1 files changed, 182 insertions, 0 deletions
diff --git a/vendor/github.com/googleapis/enterprise-certificate-proxy/client/client.go b/vendor/github.com/googleapis/enterprise-certificate-proxy/client/client.go
new file mode 100644
index 0000000..aecaff5
--- /dev/null
+++ b/vendor/github.com/googleapis/enterprise-certificate-proxy/client/client.go
@@ -0,0 +1,182 @@
+// Copyright 2022 Google LLC.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package client is a cross-platform client for the signer binary (a.k.a."EnterpriseCertSigner").
+//
+// The signer binary is OS-specific, but exposes a standard set of APIs for the client to use.
+package client
+
+import (
+	"crypto"
+	"crypto/ecdsa"
+	"crypto/rsa"
+	"crypto/x509"
+	"encoding/gob"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
+	"net/rpc"
+	"os"
+	"os/exec"
+
+	"github.com/googleapis/enterprise-certificate-proxy/client/util"
+)
+
+const signAPI = "EnterpriseCertSigner.Sign"
+const certificateChainAPI = "EnterpriseCertSigner.CertificateChain"
+const publicKeyAPI = "EnterpriseCertSigner.Public"
+
+// A Connection wraps a pair of unidirectional streams as an io.ReadWriteCloser.
+type Connection struct {
+	io.ReadCloser
+	io.WriteCloser
+}
+
+// Close closes c's underlying ReadCloser and WriteCloser.
+func (c *Connection) Close() error {
+	rerr := c.ReadCloser.Close()
+	werr := c.WriteCloser.Close()
+	if rerr != nil {
+		return rerr
+	}
+	return werr
+}
+
+// If ECP Logging is enabled return true
+// Otherwise return false
+func enableECPLogging() bool {
+	if os.Getenv("ENABLE_ENTERPRISE_CERTIFICATE_LOGS") != "" {
+		return true
+	}
+
+	log.SetOutput(ioutil.Discard)
+	return false
+}
+
+func init() {
+	gob.Register(crypto.SHA256)
+	gob.Register(&rsa.PSSOptions{})
+}
+
+// SignArgs contains arguments to a crypto Signer.Sign method.
+type SignArgs struct {
+	Digest []byte            // The content to sign.
+	Opts   crypto.SignerOpts // Options for signing, such as Hash identifier.
+}
+
+// Key implements credential.Credential by holding the executed signer subprocess.
+type Key struct {
+	cmd       *exec.Cmd        // Pointer to the signer subprocess.
+	client    *rpc.Client      // Pointer to the rpc client that communicates with the signer subprocess.
+	publicKey crypto.PublicKey // Public key of loaded certificate.
+	chain     [][]byte         // Certificate chain of loaded certificate.
+}
+
+// CertificateChain returns the credential as a raw X509 cert chain. This contains the public key.
+func (k *Key) CertificateChain() [][]byte {
+	return k.chain
+}
+
+// Close closes the RPC connection and kills the signer subprocess.
+// Call this to free up resources when the Key object is no longer needed.
+func (k *Key) Close() error {
+	if err := k.cmd.Process.Kill(); err != nil {
+		return fmt.Errorf("failed to kill signer process: %w", err)
+	}
+	// Wait for cmd to exit and release resources. Since the process is forcefully killed, this
+	// will return a non-nil error (varies by OS), which we will ignore.
+	k.cmd.Wait()
+	// The Pipes connecting the RPC client should have been closed when the signer subprocess was killed.
+	// Calling `k.client.Close()` before `k.cmd.Process.Kill()` or `k.cmd.Wait()` _will_ cause a segfault.
+	if err := k.client.Close(); err.Error() != "close |0: file already closed" {
+		return fmt.Errorf("failed to close RPC connection: %w", err)
+	}
+	return nil
+}
+
+// Public returns the public key for this Key.
+func (k *Key) Public() crypto.PublicKey {
+	return k.publicKey
+}
+
+// Sign signs a message digest, using the specified signer options.
+func (k *Key) Sign(_ io.Reader, digest []byte, opts crypto.SignerOpts) (signed []byte, err error) {
+	if opts != nil && opts.HashFunc() != 0 && len(digest) != opts.HashFunc().Size() {
+		return nil, fmt.Errorf("Digest length of %v bytes does not match Hash function size of %v bytes", len(digest), opts.HashFunc().Size())
+	}
+	err = k.client.Call(signAPI, SignArgs{Digest: digest, Opts: opts}, &signed)
+	return
+}
+
+// Cred spawns a signer subprocess that listens on stdin/stdout to perform certificate
+// related operations, including signing messages with the private key.
+//
+// The signer binary path is read from the specified configFilePath, if provided.
+// Otherwise, use the default config file path.
+//
+// The config file also specifies which certificate the signer should use.
+func Cred(configFilePath string) (*Key, error) {
+	enableECPLogging()
+	if configFilePath == "" {
+		configFilePath = util.GetDefaultConfigFilePath()
+	}
+	enterpriseCertSignerPath, err := util.LoadSignerBinaryPath(configFilePath)
+	if err != nil {
+		return nil, err
+	}
+	k := &Key{
+		cmd: exec.Command(enterpriseCertSignerPath, configFilePath),
+	}
+
+	// Redirect errors from subprocess to parent process.
+	k.cmd.Stderr = os.Stderr
+
+	// RPC client will communicate with subprocess over stdin/stdout.
+	kin, err := k.cmd.StdinPipe()
+	if err != nil {
+		return nil, err
+	}
+	kout, err := k.cmd.StdoutPipe()
+	if err != nil {
+		return nil, err
+	}
+	k.client = rpc.NewClient(&Connection{kout, kin})
+
+	if err := k.cmd.Start(); err != nil {
+		return nil, fmt.Errorf("starting enterprise cert signer subprocess: %w", err)
+	}
+
+	if err := k.client.Call(certificateChainAPI, struct{}{}, &k.chain); err != nil {
+		return nil, fmt.Errorf("failed to retrieve certificate chain: %w", err)
+	}
+
+	var publicKeyBytes []byte
+	if err := k.client.Call(publicKeyAPI, struct{}{}, &publicKeyBytes); err != nil {
+		return nil, fmt.Errorf("failed to retrieve public key: %w", err)
+	}
+
+	publicKey, err := x509.ParsePKIXPublicKey(publicKeyBytes)
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse public key: %w", err)
+	}
+
+	var ok bool
+	k.publicKey, ok = publicKey.(crypto.PublicKey)
+	if !ok {
+		return nil, fmt.Errorf("invalid public key type: %T", publicKey)
+	}
+
+	switch pub := k.publicKey.(type) {
+	case *rsa.PublicKey:
+		if pub.Size() < 256 {
+			return nil, fmt.Errorf("RSA modulus size is less than 2048 bits: %v", pub.Size()*8)
+		}
+	case *ecdsa.PublicKey:
+	default:
+		return nil, fmt.Errorf("unsupported public key type: %v", pub)
+	}
+
+	return k, nil
+}