Configuration

The configuration of the @PLUGIN@ plugin is done in the gerrit.config file. auth.type must be set to OAUTH:

[auth]
  type = OAUTH

For a per-provider overview of the security-relevant features (Git-over-HTTP, defense-in-depth checks, user-info mapper, PKCE), see the provider capability matrix.

Providers are configured under @PLUGIN@ section, appended with provider suffix: e.g. -google-oauth or -github-oauth:

  [plugin "@PLUGIN@-google-oauth"]
    client-id = "<client-id>"
    client-secret = "<client-secret>"
    link-to-existing-openid-accounts = true
    enable-git-over-http = false # Optional, when true git over HTTPS can authenticate with a Google access token issued for a trusted client (client-id, or a trusted-audience entry). Not compatible with domain. See config-google.md.
    # enable-pkce = true # Optional, when true the browser authorization-code flow uses PKCE.
    # enable-token-refresh = false # Optional, when true request a Google refresh_token (access_type=offline) so an expired browser access token is renewed automatically. See "Token refresh" below.
    # force-consent = false # Optional, with enable-token-refresh: send prompt=consent to force Google to re-issue a refresh_token (Google issues one only on first consent). User-visible on every login; leave off in production.
    # trusted-audience = "<cli-client-id>" # Optional, repeatable: additional Google client-ids (e.g. a Desktop client for git credential helpers) whose tokens the git path accepts. See config-google.md.

  [plugin "@PLUGIN@-github-oauth"]
    root-url = "<github url>" # https://github.com/ or https://git.company.com/
    client-id = "<client-id>"
    client-secret = "<client-secret>"
    enable-git-over-http = false # Optional, when true git over HTTPS can authenticate with a GitHub access token issued for this OAuth app. See config-github.md.
    # enable-pkce = true # Optional, when true the browser authorization-code flow uses PKCE.

  [plugin "@PLUGIN@-cas-oauth"]
    root-url = "<cas url>"
    client-id = "<client-id>"
    client-secret = "<client-secret>"
    use-json-extractor = false
    enable-pkce = true # Optional, when true the browser authorization-code flow uses PKCE (RFC 7636).

  [plugin "@PLUGIN@-gitlab-oauth"]
    root-url = "<gitlab url>"
    client-id = "<client-id>"
    client-secret = "<client-secret>"
    # enable-pkce = true # Optional, when true the browser authorization-code flow uses PKCE.
    # enable-git-over-http = false # Optional, when true git over HTTPS can authenticate with a GitLab access token issued for a trusted app (client-id, or a trusted-audience entry). See config-gitlab.md.
    # required-scope = read_user # Optional, repeatable; scope(s) the Git-over-HTTP token must carry (default read_user). See config-gitlab.md.
    # trusted-audience = "<helper-client-id>" # Optional, repeatable: additional GitLab application ids (e.g. a git credential helper's client) whose tokens the git path accepts. See config-gitlab.md.

  [plugin "@PLUGIN@-dex-oauth"]
    domain = "<domain for username manipulation (optional)>"
    service-name = "<custom service name (optional)>"
    root-url = "<dex url>"
    client-id = "<client-id>"
    client-secret = "<client-secret>"
    # enable-pkce = true # Optional, when true the browser authorization-code flow uses PKCE.

  [plugin "@PLUGIN@-airvantage-oauth"]
    client-id = "<client-id>"
    client-secret = "<client-secret>"
    # enable-pkce = true # Optional, when true the browser authorization-code flow uses PKCE.

  [plugin "@PLUGIN@-phabricator-oauth"]
    client-id = "<client-id>"
    client-secret = "<client-secret>"
    root-url = "<phabricator url>"
    # enable-pkce = true # Optional, when true the browser authorization-code flow uses PKCE.

  [plugin "@PLUGIN@-bitbucket-oauth"]
    client-id = "<client-id>"
    client-secret = "<client-secret>"
    # enable-pkce = true # Optional, when true the browser authorization-code flow uses PKCE.

  [plugin "@PLUGIN@-facebook-oauth"]
    client-id = "<client-id>"
    client-secret = "<client-secret>"
    # enable-pkce = true # Optional, when true the browser authorization-code flow uses PKCE.

