Kerberos

The kerberos package is a C++ extension for Node.js that provides cross-platform support for kerberos authentication using GSSAPI on linux/osx, and SSPI on windows. Much of the code in this module is adapted from ccs-kerberos and winkerberos.

Requirements

Linux

• python v2.7
• make
• A proper C/C++ compiler toolchain, like GCC
• Distribution-specific kerberos packages (e.g. krb5-dev on Ubuntu)

macOS

• Xcode Command Line Tools: Can be installed with xcode-select --install
• Distribution-specific kerberos packages (e.g. krb5 on Homebrew)

Windows

• Option 1: Install all the required tools and configurations using Microsoft's windows-build-tools by running npm install -g windows-build-tools from an elevated PowerShell (run as Administrator).

• Option 2: Install dependencies and configuration manually

  1. Visual C++ Build Environment:
  • Option 1: Install Visual C++ Build Tools using the Default Install option.
  • Option 2: Install Visual Studio 2015 (or modify an existing installation) and select Common Tools for Visual C++ during setup.

  💡 [Windows Vista / 7 only] requires .NET Framework 4.5.1

  2. Install Python 2.7 or Miniconda 2.7 (v3.x.x is not supported), and run npm config set python python2.7
  3. Launch cmd, npm config set msvs_version 2015

MongoDB Node.js Driver Version Compatibility

Only the following version combinations with the MongoDB Node.js Driver are considered stable.

	kerberos@1.x	kerberos@2.x
mongodb@6.x	N/A	✓
mongodb@5.x	✓	✓
mongodb@4.x	✓	✓
mongodb@3.x	✓	N/A

Installation

Now you can install kerberos with the following:

npm install kerberos

Prebuild Platforms

Below are the platforms that are available as prebuilds on each github release. prebuild-install downloads these automatically depending on the platform you are running npm install on.

• Linux GLIBC 2.23 or later
  • s390x
  • arm64
  • x64
• MacOS universal binary
  • x64
  • arm64
• Windows
  • x64

Release Integrity

Releases are created automatically and signed using the Node team's GPG key. This applies to the git tag as well as all release packages provided as part of a GitHub release. To verify the provided packages, download the key and import it using gpg:

gpg --import node-driver.asc

The GitHub release contains a detached signature file for the NPM package (named kerberos-X.Y.Z.tgz.sig).

The following command returns the link npm package.

npm view kerberos@vX.Y.Z dist.tarball 

Using the result of the above command, a curl command can return the official npm package for the release.

To verify the integrity of the downloaded package, run the following command:

gpg --verify kerberos-X.Y.Z.tgz.sig kerberos-X.Y.Z.tgz

Note

No verification is done when using npm to install the package. To ensure release integrity when using npm, download the tarball manually from the GitHub release, verify the signature, then install the package from the downloaded tarball using npm install mongodb-X.Y.Z.tgz.

To verify the native .node packages, follow the same steps as above.

Testing

Run the test suite using:

docker run -i -v PATH_TO_KERBEROS_REPO:/app -w /app -e PROJECT_DIRECTORY=/app ubuntu:20.04 /bin/bash /app/.evergreen/run-tests-ubuntu.sh

NOTE: The test suite requires an active kerberos deployment.

Documentation

Classes

KerberosClient

KerberosServer

Functions

checkPassword(username, password, service, [defaultRealm], [callback]) ⇒ Promise

This function provides a simple way to verify that a user name and password match those normally used for Kerberos authentication. It does this by checking that the supplied user name and password can be used to get a ticket for the supplied service. If the user name does not contain a realm, then the default realm supplied is used.

For this to work properly the Kerberos must be configured properly on this machine. That will likely mean ensuring that the edu.mit.Kerberos preference file has the correct realms and KDCs listed.

IMPORTANT: This method is vulnerable to KDC spoofing attacks and it should only be used for testing. Do not use this in any production system - your security could be compromised if you do.

principalDetails(service, hostname, [callback]) ⇒ Promise

This function returns the service principal for the server given a service type and hostname.

Details are looked up via the /etc/keytab file.

initializeClient(service, [options], [callback]) ⇒ Promise

Initializes a context for client-side authentication with the given service principal.

initializeServer(service, [callback]) ⇒ Promise

Initializes a context for server-side authentication with the given service principal.

