386 lines
12 KiB
Go
386 lines
12 KiB
Go
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package auth_connectors
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import (
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"context"
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"crypto/tls"
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"encoding/json"
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"errors"
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"fmt"
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"net"
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"oc-auth/conf"
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"strings"
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"sync"
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"time"
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"github.com/coocood/freecache"
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"github.com/go-ldap/ldap/v3"
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"github.com/i-core/rlog"
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"go.uber.org/zap"
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)
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var (
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// errInvalidCredentials is an error that happens when a user's password is invalid.
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errInvalidCredentials = fmt.Errorf("invalid credentials")
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// errConnectionTimeout is an error that happens when no one LDAP endpoint responds.
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errConnectionTimeout = fmt.Errorf("connection timeout")
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// errMissedUsername is an error that happens
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errMissedUsername = errors.New("username is missed")
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// errUnknownUsername is an error that happens
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errUnknownUsername = errors.New("unknown username")
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)
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type conn interface {
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Bind(bindDN, password string) error
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SearchUser(user string, attrs ...string) ([]map[string]interface{}, error)
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SearchUserRoles(user string, attrs ...string) ([]map[string]interface{}, error)
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Close() error
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}
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type connector interface {
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Connect(ctx context.Context, addr string) (conn, error)
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}
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// Config is a LDAP configuration.
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type Config struct {
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Endpoints []string `envconfig:"endpoints" required:"true" desc:"a LDAP's server URLs as \"<address>:<port>\""`
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BindDN string `envconfig:"binddn" desc:"a LDAP bind DN"`
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BindPass string `envconfig:"bindpw" json:"-" desc:"a LDAP bind password"`
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BaseDN string `envconfig:"basedn" required:"true" desc:"a LDAP base DN for searching users"`
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AttrClaims map[string]string `envconfig:"attr_claims" default:"name:name,sn:family_name,givenName:given_name,mail:email" desc:"a mapping of LDAP attributes to OpenID connect claims"`
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RoleBaseDN string `envconfig:"role_basedn" required:"true" desc:"a LDAP base DN for searching roles"`
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RoleAttr string `envconfig:"role_attr" default:"description" desc:"a LDAP group's attribute that contains a role's name"`
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RoleClaim string `envconfig:"role_claim" default:"https://github.com/i-core/werther/claims/roles" desc:"a name of an OpenID Connect claim that contains user roles"`
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CacheSize int `envconfig:"cache_size" default:"512" desc:"a user info cache's size in KiB"`
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CacheTTL time.Duration `envconfig:"cache_ttl" default:"30m" desc:"a user info cache TTL"`
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IsTLS bool `envconfig:"is_tls" default:"false" desc:"should LDAP connection be established via TLS"`
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FlatRoleClaims bool `envconfig:"flat_role_claims" desc:"add roles claim as single list"`
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}
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// New creates a new LDAP client.
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func New() *Client {
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cnf := Config{
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Endpoints: strings.Split(conf.GetConfig().LDAPEndpoints, ","),
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BindDN: conf.GetConfig().LDAPBindDN,
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BindPass: conf.GetConfig().LDAPBindPW,
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BaseDN: conf.GetConfig().LDAPBaseDN,
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RoleBaseDN: conf.GetConfig().LDAPRoleBaseDN,
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}
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return &Client{
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Config: cnf,
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connector: &ldapConnector{BaseDN: cnf.BaseDN, RoleBaseDN: cnf.RoleBaseDN, IsTLS: cnf.IsTLS},
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cache: freecache.NewCache(cnf.CacheSize * 1024),
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}
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}
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type Client struct {
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Config
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connector connector
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cache *freecache.Cache
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}
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func (cli *Client) Authenticate(ctx context.Context, username, password string) (bool, error) {
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if username == "" || password == "" {
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return false, nil
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}
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var cancel context.CancelFunc
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ctx, cancel = context.WithCancel(ctx)
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cn, ok := <-cli.connect(ctx)
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cancel()
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if !ok {
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return false, errConnectionTimeout
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}
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defer cn.Close()
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// Find a user DN by his or her username.
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details, err := cli.findBasicUserDetails(cn, username, []string{"dn"})
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if err != nil {
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return false, err
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}
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if details == nil {
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return false, nil
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}
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if err := cn.Bind(details["dn"].(string), password); err != nil {
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if err == errInvalidCredentials {
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return false, nil
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}
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return false, err
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}
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// Clear the claims' cache because of possible re-authentication. We don't want stale claims after re-login.
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if ok := cli.cache.Del([]byte(username)); ok {
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log := rlog.FromContext(ctx)
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log.Debug("Cleared user's OIDC claims in the cache")
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}
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return true, nil
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}
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// Claim is the FindOIDCClaims result struct
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type LDAPClaim struct {
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Code string // the root claim name
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Name string // the claim name
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Value interface{} // the value
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}
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// FindOIDCClaims finds all OIDC claims for a user.
