smt/README.md

title

title
Secrets Management Tool (SMT)

Build Date: {BUILDTIME}

Build Hash: {SHA1VER}

Written by Nathan Coad (nathan.coad@dell.com)

Overview

Provide REST API to store and retrieve secrets with associated username, device name and optionally device class. Secrets are stored in sqlite database once encrypted using an AES256 block cipher wrapped in Galois Counter Mode with the standard nonce length.

All secret operations (Create, Read, Update or Delete) or user maangement operations require successful authentication. A JWT token is returned upon login, which must be provided for any other operation.

Users must be a member of a single group. Groups can have access to multiple safes. Groups can have read-only or read-write access to safes. Only users with an admin role can perform user-related operations such as creating users or groups, or creating/deleting safes. Users and groups can be either locally defined or sourced from LDAP lookups.

Installation

Only tested on x64 Linux, but code should compile on other platforms.

1. Copy binary to chosen location, eg /srv/smt/smt
2. Create .env file in same directory as binary, populate as per Configuration section below
3. Create systemd service definition
4. Start service

Configuration

Environment Variable Name	Description	Example	Default
LOG_FILE	Specify the name/path of file to write log messages to	/var/log/smt.log	./smt.log
BIND_IP	Specify the local IP address to bind to.	127.0.0.1	Primary IPv4 address
BIND_PORT	Specify the TCP/IP port to bind to.	443	8443
TLS_KEY_FILE	Specify the filename of the TLS certificate private key (must be unencrypted) in PEM format	key.pem	privkey.pem
TLS_CERT_FILE	Specify the filename of the TLS certificate file in PEM format	cert.pem	cert.pem
TOKEN_HOUR_LIFESPAN	Number of hours that the JWT token returned at login is valid	12	No default specified, must define this value
API_SECRET	Secret to use when generating JWT token	3c55990bd479322e2053db3a8	No default specified, must define this value
INITIAL_PASSWORD	Password to set for builtin Administrator account created when first started, can remove this value after first start. Can specify in plaintext or bcrypt hash	$2a$10$s39a82wrRAdOJVZEkkrSReVnXprz5mxU30ZBO.dHPYTncQCsUD9ce	password
SECRETS_KEY	Key to use for AES256 GCM encryption. Must be exactly 32 bytes	AES256Key-32Characters1234567890	No default specified, must define this value or use /api/unlock at runtime

If the TLS certificate and key files cannot be located in the specified location, a self signed certificate will be generated with a 1 year validity period.

Example for generating API_SECRET and SECRETS_KEY is the following command on linux: head /dev/urandom | tr -dc A-Za-z0-9 | head -c32

LDAP specific configuration

Several optional environment variables are available to configure LDAP integration if required. If these parameters are not specifed, LDAP integration will not be used.

If the LDAP_BIND_ADDRESS is specified, SMT will attempt to perform an LDAP search for the provided username if no matches to the locally configured users are found in the database. This search will utilise the provided credentials to perform the LDAP bind.

This lookup will utilise the sAMAccountName property of the user object in Active Directory. No other LDAP providers have been tested.

Upon successfully verifying the LDAP credentials, SMT will verify if any of the group memberships matches a role defined in the SMT database. If no match is found, the authentication will not succeed.

Environment Variable Name	Description	Example	Default
LDAP_BIND_ADDRESS	Specify the LDAP Bind address. Only LDAPS on port 636 is supported. Do not specify port 636 in the bind address	dc.example.com	No default specified
LDAP_BASE_DN	Specify the base DN to use when binding to AD	"CN=Users,DC=example,DC=com"	No default specified
LDAP_TRUST_CERT_FILE	Specify filepath to PEM format public certificate of Certificate Authority signing LDAPS communications	caroot.pem	No default specified, must define this value
LDAP_INSECURE_VALIDATION	Specify whether to skip certificate validation when connecting to LDAPS. Do not enable this in production	true	false

Systemd script

Create/update the systemd service definition at /etc/systemd/system/smt.service and then run systemctl daemon-reload

[Unit]
Description=Secrets Management Tool
After=network.target
#StartLimitIntervalSec=0

[Service]
Type=simple
Restart=always
RestartSec=1
User=root
ExecStart=/srv/smt/smt

[Install]
WantedBy=multi-user.target

API Usage

Login

POST /api/login

Body

{
    "username": "example_username", 
    "password": "example_password"
}

This API call will return a JWT token that must be present for any other API calls to succeed. The validity duration of this token is based on the configured TOKEN_HOUR_LIFESPAN value. JWT token is returned as value of access_token, and must be supplied via a HTTP header in the form "Authorization: Bearer <JWT_TOKEN>" for all subsequent API calls.

Unlock

POST /api/admin/unlock

Body

{
    "secretKey": "Example32ByteSecretKey0123456789"
}

If the SECRETS_KEY environment variable is not defined, this API call to unlock stored secrets must be performed after initial startup of SMT. Storing/retrieval of secrets will not succeed until this API call has been made.

This API call can only be made once after the service has started. Subsequent calls will receive an error until the service is restarted.

User Operations

Register User

POST /api/admin/user/add

Create a new user record by specifying groupId

Body

{
    "userName": "Test User", 
    "password": "Example Password",
    "groupId": "1",
}

Create a new user record by specifying groupName

Body

{
    "userName": "Test User", 
    "password": "Example Password",
    "groupName": "Users",
}

Registering a user requires specifying the group to which the user will belong. There are 2 built-in groups, with groupName of 'Administrators' or 'Users' and corresponding groupId of 1 and 2 respectively. Available groups can be retrieved via the /api/admin/groups/list

This operation can only be performed by a user that is a member of a group with the admin flag enabled, or a user who has the admin flag enabled individually on their database record.

