Parse CA certificate to catch more specific errors

helper/tlsutil/config.go

@@ -3,6 +3,7 @@ package tlsutil
 import (
 	"crypto/tls"
 	"crypto/x509"
+	"encoding/pem"
 	"fmt"
 	"io/ioutil"
 	"net"
@@ -146,8 +147,18 @@ func (c *Config) AppendCA(pool *x509.CertPool) error {
 		return fmt.Errorf("Failed to read CA file: %v", err)
 	}
 
+	block, _ := pem.Decode([]byte(data))
+	if block == nil {
+		return fmt.Errorf("Failed to decode CA file from pem format")
+	}
+
+	// Parse the certificate to ensure that it is properly formatted
+	if _, err := x509.ParseCertificates(block.Bytes); err != nil {
+		return fmt.Errorf("Failed to parse CA file: %v", err)
+	}
+
 	if !pool.AppendCertsFromPEM(data) {
-		return fmt.Errorf("Failed to parse any CA certificates")
+		return fmt.Errorf("Failed to add any CA certificates")
 	}
 
 	return nil

helper/tlsutil/config_test.go

@@ -7,6 +7,7 @@ import (
 	"io"
 	"io/ioutil"
 	"net"
+	"os"
 	"strings"
 	"testing"
 
@@ -26,14 +27,55 @@ const (
 )
 
 func TestConfig_AppendCA_None(t *testing.T) {
+	require := require.New(t)
+
 	conf := &Config{}
 	pool := x509.NewCertPool()
 	err := conf.AppendCA(pool)
-	if err != nil {
-		t.Fatalf("err: %v", err)
+
+	require.Nil(err)
+}
+
+func TestConfig_AppendCA_Valid(t *testing.T) {
+	require := require.New(t)
+
+	conf := &Config{
+		CAFile: cacert,
+	}
+	pool := x509.NewCertPool()
+	err := conf.AppendCA(pool)
+
+	require.Nil(err)
+}
+
+func TestConfig_AppendCA_Invalid(t *testing.T) {
+	require := require.New(t)
+	{
+		conf := &Config{
+			CAFile: "invalidFile",
+		}
+		pool := x509.NewCertPool()
+		err := conf.AppendCA(pool)
+		require.NotNil(err)
+		require.Contains(err.Error(), "Failed to read CA file")
+		require.Equal(len(pool.Subjects()), 0)
 	}
-	if len(pool.Subjects()) != 0 {
-		t.Fatalf("bad: %v", pool.Subjects())
+
+	{
+		tmpFile, err := ioutil.TempFile("/tmp", "test_ca_file")
+		require.Nil(err)
+		defer os.Remove(tmpFile.Name())
+		_, err = tmpFile.Write([]byte("Invalid CA Content!"))
+		require.Nil(err)
+
+		conf := &Config{
+			CAFile: tmpFile.Name(),
+		}
+		pool := x509.NewCertPool()
+		err = conf.AppendCA(pool)
+		require.NotNil(err)
+		require.Contains(err.Error(), "Failed to decode CA file from pem format")
+		require.Equal(len(pool.Subjects()), 0)
 	}
 }