101 lines
2.8 KiB
Go
101 lines
2.8 KiB
Go
// Package crypto handles the RSA key material every node uses for
|
|
// mutual TLS authentication and for the trust-store fingerprint pinning.
|
|
//
|
|
// Keys are RSA-3072 (NIST 112-bit security, well within the safe band
|
|
// through ~2030). They live PEM-encoded under <data_dir>/keys/.
|
|
package crypto
|
|
|
|
import (
|
|
"crypto/rand"
|
|
"crypto/rsa"
|
|
"crypto/x509"
|
|
"encoding/pem"
|
|
"errors"
|
|
"fmt"
|
|
"os"
|
|
|
|
"github.com/jasper/quptime/internal/config"
|
|
)
|
|
|
|
// KeySize is the RSA modulus size used by qu.
|
|
const KeySize = 3072
|
|
|
|
// GenerateKeyPair creates a fresh RSA keypair and writes the private,
|
|
// public, and self-signed certificate to the standard paths.
|
|
// It refuses to overwrite existing keys.
|
|
func GenerateKeyPair(commonName string) (*rsa.PrivateKey, error) {
|
|
if _, err := os.Stat(config.PrivateKeyPath()); err == nil {
|
|
return nil, errors.New("key material already exists; refusing to overwrite")
|
|
}
|
|
if err := config.EnsureDataDir(); err != nil {
|
|
return nil, err
|
|
}
|
|
priv, err := rsa.GenerateKey(rand.Reader, KeySize)
|
|
if err != nil {
|
|
return nil, fmt.Errorf("generate rsa key: %w", err)
|
|
}
|
|
if err := writePEM(config.PrivateKeyPath(), "RSA PRIVATE KEY",
|
|
x509.MarshalPKCS1PrivateKey(priv), 0o600); err != nil {
|
|
return nil, err
|
|
}
|
|
pubDER, err := x509.MarshalPKIXPublicKey(&priv.PublicKey)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
if err := writePEM(config.PublicKeyPath(), "PUBLIC KEY", pubDER, 0o644); err != nil {
|
|
return nil, err
|
|
}
|
|
certDER, err := buildSelfSignedCert(priv, commonName)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
if err := writePEM(config.CertFilePath(), "CERTIFICATE", certDER, 0o644); err != nil {
|
|
return nil, err
|
|
}
|
|
return priv, nil
|
|
}
|
|
|
|
// LoadPrivateKey reads the on-disk RSA private key.
|
|
func LoadPrivateKey() (*rsa.PrivateKey, error) {
|
|
raw, err := os.ReadFile(config.PrivateKeyPath())
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
block, _ := pem.Decode(raw)
|
|
if block == nil {
|
|
return nil, errors.New("private key: no PEM block")
|
|
}
|
|
switch block.Type {
|
|
case "RSA PRIVATE KEY":
|
|
return x509.ParsePKCS1PrivateKey(block.Bytes)
|
|
case "PRIVATE KEY":
|
|
k, err := x509.ParsePKCS8PrivateKey(block.Bytes)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
rk, ok := k.(*rsa.PrivateKey)
|
|
if !ok {
|
|
return nil, errors.New("private key: not RSA")
|
|
}
|
|
return rk, nil
|
|
default:
|
|
return nil, fmt.Errorf("private key: unexpected PEM type %q", block.Type)
|
|
}
|
|
}
|
|
|
|
// LoadCertPEM reads the self-signed cert file (used as the TLS leaf).
|
|
func LoadCertPEM() ([]byte, error) {
|
|
return os.ReadFile(config.CertFilePath())
|
|
}
|
|
|
|
// LoadPublicKeyPEM reads the public-key PEM (exchanged out of band
|
|
// during invite / join).
|
|
func LoadPublicKeyPEM() ([]byte, error) {
|
|
return os.ReadFile(config.PublicKeyPath())
|
|
}
|
|
|
|
func writePEM(path, blockType string, der []byte, perm os.FileMode) error {
|
|
encoded := pem.EncodeToMemory(&pem.Block{Type: blockType, Bytes: der})
|
|
return config.AtomicWrite(path, encoded, perm)
|
|
}
|