  [plugin "@PLUGIN@-azure-oauth"]
    client-id = "<client-id>"
    client-secret = "<client-secret>"
    tenant = "<tenant (optional defaults to organizations if not set)>"
    link-to-existing-office365-accounts = true # Optional, if set will try to link old account with the @PLUGIN@-office365-oauth naming
    # enable-pkce = true # Optional, when true the browser authorization-code flow uses PKCE.
    # enable-git-over-http = false # Optional, when true Git-over-HTTPS can authenticate with an Azure access token that this Gerrit's Azure app minted; the plugin introspects it at Microsoft Graph /me. See the Azure section below.

  [plugin "@PLUGIN@-keycloak-oauth"]
    # Prior to Keycloak V17 /auth path must be added to the root-url, see this migration instruction:
    # https://www.keycloak.org/migration/migrating-to-quarkus
    root-url = "<root url>" # for example, https://signon.example.com, or https://signon.example.com/auth
    realm = "<realm>"
    client-id = "<client-id>"
    client-secret = "<client-secret>"
    use-preferred-username = true # Optional, if false will not send preferred_username from Keycloak to leave username unset
    enable-pkce = true # Optional, when true the browser flow uses PKCE (RFC 7636); required for public clients
    enable-git-over-http = false # Optional, when true git clone/fetch/push over HTTPS can authenticate with a Keycloak access_token. See config-keycloak.md.
    # link-to-existing-gerrit-accounts = false # Optional; when true the browser flow sets a gerrit:<preferred_username> claimed identity to link a first login to an existing account.

  # Auth0, Authentik, Cognito, LemonLDAP::NG and Tuleap no longer have dedicated
  # sections. They are generic OpenID Connect providers and have been removed in
  # favour of the @PLUGIN@-discovery-oauth section below; see config-discovery.md
  # for a per-provider migration recipe that preserves existing external ids.

  [plugin "@PLUGIN@-sapias-oauth"]
    root-url = "<root url>" # for example, https://sapias.example.com
    client-id = "<client-id>"
    client-secret = "<client-secret>"
    link-to-existing-gerrit-accounts = false
    enable-pkce = true
    enable-git-over-http = true # SAP IAS is grandfathered on; set false to disable Git-over-HTTP.
    enable-resource-owner-password-flow = false

  [plugin "@PLUGIN@-discovery-oauth"]
    root-url = "<root url>" # The part before /.well-known. for example, https://kanidm.example.com/oauth2/openid/gerrit
    client-id = "<client-id>"
    client-secret = "<client-secret>"
    enable-pkce = true
    enable-git-over-http = false # Optional, when true git over HTTPS can authenticate with an IdP-signed JWT whose aud is this client-id. Requires the discovery document to expose jwks_uri. See config-discovery.md.
    # external-id-scheme = discovery-oauth # Optional; the external-id scheme (default discovery-oauth). Set it to a removed wrapper's scheme (e.g. auth0-oauth) to migrate that provider to Discovery without unlinking accounts. See config-discovery.md.
    # link-to-existing-gerrit-accounts = false # Optional; when true the browser flow sets a gerrit:<username> claimed identity to link a first login to an existing account (matches Authentik/Cognito). See config-discovery.md.
    # client-auth-method = basic # Optional; token-endpoint client auth: basic (HTTP Basic, default) or request-body (client_id/client_secret in the POST body, e.g. a default LemonLDAP::NG). See config-discovery.md.

When only one of the sections above is configured, OAuth SSO is used directly and the login form with provider selection isn’t shown. When all sections are omitted, Gerrit will not start.

Google OAuth provider seamlessly supports linking of OAuth identity to existing OpenID accounts. This feature is deactivated by default. To activate it, add

plugin.gerrit-oauth-provider-google-oauth.link-to-existing-openid-accounts = true

to Google OAuth configuration section.

It is possible to restrict sign-in to accounts of one or more (hosted) domains for Google OAuth. Multiple domain options can be added:

plugin.gerrit-oauth-provider-google-oauth.domain = "mycollege.edu"
plugin.gerrit-oauth-provider-google-oauth.domain = "myschool.net"

See the spec for more information. To protect against client-side request modification, the returned ID token is checked to contain a matching hd claim (which is proof the account does belong to the hosted domain). If the hd claim wasn‘t included in ID token or didn’t match the provided domain configuration option the authentication is rejected. Note: because of a current limitation of the OAuth extension point in Gerrit, the user would only see an “Unauthorized” message.

