Merge pull request #725 from nats-io/deny

Deny/Allow Permissions

server/auth.go

@@ -56,19 +56,43 @@ func (u *User) clone() *User {
 	return clone
 }
 
+// SubjectPermission is an individual allow and deny struct for publish
+// and subscribe authorizations.
+type SubjectPermission struct {
+	Allow []string `json:"allow"`
+	Deny  []string `json:"deny"`
+}
+
 // Permissions are the allowed subjects on a per
 // publish or subscribe basis.
 type Permissions struct {
-	Publish   []string `json:"publish"`
-	Subscribe []string `json:"subscribe"`
+	Publish   *SubjectPermission `json:"publish"`
+	Subscribe *SubjectPermission `json:"subscribe"`
 }
 
 // RoutePermissions are similar to user permissions
 // but describe what a server can import/export from and to
 // another server.
 type RoutePermissions struct {
-	Import []string `json:"import"`
-	Export []string `json:"export"`
+	Import *SubjectPermission `json:"import"`
+	Export *SubjectPermission `json:"export"`
+}
+
+// clone will clone an individual subject permission.
+func (p *SubjectPermission) clone() *SubjectPermission {
+	if p == nil {
+		return nil
+	}
+	clone := &SubjectPermission{}
+	if p.Allow != nil {
+		clone.Allow = make([]string, len(p.Allow))
+		copy(clone.Allow, p.Allow)
+	}
+	if p.Deny != nil {
+		clone.Deny = make([]string, len(p.Deny))
+		copy(clone.Deny, p.Deny)
+	}
+	return clone
 }
 
 // clone performs a deep copy of the Permissions struct, returning a new clone
@@ -79,12 +103,10 @@ func (p *Permissions) clone() *Permissions {
 	}
 	clone := &Permissions{}
 	if p.Publish != nil {
-		clone.Publish = make([]string, len(p.Publish))
-		copy(clone.Publish, p.Publish)
+		clone.Publish = p.Publish.clone()
 	}
 	if p.Subscribe != nil {
-		clone.Subscribe = make([]string, len(p.Subscribe))
-		copy(clone.Subscribe, p.Subscribe)
+		clone.Subscribe = p.Subscribe.clone()
 	}
 	return clone
 }

server/auth_test.go

@@ -42,8 +42,12 @@ func TestUserClone(t *testing.T) {
 		Username: "foo",
 		Password: "bar",
 		Permissions: &Permissions{
-			Publish:   []string{"foo"},
-			Subscribe: []string{"bar"},
+			Publish: &SubjectPermission{
+				Allow: []string{"foo"},
+			},
+			Subscribe: &SubjectPermission{
+				Allow: []string{"bar"},
+			},
 		},
 	}
 
@@ -54,7 +58,7 @@ func TestUserClone(t *testing.T) {
 			user, clone)
 	}
 
-	clone.Permissions.Subscribe = []string{"baz"}
+	clone.Permissions.Subscribe.Allow = []string{"baz"}
 	if reflect.DeepEqual(user, clone) {
 		t.Fatal("Expected Users to be different")
 	}

server/client.go

@@ -185,9 +185,13 @@ type outbound struct {
 	lft time.Duration // Last flush time.
 }
 
+type perm struct {
+	allow *Sublist
+	deny  *Sublist
+}
 type permissions struct {
-	sub    *Sublist
-	pub    *Sublist
+	sub    perm
+	pub    perm
 	pcache map[string]bool
 }
 
@@ -322,22 +326,39 @@ func (c *client) RegisterUser(user *User) {
 // Initializes client.perms structure.
 // Lock is held on entry.
 func (c *client) setPermissions(perms *Permissions) {
-	// Pre-allocate all to simplify checks later.
 	c.perms = &permissions{}
-	c.perms.sub = NewSublist()
-	c.perms.pub = NewSublist()
 	c.perms.pcache = make(map[string]bool)
 
