RFR (S): JDK-8149169 - SSLSocketInputRecord.decodeInputRecord buffer overflow

Fri Mar 18 09:33:32 UTC 2016

Sorry, forgot the new webrev:
http://cr.openjdk.java.net/~clanger/webrevs/8149169.2/


> -----Original Message-----
> From: Langer, Christoph
> Sent: Freitag, 18. März 2016 10:29
> To: 'Xuelei Fan' <xuelei.fan at oracle.com>
> Cc: security-dev at openjdk.java.net
> Subject: RE: RFR (S): JDK-8149169 - SSLSocketInputRecord.decodeInputRecord
> buffer overflow
> 
> Hi Xuelei,
> 
> thanks for your feedback. I tried to address all your points and made the test
> case more robust.
> 
> For SSLSocketImpl I also took the chance to remove 2 unused fields, hope that's
> ok. And I put the buffer length check in the block of handling non null buffer
> input.
> 
> If you are satisfied with my adaptions, it would be great if you could push the
> change for me as I'm no committer yet.
> 
> Thanks & Best regards
> Christoph
> 
> > -----Original Message-----
> > From: security-dev [mailto:security-dev-bounces at openjdk.java.net] On
> Behalf
> > Of Xuelei Fan
> > Sent: Freitag, 18. März 2016 03:52
> > To: security-dev at openjdk.java.net
> > Subject: Re: RFR (S): JDK-8149169 - SSLSocketInputRecord.decodeInputRecord
> > buffer overflow
> >
> > Hi Christoph,
> >
> > Thank you for taking care of this issue.  Some minor comments:
> >
> > SSLSocketImpl.java
> > ------------------
> > 1012    if (buffer != null && (buffer.limit() <
> > inputRecord.bytesInCompletePacket(sockInput)))
> > 1013         return 0;
> >
> > 1. It would be nice to keep the line less than 80 characters.
> > 2. In general, braces ('{' and '}') should always be used for 'if'
> > statement.
> > 3. It is safer to replace buffer.limit() with buffer.remaining().
> >
> > LargePacketAfterHandshakeTest.java
> > ----------------------------------
> > See #1, too.
> >
> > 4. The client thread may try to connect to server before server ready.
> > As may result in intermittent failure.
> >
> > In the template, test/javax/net/ssl/templates/SSLSocketTemplate.java, a
> > serverReady variable is used to keep the pace of client and server.
> > Just for your reference.
> >
> > Thanks,
> > Xuelei
> >
> > On 3/17/2016 5:28 AM, Langer, Christoph wrote:
> > > Hi,
> > >
> > >
> > >
> > > I think I've found a way to fix the issue which looks quite reasonable
> > > to me. Would you please comment/review it? I've also included a test to
> > > reproduce the issue.
> > >
> > >
> > >
> > > Webrev:http://cr.openjdk.java.net/~clanger/webrevs/8149169.1/
> > >
> > > Bug: https://bugs.openjdk.java.net/browse/JDK-8149169
> > >
> > >
> > >
> > > Thanks and best regards
> > >
> > > Christoph
> > >
> > >
> > >
> > > *From:*Langer, Christoph
> > > *Sent:* Dienstag, 15. März 2016 23:00
> > > *To:* security-dev at openjdk.java.net
> > > *Subject:* Regarding JDK-8149169 -
> > > SSLSocketInputRecord.decodeInputRecord buffer overflow
> > >
> > >
> > >
> > > Hi there,
> > >
> > >
> > >
> > > today I did some debugging regarding the TLS exception I've seen and
> > > reported in JDK-8149169:
> > >
> > >
> > >
> > > javax.net.ssl.SSLException: java.nio.BufferOverflowException
> > >         at sun.security.ssl.Alerts.getSSLException(Alerts.java:214)
> > >         at sun.security.ssl.SSLSocketImpl.fatal(SSLSocketImpl.java:1948)
> > >         at sun.security.ssl.SSLSocketImpl.fatal(SSLSocketImpl.java:1900)
> > >         at
> > > sun.security.ssl.SSLSocketImpl.handleException(SSLSocketImpl.java:1883)
> > >         at
> > > sun.security.ssl.SSLSocketImpl.handleException(SSLSocketImpl.java:1809)
> > >         at sun.security.ssl.AppInputStream.read(AppInputStream.java:173)
> > >         at java.io.BufferedInputStream.fill(BufferedInputStream.java:246)
> > >         at java.io.BufferedInputStream.read1(BufferedInputStream.java:286)
> > >         at java.io.BufferedInputStream.read(BufferedInputStream.java:345)
> > >         at
> > > sun.net.www.http.HttpClient.parseHTTPHeader(HttpClient.java:704)
> > > <http://www.http.HttpClient.parseHTTPHeader%28HttpClient.java:704%29>
> > >         at sun.net.www.http.HttpClient.parseHTTP(HttpClient.java:647)
