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keyring: reduce locking and replication overhead
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While working on #23655 I found there were a few places in the encrypter/keyring
where we could make modest improvements to performance and reliability of the
existing code.

This changeset allows keyring replication to skip trying to replicate from
itself, switches some of the read-only keyring accesses to use the read lock
instead of a r/w lock, fixes the logging configuration to drop spurious "extra
value" warnings in the logs, drops an unused type, and makes a minor refactoring
to eliminate shadowing of the `keyset` type. Pulling this out to its own PR lets
us backport these changes to the LTS and reduces the size of the PR that
implements #23665.

Ref #23665
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@tgross
tgross committed Sep 17, 2024
1 parent 4d6856a commit 9e72dbc
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Showing 2 changed files with 39 additions and 45 deletions.
61 changes: 39 additions & 22 deletions nomad/encrypter.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -34,6 +34,7 @@ import (
"github.com/hashicorp/nomad/helper/joseutil"
"github.com/hashicorp/nomad/nomad/structs"
"github.com/hashicorp/nomad/nomad/structs/config"
"github.com/hashicorp/raft"
"golang.org/x/time/rate"
)

Expand Down Expand Up @@ -78,7 +79,7 @@ func NewEncrypter(srv *Server, keystorePath string) (*Encrypter, error) {

encrypter := &Encrypter{
srv: srv,
log: srv.logger.With("keyring"),
log: srv.logger.Named("keyring"),
keystorePath: keystorePath,
keyring: make(map[string]*keyset),
issuer: srv.GetConfig().OIDCIssuer,
Expand Down Expand Up @@ -218,16 +219,16 @@ func (e *Encrypter) Decrypt(ciphertext []byte, keyID string) ([]byte, error) {
e.lock.RLock()
defer e.lock.RUnlock()

keyset, err := e.keysetByIDLocked(keyID)
ks, err := e.keysetByIDLocked(keyID)
if err != nil {
return nil, err
}

nonceSize := keyset.cipher.NonceSize()
nonceSize := ks.cipher.NonceSize()
nonce := ciphertext[:nonceSize] // nonce was stored alongside ciphertext
additional := []byte(keyID) // keyID was included in the signature inputs

return keyset.cipher.Open(nil, nonce, ciphertext[nonceSize:], additional)
return ks.cipher.Open(nil, nonce, ciphertext[nonceSize:], additional)
}

// keyIDHeader is the JWT header for the Nomad Key ID used to sign the
Expand All @@ -249,7 +250,7 @@ func (e *Encrypter) SignClaims(claims *structs.IdentityClaims) (string, string,
// If a key is rotated immediately following a leader election, plans that
// are in-flight may get signed before the new leader has the key. Allow for
// a short timeout-and-retry to avoid rejecting plans
keyset, err := e.activeKeySet()
ks, err := e.activeKeySet()
if err != nil {
ctx, cancel := context.WithTimeout(e.srv.shutdownCtx, 5*time.Second)
defer cancel()
Expand All @@ -259,8 +260,8 @@ func (e *Encrypter) SignClaims(claims *structs.IdentityClaims) (string, string,
return "", "", err
default:
time.Sleep(50 * time.Millisecond)
keyset, err = e.activeKeySet()
if keyset != nil {
ks, err = e.activeKeySet()
if ks != nil {
break
}
}
Expand All @@ -272,18 +273,18 @@ func (e *Encrypter) SignClaims(claims *structs.IdentityClaims) (string, string,
claims.Issuer = e.issuer
}

opts := (&jose.SignerOptions{}).WithHeader("kid", keyset.rootKey.Meta.KeyID).WithType("JWT")
opts := (&jose.SignerOptions{}).WithHeader("kid", ks.rootKey.Meta.KeyID).WithType("JWT")

var sig jose.Signer
if keyset.rsaPrivateKey != nil {
if ks.rsaPrivateKey != nil {
// If an RSA key has been created prefer it as it is more widely compatible
sig, err = jose.NewSigner(jose.SigningKey{Algorithm: jose.RS256, Key: keyset.rsaPrivateKey}, opts)
sig, err = jose.NewSigner(jose.SigningKey{Algorithm: jose.RS256, Key: ks.rsaPrivateKey}, opts)
if err != nil {
return "", "", err
}
} else {
// No RSA key has been created, fallback to ed25519 which always exists
sig, err = jose.NewSigner(jose.SigningKey{Algorithm: jose.EdDSA, Key: keyset.eddsaPrivateKey}, opts)
sig, err = jose.NewSigner(jose.SigningKey{Algorithm: jose.EdDSA, Key: ks.eddsaPrivateKey}, opts)
if err != nil {
return "", "", err
}
Expand All @@ -294,7 +295,7 @@ func (e *Encrypter) SignClaims(claims *structs.IdentityClaims) (string, string,
return "", "", err
}

return raw, keyset.rootKey.Meta.KeyID, nil
return raw, ks.rootKey.Meta.KeyID, nil
}