By default the Google OAuth provider will not set a username (used for ssh) and the user can choose one from the web ui (needed before using ssh). It is possible to automatically use the user part from the google apps email. This is deactivated by default. To activate it, add:

plugin.gerrit-oauth-provider-google-oauth.use-email-as-username = true

Note: the usernames are unique in gerrit. If a username already exists this will be ignored and the user will have to choose a different one from the web ui.

CAS OAuth

For CAS OAuth setting

plugin.gerrit-oauth-provider-cas-oauth.root-url = "https://example.com/cas"

is required, since CAS is a self-hosted application.

Note that the CAS OAuth plugin only supports CAS V5 and higher. Both plain text and JSON responses are supported (see configuration).

The plugin expects CAS to make several attributes available to it:

NameDescriptionRequired
idExternal IDyes
loginLogin nameno
emailEmail addressno
nameDisplay nameno

CoreOS Dex OAuth

For Dex OAuth setting

plugin.gerrit-oauth-provider-dex-oauth.root-url = "https://example.com"

is required, since Dex is a self-hosted application.

The Dex id_token is verified against Dex's JWKS: its signature, aud == client-id, exp, and issuer are checked before its claims are trusted. Dex is mounted under /dex (its endpoints are <root-url>/dex/auth and <root-url>/dex/token), so the issuer is <root-url>/dex and the JWKS is <root-url>/dex/keys; Gerrit must be able to reach the latter. If client-id is unset the check is disabled and the token is decoded unsigned (prior behavior).

Obtaining provider authorizations

Google

To obtain client-id and client-secret for Google OAuth, go to Google Developers Console:

  • Create a project

    Create a project

  • Go inside the created project

  • In “APIs & auth”/“Credentials” select “Create new Client ID” and create Client ID for a Web application

    Create Client ID for a Web application

  • Enter additional information about the project, which will be presented to user during the authentication process

    Enter additional information

  • Specify authorized redirect URL: <canonical-web-uri-of-gerrit>/oauth

    Specify authorized redirect URI

After the final step, the page will show generated client id and secret.

Generated id and secret

Token refresh

enable-token-refresh = true requests a Google refresh token (via access_type=offline) so an expired access token can be renewed instead of forcing a re-login. An expired token is renewed on read: browser/REST reads (GET /accounts/{id}/oauthtoken) and the core oauth-token SSH command both refresh it via OAuthTokenRefresher; it needs only enable-token-refresh on the issuing provider, not enable-git-over-http. Renewal happens at retrieval time, not during a Git-over-HTTP request, which validates the presented token as-is. force-consent = true additionally sends prompt=consent to make Google re-issue a refresh token (Google returns one only on the first consent); it is user-visible on every login, so leave it off in production.

Security -- stored refresh tokens. Enabling token refresh persists long-lived refresh tokens in Gerrit's oauth_tokens cache (<review_site>/cache/oauth_tokens-*.mv.db). By default this cache is stored in cleartext (as access tokens have been since the cache was introduced). To encrypt the stored token/secret/raw fields, generate a base64-encoded AES key of 16, 24 or 32 raw bytes (128/192/256-bit -- the number is the byte count, not the base64 string length):

  openssl rand -base64 32              # AES-256 (recommended)
  # or, without openssl:
  head -c 32 /dev/urandom | base64

and set the output as the core key (see config-gerrit.html#auth.tokenEncryptionKey):

  [auth]
    tokenEncryptionKey = <paste the base64 output here>

Gerrit core then binds an AES-GCM OAuthTokenEncrypter, so tokens are encrypted before they are written to the cache and decrypted on read; tokens cached before the key was set keep working (read as cleartext until rewritten). Keep the key secret and back it up -- losing it makes the cached tokens unreadable. When auth.type = OAUTH and no key is set, core logs a warning at startup that tokens are persisted in cleartext; restrict filesystem access to review_site/cache, or set enable-token-refresh = false, if that is unacceptable.

GitHub

To obtain client-id and client-secret for GitHub OAuth, go to Applications settings in your GitHub account:

  • Select “Register new application” and enter information about the application.

