open-vault/helper/keysutil/lock_manager.go

505 lines
12 KiB
Go

package keysutil
import (
"context"
"encoding/base64"
"errors"
"fmt"
"sync"
"time"
"github.com/hashicorp/vault/helper/jsonutil"
"github.com/hashicorp/vault/logical"
)
const (
shared = false
exclusive = true
)
var (
errNeedExclusiveLock = errors.New("an exclusive lock is needed for this operation")
)
// PolicyRequest holds values used when requesting a policy. Most values are
// only used during an upsert.
type PolicyRequest struct {
// The storage to use
Storage logical.Storage
// The name of the policy
Name string
// The key type
KeyType KeyType
// Whether it should be derived
Derived bool
// Whether to enable convergent encryption
Convergent bool
// Whether to allow export
Exportable bool
// Whether to upsert
Upsert bool
// Whether to allow plaintext backup
AllowPlaintextBackup bool
}
type LockManager struct {
// A lock for each named key
locks map[string]*sync.RWMutex
// A mutex for the map itself
locksMutex sync.RWMutex
// If caching is enabled, the map of name to in-memory policy cache
cache map[string]*Policy
// Used for global locking, and as the cache map mutex
cacheMutex sync.RWMutex
}
func NewLockManager(cacheDisabled bool) *LockManager {
lm := &LockManager{
locks: map[string]*sync.RWMutex{},
}
if !cacheDisabled {
lm.cache = map[string]*Policy{}
}
return lm
}
func (lm *LockManager) CacheActive() bool {
return lm.cache != nil
}
func (lm *LockManager) InvalidatePolicy(name string) {
// Check if it's in our cache. If so, return right away.
if lm.CacheActive() {
lm.cacheMutex.Lock()
defer lm.cacheMutex.Unlock()
delete(lm.cache, name)
}
}
func (lm *LockManager) policyLock(name string, lockType bool) *sync.RWMutex {
lm.locksMutex.RLock()
lock := lm.locks[name]
if lock != nil {
// We want to give this up before locking the lock, but it's safe --
// the only time we ever write to a value in this map is the first time
// we access the value, so it won't be changing out from under us
lm.locksMutex.RUnlock()
if lockType == exclusive {
lock.Lock()
} else {
lock.RLock()
}
return lock
}
lm.locksMutex.RUnlock()
lm.locksMutex.Lock()
// Don't defer the unlock call because if we get a valid lock below we want
// to release the lock mutex right away to avoid the possibility of
// deadlock by trying to grab the second lock
// Check to make sure it hasn't been created since
lock = lm.locks[name]
if lock != nil {
lm.locksMutex.Unlock()
if lockType == exclusive {
lock.Lock()
} else {
lock.RLock()
}
return lock
}
lock = &sync.RWMutex{}
lm.locks[name] = lock
lm.locksMutex.Unlock()
if lockType == exclusive {
lock.Lock()
} else {
lock.RLock()
}
return lock
}
func (lm *LockManager) UnlockPolicy(lock *sync.RWMutex, lockType bool) {
if lockType == exclusive {
lock.Unlock()
} else {
lock.RUnlock()
}
}
func (lm *LockManager) UpdateCache(name string, policy *Policy) {
if lm.CacheActive() {
lm.cacheMutex.Lock()
defer lm.cacheMutex.Unlock()
lm.cache[name] = policy
}
}
// Get the policy with a read lock. If we get an error saying an exclusive lock
// is needed (for instance, for an upgrade/migration), give up the read lock,
// call again with an exclusive lock, then swap back out for a read lock.
func (lm *LockManager) GetPolicyShared(ctx context.Context, storage logical.Storage, name string) (*Policy, *sync.RWMutex, error) {
p, lock, _, err := lm.getPolicyCommon(ctx, PolicyRequest{
Storage: storage,
Name: name,
}, shared)
if err == nil ||
(err != nil && err != errNeedExclusiveLock) {
return p, lock, err
}
// Try again while asking for an exclusive lock
p, lock, _, err = lm.getPolicyCommon(ctx, PolicyRequest{
Storage: storage,
Name: name,
}, exclusive)
if err != nil || p == nil || lock == nil {
return p, lock, err
}
lock.Unlock()
p, lock, _, err = lm.getPolicyCommon(ctx, PolicyRequest{
Storage: storage,
Name: name,
}, shared)
return p, lock, err
}
// Get the policy with an exclusive lock
func (lm *LockManager) GetPolicyExclusive(ctx context.Context, storage logical.Storage, name string) (*Policy, *sync.RWMutex, error) {
p, lock, _, err := lm.getPolicyCommon(ctx, PolicyRequest{
Storage: storage,
Name: name,
}, exclusive)
return p, lock, err
}
// Get the policy with a read lock; if it returns that an exclusive lock is
// needed, retry. If successful, call one more time to get a read lock and
// return the value.