Remove User

POST /api/admin/user/delete

Body

{
    "userName": "example_username"
}

This operation can only be performed by a user that is admin enabled. Removes user account corresponding to specified userName.

List Users

GET /api/admin/users

This operation can only be performed by a user that is admin enabled. Lists currently defined users.

Permission Operations

Permissions can be assigned either via a group or directly to a user Id. Permissions map the user to the safe(s) they are allowed to access. By default a permission grants read-write access to a safe, although that can be set to read-only if required.

List Permissions

GET /api/admin/permissions

This operation can only be performed by a user that is admin enabled. Lists currently defined permissions.

Create Permission

POST /api/admin/permission/add

Create a new read-only permission directly to a user

Body

{
    "Description": "Readonly access to default safe",
    "safeId": 1,
    "userId": 2,
    "readOnly": true
}

Creates a new permission mapping user/group to safe. Currently the create permission operation requires knowing the correct user Id or group Id, as well as the safe Id onto which permissions will be granted. This operation can only be performed by a user that is admin enabled.

Delete Permission

POST /api/admin/permission/delete

Delete permission by specifying description

Body

{
    "Description":"Readonly access to default safe"

}

Delete permission by specifying permission id

Body

{
    "permissionId":2

}

Deletes a permission mapping either a user or a group to a safe. Either the permission description or permission Id can be specified. This operation can only be performed by a user that is admin enabled.

Deleting a permission should be performed prior to deleting any groups specified in that permission.

Group Operations

List Groups

GET /api/admin/groups

This operation can only be performed by a user with that is admin enabled. Lists currently defined groups.

Create Group

POST /api/admin/group/add

Create a new group corresponding with an LDAP group

Body

{
    "groupName":"ldap access for smt_users",
    "ldapGroup":true,
    "LdapDn":"CN=smt_users,OU=Groups,DC=example,DC=com"
}

Create a new local admin group

Body

{
    "groupName":"admin group",
    "Admin":true,

}

Creates a new group, which can be entirely local or mapped to an LDAP security group if LDAP integration is enabled. This operation can only be performed by a user that is admin enabled, or that is a member of a group that is admin enabled.

Ldap group must be specified via the full distinguishedName. The simplest way to get this information is to run the command dsquery group -name <known group name> from a windows machine.

Delete Group

POST /api/admin/group/delete

Delete group by specifying group name

Body

{
    "groupName":"admin group"

}

Delete group by specifying group id

Body

{
    "groupId":2

}

Deletes an existing group. Either group name or group Id can be specified. If both are specified, group Id takes precedence. This operation can only be performed by a user that is admin enabled, or that is a member of a group that is admin enabled.

Deleting a group will also impact all permissions based on that group. For that reason, permissions should be removed before a group is deleted.

Secrets Operations

Store

POST /api/secret/store

Store secret if user only has access to a single safe

Body

{
    "deviceName": "device.example.com",
    "deviceCategory": "appliance",
    "userName": "example-user",
    "secretValue": "example-password"
}

Store secret if user only has access to multiple safes

Body

{
    "safeId": 1,
    "deviceName": "device.example.com",
    "deviceCategory": "appliance",
    "userName": "example-user",
    "secretValue": "example-password"
}

Must be logged in to execute this command. Permission assigned to logged-in user cannot be a ReadOnly role. Either deviceName or deviceCategory can be blank but not both.

If a secret exists with a matching deviceName and deviceCategory in a safe that the user has access to, then an error will be generated.

If the current user has access to multiple safes, then the destination safeId will also need to be specified.

Retrieve

POST /api/secret/retrieve

Data

{
    "deviceName": "",
    "deviceCategory": "",
    "userName": ""
}

Must be logged in to execute this command. Only secrets registered with the current user's RoleId can be retrieved.

Either deviceName or deviceCategory can be specified (or both). Wildcards are supported for both deviceName and deviceCategory fields. userName can also be specified in conjunction with deviceName or deviceCategory.

1. The percent sign % wildcard matches any sequence of zero or more characters.
2. The underscore _ wildcard matches any single character.

Search by device name

GET /api/secret/retrieve/name/<searchname>

Search for a secret specified by deviceName using a GET request. Must be logged in to execute this command. Only secrets registered with the current user's RoleId can be retrieved.

Search by device category

GET /api/secret/retrieve/category/<searchname>

Search for a secret specified by deviceCategory using a GET request. Must be logged in to execute this command. Only secrets registered with the current user's RoleId can be retrieved.

Update

POST /api/secret/update

Update secret value for existing secret record

Body

{
    "deviceName": "device.example.com",
    "deviceCategory": "appliance",
    "userName": "example-user",
    "secretValue": "new-password"
}

Move secret into different safe

Body

{
    "safeId": 2,
    "deviceName": "device.example.com",
    "deviceCategory": "appliance",
    "userName": "example-user",
    "secretValue": "example-password"
}

The values specified in deviceName and deviceCategory must match exactly one existing secret record for the safes available to the currently logged in user. Wildcards are supported for deviceName and deviceCategory.

If a user has read-write access to multiple safes, then specifying a different safeId to the one currently holding the secret will allow the secret to be moved into the other safe.

List

GET /api/secret/list

Will generate a list of device names and categories but not secret data.

Database Schema