Support multiple LDAP OU's, smAccountName support (#9139)

Fixes #8532

cmd/config/identity/ldap/config.go

@@ -21,7 +21,8 @@ import (
 	"crypto/x509"
 	"errors"
 	"fmt"
-	"regexp"
+	"net"
+	"strings"
 	"time"
 
 	"github.com/minio/minio/cmd/config"
@@ -44,11 +45,15 @@ type Config struct {
 	STSExpiryDuration string `json:"stsExpiryDuration"`
 
 	// Format string for usernames
-	UsernameFormat string `json:"usernameFormat"`
+	UsernameFormat        string   `json:"usernameFormat"`
+	UsernameFormats       []string `json:"-"`
+	UsernameSearchFilter  string   `json:"-"`
+	UsernameSearchBaseDNS []string `json:"-"`
 
-	GroupSearchBaseDN  string `json:"groupSearchBaseDN"`
-	GroupSearchFilter  string `json:"groupSearchFilter"`
-	GroupNameAttribute string `json:"groupNameAttribute"`
+	GroupSearchBaseDN  string   `json:"groupSearchBaseDN"`
+	GroupSearchBaseDNS []string `json:"-"`
+	GroupSearchFilter  string   `json:"groupSearchFilter"`
+	GroupNameAttribute string   `json:"groupNameAttribute"`
 
 	stsExpiryDuration time.Duration // contains converted value
 	tlsSkipVerify     bool          // allows skipping TLS verification
@@ -58,23 +63,27 @@ type Config struct {
 
 // LDAP keys and envs.
 const (
-	ServerAddr         = "server_addr"
-	STSExpiry          = "sts_expiry"
-	UsernameFormat     = "username_format"
-	GroupSearchFilter  = "group_search_filter"
-	GroupNameAttribute = "group_name_attribute"
-	GroupSearchBaseDN  = "group_search_base_dn"
-	TLSSkipVerify      = "tls_skip_verify"
-	ServerInsecure     = "server_insecure"
+	ServerAddr           = "server_addr"
+	STSExpiry            = "sts_expiry"
+	UsernameFormat       = "username_format"
+	UsernameSearchFilter = "username_search_filter"
+	UsernameSearchBaseDN = "username_search_base_dn"
+	GroupSearchFilter    = "group_search_filter"
+	GroupNameAttribute   = "group_name_attribute"
+	GroupSearchBaseDN    = "group_search_base_dn"
+	TLSSkipVerify        = "tls_skip_verify"
+	ServerInsecure       = "server_insecure"
 
-	EnvServerAddr         = "MINIO_IDENTITY_LDAP_SERVER_ADDR"
-	EnvSTSExpiry          = "MINIO_IDENTITY_LDAP_STS_EXPIRY"
-	EnvTLSSkipVerify      = "MINIO_IDENTITY_LDAP_TLS_SKIP_VERIFY"
-	EnvServerInsecure     = "MINIO_IDENTITY_LDAP_SERVER_INSECURE"
-	EnvUsernameFormat     = "MINIO_IDENTITY_LDAP_USERNAME_FORMAT"
-	EnvGroupSearchFilter  = "MINIO_IDENTITY_LDAP_GROUP_SEARCH_FILTER"
-	EnvGroupNameAttribute = "MINIO_IDENTITY_LDAP_GROUP_NAME_ATTRIBUTE"
-	EnvGroupSearchBaseDN  = "MINIO_IDENTITY_LDAP_GROUP_SEARCH_BASE_DN"
+	EnvServerAddr           = "MINIO_IDENTITY_LDAP_SERVER_ADDR"
+	EnvSTSExpiry            = "MINIO_IDENTITY_LDAP_STS_EXPIRY"
+	EnvTLSSkipVerify        = "MINIO_IDENTITY_LDAP_TLS_SKIP_VERIFY"
+	EnvServerInsecure       = "MINIO_IDENTITY_LDAP_SERVER_INSECURE"
+	EnvUsernameFormat       = "MINIO_IDENTITY_LDAP_USERNAME_FORMAT"
+	EnvUsernameSearchFilter = "MINIO_IDENTITY_LDAP_USERNAME_SEARCH_FILTER"
+	EnvUsernameSearchBaseDN = "MINIO_IDENTITY_LDAP_USERNAME_SEARCH_BASE_DN"
+	EnvGroupSearchFilter    = "MINIO_IDENTITY_LDAP_GROUP_SEARCH_FILTER"
+	EnvGroupNameAttribute   = "MINIO_IDENTITY_LDAP_GROUP_NAME_ATTRIBUTE"
+	EnvGroupSearchBaseDN    = "MINIO_IDENTITY_LDAP_GROUP_SEARCH_BASE_DN"
 )
 
