Merge "Deal with null characters in string options." (25e9d87b) · Commits · e / os / android_frameworks_base

services/net/java/android/net/dhcp/DhcpPacket.java

+18 −6

Original line number	Diff line number	Diff line
		@@ -611,10 +611,22 @@ abstract class DhcpPacket {
		/**
		* Reads a string of specified length from the buffer.
		*/
		private static String readAsciiString(ByteBuffer buf, int byteCount) {
		private static String readAsciiString(ByteBuffer buf, int byteCount, boolean nullOk) {
		byte[] bytes = new byte[byteCount];
		buf.get(bytes);
		return new String(bytes, 0, bytes.length, StandardCharsets.US_ASCII);
		int length = bytes.length;
		if (!nullOk) {
		// Stop at the first null byte. This is because some DHCP options (e.g., the domain
		// name) are passed to netd via FrameworkListener, which refuses arguments containing
		// null bytes. We don't do this by default because vendorInfo is an opaque string which
		// could in theory contain null bytes.
		for (length = 0; length < bytes.length; length++) {
		if (bytes[length] == 0) {
		break;
		}
		}
		}
		return new String(bytes, 0, length, StandardCharsets.US_ASCII);
		}

		/**
		@@ -797,7 +809,7 @@ abstract class DhcpPacket {
		break;
		case DHCP_HOST_NAME:
		expectedLen = optionLen;
		hostName = readAsciiString(packet, optionLen);
		hostName = readAsciiString(packet, optionLen, false);
		break;
		case DHCP_MTU:
		expectedLen = 2;
		@@ -805,7 +817,7 @@ abstract class DhcpPacket {
		break;
		case DHCP_DOMAIN_NAME:
		expectedLen = optionLen;
		domainName = readAsciiString(packet, optionLen);
		domainName = readAsciiString(packet, optionLen, false);
		break;
		case DHCP_BROADCAST_ADDRESS:
		bcAddr = readIpAddress(packet);
		@@ -834,7 +846,7 @@ abstract class DhcpPacket {
		break;
		case DHCP_MESSAGE:
		expectedLen = optionLen;
		message = readAsciiString(packet, optionLen);
		message = readAsciiString(packet, optionLen, false);
		break;
		case DHCP_MAX_MESSAGE_SIZE:
		expectedLen = 2;
		@@ -850,7 +862,7 @@ abstract class DhcpPacket {
		break;
		case DHCP_VENDOR_CLASS_ID:
		expectedLen = optionLen;
		vendorId = readAsciiString(packet, optionLen);
		vendorId = readAsciiString(packet, optionLen, true);
		break;
		case DHCP_CLIENT_IDENTIFIER: { // Client identifier
		byte[] id = new byte[optionLen];

services/tests/servicestests/Android.mk

+1 −0

Original line number	Diff line number	Diff line
		@@ -10,6 +10,7 @@ LOCAL_SRC_FILES := $(call all-java-files-under, src)
		LOCAL_STATIC_JAVA_LIBRARIES := \
		services.core \
		services.devicepolicy \
		services.net \
		easymocklib \
		guava \
		mockito-target

services/tests/servicestests/src/android/net/dhcp/DhcpPacketTest.java

0 → 100644

+116 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2015 The Android Open Source Project
		*
		* Licensed under the Apache License, Version 2.0 (the "License");
		* you may not use this file except in compliance with the License.
		* You may obtain a copy of the License at
		*
		* http://www.apache.org/licenses/LICENSE-2.0
		*
		* Unless required by applicable law or agreed to in writing, software
		* distributed under the License is distributed on an "AS IS" BASIS,
		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		* See the License for the specific language governing permissions and
		* limitations under the License.
		*/

		package android.net.dhcp;

		import android.net.NetworkUtils;
		import android.system.OsConstants;
		import android.test.suitebuilder.annotation.SmallTest;
		import junit.framework.TestCase;

		import java.net.Inet4Address;
		import java.nio.ByteBuffer;

		import static android.net.dhcp.DhcpPacket.*;


		public class DhcpPacketTest extends TestCase {

		private static Inet4Address SERVER_ADDR =
		(Inet4Address) NetworkUtils.numericToInetAddress("192.0.2.1");
		private static Inet4Address CLIENT_ADDR =
		(Inet4Address) NetworkUtils.numericToInetAddress("192.0.2.234");
		private static byte[] CLIENT_MAC = new byte[] { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05 };

