Configure custom authorization servers for External OAuth¶
This topic describes how to create an External OAuth security integration in Snowflake, so clients can access Snowflake data by authenticating with a custom authorization server.
If your authorization server is a supported identity provider (IdP) rather than a custom one, refer to the topic focused on configuring that specific IdP.
External OAuth token payload requirements¶
The access token that custom authentication servers send to Snowflake must contain the following payload information. For more information about the Claims column, see JWT Claims (https://tools.ietf.org/html/rfc7519#section-4).
Claims |
Description |
---|---|
scp |
Scopes. A list of scopes in the access token. |
scope |
Scopes. A comma-separated string of scopes in the access token. Snowflake supports specifying any single character for the delimiter, such as a space (i.e. Contact Snowflake Support to enable this property in your Snowflake account. |
aud |
Audience. Identifies the recipients that the access token is intended for as a string URI. |
exp |
Expiration time. Identifies the expiration time on or after which the access token must not be accepted for processing. |
iss |
Issuer. Identifies the principal that issued the access token as a string URI. |
iat |
Issued at. Required. Identifies the time at which the JWT was issued. |
Note
Snowflake supports the nbf
(not before) claim, which identifies the time before which the access token must not be
accepted for processing.
If your custom authorization server supports the nbf
(not before) claim, you can optionally include the nbf
claim in the
access token.
To verify your token contains the required information, you can test the token on this JSON Web Tokens (https://jwt.ms) site.
As a representative example, the PAYLOAD: DATA interface displays the token payload as follows.
{
"aud": "<audience_url>",
"iat": 1576705500,
"exp": 1576709100,
"iss": "<issuer_url>",
"scp": [
"session:role:analyst"
]
}
Configuration procedure¶
The following steps assume that your custom authorization server and environment can be configured to obtain the necessary values to create the Snowflake Security Integration.
Important
The steps in this topic are a representative example on how to configure custom authorization servers.
You can configure your environment to any desired state and use any desired OAuth flow provided that you can obtain the necessary information for the External OAuth security integration.
Note that the following steps serve as a guide to obtain the necessary information to create the External OAuth security integration in Snowflake.
Consult your internal security policies before configuring a custom authorization server to ensure your organization meets all regulations and compliance requirements.
Obtain key environment values to use External OAuth¶
When you configure your IdP and authorization server, you must collect the following values to define an External OAuth security integration:
- Issuer URL:
Include this URL with the
external_oauth_issuer
parameter.- RSA Public Key:
Include this value with the
external_oauth_rsa_public_key
parameter.- Audience URLs:
If more than one Audience URL is necessary, separate each URL with a comma in the
external_oauth_audience_list
parameter.- Scope attribute:
You can set this value to
scp
orscope
. By default, this value isscp
.You can set the value of the
external_oauth_scope_mapping_attribute
parameter to this value.If you do not use the default value,
scp
, then set value of theexternal_oauth_scope_mapping_attribute
parameter toscope
.For more information, refer to External OAuth token payload requirements.
- User Attribute:
This attribute refers to attribute to identify users in your IdP. Include this attribute value in the
external_oauth_user_mapping_claim
parameter.- Snowflake User Attribute:
The attribute in Snowflake to identify users. Include this value in the
external_oauth_snowflake_user_mapping_attribute
parameter.
Create an External OAuth security integration in Snowflake¶
This step creates an External OAuth security integration in Snowflake. The External OAuth security integration ensures that Snowflake can communicate securely with and validate access tokens from your custom authorization server, and provide users access to Snowflake data based on their user role associated with the access token. For more information, see CREATE SECURITY INTEGRATION.
Important
Only account administrators or a role with the global CREATE INTEGRATION privilege can execute this SQL command.
The External OAuth security integration parameter values are case-sensitive, and the values you put into the External OAuth security integration must match the values in your environment. If the case of a value does not match, the access token will not be validated, resulting in a failed authentication attempt.
Create an External OAuth security integration in Snowflake
create security integration external_oauth_custom type = external_oauth enabled = true external_oauth_type = custom external_oauth_issuer = '<authorization_server_url>' external_oauth_rsa_public_key = '<public_key_value>' external_oauth_audience_list = ('<audience_url_1>', '<audience_url_2>') external_oauth_token_user_mapping_claim = 'upn' external_oauth_snowflake_user_mapping_attribute = 'login_name';Copy
Modifying Your External OAuth Security Integration¶
You can update your External OAuth security integration by executing an ALTER statement on the security integration.
For more information, see ALTER SECURITY INTEGRATION (External OAuth).
Using ANY role with External OAuth¶
In the configuration step to create a security integration in Snowflake, the OAuth access token includes the scope definition. Therefore, at runtime, using the External OAuth security integration allows neither the OAuth client nor the user to use an undefined role in the OAuth access token.
