Significantly enhanced LDAP support in Gogs.

3 files changed, 125 insertions, 101 deletions

diff --git a/modules/auth/ldap/README.md b/modules/auth/ldap/README.md
index 531ba85361..5d515848e2 100644
--- a/modules/auth/ldap/README.md
+++ b/modules/auth/ldap/README.md
@@ -1,43 +1,64 @@
-LDAP authentication
-===================
+Gogs LDAP Authentication Module
+===============================
 
-## Goal
+## About
 
-Authenticat user against LDAP directories
+This authentication module attempts to authorize and authenticate a user
+against an LDAP server. Like most LDAP authentication systems, this module does
+this in two steps. First, it queries the LDAP server using a Bind DN and
+searches for the user that is attempting to sign in. If the user is found, the
+module attempts to bind to the server using the user's supplied credentials. If
+this succeeds, the user has been authenticated, and his account information is
+retrieved and passed to the Gogs login infrastructure.
 
-It will bind with the user's login/pasword and query attributs ("mail" for instance) in a pool of directory servers
+## Usage
 
-The first OK wins.
+To use this module, add an LDAP authentication source via the Authentications
+section in the admin panel. The fields should be set as follows:
 
-If there's connection error, the server will be disabled and won't be checked again
+Authorization Name (required)
+	A name to assign to the new method of authorization.
 
-## Usage
+Host (required)
+	The address where the LDAP server can be reached.
+	Example: mydomain.com
+
+Port (required)
+	The port to use when connecting to the server.
+	Example: 636
 
-In the [security] section, set
->  LDAP_AUTH = true
+Enable TLS Encryption (optional)
+	Whether to use TLS when connecting to the LDAP server.
 
-then for each LDAP source, set
+Bind DN (optional)
+	The DN to bind to the LDAP server with when searching for the user.
+	This may be left blank to perform an anonymous search.
+	Example: cn=Search,dc=mydomain,dc=com
 
-> [LdapSource-someuniquename]
-> name=canonicalName
-> host=hostname-or-ip
-> port=3268	# or regular LDAP port
-> # the following settings depend highly how you've configured your AD
-> basedn=dc=ACME,dc=COM
-> MSADSAFORMAT=%s@ACME.COM
-> filter=(&(objectClass=user)(sAMAccountName=%s))
+Bind Password (optional)
+	The password for the Bind DN specified above, if any.
 
-### Limitation
+User Search Base (required)
+	The LDAP base at which user accounts will be searched for.
+	Example: ou=Users,dc=mydomain,dc=com
 
-Only tested on an MS 2008R2 DC, using global catalog (TCP/3268)
+User Filter (required)
+	An LDAP filter declaring how to find the user record that is attempting
+	to authenticate. The '%s' matching parameter will be substituted with
+	the user's username.
+	Example: (&(objectClass=posixAccount)(uid=%s))
 
-This MSAD is a mess.
+First name attribute (optional)
+	The attribute of the user's LDAP record containing the user's first
+	name. This will be used to populate their account information.
+	Example: givenName
 
-The way how one checks the directory (CN, DN etc...) may be highly depending local custom configuration
+Surname name attribute (optional)
+	The attribute of the user's LDAP record containing the user's surname
+	This will be used to populate their account information.
+	Example: sn
 
-### Todo
-* Define a timeout per server
-* Check servers marked as "Disabled" when they'll come back online
-* Find a more flexible way to define filter/MSADSAFORMAT/Attributes etc... maybe text/template ?
-* Check OpenLDAP server
-* SSL support ?
\ No newline at end of file
+E-mail attribute (required)
+	The attribute of the user's LDAP record containing the user's email
+	address. This will be used to populate their account information.
+	Example: mail
diff --git a/modules/auth/ldap/ldap.go b/modules/auth/ldap/ldap.go
index c78e241d37..f75d906e1d 100644
--- a/modules/auth/ldap/ldap.go
+++ b/modules/auth/ldap/ldap.go
@@ -19,82 +19,114 @@ type Ldapsource struct {
 	Host              string // LDAP host
 	Port              int    // port number
 	UseSSL            bool   // Use SSL
-	BaseDN            string // Base DN
-	AttributeUsername string // Username attribute
+	BindDN            string // DN to bind with
+	BindPassword      string // Bind DN password
+	UserBase          string // Base search path for users
 	AttributeName     string // First name attribute
 	AttributeSurname  string // Surname attribute
 	AttributeMail     string // E-mail attribute
 	Filter            string // Query filter to validate entry
-	MsAdSAFormat      string // in the case of MS AD Simple Authen, the format to use (see: http://msdn.microsoft.com/en-us/library/cc223499.aspx)
 	Enabled           bool   // if this source is disabled
 }
 
