WFE/nonce: Add NonceHMACKey field

cmd/boulder-wfe2/main.go

@@ -71,13 +71,23 @@ type Config struct {
 		// local and remote nonce-service instances.
 		RedeemNonceService *cmd.GRPCClientConfig `validate:"required"`
 
+		// NonceHMACKey is a path to a file containing an HMAC key which is a
+		// secret used for deriving the prefix of each nonce instance. It should
+		// contain 256 bits (32 bytes) of random data to be suitable as an
+		// HMAC-SHA256 key (e.g. the output of `openssl rand -hex 32`). In a
+		// multi-DC deployment this value should be the same across all
+		// boulder-wfe and nonce-service instances.
+		NonceHMACKey cmd.HMACKeyConfig `validate:"-"`
+
 		// NoncePrefixKey is a secret used for deriving the prefix of each nonce
 		// instance. It should contain 256 bits of random data to be suitable as
 		// an HMAC-SHA256 key (e.g. the output of `openssl rand -hex 32`). In a
 		// multi-DC deployment this value should be the same across all
 		// boulder-wfe and nonce-service instances.
 		//
-		// TODO(#7632) Update this to use the new HMACKeyConfig.
+		// TODO(#7632): Remove this.
+		//
+		// Deprecated: Use NonceHMACKey instead.
 		NoncePrefixKey cmd.PasswordConfig `validate:"-"`
 
 		// Chains is a list of lists of certificate filenames. Each inner list is
@@ -295,9 +305,15 @@ func main() {
 	}
 
 	var noncePrefixKey string
-	if c.WFE.NoncePrefixKey.PasswordFile != "" {
+	if c.WFE.NonceHMACKey.KeyFile != "" {
+		keyByte, err := c.WFE.NonceHMACKey.Load()
+		cmd.FailOnError(err, "Failed to load nonceHMACKey file")
+		noncePrefixKey = string(keyByte)
+	} else if c.WFE.NoncePrefixKey.PasswordFile != "" {
 		noncePrefixKey, err = c.WFE.NoncePrefixKey.Pass()
-		cmd.FailOnError(err, "Failed to load noncePrefixKey")
+		cmd.FailOnError(err, "Failed to load noncePrefixKey file")
+	} else {
+		cmd.Fail("NonceHMACKey KeyFile or NoncePrefixKey PasswordFile must be set")
 	}
 
 	getNonceConn, err := bgrpc.ClientSetup(c.WFE.GetNonceService, tlsConfig, stats, clk)

cmd/config.go

@@ -572,7 +572,7 @@ func (hc *HMACKeyConfig) Load() ([]byte, error) {
 
 	if len(trimmed) != 32 {
 		return nil, fmt.Errorf(
-			"validating unpauseHMACKey, length must be 32 alphanumeric characters, got %d",
+			"validating HMAC key, length must be 32 alphanumeric characters, got %d",
 			len(trimmed),
 		)
 	}

cmd/nonce-service/main.go

@@ -19,23 +19,25 @@ type Config struct {
 
 		MaxUsed int
 
-		// UseDerivablePrefix indicates whether to use a nonce prefix derived
-		// from the gRPC listening address. If this is false, the nonce prefix
-		// will be the value of the NoncePrefix field. If this is true, the
-		// NoncePrefixKey field is required.
-		// TODO(#6610): Remove this.
-		//
-		// Deprecated: this value is ignored, and treated as though it is always true.
-		UseDerivablePrefix bool `validate:"-"`
+		// NonceHMACKey is a path to a file containing an HMAC key which is a
+		// secret used for deriving the prefix of each nonce instance. It should
+		// contain 256 bits (32 bytes) of random data to be suitable as an
+		// HMAC-SHA256 key (e.g. the output of `openssl rand -hex 32`). In a
+		// multi-DC deployment this value should be the same across all
+		// boulder-wfe and nonce-service instances.
+		NonceHMACKey cmd.HMACKeyConfig `validate:"required_without_all=NoncePrefixKey,structonly"`
 
 		// NoncePrefixKey is a secret used for deriving the prefix of each nonce
 		// instance. It should contain 256 bits (32 bytes) of random data to be
 		// suitable as an HMAC-SHA256 key (e.g. the output of `openssl rand -hex
 		// 32`). In a multi-DC deployment this value should be the same across
 		// all boulder-wfe and nonce-service instances.
 		//
-		// TODO(#7632) Update this to use the new HMACKeyConfig.
-		NoncePrefixKey cmd.PasswordConfig `validate:"required"`
+		// TODO(#7632): Remove this and change `NonceHMACKey`'s validation to
+		// just `required.`
+		//
+		// Deprecated: Use NonceHMACKey instead.
+		NoncePrefixKey cmd.PasswordConfig `validate:"required_without_all=NonceHMACKey,structonly"`
 
 		Syslog        cmd.SyslogConfig
 		OpenTelemetry cmd.OpenTelemetryConfig
@@ -84,12 +86,18 @@ func main() {
 		c.NonceService.DebugAddr = *debugAddr
 	}
 
