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Merge "APF: filter unwanted ARP replies" into nyc-mr1-dev

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TreeHugger Robot
2016-07-15 03:59:48 +00:00
committed by Android (Google) Code Review
parent 4595bc7f12 38db976514
commit b91c1232ee
2 changed files with 111 additions and 43 deletions
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54
services/net/java/android/net/apf/ApfFilter.java
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@@ -180,6 +180,7 @@ public class ApfFilter {
private static final int IPV4_FRAGMENT_OFFSET_MASK = 0x1fff;
private static final int IPV4_PROTOCOL_OFFSET = ETH_HEADER_LEN + 9;
private static final int IPV4_DEST_ADDR_OFFSET = ETH_HEADER_LEN + 16;
private static final int IPV4_ANY_HOST_ADDRESS = 0;
private static final int IPV6_NEXT_HEADER_OFFSET = ETH_HEADER_LEN + 6;
private static final int IPV6_SRC_ADDR_OFFSET = ETH_HEADER_LEN + 8;
@@ -201,12 +202,14 @@ public class ApfFilter {
private static final int DHCP_CLIENT_MAC_OFFSET = ETH_HEADER_LEN + UDP_HEADER_LEN + 28;
private static final int ARP_HEADER_OFFSET = ETH_HEADER_LEN;
private static final byte[] ARP_IPV4_REQUEST_HEADER = new byte[]{
private static final int ARP_OPCODE_OFFSET = ARP_HEADER_OFFSET + 6;
private static final short ARP_OPCODE_REQUEST = 1;
private static final short ARP_OPCODE_REPLY = 2;
private static final byte[] ARP_IPV4_HEADER = new byte[]{
0, 1, // Hardware type: Ethernet (1)
8, 0, // Protocol type: IP (0x0800)
6, // Hardware size: 6
4, // Protocol size: 4
0, 1 // Opcode: request (1)
};
private static final int ARP_TARGET_IP_ADDRESS_OFFSET = ETH_HEADER_LEN + 24;
@@ -667,23 +670,48 @@ public class ApfFilter {
private void generateArpFilterLocked(ApfGenerator gen) throws IllegalInstructionException {
// Here's a basic summary of what the ARP filter program does:
//
// if interface has IPv4 address:
// if it's not an ARP IPv4 request:
// pass
// if it's not a request for our IPv4 address:
// drop
// if not ARP IPv4
// pass
// if not ARP IPv4 reply or request
// pass
// if unicast ARP reply
// pass
// if interface has no IPv4 address
// if target ip is 0.0.0.0
// drop
// else
// if target ip is not the interface ip
// drop
// pass
if (mIPv4Address != null) {
// if it's not an ARP IPv4 request, pass
gen.addLoadImmediate(Register.R0, ARP_HEADER_OFFSET);
gen.addJumpIfBytesNotEqual(Register.R0, ARP_IPV4_REQUEST_HEADER, gen.PASS_LABEL);
// if it's not a request for our IPv4 address, drop
final String checkTargetIPv4 = "checkTargetIPv4";
// Pass if not ARP IPv4.
gen.addLoadImmediate(Register.R0, ARP_HEADER_OFFSET);
gen.addJumpIfBytesNotEqual(Register.R0, ARP_IPV4_HEADER, gen.PASS_LABEL);
// Pass if unknown ARP opcode.
gen.addLoad16(Register.R0, ARP_OPCODE_OFFSET);
gen.addJumpIfR0Equals(ARP_OPCODE_REQUEST, checkTargetIPv4); // Skip to unicast check
gen.addJumpIfR0NotEquals(ARP_OPCODE_REPLY, gen.PASS_LABEL);
// Pass if unicast reply.
gen.addLoadImmediate(Register.R0, ETH_DEST_ADDR_OFFSET);
gen.addJumpIfBytesNotEqual(Register.R0, ETH_BROADCAST_MAC_ADDRESS, gen.PASS_LABEL);
// Either a unicast request, a unicast reply, or a broadcast reply.
gen.defineLabel(checkTargetIPv4);
if (mIPv4Address == null) {
// When there is no IPv4 address, drop GARP replies (b/29404209).
