[http-client-cio] Responses with more than 2048 characters in header result in IndexOutOfBoundsException

[trathschlag]

Hello everybody,
I ran into a problem with the CIO HTTP-Client when getting responses where the HTTP header exceeds 2048 characters:

java.lang.IndexOutOfBoundsException: null
	at java.nio.Buffer.checkIndex(Buffer.java:540)
	at java.nio.DirectCharBufferS.get(DirectCharBufferS.java:253)
	at io.ktor.http.cio.internals.CharBufferBuilder.getImpl(CharBufferBuilder.kt:21)
	at io.ktor.http.cio.internals.CharBufferBuilder.get(CharBufferBuilder.kt:18)
	at io.ktor.http.cio.internals.CharBufferBuilder.charAt(CharBufferBuilder.kt:6)
	at io.ktor.http.cio.internals.TokenizerKt.findColonOrSpace(Tokenizer.kt:68)
	at io.ktor.http.cio.HttpParserKt.parseHeaders(HttpParser.kt:81)
	at io.ktor.http.cio.HttpParserKt.parseResponse(HttpParser.kt:54)
	at io.ktor.http.cio.HttpParserKt$parseResponse$1.doResume(HttpParser.kt)
	at kotlin.coroutines.experimental.jvm.internal.CoroutineImpl.resume(CoroutineImpl.kt:54)
	at kotlin.coroutines.experimental.jvm.internal.CoroutineImpl.resume(CoroutineImpl.kt:53)
	at kotlin.coroutines.experimental.jvm.internal.CoroutineImpl.resume(CoroutineImpl.kt:53)
	at kotlinx.coroutines.experimental.DispatchedTask$DefaultImpls.run(Dispatched.kt:161)
	at kotlinx.coroutines.experimental.io.internal.MutableDelegateContinuation.run(MutableDelegateContinuation.kt:14)
	at io.ktor.network.util.IOCoroutineDispatcher$IODispatchedTask.run(IOCoroutineDispatcher.kt)
	at io.ktor.network.util.IOCoroutineDispatcher$IOThread$run$1.doResume(IOCoroutineDispatcher.kt:78)
	at kotlin.coroutines.experimental.jvm.internal.CoroutineImpl.resume(CoroutineImpl.kt:54)
	at kotlinx.coroutines.experimental.DispatchedTask$DefaultImpls.run(Dispatched.kt:161)
	at kotlinx.coroutines.experimental.DispatchedContinuation.run(Dispatched.kt:25)
	at kotlinx.coroutines.experimental.EventLoopBase.processNextEvent(EventLoop.kt:147)
	at kotlinx.coroutines.experimental.BlockingCoroutine.joinBlocking(Builders.kt:244)
	at kotlinx.coroutines.experimental.BuildersKt.runBlocking(Builders.kt:185)
	at io.ktor.network.util.IOCoroutineDispatcher$IOThread.run(IOCoroutineDispatcher.kt:73)

The problem seems to be, that in CharBuffersBuilder the CHAR_BUFFER_SIZE from CharBufferPool is used mutliple times for offset calculation. As it turns out, this constant holds the size of the CharBuffer in bytes while the CharBuffer itself uses 16-bit characters. The code assumes the CharBuffer to be able to hold 4096 characters but this is acutally the size in bytes and the CharBuffer is only 2048 characters big. After reading 2048 characters from a response with a long header section, the code crashes.

[e5l]

Thnx for the report, there is a bug here. WIP