE = {
+    (byte) 0x8e,
+    (byte) 0xdd,
+    0x01,
+    0x20,
+    0x00,
+    0x01,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x01,
+    0x03,
+    0x66,
+    0x6f,
+    0x6f,
+    0x03,
+    0x64,
+    0x6e,
+    0x73,
+    0x06,
+    0x61,
+    0x64,
+    0x64,
+    0x65,
+    0x72,
+    0x65,
+    0x02,
+    0x63,
+    0x68,
+    0x00,
+    0x00,
+    0x01,
+    0x00,
+    0x01,
+    0x00,
+    0x00,
+    0x29,
+    0x10,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x10,
+    0x00,
+    0x0a,
+    0x00,
+    0x08,
+    (byte) 0xeb,
+    (byte) 0xed,
+    (byte) 0xfc,
+    0x4c,
+    0x1c,
+    0x45,
+    0x20,
+    0x01,
+    0x00,
+    0x0b,
+    0x00,
+    0x00
+  };
+
+  /* dig +keepalive +subnet=1.2.3.4 foo.dns.addere.ch */
+  private static final byte[] EDNS0_SUBNET_COOKIE_KEEPALIVE = {
+    0x42, 0x3a, 0x01, 0x20, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x03, 0x66, 0x6f, 0x6f,
+    0x03, 0x64, 0x6e, 0x73, 0x06, 0x61, 0x64, 0x64, 0x65, 0x72, 0x65, 0x02, 0x63, 0x68, 0x00, 0x00,
+    0x01, 0x00, 0x01, 0x00, 0x00, 0x29, 0x10, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x1c, 0x00, 0x08,
+    0x00, 0x08, 0x00, 0x01, 0x20, 0x00, 0x01, 0x02, 0x03, 0x04, 0x00, 0x0a, 0x00, 0x08, 0x7c, 0x2e,
+    0x0d, 0x0e, (byte) 0x95, (byte) 0xf3, 0x4d, (byte) 0xff, 0x00, 0x0b, 0x00, 0x00
+  };
+
+  @Test
+  void testParseEdns0Empty() throws IOException {
+    Message msg = new Message(EDNS0_EMPTY);
+    assertArrayEquals(EDNS0_EMPTY, msg.toWire());
+  }
+
+  @Test
+  void testParseEdns0Cookie() throws IOException {
+    Message msg = new Message(EDNS0_COOKIE);
+    assertArrayEquals(EDNS0_COOKIE, msg.toWire());
+  }
+
+  @Test
+  void testParseEdns0CookieKeepalive() throws IOException {
+    Message msg = new Message(EDNS0_COOKIE_KEEPALIVE);
+    assertArrayEquals(EDNS0_COOKIE_KEEPALIVE, msg.toWire());
+  }
+
+  @Test
+  void testParseEdns0SubnetCookieKeepalive() throws IOException {
+    Message msg = new Message(EDNS0_SUBNET_COOKIE_KEEPALIVE);
+    assertArrayEquals(EDNS0_SUBNET_COOKIE_KEEPALIVE, msg.toWire());
+  }
+}