gcrypt: Support RSA OAEP SHA1 encryption/decryption

src/libstrongswan/plugins/gcrypt/gcrypt_plugin.c

@@ -135,6 +135,7 @@ METHOD(plugin_t, get_features, int,
 		PLUGIN_PROVIDE(PRIVKEY_SIGN, SIGN_RSA_EMSA_PKCS1_SHA1),
 		PLUGIN_PROVIDE(PRIVKEY_SIGN, SIGN_RSA_EMSA_PKCS1_MD5),
 		PLUGIN_PROVIDE(PRIVKEY_DECRYPT, ENCRYPT_RSA_PKCS1),
+		PLUGIN_PROVIDE(PRIVKEY_DECRYPT, ENCRYPT_RSA_OAEP_SHA1),
 		/* signature verification schemes */
 #if GCRYPT_VERSION_NUMBER >= 0x010700
 		PLUGIN_PROVIDE(PUBKEY_VERIFY, SIGN_RSA_EMSA_PSS),
@@ -147,6 +148,7 @@ METHOD(plugin_t, get_features, int,
 		PLUGIN_PROVIDE(PUBKEY_VERIFY, SIGN_RSA_EMSA_PKCS1_SHA1),
 		PLUGIN_PROVIDE(PUBKEY_VERIFY, SIGN_RSA_EMSA_PKCS1_MD5),
 		PLUGIN_PROVIDE(PUBKEY_ENCRYPT, ENCRYPT_RSA_PKCS1),
+		PLUGIN_PROVIDE(PUBKEY_ENCRYPT, ENCRYPT_RSA_OAEP_SHA1),
 		/* random numbers */
 		PLUGIN_REGISTER(RNG, gcrypt_rng_create),
 			PLUGIN_PROVIDE(RNG, RNG_WEAK),

src/libstrongswan/plugins/gcrypt/gcrypt_rsa_private_key.c

@@ -282,49 +282,53 @@ METHOD(private_key_t, decrypt, bool,
 {
 	gcry_error_t err;
 	gcry_sexp_t in, out;
-	chunk_t padded;
+	chunk_t label = chunk_empty, decrypted;
-	u_char *pos = NULL;;
+	u_char *sexp;
 
-	if (scheme != ENCRYPT_RSA_PKCS1)
+	switch (scheme)
 	{
-		DBG1(DBG_LIB, "encryption scheme %N not supported",
+		case ENCRYPT_RSA_PKCS1:
-			 encryption_scheme_names, scheme);
+			sexp = "(enc-val(flags pkcs1)(rsa(a %b)))";
-		return FALSE;
+			break;
+		case ENCRYPT_RSA_OAEP_SHA1:
+			sexp = "(enc-val(flags oaep)(rsa(a %b)))";
+			break;
+		default:
+			DBG1(DBG_LIB, "encryption scheme %N not supported",
+				 encryption_scheme_names, scheme);
+			return FALSE;
 	}
-	err = gcry_sexp_build(&in, NULL, "(enc-val(flags)(rsa(a %b)))",
+
-						  encrypted.len, encrypted.ptr);
+	if (scheme == ENCRYPT_RSA_OAEP_SHA1 && params != NULL)
+	{
+		label = *(chunk_t *)params;
+		if (label.len > 0)
+		{
+			DBG1(DBG_LIB, "RSA OAEP decryption with a label not supported");
+			return FALSE;
+		}
+	}
+
+	err = gcry_sexp_build(&in, NULL, sexp, encrypted.len, encrypted.ptr);
 	if (err)
 	{
 		DBG1(DBG_LIB, "building decryption S-expression failed: %s",
 			 gpg_strerror(err));
 		return FALSE;
 	}
+
 	err = gcry_pk_decrypt(&out, in, this->key);
 	gcry_sexp_release(in);
 	if (err)
 	{
-		DBG1(DBG_LIB, "decrypting pkcs1 data failed: %s", gpg_strerror(err));
+		DBG1(DBG_LIB, "RSA decryption failed: %s", gpg_strerror(err));
 		return FALSE;
 	}
-	padded.ptr = (u_char*)gcry_sexp_nth_data(out, 1, &padded.len);
+
-	/* result is padded, but gcrypt strips leading zero:
+	decrypted.ptr = (u_char*)gcry_sexp_nth_data(out, 1, &decrypted.len);
-	 *  00 | 02 | RANDOM | 00 | DATA */
+	*plain = chunk_clone(decrypted);
-	if (padded.ptr && padded.len > 2 && padded.ptr[0] == 0x02)
-	{
-		pos = memchr(padded.ptr, 0x00, padded.len - 1);
-		if (pos)
-		{
-			pos++;
-			*plain = chunk_clone(chunk_create(
-										pos, padded.len - (pos - padded.ptr)));
-		}
-	}
 	gcry_sexp_release(out);
-	if (!pos)
+
-	{
-		DBG1(DBG_LIB, "decrypted data has invalid pkcs1 padding");
-		return FALSE;
-	}
 	return TRUE;
 }
 