func (lm *LockManager) GetPolicyUpsert(ctx context.Context, req PolicyRequest) (*Policy, *sync.RWMutex, bool, error) {
req.Upsert = true
p, lock, _, err := lm.getPolicyCommon(ctx, req, shared)
if err == nil ||
(err != nil && err != errNeedExclusiveLock) {
return p, lock, false, err
}
// Try again while asking for an exclusive lock
p, lock, upserted, err := lm.getPolicyCommon(ctx, req, exclusive)
if err != nil || p == nil || lock == nil {
return p, lock, upserted, err
}
lock.Unlock()
req.Upsert = false
// Now get a shared lock for the return, but preserve the value of upserted
p, lock, _, err = lm.getPolicyCommon(ctx, req, shared)
return p, lock, upserted, err
}
// RestorePolicy acquires an exclusive lock on the policy name and restores the
// given policy along with the archive.
func (lm *LockManager) RestorePolicy(ctx context.Context, storage logical.Storage, name, backup string) error {
var p *Policy
var err error
backupBytes, err := base64.StdEncoding.DecodeString(backup)
if err != nil {
return err
}
var keyData KeyData
err = jsonutil.DecodeJSON(backupBytes, &keyData)
if err != nil {
return err
}
// Set a different name if desired
if name != "" {
keyData.Policy.Name = name
}
name = keyData.Policy.Name
// set the policy version cache
keyData.Policy.versionPrefixCache = &sync.Map{}
lockType := exclusive
lock := lm.policyLock(name, lockType)
defer lm.UnlockPolicy(lock, lockType)
// If the policy is in cache, error out
if lm.CacheActive() {
lm.cacheMutex.RLock()
p = lm.cache[name]
if p != nil {
lm.cacheMutex.RUnlock()
return fmt.Errorf(fmt.Sprintf("policy %q already exists", name))
}
lm.cacheMutex.RUnlock()
}
// If the policy exists in storage, error out
p, err = lm.getStoredPolicy(ctx, storage, name)
if err != nil {
return err
}
if p != nil {
return fmt.Errorf(fmt.Sprintf("policy %q already exists", name))
}
// Restore the archived keys
if keyData.ArchivedKeys != nil {
err = keyData.Policy.storeArchive(ctx, storage, keyData.ArchivedKeys)
if err != nil {
return fmt.Errorf("failed to restore archived keys for policy %q: %v", name, err)
}
}
// Mark that policy as a restored key
keyData.Policy.RestoreInfo = &RestoreInfo{
Time: time.Now(),
Version: keyData.Policy.LatestVersion,
}
// Restore the policy. This will also attempt to adjust the archive.
err = keyData.Policy.Persist(ctx, storage)
if err != nil {
return fmt.Errorf("failed to restore the policy %q: %v", name, err)
}
// Update the cache to contain the restored policy
lm.UpdateCache(name, keyData.Policy)
return nil
}
func (lm *LockManager) BackupPolicy(ctx context.Context, storage logical.Storage, name string) (string, error) {
p, lock, err := lm.GetPolicyExclusive(ctx, storage, name)
if lock != nil {
defer lock.Unlock()
}
if err != nil {
return "", err
}
if p == nil {
return "", fmt.Errorf("invalid key %q", name)
}
backup, err := p.Backup(ctx, storage)
if err != nil {
return "", err
}
// Update the cache since the policy would now have the backup information
lm.UpdateCache(name, p)
return backup, nil
}
// When the function returns, a lock will be held on the policy if err == nil.
// It is the caller's responsibility to unlock.
func (lm *LockManager) getPolicyCommon(ctx context.Context, req PolicyRequest, lockType bool) (*Policy, *sync.RWMutex, bool, error) {
lock := lm.policyLock(req.Name, lockType)
var p *Policy
var err error
// Check if it's in our cache. If so, return right away.
