oidc: make email verification configurable

Co-authored-by: Kristoffer Dalby <kristoffer@tailscale.com>

CHANGELOG.md

@@ -57,6 +57,9 @@ sequentially through each stable release, selecting the latest patch version ava
 
 - Smarter change notifications send partial map updates and node removals instead of full maps [#2961](https://github.com/juanfont/headscale/pull/2961)
   - Send lightweight endpoint and DERP region updates instead of full maps [#2856](https://github.com/juanfont/headscale/pull/2856)
+- Add `oidc.email_verified_required` config option to control email verification requirement [#2860](https://github.com/juanfont/headscale/pull/2860)
+  - When `true` (default), only verified emails can authenticate via OIDC with `allowed_domains` or `allowed_users`
+  - When `false`, unverified emails are allowed for OIDC authentication
 - Add NixOS module in repository for faster iteration [#2857](https://github.com/juanfont/headscale/pull/2857)
 - Add favicon to webpages [#2858](https://github.com/juanfont/headscale/pull/2858)
 - Redesign OIDC callback and registration web templates [#2832](https://github.com/juanfont/headscale/pull/2832)

hscontrol/mapper/batcher_lockfree.go

@@ -31,6 +31,7 @@ type LockFreeBatcher struct {
 	workCh     chan work
 	workChOnce sync.Once // Ensures workCh is only closed once
 	done       chan struct{}
+	doneOnce   sync.Once // Ensures done is only closed once
 
 	// Batching state
 	pendingChanges *xsync.Map[types.NodeID, []change.Change]
@@ -151,10 +152,12 @@ func (b *LockFreeBatcher) Start() {
 }
 
 func (b *LockFreeBatcher) Close() {
-	// Signal shutdown to all goroutines
+	// Signal shutdown to all goroutines, only once
+	b.doneOnce.Do(func() {
 		if b.done != nil {
 			close(b.done)
 		}
+	})
 
 	// Only close workCh once using sync.Once to prevent races
 	b.workChOnce.Do(func() {

hscontrol/oidc.go

@@ -41,6 +41,7 @@ var (
 	errOIDCAllowedUsers  = errors.New(
 		"authenticated principal does not match any allowed user",
 	)
+	errOIDCUnverifiedEmail = errors.New("authenticated principal has an unverified email")
 )
 
 // RegistrationInfo contains both machine key and verifier information for OIDC validation.
@@ -264,17 +265,8 @@ func (a *AuthProviderOIDC) OIDCCallbackHandler(
 
 	// The user claims are now updated from the userinfo endpoint so we can verify the user
 	// against allowed emails, email domains, and groups.
-	if err := validateOIDCAllowedDomains(a.cfg.AllowedDomains, &claims); err != nil {
-		httpError(writer, err)
-		return
-	}
-
-	if err := validateOIDCAllowedGroups(a.cfg.AllowedGroups, &claims); err != nil {
-		httpError(writer, err)
-		return
-	}
-
-	if err := validateOIDCAllowedUsers(a.cfg.AllowedUsers, &claims); err != nil {
+	err = doOIDCAuthorization(a.cfg, &claims)
+	if err != nil {
 		httpError(writer, err)
 		return
 	}
@@ -434,7 +426,6 @@ func validateOIDCAllowedGroups(
 	allowedGroups []string,
 	claims *types.OIDCClaims,
 ) error {
-	if len(allowedGroups) > 0 {
 	for _, group := range allowedGroups {
 		if slices.Contains(claims.Groups, group) {
 			return nil
@@ -442,9 +433,6 @@ func validateOIDCAllowedGroups(
 	}
 
 	return NewHTTPError(http.StatusUnauthorized, "unauthorised group", errOIDCAllowedGroups)
-	}
-
-	return nil
 }
 
 // validateOIDCAllowedUsers checks that if AllowedUsers is provided,
@@ -453,14 +441,62 @@ func validateOIDCAllowedUsers(
 	allowedUsers []string,
 	claims *types.OIDCClaims,
 ) error {
-	if len(allowedUsers) > 0 &&
-		!slices.Contains(allowedUsers, claims.Email) {
+	if !slices.Contains(allowedUsers, claims.Email) {
 		return NewHTTPError(http.StatusUnauthorized, "unauthorised user", errOIDCAllowedUsers)
 	}
 
