[crypto] Add our own general-purpose cipher-block chaining routines

diff --git a/src/crypto/axtls/aes.c b/src/crypto/axtls/aes.c
index 9154a51..0c0d724 100644 (file)
--- a/src/crypto/axtls/aes.c
+++ b/src/crypto/axtls/aes.c
@@ -152,10 +152,6 @@ static const unsigned char Rcon[30]=
        0xb3,0x7d,0xfa,0xef,0xc5,0x91,
 };
 
-/* ----- static functions ----- */
-static void AES_encrypt(const AES_CTX *ctx, uint32_t *data);
-static void AES_decrypt(const AES_CTX *ctx, uint32_t *data);
-
 /* Perform doubling in Galois Field GF(2^8) using the irreducible polynomial
    x^8+x^4+x^3+x+1 */
 static unsigned char AES_xtime(uint32_t x)
@@ -257,6 +253,7 @@ void AES_convert_key(AES_CTX *ctx)
     }
 }
 
+#if 0
 /**
  * Encrypt a byte sequence (with a block size 16) using the AES cipher.
  */
@@ -358,11 +355,12 @@ void AES_cbc_decrypt(AES_CTX *ctx, const uint8_t *msg, uint8_t *out, int length)
     l2n(xor2, iv);
     l2n(xor3, iv);
 }
+#endif
 
 /**
  * Encrypt a single block (16 bytes) of data
  */
-static void AES_encrypt(const AES_CTX *ctx, uint32_t *data)
+void AES_encrypt(const AES_CTX *ctx, uint32_t *data)
 {
     /* To make this code smaller, generate the sbox entries on the fly.
      * This will have a really heavy effect upon performance.
@@ -418,7 +416,7 @@ static void AES_encrypt(const AES_CTX *ctx, uint32_t *data)
 /**
  * Decrypt a single block (16 bytes) of data
  */
-static void AES_decrypt(const AES_CTX *ctx, uint32_t *data)
+void AES_decrypt(const AES_CTX *ctx, uint32_t *data)
 { 
     uint32_t tmp[4];
     uint32_t xt0,xt1,xt2,xt3,xt4,xt5,xt6;

diff --git a/src/crypto/axtls/crypto.h b/src/crypto/axtls/crypto.h
index de1dbeb..12acb27 100644 (file)
--- a/src/crypto/axtls/crypto.h
+++ b/src/crypto/axtls/crypto.h
@@ -55,6 +55,8 @@ void AES_cbc_encrypt(AES_CTX *ctx, const uint8_t *msg,
         uint8_t *out, int length);
 void AES_cbc_decrypt(AES_CTX *ks, const uint8_t *in, uint8_t *out, int length);
 void AES_convert_key(AES_CTX *ctx);
+void AES_encrypt(const AES_CTX *ctx, uint32_t *data);
+void AES_decrypt(const AES_CTX *ctx, uint32_t *data);
 
 /**************************************************************************
  * RC4 declarations 

diff --git a/src/crypto/axtls_aes.c b/src/crypto/axtls_aes.c
index a19ad3c..04d274d 100644 (file)
--- a/src/crypto/axtls_aes.c
+++ b/src/crypto/axtls_aes.c
@@ -1,17 +1,65 @@
-#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"
 
-struct aes_cbc_context {
-       AES_CTX ctx;
+/** @file
+ *
+ * AES algorithm
+ *
+ */
+
+/** Basic AES blocksize */
+#define AES_BLOCKSIZE 16
+
+/****************************************************************************
+ *
+ * Basic AES algorithm (independent of mode of operation)
+ *
+ ****************************************************************************
+ */
+
+/** AES context */
+struct aes_context {
+       /** AES context for AXTLS */
+       AES_CTX axtls_ctx;
+       /** Cipher is being used for decrypting */
        int decrypting;
 };
 
-static int aes_cbc_setkey ( void *ctx, const void *key, size_t keylen ) {
-       struct aes_cbc_context *aesctx = ctx;
+/**
+ * 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 ) {
+       struct aes_context *aes_ctx = ctx;
        AES_MODE mode;
+       void *iv;
 
        switch ( keylen ) {
        case ( 128 / 8 ):
@@ -24,45 +72,182 @@ static int aes_cbc_setkey ( void *ctx, const void *key, size_t keylen ) {
                return -EINVAL;
        }
 
-       AES_set_key ( &aesctx->ctx, key, aesctx->ctx.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 );
 