if lm.CacheActive() {
lm.cacheMutex.RLock()
p = lm.cache[req.Name]
if p != nil {
lm.cacheMutex.RUnlock()
return p, lock, false, nil
}
lm.cacheMutex.RUnlock()
}
// Load it from storage
p, err = lm.getStoredPolicy(ctx, req.Storage, req.Name)
if err != nil {
lm.UnlockPolicy(lock, lockType)
return nil, nil, false, err
}
if p == nil {
// This is the only place we upsert a new policy, so if upsert is not
// specified, or the lock type is wrong, unlock before returning
if !req.Upsert {
lm.UnlockPolicy(lock, lockType)
return nil, nil, false, nil
}
if lockType != exclusive {
lm.UnlockPolicy(lock, lockType)
return nil, nil, false, errNeedExclusiveLock
}
switch req.KeyType {
case KeyType_AES256_GCM96, KeyType_ChaCha20_Poly1305:
if req.Convergent && !req.Derived {
lm.UnlockPolicy(lock, lockType)
return nil, nil, false, fmt.Errorf("convergent encryption requires derivation to be enabled")
}
case KeyType_ECDSA_P256:
if req.Derived || req.Convergent {
lm.UnlockPolicy(lock, lockType)
return nil, nil, false, fmt.Errorf("key derivation and convergent encryption not supported for keys of type %v", req.KeyType)
}
case KeyType_ED25519:
if req.Convergent {
lm.UnlockPolicy(lock, lockType)
return nil, nil, false, fmt.Errorf("convergent encryption not supported for keys of type %v", req.KeyType)
}
case KeyType_RSA2048, KeyType_RSA4096:
if req.Derived || req.Convergent {
lm.UnlockPolicy(lock, lockType)
return nil, nil, false, fmt.Errorf("key derivation and convergent encryption not supported for keys of type %v", req.KeyType)
}
default:
lm.UnlockPolicy(lock, lockType)
return nil, nil, false, fmt.Errorf("unsupported key type %v", req.KeyType)
}
p = &Policy{
Name: req.Name,
Type: req.KeyType,
Derived: req.Derived,
Exportable: req.Exportable,
AllowPlaintextBackup: req.AllowPlaintextBackup,
versionPrefixCache: &sync.Map{},
}
if req.Derived {
p.KDF = Kdf_hkdf_sha256
p.ConvergentEncryption = req.Convergent
p.ConvergentVersion = 2
}
err = p.Rotate(ctx, req.Storage)
if err != nil {
lm.UnlockPolicy(lock, lockType)
return nil, nil, false, err
}
if lm.CacheActive() {
// Since we didn't have the policy in the cache, if there was no
// error, write the value in.
lm.cacheMutex.Lock()
defer lm.cacheMutex.Unlock()
// Make sure a policy didn't appear. If so, it will only be set if
// there was no error, so assume it's good and return that
exp := lm.cache[req.Name]
if exp != nil {
return exp, lock, false, nil
}
if err == nil {
lm.cache[req.Name] = p
}
}
// We don't need to worry about upgrading since it will be a new policy
return p, lock, true, nil
}
if p.NeedsUpgrade() {
if lockType == shared {
lm.UnlockPolicy(lock, lockType)
return nil, nil, false, errNeedExclusiveLock
}
err = p.Upgrade(ctx, req.Storage)
if err != nil {
lm.UnlockPolicy(lock, lockType)
return nil, nil, false, err
}
}
if lm.CacheActive() {
// Since we didn't have the policy in the cache, if there was no
// error, write the value in.
lm.cacheMutex.Lock()
defer lm.cacheMutex.Unlock()
// Make sure a policy didn't appear. If so, it will only be set if
// there was no error, so assume it's good and return that
exp := lm.cache[req.Name]
if exp != nil {
return exp, lock, false, nil
}
if err == nil {
lm.cache[req.Name] = p
}
}
return p, lock, false, nil
}
func (lm *LockManager) DeletePolicy(ctx context.Context, storage logical.Storage, name string) error {
lm.cacheMutex.Lock()
lock := lm.policyLock(name, exclusive)
defer lock.Unlock()
defer lm.cacheMutex.Unlock()
var p *Policy
var err error
if lm.CacheActive() {
p = lm.cache[name]
}
if p == nil {
p, err = lm.getStoredPolicy(ctx, storage, name)
if err != nil {
return err
}
if p == nil {
return fmt.Errorf("could not delete policy; not found")
}
}
if !p.DeletionAllowed {
return fmt.Errorf("deletion is not allowed for this policy")
}
err = storage.Delete(ctx, "policy/"+name)
if err != nil {
return fmt.Errorf("error deleting policy %s: %s", name, err)
}
err = storage.Delete(ctx, "archive/"+name)
if err != nil {
return fmt.Errorf("error deleting archive %s: %s", name, err)
}
if lm.CacheActive() {
delete(lm.cache, name)
}
return nil
}
func (lm *LockManager) getStoredPolicy(ctx context.Context, storage logical.Storage, name string) (*Policy, error) {
return LoadPolicy(ctx, storage, "policy/"+name)
}