 	// Loop over publish permissions
-	for _, pubSubject := range perms.Publish {
+	if len(perms.Publish.Allow) > 0 {
+		c.perms.pub.allow = NewSublist()
+	}
+	for _, pubSubject := range perms.Publish.Allow {
+		sub := &subscription{subject: []byte(pubSubject)}
+		c.perms.pub.allow.Insert(sub)
+	}
+	if len(perms.Publish.Deny) > 0 {
+		c.perms.pub.deny = NewSublist()
+	}
+	for _, pubSubject := range perms.Publish.Deny {
 		sub := &subscription{subject: []byte(pubSubject)}
-		c.perms.pub.Insert(sub)
+		c.perms.pub.deny.Insert(sub)
 	}
 
 	// Loop over subscribe permissions
-	for _, subSubject := range perms.Subscribe {
+	if len(perms.Subscribe.Allow) > 0 {
+		c.perms.sub.allow = NewSublist()
+	}
+	for _, subSubject := range perms.Subscribe.Allow {
 		sub := &subscription{subject: []byte(subSubject)}
-		c.perms.sub.Insert(sub)
+		c.perms.sub.allow.Insert(sub)
+	}
+	if len(perms.Subscribe.Deny) > 0 {
+		c.perms.sub.deny = NewSublist()
+	}
+	for _, subSubject := range perms.Subscribe.Deny {
+		sub := &subscription{subject: []byte(subSubject)}
+		c.perms.sub.deny.Insert(sub)
 	}
 }
 
@@ -1184,11 +1205,24 @@ func (c *client) processSub(argo []byte) (err error) {
 
 // canSubscribe determines if the client is authorized to subscribe to the
 // given subject. Assumes caller is holding lock.
-func (c *client) canSubscribe(sub []byte) bool {
+func (c *client) canSubscribe(subject []byte) bool {
 	if c.perms == nil {
 		return true
 	}
-	return len(c.perms.sub.Match(string(sub)).psubs) > 0
+
+	allowed := true
+
+	// Check allow list. If no allow list that means all are allowed. Deny can overrule.
+	if c.perms.sub.allow != nil {
+		r := c.perms.sub.allow.Match(string(subject))
+		allowed = len(r.psubs) != 0
+	}
+	// If we have a deny list and we think we are allowed, check that as well.
+	if allowed && c.perms.sub.deny != nil {
+		r := c.perms.sub.deny.Match(string(subject))
+		allowed = len(r.psubs) == 0
+	}
+	return allowed
 }
 
 // Low level unsubscribe for a given client.
@@ -1400,10 +1434,24 @@ func (c *client) pubAllowed(subject []byte) bool {
 	if ok {
 		return allowed
 	}
-	// Cache miss
-	r := c.perms.pub.Match(string(subject))
-	allowed = len(r.psubs) != 0
+
+	// Cache miss, check allow then deny as needed.
+	if c.perms.pub.allow != nil {
+		r := c.perms.pub.allow.Match(string(subject))
+		allowed = len(r.psubs) != 0
+	} else {
+		// No entries means all are allowed. Deny will overrule as needed.
+		allowed = true
+	}
+	// If we have a deny list and are currently allowed, check that as well.
+	if allowed && c.perms.pub.deny != nil {
+		r := c.perms.pub.deny.Match(string(subject))
+		allowed = len(r.psubs) == 0
+	}
+
+	// Update our cache here.
 	c.perms.pcache[string(subject)] = allowed
+
 	// Prune if needed.
 	if len(c.perms.pcache) > maxPermCacheSize {
 		c.prunePubPermsCache()

server/configs/new_style_authorization.conf

@@ -0,0 +1,33 @@
+listen: 127.0.0.1:4222
+
+authorization {
+  # Our new style role based permissions.
+  # These support both allow and deny.
+
+  # If allow is empty it means all or ">"
+  # If deny is empty it means none, or empty list.
+
+  normal_user = {
+    # Can send to foo, bar or baz only.
+    publish = {
+      allow = ["foo", "bar", "baz"]
+    }
+    # Can subscribe to everything but $SYSTEM prefixed subjects.
+    subscribe = {
+      deny = "$SYSTEM.>"
+    }
+  }
+
+ admin_user = {
+   publish = "$SYSTEM.>"
+   subscribe = {
+     deny = ["foo", "bar", "baz"]
+   }
+ }
+
+  # Users listed with persmissions.
+  users = [
+    {user: alice, password: foo, permissions: $normal_user}
+    {user: bob, password: special, permissions: $admin_user}
+  ]
+}