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func (cli *Client) FindOIDCClaims(ctx context.Context, username string) ([]LDAPClaim, error) {
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if username == "" {
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return nil, errMissedUsername
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}
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log := rlog.FromContext(ctx).Sugar()
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// Retrieving from LDAP is slow. So, we try to get claims for the given username from the cache.
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switch cdata, err := cli.cache.Get([]byte(username)); err {
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case nil:
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var claims []LDAPClaim
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if err = json.Unmarshal(cdata, &claims); err != nil {
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log.Info("Failed to unmarshal user's OIDC claims", zap.Error(err), "data", cdata)
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return nil, err
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}
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log.Debugw("Retrieved user's OIDC claims from the cache", "claims", claims)
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return claims, nil
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case freecache.ErrNotFound:
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log.Debug("User's OIDC claims is not found in the cache")
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default:
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log.Infow("Failed to retrieve user's OIDC claims from the cache", zap.Error(err))
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}
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// Try to make multiple TCP connections to the LDAP server for getting claims.
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// Accept the first one, and cancel others.
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var cancel context.CancelFunc
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ctx, cancel = context.WithCancel(ctx)
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cn, ok := <-cli.connect(ctx)
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cancel()
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if !ok {
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return nil, errConnectionTimeout
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}
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defer cn.Close()
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// We need to find LDAP attribute's names for all required claims.
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attrs := []string{"dn"}
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for k := range cli.AttrClaims {
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attrs = append(attrs, k)
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}
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// Find the attributes in the LDAP server.
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details, err := cli.findBasicUserDetails(cn, username, attrs)
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if err != nil {
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return nil, err
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}
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if details == nil {
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return nil, errUnknownUsername
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}
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log.Infow("Retrieved user's info from LDAP", "details", details)
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// Transform the retrieved attributes to corresponding claims.
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claims := make([]LDAPClaim, 0, len(details))
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for attr, v := range details {
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if claim, ok := cli.AttrClaims[attr]; ok {
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claims = append(claims, LDAPClaim{claim, claim, v})
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}
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}
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// User's roles is stored in LDAP as groups. We find all groups in a role's DN
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// that include the user as a member.
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entries, err := cn.SearchUserRoles(fmt.Sprintf("%s", details["dn"]), "dn", cli.RoleAttr)
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if err != nil {
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return nil, err
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}
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roles := make(map[string]interface{})
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for _, entry := range entries {
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roleDN, ok := entry["dn"].(string)
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if !ok || roleDN == "" {
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log.Infow("No required LDAP attribute for a role", "ldapAttribute", "dn", "entry", entry)
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continue
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}
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if entry[cli.RoleAttr] == nil {
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log.Infow("No required LDAP attribute for a role", "ldapAttribute", cli.RoleAttr, "roleDN", roleDN)
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continue
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}
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// Ensure that a role's DN is inside of the role's base DN.
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// It's sufficient to compare the DN's suffix with the base DN.
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n, k := len(roleDN), len(cli.RoleBaseDN)
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if n < k || !strings.EqualFold(roleDN[n-k:], cli.RoleBaseDN) {
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panic("You should never see that")
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}
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// The DN without the role's base DN must contain a CN and OU
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// where the CN is for uniqueness only, and the OU is an application id.
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path := strings.Split(roleDN[:n-k-1], ",")
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if len(path) != 2 {
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log.Infow("A role's DN without the role's base DN must contain two nodes only",
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"roleBaseDN", cli.RoleBaseDN, "roleDN", roleDN)
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continue
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}
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appID := path[1][len("OU="):]
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var appRoles []interface{}
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if v := roles[appID]; v != nil {
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appRoles = v.([]interface{})
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}
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appRoles = append(appRoles, entry[cli.RoleAttr])
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roles[appID] = appRoles
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}
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claims = append(claims, LDAPClaim{cli.RoleClaim, cli.RoleClaim, roles})
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if cli.FlatRoleClaims {
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for appID, appRoles := range roles {
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claims = append(claims, LDAPClaim{cli.RoleClaim, cli.RoleClaim + "/" + appID, appRoles})
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}
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}
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// Save the claims in the cache for future queries.