-       aesctx->decrypting = 0;
+       aes_ctx->decrypting = 0;
 
        return 0;
 }
 
-static void aes_cbc_setiv ( void *ctx, const void *iv ) {
-       struct aes_cbc_context *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->ctx.iv, iv, sizeof ( aesctx->ctx.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_cbc_encrypt ( void *ctx, const void *data, void *dst,
-                             size_t len ) {
-       struct aes_cbc_context *aesctx = ctx;
+/**
+ * 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 ) {
+       struct aes_context *aes_ctx = ctx;
 
-       if ( aesctx->decrypting )
+       assert ( len == AES_BLOCKSIZE );
+       if ( aes_ctx->decrypting )
                assert ( 0 );
+       aes_call_axtls ( &aes_ctx->axtls_ctx, src, dst, AES_encrypt );
+}
+
+/**
+ * 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 ) {
+       struct aes_context *aes_ctx = ctx;
+
+       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 );
+}
+
+/** 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)
+ *
+ ****************************************************************************
+ */
+
+/** AES with CBC context */
+struct aes_cbc_context {
+       /** AES context */
+       struct aes_context aes_ctx;
+       /** CBC context */
+       uint8_t cbc_ctx[AES_BLOCKSIZE];
+};
+
+/**
+ * Set key
+ *
+ * @v ctx              Context
+ * @v key              Key
+ * @v keylen           Key length
+ * @ret rc             Return status code
+ */
+static int aes_cbc_setkey ( void *ctx, const void *key, size_t keylen ) {
+       struct aes_cbc_context *aes_cbc_ctx = ctx;
 
-       AES_cbc_encrypt ( &aesctx->ctx, data, dst, len );
+       return cbc_setkey ( ctx, key, keylen, &aes_algorithm,
+                           &aes_cbc_ctx->cbc_ctx );
 }
 
-static void aes_cbc_decrypt ( void *ctx, const void *data, void *dst,
+/**
+ * Set initialisation vector
+ *
+ * @v ctx              Context
+ * @v iv               Initialisation vector
+ */
+static void aes_cbc_setiv ( void *ctx, const void *iv ) {
+       struct aes_cbc_context *aes_cbc_ctx = ctx;
+
+       cbc_setiv ( ctx, iv, &aes_algorithm, &aes_cbc_ctx->cbc_ctx );
+}
+
+/**
+ * Encrypt data
+ *
+ * @v ctx              Context
+ * @v src              Data to encrypt
+ * @v dst              Buffer for encrypted data
+ * @v len              Length of data
+ */
+static void aes_cbc_encrypt ( void *ctx, const void *src, void *dst,
                              size_t len ) {
-       struct aes_cbc_context *aesctx = ctx;
+       struct aes_cbc_context *aes_cbc_ctx = ctx;
 
-       if ( ! aesctx->decrypting ) {
-               AES_convert_key ( &aesctx->ctx );
-               aesctx->decrypting = 1;
-       }
+       cbc_encrypt ( &aes_cbc_ctx->aes_ctx, src, dst, len,
+                     &aes_algorithm, &aes_cbc_ctx->cbc_ctx );
+}
+
+/**
+ * Decrypt data
+ *
+ * @v ctx              Context
+ * @v src              Data to decrypt
+ * @v dst              Buffer for decrypted data
+ * @v len              Length of data
+ */
+static void aes_cbc_decrypt ( void *ctx, const void *src, void *dst,
+                             size_t len ) {
+       struct aes_cbc_context *aes_cbc_ctx = ctx;
 
-       AES_cbc_decrypt ( &aesctx->ctx, data, dst, len );
+       cbc_decrypt ( &aes_cbc_ctx->aes_ctx, src, dst, len,
+                     &aes_algorithm, &aes_cbc_ctx->cbc_ctx );
 }
 
+/* AES with cipher-block chaining */
 struct cipher_algorithm aes_cbc_algorithm = {
        .name           = "aes_cbc",
        .ctxsize        = sizeof ( struct aes_cbc_context ),
-       .blocksize      = 16,
+       .blocksize      = AES_BLOCKSIZE,
        .setkey         = aes_cbc_setkey,
        .setiv          = aes_cbc_setiv,
        .encrypt        = aes_cbc_encrypt,

