Securing Configuration Files#

Introduction#

By default passwords (e.g. the default password for Redis or MySQL) are configured in plain text in the configuration files. However we provide a mechanism so that this sensitive information can be encrypted. The encryption happens on installation of Squirro. There are three different ways to encrypt values in configuration files:

Encryption Methods#

There are three modes of encrypting Squirro configuration files:

Encryption key in a Unix environment variable
Encryption key stored in a file
Custom command for encrypting and decrypting

Environment Variable#

If you set the value of the environment variable SQ_ENCRYPTION_KEY to a valid encryption key, all encrypted configuration values will be decrypted on load. If this environment variable is set prior to installation of Squirro already, then all sensitive configuration values will be encrypted with this key and stored in an encrypted fashion in the INI files. You recognise such a value as it starts with CK_FERNET::. On usage of the value it will be decrypted automatically.

Generating Key#

Run the following commands in Python to generate a valid encryption key:

from cryptography.fernet import Fernet
key = Fernet.generate_key()
print(key.decode())

Key Stored in a File#

This is very similar to the previous approach but the encryption key is stored in a file instead of an environment variable. For this to work you set SQ_ENCRYPTION_KEY_FILE environment variable to the (absolute) path of a file containing nothing but the encryption key.

For how to generate a valid encryption key, see the previous section.

Custom Encryption#

If you want to provide your own encryption and decryption algorithms instead, you can set the two environment variables SQ_ENCRYPT_COMMAND and SQ_DECRYPT_COMMAND. They are called with the configuration section and the configuration key as program arguments and the value to en/decrypt is sent on stdin. The en/decrypted value is returned on stdout with an exit status 0.

An example invocation of this script:

$ echo "my password"    | /usr/bin/my_decrypt mysql password

An example encryption and decryption script:

#!/bin/bash
cat /dev/stdin    | rev

This just reverts the order of the password - which is obviously not safe for production at all.

The prefix for encrypted values in this case is: CK_CMD.

Precedence#

If multiple of these environment variables are configured, the following shows the precedence:

SQ_ENCRYPTION_KEY
SQ_ENCRYPTION_KEY_FILE
SQ_ENCRYPT_COMMAND and SQ_DECRYPT_COMMAND

Encrypt#

To encrypt values, set the right environment variables before installing Squirro.

If you want to turn on encryption after the initial Squirro installation, run the following command:

python /opt/squirro/tools/secure-001-encrypt-config-files.py

The Squirro environment needs to be activated for this, as follows:

CentOS7 / RH7

source /opt/rh/rh-python36/enable;
source /opt/squirro/virtualenv3/bin/activate;

CentOS8 RH8

source /opt/squirro/virtualenv3/bin/activate;

Validate Encryption#

Only encoded passwords found in configuration files.

Validate Encryption

$ cd /etc/squirro

# should return nothing
$ grep -rn . -e $PLAIN_PASSWORD

# should return all encoded passwords
$ grep -rn . -e 'CK_FERNET'
./cluster.ini:14:password = CK_FERNET::gAAAAABhQz8...
./datasource.ini:15:redis_password = CK_FERNET::gAAAAABhQz8wb2pcLWhZmao6zt9UeR...

Starting Squirro#

To start Squirro after you have encrypted the configuration files, ensure that this environment variable are available for the daemons. You do this by adding them in to the following file: /etc/sysconfig/squirro.

The file contains commented out versions of these keys by default. Comment out the appropriate key and set the desired value.

# encrypt passwords using the following settings per
# https://go.squirro.com/securing-config
# SQ_ENCRYPTION_KEY=
# SQ_ENCRYPTION_KEY_FILE=
# SQ_DECRYPT_COMMAND=
# SQ_ENCRYPT_COMMAND=

Securing Configuration Files

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