headscale/hscontrol/types/users.go

package types

import (
	"cmp"
	"database/sql"
	"encoding/json"
	"errors"
	"fmt"
	"net/mail"
	"net/url"
	"strconv"
	"strings"
	"time"

	"github.com/juanfont/headscale/hscontrol/util"
	"github.com/juanfont/headscale/hscontrol/util/zlog/zf"
	"github.com/rs/zerolog"
	"github.com/rs/zerolog/log"
	"gorm.io/gorm"
	"tailscale.com/tailcfg"
)

// ErrCannotParseBoolean is returned when a value cannot be parsed as boolean.
var ErrCannotParseBoolean = errors.New("cannot parse value as boolean")

// ErrCannotParseStringSlice is returned when a value cannot be parsed as string or []string.
var ErrCannotParseStringSlice = errors.New("cannot parse value as string or []string")

type UserID uint64

type Users []User

const (
	// TaggedDevicesUserID is the special user ID for tagged devices.
	// This ID is used when rendering tagged nodes in the Tailscale protocol.
	TaggedDevicesUserID = 2147455555
)

// TaggedDevices is a special user used in [tailcfg.MapResponse] for tagged nodes.
// Tagged nodes don't belong to a real user - the tag is their identity.
// This special user ID is used when rendering tagged nodes in the Tailscale protocol.
var TaggedDevices = User{
	Model:       gorm.Model{ID: TaggedDevicesUserID},
	Name:        "tagged-devices",
	DisplayName: "Tagged Devices",
}

func (u Users) String() string {
	var sb strings.Builder
	sb.WriteString("[ ")

	for _, user := range u {
		fmt.Fprintf(&sb, "%d: %s, ", user.ID, user.Name)
	}

	sb.WriteString(" ]")

	return sb.String()
}

// User is the way Headscale implements the concept of users in Tailscale
//
// At the end of the day, users in Tailscale are some kind of 'bubbles' or users
// that contain our machines.
type User struct {
	gorm.Model //nolint:embeddedstructfieldcheck

	// The index `idx_name_provider_identifier` is to enforce uniqueness
	// between Name and ProviderIdentifier. This ensures that
	// you can have multiple users with the same name in OIDC,
	// but not if you only run with CLI users.

	// Name (username) for the user, is used if email is empty
	// Should not be used, please use [User.Username].
	// It is unique if [User.ProviderIdentifier] is not set.
	Name string

	// Typically the full name of the user
	DisplayName string

	// Email of the user
	// Should not be used, please use [User.Username].
	Email string

	// ProviderIdentifier is a unique or not set identifier of the
	// user from OIDC. It is the combination of `iss`
	// and `sub` claim in the OIDC token.
	// It is unique if set.
	// It is unique together with [User.Name].
	ProviderIdentifier sql.NullString

	// Provider is the origin of the user account,
	// same as RegistrationMethod, without authkey.
	Provider string

	// TODO(kradalby): See if we can fill in Gravatar here.
	ProfilePicURL string
}

func (u *User) StringID() string {
	if u == nil {
		return ""
	}

	return strconv.FormatUint(uint64(u.ID), 10)
}

// TypedID returns a pointer to the user's ID as a [UserID] type.
// This is a convenience method to avoid ugly casting like ptr.To(types.UserID(user.ID)).
func (u *User) TypedID() *UserID {
	uid := UserID(u.ID)
	return &uid
}

// Username is the main way to get the username of a user,
// it will return the email if it exists, the name if it exists,
// the OIDCIdentifier if it exists, and the ID if nothing else exists.
// Email and OIDCIdentifier will be set when the user has headscale
// enabled with OIDC, which means that there is a domain involved which
// should be used throughout headscale, in information returned to the
// user and the Policy engine.
func (u *User) Username() string {
	return cmp.Or(
		u.Email,
		u.Name,
		u.ProviderIdentifier.String,
		u.StringID(),
	)
}

// Display returns the [User.DisplayName] if it exists, otherwise
// it will return the [User.Username].
func (u *User) Display() string {
	return cmp.Or(u.DisplayName, u.Username())
}