 	return nil
 }
 
+// doOIDCAuthorization applies authorization tests to claims.
+//
+// The following tests are always applied:
+//
+// - validateOIDCAllowedGroups
+//
+// The following tests are applied if cfg.EmailVerifiedRequired=false
+// or claims.email_verified=true:
+//
+// - validateOIDCAllowedDomains
+// - validateOIDCAllowedUsers
+//
+// NOTE that, contrary to the function name, validateOIDCAllowedUsers
+// only checks the email address -- not the username.
+func doOIDCAuthorization(
+	cfg *types.OIDCConfig,
+	claims *types.OIDCClaims,
+) error {
+	if len(cfg.AllowedGroups) > 0 {
+		err := validateOIDCAllowedGroups(cfg.AllowedGroups, claims)
+		if err != nil {
+			return err
+		}
+	}
+
+	trustEmail := !cfg.EmailVerifiedRequired || bool(claims.EmailVerified)
+
+	hasEmailTests := len(cfg.AllowedDomains) > 0 || len(cfg.AllowedUsers) > 0
+	if !trustEmail && hasEmailTests {
+		return NewHTTPError(http.StatusUnauthorized, "unverified email", errOIDCUnverifiedEmail)
+	}
+
+	if len(cfg.AllowedDomains) > 0 {
+		err := validateOIDCAllowedDomains(cfg.AllowedDomains, claims)
+		if err != nil {
+			return err
+		}
+	}
+
+	if len(cfg.AllowedUsers) > 0 {
+		err := validateOIDCAllowedUsers(cfg.AllowedUsers, claims)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
 // getRegistrationIDFromState retrieves the registration ID from the state.
 func (a *AuthProviderOIDC) getRegistrationIDFromState(state string) *types.RegistrationID {
 	regInfo, ok := a.registrationCache.Get(state)
@@ -493,7 +529,7 @@ func (a *AuthProviderOIDC) createOrUpdateUserFromClaim(
 		user = &types.User{}
 	}
 
-	user.FromClaim(claims)
+	user.FromClaim(claims, a.cfg.EmailVerifiedRequired)
 
 	if newUser {
 		user, c, err = a.h.state.CreateUser(*user)

