diff options
Diffstat (limited to 'internal/auth/ldap/ldap.go')
| -rw-r--r-- | internal/auth/ldap/ldap.go | 328 |
1 files changed, 328 insertions, 0 deletions
diff --git a/internal/auth/ldap/ldap.go b/internal/auth/ldap/ldap.go new file mode 100644 index 00000000..e88cef77 --- /dev/null +++ b/internal/auth/ldap/ldap.go @@ -0,0 +1,328 @@ +// Copyright 2014 The Gogs Authors. All rights reserved. +// Use of this source code is governed by a MIT-style +// license that can be found in the LICENSE file. + +// Package ldap provide functions & structure to query a LDAP ldap directory +// For now, it's mainly tested again an MS Active Directory service, see README.md for more information +package ldap + +import ( + "crypto/tls" + "fmt" + "strings" + + log "gopkg.in/clog.v1" + "gopkg.in/ldap.v2" +) + +type SecurityProtocol int + +// Note: new type must be added at the end of list to maintain compatibility. +const ( + SECURITY_PROTOCOL_UNENCRYPTED SecurityProtocol = iota + SECURITY_PROTOCOL_LDAPS + SECURITY_PROTOCOL_START_TLS +) + +// Basic LDAP authentication service +type Source struct { + Host string // LDAP host + Port int // port number + SecurityProtocol SecurityProtocol + SkipVerify bool + BindDN string `ini:"bind_dn,omitempty"` // DN to bind with + BindPassword string `ini:",omitempty"` // Bind DN password + UserBase string `ini:",omitempty"` // Base search path for users + UserDN string `ini:"user_dn,omitempty"` // Template for the DN of the user for simple auth + AttributeUsername string // Username attribute + AttributeName string // First name attribute + AttributeSurname string // Surname attribute + AttributeMail string // E-mail attribute + AttributesInBind bool // fetch attributes in bind context (not user) + Filter string // Query filter to validate entry + AdminFilter string // Query filter to check if user is admin + GroupEnabled bool // if the group checking is enabled + GroupDN string `ini:"group_dn"` // Group Search Base + GroupFilter string // Group Name Filter + GroupMemberUID string `ini:"group_member_uid"` // Group Attribute containing array of UserUID + UserUID string `ini:"user_uid"` // User Attribute listed in Group +} + +func (ls *Source) sanitizedUserQuery(username string) (string, bool) { + // See http://tools.ietf.org/search/rfc4515 + badCharacters := "\x00()*\\" + if strings.ContainsAny(username, badCharacters) { + log.Trace("LDAP: Username contains invalid query characters: %s", username) + return "", false + } + + return strings.Replace(ls.Filter, "%s", username, -1), true +} + +func (ls *Source) sanitizedUserDN(username string) (string, bool) { + // See http://tools.ietf.org/search/rfc4514: "special characters" + badCharacters := "\x00()*\\,='\"#+;<>" + if strings.ContainsAny(username, badCharacters) || strings.HasPrefix(username, " ") || strings.HasSuffix(username, " ") { + log.Trace("LDAP: Username contains invalid query characters: %s", username) + return "", false + } + + return strings.Replace(ls.UserDN, "%s", username, -1), true +} + +func (ls *Source) sanitizedGroupFilter(group string) (string, bool) { + // See http://tools.ietf.org/search/rfc4515 + badCharacters := "\x00*\\" + if strings.ContainsAny(group, badCharacters) { + log.Trace("LDAP: Group filter invalid query characters: %s", group) + return "", false + } + + return group, true +} + +func (ls *Source) sanitizedGroupDN(groupDn string) (string, bool) { + // See http://tools.ietf.org/search/rfc4514: "special characters" + badCharacters := "\x00()*\\'\"#+;<>" + if strings.ContainsAny(groupDn, badCharacters) || strings.HasPrefix(groupDn, " ") || strings.HasSuffix(groupDn, " ") { + log.Trace("LDAP: