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Commit a3621386 authored by Paul Jensen's avatar Paul Jensen Committed by Erik Kline
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Sanity check ICMP6 router advertisement packets 

There is a chance a packet can slip by before we install the filter
on our socket listening for RAs, so add some basic sanity checking
to make sure we've recieved an RA.

Change-Id: I14cf84a0814896a41e00f50af376dfc4988d36cb
Fixes: 29586253
parent 8eaa65b8

services/net/java/android/net/apf/ApfFilter.java

+15 −1
Original line number Diff line number Diff line
@@ -131,6 +131,7 @@ public class ApfFilter { 


    private static final int ICMP6_TYPE_OFFSET = ETH_HEADER_LEN + IPV6_HEADER_LEN;

    private static final int ICMP6_NEIGHBOR_ANNOUNCEMENT = 136;

    private static final int ICMP6_ROUTER_ADVERTISEMENT = 134;



    // NOTE: this must be added to the IPv4 header length in IPV4_HEADER_SIZE_MEMORY_SLOT

    private static final int UDP_DESTINATION_PORT_OFFSET = ETH_HEADER_LEN + 2;
@@ -306,7 +307,11 @@ public class ApfFilter { 
        }



        private long uint32(int s) {

            return s & 0xffffffff;

            return s & 0xffffffffL;

        }



        private long getUint16(ByteBuffer buffer, int position) {

            return uint16(buffer.getShort(position));

        }



        private void prefixOptionToString(StringBuffer sb, int offset) {
@@ -375,6 +380,15 @@ public class ApfFilter { 
            mPacket.clear();

            mLastSeen = curTime();



            // Sanity check packet in case a packet arrives before we attach RA filter

            // to our packet socket. b/29586253

            if (getUint16(mPacket, ETH_ETHERTYPE_OFFSET) != ETH_P_IPV6 ||

                    uint8(mPacket.get(IPV6_NEXT_HEADER_OFFSET)) != IPPROTO_ICMPV6 ||

                    uint8(mPacket.get(ICMP6_TYPE_OFFSET)) != ICMP6_ROUTER_ADVERTISEMENT) {

                throw new IllegalArgumentException("Not an ICMP6 router advertisement");

            }





            // Ignore the checksum.

            int lastNonLifetimeStart = addNonLifetime(0,

                    ICMP6_RA_CHECKSUM_OFFSET,