gen.addLoad32(Register.R0, ARP_TARGET_IP_ADDRESS_OFFSET);
gen.addJumpIfR0Equals(IPV4_ANY_HOST_ADDRESS, gen.DROP_LABEL);
} else {
// When there is an IPv4 address, drop unicast/broadcast requests
// and broadcast replies with a different target IPv4 address.
gen.addLoadImmediate(Register.R0, ARP_TARGET_IP_ADDRESS_OFFSET);
gen.addJumpIfBytesNotEqual(Register.R0, mIPv4Address, gen.DROP_LABEL);
}
// Otherwise, pass
gen.addJump(gen.PASS_LABEL);
}

100
services/tests/servicestests/src/android/net/apf/ApfTest.java
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@@ -580,7 +580,7 @@ public class ApfTest extends AndroidTestCase {
public TestApfFilter(IpManager.Callback ipManagerCallback, boolean multicastFilter,
IpConnectivityLog log) throws Exception {
super(new ApfCapabilities(2, 1000, ARPHRD_ETHER), NetworkInterface.getByName("lo"),
super(new ApfCapabilities(2, 1536, ARPHRD_ETHER), NetworkInterface.getByName("lo"),
ipManagerCallback, multicastFilter, log);
}
@@ -618,6 +618,7 @@ public class ApfTest extends AndroidTestCase {
}
private static final int ETH_HEADER_LEN = 14;
private static final int ETH_DEST_ADDR_OFFSET = 0;
private static final int ETH_ETHERTYPE_OFFSET = 12;
private static final byte[] ETH_BROADCAST_MAC_ADDRESS = new byte[]{
(byte) 0xff, (byte) 0xff, (byte) 0xff, (byte) 0xff, (byte) 0xff, (byte) 0xff };
@@ -676,9 +677,18 @@ public class ApfTest extends AndroidTestCase {
4, // Protocol size: 4
0, 1 // Opcode: request (1)
};
private static final byte[] ARP_IPV4_REPLY_HEADER = new byte[]{
0, 1, // Hardware type: Ethernet (1)
8, 0, // Protocol type: IP (0x0800)
6, // Hardware size: 6
4, // Protocol size: 4
0, 2 // Opcode: reply (2)
};
private static final int ARP_TARGET_IP_ADDRESS_OFFSET = ETH_HEADER_LEN + 24;
private static final byte[] MOCK_IPV4_ADDR = new byte[]{10, 0, 0, 1};
private static final byte[] ANOTHER_IPV4_ADDR = new byte[]{10, 0, 0, 2};
private static final byte[] IPV4_ANY_HOST_ADDR = new byte[]{0, 0, 0, 0};
@LargeTest
public void testApfFilterIPv4() throws Exception {
@@ -801,51 +811,81 @@ public class ApfTest extends AndroidTestCase {
apfFilter.shutdown();
}
private void verifyArpFilter(MockIpManagerCallback ipManagerCallback, ApfFilter apfFilter,
LinkProperties linkProperties, int filterResult) {
ipManagerCallback.resetApfProgramWait();
apfFilter.setLinkProperties(linkProperties);
byte[] program = ipManagerCallback.getApfProgram();
ByteBuffer packet = ByteBuffer.wrap(new byte[100]);
packet.putShort(ETH_ETHERTYPE_OFFSET, (short)ETH_P_ARP);
assertPass(program, packet.array(), 0);
packet.position(ARP_HEADER_OFFSET);
packet.put(ARP_IPV4_REQUEST_HEADER);
assertVerdict(filterResult, program, packet.array(), 0);
packet.position(ARP_TARGET_IP_ADDRESS_OFFSET);
packet.put(MOCK_IPV4_ADDR);
assertPass(program, packet.array(), 0);
private byte[] getProgram(MockIpManagerCallback cb, ApfFilter filter, LinkProperties lp) {
cb.resetApfProgramWait();
filter.setLinkProperties(lp);
return cb.getApfProgram();
}
private void verifyArpFilter(byte[] program, int filterResult) {
// Verify ARP request packet
assertPass(program, arpRequestBroadcast(MOCK_IPV4_ADDR), 0);
assertVerdict(filterResult, program, arpRequestBroadcast(ANOTHER_IPV4_ADDR), 0);
assertDrop(program, arpRequestBroadcast(IPV4_ANY_HOST_ADDR), 0);
// Verify unicast ARP reply packet is always accepted.
