Fix NPE while decoding authority section of a DNS response

Motivation:

NullPointerException is raised when a DNS response conrains a resource
record whose NAME is empty, which is the case for the authority section.

Modification:

Allow an empty name for DnsEntry. Only disallow an empty name for
DnsQuestion.

Result:

Fixes #2686
This commit is contained in:
Trustin Lee 2014-07-21 16:37:49 -07:00
parent a8e03106eb
commit 0983166699
4 changed files with 41 additions and 17 deletions

View File

@ -317,9 +317,6 @@ public class DnsEntry {
if (name == null) {
throw new NullPointerException("name");
}
if (name.isEmpty()) {
throw new IllegalArgumentException("name must not be left blank.");
}
if ((type & 0xffff) != type) {
throw new IllegalArgumentException("type must be an unsigned short.");
}

View File

@ -49,6 +49,10 @@ public final class DnsQuestion extends DnsEntry {
*/
public DnsQuestion(String name, int type, int qClass) {
super(name, type, qClass);
if (name.isEmpty()) {
throw new IllegalArgumentException("name must not be left blank.");
}
}
@Override

View File

@ -110,8 +110,9 @@ public class DnsResponseDecoder extends MessageToMessageDecoder<DatagramPacket>
buf.readerIndex(position);
}
if (name.length() == 0) {
return null;
return "";
}
return name.substring(0, name.length() - 1);
}