// Username returns the user's login name via the view; see [User.Username].
func (v UserView) Username() string {
	if !v.Valid() {
		return ""
	}

	return v.ж.Username()
}

// Display returns the user's display name via the view; see [User.Display].
func (v UserView) Display() string {
	if !v.Valid() {
		return ""
	}

	return v.ж.Display()
}

// CreatedAt returns when the user was created.
func (v UserView) CreatedAt() time.Time {
	if !v.Valid() {
		return time.Time{}
	}

	return v.ж.CreatedAt
}

func (u *User) TailscaleUser() tailcfg.User {
	return tailcfg.User{
		ID:            tailcfg.UserID(u.ID), //nolint:gosec // UserID is bounded
		DisplayName:   u.Display(),
		ProfilePicURL: u.ProfilePicURL,
		Created:       u.CreatedAt,
	}
}

func (u UserView) TailscaleUser() tailcfg.User {
	return u.ж.TailscaleUser()
}

// ID returns the user's ID.
// This is a custom accessor because [gorm.Model].ID is embedded
// and the viewer generator doesn't always produce it.
func (u UserView) ID() uint {
	return u.ж.ID
}

func (u *User) TailscaleLogin() tailcfg.Login {
	return tailcfg.Login{
		ID:            tailcfg.LoginID(u.ID), //nolint:gosec // safe conversion for user ID
		Provider:      u.Provider,
		LoginName:     u.Username(),
		DisplayName:   u.Display(),
		ProfilePicURL: u.ProfilePicURL,
	}
}

func (u UserView) TailscaleLogin() tailcfg.Login {
	return u.ж.TailscaleLogin()
}

func (u *User) TailscaleUserProfile() tailcfg.UserProfile {
	return tailcfg.UserProfile{
		ID:            tailcfg.UserID(u.ID), //nolint:gosec // UserID is bounded
		LoginName:     u.Username(),
		DisplayName:   u.Display(),
		ProfilePicURL: u.ProfilePicURL,
	}
}

func (u UserView) TailscaleUserProfile() tailcfg.UserProfile {
	return u.ж.TailscaleUserProfile()
}

// MarshalZerologObject implements [zerolog.LogObjectMarshaler] for safe logging.
func (u *User) MarshalZerologObject(e *zerolog.Event) {
	if u == nil {
		return
	}

	e.Uint(zf.UserID, u.ID)
	e.Str(zf.UserName, u.Username())
	e.Str(zf.UserDisplay, u.Display())

	if u.Provider != "" {
		e.Str(zf.UserProvider, u.Provider)
	}
}

// MarshalZerologObject implements [zerolog.LogObjectMarshaler] for [UserView].
func (u UserView) MarshalZerologObject(e *zerolog.Event) {
	if !u.Valid() {
		return
	}

	u.ж.MarshalZerologObject(e)
}

// FlexibleStringSlice handles OIDC providers (e.g. JumpCloud) that return the
// groups claim as a plain string when the user belongs to a single group,
// instead of a single-element array.
type FlexibleStringSlice []string

func (f *FlexibleStringSlice) UnmarshalJSON(data []byte) error {
	var arr []string

	err := json.Unmarshal(data, &arr)
	if err == nil {
		*f = arr
		return nil
	}

	var single string

	err = json.Unmarshal(data, &single)
	if err == nil {
		*f = []string{single}
		return nil
	}

	return fmt.Errorf("%w: %s", ErrCannotParseStringSlice, string(data))
}

// FlexibleBoolean handles JumpCloud's JSON where email_verified is returned as a
// string "true" or "false" instead of a boolean.
// This maps bool to a specific type with a custom unmarshaler to
// ensure we can decode it from a string.
type FlexibleBoolean bool

func (bit *FlexibleBoolean) UnmarshalJSON(data []byte) error {
	var val any

	err := json.Unmarshal(data, &val)
	if err != nil {
		return fmt.Errorf("unmarshalling data: %w", err)
	}

	switch v := val.(type) {
	case bool:
		*bit = FlexibleBoolean(v)
	case string:
		pv, err := strconv.ParseBool(v)
		if err != nil {
			return fmt.Errorf("parsing %s as boolean: %w", v, err)
		}

		*bit = FlexibleBoolean(pv)

	default:
		return fmt.Errorf("%w: %v", ErrCannotParseBoolean, v)
	}

	return nil
}

type OIDCClaims struct {
	// Sub is the user's unique identifier at the provider.
	Sub string `json:"sub"`
	Iss string `json:"iss"`

	// Name is the user's full name.
	Name              string              `json:"name,omitempty"`
	Groups            FlexibleStringSlice `json:"groups,omitempty"`
	Email             string              `json:"email,omitempty"`
	EmailVerified     FlexibleBoolean     `json:"email_verified,omitempty"`
	ProfilePictureURL string              `json:"picture,omitempty"`
	Username          string              `json:"preferred_username,omitempty"`
}

