feat: add sourcing secondary claims from access_token (#16517)

Niche edge case, assumes access_token is jwt. 

Some `access_token`s are JWT's with potential useful claims.
These claims would be nearly equivalent to `user_info` claims.
This is not apart of the oauth spec, so this feature should not be
loudly advertised. If using this feature, alternate solutions are preferred.

cli/server.go

@@ -172,6 +172,17 @@ func createOIDCConfig(ctx context.Context, logger slog.Logger, vals *codersdk.De
 		groupAllowList[group] = true
 	}
 
+	secondaryClaimsSrc := coderd.MergedClaimsSourceUserInfo
+	if !vals.OIDC.IgnoreUserInfo && vals.OIDC.UserInfoFromAccessToken {
+		return nil, xerrors.Errorf("to use 'oidc-access-token-claims', 'oidc-ignore-userinfo' must be set to 'false'")
+	}
+	if vals.OIDC.IgnoreUserInfo {
+		secondaryClaimsSrc = coderd.MergedClaimsSourceNone
+	}
+	if vals.OIDC.UserInfoFromAccessToken {
+		secondaryClaimsSrc = coderd.MergedClaimsSourceAccessToken
+	}
+
 	return &coderd.OIDCConfig{
 		OAuth2Config: useCfg,
 		Provider:     oidcProvider,
@@ -187,7 +198,7 @@ func createOIDCConfig(ctx context.Context, logger slog.Logger, vals *codersdk.De
 		NameField:           vals.OIDC.NameField.String(),
 		EmailField:          vals.OIDC.EmailField.String(),
 		AuthURLParams:       vals.OIDC.AuthURLParams.Value,
-		IgnoreUserInfo:      vals.OIDC.IgnoreUserInfo.Value(),
+		SecondaryClaims:     secondaryClaimsSrc,
 		SignInText:          vals.OIDC.SignInText.String(),
 		SignupsDisabledText: vals.OIDC.SignupsDisabledText.String(),
 		IconURL:             vals.OIDC.IconURL.String(),

cli/testdata/server-config.yaml.golden

@@ -329,6 +329,12 @@ oidc:
   # Ignore the userinfo endpoint and only use the ID token for user information.
   # (default: false, type: bool)
   ignoreUserInfo: false
+  # Source supplemental user claims from the 'access_token'. This assumes the token
+  # is a jwt signed by the same issuer as the id_token. Using this requires setting
+  # 'oidc-ignore-userinfo' to true. This setting is not compliant with the OIDC
+  # specification and is not recommended. Use at your own risk.
+  # (default: false, type: bool)
+  accessTokenClaims: false
   # This field must be set if using the organization sync feature. Set to the claim
   # to be used for organizations.
   # (default: <unset>, type: string)