SASL Authentication Library for Erlang/Elixir

This library provides two SASL implementations

• The sasl_auth module implements a simple wrapper for cyrus sasl library. It helps to implement SASL GSSAPI auth mechanism support in your Erlang application.
• The sasl_auth_scram module implements SASL SCRAM authentication functions.

Dependencies

Ubuntu

On Ubuntu the following packages should be installed to build and use sasl_auth: libkrb5, libkrb5-dev, libsasl2, libsasl2-dev, libsasl2-modules-gssapi-mit.

See the dockerfiles in scripts/setup_and_run_rebar3_ct_in_docker for information about which packages are needed for other Linux distributions.

Redhat based distributions

Redhat 7 based distribution or compatabile

The following packages are required on Redhat 7 based or compatible distributions : cyrus-sasl, cyrus-sasl-devel, cyrus-sasl-gssapi, krb5-devel, and krb5-libs.

Use either yum or dnf (depending on redhat base version) to install cyrus-sasl, cyrus-sasl-gssapi, and krb5-libs.

yum install cyrus-sasl cyrus-sasl-devel cyrus-sasl-gssapi krb5-devel krb5-libs

Redhat 8 based distributions or compatabile

The following packages are required on Redhat 8 based or compatible distributions : cyrus-sasl-libs, cyrus-sasl-devel, cyrus-sasl-gssapi, krb5-devel, and krb5-libs.

dnf install cyrus-sasl-libs cyrus-sasl-devel cyrus-sasl-gssapi krb5-devel krb5-libs

Mac OS

Install cyrus-sasl via homebrew, this includes the gssapi module, as well MIT krb5 as a dependency :

brew install cyrus-sasl

Build

$ rebar3 compile

Test

You can execute the tests with the following command (if you have Docker installed):

./scripts/setup_and_run_rebar3_ct_in_docker.sh

By default, the script above runs the test in a docker container that is created from a docker image that is described in the file scripts/setup_and_run_rebar3_ct_in_docker/Dockerfile.ubuntu22.04. You can change the dockerfile by specifying the environment variable SASL_AUTH_DOCKER_FILE. The following command will run the tests in a Centos7 docker image:

SASL_AUTH_DOCKER_FILE=scripts/setup_and_run_rebar3_ct_in_docker/Dockerfile.centos7 ./scripts/setup_and_run_rebar3_ct_in_docker.sh

You can execute the following command to run the tests in a docker container with Erlang/OTP and the NIF library compiled with address sanitizer (finds memory errors and leaks):

./scripts/setup_and_run_rebar3_ct_in_docker.sh asan

It is a little bit more complicated to run the tests without Docker and the exact steps may depend on the operating system you are using. The following steps outlines what needs to be done:

1. Install necessary packages

   • The dockerfile scripts/setup_and_run_rebar3_ct_in_docker/Dockerfile.ubuntu22.04 contains information about which packages need to be installed in Ubuntu.

2. Configure a Kerberos server and create a keytab for a user

   • This can be done by following the steps in scripts/setup_and_run_rebar3_ct_in_docker/setup_and_run.sh until the command echo RUN TESTS.

3. Export and set the following environment variables to appropriate values:

   export SASL_AUTH_TEST_HOST=example.com  # Host that Kerberos is running on
   export SASL_AUTH_TEST_PRINCIPAL=user  # A user name
   export SASL_AUTH_TEST_KEY_TAB=user.keytab  # Keytab for user
   

4. Run the tests:

   rebar3 ct

References

sasl_auth

• brod_gssapi A GSSAPI authentication backend for the Apache Kafka client library for Erlang/Elixir brod. See usage details in the README file for brod_gssapi.
• Opensource MQTT broker EMQX

sasl_auth_scram

• Opensource MQTT broker EMQX
• There is also a similar but independent client-side-only implementation for reference: kpro_scram.