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Annotation of qemu/roms/ipxe/src/crypto/cbc.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (C) 2009 Michael Brown <[email protected]>.
        !             3:  *
        !             4:  * This program is free software; you can redistribute it and/or
        !             5:  * modify it under the terms of the GNU General Public License as
        !             6:  * published by the Free Software Foundation; either version 2 of the
        !             7:  * License, or any later version.
        !             8:  *
        !             9:  * This program is distributed in the hope that it will be useful, but
        !            10:  * WITHOUT ANY WARRANTY; without even the implied warranty of
        !            11:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
        !            12:  * General Public License for more details.
        !            13:  *
        !            14:  * You should have received a copy of the GNU General Public License
        !            15:  * along with this program; if not, write to the Free Software
        !            16:  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
        !            17:  */
        !            18: 
        !            19: FILE_LICENCE ( GPL2_OR_LATER );
        !            20: 
        !            21: #include <string.h>
        !            22: #include <assert.h>
        !            23: #include <ipxe/crypto.h>
        !            24: #include <ipxe/cbc.h>
        !            25: 
        !            26: /** @file
        !            27:  *
        !            28:  * Cipher-block chaining
        !            29:  *
        !            30:  */
        !            31: 
        !            32: /**
        !            33:  * XOR data blocks
        !            34:  *
        !            35:  * @v src              Input data
        !            36:  * @v dst              Second input data and output data buffer
        !            37:  * @v len              Length of data
        !            38:  */
        !            39: static void cbc_xor ( const void *src, void *dst, size_t len ) {
        !            40:        const uint32_t *srcl = src;
        !            41:        uint32_t *dstl = dst;
        !            42:        unsigned int i;
        !            43: 
        !            44:        /* Assume that block sizes will always be dword-aligned, for speed */
        !            45:        assert ( ( len % sizeof ( *srcl ) ) == 0 );
        !            46: 
        !            47:        for ( i = 0 ; i < ( len / sizeof ( *srcl ) ) ; i++ )
        !            48:                dstl[i] ^= srcl[i];
        !            49: }
        !            50: 
        !            51: /**
        !            52:  * Encrypt data
        !            53:  *
        !            54:  * @v ctx              Context
        !            55:  * @v src              Data to encrypt
        !            56:  * @v dst              Buffer for encrypted data
        !            57:  * @v len              Length of data
        !            58:  * @v raw_cipher       Underlying cipher algorithm
        !            59:  * @v cbc_ctx          CBC context
        !            60:  */
        !            61: void cbc_encrypt ( void *ctx, const void *src, void *dst, size_t len,
        !            62:                   struct cipher_algorithm *raw_cipher, void *cbc_ctx ) {
        !            63:        size_t blocksize = raw_cipher->blocksize;
        !            64: 
        !            65:        assert ( ( len % blocksize ) == 0 );
        !            66: 
        !            67:        while ( len ) {
        !            68:                cbc_xor ( src, cbc_ctx, blocksize );
        !            69:                cipher_encrypt ( raw_cipher, ctx, cbc_ctx, dst, blocksize );
        !            70:                memcpy ( cbc_ctx, dst, blocksize );
        !            71:                dst += blocksize;
        !            72:                src += blocksize;
        !            73:                len -= blocksize;
        !            74:        }
        !            75: }
        !            76: 
        !            77: /**
        !            78:  * Decrypt data
        !            79:  *
        !            80:  * @v ctx              Context
        !            81:  * @v src              Data to decrypt
        !            82:  * @v dst              Buffer for decrypted data
        !            83:  * @v len              Length of data
        !            84:  * @v raw_cipher       Underlying cipher algorithm
        !            85:  * @v cbc_ctx          CBC context
        !            86:  */
        !            87: void cbc_decrypt ( void *ctx, const void *src, void *dst, size_t len,
        !            88:                   struct cipher_algorithm *raw_cipher, void *cbc_ctx ) {
        !            89:        size_t blocksize = raw_cipher->blocksize;
        !            90: 
        !            91:        assert ( ( len % blocksize ) == 0 );
        !            92: 
        !            93:        while ( len ) {
        !            94:                cipher_decrypt ( raw_cipher, ctx, src, dst, blocksize );
        !            95:                cbc_xor ( cbc_ctx, dst, blocksize );
        !            96:                memcpy ( cbc_ctx, src, blocksize );
        !            97:                dst += blocksize;
        !            98:                src += blocksize;
        !            99:                len -= blocksize;
        !           100:        }
        !           101: }

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