-//Global LDAP directory pool
-var (
-	Authensource []Ldapsource
-)
-
-// Add a new source (LDAP directory) to the global pool
-func AddSource(name string, host string, port int, usessl bool, basedn string, attribcn string, attribname string, attribsn string, attribmail string, filter string, msadsaformat string) {
-	ldaphost := Ldapsource{name, host, port, usessl, basedn, attribcn, attribname, attribsn, attribmail, filter, msadsaformat, true}
-	Authensource = append(Authensource, ldaphost)
-}
+func (ls Ldapsource) FindUserDN(name string) (userDN string, success bool) {
+	userDN = ""
+	success = false
+	l, err := ldapDial(ls)
+	if err != nil {
+		log.Error(4, "LDAP Connect error, %s:%v", ls.Host, err)
+		ls.Enabled = false
+		return
+	}
 
-//LoginUser : try to login an user to LDAP sources, return requested (attribute,true) if ok, ("",false) other wise
-//First match wins
-//Returns first attribute if exists
-func LoginUser(name, passwd string) (cn, fn, sn, mail string, r bool) {
-	r = false
-	for _, ls := range Authensource {
-		cn, fn, sn, mail, r = ls.SearchEntry(name, passwd)
-		if r {
+	defer l.Close()
+	log.Trace("Search for LDAP user: %s", name)
+	if ls.BindDN != "" && ls.BindPassword != "" {
+		err = l.Bind(ls.BindDN, ls.BindPassword)
+		if err != nil {
+			log.Debug("Failed to bind as BindDN: %s, %s", ls.BindDN, err.Error())
 			return
 		}
+		log.Trace("Bound as BindDN %s", ls.BindDN)
+	} else {
+		log.Trace("Proceeding with anonymous LDAP search.")
+	}
+
+	// A search for the user.
+	userFilter := fmt.Sprintf(ls.Filter, name)
+	log.Trace("Searching using filter %s", userFilter)
+	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.Debug("Failed search using filter %s: %s", userFilter, err.Error())
+		return
+	} else if len(sr.Entries) > 1 {
+		log.Debug("Filter '%s' returned more than one user.", userFilter)
+		return
 	}
+
+	userDN = sr.Entries[0].DN
+	if userDN == "" {
+		log.Error(4, "LDAP search was succesful, but found no DN!")
+		return
+	}
+
+	success = true
 	return
 }
 
-// searchEntry : search an LDAP source if an entry (name, passwd) is valide and in the specific filter
-func (ls Ldapsource) SearchEntry(name, passwd string) (string, string, string, string, bool) {
+// searchEntry : search an LDAP source if an entry (name, passwd) is valid and in the specific filter
+func (ls Ldapsource) SearchEntry(name, passwd string) (string, string, string, bool) {
+	userDN, found := ls.FindUserDN(name)
+	if !found {
+		return "", "", "", false
+	}
+
 	l, err := ldapDial(ls)
 	if err != nil {
 		log.Error(4, "LDAP Connect error, %s:%v", ls.Host, err)
 		ls.Enabled = false
-		return "", "", "", "", false
+		return "", "", "", false
 	}
+
 	defer l.Close()
 
