Export keys in PKCS8 format

History.md

@@ -49,6 +49,9 @@ Version 2.2.0 (not yet released)
   [[GitHub #185]](https://github.com/ruby/openssl/pull/185)
 * Allow recipient's certificate to be omitted in PCKS7#decrypt.
   [[GitHub #183]](https://github.com/ruby/openssl/pull/183)
+* Add instance methods for exporting public and private keys in PKCS8 format
+  to `OpenSSL::PKey` classes: `private_to_der`, `private_to_pem`,
+  `public_to_der` and `public_to_pem`.
 
 Version 2.1.2
 =============

ext/openssl/ossl_pkey.c

@@ -167,21 +167,27 @@ ossl_pkey_new_from_data(int argc, VALUE *argv, VALUE self)
     pass = ossl_pem_passwd_value(pass);
 
     bio = ossl_obj2bio(&data);
-    if (!(pkey = d2i_PrivateKey_bio(bio, NULL))) {
-	OSSL_BIO_reset(bio);
-	if (!(pkey = PEM_read_bio_PrivateKey(bio, NULL, ossl_pem_passwd_cb, (void *)pass))) {
-	    OSSL_BIO_reset(bio);
-	    if (!(pkey = d2i_PUBKEY_bio(bio, NULL))) {
-		OSSL_BIO_reset(bio);
-		pkey = PEM_read_bio_PUBKEY(bio, NULL, ossl_pem_passwd_cb, (void *)pass);
-	    }
-	}
-    }
+    if ((pkey = d2i_PrivateKey_bio(bio, NULL)))
+	goto ok;
+    OSSL_BIO_reset(bio);
+    if ((pkey = d2i_PKCS8PrivateKey_bio(bio, NULL, ossl_pem_passwd_cb, (void *)pass)))
+	goto ok;
+    OSSL_BIO_reset(bio);
+    if ((pkey = d2i_PUBKEY_bio(bio, NULL)))
+	goto ok;
+    OSSL_BIO_reset(bio);
+    /* PEM_read_bio_PrivateKey() also parses PKCS #8 formats */
+    if ((pkey = PEM_read_bio_PrivateKey(bio, NULL, ossl_pem_passwd_cb, (void *)pass)))
+	goto ok;
+    OSSL_BIO_reset(bio);
+    if ((pkey = PEM_read_bio_PUBKEY(bio, NULL, NULL, NULL)))
+	goto ok;
 
     BIO_free(bio);
-    if (!pkey)
-	ossl_raise(ePKeyError, "Could not parse PKey");
+    ossl_raise(ePKeyError, "Could not parse PKey");
 
+ok:
+    BIO_free(bio);
     return ossl_pkey_new(pkey);
 }
 
@@ -293,6 +299,124 @@ ossl_pkey_initialize(VALUE self)
     return self;
 }
 
+static VALUE
+do_pkcs8_export(int argc, VALUE *argv, VALUE self, int to_der)
+{
+    EVP_PKEY *pkey;
+    VALUE cipher, pass;
+    const EVP_CIPHER *enc = NULL;
+    BIO *bio;
+
+    GetPKey(self, pkey);
+    rb_scan_args(argc, argv, "02", &cipher, &pass);
+    if (argc > 0) {
+	/*
+	 * TODO: EncryptedPrivateKeyInfo actually has more options.
+	 * Should they be exposed?
+	 */
+	enc = ossl_evp_get_cipherbyname(cipher);
+	pass = ossl_pem_passwd_value(pass);
+    }
+
+    bio = BIO_new(BIO_s_mem());
+    if (!bio)
+	ossl_raise(ePKeyError, "BIO_new");
+    if (to_der) {
+	if (!i2d_PKCS8PrivateKey_bio(bio, pkey, enc, NULL, 0,
+				     ossl_pem_passwd_cb, (void *)pass)) {
+	    BIO_free(bio);
+	    ossl_raise(ePKeyError, "i2d_PKCS8PrivateKey_bio");
+	}
+    }
+    else {
+	if (!PEM_write_bio_PKCS8PrivateKey(bio, pkey, enc, NULL, 0,
+					   ossl_pem_passwd_cb, (void *)pass)) {
+	    BIO_free(bio);
+	    ossl_raise(ePKeyError, "PEM_write_bio_PKCS8PrivateKey");
+	}
+    }
+    return ossl_membio2str(bio);
+}
+
+/*
+ * call-seq:
+ *    pkey.private_to_der                   -> string
+ *    pkey.private_to_der(cipher, password) -> string
+ *
+ * Serializes the private key to DER-encoded PKCS #8 format. If called without
+ * arguments, unencrypted PKCS #8 PrivateKeyInfo format is used. If called with
+ * a cipher name and a password, PKCS #8 EncryptedPrivateKeyInfo format with
+ * PBES2 encryption scheme is used.
+ */
+static VALUE
+ossl_pkey_private_to_der(int argc, VALUE *argv, VALUE self)
+{
+    return do_pkcs8_export(argc, argv, self, 1);
+}
+
+/*
+ * call-seq:
+ *    pkey.private_to_pem                   -> string
+ *    pkey.private_to_pem(cipher, password) -> string
+ *
+ * Serializes the private key to PEM-encoded PKCS #8 format. See #private_to_der
+ * for more details.
+ */
+static VALUE
+ossl_pkey_private_to_pem(int argc, VALUE *argv, VALUE self)
+{
+    return do_pkcs8_export(argc, argv, self, 0);
+}
+
+static VALUE
+do_spki_export(VALUE self, int to_der)
+{
+    EVP_PKEY *pkey;
+    BIO *bio;
+
+    GetPKey(self, pkey);
+    bio = BIO_new(BIO_s_mem());
+    if (!bio)
+	ossl_raise(ePKeyError, "BIO_new");
+    if (to_der) {
+	if (!i2d_PUBKEY_bio(bio, pkey)) {
+	    BIO_free(bio);
+	    ossl_raise(ePKeyError, "i2d_PUBKEY_bio");
+	}
+    }
+    else {
+	if (!PEM_write_bio_PUBKEY(bio, pkey)) {
+	    BIO_free(bio);
+	    ossl_raise(ePKeyError, "PEM_write_bio_PUBKEY");
+	}
+    }
+    return ossl_membio2str(bio);
+}
+
+/*
+ * call-seq:
+ *    pkey.public_to_der -> string
+ *
+ * Serializes the public key to DER-encoded X.509 SubjectPublicKeyInfo format.
+ */
+static VALUE
+ossl_pkey_public_to_der(VALUE self)
+{
+    return do_spki_export(self, 1);
+}
+
+/*
+ * call-seq:
+ *    pkey.public_to_pem -> string
+ *
+ * Serializes the public key to PEM-encoded X.509 SubjectPublicKeyInfo format.
+ */
+static VALUE
+ossl_pkey_public_to_pem(VALUE self)
+{
+    return do_spki_export(self, 0);
+}
+
 /*
  *  call-seq:
  *      pkey.sign(digest, data) -> String
@@ -491,6 +615,10 @@ Init_ossl_pkey(void)
 
