Allow reading ECDSA key files containing parameter blocks

pkg/serviceaccount/jwt.go

@@ -73,12 +73,26 @@ func ReadPrivateKey(file string) (interface{}, error) {
 
 // ReadPrivateKeyFromPEM is a helper function for reading a private key from a PEM-encoded file
 func ReadPrivateKeyFromPEM(data []byte) (interface{}, error) {
-	if key, err := jwt.ParseRSAPrivateKeyFromPEM(data); err == nil {
+	var block *pem.Block
+	for {
+		// read the next block
+		block, data = pem.Decode(data)
+		if block == nil {
+			break
+		}
+
+		// get PEM bytes for just this block
+		blockData := pem.EncodeToMemory(block)
+		if key, err := jwt.ParseRSAPrivateKeyFromPEM(blockData); err == nil {
 			return key, nil
 		}
-	if key, err := jwt.ParseECPrivateKeyFromPEM(data); err == nil {
+		if key, err := jwt.ParseECPrivateKeyFromPEM(blockData); err == nil {
 			return key, nil
 		}
+
+		// tolerate non-key PEM blocks for compatibility with things like "EC PARAMETERS" blocks
+		// originally, only the first PEM block was parsed and expected to be a key block
+	}
 	return nil, fmt.Errorf("data does not contain a valid RSA or ECDSA private key")
 }
 

pkg/serviceaccount/jwt_test.go

@@ -81,6 +81,17 @@ X024wzbiw1q07jFCyfQmODzURAx1VNT7QVUMdz/N8vy47/H40AZJ
 -----END RSA PRIVATE KEY-----
 `
 
+// openssl ecparam -name prime256v1 -genkey -out ecdsa256params.pem
+const ecdsaPrivateKeyWithParams = `-----BEGIN EC PARAMETERS-----
+BggqhkjOPQMBBw==
+-----END EC PARAMETERS-----
+-----BEGIN EC PRIVATE KEY-----
+MHcCAQEEIJ9LWDj3ZWe9CksPV7mZjD2dYXG9icfzxadCRwd3vr1toAoGCCqGSM49
+AwEHoUQDQgAEaLNEpzbaaNTCkKjBVj7sxpfJ1ifJQGNvcck4nrzcwFRuujwVDDJh
+95iIGwKCQeSg+yhdN6Q/p2XaxNIZlYmUhg==
+-----END EC PRIVATE KEY-----
+`
+
 // openssl ecparam -name prime256v1 -genkey -noout -out ecdsa256.pem
 const ecdsaPrivateKey = `-----BEGIN EC PRIVATE KEY-----
 MHcCAQEEIEZmTmUhuanLjPA2CLquXivuwBDHTt5XYwgIr/kA1LtRoAoGCCqGSM49
@@ -110,6 +121,10 @@ func TestReadPrivateKey(t *testing.T) {
 	}
 	defer os.Remove(f.Name())
 
+	if _, err := serviceaccount.ReadPrivateKey(f.Name()); err == nil {
+		t.Fatalf("Expected error reading key from empty file, got none")
+	}
+
 	if err := ioutil.WriteFile(f.Name(), []byte(rsaPrivateKey), os.FileMode(0600)); err != nil {
 		t.Fatalf("error writing private key to tmpfile: %v", err)
 	}
@@ -123,6 +138,13 @@ func TestReadPrivateKey(t *testing.T) {
 	if _, err := serviceaccount.ReadPrivateKey(f.Name()); err != nil {
 		t.Fatalf("error reading private ECDSA key: %v", err)
 	}
+
+	if err := ioutil.WriteFile(f.Name(), []byte(ecdsaPrivateKeyWithParams), os.FileMode(0600)); err != nil {
+		t.Fatalf("error writing private key to tmpfile: %v", err)
+	}
+	if _, err := serviceaccount.ReadPrivateKey(f.Name()); err != nil {
+		t.Fatalf("error reading private ECDSA key with params: %v", err)
+	}
 }
 
 func TestReadPublicKeys(t *testing.T) {
@@ -132,6 +154,10 @@ func TestReadPublicKeys(t *testing.T) {
 	}
 	defer os.Remove(f.Name())
 
+	if _, err := serviceaccount.ReadPublicKeys(f.Name()); err == nil {
+		t.Fatalf("Expected error reading keys from empty file, got none")
+	}
+
 	if err := ioutil.WriteFile(f.Name(), []byte(rsaPublicKey), os.FileMode(0600)); err != nil {
 		t.Fatalf("error writing public key to tmpfile: %v", err)
 	}