-	if c.NonceService.NoncePrefixKey.PasswordFile == "" {
-		cmd.Fail("NoncePrefixKey PasswordFile must be set")
+	var key string
+	if c.NonceService.NonceHMACKey.KeyFile != "" {
+		keyByte, err := c.NonceService.NonceHMACKey.Load()
+		cmd.FailOnError(err, "Failed to load 'nonceHMACKey' file.")
+		key = string(keyByte)
+	} else if c.NonceService.NoncePrefixKey.PasswordFile != "" {
+		key, err = c.NonceService.NoncePrefixKey.Pass()
+		cmd.FailOnError(err, "Failed to load 'noncePrefixKey' file.")
+	} else {
+		cmd.Fail("NonceHMACKey KeyFile or NoncePrefixKey PasswordFile must be set")
 	}
 
-	key, err := c.NonceService.NoncePrefixKey.Pass()
-	cmd.FailOnError(err, "Failed to load 'noncePrefixKey' file.")
 	noncePrefix, err := derivePrefix(key, c.NonceService.GRPC.Address)
 	cmd.FailOnError(err, "Failed to derive nonce prefix")
 

test/config-next/nonce-a.json

@@ -1,8 +1,8 @@
 {
 	"NonceService": {
 		"maxUsed": 131072,
-		"noncePrefixKey": {
-			"passwordFile": "test/secrets/nonce_prefix_key"
+		"nonceHMACKey": {
+			"keyFile": "test/secrets/nonce_prefix_key"
 		},
 		"syslog": {
 			"stdoutLevel": 6,

test/config-next/nonce-b.json

@@ -1,8 +1,8 @@
 {
 	"NonceService": {
 		"maxUsed": 131072,
-		"noncePrefixKey": {
-			"passwordFile": "test/secrets/nonce_prefix_key"
+		"nonceHMACKey": {
+			"keyFile": "test/secrets/nonce_prefix_key"
 		},
 		"syslog": {
 			"stdoutLevel": 6,

test/config-next/wfe2.json

@@ -68,8 +68,8 @@
 			"noWaitForReady": true,
 			"hostOverride": "nonce.boulder"
 		},
-		"noncePrefixKey": {
-			"passwordFile": "test/secrets/nonce_prefix_key"
+		"nonceHMACKey": {
+			"keyFile": "test/secrets/nonce_prefix_key"
 		},
 		"chains": [
 			[

test/config/nonce-a.json

@@ -1,7 +1,6 @@
 {
 	"NonceService": {
 		"maxUsed": 131072,
-		"useDerivablePrefix": true,
 		"noncePrefixKey": {
 			"passwordFile": "test/secrets/nonce_prefix_key"
 		},

test/config/nonce-b.json

@@ -1,7 +1,6 @@
 {
 	"NonceService": {
 		"maxUsed": 131072,
-		"useDerivablePrefix": true,
 		"noncePrefixKey": {
 			"passwordFile": "test/secrets/nonce_prefix_key"
 		},

test/integration/nonce_test.go

@@ -24,6 +24,7 @@ type nonceBalancerTestConfig struct {
 		GetNonceService    *cmd.GRPCClientConfig
 		RedeemNonceService *cmd.GRPCClientConfig
 		NoncePrefixKey     cmd.PasswordConfig
+		NonceHMACKey       cmd.HMACKeyConfig
 	}
 }
 
@@ -41,8 +42,14 @@ func TestNonceBalancer_NoBackendMatchingPrefix(t *testing.T) {
 	tlsConfig, err := c.NotWFE.TLS.Load(metrics.NoopRegisterer)
 	test.AssertNotError(t, err, "Could not load TLS config")
 
-	rncKey, err := c.NotWFE.NoncePrefixKey.Pass()
-	test.AssertNotError(t, err, "Failed to load noncePrefixKey")
+	var rncKey string
+	rncKeyByte, err := c.NotWFE.NonceHMACKey.Load()
+	if err != nil {
+		rncKey, err = c.NotWFE.NoncePrefixKey.Pass()
+		test.AssertNotError(t, err, "Failed to load nonceHMACKey or noncePrefixKey")
+	} else {
+		rncKey = string(rncKeyByte)
+	}
 
 	clk := clock.New()
 

test/integration/testdata/nonce-client.json

@@ -32,8 +32,8 @@
 			"noWaitForReady": true,
 			"hostOverride": "nonce.boulder"
 		},
-		"noncePrefixKey": {
-			"passwordFile": "test/secrets/nonce_prefix_key"
+		"nonceHMACKey": {
+			"keyFile": "test/secrets/nonce_prefix_key"
 		}
     }
 }

test/secrets/nonce_prefix_key

@@ -1 +1 @@
-3b8c758dd85e113ea340ce0b3a99f389d40a308548af94d1730a7692c1874f1f
+3b8c758dd85e113ea340ce0b3a99f389