assertPass(program, arpReplyUnicast(MOCK_IPV4_ADDR), 0);
assertPass(program, arpReplyUnicast(ANOTHER_IPV4_ADDR), 0);
assertPass(program, arpReplyUnicast(IPV4_ANY_HOST_ADDR), 0);
// Verify GARP reply packets are always filtered
assertDrop(program, garpReply(), 0);
}
@LargeTest
public void testApfFilterArp() throws Exception {
MockIpManagerCallback ipManagerCallback = new MockIpManagerCallback();
ApfFilter apfFilter = new TestApfFilter(ipManagerCallback, ALLOW_MULTICAST, mLog);
byte[] program = ipManagerCallback.getApfProgram();
// Verify initially ARP filter is off
ByteBuffer packet = ByteBuffer.wrap(new byte[100]);
packet.putShort(ETH_ETHERTYPE_OFFSET, (short)ETH_P_ARP);
assertPass(program, packet.array(), 0);
packet.position(ARP_HEADER_OFFSET);
packet.put(ARP_IPV4_REQUEST_HEADER);
assertPass(program, packet.array(), 0);
packet.position(ARP_TARGET_IP_ADDRESS_OFFSET);
packet.put(MOCK_IPV4_ADDR);
assertPass(program, packet.array(), 0);
// Verify initially ARP request filter is off, and GARP filter is on.
verifyArpFilter(ipManagerCallback.getApfProgram(), PASS);
// Inform ApfFilter of our address and verify ARP filtering is on
LinkAddress linkAddress = new LinkAddress(InetAddress.getByAddress(MOCK_IPV4_ADDR), 24);
LinkProperties lp = new LinkProperties();
assertTrue(lp.addLinkAddress(
new LinkAddress(InetAddress.getByAddress(MOCK_IPV4_ADDR), 24)));
verifyArpFilter(ipManagerCallback, apfFilter, lp, DROP);
assertTrue(lp.addLinkAddress(linkAddress));
verifyArpFilter(getProgram(ipManagerCallback, apfFilter, lp), DROP);
// Inform ApfFilter of loss of IP and verify ARP filtering is off
verifyArpFilter(ipManagerCallback, apfFilter, new LinkProperties(), PASS);
verifyArpFilter(getProgram(ipManagerCallback, apfFilter, new LinkProperties()), PASS);
apfFilter.shutdown();
}
private static byte[] arpRequestBroadcast(byte[] tip) {
ByteBuffer packet = ByteBuffer.wrap(new byte[100]);
packet.putShort(ETH_ETHERTYPE_OFFSET, (short)ETH_P_ARP);
packet.position(ETH_DEST_ADDR_OFFSET);
packet.put(ETH_BROADCAST_MAC_ADDRESS);
packet.position(ARP_HEADER_OFFSET);
packet.put(ARP_IPV4_REQUEST_HEADER);
packet.position(ARP_TARGET_IP_ADDRESS_OFFSET);
packet.put(tip);
return packet.array();
}
private static byte[] arpReplyUnicast(byte[] tip) {
ByteBuffer packet = ByteBuffer.wrap(new byte[100]);
packet.putShort(ETH_ETHERTYPE_OFFSET, (short)ETH_P_ARP);
packet.position(ARP_HEADER_OFFSET);
packet.put(ARP_IPV4_REPLY_HEADER);
packet.position(ARP_TARGET_IP_ADDRESS_OFFSET);
packet.put(tip);
return packet.array();
}
private static byte[] garpReply() {
ByteBuffer packet = ByteBuffer.wrap(new byte[100]);
packet.putShort(ETH_ETHERTYPE_OFFSET, (short)ETH_P_ARP);
packet.position(ETH_DEST_ADDR_OFFSET);
packet.put(ETH_BROADCAST_MAC_ADDRESS);
packet.position(ARP_HEADER_OFFSET);
packet.put(ARP_IPV4_REPLY_HEADER);
packet.position(ARP_TARGET_IP_ADDRESS_OFFSET);
packet.put(IPV4_ANY_HOST_ADDR);
return packet.array();
}
// Verify that the last program pushed to the IpManager.Callback properly filters the
// given packet for the given lifetime.
private void verifyRaLifetime(MockIpManagerCallback ipManagerCallback, ByteBuffer packet,