aes_modes.c

AES源码

/*
 ---------------------------------------------------------------------------
 Copyright (c) 1998-2006, Brian Gladman, Worcester, UK. All rights reserved.

 LICENSE TERMS

 The free distribution and use of this software in both source and binary
 form is allowed (with or without changes) provided that:

   1. distributions of this source code include the above copyright
      notice, this list of conditions and the following disclaimer;

   2. distributions in binary form include the above copyright
      notice, this list of conditions and the following disclaimer
      in the documentation and/or other associated materials;

   3. the copyright holder's name is not used to endorse products
      built using this software without specific written permission.

 ALTERNATIVELY, provided that this notice is retained in full, this product
 may be distributed under the terms of the GNU General Public License (GPL),
 in which case the provisions of the GPL apply INSTEAD OF those given above.

 DISCLAIMER

 This software is provided 'as is' with no explicit or implied warranties
 in respect of its properties, including, but not limited to, correctness
 and/or fitness for purpose.
 ---------------------------------------------------------------------------
 Issue 16/04/2007

 These subroutines implement multiple block AES modes for ECB, CBC, CFB,
 OFB and CTR encryption,  The code provides support for the VIA Advanced
 Cryptography Engine (ACE).

 NOTE: In the following subroutines, the AES contexts (ctx) must be
 16 byte aligned if VIA ACE is being used
*/

#include <string.h>
#include <assert.h>

#include "aesopt.h"

#if defined( AES_MODES )
#if defined(__cplusplus)
extern "C"
{
#endif

#if defined( _MSC_VER ) && ( _MSC_VER > 800 )
#pragma intrinsic(memcpy)
#define in_line __inline
#else
#define in_line
#endif

#define BFR_BLOCKS      8

/* These values are used to detect long word alignment in order to */
/* speed up some buffer operations. This facility may not work on  */
/* some machines so this define can be commented out if necessary  */

#define FAST_BUFFER_OPERATIONS

#define lp32(x)         ((uint_32t*)(x))

#if defined( USE_VIA_ACE_IF_PRESENT )

#include "aes_via_ace.h"

#pragma pack(16)

aligned_array(unsigned long,    enc_gen_table, 12, 16) =    NEH_ENC_GEN_DATA;
aligned_array(unsigned long,   enc_load_table, 12, 16) =   NEH_ENC_LOAD_DATA;
aligned_array(unsigned long, enc_hybrid_table, 12, 16) = NEH_ENC_HYBRID_DATA;
aligned_array(unsigned long,    dec_gen_table, 12, 16) =    NEH_DEC_GEN_DATA;
aligned_array(unsigned long,   dec_load_table, 12, 16) =   NEH_DEC_LOAD_DATA;
aligned_array(unsigned long, dec_hybrid_table, 12, 16) = NEH_DEC_HYBRID_DATA;

/* NOTE: These control word macros must only be used after  */
/* a key has been set up because they depend on key size    */

#if NEH_KEY_TYPE == NEH_LOAD
#define kd_adr(c)   ((uint_8t*)(c)->ks)
#elif NEH_KEY_TYPE == NEH_GENERATE
#define kd_adr(c)   ((uint_8t*)(c)->ks + (c)->inf.b[0])
#else
#define kd_adr(c)   ((uint_8t*)(c)->ks + ((c)->inf.b[0] == 160 ? 160 : 0))
#endif

#else

#define aligned_array(type, name, no, stride) type name[no]
#define aligned_auto(type, name, no, stride)  type name[no]

#endif

#if defined( _MSC_VER ) && _MSC_VER > 1200

#define via_cwd(cwd, ty, dir, len) \
    unsigned long* cwd = (dir##_##ty##_table + ((len - 128) >> 4))

#else

#define via_cwd(cwd, ty, dir, len)              \
    aligned_auto(unsigned long, cwd, 4, 16);    \
    cwd[1] = cwd[2] = cwd[3] = 0;               \
    cwd[0] = neh_##dir##_##ty##_key(len)

#endif

/* test the code for detecting and setting pointer alignment */

AES_RETURN aes_test_alignment_detection(unsigned int n)	/* 4 <= n <= 16 */
{	uint_8t	p[16];
	uint_32t i, count_eq = 0, count_neq = 0;

	if(n < 4 || n > 16)
		return EXIT_FAILURE;

	for(i = 0; i < n; ++i)
	{
		uint_8t *qf = ALIGN_FLOOR(p + i, n),
				*qh =  ALIGN_CEIL(p + i, n);
		
		if(qh == qf)
			++count_eq;
		else if(qh == qf + n)
			++count_neq;
		else
			return EXIT_FAILURE;
	}
	return (count_eq != 1 || count_neq != n - 1 ? EXIT_FAILURE : EXIT_SUCCESS);
}

AES_RETURN aes_mode_reset(aes_encrypt_ctx ctx[1])
{
    ctx->inf.b[2] = 0;
    return EXIT_SUCCESS;
}

AES_RETURN aes_ecb_encrypt(const unsigned char *ibuf, unsigned char *obuf,
                    int len, const aes_encrypt_ctx ctx[1])
{   int nb = len >> 4;

    if(len & (AES_BLOCK_SIZE - 1))
        return EXIT_FAILURE;