Group DN contains invalid query characters: %s", groupDn) + return "", false + } + + return groupDn, true +} + +func (ls *Source) findUserDN(l *ldap.Conn, name string) (string, bool) { + log.Trace("Search for LDAP user: %s", name) + if len(ls.BindDN) > 0 && len(ls.BindPassword) > 0 { + // Replace placeholders with username + bindDN := strings.Replace(ls.BindDN, "%s", name, -1) + err := l.Bind(bindDN, ls.BindPassword) + if err != nil { + log.Trace("LDAP: Failed to bind as BindDN '%s': %v", bindDN, err) + return "", false + } + log.Trace("LDAP: Bound as BindDN: %s", bindDN) + } else { + log.Trace("LDAP: Proceeding with anonymous LDAP search") + } + + // A search for the user. + userFilter, ok := ls.sanitizedUserQuery(name) + if !ok { + return "", false + } + + log.Trace("LDAP: Searching for DN using filter '%s' and base '%s'", userFilter, ls.UserBase) + search := ldap.NewSearchRequest( + ls.UserBase, ldap.ScopeWholeSubtree, ldap.NeverDerefAliases, 0, 0, + false, userFilter, []string{}, nil) + + // Ensure we found a user + sr, err := l.Search(search) + if err != nil || len(sr.Entries) < 1 { + log.Trace("LDAP: Failed search using filter '%s': %v", userFilter, err) + return "", false + } else if len(sr.Entries) > 1 { + log.Trace("LDAP: Filter '%s' returned more than one user", userFilter) + return "", false + } + + userDN := sr.Entries[0].DN + if userDN == "" { + log.Error(2, "LDAP: Search was successful, but found no DN!") + return "", false + } + + return userDN, true +} + +func dial(ls *Source) (*ldap.Conn, error) { + log.Trace("LDAP: Dialing with security protocol '%v' without verifying: %v", ls.SecurityProtocol, ls.SkipVerify) + + tlsCfg := &tls.Config{ + ServerName: ls.Host, + InsecureSkipVerify: ls.SkipVerify, + } + if ls.SecurityProtocol == SECURITY_PROTOCOL_LDAPS { + return ldap.DialTLS("tcp", fmt.Sprintf("%s:%d", ls.Host, ls.Port), tlsCfg) + } + + conn, err := ldap.Dial("tcp", fmt.Sprintf("%s:%d", ls.Host, ls.Port)) + if err != nil { + return nil, fmt.Errorf("Dial: %v", err) + } + + if ls.SecurityProtocol == SECURITY_PROTOCOL_START_TLS { + if err = conn.StartTLS(tlsCfg); err != nil { + conn.Close() + return nil, fmt.Errorf("StartTLS: %v", err) + } + } + + return conn, nil +} + +func bindUser(l *ldap.Conn, userDN, passwd string) error { + log.Trace("Binding with userDN: %s", userDN) + err := l.Bind(userDN, passwd) + if err != nil { + log.Trace("LDAP authentication failed for '%s': %v", userDN, err) + return err + } + log.Trace("Bound successfully with userDN: %s", userDN) + return err +} + +// searchEntry : search an LDAP source if an entry (name, passwd) is valid and in the specific filter +func (ls *Source) SearchEntry(name, passwd string, directBind bool) (string, string, string, string, bool, bool) { + // See https://tools.ietf.org/search/rfc4513#section-5.1.2 + if len(passwd) == 0 { + log.Trace("authentication failed for '%s' with empty password", name) + return "", "", "", "", false, false + } + l, err := dial(ls) + if err != nil { + log.Error(2, "LDAP connect failed for '%s': %v", ls.Host, err) + return "", "", "", "", false, false + } + defer l.Close() + + var userDN string + if directBind { + log.Trace("LDAP will bind directly via UserDN template: %s", ls.UserDN) + + var ok bool + userDN, ok = ls.sanitizedUserDN(name) + if !ok { + return "", "", "", "", false, false + } + } else { + log.Trace("LDAP will use BindDN") + + var found bool + userDN, found = ls.findUserDN(l, name) + if !found { + return "", "", "", "", false, false + } + } + + if directBind || !ls.AttributesInBind { + // binds user (checking password) before looking-up attributes in user context + err = bindUser(l, userDN, passwd) + if err != nil { + return "", "", "", "", false, false + } + } + + userFilter, ok := ls.sanitizedUserQuery(name) + if !ok { + return "", "", "", "", false, false + } + + log.Trace("Fetching attributes '%v', '%v', '%v', '%v', '%v' with filter '%s' and base '%s'", + ls.AttributeUsername, ls.AttributeName, ls.AttributeSurname, ls.AttributeMail, ls.UserUID, userFilter, userDN) + search := ldap.NewSearchRequest( + userDN, ldap.ScopeWholeSubtree, ldap.NeverDerefAliases, 0, 0, false, userFilter, + []string{ls.AttributeUsername, ls.AttributeName, ls.AttributeSurname, ls.AttributeMail, ls.UserUID}, + nil) + + sr, err := l.Search(search) + if err != nil { + log.Error(2, "LDAP: User search failed: %v", err) + return "", "", "", "", false, false + } else if len(sr.Entries) < 1 { + if directBind { + log.Trace("LDAP: User filter inhibited user login") + } else { + log.Trace("LDAP: User search failed: 0 entries") + } + + return "", "", "", "", false, false + } + + username := sr.Entries[0].GetAttributeValue(ls.AttributeUsername) + firstname := sr.Entries[0].GetAttributeValue(ls.AttributeName) + surname := sr.Entries[0].GetAttributeValue(ls.AttributeSurname) + mail := sr.Entries[0].GetAttributeValue(ls.AttributeMail) + uid := sr.Entries[0].GetAttributeValue(ls.UserUID) + + // Check group membership + if ls.GroupEnabled { + groupFilter, ok := ls.sanitizedGroupFilter(ls.GroupFilter) + if !ok { + return "", "", "", "", false, false + } + groupDN, ok := ls.sanitizedGroupDN(ls.GroupDN) + if !ok { + return "", "", "", "", false, false + } + + log.Trace("LDAP: Fetching groups '%v' with filter '%s' and base '%s'", ls.GroupMemberUID, groupFilter, groupDN) + groupSearch := ldap.NewSearchRequest( + groupDN, ldap.ScopeWholeSubtree, ldap.NeverDerefAliases, 0, 0, false, groupFilter, + []string{ls.GroupMemberUID}, + nil) + + srg, err := l.Search(groupSearch) + if err != nil { + log.Error(2, "LDAP: Group search failed: %v", err) + return "", "", "", "", false, false + } else if len(srg.Entries) < 1 { + log.Trace("LDAP: Group search returned no entries") + return "", "", "", "", false, false + } + + isMember := false + if ls.UserUID == "dn" { + for _, group := range srg.Entries { + for _, member := range group.GetAttributeValues(ls.GroupMemberUID) { + if member == sr.Entries[0].DN { + isMember = true + } + } + } + } else { + for _, group := range srg.Entries { + for _, member := range group.GetAttributeValues(ls.GroupMemberUID) { + if member == uid { + isMember = true + } + } + } + } + + if !isMember { + log.Trace("LDAP: Group membership test failed [username: %s, group_member_uid: %s, user_uid: %s", username, ls.GroupMemberUID, uid) + return "", "", "", "", false, false + } + } + + isAdmin := false + if len(ls.AdminFilter) > 0 { + log.Trace("Checking admin with filter '%s' and base '%s'", ls.AdminFilter, userDN) + search = ldap.NewSearchRequest( + userDN, ldap.ScopeWholeSubtree, ldap.NeverDerefAliases, 0, 0, false, ls.AdminFilter, + []string{ls.AttributeName}, + nil) + + sr, err = l.Search(search) + if err != nil { + log.Error(2, "LDAP: Admin search failed: %v", err) + } else if len(sr.Entries) < 1 { + log.Trace("LDAP: Admin search returned no entries") + } else { + isAdmin = true + } + } + + if !directBind && ls.AttributesInBind { + // binds user (checking password) after looking-up attributes in BindDN context + err = bindUser(l, userDN, passwd) + if err != nil { + return "", "", "", "", false, false + } + } + + return username, firstname, surname, mail, isAdmin, true +} |