     rb_define_alloc_func(cPKey, ossl_pkey_alloc);
     rb_define_method(cPKey, "initialize", ossl_pkey_initialize, 0);
+    rb_define_method(cPKey, "private_to_der", ossl_pkey_private_to_der, -1);
+    rb_define_method(cPKey, "private_to_pem", ossl_pkey_private_to_pem, -1);
+    rb_define_method(cPKey, "public_to_der", ossl_pkey_public_to_der, 0);
+    rb_define_method(cPKey, "public_to_pem", ossl_pkey_public_to_pem, 0);
 
     rb_define_method(cPKey, "sign", ossl_pkey_sign, 2);
     rb_define_method(cPKey, "verify", ossl_pkey_verify, 3);

test/test_pkey_rsa.rb

@@ -356,6 +356,85 @@ def test_pem_passwd
     }
   end
 
+  def test_private_encoding
+    rsa1024 = Fixtures.pkey("rsa1024")
+    asn1 = OpenSSL::ASN1::Sequence([
+      OpenSSL::ASN1::Integer(0),
+      OpenSSL::ASN1::Sequence([
+        OpenSSL::ASN1::ObjectId("rsaEncryption"),
+        OpenSSL::ASN1::Null(nil)
+      ]),
+      OpenSSL::ASN1::OctetString(rsa1024.to_der)
+    ])
+    assert_equal asn1.to_der, rsa1024.private_to_der
+    assert_same_rsa rsa1024, OpenSSL::PKey.read(asn1.to_der)
+
+    pem = <<~EOF
+    -----BEGIN PRIVATE KEY-----
+    MIICeAIBADANBgkqhkiG9w0BAQEFAASCAmIwggJeAgEAAoGBAMvCxLDUQKc+1P4+
+    Q6AeFwYDvWfALb+cvzlUEadGoPE6qNWHsLFoo8RFgeyTgE8KQTduu1OE9Zz2SMcR
+    BDu5/1jWtsLPSVrI2ofLLBARUsWanVyki39DeB4u/xkP2mKGjAokPIwOI3oCthSZ
+    lzO9bj3voxTf6XngTqUX8l8URTmHAgMBAAECgYEApKX8xBqvJ7XI7Kypfo/x8MVC
+    3rxW+1eQ2aVKIo4a7PKGjQz5RVIVyzqTUvSZoMTbkAxlSIbO5YfJpTnl3tFcOB6y
+    QMxqQPW/pl6Ni3EmRJdsRM5MsPBRZOfrXxOCdvXu1TWOS1S1TrvEr/TyL9eh2WCd
+    CGzpWgdO4KHce7vs7pECQQDv6DGoG5lHnvbvj9qSJb9K5ebRJc8S+LI7Uy5JHC0j
+    zsHTYPSqBXwPVQdGbgCEycnwwKzXzT2QxAQmJBQKun2ZAkEA2W3aeAE7Xi6zo2eG
+    4Cx4UNMHMIdfBRS7VgoekwybGmcapqV0aBew5kHeWAmxP1WUZ/dgZh2QtM1VuiBA
+    qUqkHwJBAOJLCRvi/JB8N7z82lTk2i3R8gjyOwNQJv6ilZRMyZ9vFZFHcUE27zCf
+    Kb+bX03h8WPwupjMdfgpjShU+7qq8nECQQDBrmyc16QVyo40sgTgblyiysitvviy
+    ovwZsZv4q5MCmvOPnPUrwGbRRb2VONUOMOKpFiBl9lIv7HU//nj7FMVLAkBjUXED
+    83dA8JcKM+HlioXEAxCzZVVhN+D63QwRwkN08xAPklfqDkcqccWDaZm2hdCtaYlK
+    funwYkrzI1OikQSs
+    -----END PRIVATE KEY-----
+    EOF
+    assert_equal pem, rsa1024.private_to_pem
+    assert_same_rsa rsa1024, OpenSSL::PKey.read(pem)
+  end
+
+  def test_private_encoding_encrypted
+    rsa1024 = Fixtures.pkey("rsa1024")
