DHCP: Don't write options longer than 255 bytes. (06ac4b8d) · Commits · e / os / android_frameworks_base

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

+23 −14

Original line number	Diff line number	Diff line
		@@ -7,6 +7,7 @@ import android.os.Build;
		import android.os.SystemProperties;
		import android.system.OsConstants;

		import java.io.UnsupportedEncodingException;
		import java.net.Inet4Address;
		import java.net.UnknownHostException;
		import java.nio.BufferUnderflowException;
		@@ -48,6 +49,7 @@ abstract class DhcpPacket {
		public static final int MIN_PACKET_LENGTH_L3 = MIN_PACKET_LENGTH_BOOTP + 20 + 8;
		public static final int MIN_PACKET_LENGTH_L2 = MIN_PACKET_LENGTH_L3 + 14;

		public static final int MAX_OPTION_LEN = 255;
		/**
		* IP layer definitions.
		*/
		@@ -468,6 +470,10 @@ abstract class DhcpPacket {
		*/
		protected static void addTlv(ByteBuffer buf, byte type, byte[] payload) {
		if (payload != null) {
		if (payload.length > MAX_OPTION_LEN) {
		throw new IllegalArgumentException("DHCP option too long: "
		+ payload.length + " vs. " + MAX_OPTION_LEN);
		}
		buf.put(type);
		buf.put((byte) payload.length);
		buf.put(payload);
		@@ -487,15 +493,21 @@ abstract class DhcpPacket {
		* Adds an optional parameter containing a list of IP addresses.
		*/
		protected static void addTlv(ByteBuffer buf, byte type, List<Inet4Address> addrs) {
		if (addrs != null && addrs.size() > 0) {
		if (addrs == null \|\| addrs.size() == 0) return;

		int optionLen = 4 * addrs.size();
		if (optionLen > MAX_OPTION_LEN) {
		throw new IllegalArgumentException("DHCP option too long: "
		+ optionLen + " vs. " + MAX_OPTION_LEN);
		}

		buf.put(type);
		buf.put((byte)(4 * addrs.size()));
		buf.put((byte)(optionLen));

		for (Inet4Address addr : addrs) {
		buf.put(addr.getAddress());
		}
		}
		}

		/**
		* Adds an optional parameter containing a short integer
		@@ -520,16 +532,13 @@ abstract class DhcpPacket {
		}

		/**
		* Adds an optional parameter containing and ASCII string.
		* Adds an optional parameter containing an ASCII string.
		*/
		protected static void addTlv(ByteBuffer buf, byte type, String str) {
		if (str != null) {
		buf.put(type);
		buf.put((byte) str.length());

		for (int i = 0; i < str.length(); i++) {
		buf.put((byte) str.charAt(i));
		}
		try {
		addTlv(buf, type, str.getBytes("US-ASCII"));
		} catch (UnsupportedEncodingException e) {
		throw new IllegalArgumentException("String is not US-ASCII: " + str);
		}
		}