    Note that it is important that authorization callback URL points to <canonical-web-uri-of-gerrit>/oauth.

    Register new application on GitHub

After application is registered, the page will show generated client id and secret.

Generated client id and secret

CAS

The client-id and client-secret for CAS OAuth are part of the CAS service definition and need to be set manually.

See the CAS documentation for an example.

GitLab

To obtain client-id and client-secret for GitLab OAuth, go to Applications settings in your GitLab profile:

  • Select “Save application” and enter information about the application.

    Note that it is important that Redirect URI points to <canonical-web-uri-of-gerrit>/oauth.

    Save new application on GitLab

After application is saved, the page will show generated client id and secret.

Generated client id and secret

CoreOS Dex

The client-id and client-secret for Dex OAuth are part of the Dex setup and need to be set manually.

See Using Dex for an example.

AirVantage

The client-id and client-secret for AirVantage OAuth can be obtained by registering a Client application. See Getting Started.

Phabricator

The client-id and client-secret for Phabricator can be obtained by registering a Client application. See Using the Phabricator OAuth Server.

Azure (previously named Office365)

Azure was previously named Office365. Both plugin.gerrit-oauth-provider-azure-oauth and plugin.gerrit-oauth-provider-office365-oauth are supported by the Azure OAuth. When running java gerrit.war init it will check the existing config to see if it finds the old naming and use that during the init run, if it does not find the office365-oauth it will use the new azure-oauth naming.

The client-id and client-secret for Azure can be obtained by registering a new application, see OAuth 2.0 and OpenID Connect protocols on Microsoft identity platform.

Token refresh

Set enable-token-refresh = true (default false) to make Azure refresh-capable; Azure already requests the offline_access scope, so a refresh_token is available with no extra configuration. An expired token is renewed on read: browser/REST reads (GET /accounts/{id}/oauthtoken) refresh it via OAuthTokenRefresher before returning it, and the core oauth-token SSH command refreshes on demand. Both need only enable-token-refresh on the issuing provider, not enable-git-over-http. Neither refreshes during a Git-over-HTTP request, which introspects the presented token at Microsoft Graph /me as before.

Username

By default, Azure OAuth will not set a username (used for ssh) and the user can choose one from the web ui.

plugin.gerrit-oauth-provider-azure-oauth.use-email-as-username = true

Tenant

The Azure OAuth is default set to use the tenant organizations but a specific tenant can be used by the option tenant. If a tenant other than common, organizations or consumers is used then the tokens will be validated that they are originating from the same tenant that is configured in the Gerrit OAuth plugin. See Microsoft identity platform and OpenID Connect protocol

plugin.gerrit-oauth-provider-azure-oauth.tenant = <tenant to use>

Regardless of tenant all tokens will be checked that they contain the client_id set in the Azure OAuth.

For a fixed tenant (anything other than common/organizations/consumers), the browser login additionally validates the id_token cryptographically against that tenant's JWKS (signature, aud == client-id, exp, and the pinned issuer https://login.microsoftonline.com/<tenant>/v2.0), and binds the verified tid to the configured tenant. The multi-tenant aliases keep the previous behavior (unverified aud/tid parse), because their issuer varies per user and needs tenant-independent key-issuer handling; JWKS validation on the browser flow therefore requires a fixed tenant.

Configure a fixed tenant by its tenant GUID, not a verified domain: Microsoft's issuer and the tid claim are both GUIDs, so a domain-form tenant (contoso.onmicrosoft.com) would mismatch the pinned issuer and the tid check. (The pre-existing tid == tenant check was already GUID-only.) A fixed tenant configured without a non-blank client-id fails fast at startup.

Git-over-HTTP

Set enable-git-over-http = true to let a Git client authenticate over HTTPS with an Azure access token in the password field. Because Microsoft treats Graph access tokens as opaque to clients (only Microsoft Graph can validate them), the plugin validates the token by introspection, not local signature checking:

  • It calls Microsoft Graph GET /v1.0/me with the token. Success proves the token is authentic and unexpired and yields the same azure-oauth:<id> external id the browser flow uses (from /me.id).
  • It reads the token's client-app claims (appid/azp) and requires at least one to be present and every present one to equal client-id. The token must therefore be minted by the Azure app registration this Gerrit trusts (same client-id). A token from a separate helper/CI app registration is rejected; supporting one would need an Azure trusted-audience equivalent, which is not yet implemented. An opaque or unparseable token is rejected, because the client-app binding cannot be verified.
  • For a fixed tenant the token's tid must equal the configured tenant.
  • Successful validations are cached only when the token carries a parseable exp (Graph /me returns no expiry); otherwise every request is re-validated at Graph.