KerberosClient

Properties

Name	Type	Description
username	string	The username used for authentication
response	string	The last response received during authentication steps
responseConf	string	Indicates whether confidentiality was applied or not (GSSAPI only)
contextComplete	boolean	Indicates that authentication has successfully completed or not

• KerberosClient

  • .step(challenge, [callback])

  • .wrap(challenge, [options], [callback])

  • .unwrap(challenge, [callback])

kerberosClient.step(challenge, [callback])

Param	Type	Description
challenge	string	A string containing the base64-encoded server data (which may be empty for the first step)
[callback]	function

Processes a single kerberos client-side step using the supplied server challenge.

Returns: Promise - returns Promise if no callback passed

kerberosClient.wrap(challenge, [options], [callback])

Param	Type	Description
challenge	string	The response returned after calling unwrap
[options]	object	Optional settings
[options.user]	string	The user to authorize
[options.protect]	boolean	Indicates if the wrap should request message confidentiality
[callback]	function

Perform the client side kerberos wrap step.

Returns: Promise - returns Promise if no callback passed

kerberosClient.unwrap(challenge, [callback])

Param	Type	Description
challenge	string	A string containing the base64-encoded server data
[callback]	function

Perform the client side kerberos unwrap step

Returns: Promise - returns Promise if no callback passed

KerberosServer

Properties

Name	Type	Description
username	string	The username used for authentication
response	string	The last response received during authentication steps
targetName	string	The target used for authentication
contextComplete	boolean	Indicates that authentication has successfully completed or not

kerberosServer.step(challenge, [callback])

Param	Type	Description
challenge	string	A string containing the base64-encoded client data
[callback]	function

Processes a single kerberos server-side step using the supplied client data.

Returns: Promise - returns Promise if no callback passed

checkPassword(username, password, service, [defaultRealm], [callback])

Param	Type	Description
username	string	The Kerberos user name. If no realm is supplied, then the defaultRealm will be used.
password	string	The password for the user.
service	string	The Kerberos service to check access for.
[defaultRealm]	string	The default realm to use if one is not supplied in the user argument.
[callback]	function

This function provides a simple way to verify that a user name and password match those normally used for Kerberos authentication. It does this by checking that the supplied user name and password can be used to get a ticket for the supplied service. If the user name does not contain a realm, then the default realm supplied is used.

For this to work properly the Kerberos must be configured properly on this machine. That will likely mean ensuring that the edu.mit.Kerberos preference file has the correct realms and KDCs listed.

IMPORTANT: This method is vulnerable to KDC spoofing attacks and it should only be used for testing. Do not use this in any production system - your security could be compromised if you do.

Returns: Promise - returns Promise if no callback passed

principalDetails(service, hostname, [callback])

Param	Type	Description
service	string	The Kerberos service type for the server.
hostname	string	The hostname of the server.
[callback]	function

This function returns the service principal for the server given a service type and hostname.

Details are looked up via the /etc/keytab file.

Returns: Promise - returns Promise if no callback passed

initializeClient(service, [options], [callback])

Param	Type	Description
service	string	A string containing the service principal in the form 'type@fqdn' (e.g. 'imap@mail.apple.com').
[options]	object	Optional settings
[options.principal]	string	Optional string containing the client principal in the form 'user@realm' (e.g. 'jdoe@example.com').
[options.flags]	number	Optional integer used to set GSS flags. (e.g. GSS_C_DELEG_FLAG|GSS_C_MUTUAL_FLAG|GSS_C_SEQUENCE_FLAG will allow for forwarding credentials to the remote host)
[options.mechOID]	number	Optional GSS mech OID. Defaults to None (GSS_C_NO_OID). Other possible values are GSS_MECH_OID_KRB5, GSS_MECH_OID_SPNEGO.
[callback]	function

Initializes a context for client-side authentication with the given service principal.

Returns: Promise - returns Promise if no callback passed

initializeServer(service, [callback])

Param	Type	Description
service	string	A string containing the service principal in the form 'type@fqdn' (e.g. 'imap@mail.apple.com').
[callback]	function

Initializes a context for server-side authentication with the given service principal.

Returns: Promise - returns Promise if no callback passed