vault: Adding enable/disable audit methods

vault/audit.go

@@ -4,6 +4,8 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"strings"
+	"sync"
 
 	"github.com/hashicorp/vault/audit"
 )
@@ -13,6 +15,10 @@ const (
 	// Audit configuration is protected within the Vault itself, which means it
 	// can only be viewed or modified after an unseal.
 	coreAuditConfigPath = "core/audit"
+
+	// auditBarrierPrefix is the prefix to the UUID used in the
+	// barrier view for the audit backends.
+	auditBarrierPrefix = "audit/"
 )
 
 var (
@@ -20,6 +26,86 @@ var (
 	loadAuditFailed = errors.New("failed to setup audit table")
 )
 
+// enableAudit is used to enable a new audit backend
+func (c *Core) enableAudit(entry *MountEntry) error {
+	c.audit.Lock()
+	defer c.audit.Unlock()
+
+	// Ensure there is a name
+	if entry.Path == "" {
+		return fmt.Errorf("backend path must be specified")
+	}
+	if strings.Contains(entry.Path, "/") {
+		return fmt.Errorf("backend path cannot have a forward slash")
+	}
+
+	// Look for matching name
+	for _, ent := range c.audit.Entries {
+		if ent.Path == entry.Path {
+			return fmt.Errorf("path already in use")
+		}
+	}
+
+	// Lookup the new backend
+	backend, err := c.newAuditBackend(entry.Type, entry.Options)
+	if err != nil {
+		return err
+	}
+
+	// Generate a new UUID and view
+	entry.UUID = generateUUID()
+	view := NewBarrierView(c.barrier, auditBarrierPrefix+entry.UUID+"/")
+
+	// Update the audit table
+	newTable := c.audit.Clone()
+	newTable.Entries = append(newTable.Entries, entry)
+	if err := c.persistAudit(newTable); err != nil {
+		return errors.New("failed to update audit table")
+	}
+	c.audit = newTable
+
+	// Register the backend
+	c.auditBroker.Register(entry.Path, backend, view)
+	c.logger.Printf("[INFO] core: enabled audit backend '%s' type: %s",
+		entry.Path, entry.Type)
+	return nil
+}
+
+// disableAudit is used to disable an existing audit backend
+func (c *Core) disableAudit(path string) error {
+	c.audit.Lock()
+	defer c.audit.Unlock()
+
+	// Remove the entry from the mount table
+	found := false
+	newTable := c.audit.Clone()
+	n := len(newTable.Entries)
+	for i := 0; i < n; i++ {
+		if newTable.Entries[i].Path == path {
+			newTable.Entries[i], newTable.Entries[n-1] = newTable.Entries[n-1], nil
+			newTable.Entries = newTable.Entries[:n-1]
+			found = true
+			break
+		}
+	}
+
+	// Ensure there was a match
+	if !found {
+		return fmt.Errorf("no matching backend")
+	}
+
+	// Update the audit table
+	if err := c.persistAudit(newTable); err != nil {
+		return errors.New("failed to update audit table")
+	}
+	c.audit = newTable
+
+	// Unmount the backend
+	c.auditBroker.Deregister(path)
+	c.logger.Printf("[INFO] core: disabled audit backend '%s'", path)
+	return nil
+}
+
 // loadAudits is invoked as part of postUnseal to load the audit table
 func (c *Core) loadAudits() error {
 	// Load the existing audit table
@@ -75,7 +161,7 @@ func (c *Core) persistAudit(table *MountTable) error {
 // setupAudit is invoked after we've loaded the audit able to
 // initialize the audit backends
 func (c *Core) setupAudits() error {
-	var backends []audit.Backend
+	broker := NewAuditBroker()
 	for _, entry := range c.audit.Entries {
 		// Initialize the backend
 		audit, err := c.newAuditBackend(entry.Type, entry.Options)
@@ -86,12 +172,13 @@ func (c *Core) setupAudits() error {
 			return loadAuditFailed
 		}
 
-		// Append to the audit entry to the list of backends
-		backends = append(backends, audit)
-	}
+		// Create a barrier view using the UUID
+		view := NewBarrierView(c.barrier, auditBarrierPrefix+entry.UUID+"/")
 
-	// Setup the audit broker
-	c.auditBroker = NewAuditBroker(backends)
+		// Mount the backend
+		broker.Register(entry.Path, audit, view)
+	}
+	c.auditBroker = broker
 	return nil
 }
 