As with the other providers, at most one provider may have enable-git-over-http = true at a time.

Migrating from Office365 naming

If this were previously installed with the office365-oauth you can migrate to azure-oauth by setting the flag.

plugin.gerrit-oauth-provider-azure-oauth.link-to-existing-office365-accounts = true

This will try to link the old office365-oauth external id to the new azure-oauth external id automatically. Another option is to migrate these manually offline, see External IDs for more information.

Keycloak

When setting up a client in Keycloak for Gerrit, enter a value for the Client ID and ensure you choose the openid-connect protocol and select the confidential access type. Once you click save, a Credentials tab will appear where you will find the Secret.

The root URL will be the protocol and hostname of your Keycloak instance (for example, https://signon.example.com).

You can optionally set use-preferred-username = false if you would prefer to not have the preferred_username token be automatically set as the users username, and instead let users choose their own usernames.

You can optionally set link-to-existing-gerrit-accounts = true if you want the provider to link an account based on the username instead of trying to create a new account, see Linking to existing (LDAP) Gerrit accounts below.

Linking to existing (LDAP) Gerrit accounts

The SAP IAS, Discovery and Keycloak providers support link-to-existing-gerrit-accounts = true, which links a login to an existing Gerrit account by username instead of always creating a new account.

If you have used LDAP before and have accounts with external ids like gerrit:firstname.lastname, and a user whose IdP username is firstname.lastname logs in, the OAuth account is linked to that Gerrit account.

Once every user has logged in once via OAuth it is recommended to remove the option again.

SAP IAS

When setting up an Application for Gerrit in SAP Cloud Identity Service follow “Configuring OpenID Connect”. For end user authentication follow “Using Authorization Code Flow”. Then configure the URL of your IAS tenant and client-id and client-secret in gerrit.config.

You can optionally set link-to-existing-gerrit-accounts = true if you want the provider to link an account based on the username instead of trying to create a new account, see Linking to existing (LDAP) Gerrit accounts above.

You can optionally set enable-pkce = true if you want to use PKCE as part of the authorization workflow during login.

If login via password for git over HTTP or REST API should still be possible, the Resource Owner Password Flow can optionally be enabled. This OAuth flow lets the user send the password and Gerrit will use that password to authenticate the user against the OAuth server. Note, that this flow is not considered to be secure. To enable this flow set enable-resource-owner-password-flow = true.

Migrating a removed wrapper (Auth0, Authentik, Cognito, Tuleap, LemonLDAP) to Discovery

The dedicated Auth0, Authentik, Cognito, Tuleap and LemonLDAP::NG providers have been removed. They are generic OpenID Connect IdPs, so configure them through the Discovery provider (the @PLUGIN@-discovery-oauth section above). To keep existing accounts linked, set external-id-scheme to the wrapper's scheme (auth0-oauth, authentik-oauth, cognito-oauth, tuleap-oauth, llng-oauth).

Each has a worked recipe -- the correct root-url (Authentik‘s per-app issuer, Cognito’s user-pool issuer, ...), the scheme to preserve, and any link-to-existing-gerrit-accounts / client-auth-method twist -- in config-discovery.md. That page also documents the one-Discovery-instance limitation: a site that ran more than one of these wrappers at once can migrate only one of them to Discovery.

OpenID Connect Discovery 1.0 URL

This supports the OpenID Connect Discovery 1.0 spec, which is supported by many providers.

The discovery URL looks like below:

https://idm.example.com/oauth2/openid/:client_id:/.well-known/openid-configuration

Set the root-url to the part before /.well-known of the discovery URL of your OAuth server, and client-id and client-secret in gerrit.config.

You can optionally set enable-pkce = true if you want to use PKCE as part of the authorization workflow during login.

Tested providers:

  • Authelia
  • Kanidm