Initial QSfera import

Server/pkg/crypto/gencert.go

@@ -0,0 +1,167 @@
+package crypto
+
+import (
+	"crypto/ecdsa"
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/tls"
+	"crypto/x509"
+	"encoding/pem"
+	"fmt"
+	"net"
+	"os"
+	"path/filepath"
+
+	"github.com/qsfera/server/pkg/log"
+	mtls "go-micro.dev/v4/util/tls"
+)
+
+var (
+	defaultHosts = []string{"127.0.0.1", "localhost"}
+)
+
+// GenCert generates TLS-Certificates. This function has side effects: it creates the respective certificate / key pair at
+// the destination locations unless the tuple already exists, if that is the case, this is a noop.
+func GenCert(certName string, keyName string, l log.Logger) error {
+	var pk *rsa.PrivateKey
+	var err error
+
+	pk, err = rsa.GenerateKey(rand.Reader, 2048)
+	if err != nil {
+		return err
+	}
+
+	_, certErr := os.Stat(certName)
+	_, keyErr := os.Stat(keyName)
+
+	if certErr == nil || keyErr == nil {
+		l.Info().Msg(
+			fmt.Sprintf("%v certificate / key pair already present. skipping acme certificate generation",
+				filepath.Base(certName)))
+		return nil
+	}
+
+	if err := persistCertificate(certName, l, pk); err != nil {
+		l.Fatal().Err(err).Msg("failed to store certificate")
+	}
+
+	if err := persistKey(keyName, l, pk); err != nil {
+		l.Fatal().Err(err).Msg("failed to store key")
+	}
+
+	return nil
+}
+
+// GenTempCertForAddr generates temporary TLS-Certificates in memory.
+func GenTempCertForAddr(addr string) (tls.Certificate, error) {
+	subjects := defaultHosts
+
+	if host, _, err := net.SplitHostPort(addr); err == nil && host != "" {
+		subjects = []string{host}
+	}
+	return mtls.Certificate(subjects...)
+}
+
+// persistCertificate generates a certificate using pk as private key and proceeds to store it into a file named certName.
+func persistCertificate(certName string, l log.Logger, pk any) error {
+	if err := ensureExistsDir(certName); err != nil {
+		return fmt.Errorf("creating certificate destination: %s", certName)
+	}
+
+	certificate, err := generateCertificate(pk)
+	if err != nil {
+		return fmt.Errorf("creating certificate: %s", filepath.Dir(certName))
+	}
+
+	certOut, err := os.Create(certName)
+	if err != nil {
+		return fmt.Errorf("failed to open `%v` for writing", certName)
+	}
+
+	err = pem.Encode(certOut, &pem.Block{Type: "CERTIFICATE", Bytes: certificate})
+	if err != nil {
+		return fmt.Errorf("failed to encode certificate")
+	}
+
+	err = certOut.Close()
+	if err != nil {
+		return fmt.Errorf("failed to write cert")
+	}
+	l.Info().Msg(fmt.Sprintf("written certificate to %v", certName))
+
+	return nil
+}
+
+// genCert generates a self signed certificate using a random rsa key.
+func generateCertificate(pk any) ([]byte, error) {
+	for _, h := range defaultHosts {
+		if ip := net.ParseIP(h); ip != nil {
+			acmeTemplate.IPAddresses = append(acmeTemplate.IPAddresses, ip)
+		} else {
+			acmeTemplate.DNSNames = append(acmeTemplate.DNSNames, h)
+		}
+	}
+
+	return x509.CreateCertificate(rand.Reader, &acmeTemplate, &acmeTemplate, publicKey(pk), pk)
+}
+
+// persistKey persists the private key used to generate the certificate at the configured location.
+func persistKey(destination string, l log.Logger, pk any) error {
+	if err := ensureExistsDir(destination); err != nil {
+		return fmt.Errorf("creating key destination: %s", destination)
+	}
+
+	keyOut, err := os.OpenFile(destination, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
+	if err != nil {
+		return fmt.Errorf("failed to open %v for writing", destination)
+	}
+	err = pem.Encode(keyOut, pemBlockForKey(pk, l))
+	if err != nil {
+		return fmt.Errorf("failed to encode key")
+	}
+
+	err = keyOut.Close()
+	if err != nil {
+		return fmt.Errorf("failed to write key")
+	}
+	l.Info().Msg(fmt.Sprintf("written key to %v", destination))
+
+	return nil
+}
+
+func publicKey(pk any) any {
+	switch k := pk.(type) {
+	case *rsa.PrivateKey:
+		return &k.PublicKey
+	case *ecdsa.PrivateKey:
+		return &k.PublicKey
+	default:
+		return nil
+	}
+}
+
+func pemBlockForKey(pk any, l log.Logger) *pem.Block {
+	switch k := pk.(type) {
+	case *rsa.PrivateKey:
+		return &pem.Block{Type: "RSA PRIVATE KEY", Bytes: x509.MarshalPKCS1PrivateKey(k)}
+	case *ecdsa.PrivateKey:
+		b, err := x509.MarshalECPrivateKey(k)
+		if err != nil {
+			l.Fatal().Err(err).Msg("Unable to marshal ECDSA private key")
+		}
+		return &pem.Block{Type: "EC PRIVATE KEY", Bytes: b}
+	default:
+		return nil
+	}
+}
+
+func ensureExistsDir(uri string) error {
+	certPath := filepath.Dir(uri)
+	if _, err := os.Stat(certPath); os.IsNotExist(err) {
+		err = os.MkdirAll(certPath, 0700)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}