1 files changed, 97 insertions, 0 deletions
diff --git a/contrib/bearssl/src/x509/encode_rsa_pk8der.c b/contrib/bearssl/src/x509/encode_rsa_pk8der.c
new file mode 100644
index 000000000000..c053503d361f
--- /dev/null
+++ b/contrib/bearssl/src/x509/encode_rsa_pk8der.c
@@ -0,0 +1,97 @@
+/*
+ * Copyright (c) 2018 Thomas Pornin <pornin@bolet.org>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining 
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be 
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include "inner.h"
+
+/* see bearssl_x509.h */
+size_t
+br_encode_rsa_pkcs8_der(void *dest, const br_rsa_private_key *sk,
+	const br_rsa_public_key *pk, const void *d, size_t dlen)
+{
+	/*
+	 * ASN.1 format:
+	 *
+	 *   OneAsymmetricKey ::= SEQUENCE {
+	 *     version                   Version,
+	 *     privateKeyAlgorithm       PrivateKeyAlgorithmIdentifier,
+	 *     privateKey                PrivateKey,
+	 *     attributes            [0] Attributes OPTIONAL,
+	 *     ...,
+	 *     [[2: publicKey        [1] PublicKey OPTIONAL ]],
+	 *     ...
+	 *   }
+	 *
+	 * We don't include attributes or public key. The 'version' field
+	 * is an INTEGER that we will set to 0 (meaning 'v1', compatible
+	 * with previous versions of PKCS#8). The 'privateKeyAlgorithm'
+	 * structure is an AlgorithmIdentifier whose OID should be
+	 * rsaEncryption, with NULL parameters. The 'privateKey' is an
+	 * OCTET STRING, whose value is the "raw DER" encoding of the
+	 * key pair.
+	 *
+	 * Since the private key value comes last, this function really
+	 * adds a header, which is mostly fixed (only some lengths have
+	 * to be modified.
+	 */
+
+	/*
+	 * Concatenation of:
+	 *  - DER encoding of an INTEGER of value 0 (the 'version' field)
+	 *  - DER encoding of a PrivateKeyAlgorithmIdentifier that uses
+	 *    the rsaEncryption OID, and NULL parameters
+	 *  - An OCTET STRING tag
+	 */
+	static const unsigned char PK8_HEAD[] = {
+		0x02, 0x01, 0x00,
+		0x30, 0x0d, 0x06, 0x09, 0x2a, 0x86, 0x48, 0x86,
+		0xf7, 0x0d, 0x01, 0x01, 0x01, 0x05, 0x00,
+		0x04
+	};
+
+	size_t len_raw, len_seq;
+
+	len_raw = br_encode_rsa_raw_der(NULL, sk, pk, d, dlen);
+	len_seq = (sizeof PK8_HEAD) + len_of_len(len_raw) + len_raw;
+	if (dest == NULL) {
+		return 1 + len_of_len(len_seq) + len_seq;
+	} else {
+		unsigned char *buf;
+		size_t lenlen;
+
+		buf = dest;
+		*buf ++ = 0x30;  /* SEQUENCE tag */
+		lenlen = br_asn1_encode_length(buf, len_seq);
+		buf += lenlen;
+
+		/* version, privateKeyAlgorithm, privateKey tag */
+		memcpy(buf, PK8_HEAD, sizeof PK8_HEAD);
+		buf += sizeof PK8_HEAD;
+
+		/* privateKey */
+		buf += br_asn1_encode_length(buf, len_raw);
+		br_encode_rsa_raw_der(buf, sk, pk, d, dlen);
+
+		return 1 + lenlen + len_seq;
+	}
+}