hscontrol/oidc_test.go

@@ -0,0 +1,173 @@
+package hscontrol
+
+import (
+	"testing"
+
+	"github.com/juanfont/headscale/hscontrol/types"
+)
+
+func TestDoOIDCAuthorization(t *testing.T) {
+	testCases := []struct {
+		name    string
+		cfg     *types.OIDCConfig
+		claims  *types.OIDCClaims
+		wantErr bool
+	}{
+		{
+			name:    "verified email domain",
+			wantErr: false,
+			cfg: &types.OIDCConfig{
+				EmailVerifiedRequired: true,
+				AllowedDomains:        []string{"test.com"},
+				AllowedUsers:          []string{},
+				AllowedGroups:         []string{},
+			},
+			claims: &types.OIDCClaims{
+				Email:         "user@test.com",
+				EmailVerified: true,
+			},
+		},
+		{
+			name:    "verified email user",
+			wantErr: false,
+			cfg: &types.OIDCConfig{
+				EmailVerifiedRequired: true,
+				AllowedDomains:        []string{},
+				AllowedUsers:          []string{"user@test.com"},
+				AllowedGroups:         []string{},
+			},
+			claims: &types.OIDCClaims{
+				Email:         "user@test.com",
+				EmailVerified: true,
+			},
+		},
+		{
+			name:    "unverified email domain",
+			wantErr: true,
+			cfg: &types.OIDCConfig{
+				EmailVerifiedRequired: true,
+				AllowedDomains:        []string{"test.com"},
+				AllowedUsers:          []string{},
+				AllowedGroups:         []string{},
+			},
+			claims: &types.OIDCClaims{
+				Email:         "user@test.com",
+				EmailVerified: false,
+			},
+		},
+		{
+			name:    "group member",
+			wantErr: false,
+			cfg: &types.OIDCConfig{
+				EmailVerifiedRequired: true,
+				AllowedDomains:        []string{},
+				AllowedUsers:          []string{},
+				AllowedGroups:         []string{"test"},
+			},
+			claims: &types.OIDCClaims{Groups: []string{"test"}},
+		},
+		{
+			name:    "non group member",
+			wantErr: true,
+			cfg: &types.OIDCConfig{
+				EmailVerifiedRequired: true,
+				AllowedDomains:        []string{},
+				AllowedUsers:          []string{},
+				AllowedGroups:         []string{"nope"},
+			},
+			claims: &types.OIDCClaims{Groups: []string{"testo"}},
+		},
+		{
+			name:    "group member but bad domain",
+			wantErr: true,
+			cfg: &types.OIDCConfig{
+				EmailVerifiedRequired: true,
+				AllowedDomains:        []string{"user@good.com"},
+				AllowedUsers:          []string{},
+				AllowedGroups:         []string{"test group"},
+			},
+			claims: &types.OIDCClaims{Groups: []string{"test group"}, Email: "bad@bad.com", EmailVerified: true},
+		},
+		{
+			name:    "all checks pass",
+			wantErr: false,
+			cfg: &types.OIDCConfig{
+				EmailVerifiedRequired: true,
+				AllowedDomains:        []string{"test.com"},
+				AllowedUsers:          []string{"user@test.com"},
+				AllowedGroups:         []string{"test group"},
+			},
+			claims: &types.OIDCClaims{Groups: []string{"test group"}, Email: "user@test.com", EmailVerified: true},
+		},
+		{
+			name:    "all checks pass with unverified email",
+			wantErr: false,
+			cfg: &types.OIDCConfig{
+				EmailVerifiedRequired: false,
+				AllowedDomains:        []string{"test.com"},
+				AllowedUsers:          []string{"user@test.com"},
+				AllowedGroups:         []string{"test group"},
+			},
+			claims: &types.OIDCClaims{Groups: []string{"test group"}, Email: "user@test.com", EmailVerified: false},
+		},
+		{
+			name:    "fail on unverified email",
+			wantErr: true,
+			cfg: &types.OIDCConfig{
+				EmailVerifiedRequired: true,
+				AllowedDomains:        []string{"test.com"},
+				AllowedUsers:          []string{"user@test.com"},
+				AllowedGroups:         []string{"test group"},
+			},
+			claims: &types.OIDCClaims{Groups: []string{"test group"}, Email: "user@test.com", EmailVerified: false},
+		},
+		{
+			name:    "unverified email user only",
+			wantErr: true,
+			cfg: &types.OIDCConfig{
+				EmailVerifiedRequired: true,
+				AllowedDomains:        []string{},
+				AllowedUsers:          []string{"user@test.com"},
+				AllowedGroups:         []string{},
+			},
+			claims: &types.OIDCClaims{
+				Email:         "user@test.com",
+				EmailVerified: false,
+			},
+		},
+		{
+			name:    "no filters configured",
+			wantErr: false,
+			cfg: &types.OIDCConfig{
+				EmailVerifiedRequired: true,
+				AllowedDomains:        []string{},
+				AllowedUsers:          []string{},
+				AllowedGroups:         []string{},
+			},
+			claims: &types.OIDCClaims{
+				Email:         "anyone@anywhere.com",
+				EmailVerified: false,
+			},
+		},
+		{
+			name:    "multiple allowed groups second matches",
+			wantErr: false,
+			cfg: &types.OIDCConfig{
+				EmailVerifiedRequired: true,
+				AllowedDomains:        []string{},
+				AllowedUsers:          []string{},
+				AllowedGroups:         []string{"group1", "group2", "group3"},
+			},
+			claims: &types.OIDCClaims{Groups: []string{"group2"}},
+		},
+	}
+
+	for _, tC := range testCases {
+		t.Run(tC.name, func(t *testing.T) {
+			err := doOIDCAuthorization(tC.cfg, tC.claims)
+			if ((err != nil) && !tC.wantErr) || ((err == nil) && tC.wantErr) {
+				t.Errorf("bad authorization: %s > want=%v | got=%v", tC.name, tC.wantErr, err)
+			}
+		})
+	}
+}

hscontrol/types/config.go

@@ -185,6 +185,7 @@ type OIDCConfig struct {
 	AllowedDomains             []string
 	AllowedUsers               []string
 	AllowedGroups              []string
+	EmailVerifiedRequired      bool
 	Expiry                     time.Duration
 	UseExpiryFromToken         bool
 	PKCE                       PKCEConfig
@@ -384,6 +385,7 @@ func LoadConfig(path string, isFile bool) error {
 	viper.SetDefault("oidc.use_expiry_from_token", false)
 	viper.SetDefault("oidc.pkce.enabled", false)
 	viper.SetDefault("oidc.pkce.method", "S256")
+	viper.SetDefault("oidc.email_verified_required", true)
 
 	viper.SetDefault("logtail.enabled", false)
 	viper.SetDefault("randomize_client_port", false)
@@ -1030,6 +1032,7 @@ func LoadServerConfig() (*Config, error) {
 			AllowedDomains:        viper.GetStringSlice("oidc.allowed_domains"),
 			AllowedUsers:          viper.GetStringSlice("oidc.allowed_users"),
 			AllowedGroups:         viper.GetStringSlice("oidc.allowed_groups"),
+			EmailVerifiedRequired: viper.GetBool("oidc.email_verified_required"),
 			Expiry: func() time.Duration {
 				// if set to 0, we assume no expiry
 				if value := viper.GetString("oidc.expiry"); value == "0" {

hscontrol/types/users.go

@@ -353,7 +353,7 @@ type OIDCUserInfo struct {
 
 // FromClaim overrides a User from OIDC claims.
 // All fields will be updated, except for the ID.
-func (u *User) FromClaim(claims *OIDCClaims) {
+func (u *User) FromClaim(claims *OIDCClaims, emailVerifiedRequired bool) {
 	err := util.ValidateUsername(claims.Username)
 	if err == nil {
 		u.Name = claims.Username
@@ -361,7 +361,7 @@ func (u *User) FromClaim(claims *OIDCClaims) {
 		log.Debug().Caller().Err(err).Msgf("Username %s is not valid", claims.Username)
 	}
 