server/opts.go

@@ -395,8 +395,14 @@ func parseCluster(cm map[string]interface{}, opts *Options) error {
 				// The parsing sets Import into Publish and Export into Subscribe, convert
 				// accordingly.
 				opts.Cluster.Permissions = &RoutePermissions{
-					Import: auth.defaultPermissions.Publish,
-					Export: auth.defaultPermissions.Subscribe,
+					Import: &SubjectPermission{
+						Allow: auth.defaultPermissions.Publish.Allow,
+						Deny:  auth.defaultPermissions.Publish.Deny,
+					},
+					Export: &SubjectPermission{
+						Allow: auth.defaultPermissions.Subscribe.Allow,
+						Deny:  auth.defaultPermissions.Subscribe.Deny,
+					},
 				}
 			}
 		case "routes":
@@ -538,24 +544,36 @@ func parseUserPermissions(pm map[string]interface{}) (*Permissions, error) {
 		// Import is Publish
 		// Export is Subscribe
 		case "pub", "publish", "import":
-			subjects, err := parseSubjects(v)
+			perms, err := parseVariablePermissions(v)
 			if err != nil {
 				return nil, err
 			}
-			p.Publish = subjects
+			p.Publish = perms
 		case "sub", "subscribe", "export":
-			subjects, err := parseSubjects(v)
+			perms, err := parseVariablePermissions(v)
 			if err != nil {
 				return nil, err
 			}
-			p.Subscribe = subjects
+			p.Subscribe = perms
 		default:
 			return nil, fmt.Errorf("Unknown field %s parsing permissions", k)
 		}
 	}
 	return p, nil
 }
 
+// Tope level parser for authorization configurations.
+func parseVariablePermissions(v interface{}) (*SubjectPermission, error) {
+	switch v.(type) {
+	case map[string]interface{}:
+		// New style with allow and/or deny properties.
+		return parseSubjectPermission(v.(map[string]interface{}))
+	default:
+		// Old style
+		return parseOldPermissionStyle(v)
+	}
+}
+
 // Helper function to parse subject singeltons and/or arrays
 func parseSubjects(v interface{}) ([]string, error) {
 	var subjects []string
@@ -575,17 +593,58 @@ func parseSubjects(v interface{}) ([]string, error) {
 	default:
 		return nil, fmt.Errorf("Expected subject permissions to be a subject, or array of subjects, got %T", v)
 	}
-	return checkSubjectArray(subjects)
+	if err := checkSubjectArray(subjects); err != nil {
+		return nil, err
+	}
+	return subjects, nil
+}
+
+// Helper function to parse old style authorization configs.
+func parseOldPermissionStyle(v interface{}) (*SubjectPermission, error) {
+	subjects, err := parseSubjects(v)
+	if err != nil {
+		return nil, err
+	}
+	return &SubjectPermission{Allow: subjects}, nil
+}
+
+// Helper function to parse new style authorization into a SubjectPermission with Allow and Deny.
+func parseSubjectPermission(m map[string]interface{}) (*SubjectPermission, error) {
+	if len(m) == 0 {
+		return nil, nil
+	}
+
+	p := &SubjectPermission{}
+
+	for k, v := range m {
+		switch strings.ToLower(k) {
+		case "allow":
+			subjects, err := parseSubjects(v)
+			if err != nil {
+				return nil, err
+			}
+			p.Allow = subjects
+		case "deny":
+			subjects, err := parseSubjects(v)
+			if err != nil {
+				return nil, err
+			}
+			p.Deny = subjects
+		default:
+			return nil, fmt.Errorf("Unknown field name %q parsing subject permissions, only 'allow' or 'deny' are permitted", k)
+		}
+	}
+	return p, nil
 }
 
 // Helper function to validate subjects, etc for account permissioning.
-func checkSubjectArray(sa []string) ([]string, error) {
+func checkSubjectArray(sa []string) error {
 	for _, s := range sa {
 		if !IsValidSubject(s) {
-			return nil, fmt.Errorf("Subject %q is not a valid subject", s)
+			return fmt.Errorf("Subject %q is not a valid subject", s)
 		}
 	}
-	return sa, nil
+	return nil
 }
 
 // PrintTLSHelpAndDie prints TLS usage and exits.