diff options
Diffstat (limited to 'contrib/syslinux-4.02/gpxe/src/crypto/cbc.c')
-rw-r--r-- | contrib/syslinux-4.02/gpxe/src/crypto/cbc.c | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/contrib/syslinux-4.02/gpxe/src/crypto/cbc.c b/contrib/syslinux-4.02/gpxe/src/crypto/cbc.c new file mode 100644 index 0000000..1710203 --- /dev/null +++ b/contrib/syslinux-4.02/gpxe/src/crypto/cbc.c @@ -0,0 +1,101 @@ +/* + * 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. + */ + +FILE_LICENCE ( GPL2_OR_LATER ); + +#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 raw_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 *raw_cipher, void *cbc_ctx ) { + size_t blocksize = raw_cipher->blocksize; + + assert ( ( len % blocksize ) == 0 ); + + while ( len ) { + cbc_xor ( src, cbc_ctx, blocksize ); + cipher_encrypt ( raw_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 raw_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 *raw_cipher, void *cbc_ctx ) { + size_t blocksize = raw_cipher->blocksize; + + assert ( ( len % blocksize ) == 0 ); + + while ( len ) { + cipher_decrypt ( raw_cipher, ctx, src, dst, blocksize ); + cbc_xor ( cbc_ctx, dst, blocksize ); + memcpy ( cbc_ctx, src, blocksize ); + dst += blocksize; + src += blocksize; + len -= blocksize; + } +} |