 // DefaultKVS - default config for LDAP config
@@ -85,11 +94,15 @@ var (
 			Value: "",
 		},
 		config.KV{
-			Key:   STSExpiry,
-			Value: "1h",
+			Key:   UsernameFormat,
+			Value: "",
 		},
 		config.KV{
-			Key:   UsernameFormat,
+			Key:   UsernameSearchFilter,
+			Value: "",
+		},
+		config.KV{
+			Key:   UsernameSearchBaseDN,
 			Value: "",
 		},
 		config.KV{
@@ -104,6 +117,10 @@ var (
 			Key:   GroupSearchBaseDN,
 			Value: "",
 		},
+		config.KV{
+			Key:   STSExpiry,
+			Value: "1h",
+		},
 		config.KV{
 			Key:   TLSSkipVerify,
 			Value: config.EnableOff,
@@ -115,16 +132,131 @@ var (
 	}
 )
 
+const (
+	dnDelimiter = ";"
+)
+
+func getGroups(conn *ldap.Conn, sreq *ldap.SearchRequest) ([]string, error) {
+	var groups []string
+	sres, err := conn.Search(sreq)
+	if err != nil {
+		return nil, err
+	}
+	for _, entry := range sres.Entries {
+		// We only queried one attribute,
+		// so we only look up the first one.
+		groups = append(groups, entry.Attributes[0].Values...)
+	}
+	return groups, nil
+}
+
+func (l *Config) bind(conn *ldap.Conn, username, password string) ([]string, error) {
+	var bindDNS = make([]string, len(l.UsernameFormats))
+	for i, usernameFormat := range l.UsernameFormats {
+		bindDN := fmt.Sprintf(usernameFormat, username)
+		// Bind with user credentials to validate the password
+		if err := conn.Bind(bindDN, password); err != nil {
+			return nil, err
+		}
+		bindDNS[i] = bindDN
+	}
+	return bindDNS, nil
+}
+
+var standardAttributes = []string{
+	"givenName",
+	"sn",
+	"cn",
+	"memberOf",
+	"email",
+}
+
+// Bind - binds to ldap, searches LDAP and returns list of groups.
+func (l *Config) Bind(username, password string) ([]string, error) {
+	conn, err := l.Connect()
+	if err != nil {
+		return nil, err
+	}
+	defer conn.Close()
+
+	bindDNS, err := l.bind(conn, username, password)
+	if err != nil {
+		return nil, err
+	}
+
+	var groups []string
+	if l.UsernameSearchFilter != "" {
+		for _, userSearchBase := range l.UsernameSearchBaseDNS {
+			filter := strings.Replace(l.UsernameSearchFilter, "%s",
+				ldap.EscapeFilter(username), -1)
+
+			searchRequest := ldap.NewSearchRequest(
+				userSearchBase,
+				ldap.ScopeWholeSubtree, ldap.NeverDerefAliases, 0, 0, false,
+				filter,
+				standardAttributes,
+				nil,
+			)
+
+			groups, err = getGroups(conn, searchRequest)
+			if err != nil {
+				return nil, err
+			}
+		}
+	}
+
+	if l.GroupSearchFilter != "" {
+		for _, groupSearchBase := range l.GroupSearchBaseDNS {
+			var filters []string
+			if l.GroupNameAttribute == "" {
+				filters = []string{strings.Replace(l.GroupSearchFilter, "%s",
+					ldap.EscapeFilter(username), -1)}
+			} else {
+				// With group name attribute specified, make sure to
+				// include search queries for CN distinguished name
+				for _, bindDN := range bindDNS {
+					filters = append(filters, strings.Replace(l.GroupSearchFilter, "%s",
+						ldap.EscapeFilter(bindDN), -1))
+				}
+			}
+			for _, filter := range filters {
+				searchRequest := ldap.NewSearchRequest(
+					groupSearchBase,
+					ldap.ScopeWholeSubtree, ldap.NeverDerefAliases, 0, 0, false,
+					filter,
+					standardAttributes,
+					nil,
+				)
+
+				var newGroups []string
+				newGroups, err = getGroups(conn, searchRequest)
+				if err != nil {
+					return nil, err
+				}
+
+				groups = append(groups, newGroups...)
+			}
+		}
+	}
+
+	return groups, nil
+}
+
 // Connect connect to ldap server.
 func (l *Config) Connect() (ldapConn *ldap.Conn, err error) {
 	if l == nil {
-		// Happens when LDAP is not configured.
-		return
+		return nil, errors.New("LDAP is not configured")
+	}
+
+	if _, _, err = net.SplitHostPort(l.ServerAddr); err != nil {
+		// User default LDAP port if none specified "636"
+		l.ServerAddr = net.JoinHostPort(l.ServerAddr, "636")
 	}
 
 	if l.serverInsecure {
 		return ldap.Dial("tcp", l.ServerAddr)
 	}
+
 	return ldap.DialTLS("tcp", l.ServerAddr, &tls.Config{
 		InsecureSkipVerify: l.tlsSkipVerify,
 		RootCAs:            l.rootCAs,
@@ -178,102 +310,44 @@ func Lookup(kvs config.KVS, rootCAs *x509.CertPool) (l Config, err error) {
 		}
 	}
 	if v := env.Get(EnvUsernameFormat, kvs.Get(UsernameFormat)); v != "" {
-		subs, err := NewSubstituter("username", "test")
-		if err != nil {
-			return l, err
+		if !strings.Contains(v, "%s") {
+			return l, errors.New("LDAP username format doesn't have '%s' substitution")
 		}
-		if _, err := subs.Substitute(v); err != nil {
-			return l, err
-		}
-		l.UsernameFormat = v
+		l.UsernameFormats = strings.Split(v, dnDelimiter)
 	} else {
 		return l, fmt.Errorf("'%s' cannot be empty and must have a value", UsernameFormat)
 	}
 
