Abstract generate-root authentication into the strategy interface (#7698)

* Abstract generate-root authentication into the strategy interface

* Generate root strategy ncabatoff (#7700)

* Adapt to new shamir-as-kek reality.

* Don't try to verify the master key when we might still be sealed (in
recovery mode).  Instead, verify it in the authenticate methods.

vault/core.go

@@ -2041,6 +2041,53 @@ func (c *Core) SetSealsForMigration(migrationSeal, newSeal, unwrapSeal Seal) {
 	}
 }
 
+// unsealKeyToMasterKey takes a key provided by the user, either a recovery key
+// if using an autoseal or an unseal key with Shamir.  It returns a nil error
+// if the key is valid and an error otherwise. It also returns the master key
+// that can be used to unseal the barrier.
+func (c *Core) unsealKeyToMasterKey(ctx context.Context, combinedKey []byte) ([]byte, error) {
+	switch c.seal.StoredKeysSupported() {
+	case StoredKeysSupportedGeneric:
+		if err := c.seal.VerifyRecoveryKey(ctx, combinedKey); err != nil {
+			return nil, errwrap.Wrapf("recovery key verification failed: {{err}}", err)
+		}
+
+		storedKeys, err := c.seal.GetStoredKeys(ctx)
+		if err == nil && len(storedKeys) != 1 {
+			err = fmt.Errorf("expected exactly one stored key, got %d", len(storedKeys))
+		}
+		if err != nil {
+			return nil, errwrap.Wrapf("unable to retrieve stored keys", err)
+		}
+		return storedKeys[0], nil
+
+	case StoredKeysSupportedShamirMaster:
+		testseal := NewDefaultSeal(shamirseal.NewSeal(c.logger.Named("testseal")))
+		testseal.SetCore(c)
+		cfg, err := c.seal.BarrierConfig(ctx)
+		if err != nil {
+			return nil, errwrap.Wrapf("failed to setup test barrier config: {{err}}", err)
+		}
+		testseal.SetCachedBarrierConfig(cfg)
+		err = testseal.GetAccess().(*shamirseal.ShamirSeal).SetKey(combinedKey)
+		if err != nil {
+			return nil, errwrap.Wrapf("failed to setup unseal key: {{err}}", err)
+		}
+		storedKeys, err := testseal.GetStoredKeys(ctx)
+		if err == nil && len(storedKeys) != 1 {
+			err = fmt.Errorf("expected exactly one stored key, got %d", len(storedKeys))
+		}
+		if err != nil {
+			return nil, errwrap.Wrapf("unable to retrieve stored keys", err)
+		}
+		return storedKeys[0], nil
+
+	case StoredKeysNotSupported:
+		return combinedKey, nil
+	}
+	return nil, fmt.Errorf("invalid seal")
+}
+
 func (c *Core) IsInSealMigration() bool {
 	c.stateLock.RLock()
 	defer c.stateLock.RUnlock()

vault/generate_root.go

@@ -13,7 +13,6 @@ import (
 	"github.com/hashicorp/vault/helper/xor"
 	"github.com/hashicorp/vault/sdk/helper/consts"
 	"github.com/hashicorp/vault/shamir"
-	shamirseal "github.com/hashicorp/vault/vault/seal/shamir"
 )
 
 const coreDROperationTokenPath = "core/dr-operation-token"
@@ -32,12 +31,25 @@ var (
 // create a token upon completion of the generate root process.
 type GenerateRootStrategy interface {
 	generate(context.Context, *Core) (string, func(), error)
+	authenticate(context.Context, *Core, []byte) error
 }
 
 // generateStandardRootToken implements the GenerateRootStrategy and is in
 // charge of creating standard root tokens.
 type generateStandardRootToken struct{}
 
+func (g generateStandardRootToken) authenticate(ctx context.Context, c *Core, combinedKey []byte) error {
+	_, err := c.unsealKeyToMasterKey(ctx, combinedKey)
+	if err != nil {
+		return errwrap.Wrapf("unable to authenticate: {{err}}", err)
+	}
+	if err := c.barrier.VerifyMaster(combinedKey); err != nil {
+		return errwrap.Wrapf("master key verification failed: {{err}}", err)
+	}
+
+	return nil
+}
+
 func (g generateStandardRootToken) generate(ctx context.Context, c *Core) (string, func(), error) {
 	te, err := c.tokenStore.rootToken(ctx)
 	if err != nil {
@@ -296,71 +308,9 @@ func (c *Core) GenerateRootUpdate(ctx context.Context, key []byte, nonce string,
 		}
 	}
 
