Add Support for Kerberos auth for proxies in Netty - #7276
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* Initial support for Kerberos auth This commit adds - A new enum `ProxyAuthScheme` that enumerates the proxy auth mechanisms supported by Netty - `ProxyAuthGenerator` (internal) that knows how to generate the auth params for its respective auth scheme - `NegotiateProxyAuthGenerator` for Kerberos * wip * Document OID
This reverts commit b20454f.
* Add basic auth impl * Checkstyle and dependency issues
* Switch to AuthGenerator in tunnel pool Use the new AuthGenerator mechanism in the `Http1TunnelConnectionPool` and `AwaitCloseChannelPoolMap` classes. For now, supports only using BASIC auth; Kerberos will be added in a subsequent PR. * Allow empty username, pass Original impl allowed empty (e.g. whitespace) in username and pass for BASIC auth so preserve that behavior.
* Support ProxyAuthScheme This commit Adds a `ProxyAuthScheme` configuration option in `ProxyConfiguration` and adds support for `NEGOTIATE` auth scheme. For backwards compatibility, if username and password are set on the config and the proxy auth scheme is *not* set, the client assumes `BASIC` auth scheme. If `NEGOTIATE` is configured, `username` and `password` are ignored. * Fix test
requestMutualAuth(true) asked for mutual authentication that was never
established: the proxy's response token is never consumed, so there is
nothing to verify it against. Preemptive single-leg Negotiate cannot
verify it either, so the call is dropped rather than wired up.
The com.sun.security.auth.module.Krb5LoginModule import existed only to
satisfy a javadoc {@link}. Referring to the class by name in {@code}
instead keeps the documentation while dropping a compile-time reference
to a JDK-implementation-specific class.
* Document the Negotiate proxy auth prerequisites NEGOTIATE depends on ambient, expiring, host-level state rather than on anything the customer passes to the builder, and none of that was documented. Spell out on the enum constant that credentials come from the ticket cache and never from a prompt or keytab, that a missing or expired ticket is not detected at build time and instead fails when a proxy connection is established, that the service principal is derived from the configured proxy host so an IP literal will not work, and that the JDK's GSS and JAAS modules must be present in the runtime image. Also note on the builder setter that username and password are ignored for NEGOTIATE, so credentials left in place while switching schemes are not silently assumed to be in use. * Warn when proxy credentials are ignored by NEGOTIATE NEGOTIATE authenticates from the Kerberos ticket cache, so a username and password configured alongside it are dead configuration. Switching an existing Basic proxy configuration over to NEGOTIATE and leaving the credentials in place therefore looks like it still uses them, with no signal either way. Warn at build() rather than reject, and only when the credentials were set directly on the builder: values resolved from system properties or environment variables may not be under the caller's control, so warning about those would be noise they cannot act on.
Generating a SPNEGO token performs a JAAS login and may make a blocking TGS request to the KDC. That ran on the Netty event loop during proxy tunnel setup, so a slow or unreachable KDC stalled every other channel assigned to that loop, and SDK timeouts could not unpark the thread. ProxyAuthGenerator now returns a CompletableFuture, so the contract states that generating params may be slow and must not complete on the caller's thread. Basic auth completes inline and stays on the existing synchronous path; the handler only hops threads when the future is not already done. AwaitCloseChannelPoolMap creates the executor the Negotiate generator runs on, and shuts it down when it closes, so the resource is created and released in the same place. It is a single daemon thread, created only when NEGOTIATE is configured: the goal is to keep blocking work off the event loops, not to parallelize it. The generator itself is resolved once per client rather than once per remote host.
dagnir
changed the title
Per team review, this makes more sense in the SPI package where it can be shared by other client implementations.
dagnir
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RanVaknin
approved these changes
Aug 20, 2026
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Motivation and Context
Add support for Kerberos (SPNEGO) proxy authentication via the new
proxyAuthSchemeoption on the Netty client'sProxyConfiguration. SettingProxyAuthScheme.NEGOTIATEauthenticates proxy CONNECT tunnels using the Kerberos ticket cache in the environment; a valid ticket-granting ticket must already exist (for example viakinit), and no password or keytab is read.ProxyAuthScheme.BASICmay also be set to select Basic authentication explicitly. See #7033.This branch is a collection of smaller PRs that were previously reviewed:
NEGOTIATEusage #7285Modifications
Testing
Screenshots (if appropriate)
Types of changes
Checklist
mvn installsucceedsscripts/new-changescript and following the instructions. Commit the new file created by the script in.changes/next-releasewith your changes.License