-	if claims.EmailVerified {
+	if claims.EmailVerified || !FlexibleBoolean(emailVerifiedRequired) {
 		_, err = mail.ParseAddress(claims.Email)
 		if err == nil {
 			u.Email = claims.Email

hscontrol/types/users_test.go

@@ -293,10 +293,12 @@ func TestOIDCClaimsJSONToUser(t *testing.T) {
 	tests := []struct {
 		name                  string
 		jsonstr               string
+		emailVerifiedRequired bool
 		want                  User
 	}{
 		{
 			name:                  "normal-bool",
+			emailVerifiedRequired: true,
 			jsonstr: `
 {
   "sub": "test",
@@ -315,6 +317,7 @@ func TestOIDCClaimsJSONToUser(t *testing.T) {
 		},
 		{
 			name:                  "string-bool-true",
+			emailVerifiedRequired: true,
 			jsonstr: `
 {
   "sub": "test2",
@@ -333,6 +336,7 @@ func TestOIDCClaimsJSONToUser(t *testing.T) {
 		},
 		{
 			name:                  "string-bool-false",
+			emailVerifiedRequired: true,
 			jsonstr: `
 {
   "sub": "test3",
@@ -348,9 +352,29 @@ func TestOIDCClaimsJSONToUser(t *testing.T) {
 				},
 			},
 		},
+		{
+			name:                  "allow-unverified-email",
+			emailVerifiedRequired: false,
+			jsonstr: `
+{
+  "sub": "test4",
+  "email": "test4@test.no",
+  "email_verified": "false"
+}
+			`,
+			want: User{
+				Provider: util.RegisterMethodOIDC,
+				Email:    "test4@test.no",
+				ProviderIdentifier: sql.NullString{
+					String: "/test4",
+					Valid:  true,
+				},
+			},
+		},
 		{
 			// From https://github.com/juanfont/headscale/issues/2333
 			name:                  "okta-oidc-claim-20250121",
+			emailVerifiedRequired: true,
 			jsonstr: `
 {
   "sub": "00u7dr4qp7XXXXXXXXXX",
@@ -375,6 +399,7 @@ func TestOIDCClaimsJSONToUser(t *testing.T) {
 			want: User{
 				Provider:    util.RegisterMethodOIDC,
 				DisplayName: "Tim Horton",
+				Email:       "",
 				Name:        "tim.horton@company.com",
 				ProviderIdentifier: sql.NullString{
 					String: "https://sso.company.com/oauth2/default/00u7dr4qp7XXXXXXXXXX",
@@ -385,6 +410,7 @@ func TestOIDCClaimsJSONToUser(t *testing.T) {
 		{
 			// From https://github.com/juanfont/headscale/issues/2333
 			name:                  "okta-oidc-claim-20250121",
+			emailVerifiedRequired: true,
 			jsonstr: `
 {
   "aud": "79xxxxxx-xxxx-xxxx-xxxx-892146xxxxxx",
@@ -409,6 +435,7 @@ func TestOIDCClaimsJSONToUser(t *testing.T) {
 				Provider:    util.RegisterMethodOIDC,
 				DisplayName: "XXXXXX XXXX",
 				Name:        "user@domain.com",
+				Email:       "",
 				ProviderIdentifier: sql.NullString{
 					String: "https://login.microsoftonline.com/v2.0/I-70OQnj3TogrNSfkZQqB3f7dGwyBWSm1dolHNKrMzQ",
 					Valid:  true,
@@ -418,6 +445,7 @@ func TestOIDCClaimsJSONToUser(t *testing.T) {
 		{
 			// From https://github.com/juanfont/headscale/issues/2333
 			name:                  "casby-oidc-claim-20250513",
+			emailVerifiedRequired: true,
 			jsonstr: `
 			{
   "sub": "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx",
@@ -458,7 +486,7 @@ func TestOIDCClaimsJSONToUser(t *testing.T) {
 
 			var user User
 
-			user.FromClaim(&got)
+			user.FromClaim(&got, tt.emailVerifiedRequired)
 			if diff := cmp.Diff(user, tt.want); diff != "" {
 				t.Errorf("TestOIDCClaimsJSONToUser() mismatch (-want +got):\n%s", diff)
 			}