// VerifyClaim accepts a previously-signed encoded claim and validates
Expand All @@ -312,7 +313,7 @@ func (e *Encrypter) VerifyClaim(tokenString string) (*structs.IdentityClaims, er
return nil, err
}

// Find the Key
// Find the key material
pubKey, err := e.GetPublicKey(keyID)
if err != nil {
return nil, err
Expand Down Expand Up @@ -594,8 +595,8 @@ var ErrDecryptFailed = errors.New("unable to decrypt wrapped key")
// GetPublicKey returns the public signing key for the requested key id or an
// error if the key could not be found.
func (e *Encrypter) GetPublicKey(keyID string) (*structs.KeyringPublicKey, error) {
e.lock.Lock()
defer e.lock.Unlock()
e.lock.RLock()
defer e.lock.RUnlock()

ks, err := e.keysetByIDLocked(keyID)
if err != nil {
Expand Down Expand Up @@ -746,6 +747,7 @@ func (krr *KeyringReplicator) replicateKey(ctx context.Context, keyMeta *structs
keyID := keyMeta.KeyID
krr.logger.Debug("replicating new key", "id", keyID)

var err error
getReq := &structs.KeyringGetRootKeyRequest{
KeyID: keyID,
QueryOptions: structs.QueryOptions{
Expand All @@ -754,7 +756,12 @@ func (krr *KeyringReplicator) replicateKey(ctx context.Context, keyMeta *structs
},
}
getResp := &structs.KeyringGetRootKeyResponse{}
err := krr.srv.RPC("Keyring.Get", getReq, getResp)

// Servers should avoid querying themselves
_, leaderID := krr.srv.raft.LeaderWithID()
if leaderID != raft.ServerID(krr.srv.GetConfig().NodeID) {
err = krr.srv.RPC("Keyring.Get", getReq, getResp)
}

if err != nil || getResp.Key == nil {
// Key replication needs to tolerate leadership flapping. If a key is
Expand All @@ -764,17 +771,28 @@ func (krr *KeyringReplicator) replicateKey(ctx context.Context, keyMeta *structs
krr.logger.Warn("failed to fetch key from current leader, trying peers",
"key", keyID, "error", err)
getReq.AllowStale = true

cfg := krr.srv.GetConfig()
self := fmt.Sprintf("%s.%s", cfg.NodeName, cfg.Region)

for _, peer := range krr.getAllPeers() {
if peer.Name == self {
continue
}

krr.logger.Trace("attempting to replicate key from peer",
"id", keyID, "peer", peer.Name)
err = krr.srv.forwardServer(peer, "Keyring.Get", getReq, getResp)
if err == nil && getResp.Key != nil {
break
}
}
if getResp.Key == nil {
krr.logger.Error("failed to fetch key from any peer",
"key", keyID, "error", err)
return fmt.Errorf("failed to fetch key from any peer: %v", err)
}
}

if getResp.Key == nil {
krr.logger.Error("failed to fetch key from any peer",
"key", keyID, "error", err)
return fmt.Errorf("failed to fetch key from any peer: %v", err)
}

err = krr.encrypter.AddKey(getResp.Key)
Expand All @@ -786,7 +804,6 @@ func (krr *KeyringReplicator) replicateKey(ctx context.Context, keyMeta *structs
return nil
}

// TODO: move this method into Server?
func (krr *KeyringReplicator) getAllPeers() []*serverParts {
krr.srv.peerLock.RLock()
defer krr.srv.peerLock.RUnlock()
Expand Down
23 changes: 0 additions & 23 deletions nomad/structs/keyring.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -196,17 +196,6 @@ func NewRootKeyMeta() *RootKeyMeta {
}
}

// RootKeyMetaStub is for serializing root key metadata to the
// keystore, not for the List API. It excludes frequently-changing
// fields such as ModifyIndex so we don't have to sync them to the
// on-disk keystore when the fields are already in raft.
type RootKeyMetaStub struct {
KeyID string
Algorithm EncryptionAlgorithm
CreateTime int64
State RootKeyState
}

// IsActive indicates this key is the one currently being used for crypto
// operations (at most one key can be Active)
func (rkm *RootKeyMeta) IsActive() bool {
Expand Down Expand Up @@ -270,18 +259,6 @@ func (rkm *RootKeyMeta) IsInactive() bool {
return rkm.State == RootKeyStateInactive || rkm.State == RootKeyStateDeprecated
}

func (rkm *RootKeyMeta) Stub() *RootKeyMetaStub {
if rkm == nil {
return nil
}
return &RootKeyMetaStub{
KeyID: rkm.KeyID,
Algorithm: rkm.Algorithm,
CreateTime: rkm.CreateTime,
State: rkm.State,
}

}
func (rkm *RootKeyMeta) Copy() *RootKeyMeta {
if rkm == nil {
return nil
Expand Down

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