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cdata, err := json.Marshal(claims)
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if err != nil {
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log.Infow("Failed to marshal user's OIDC claims for caching", zap.Error(err), "claims", claims)
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}
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if err = cli.cache.Set([]byte(username), cdata, int(cli.CacheTTL.Seconds())); err != nil {
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log.Infow("Failed to store user's OIDC claims into the cache", zap.Error(err), "claims", claims)
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}
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return claims, nil
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}
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func (cli *Client) connect(ctx context.Context) <-chan conn {
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var (
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wg sync.WaitGroup
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ch = make(chan conn)
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)
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wg.Add(len(cli.Endpoints))
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for _, addr := range cli.Endpoints {
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go func(addr string) {
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defer wg.Done()
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cn, err := cli.connector.Connect(ctx, addr)
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if err != nil {
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fmt.Println("Failed to create a LDAP connection", "address", addr)
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return
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}
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select {
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case <-ctx.Done():
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cn.Close()
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fmt.Println("a LDAP connection is cancelled", "address", addr)
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return
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case ch <- cn:
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}
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}(addr)
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}
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go func() {
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wg.Wait()
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close(ch)
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}()
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return ch
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}
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// findBasicUserDetails finds user's LDAP attributes that were specified. It returns nil if no such user.
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func (cli *Client) findBasicUserDetails(cn conn, username string, attrs []string) (map[string]interface{}, error) {
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if cli.BindDN != "" {
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// We need to login to a LDAP server with a service account for retrieving user data.
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if err := cn.Bind(cli.BindDN, cli.BindPass); err != nil {
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return nil, errors.New(err.Error() + " : failed to login to a LDAP woth a service account")
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}
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}
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entries, err := cn.SearchUser(username, attrs...)
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if err != nil {
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return nil, err
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}
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if len(entries) != 1 {
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// We didn't find the user.
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return nil, nil
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}
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var (
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entry = entries[0]
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details = make(map[string]interface{})
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)
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for _, attr := range attrs {
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if v, ok := entry[attr]; ok {
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details[attr] = v
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}
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}
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return details, nil
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}
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type ldapConnector struct {
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BaseDN string
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RoleBaseDN string
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IsTLS bool
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}
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func (c *ldapConnector) Connect(ctx context.Context, addr string) (conn, error) {
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d := net.Dialer{Timeout: ldap.DefaultTimeout}
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tcpcn, err := d.DialContext(ctx, "tcp", addr)
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if err != nil {
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return nil, err
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}
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if c.IsTLS {
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tlscn, err := tls.DialWithDialer(&d, "tcp", addr, nil)
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if err != nil {
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return nil, err
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}
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tcpcn = tlscn
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}
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ldapcn := ldap.NewConn(tcpcn, c.IsTLS)
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ldapcn.Start()
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return &ldapConn{Conn: ldapcn, BaseDN: c.BaseDN, RoleBaseDN: c.RoleBaseDN}, nil
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}
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type ldapConn struct {
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*ldap.Conn
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BaseDN string
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RoleBaseDN string
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}
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func (c *ldapConn) Bind(bindDN, password string) error {
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err := c.Conn.Bind(bindDN, password)
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if ldapErr, ok := err.(*ldap.Error); ok && ldapErr.ResultCode == ldap.LDAPResultInvalidCredentials {
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return errInvalidCredentials
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}
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return err
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}
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func (c *ldapConn) SearchUser(user string, attrs ...string) ([]map[string]interface{}, error) {
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query := fmt.Sprintf(
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"(&(|(objectClass=organizationalPerson)(objectClass=inetOrgPerson))"+
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"(|(uid=%[1]s)(mail=%[1]s)(userPrincipalName=%[1]s)(sAMAccountName=%[1]s)))", user)
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return c.searchEntries(c.BaseDN, query, attrs)
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}
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func (c *ldapConn) SearchUserRoles(user string, attrs ...string) ([]map[string]interface{}, error) {
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query := fmt.Sprintf("(|"+
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"(&(|(objectClass=group)(objectClass=groupOfNames))(member=%[1]s))"+
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"(&(objectClass=groupOfUniqueNames)(uniqueMember=%[1]s))"+
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")", user)
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return c.searchEntries(c.RoleBaseDN, query, attrs)
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||
|
|
}
|
||
|
|
|
||
|
|
// searchEntries executes a LDAP query, and returns a result as entries where each entry is mapping of LDAP attributes.
|
||
|
|
func (c *ldapConn) searchEntries(baseDN, query string, attrs []string) ([]map[string]interface{}, error) {
|
||
|
|
req := ldap.NewSearchRequest(baseDN, ldap.ScopeWholeSubtree, ldap.NeverDerefAliases, 0, 0, false, query, attrs, nil)
|
||
|
|
res, err := c.Search(req)
|
||
|
|
if err != nil {
|
||
|
|
return nil, err
|
||
|
|
}
|
||
|
|
|
||
|
|
var entries []map[string]interface{}
|
||
|
|
for _, v := range res.Entries {
|
||
|
|
entry := map[string]interface{}{"dn": v.DN}
|
||
|
|
for _, attr := range v.Attributes {
|
||
|
|
// We need the first value only for the named attribute.
|
||
|
|
entry[attr.Name] = attr.Values[0]
|
||
|
|
}
|
||
|
|
entries = append(entries, entry)
|
||
|
|
}
|
||
|
|
return entries, nil
|
||
|
|
}
|