From: Tobias Brunner <tobias@strongswan.org>
Date: Wed, 23 Oct 2024 15:14:56 +0000 (+0200)
Subject: botan: Add support for AES in ECB mode to support DRBG_CTR_AES
X-Git-Tag: 6.0.0rc1~20
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ebdaab6861c8a948131c0d38094ebc415999c248;p=thirdparty%2Fstrongswan.git

botan: Add support for AES in ECB mode to support DRBG_CTR_AES

This DRBG is used to test ML-KEM.
---

diff --git a/src/libstrongswan/plugins/botan/botan_crypter.c b/src/libstrongswan/plugins/botan/botan_crypter.c
index d3ccb4bb9b..708c7727ad 100644
--- a/src/libstrongswan/plugins/botan/botan_crypter.c
+++ b/src/libstrongswan/plugins/botan/botan_crypter.c
@@ -1,4 +1,6 @@
 /*
+ * Copyright (C) 2024 Tobias Brunner
+ *
  * Copyright (C) 2018 René Korthaus
  * Copyright (C) 2018 Konstantinos Kolelis
  * Copyright (C) 2018 Tobias Hommel
@@ -48,6 +50,11 @@ struct private_botan_crypter_t {
 	 */
 	chunk_t	key;
 
+	/**
+	 * Algorithm identifier
+	 */
+	encryption_algorithm_t alg;
+
 	/**
 	 * The cipher name
 	 */
@@ -55,27 +62,48 @@ struct private_botan_crypter_t {
 };
 
 /**
- * Do the actual en/decryption
+ * Do the actual en/decryption in ECB, which requires a separate "raw" API.
  */
-static bool crypt(private_botan_crypter_t *this, chunk_t data, chunk_t iv,
-				  chunk_t *dst, uint32_t init_flag)
+static bool crypt_ecb(private_botan_crypter_t *this, uint8_t *in, uint8_t *out,
+					  size_t len, uint32_t init_flag)
 {
-	botan_cipher_t cipher;
-	size_t output_written = 0;
-	size_t input_consumed = 0;
-	uint8_t *in, *out;
+	botan_block_cipher_t cipher;
+	size_t blocks = len / AES_BLOCK_SIZE;
 	bool success = FALSE;
 
-	in = data.ptr;
-	if (dst)
+	if (len % AES_BLOCK_SIZE)
 	{
-		*dst = chunk_alloc(data.len);
-		out = dst->ptr;
+		return FALSE;
+	}
+
+	if (botan_block_cipher_init(&cipher, this->cipher_name) ||
+		botan_block_cipher_set_key(cipher, this->key.ptr, this->key.len))
+	{
+		return FALSE;
+	}
+
+	if (init_flag == BOTAN_CIPHER_INIT_FLAG_ENCRYPT)
+	{
+		success = !botan_block_cipher_encrypt_blocks(cipher, in, out, blocks);
 	}
 	else
 	{
-		out = data.ptr;
+		success = !botan_block_cipher_decrypt_blocks(cipher, in, out, blocks);
 	}
+	botan_block_cipher_destroy(cipher);
+	return success;
+}
+
+/**
+ * Do the actual en/decryption for modes other than ECB.
+ */
+static bool crypt_modes(private_botan_crypter_t *this, chunk_t iv, uint8_t *in,
+						uint8_t *out, size_t len, uint32_t init_flag)
+{
+	botan_cipher_t cipher;
+	size_t output_written = 0;
+	size_t input_consumed = 0;
+	bool success = FALSE;
 
 	if (botan_cipher_init(&cipher, this->cipher_name, init_flag))
 	{
@@ -85,8 +113,7 @@ static bool crypt(private_botan_crypter_t *this, chunk_t data, chunk_t iv,
 	if (!botan_cipher_set_key(cipher, this->key.ptr, this->key.len) &&
 		!botan_cipher_start(cipher, iv.ptr, iv.len) &&
 		!botan_cipher_update(cipher, BOTAN_CIPHER_UPDATE_FLAG_FINAL, out,
-							 data.len, &output_written, in, data.len,
-							 &input_consumed) &&
+							 len, &output_written, in, len, &input_consumed) &&
 		(output_written == input_consumed))
 	{
 		success = TRUE;
@@ -96,13 +123,38 @@ static bool crypt(private_botan_crypter_t *this, chunk_t data, chunk_t iv,
 	return success;
 }
 