+	if v := env.Get(EnvUsernameSearchFilter, kvs.Get(UsernameSearchFilter)); v != "" {
+		if !strings.Contains(v, "%s") {
+			return l, errors.New("LDAP username search filter doesn't have '%s' substitution")
+		}
+		l.UsernameSearchFilter = v
+	}
+
+	if v := env.Get(EnvUsernameSearchBaseDN, kvs.Get(UsernameSearchBaseDN)); v != "" {
+		l.UsernameSearchBaseDNS = strings.Split(v, dnDelimiter)
+	}
+
 	grpSearchFilter := env.Get(EnvGroupSearchFilter, kvs.Get(GroupSearchFilter))
 	grpSearchNameAttr := env.Get(EnvGroupNameAttribute, kvs.Get(GroupNameAttribute))
 	grpSearchBaseDN := env.Get(EnvGroupSearchBaseDN, kvs.Get(GroupSearchBaseDN))
 
 	// Either all group params must be set or none must be set.
-	allNotSet := grpSearchFilter == "" && grpSearchNameAttr == "" && grpSearchBaseDN == ""
-	allSet := grpSearchFilter != "" && grpSearchNameAttr != "" && grpSearchBaseDN != ""
-	if !allNotSet && !allSet {
-		return l, errors.New("All group related parameters must be set")
+	var allSet bool
+	if grpSearchFilter != "" {
+		if grpSearchNameAttr == "" || grpSearchBaseDN == "" {
+			return l, errors.New("All group related parameters must be set")
+		}
+		allSet = true
 	}
 
 	if allSet {
-		subs, err := NewSubstituter("username", "test", "usernamedn", "test2")
-		if err != nil {
-			return l, err
-		}
-		if _, err := subs.Substitute(grpSearchFilter); err != nil {
-			return l, fmt.Errorf("Only username and usernamedn may be substituted in the group search filter string: %s", err)
-		}
 		l.GroupSearchFilter = grpSearchFilter
 		l.GroupNameAttribute = grpSearchNameAttr
-		subs, err = NewSubstituter("username", "test", "usernamedn", "test2")
-		if err != nil {
-			return l, err
-		}
-		if _, err := subs.Substitute(grpSearchBaseDN); err != nil {
-			return l, fmt.Errorf("Only username and usernamedn may be substituted in the base DN string: %s", err)
-		}
-		l.GroupSearchBaseDN = grpSearchBaseDN
+		l.GroupSearchBaseDNS = strings.Split(grpSearchBaseDN, dnDelimiter)
 	}
 
 	l.rootCAs = rootCAs
 	return l, nil
 }
-
-// Substituter - This type is to allow restricted runtime
-// substitutions of variables in LDAP configuration items during
-// runtime.
-type Substituter struct {
-	vals map[string]string
-}
-
-// NewSubstituter - sets up the substituter for usage, for e.g.:
-//
-//  subber := NewSubstituter("username", "john")
-func NewSubstituter(v ...string) (Substituter, error) {
-	if len(v)%2 != 0 {
-		return Substituter{}, errors.New("Need an even number of arguments")
-	}
-	vals := make(map[string]string)
-	for i := 0; i < len(v); i += 2 {
-		vals[v[i]] = v[i+1]
-	}
-	return Substituter{vals: vals}, nil
-}
-
-// Substitute - performs substitution on the given string `t`. Returns
-// an error if there are any variables in the input that do not have
-// values in the substituter. E.g.:
-//
-// subber.Substitute("uid=${username},cn=users,dc=example,dc=com")
-//
-// or
-//
-// subber.Substitute("uid={username},cn=users,dc=example,dc=com")
-//
-// returns "uid=john,cn=users,dc=example,dc=com"
-//
-// whereas:
-//
-// subber.Substitute("uid=${usernamedn}")
-//
-// returns an error.
-func (s *Substituter) Substitute(t string) (string, error) {
-	for k, v := range s.vals {
-		reDollar := regexp.MustCompile(fmt.Sprintf(`\$\{%s\}`, k))
-		t = reDollar.ReplaceAllLiteralString(t, v)
-		reFlower := regexp.MustCompile(fmt.Sprintf(`\{%s\}`, k))
-		t = reFlower.ReplaceAllLiteralString(t, v)
-	}
-	// Check if all requested substitutions have been made.
-	re := regexp.MustCompile(`\{.*\}`)
-	if re.MatchString(t) {
-		return "", errors.New("unsupported substitution requested")
-	}
-	return t, nil
-}