botan: Encode private keys as PKCS#8

Since we can now parse that encoding directly we can simplify the private
key export and stick to PKCS#8.

src/libstrongswan/plugins/botan/botan_ec_private_key.c

@@ -209,123 +209,11 @@ METHOD(private_key_t, get_fingerprint, bool,
 	return success;
 }
 
-/**
- * Get a field from the private key as chunk
- */
-static bool get_field_chunk(botan_privkey_t key, char *field, chunk_t *out)
-{
-	botan_mp_t val;
-
-	*out = chunk_empty;
-
-	if (botan_mp_init(&val))
-	{
-		return FALSE;
-	}
-
-	if (botan_privkey_get_field(val, key, field) ||
-		botan_mp_num_bytes(val, &out->len))
-	{
-		botan_mp_destroy(val);
-		return FALSE;
-	}
-
-	*out = chunk_alloc(out->len);
-
-	if (botan_mp_to_bin(val, out->ptr))
-	{
-		botan_mp_destroy(val);
-		chunk_free(out);
-		return FALSE;
-	}
-	botan_mp_destroy(val);
-	return TRUE;
-}
-
-/**
- * Encodes the public key as ASN.1 BIT STRING (0x04 || x || y)
- */
-static bool get_pubkey_bitstring(botan_privkey_t key, chunk_t *out)
-{
-	chunk_t p, x, y, pub;
-	size_t len;
-
-	if (!get_field_chunk(key, "p", &p))
-	{
-		return FALSE;
-	}
-	len = p.len;
-	chunk_free(&p);
-
-	if (!get_field_chunk(key, "public_x", &x))
-	{
-		return FALSE;
-	}
-	if (!get_field_chunk(key, "public_y", &y))
-	{
-		chunk_free(&x);
-		return FALSE;
-	}
-
-	pub = chunk_alloca(2 * len);
-	memset(pub.ptr, 0, pub.len);
-	memcpy(pub.ptr + (len - x.len), x.ptr, x.len);
-	memcpy(pub.ptr + len + (len - y.len), y.ptr, y.len);
-	chunk_free(&x);
-	chunk_free(&y);
-
-	*out = asn1_wrap(ASN1_BIT_STRING, "ccc",
-					 /* unused bits in the bit string */
-					 chunk_from_chars(0x00),
-					 /* uncompressed format */
-					 chunk_from_chars(0x04), pub);
-	return TRUE;
-}
-
 METHOD(private_key_t, get_encoding, bool,
 	private_botan_ec_private_key_t *this, cred_encoding_type_t type,
 	chunk_t *encoding)
 {
-	switch (type)
+	return botan_get_privkey_encoding(this->key, type, encoding);
-	{
-		case PRIVKEY_ASN1_DER:
-		case PRIVKEY_PEM:
-		{
-			chunk_t priv, pub;
-			bool success = TRUE;
-
-			if (!get_field_chunk(this->key, "x", &priv))
-			{
-				return FALSE;
-			}
-			if (!get_pubkey_bitstring(this->key, &pub))
-			{
-				chunk_clear(&priv);
-				return FALSE;
-			}
-
-			*encoding = asn1_wrap(ASN1_SEQUENCE, "msmm",
-								  asn1_integer("c", chunk_from_chars(0x01)),
-								  asn1_wrap(ASN1_OCTET_STRING, "s", priv),
-								  asn1_wrap(ASN1_CONTEXT_C_0, "m",
-										asn1_build_known_oid(this->oid)),
-								  asn1_wrap(ASN1_CONTEXT_C_1, "m", pub));
-
-			if (type == PRIVKEY_PEM)
-			{
-				chunk_t asn1_encoding = *encoding;
-
-				success = lib->encoding->encode(lib->encoding, PRIVKEY_PEM,
-												NULL, encoding,
-												CRED_PART_ECDSA_PRIV_ASN1_DER,
-												asn1_encoding, CRED_PART_END);
-				chunk_clear(&asn1_encoding);
-			}
-			return success;
-		}
-		default:
-			return FALSE;
-	}
 }
 
 METHOD(private_key_t, get_ref, private_key_t*,

src/libstrongswan/plugins/botan/botan_rsa_private_key.c

@@ -257,38 +257,7 @@ METHOD(private_key_t, get_encoding, bool,
 	private_botan_rsa_private_key_t *this, cred_encoding_type_t type,
 	chunk_t *encoding)
 {
-	switch (type)
+	return botan_get_privkey_encoding(this->key, type, encoding);
-	{
-		case PRIVKEY_ASN1_DER:
-		case PRIVKEY_PEM:
-		{
-			uint32_t format = BOTAN_PRIVKEY_EXPORT_FLAG_DER;
-			size_t len = 0;
-			bool success = TRUE;
-
-			if (type == PRIVKEY_PEM)
-			{
-				format = BOTAN_PRIVKEY_EXPORT_FLAG_PEM;
-			}
-
-			if (botan_privkey_rsa_get_privkey(this->key, NULL, &len, format)
-				!= BOTAN_FFI_ERROR_INSUFFICIENT_BUFFER_SPACE)
-			{
-				return FALSE;
-			}
-
-			*encoding = chunk_alloc(len);
-			if (botan_privkey_rsa_get_privkey(this->key, encoding->ptr, &len,
-											  format))
-			{
-				chunk_clear(encoding);
-				return FALSE;
-			}
-			return success;
-		}
-		default:
-			return FALSE;
-	}
 }
 
 METHOD(private_key_t, get_ref, private_key_t*,

src/libstrongswan/plugins/botan/botan_util.c

@@ -108,6 +108,39 @@ bool botan_get_encoding(botan_pubkey_t pubkey, cred_encoding_type_t type,
 	return success;
 }
 
+/*
+ * Described in header
+ */
+bool botan_get_privkey_encoding(botan_privkey_t key, cred_encoding_type_t type,
+								chunk_t *encoding)
+{
+	uint32_t format = BOTAN_PRIVKEY_EXPORT_FLAG_DER;
+
+	switch (type)
+	{
+		case PRIVKEY_PEM:
+			format = BOTAN_PRIVKEY_EXPORT_FLAG_PEM;
+			/* fall-through */
+		case PRIVKEY_ASN1_DER:
+			encoding->len = 0;
+			if (botan_privkey_export(key, NULL, &encoding->len, format)
+				!= BOTAN_FFI_ERROR_INSUFFICIENT_BUFFER_SPACE)
+			{
+				return FALSE;
+			}
+			*encoding = chunk_alloc(encoding->len);
+			if (botan_privkey_export(key, encoding->ptr, &encoding->len,
+									 format))
+			{
+				chunk_free(encoding);
+				return FALSE;
+			}
+			return TRUE;
+		default:
+			return FALSE;
+	}
+}
+
 /*
  * Described in header
  */

src/libstrongswan/plugins/botan/botan_util.h

@@ -64,6 +64,17 @@ const char *botan_get_hash(hash_algorithm_t hash);
 bool botan_get_encoding(botan_pubkey_t pubkey, cred_encoding_type_t type,
 						chunk_t *encoding);
 
+/**
+ * Get the encoding of a botan_privkey_t.
+ *
+ * @param key		private key object
+ * @param type		encoding type
+ * @param encoding	allocated encoding
+ * @return			TRUE if encoding successful
+ */
+bool botan_get_privkey_encoding(botan_privkey_t key, cred_encoding_type_t type,
+								chunk_t *encoding);
+
 /**
  * Get the fingerprint of a botan_pubkey_t.
  *