@@ -118,16 +205,47 @@ func defaultAuditTable() *MountTable {
 	return table
 }
 
+type backendEntry struct {
+	backend audit.Backend
+	view    *BarrierView
+}
+
 // AuditBroker is used to provide a single ingest interface to auditable
 // events given that multiple backends may be configured.
 type AuditBroker struct {
-	backends []audit.Backend
+	l        sync.RWMutex
+	backends map[string]backendEntry
 }
 
-// NewAuditBroker creates a new broker given the list of backends
-func NewAuditBroker(backends []audit.Backend) *AuditBroker {
+// NewAuditBroker creates a new audit broker
+func NewAuditBroker() *AuditBroker {
 	b := &AuditBroker{
-		backends: backends,
+		backends: make(map[string]backendEntry),
 	}
 	return b
 }
+
+// Register is used to add new audit backend to the broker
+func (a *AuditBroker) Register(name string, b audit.Backend, v *BarrierView) {
+	a.l.Lock()
+	defer a.l.Unlock()
+	a.backends[name] = backendEntry{
+		backend: b,
+		view:    v,
+	}
+}
+
+// Deregister is used to remove an audit backend from the broker
+func (a *AuditBroker) Deregister(name string) {
+	a.l.Lock()
+	defer a.l.Unlock()
+	delete(a.backends, name)
+}
+
+// IsRegistered is used to check if a given audit backend is registered
+func (a *AuditBroker) IsRegistered(name string) bool {
+	a.l.RLock()
+	defer a.l.RUnlock()
+	_, ok := a.backends[name]
+	return ok
+}

vault/audit_test.go

@@ -3,8 +3,110 @@ package vault
 import (
 	"reflect"
 	"testing"
+
+	"github.com/hashicorp/vault/audit"
 )
 
+type NoopAudit struct{}
+
+func TestCore_EnableAudit(t *testing.T) {
+	c, key, _ := TestCoreUnsealed(t)
+	c.auditBackends["noop"] = func(map[string]string) (audit.Backend, error) {
+		return &NoopAudit{}, nil
+	}
+
+	me := &MountEntry{
+		Path: "foo",
+		Type: "noop",
+	}
+	err := c.enableAudit(me)
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+
+	if !c.auditBroker.IsRegistered("foo") {
+		t.Fatalf("missing audit backend")
+	}
+
+	conf := &CoreConfig{
+		Physical:      c.physical,
+		AuditBackends: make(map[string]audit.Factory),
+	}
+	conf.AuditBackends["noop"] = func(map[string]string) (audit.Backend, error) {
+		return &NoopAudit{}, nil
+	}
+	c2, err := NewCore(conf)
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	unseal, err := c2.Unseal(key)
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	if !unseal {
+		t.Fatalf("should be unsealed")
+	}
+
+	// Verify matching audit tables
+	if !reflect.DeepEqual(c.audit, c2.audit) {
+		t.Fatalf("mismatch: %v %v", c.audit, c2.audit)
+	}
+
+	// Check for registration
+	if !c2.auditBroker.IsRegistered("foo") {
+		t.Fatalf("missing audit backend")
+	}
+}
+
+func TestCore_DisableAudit(t *testing.T) {
+	c, key, _ := TestCoreUnsealed(t)
+	c.auditBackends["noop"] = func(map[string]string) (audit.Backend, error) {
+		return &NoopAudit{}, nil
+	}
+
+	err := c.disableAudit("foo")
+	if err.Error() != "no matching backend" {
+		t.Fatalf("err: %v", err)
+	}
+
+	me := &MountEntry{
+		Path: "foo",
+		Type: "noop",
+	}
+	err = c.enableAudit(me)
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+
+	err = c.disableAudit("foo")
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+
+	// Check for registration
+	if c.auditBroker.IsRegistered("foo") {
+		t.Fatalf("audit backend present")
+	}
+
+	conf := &CoreConfig{Physical: c.physical}
+	c2, err := NewCore(conf)
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	unseal, err := c2.Unseal(key)
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	if !unseal {
+		t.Fatalf("should be unsealed")
+	}
+
+	// Verify matching mount tables
+	if !reflect.DeepEqual(c.audit, c2.audit) {
+		t.Fatalf("mismatch: %v %v", c.audit, c2.audit)
+	}
+}
+
 func TestCore_DefaultAuditTable(t *testing.T) {
 	c, key, _ := TestCoreUnsealed(t)
 	verifyDefaultAuditTable(t, c.audit)