Switch our tri-copy ca loading code to go-rootcerts

vendor/github.com/hashicorp/go-rootcerts/rootcerts.go

@@ -0,0 +1,103 @@
+package rootcerts
+
+import (
+	"crypto/tls"
+	"crypto/x509"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+)
+
+// Config determines where LoadCACerts will load certificates from. When both
+// CAFile and CAPath are blank, this library's functions will either load
+// system roots explicitly and return them, or set the CertPool to nil to allow
+// Go's standard library to load system certs.
+type Config struct {
+	// CAFile is a path to a PEM-encoded certificate file or bundle. Takes
+	// precedence over CAPath.
+	CAFile string
+
+	// CAPath is a path to a directory populated with PEM-encoded certificates.
+	CAPath string
+}
+
+// ConfigureTLS sets up the RootCAs on the provided tls.Config based on the
+// Config specified.
+func ConfigureTLS(t *tls.Config, c *Config) error {
+	if t == nil {
+		return nil
+	}
+	pool, err := LoadCACerts(c)
+	if err != nil {
+		return err
+	}
+	t.RootCAs = pool
+	return nil
+}
+
+// LoadCACerts loads a CertPool based on the Config specified.
+func LoadCACerts(c *Config) (*x509.CertPool, error) {
+	if c == nil {
+		c = &Config{}
+	}
+	if c.CAFile != "" {
+		return LoadCAFile(c.CAFile)
+	}
+	if c.CAPath != "" {
+		return LoadCAPath(c.CAPath)
+	}
+
+	return LoadSystemCAs()
+}
+
+// LoadCAFile loads a single PEM-encoded file from the path specified.
+func LoadCAFile(caFile string) (*x509.CertPool, error) {
+	pool := x509.NewCertPool()
+
+	pem, err := ioutil.ReadFile(caFile)
+	if err != nil {
+		return nil, fmt.Errorf("Error loading CA File: %s", err)
+	}
+
+	ok := pool.AppendCertsFromPEM(pem)
+	if !ok {
+		return nil, fmt.Errorf("Error loading CA File: Couldn't parse PEM in: %s", caFile)
+	}
+
+	return pool, nil
+}
+
+// LoadCAPath walks the provided path and loads all certificates encounted into
+// a pool.
+func LoadCAPath(caPath string) (*x509.CertPool, error) {
+	pool := x509.NewCertPool()
+	walkFn := func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+
+		if info.IsDir() {
+			return nil
+		}
+
+		pem, err := ioutil.ReadFile(path)
+		if err != nil {
+			return fmt.Errorf("Error loading file from CAPath: %s", err)
+		}
+
+		ok := pool.AppendCertsFromPEM(pem)
+		if !ok {
+			return fmt.Errorf("Error loading CA Path: Couldn't parse PEM in: %s", path)
+		}
+
+		return nil
+	}
+
+	err := filepath.Walk(caPath, walkFn)
+	if err != nil {
+		return nil, err
+	}
+
+	return pool, nil
+}