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-rw-r--r--gpxe/src/crypto/axtls_aes.c153
1 files changed, 133 insertions, 20 deletions
diff --git a/gpxe/src/crypto/axtls_aes.c b/gpxe/src/crypto/axtls_aes.c
index ac7e921d..51e1924e 100644
--- a/gpxe/src/crypto/axtls_aes.c
+++ b/gpxe/src/crypto/axtls_aes.c
@@ -1,12 +1,58 @@
-#include "crypto/axtls/crypto.h"
+/*
+ * Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
#include <string.h>
#include <errno.h>
+#include <byteswap.h>
#include <gpxe/crypto.h>
+#include <gpxe/cbc.h>
#include <gpxe/aes.h>
+#include "crypto/axtls/crypto.h"
+
+/** @file
+ *
+ * AES algorithm
+ *
+ */
+
+/** Basic AES blocksize */
+#define AES_BLOCKSIZE 16
+
+/** AES context */
+struct aes_context {
+ /** AES context for AXTLS */
+ AES_CTX axtls_ctx;
+ /** Cipher is being used for decrypting */
+ int decrypting;
+};
+/**
+ * Set key
+ *
+ * @v ctx Context
+ * @v key Key
+ * @v keylen Key length
+ * @ret rc Return status code
+ */
static int aes_setkey ( void *ctx, const void *key, size_t keylen ) {
- AES_CTX *aesctx = ctx;
+ struct aes_context *aes_ctx = ctx;
AES_MODE mode;
+ void *iv;
switch ( keylen ) {
case ( 128 / 8 ):
@@ -19,36 +65,103 @@ static int aes_setkey ( void *ctx, const void *key, size_t keylen ) {
return -EINVAL;
}
- AES_set_key ( aesctx, key, aesctx->iv, mode );
+ /* IV is not a relevant concept at this stage; use a dummy
+ * value that will have no side-effects.
+ */
+ iv = &aes_ctx->axtls_ctx.iv;
+
+ AES_set_key ( &aes_ctx->axtls_ctx, key, iv, mode );
+
+ aes_ctx->decrypting = 0;
+
return 0;
}
-static void aes_setiv ( void *ctx, const void *iv ) {
- AES_CTX *aesctx = ctx;
+/**
+ * Set initialisation vector
+ *
+ * @v ctx Context
+ * @v iv Initialisation vector
+ */
+static void aes_setiv ( void *ctx __unused, const void *iv __unused ) {
+ /* Nothing to do */
+}
- memcpy ( aesctx->iv, iv, sizeof ( aesctx->iv ) );
+/**
+ * Call AXTLS' AES_encrypt() or AES_decrypt() functions
+ *
+ * @v axtls_ctx AXTLS AES context
+ * @v src Data to process
+ * @v dst Buffer for output
+ * @v func AXTLS AES function to call
+ */
+static void aes_call_axtls ( AES_CTX *axtls_ctx, const void *src, void *dst,
+ void ( * func ) ( const AES_CTX *axtls_ctx,
+ uint32_t *data ) ){
+ const uint32_t *srcl = src;
+ uint32_t *dstl = dst;
+ unsigned int i;
+
+ /* AXTLS' AES_encrypt() and AES_decrypt() functions both
+ * expect to deal with an array of four dwords in host-endian
+ * order.
+ */
+ for ( i = 0 ; i < 4 ; i++ )
+ dstl[i] = ntohl ( srcl[i] );
+ func ( axtls_ctx, dstl );
+ for ( i = 0 ; i < 4 ; i++ )
+ dstl[i] = htonl ( dstl[i] );
}
-static void aes_encrypt ( void *ctx, const void *data, void *dst,
+/**
+ * Encrypt data
+ *
+ * @v ctx Context
+ * @v src Data to encrypt
+ * @v dst Buffer for encrypted data
+ * @v len Length of data
+ */
+static void aes_encrypt ( void *ctx, const void *src, void *dst,
size_t len ) {
- AES_CTX *aesctx = ctx;
+ struct aes_context *aes_ctx = ctx;
- AES_cbc_encrypt ( aesctx, data, dst, len );
+ assert ( len == AES_BLOCKSIZE );
+ if ( aes_ctx->decrypting )
+ assert ( 0 );
+ aes_call_axtls ( &aes_ctx->axtls_ctx, src, dst, AES_encrypt );
}
-static void aes_decrypt ( void *ctx, const void *data, void *dst,
+/**
+ * Decrypt data
+ *
+ * @v ctx Context
+ * @v src Data to decrypt
+ * @v dst Buffer for decrypted data
+ * @v len Length of data
+ */
+static void aes_decrypt ( void *ctx, const void *src, void *dst,
size_t len ) {
- AES_CTX *aesctx = ctx;
+ struct aes_context *aes_ctx = ctx;
- AES_cbc_decrypt ( aesctx, data, dst, len );
+ assert ( len == AES_BLOCKSIZE );
+ if ( ! aes_ctx->decrypting ) {
+ AES_convert_key ( &aes_ctx->axtls_ctx );
+ aes_ctx->decrypting = 1;
+ }
+ aes_call_axtls ( &aes_ctx->axtls_ctx, src, dst, AES_decrypt );
}
-struct crypto_algorithm aes_algorithm = {
- .name = "aes",
- .ctxsize = sizeof ( AES_CTX ),
- .blocksize = 16,
- .setkey = aes_setkey,
- .setiv = aes_setiv,
- .encode = aes_encrypt,
- .decode = aes_decrypt,
+/** Basic AES algorithm */
+static struct cipher_algorithm aes_algorithm = {
+ .name = "aes",
+ .ctxsize = sizeof ( struct aes_context ),
+ .blocksize = AES_BLOCKSIZE,
+ .setkey = aes_setkey,
+ .setiv = aes_setiv,
+ .encrypt = aes_encrypt,
+ .decrypt = aes_decrypt,
};
+
+/* AES with cipher-block chaining */
+CBC_CIPHER ( aes_cbc, aes_cbc_algorithm,
+ aes_algorithm, struct aes_context, AES_BLOCKSIZE );