RFR: 8331682: Slow networks/Impatient clients can potentially send unencrypted TLSv1.3 alerts that won't parse on the server [v24]

[Xue-Lei Andrew Fan]

On Fri, 25 Oct 2024 13:30:43 GMT, Artur Barashev <abarashev at openjdk.org> wrote:

>> Check for unexpected plaintext alert message during TLSv1.3 handshake. This can happen if client doesn't receive ServerHello due to network timeout and tries to close the connection by sending an alert message.
>
> Artur Barashev has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 28 additional commits since the last revision:
> 
>  - Merge branch 'master' into JDK-8331682
>  - Use more appropriate exception with the alert description
>  - Update Copyright
>  - Update @library directive
>  - Merge branch 'master' into JDK-8331682
>  - Produce appropriate exception message. Update tests.
>  - Adjust line length
>  - Additional error checking
>  - Write and read to/from server in a single pass. Use SocketChannel.
>  - Return null if there is no record we attempted to decode
>  - ... and 18 more: https://git.openjdk.org/jdk/compare/878c32d5...aef08dd0

src/java.base/share/classes/sun/security/ssl/SSLCipher.java line 1866:

> 1864:                         // In TLSv1.3 alert level can be ignored, we only get the alert.
> 1865:                         final String msg = "Unexpected plaintext alert received: "
> 1866:                                 + Alert.nameOf(bb.get(bb.position() + 1));

. I would also check the bb size, in case of IndexOutOfBoundsException.
. I may also dump the alert level.
. It may be not a plaintext alert.  From the context, I don't think we are sure of it.

Considering above, I may just dump the hex bytes for the remaining bytes in bb.  For example:
   "Unexpected alert message received [hex bytes]"

src/java.base/share/classes/sun/security/ssl/SSLCipher.java line 1870:

> 1868:                         if (SSLLogger.isOn && SSLLogger.isOn("ssl")) {
> 1869:                             SSLLogger.info(msg);
> 1870:                         }

It may not need the log any longer because the follow-up exception will cover the information.

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PR Review Comment: https://git.openjdk.org/jdk/pull/21043#discussion_r1817323196
PR Review Comment: https://git.openjdk.org/jdk/pull/21043#discussion_r1817323803