View File

@ -31,20 +31,42 @@ import java.net.InetSocketAddress;
public class DnsResponseTest {
private static final byte[][] packets = {
{ 0, 1, -127, -128, 0, 1, 0, 1, 0, 0, 0, 0, 3, 119, 119, 119, 7, 101, 120, 97, 109, 112, 108, 101, 3, 99,
111, 109, 0, 0, 1, 0, 1, -64, 12, 0, 1, 0, 1, 0, 0, 16, -113, 0, 4, -64, 0, 43, 10 },
{ 0, 1, -127, -128, 0, 1, 0, 1, 0, 0, 0, 0, 3, 119, 119, 119, 7, 101, 120, 97, 109, 112, 108, 101, 3, 99,
111, 109, 0, 0, 28, 0, 1, -64, 12, 0, 28, 0, 1, 0, 0, 69, -8, 0, 16, 32, 1, 5, 0, 0, -120, 2, 0, 0,
0, 0, 0, 0, 0, 0, 16 },
{ 0, 2, -127, -128, 0, 1, 0, 0, 0, 1, 0, 0, 3, 119, 119, 119, 7, 101, 120, 97, 109, 112, 108, 101, 3, 99,
111, 109, 0, 0, 15, 0, 1, -64, 16, 0, 6, 0, 1, 0, 0, 3, -43, 0, 45, 3, 115, 110, 115, 3, 100, 110,
115, 5, 105, 99, 97, 110, 110, 3, 111, 114, 103, 0, 3, 110, 111, 99, -64, 49, 119, -4, 39, 112, 0,
0, 28, 32, 0, 0, 14, 16, 0, 18, 117, 0, 0, 0, 14, 16 },
{ 0, 3, -127, -128, 0, 1, 0, 1, 0, 0, 0, 0, 3, 119, 119, 119, 7, 101, 120, 97, 109, 112, 108, 101, 3, 99,
111, 109, 0, 0, 16, 0, 1, -64, 12, 0, 16, 0, 1, 0, 0, 84, 75, 0, 12, 11, 118, 61, 115, 112, 102,
49, 32, 45, 97, 108, 108 } };
{
0, 1, -127, -128, 0, 1, 0, 1, 0, 0, 0, 0, 3, 119, 119, 119, 7, 101, 120, 97, 109, 112, 108, 101, 3,
99, 111, 109, 0, 0, 1, 0, 1, -64, 12, 0, 1, 0, 1, 0, 0, 16, -113, 0, 4, -64, 0, 43, 10
},
{
0, 1, -127, -128, 0, 1, 0, 1, 0, 0, 0, 0, 3, 119, 119, 119, 7, 101, 120, 97, 109, 112, 108, 101, 3,
99, 111, 109, 0, 0, 28, 0, 1, -64, 12, 0, 28, 0, 1, 0, 0, 69, -8, 0, 16, 32, 1, 5, 0, 0, -120, 2,
0, 0, 0, 0, 0, 0, 0, 0, 16
},
{
0, 2, -127, -128, 0, 1, 0, 0, 0, 1, 0, 0, 3, 119, 119, 119, 7, 101, 120, 97, 109, 112, 108, 101, 3,
99, 111, 109, 0, 0, 15, 0, 1, -64, 16, 0, 6, 0, 1, 0, 0, 3, -43, 0, 45, 3, 115, 110, 115, 3, 100,
110, 115, 5, 105, 99, 97, 110, 110, 3, 111, 114, 103, 0, 3, 110, 111, 99, -64, 49, 119, -4, 39,
112, 0, 0, 28, 32, 0, 0, 14, 16, 0, 18, 117, 0, 0, 0, 14, 16
},
{
0, 3, -127, -128, 0, 1, 0, 1, 0, 0, 0, 0, 3, 119, 119, 119, 7, 101, 120, 97, 109, 112, 108, 101, 3,
99, 111, 109, 0, 0, 16, 0, 1, -64, 12, 0, 16, 0, 1, 0, 0, 84, 75, 0, 12, 11, 118, 61, 115, 112,
102, 49, 32, 45, 97, 108, 108
},
{
-105, 19, -127, 0, 0, 1, 0, 0, 0, 13, 0, 0, 2, 104, 112, 11, 116, 105, 109, 98, 111, 117, 100, 114,
101, 97, 117, 3, 111, 114, 103, 0, 0, 1, 0, 1, 0, 0, 2, 0, 1, 0, 7, -23, 0, 0, 20, 1, 68, 12, 82,
79, 79, 84, 45, 83, 69, 82, 86, 69, 82, 83, 3, 78, 69, 84, 0, 0, 0, 2, 0, 1, 0, 7, -23, 0, 0, 4, 1,
70, -64, 49, 0, 0, 2, 0, 1, 0, 7, -23, 0, 0, 4, 1, 69, -64, 49, 0, 0, 2, 0, 1, 0, 7, -23, 0, 0, 4,
1, 75, -64, 49, 0, 0, 2, 0, 1, 0, 7, -23, 0, 0, 4, 1, 67, -64, 49, 0, 0, 2, 0, 1, 0, 7, -23, 0, 0,
4, 1, 76, -64, 49, 0, 0, 2, 0, 1, 0, 7, -23, 0, 0, 4, 1, 71, -64, 49, 0, 0, 2, 0, 1, 0, 7, -23, 0,
0, 4, 1, 73, -64, 49, 0, 0, 2, 0, 1, 0, 7, -23, 0, 0, 4, 1, 66, -64, 49, 0, 0, 2, 0, 1, 0, 7, -23,
0, 0, 4, 1, 77, -64, 49, 0, 0, 2, 0, 1, 0, 7, -23, 0, 0, 4, 1, 65, -64, 49, 0, 0, 2, 0, 1, 0, 7,
-23, 0, 0, 4, 1, 72, -64, 49, 0, 0, 2, 0, 1, 0, 7, -23, 0, 0, 4, 1, 74, -64, 49
}
};
private static final byte[] malformedLoopPacket = { 0, 4, -127, -128, 0, 1, 0, 0, 0, 0, 0, 0, -64, 12, 0, 1, 0, 1 };
private static final byte[] malformedLoopPacket = {
0, 4, -127, -128, 0, 1, 0, 0, 0, 0, 0, 0, -64, 12, 0, 1, 0, 1
};
@Test
public void readResponseTest() throws Exception {