Switch back to Xerial Snappy Library

[ajsutton]

PR description

The iq80 Snappy library has insufficient bounds checking resulting in errors like:

2018-11-20 06:57:16.308+10:00 | nioEventLoopGroup-3-1 | ERROR | DeFramer | Exception while processing incoming message
io.netty.handler.codec.DecoderException: java.lang.ArrayIndexOutOfBoundsException: 2
        at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:459) ~[netty-codec-4.1.15.Final.jar:4.1.15.Final]
        at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:265) ~[netty-codec-4.1.15.Final.jar:4.1.15.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-transport-4.1.15.Final.jar:4.1.15.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-transport-4.1.15.Final.jar:4.1.15.Final]
        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) [netty-transport-4.1.15.Final.jar:4.1.15.Final]
        at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1359) [netty-transport-4.1.15.Final.jar:4.1.15.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-transport-4.1.15.Final.jar:4.1.15.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-transport-4.1.15.Final.jar:4.1.15.Final]
        at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:935) [netty-transport-4.1.15.Final.jar:4.1.15.Final]
        at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:134) [netty-transport-4.1.15.Final.jar:4.1.15.Final]
        at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:645) [netty-transport-4.1.15.Final.jar:4.1.15.Final]
        at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:580) [netty-transport-4.1.15.Final.jar:4.1.15.Final]
        at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:497) [netty-transport-4.1.15.Final.jar:4.1.15.Final]
        at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:459) [netty-transport-4.1.15.Final.jar:4.1.15.Final]
        at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:858) [netty-common-4.1.15.Final.jar:4.1.15.Final]
        at io.netty.util.concurrent.DefaultThreadFactory$DefaultRunnableDecorator.run(DefaultThreadFactory.java:138) [netty-common-4.1.15.Final.jar:4.1.15.Final]
        at java.lang.Thread.run(Thread.java:745) [?:1.8.0_25]
Caused by: java.lang.ArrayIndexOutOfBoundsException: 2
        at org.iq80.snappy.SnappyDecompressor.readUncompressedLength(SnappyDecompressor.java:416) ~[snappy-0.4.jar:?]
        at org.iq80.snappy.SnappyDecompressor.getUncompressedLength(SnappyDecompressor.java:31) ~[snappy-0.4.jar:?]
        at org.iq80.snappy.Snappy.getUncompressedLength(Snappy.java:79) ~[snappy-0.4.jar:?]
        at tech.pegasys.pantheon.ethereum.p2p.rlpx.framing.SnappyCompressor.uncompressedLength(SnappyCompressor.java:38) ~[pantheon-p2p-0.9.0-SNAPSHOT.jar:0.9.0-dev-c8549bdc]
        at tech.pegasys.pantheon.ethereum.p2p.rlpx.framing.Framer.processFrame(Framer.java:259) ~[pantheon-p2p-0.9.0-SNAPSHOT.jar:0.9.0-dev-c8549bdc]
        at tech.pegasys.pantheon.ethereum.p2p.rlpx.framing.Framer.deframe(Framer.java:155) ~[pantheon-p2p-0.9.0-SNAPSHOT.jar:0.9.0-dev-c8549bdc]
        at tech.pegasys.pantheon.ethereum.p2p.netty.DeFramer.decode(DeFramer.java:69) ~[pantheon-p2p-0.9.0-SNAPSHOT.jar:0.9.0-dev-c8549bdc]
        at io.netty.handler.codec.ByteToMessageDecoder.decodeRemovalReentryProtection(ByteToMessageDecoder.java:489) ~[netty-codec-4.1.15.Final.jar:4.1.15.Final]
        at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:428) ~[netty-codec-4.1.15.Final.jar:4.1.15.Final]
        ... 16 more

The issue that previously caused us to switch libraries (#251) was because the incoming message was invalid and our error handling has been improved to reduce the noise in that case. As a result we can switch back to the more reliable xerial Snappy library.

Fixed Issue(s)

[CjHare]

LGTM