+    encoded = rsa1024.private_to_der("aes-128-cbc", "abcdef")
+    asn1 = OpenSSL::ASN1.decode(encoded) # PKCS #8 EncryptedPrivateKeyInfo
+    assert_kind_of OpenSSL::ASN1::Sequence, asn1
+    assert_equal 2, asn1.value.size
+    assert_not_equal rsa1024.private_to_der, encoded
+    assert_same_rsa rsa1024, OpenSSL::PKey.read(encoded, "abcdef")
+    assert_same_rsa rsa1024, OpenSSL::PKey.read(encoded) { "abcdef" }
+    assert_raise(OpenSSL::PKey::PKeyError) { OpenSSL::PKey.read(encoded, "abcxyz") }
+
+    encoded = rsa1024.private_to_pem("aes-128-cbc", "abcdef")
+    assert_match (/BEGIN ENCRYPTED PRIVATE KEY/), encoded.lines[0]
+    assert_same_rsa rsa1024, OpenSSL::PKey.read(encoded, "abcdef")
+
+    # certtool --load-privkey=test/fixtures/pkey/rsa1024.pem --to-p8 --password=abcdef
+    pem = <<~EOF
+    -----BEGIN ENCRYPTED PRIVATE KEY-----
+    MIICojAcBgoqhkiG9w0BDAEDMA4ECLqajUdSNfzwAgIEkQSCAoCDWhxr1HUrKLXA
+    FsFGGQfPT0aKH4gZipaSXXQRl0KwifHwHoDtfo/mAkJVZMnUVOm1AQ4LTFS3EdTy
+    JUwICGEQHb7QAiokIRoi0K2yHhOxVO8qgbnWuisWpiT6Ru1jCqTs/wcqlqF7z2jM
+    oXDk/vuekKst1DDXDcHrzhDkwhCQWj6jt1r2Vwaryy0FyeqsWAgBDiK2LsnCgkGD
+    21uhNZ/iWMG6tvY9hB8MDdiBJ41YdSG/AKLulAxQ1ibJz0Tasu66TmwFvWhBlME+
+    QbqfgmkgWg5buu53SvDfCA47zXihclbtdfW+U3CJ9OJkx0535TVdZbuC1QgKXvG7
+    4iKGFRMWYJqZvZM3GL4xbC75AxjXZsdCfV81VjZxjeU6ung/NRzCuCUcmBOQzo1D
+    Vv6COwAa6ttQWM0Ti8oIQHdu5Qi+nuOEHDLxCxD962M37H99sEO5cESjmrGVxhEo
+    373L4+11geGSCajdp0yiAGnXQfwaKta8cL693bRObN+b1Y+vqtDKH26N9a4R3qgg
+    2XwgQ5GH5CODoXZpi0wxncXO+3YuuhGeArtzKSXLNxHzIMlY7wZX+0e9UU03zfV/
+    aOe4/q5DpkNxgHePt0oEpamSKY5W3jzVi1dlFWsRjud1p/Grt2zjSWTYClBlJqG1
+    A/3IeDZCu+acaePJjFyv5dFffIj2l4bAYB+LFrZlSu3F/EimO/dCDWJ9JGlMK0aF
+    l9brh7786Mo+YfyklaqMMEHBbbR2Es7PR6Gt7lrcIXmzy9XSsxT6IiD1rG9KKR3i
+    CQxTup6JAx9w1q+adL+Ypikoy3gGD/ccUY6TtPoCmkQwSCS+JqQnFlCiThDJbu+V
+    eqqUNkZq
+    -----END ENCRYPTED PRIVATE KEY-----
+    EOF
+    assert_same_rsa rsa1024, OpenSSL::PKey.read(pem, "abcdef")
+  end
+
+  def test_public_encoding
+    rsa1024 = Fixtures.pkey("rsa1024")
+    assert_equal dup_public(rsa1024).to_der, rsa1024.public_to_der
+    assert_equal dup_public(rsa1024).to_pem, rsa1024.public_to_pem
+  end
+
   def test_dup
     key = Fixtures.pkey("rsa1024")
     key2 = key.dup