		class TestDhcpPacket extends DhcpPacket {
		private byte mType;
		// TODO: Make this a map of option numbers to bytes instead.
		private byte[] mDomainBytes, mVendorInfoBytes;

		public TestDhcpPacket(byte type, byte[] domainBytes, byte[] vendorInfoBytes) {
		super(0xdeadbeef, INADDR_ANY, CLIENT_ADDR, INADDR_ANY, INADDR_ANY, CLIENT_MAC, true);
		mType = type;
		mDomainBytes = domainBytes;
		mVendorInfoBytes = vendorInfoBytes;
		}

		public ByteBuffer buildPacket(int encap, short unusedDestUdp, short unusedSrcUdp) {
		ByteBuffer result = ByteBuffer.allocate(MAX_LENGTH);
		fillInPacket(encap, CLIENT_ADDR, SERVER_ADDR,
		DHCP_CLIENT, DHCP_SERVER, result, DHCP_BOOTREPLY, false);
		return result;
		}

		public void finishPacket(ByteBuffer buffer) {
		addTlv(buffer, DHCP_MESSAGE_TYPE, mType);
		if (mDomainBytes != null) {
		addTlv(buffer, DHCP_DOMAIN_NAME, mDomainBytes);
		}
		if (mVendorInfoBytes != null) {
		addTlv(buffer, DHCP_VENDOR_CLASS_ID, mVendorInfoBytes);
		}
		addTlvEnd(buffer);
		}

		// Convenience method.
		public ByteBuffer build() {
		// ENCAP_BOOTP packets don't contain ports, so just pass in 0.
		ByteBuffer pkt = buildPacket(ENCAP_BOOTP, (short) 0, (short) 0);
		pkt.flip();
		return pkt;
		}
		}

		private void assertDomainAndVendorInfoParses(
		String expectedDomain, byte[] domainBytes,
		String expectedVendorInfo, byte[] vendorInfoBytes) {
		ByteBuffer packet = new TestDhcpPacket(DHCP_MESSAGE_TYPE_OFFER,
		domainBytes, vendorInfoBytes).build();
		DhcpPacket offerPacket = DhcpPacket.decodeFullPacket(packet, ENCAP_BOOTP);
		assertEquals(expectedDomain, offerPacket.mDomainName);
		assertEquals(expectedVendorInfo, offerPacket.mVendorId);
		}

		@SmallTest
		public void testDomainName() throws Exception {
		byte[] nullByte = new byte[] { 0x00 };
		byte[] twoNullBytes = new byte[] { 0x00, 0x00 };
		byte[] nonNullDomain = new byte[] {
		(byte) 'g', (byte) 'o', (byte) 'o', (byte) '.', (byte) 'g', (byte) 'l'
		};
		byte[] trailingNullDomain = new byte[] {
		(byte) 'g', (byte) 'o', (byte) 'o', (byte) '.', (byte) 'g', (byte) 'l', 0x00
		};
		byte[] embeddedNullsDomain = new byte[] {
		(byte) 'g', (byte) 'o', (byte) 'o', 0x00, 0x00, (byte) 'g', (byte) 'l'
		};
		byte[] metered = "ANDROID_METERED".getBytes("US-ASCII");

		byte[] meteredEmbeddedNull = metered.clone();
		meteredEmbeddedNull[7] = (char) 0;

		byte[] meteredTrailingNull = metered.clone();
		meteredTrailingNull[meteredTrailingNull.length - 1] = (char) 0;

		assertDomainAndVendorInfoParses("", nullByte, "\u0000", nullByte);
		assertDomainAndVendorInfoParses("", twoNullBytes, "\u0000\u0000", twoNullBytes);
		assertDomainAndVendorInfoParses("goo.gl", nonNullDomain, "ANDROID_METERED", metered);
		assertDomainAndVendorInfoParses("goo", embeddedNullsDomain,
		"ANDROID\u0000METERED", meteredEmbeddedNull);
		assertDomainAndVendorInfoParses("goo.gl", trailingNullDomain,
		"ANDROID_METERE\u0000", meteredTrailingNull);
		}
		}