After validating the access token and creating a session, the ANY role can allow the OAuth client and user to decide its role. If necessary, the client or the user can switch to a role that is different that the role defined in the OAuth access token.
To configure ANY role, define the scope as SESSION:ROLE-ANY
and configure the security integration with the external_oauth_any_role_mode
parameter. This parameter can have three possible string values:
DISABLE
does not allow the OAuth client or user to switch roles (i.e.use role <role>;
). Default.ENABLE
allows the OAuth client or user to switch roles.ENABLE_FOR_PRIVILEGE
allows the OAuth client or user to switch roles only for a client or user with theUSE_ANY_ROLE
privilege. This privilege can be granted and revoked to one or more roles available to the user. For example:grant USE_ANY_ROLE on integration external_oauth_1 to role1;
Copyrevoke USE_ANY_ROLE on integration external_oauth_1 from role1;
Copy
Define the security integration as follows:
create security integration external_oauth_1
type = external_oauth
enabled = true
external_oauth_any_role_mode = 'ENABLE'
...
Using secondary roles with External OAuth¶
The desired scope for the primary role is passed in the external token: either the default role for the user (session:role-any
) or
a specific role that was granted to the user (session:role:<role_name>
).
By default, Snowflake does not activate the default secondary roles for a user (i.e. the DEFAULT_SECONDARY_ROLES) user in the session.
To activate the default secondary roles for a user in a session and allow executing the USE SECONDARY ROLES command while using External OAuth, complete the following steps:
Configure the security integration for the connection. Set the EXTERNAL_OAUTH_ANY_ROLE_MODE parameter value to either ENABLE or ENABLE_FOR_PRIVILEGE when you create the security integration (using CREATE SECURITY INTEGRATION) or later (using ALTER SECURITY INTEGRATION).
Configure the authorization server to pass the static value of
session:role-any
in the scope attribute of the token. For more information about the scope parameter, see External OAuth overview.
Using Client Redirect with External OAuth¶
Snowflake supports using Client Redirect with External OAuth, including using Client Redirect and External OAuth with supported Snowflake Clients.
For more information, see Redirecting client connections.
Using network policies with External OAuth¶
Currently, network policies cannot be added to your External OAuth security integration. However, you can still implement network policies that apply broadly to the entire Snowflake account.
If your use case requires a network policy that is specific to the OAuth security integration, use Snowflake OAuth. This approach allows the Snowflake OAuth network policy to be distinct from other network policies that may apply to the Snowflake account.
For more information, see Network policies.
Using replication with External OAuth¶
Supported regions for feature
This feature is not available in the People’s Republic of China.
Snowflake supports replication and failover/failback of the External OAuth security integration from a source account to a target account.
For details, see Replication of security integrations & network policies across multiple accounts.
Testing procedure¶
To test the configuration of a custom authorization server:
Verify that the test user exists in your IdP and has a password.
Verify that the test user exists in Snowflake with their
login_name
attribute value set to the<external_oauth_token_user_mapping_claim>
.Register an OAuth 2.0 client
Allow the OAuth 2.0 client to make a POST request to the custom token endpoint as follows:
Grant type set to Resource Owner
HTTP Basic Authorization header containing the clientID and secret
FORM data containing the username & password
Include scopes
The sample command requests the ANALYST
custom role and that assumes the session:role:analyst
has been defined in the custom
authorization server.
Here is an example for getting an access token using cURL.
curl -X POST -H "Content-Type: application/x-www-form-urlencoded;charset=UTF-8" \
--user <OAUTH_CLIENT_ID>:<OAUTH_CLIENT_SECRET> \
--data-urlencode "username=<IdP_USER_USERNAME>" \
--data-urlencode "password=<IdP_USER_PASSWORD>" \
--data-urlencode "grant_type=password" \
--data-urlencode "scope=session:role:analyst" \
<IdP_TOKEN_ENDPOINT>
Connecting to Snowflake with External OAuth¶
After configuring your security integration and obtaining your access token, you can connect to Snowflake using one of the following:
Go Driver (https://godoc.org/github.com/snowflakedb/gosnowflake#hdr-Connection_Parameters)
.NET Driver (https://github.com/snowflakedb/snowflake-connector-net/blob/master/README.md#create-a-connection)
Note the following:
It is necessary to set the
authenticator
parameter tooauth
and thetoken
parameter to theexternal_oauth_access_token
.When passing the
token
value as a URL query parameter, it is necessary to URL-encode thetoken
value.When passing the
token
value to a Properties object (e.g. JDBC Driver), no modifications are necessary.
For example, if using the Python Connector, set the connection string as shown below.
ctx = snowflake.connector.connect(
user="<username>",
host="<hostname>",
account="<account_identifier>",
authenticator="oauth",
token="<external_oauth_access_token>",
warehouse="test_warehouse",
database="test_db",
schema="test_schema"
)
You can now use External OAuth to connect to Snowflake securely.