Add 3.6+ user authenticationRestrictions (#229)

* Add 3.6 user authenticationRestrictions

* Add struct-field comment

* Add struct-field comment #2

* Add struct-field comment #3

* Add documentation link

* Fix comment

* Fix comment #2

* add to README.md

* add to README.md #2

* add to README.md #3

* Add positive/negative authentication restrictions user test

* Use denyUser for negative test

* Correct message

* Fix error match

* Fix close on nil/closed session

* Simplify test, last change :)

* Simplify test, last change :) #2

* Simplify test, last change :) #3

* Fix := error

Author: timvaillancourt

Diff for: README.md

@@ -58,7 +58,7 @@ A [sub-package](https://godoc.org/github.com/globalsign/mgo/bson) that implement
 * Support setting `writeConcern` for `findAndModify` operations ([details](https://github.com/globalsign/mgo/pull/185))
 * Add `ssl` to the dial string options ([details](https://github.com/globalsign/mgo/pull/184))
 * Support connecting via Unix sockets ([details](https://github.com/globalsign/mgo/pull/129))
-
+* Support MongoDB User authenticationRestrictions ([details](https://github.com/globalsign/mgo/pull/229))
 
 ---
 

Diff for: auth_test.go

@@ -341,6 +341,57 @@ func (s *S) TestAuthUpsertUserUpdates(c *C) {
 	c.Assert(err, IsNil)
 }
 
+func (s *S) TestAuthUpsertUserAuthenticationRestrictions(c *C) {
+	if !s.versionAtLeast(3, 6) {
+		c.Skip("UpsertUser with user 'authenticationRestrictions' only works on 3.6+")
+	}
+	session, err := mgo.Dial("localhost:40002")
+	c.Assert(err, IsNil)
+	defer session.Close()
+
+	admindb := session.DB("admin")
+	err = admindb.Login("root", "rapadura")
+
+	allowUser := &mgo.User{
+		Username: "authRestrictionUser",
+		Password: "123456",
+		Roles:    []mgo.Role{mgo.RoleReadWrite},
+		AuthenticationRestrictions: []mgo.AuthenticationRestriction{
+			{
+				ClientSource:  []string{"127.0.0.1"},
+				ServerAddress: []string{"127.0.0.1"},
+			},
+		},
+	}
+	err = admindb.UpsertUser(allowUser)
+	c.Assert(err, IsNil)
+
+	// Dial again to ensure the positive authentication restriction allows the connection
+	allowSession, err := mgo.Dial("mongodb://authRestrictionUser:[email protected]:40002/admin")
+	c.Assert(err, IsNil)
+	c.Assert(allowSession.Ping(), IsNil)
+	defer allowSession.Close()
+
+	// this user should fail authentication restrictions
+	denyUser := &mgo.User{
+		Username: "denyUser",
+		Password: "123456",
+		Roles:    []mgo.Role{mgo.RoleReadWrite},
+		AuthenticationRestrictions: []mgo.AuthenticationRestriction{
+			{
+				ClientSource:  []string{"1.2.3.4"},
+				ServerAddress: []string{"4.3.2.1"},
+			},
+		},
+	}
+	err = admindb.UpsertUser(denyUser)
+	c.Assert(err, IsNil)
+
+	// Dial again to ensure the authentication restriction blocks the connections.
+	_, err = mgo.Dial("mongodb://denyUser:[email protected]:40002/admin")
+	c.Assert(err, ErrorMatches, ".*Authentication failed.")
+}
+
 func (s *S) TestAuthAddUser(c *C) {
 	session, err := mgo.Dial("localhost:40002")
 	c.Assert(err, IsNil)

Diff for: session.go

@@ -1168,6 +1168,19 @@ func (s *Session) LogoutAll() {
 	s.m.Unlock()
 }
 
+// AuthenticationRestriction represents an authentication restriction
+// for a MongoDB User. Authentication Restrictions was added in version
+// 3.6.
+//
+// Relevant documentation:
+//
+//     https://docs.mongodb.com/manual/reference/method/db.createUser/#authentication-restrictions
+//
+type AuthenticationRestriction struct {
+	ClientSource  []string `bson:"clientSource,omitempty"`
+	ServerAddress []string `bson:"serverAddress,omitempty"`
+}
+
 // User represents a MongoDB user.
 //
 // Relevant documentation:
@@ -1208,6 +1221,15 @@ type User struct {
 	// WARNING: This setting was only ever supported in MongoDB 2.4,
 	// and is now obsolete.
 	UserSource string `bson:"userSource,omitempty"`
+
+	// AuthenticationRestrictions represents authentication restrictions
+	// the server enforces on the created user. Specifies a list of IP
+	// addresses and CIDR ranges from which the user is allowed to connect
+	// to the server or from which the server can accept users.
+	//
+	// WARNING: Authentication Restrictions are only supported in version
+	// 3.6 and above.
+	AuthenticationRestrictions []AuthenticationRestriction `bson:"authenticationRestrictions,omitempty"`
 }
 
 // Role available role for users
@@ -1370,6 +1392,9 @@ func (db *Database) runUserCmd(cmdName string, user *User) error {
 	if roles != nil || user.Roles != nil || cmdName == "createUser" {
 		cmd = append(cmd, bson.DocElem{Name: "roles", Value: roles})
 	}
+	if user.AuthenticationRestrictions != nil && len(user.AuthenticationRestrictions) > 0 {
+		cmd = append(cmd, bson.DocElem{Name: "authenticationRestrictions", Value: user.AuthenticationRestrictions})
+	}
 	err := db.Run(cmd, nil)
 	if !isNoCmd(err) && user.UserSource != "" && (user.UserSource != "$external" || db.Name != "$external") {
 		return fmt.Errorf("MongoDB 2.6+ does not support the UserSource setting")