Don't crash if we get a DHCP packet with the wrong port.
This should only happen if we get a packet in the small time
window between binding the packet socket and programming the
BPF filter on it.
Bug: 26696823
Change-Id: I481f1bc74bbaeb9646d96e1841d2a69acdb47d62
diff --git a/services/net/java/android/net/dhcp/DhcpPacket.java b/services/net/java/android/net/dhcp/DhcpPacket.java
index 8927bfa..84d99e4 100644
--- a/services/net/java/android/net/dhcp/DhcpPacket.java
+++ b/services/net/java/android/net/dhcp/DhcpPacket.java
@@ -804,7 +804,11 @@
// server-to-server packets, e.g. for relays.
if (!isPacketToOrFromClient(udpSrcPort, udpDstPort) &&
!isPacketServerToServer(udpSrcPort, udpDstPort)) {
- return null;
+ // This should almost never happen because we use SO_ATTACH_FILTER on the packet
+ // socket to drop packets that don't have the right source ports. However, it's
+ // possible that a packet arrives between when the socket is bound and when the
+ // filter is set. http://b/26696823 .
+ throw new ParseException("Unexpected UDP ports %d->%d", udpSrcPort, udpDstPort);
}
}
diff --git a/services/tests/servicestests/src/android/net/dhcp/DhcpPacketTest.java b/services/tests/servicestests/src/android/net/dhcp/DhcpPacketTest.java
index 7e60bf1..3d55c6e 100644
--- a/services/tests/servicestests/src/android/net/dhcp/DhcpPacketTest.java
+++ b/services/tests/servicestests/src/android/net/dhcp/DhcpPacketTest.java
@@ -552,6 +552,39 @@
}
@SmallTest
+ public void testUdpInvalidDstPort() throws Exception {
+ final ByteBuffer packet = ByteBuffer.wrap(HexEncoding.decode((
+ // Ethernet header.
+ "9cd917000000001c2e0000000800" +
+ // IP header.
+ "45a00148000040003d115087d18194fb0a0f7af2" +
+ // UDP header. TODO: fix invalid checksum (due to MAC address obfuscation).
+ // NOTE: The destination port is a non-DHCP port.
+ "0043aaaa01341268" +
+ // BOOTP header.
+ "02010600d628ba8200000000000000000a0f7af2000000000a0fc818" +
+ // MAC address.
+ "9cd91700000000000000000000000000" +
+ // Server name.
+ "0000000000000000000000000000000000000000000000000000000000000000" +
+ "0000000000000000000000000000000000000000000000000000000000000000" +
+ // File.
+ "0000000000000000000000000000000000000000000000000000000000000000" +
+ "0000000000000000000000000000000000000000000000000000000000000000" +
+ "0000000000000000000000000000000000000000000000000000000000000000" +
+ "0000000000000000000000000000000000000000000000000000000000000000" +
+ // Options.
+ "6382536335010236040a0169fc3304000151800104ffff000003040a0fc817060cd1818003d1819403" +
+ "d18180060f0777766d2e6564751c040a0fffffff000000"
+ ).toCharArray(), false));
+
+ try {
+ DhcpPacket.decodeFullPacket(packet, ENCAP_L2);
+ fail("Packet with invalid dst port did not throw ParseException");
+ } catch (ParseException expected) {}
+ }
+
+ @SmallTest
public void testMultipleRouters() throws Exception {
final ByteBuffer packet = ByteBuffer.wrap(HexEncoding.decode((
// Ethernet header.