-	nx := fmt.Sprintf(ls.MsAdSAFormat, name)
-	err = l.Bind(nx, passwd)
+	log.Trace("Binding with userDN: %s", userDN)
+	err = l.Bind(userDN, passwd)
 	if err != nil {
-		log.Debug("LDAP Authan failed for %s, reason: %s", nx, err.Error())
-		return "", "", "", "", false
+		log.Debug("LDAP auth. failed for %s, reason: %s", userDN, err.Error())
+		return "", "", "", false
 	}
 
+	log.Trace("Bound successfully with userDN: %s", userDN)
+	userFilter := fmt.Sprintf(ls.Filter, name)
 	search := ldap.NewSearchRequest(
-		ls.BaseDN,
-		ldap.ScopeWholeSubtree, ldap.NeverDerefAliases, 0, 0, false,
-		fmt.Sprintf(ls.Filter, name),
-		[]string{ls.AttributeUsername, ls.AttributeName, ls.AttributeSurname, ls.AttributeMail},
+		userDN, ldap.ScopeWholeSubtree, ldap.NeverDerefAliases, 0, 0, false, userFilter,
+		[]string{ls.AttributeName, ls.AttributeSurname, ls.AttributeMail},
 		nil)
+
 	sr, err := l.Search(search)
 	if err != nil {
-		log.Debug("LDAP Authen OK but not in filter %s", name)
-		return "", "", "", "", false
-	}
-	log.Debug("LDAP Authen OK: %s", name)
-	if len(sr.Entries) > 0 {
-		cn := sr.Entries[0].GetAttributeValue(ls.AttributeUsername)
-		name := sr.Entries[0].GetAttributeValue(ls.AttributeName)
-		sn := sr.Entries[0].GetAttributeValue(ls.AttributeSurname)
-		mail := sr.Entries[0].GetAttributeValue(ls.AttributeMail)
-		return cn, name, sn, mail, true
+		log.Error(4, "LDAP Search failed unexpectedly! (%s)", err.Error())
+		return "", "", "", false
+	} else if len(sr.Entries) < 1 {
+		log.Error(4, "LDAP Search failed unexpectedly! (0 entries)")
+		return "", "", "", false
 	}
-	return "", "", "", "", true
+
+	name_attr := sr.Entries[0].GetAttributeValue(ls.AttributeName)
+	sn_attr := sr.Entries[0].GetAttributeValue(ls.AttributeSurname)
+	mail_attr := sr.Entries[0].GetAttributeValue(ls.AttributeMail)
+	return name_attr, sn_attr, mail_attr, true
 }
 
 func ldapDial(ls Ldapsource) (*ldap.Conn, error) {
 	if ls.UseSSL {
+		log.Debug("Using TLS for LDAP")
 		return ldap.DialTLS("tcp", fmt.Sprintf("%s:%d", ls.Host, ls.Port), nil)
 	} else {
 		return ldap.Dial("tcp", fmt.Sprintf("%s:%d", ls.Host, ls.Port))
diff --git a/modules/auth/ldap/ldap_test.go b/modules/auth/ldap/ldap_test.go
deleted file mode 100644
index a842eebf9b..0000000000
--- a/modules/auth/ldap/ldap_test.go
+++ /dev/null
@@ -1,29 +0,0 @@
-package ldap
-
-// import (
-// 	"fmt"
-// 	"testing"
-// )
-
-// var ldapServer = "ldap.itd.umich.edu"
-// var ldapPort = 389
-// var baseDN = "dc=umich,dc=edu"
-// var filter = []string{
-// 	"(cn=cis-fac)",
-// 	"(&(objectclass=rfc822mailgroup)(cn=*Computer*))",
-// 	"(&(objectclass=rfc822mailgroup)(cn=*Mathematics*))"}
-// var attributes = []string{
-// 	"cn",
-// 	"description"}
-// var msadsaformat = ""
-
-// func TestLDAP(t *testing.T) {
-// 	AddSource("test", ldapServer, ldapPort, baseDN, attributes, filter, msadsaformat)
-// 	user, err := LoginUserLdap("xiaolunwen", "")
-// 	if err != nil {
-// 		t.Error(err)
-// 		return
-// 	}
-
-// 	fmt.Println(user)
-// }