diff --git a/src/crypto/cbc.c b/src/crypto/cbc.c
new file mode 100644 (file)
index 0000000..a25d826
--- /dev/null
+++ b/src/crypto/cbc.c
@@ -0,0 +1,99 @@
+/*
+ * Copyright (C) 2009 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 <assert.h>
+#include <gpxe/crypto.h>
+#include <gpxe/cbc.h>
+
+/** @file
+ *
+ * Cipher-block chaining
+ *
+ */
+
+/**
+ * XOR data blocks
+ *
+ * @v src              Input data
+ * @v dst              Second input data and output data buffer
+ * @v len              Length of data
+ */
+static void cbc_xor ( const void *src, void *dst, size_t len ) {
+       const uint32_t *srcl = src;
+       uint32_t *dstl = dst;
+       unsigned int i;
+
+       /* Assume that block sizes will always be dword-aligned, for speed */
+       assert ( ( len % sizeof ( *srcl ) ) == 0 );
+
+       for ( i = 0 ; i < ( len / sizeof ( *srcl ) ) ; i++ )
+               dstl[i] ^= srcl[i];
+}
+
+/**
+ * Encrypt data
+ *
+ * @v ctx              Context
+ * @v src              Data to encrypt
+ * @v dst              Buffer for encrypted data
+ * @v len              Length of data
+ * @v cipher           Underlying cipher algorithm
+ * @v cbc_ctx          CBC context
+ */
+void cbc_encrypt ( void *ctx, const void *src, void *dst, size_t len,
+                  struct cipher_algorithm *cipher, void *cbc_ctx ) {
+       size_t blocksize = cipher->blocksize;
+
+       assert ( ( len % blocksize ) == 0 );
+
+       while ( len ) {
+               cbc_xor ( src, cbc_ctx, blocksize );
+               cipher_encrypt ( cipher, ctx, cbc_ctx, dst, blocksize );
+               memcpy ( cbc_ctx, dst, blocksize );
+               dst += blocksize;
+               src += blocksize;
+               len -= blocksize;
+       }
+}
+
+/**
+ * Decrypt data
+ *
+ * @v ctx              Context
+ * @v src              Data to decrypt
+ * @v dst              Buffer for decrypted data
+ * @v len              Length of data
+ * @v cipher           Underlying cipher algorithm
+ * @v cbc_ctx          CBC context
+ */
+void cbc_decrypt ( void *ctx, const void *src, void *dst, size_t len,
+                  struct cipher_algorithm *cipher, void *cbc_ctx ) {
+       size_t blocksize = cipher->blocksize;
+
+       assert ( ( len % blocksize ) == 0 );
+
+       while ( len ) {
+               cipher_decrypt ( cipher, ctx, src, dst, blocksize );
+               cbc_xor ( cbc_ctx, dst, blocksize );
+               memcpy ( cbc_ctx, src, blocksize );
+               dst += blocksize;
+               src += blocksize;
+               len -= blocksize;
+       }
+}

diff --git a/src/include/gpxe/cbc.h b/src/include/gpxe/cbc.h
new file mode 100644 (file)
index 0000000..e2d5776
--- /dev/null
+++ b/src/include/gpxe/cbc.h
@@ -0,0 +1,50 @@
+#ifndef _GPXE_CBC_H
+#define _GPXE_CBC_H
+
+/** @file
+ *
+ * Cipher-block chaining
+ *
+ */
+
+#include <gpxe/crypto.h>
+
+/**
+ * Set key
+ *
+ * @v ctx              Context
+ * @v key              Key
+ * @v keylen           Key length
+ * @v cipher           Underlying cipher algorithm
+ * @v cbc_ctx          CBC context
+ * @ret rc             Return status code
+ */
+static inline int cbc_setkey ( void *ctx, const void *key, size_t keylen,
+                              struct cipher_algorithm *cipher,
+                              void *cbc_ctx __unused ) {
+
+       return cipher_setkey ( cipher, ctx, key, keylen );
+}
+
+/**
+ * Set initialisation vector
+ *
+ * @v ctx              Context
+ * @v iv               Initialisation vector
+ * @v cipher           Underlying cipher algorithm
+ * @v cbc_ctx          CBC context
+ */
+static inline void cbc_setiv ( void *ctx __unused, const void *iv,
+                              struct cipher_algorithm *cipher,
+                              void *cbc_ctx ) {
+       memcpy ( cbc_ctx, iv, cipher->blocksize );
+}
+
+extern void cbc_encrypt ( void *ctx, const void *src, void *dst,
+                         size_t len, struct cipher_algorithm *cipher,
+                         void *cbc_ctx );
+extern void cbc_decrypt ( void *ctx, const void *src, void *dst,
+                         size_t len, struct cipher_algorithm *cipher,
+                         void *cbc_ctx );
+
+#endif /* _GPXE_CBC_H */