#if defined( USE_VIA_ACE_IF_PRESENT )

    if(ctx->inf.b[1] == 0xff)
    {   uint_8t *ksp = (uint_8t*)(ctx->ks);
        via_cwd(cwd, hybrid, enc, 2 * ctx->inf.b[0] - 192);

        if(ALIGN_OFFSET( ctx, 16 ))
            return EXIT_FAILURE;

        if(!ALIGN_OFFSET( ibuf, 16 ) && !ALIGN_OFFSET( obuf, 16 ))
        {
            via_ecb_op5(ksp,cwd,ibuf,obuf,nb);
        }
        else
        {   aligned_auto(uint_8t, buf, BFR_BLOCKS * AES_BLOCK_SIZE, 16);
            uint_8t *ip, *op;

            while(nb)
            {
                int m = (nb > BFR_BLOCKS ? BFR_BLOCKS : nb);

                ip = (ALIGN_OFFSET( ibuf, 16 ) ? buf : (uint_8t*)ibuf);
                op = (ALIGN_OFFSET( obuf, 16 ) ? buf : obuf);

                if(ip != ibuf)
                    memcpy(buf, ibuf, m * AES_BLOCK_SIZE);

                via_ecb_op5(ksp,cwd,ip,op,m);

                if(op != obuf)
                    memcpy(obuf, buf, m * AES_BLOCK_SIZE);

                ibuf += m * AES_BLOCK_SIZE;
                obuf += m * AES_BLOCK_SIZE;
                nb -= m;
            }
        }

        return EXIT_SUCCESS;
    }

#endif

#if !defined( ASSUME_VIA_ACE_PRESENT )
    while(nb--)
    {
        if(aes_encrypt(ibuf, obuf, ctx) != EXIT_SUCCESS)
			return EXIT_FAILURE;
        ibuf += AES_BLOCK_SIZE;
        obuf += AES_BLOCK_SIZE;
    }
#endif
    return EXIT_SUCCESS;
}

AES_RETURN aes_ecb_decrypt(const unsigned char *ibuf, unsigned char *obuf,
                    int len, const aes_decrypt_ctx ctx[1])
{   int nb = len >> 4;

    if(len & (AES_BLOCK_SIZE - 1))
        return EXIT_FAILURE;

#if defined( USE_VIA_ACE_IF_PRESENT )

    if(ctx->inf.b[1] == 0xff)
    {   uint_8t *ksp = kd_adr(ctx);
        via_cwd(cwd, hybrid, dec, 2 * ctx->inf.b[0] - 192);

        if(ALIGN_OFFSET( ctx, 16 ))
            return EXIT_FAILURE;

        if(!ALIGN_OFFSET( ibuf, 16 ) && !ALIGN_OFFSET( obuf, 16 ))
        {
            via_ecb_op5(ksp,cwd,ibuf,obuf,nb);
        }
        else
        {   aligned_auto(uint_8t, buf, BFR_BLOCKS * AES_BLOCK_SIZE, 16);
            uint_8t *ip, *op;

            while(nb)
            {
                int m = (nb > BFR_BLOCKS ? BFR_BLOCKS : nb);

                ip = (ALIGN_OFFSET( ibuf, 16 ) ? buf : (uint_8t*)ibuf);
                op = (ALIGN_OFFSET( obuf, 16 ) ? buf : obuf);

                if(ip != ibuf)
                    memcpy(buf, ibuf, m * AES_BLOCK_SIZE);

                via_ecb_op5(ksp,cwd,ip,op,m);

                if(op != obuf)
                    memcpy(obuf, buf, m * AES_BLOCK_SIZE);

                ibuf += m * AES_BLOCK_SIZE;
                obuf += m * AES_BLOCK_SIZE;
                nb -= m;
            }
        }

        return EXIT_SUCCESS;
    }

#endif

#if !defined( ASSUME_VIA_ACE_PRESENT )
    while(nb--)
    {
        if(aes_decrypt(ibuf, obuf, ctx) != EXIT_SUCCESS)
			return EXIT_FAILURE;
        ibuf += AES_BLOCK_SIZE;
        obuf += AES_BLOCK_SIZE;
    }
#endif
    return EXIT_SUCCESS;
}

AES_RETURN aes_cbc_encrypt(const unsigned char *ibuf, unsigned char *obuf,
                    int len, unsigned char *iv, const aes_encrypt_ctx ctx[1])
{   int nb = len >> 4;

    if(len & (AES_BLOCK_SIZE - 1))
        return EXIT_FAILURE;

#if defined( USE_VIA_ACE_IF_PRESENT )

    if(ctx->inf.b[1] == 0xff)
    {   uint_8t *ksp = (uint_8t*)(ctx->ks), *ivp = iv;
        aligned_auto(uint_8t, liv, AES_BLOCK_SIZE, 16);
        via_cwd(cwd, hybrid, enc, 2 * ctx->inf.b[0] - 192);

        if(ALIGN_OFFSET( ctx, 16 ))
            return EXIT_FAILURE;

        if(ALIGN_OFFSET( iv, 16 ))   /* ensure an aligned iv */
        {
            ivp = liv;
            memcpy(liv, iv, AES_BLOCK_SIZE);
        }

        if(!ALIGN_OFFSET( ibuf, 16 ) && !ALIGN_OFFSET( obuf, 16 ) && !ALIGN_OFFSET( iv, 16 ))
        {
            via_cbc_op7(ksp,cwd,ibuf,obuf,nb,ivp,ivp);
        }
        else
        {   aligned_auto(uint_8t, buf, BFR_BLOCKS * AES_BLOCK_SIZE, 16);
            uint_8t *ip, *op;

            while(nb)
            {
                int m = (nb > BFR_BLOCKS ? BFR_BLOCKS : nb);

                ip = (ALIGN_OFFSET( ibuf, 16 ) ? buf : (uint_8t*)ibuf);
                op = (ALIGN_OFFSET( obuf, 16 ) ? buf : obuf);

                if(ip != ibuf)
                    memcpy(buf, ibuf, m * AES_BLOCK_SIZE);

                via_cbc_op7(ksp,cwd,ip,op,m,ivp,ivp);