src/libstrongswan/plugins/gcrypt/gcrypt_rsa_public_key.c

@@ -239,36 +239,55 @@ METHOD(public_key_t, encrypt_, bool,
 	private_gcrypt_rsa_public_key_t *this, encryption_scheme_t scheme,
 	void *params, chunk_t plain, chunk_t *encrypted)
 {
-	gcry_sexp_t in, out;
 	gcry_error_t err;
+	gcry_sexp_t in, out;
+	chunk_t label = chunk_empty;
+	u_char *sexp;
 
-	if (scheme != ENCRYPT_RSA_PKCS1)
+	switch (scheme)
 	{
-		DBG1(DBG_LIB, "encryption scheme %N not supported",
+		case ENCRYPT_RSA_PKCS1:
-			 encryption_scheme_names, scheme);
+			sexp = "(data(flags pkcs1)(value %b))";
-		return FALSE;
+			break;
+		case ENCRYPT_RSA_OAEP_SHA1:
+			sexp = "(data(flags oaep)(value %b))";
+			break;
+		default:
+			DBG1(DBG_LIB, "encryption scheme %N not supported",
+				 encryption_scheme_names, scheme);
+			return FALSE;
 	}
-	/* "pkcs1" uses PKCS 1.5 (section 8.1) block type 2 encryption:
+
-	 * 00 | 02 | RANDOM | 00 | DATA */
+	if (scheme == ENCRYPT_RSA_OAEP_SHA1 && params != NULL)
-	err = gcry_sexp_build(&in, NULL, "(data(flags pkcs1)(value %b))",
+	{
-						  plain.len, plain.ptr);
+		label = *(chunk_t *)params;
+		if (label.len > 0)
+		{
+			DBG1(DBG_LIB, "RSA OAEP encryption with a label not supported");
+			return FALSE;
+		}
+	}
+
+	err = gcry_sexp_build(&in, NULL, sexp, plain.len, plain.ptr);
 	if (err)
 	{
 		DBG1(DBG_LIB, "building encryption S-expression failed: %s",
 			 gpg_strerror(err));
 		return FALSE;
 	}
+
 	err = gcry_pk_encrypt(&out, in, this->key);
 	gcry_sexp_release(in);
 	if (err)
 	{
-		DBG1(DBG_LIB, "encrypting data using pkcs1 failed: %s",
+		DBG1(DBG_LIB, "RSA encryption failed: %s", gpg_strerror(err));
-			 gpg_strerror(err));
 		return FALSE;
 	}
+
 	*encrypted = gcrypt_rsa_find_token(out, "a", this->key);
 	gcry_sexp_release(out);
-	return !!encrypted->len;
+
+	return encrypted->len > 0;
 }
 
 METHOD(public_key_t, get_keysize, int,