> > > <http://www.http.HttpClient.parseHTTP%28HttpClient.java:647%29>
> > >         at sun.net.www.http.HttpClient.parseHTTP(HttpClient.java:675)
> > > <http://www.http.HttpClient.parseHTTP%28HttpClient.java:675%29>
> > >         at
> > >
> >
> sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConne
> > ction.java:1534)
> > >
> >
> <http://www.protocol.http.HttpURLConnection.getInputStream0%28HttpURLCo
> > nnection.java:1534%29>
> > >         at
> > >
> >
> sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnec
> > tion.java:1439)
> > >
> >
> <http://www.protocol.http.HttpURLConnection.getInputStream%28HttpURLCon
> > nection.java:1439%29>
> > >         at
> > >
> java.net.HttpURLConnection.getResponseCode(HttpURLConnection.java:480)
> > >         at
> > >
> >
> sun.net.www.protocol.https.HttpsURLConnectionImpl.getResponseCode(HttpsU
> > RLConnectionImpl.java:319)
> > >
> >
> <http://www.protocol.https.HttpsURLConnectionImpl.getResponseCode%28Http
> > sURLConnectionImpl.java:319%29>
> > >
> > >         at
> > >
> >
> com.sap.cl.HttpsURLConnectionTest.sendGETRequest(HttpsURLConnectionTest.j
> > ava:42)
> > >
> > >         at
> > > com.sap.cl.HttpsURLConnectionTest.main(HttpsURLConnectionTest.java:63)
> > > Caused by: java.nio.BufferOverflowException
> > >         at java.nio.HeapByteBuffer.put(HeapByteBuffer.java:206)
> > >         at
> > >
> >
> sun.security.ssl.SSLSocketInputRecord.decodeInputRecord(SSLSocketInputRecor
> > d.java:226)
> > >
> > >         at
> > >
> sun.security.ssl.SSLSocketInputRecord.decode(SSLSocketInputRecord.java:178)
> > >         at
> > > sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:1012)
> > >         at
> > > sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:957)
> > >         at sun.security.ssl.AppInputStream.read(AppInputStream.java:159)
> > >         ... 12 more
> > >
> > >
> > >
> > > I think the problem is with the logic in
> > > sun.security.ssl.AppInputStream. read(byte[] b, int off, int len). The
> > > read method calls the readRecord(buffer) method of the socket
> > > (SSLSocketImpl) and hands it the buffer to be eventually filled by
> > > SSLSocketInputRecord.decodeInputRecord(). The buffer is initialized with
> > > 4K and before readRecord is called, the packet length is verified (in
> > > line 144: int packetLen = socket.bytesInCompletePacket();) and the
> > > buffer reallocated if the incoming package would be larger than the
> > > buffer. However, in my case, the incoming package is a handshake package
> > > of a small size, so the buffer won't be adjusted. Then, after the
> > > handshake is done, the real data packet is read, still within
> > > SSLSocketImpl.readRecord() (e.g. line 1012 of SSLSocketImpl) and this
> > > one has a length of more than 4K. So the buffer will be too small in
> > > decodeInputRecord and hence the exception is thrown.
> > >
> > >
> > >
> > > So, basically the issue will appear if the TLS data package following
> > > immediately after a server initiated handshake will be larger than the
> > > buffer of AppInputStream. I guess that should be easily recreatable in a
> > > small test case.
> > >
> > >
> > >
> > > Now the question how to fix? I can see 3 options:
> > >
> > > a)      Just allocate the ByteBuffer in AppInputStream to
> > > SSLRecord.maxLargeRecordSize (about 32K) - easiest fix and removing the
> > > need to check the length for each record. But I guess this is not
> > > desired as the buffer is unnecessarily large for most cases?
> > >
> > > b)      Extend SSLSocketInputRecord somehow to be able to not only read
> > > the length of the incoming packet but also the type, e.g. if it is a
> > > handshake. In that case the buffer would need to be extended to
> > > SSLRecord.maxLargeRecordSize. But why not do a) then??
> > >
> > > c)       Check the volume bytes returned from readRecord and redo the
> > > read in case the volume is larger than the buffer capacity
> > >
> > >
> > >
> > > Which way should I pursue? Do you see another option? Or am I getting
> > > something completely wrong running into an illegal case?
> > >
> > >
> > >
> > > Thanks in advance for your feedback,
> > >
> > > Christoph
> > >
> > >
> > >