-	switch {
-	case c.seal.RecoveryKeySupported():
-		// Ensure that the combined recovery key is valid
-		if err := c.seal.VerifyRecoveryKey(ctx, combinedKey); err != nil {
-			c.logger.Error("root generation aborted, recovery key verification failed", "error", err)
-			return nil, err
-		}
-		// If we are in recovery mode, then retrieve
-		// the stored keys and unseal the barrier
-		if c.recoveryMode {
-			storedKeys, err := c.seal.GetStoredKeys(ctx)
-			if err != nil {
-				return nil, errwrap.Wrapf("unable to retrieve stored keys in recovery mode: {{err}}", err)
-			}
-
-			// Use the retrieved master key to unseal the barrier
-			if err := c.barrier.Unseal(ctx, storedKeys[0]); err != nil {
-				c.logger.Error("root generation aborted, recovery operation token verification failed", "error", err)
-				return nil, err
-			}
-		}
-	default:
-		masterKey := combinedKey
-		if c.seal.StoredKeysSupported() == StoredKeysSupportedShamirMaster {
-			testseal := NewDefaultSeal(shamirseal.NewSeal(c.logger.Named("testseal")))
-			testseal.SetCore(c)
-			cfg, err := c.seal.BarrierConfig(ctx)
-			if err != nil {
-				return nil, errwrap.Wrapf("failed to setup test barrier config: {{err}}", err)
-			}
-			testseal.SetCachedBarrierConfig(cfg)
-			err = testseal.GetAccess().(*shamirseal.ShamirSeal).SetKey(combinedKey)
-			if err != nil {
-				return nil, errwrap.Wrapf("failed to setup unseal key: {{err}}", err)
-			}
-			stored, err := testseal.GetStoredKeys(ctx)
-			if err != nil {
-				return nil, errwrap.Wrapf("failed to read master key: {{err}}", err)
-			}
-			masterKey = stored[0]
-		}
-		switch {
-		case c.recoveryMode:
-			// If we are in recovery mode, being able to unseal
-			// the barrier is how we establish authentication
-			if err := c.barrier.Unseal(ctx, masterKey); err != nil {
-				c.logger.Error("root generation aborted, recovery operation token verification failed", "error", err)
-				return nil, err
-			}
-		default:
-			if err := c.barrier.VerifyMaster(masterKey); err != nil {
-				c.logger.Error("root generation aborted, master key verification failed", "error", err)
-				return nil, err
-			}
-		}
-	}
-
-	// Authentication in recovery mode is successful
-	if c.recoveryMode {
-		// Run any post unseal functions that are set
-		for _, v := range c.postRecoveryUnsealFuncs {
-			if err := v(); err != nil {
-				return nil, errwrap.Wrapf("failed to run post unseal func: {{err}}", err)
-			}
-		}
+	if err := strategy.authenticate(ctx, c, combinedKey); err != nil {
+		c.logger.Error("root generation aborted", "error", err.Error())
+		return nil, errwrap.Wrapf("root generation aborted: {{err}}", err)
 	}
 
 	// Run the generate strategy

vault/generate_root_recovery.go

@@ -2,7 +2,7 @@ package vault
 
 import (
 	"context"
-
+	"github.com/hashicorp/errwrap"
 	"github.com/hashicorp/vault/sdk/helper/base62"
 	"go.uber.org/atomic"
 )
@@ -19,6 +19,25 @@ type generateRecoveryToken struct {
 	token *atomic.String
 }
 
+func (g *generateRecoveryToken) authenticate(ctx context.Context, c *Core, combinedKey []byte) error {
+	key, err := c.unsealKeyToMasterKey(ctx, combinedKey)
+	if err != nil {
+		return errwrap.Wrapf("unable to authenticate: {{err}}", err)
+	}
+
+	// Use the retrieved master key to unseal the barrier
+	if err := c.barrier.Unseal(ctx, key); err != nil {
+		return errwrap.Wrapf("recovery operation token generation failed, cannot unseal barrier: {{err}}", err)
+	}
+
+	for _, v := range c.postRecoveryUnsealFuncs {
+		if err := v(); err != nil {
+			return errwrap.Wrapf("failed to run post unseal func: {{err}}", err)
+		}
+	}
+	return nil
+}
+
 func (g *generateRecoveryToken) generate(ctx context.Context, c *Core) (string, func(), error) {
 	id, err := base62.Random(TokenLength)
 	if err != nil {