+/**
+ * Do the actual en/decryption
+ */
+static bool crypt(private_botan_crypter_t *this, chunk_t data, chunk_t iv,
+				  chunk_t *dst, uint32_t init_flag)
+{
+	uint8_t *in, *out;
+
+	in = data.ptr;
+	if (dst)
+	{
+		*dst = chunk_alloc(data.len);
+		out = dst->ptr;
+	}
+	else
+	{
+		out = data.ptr;
+	}
+
+	if (this->alg == ENCR_AES_ECB)
+	{
+		return crypt_ecb(this, in, out, data.len, init_flag);
+	}
+	return crypt_modes(this, iv, in, out, data.len, init_flag);
+}
+
 METHOD(crypter_t, decrypt, bool,
 	private_botan_crypter_t *this, chunk_t data, chunk_t iv, chunk_t *dst)
 {
 	return crypt(this, data, iv, dst, BOTAN_CIPHER_INIT_FLAG_DECRYPT);
 }
 
-
 METHOD(crypter_t, encrypt, bool,
 	private_botan_crypter_t *this, chunk_t data, chunk_t iv, chunk_t *dst)
 {
@@ -118,7 +170,7 @@ METHOD(crypter_t, get_block_size, size_t,
 METHOD(crypter_t, get_iv_size, size_t,
 	private_botan_crypter_t *this)
 {
-	return AES_BLOCK_SIZE;
+	return this->alg == ENCR_AES_ECB ? 0 : AES_BLOCK_SIZE;
 }
 
 METHOD(crypter_t, get_key_size, size_t,
@@ -161,10 +213,31 @@ botan_crypter_t *botan_crypter_create(encryption_algorithm_t algo,
 				.destroy = _destroy,
 			},
 		},
+		.alg = algo,
 	);
 
 	switch (algo)
 	{
+		case ENCR_AES_ECB:
+			switch (key_size)
+			{
+				case 16:
+					/* AES 128 */
+					this->cipher_name = "AES-128";
+					break;
+				case 24:
+					/* AES-192 */
+					this->cipher_name = "AES-192";
+					break;
+				case 32:
+					/* AES-256 */
+					this->cipher_name = "AES-256";
+					break;
+				default:
+					free(this);
+					return NULL;
+			}
+			break;
 		case ENCR_AES_CBC:
 			switch (key_size)
 			{
diff --git a/src/libstrongswan/plugins/botan/botan_plugin.c b/src/libstrongswan/plugins/botan/botan_plugin.c
index 3fe3297658..30a6dcce68 100644
--- a/src/libstrongswan/plugins/botan/botan_plugin.c
+++ b/src/libstrongswan/plugins/botan/botan_plugin.c
@@ -104,9 +104,11 @@ METHOD(plugin_t, get_features, int,
 #endif
 
 		/* crypters */
-#if defined(BOTAN_HAS_AES) && defined(BOTAN_HAS_MODE_CBC)
+#if defined(BOTAN_HAS_AES)
 		PLUGIN_REGISTER(CRYPTER, botan_crypter_create),
-#ifdef BOTAN_HAS_AES
+			PLUGIN_PROVIDE(CRYPTER, ENCR_AES_ECB, 16),
+			PLUGIN_PROVIDE(CRYPTER, ENCR_AES_ECB, 24),
+			PLUGIN_PROVIDE(CRYPTER, ENCR_AES_ECB, 32),
 	#ifdef BOTAN_HAS_MODE_CBC
 			PLUGIN_PROVIDE(CRYPTER, ENCR_AES_CBC, 16),
 			PLUGIN_PROVIDE(CRYPTER, ENCR_AES_CBC, 24),
@@ -117,7 +119,6 @@ METHOD(plugin_t, get_features, int,
 			PLUGIN_PROVIDE(CRYPTER, ENCR_AES_CFB, 24),
 			PLUGIN_PROVIDE(CRYPTER, ENCR_AES_CFB, 32),
 	#endif
-#endif
 #endif
 
 		/* AEAD */