// Identifier returns a unique identifier string combining the [OIDCClaims.Iss] and [OIDCClaims.Sub] claims.
// The format depends on whether [OIDCClaims.Iss] is a URL or not:
// - For URLs: Joins the URL and sub path (e.g., "https://example.com/sub")
// - For non-URLs: Joins with a slash (e.g., "oidc/sub")
// - For empty [OIDCClaims.Iss]: Returns just "sub"
// - For empty [OIDCClaims.Sub]: Returns just the Issuer
// - For both empty: Returns empty string
//
// The result is cleaned using [CleanIdentifier] to ensure consistent formatting.
func (c *OIDCClaims) Identifier() string {
	// Handle empty components special cases
	if c.Iss == "" && c.Sub == "" {
		return ""
	}

	if c.Iss == "" {
		return CleanIdentifier(c.Sub)
	}

	if c.Sub == "" {
		return CleanIdentifier(c.Iss)
	}

	// We'll use the raw values and let CleanIdentifier handle all the whitespace
	issuer := c.Iss
	subject := c.Sub

	var result string
	// Always use simple string concatenation with a slash separator.
	// url.JoinPath resolves path-traversal segments like ".." and ".",
	// which can silently drop the subject and cause identifier collisions
	// between distinct OIDC users (e.g., Sub=".." produces the same
	// identifier as an empty Sub).
	issuer = strings.TrimSuffix(issuer, "/")
	subject = strings.TrimPrefix(subject, "/")
	result = issuer + "/" + subject

	// Clean the result and return it
	return CleanIdentifier(result)
}

// CleanIdentifier cleans a potentially malformed identifier by removing double slashes
// while preserving protocol specifications like http://. This function will:
// - Trim all whitespace from the beginning and end of the identifier
// - Remove whitespace within path segments
// - Preserve the scheme (http://, https://, etc.) for URLs
// - Remove any duplicate slashes in the path
// - Remove empty path segments
// - For non-URL identifiers, it joins non-empty segments with a single slash
// - Returns empty string for identifiers with only slashes
// - Normalize URL schemes to lowercase.
func CleanIdentifier(identifier string) string {
	if identifier == "" {
		return identifier
	}

	// Trim leading/trailing whitespace
	identifier = strings.TrimSpace(identifier)

	// Handle URLs with schemes
	u, err := url.Parse(identifier)
	if err == nil && u.Scheme != "" {
		// Clean path by removing empty segments and whitespace within segments
		if cleanParts := cleanSlashSegments(u.Path); len(cleanParts) == 0 {
			u.Path = ""
		} else {
			u.Path = "/" + strings.Join(cleanParts, "/")
		}
		// Ensure scheme is lowercase
		u.Scheme = strings.ToLower(u.Scheme)

		return u.String()
	}

	// Handle non-URL identifiers
	cleanParts := cleanSlashSegments(identifier)
	if len(cleanParts) == 0 {
		return ""
	}

	return strings.Join(cleanParts, "/")
}

// cleanSlashSegments splits s on '/', trims whitespace from each segment, and
// returns the non-empty segments.
func cleanSlashSegments(s string) []string {
	parts := strings.FieldsFunc(s, func(c rune) bool { return c == '/' })

	cleanParts := make([]string, 0, len(parts))
	for _, part := range parts {
		if part = strings.TrimSpace(part); part != "" {
			cleanParts = append(cleanParts, part)
		}
	}

	return cleanParts
}

type OIDCUserInfo struct {
	Sub               string              `json:"sub"`
	Name              string              `json:"name"`
	GivenName         string              `json:"given_name"`
	FamilyName        string              `json:"family_name"`
	PreferredUsername string              `json:"preferred_username"`
	Email             string              `json:"email"`
	EmailVerified     FlexibleBoolean     `json:"email_verified,omitempty"`
	Groups            FlexibleStringSlice `json:"groups"`
	Picture           string              `json:"picture"`
}

// FromClaim overrides a [User] from OIDC claims.
// All fields will be updated, except for the ID.
func (u *User) FromClaim(claims *OIDCClaims, emailVerifiedRequired bool) {
	err := util.ValidateUsername(claims.Username)
	if err == nil {
		u.Name = claims.Username
	} else {
		log.Debug().Caller().Err(err).Msgf("username %s is not valid", claims.Username)
	}

	if claims.EmailVerified || !FlexibleBoolean(emailVerifiedRequired) {
		_, err = mail.ParseAddress(claims.Email)
		if err == nil {
			u.Email = claims.Email
		}
	}

	// Get provider identifier
	identifier := claims.Identifier()
	// Ensure provider identifier always has a leading slash for backward compatibility
	if claims.Iss == "" && !strings.HasPrefix(identifier, "/") {
		identifier = "/" + identifier
	}

	u.ProviderIdentifier = sql.NullString{String: identifier, Valid: true}
	u.DisplayName = claims.Name
	u.ProfilePicURL = claims.ProfilePictureURL
	u.Provider = util.RegisterMethodOIDC
}