/* Copyright (c) (2011,2012,2015,2016,2017,2019) Apple Inc. All rights reserved.
 *
 * corecrypto is licensed under Apple Inc.’s Internal Use License Agreement (which
 * is contained in the License.txt file distributed with corecrypto) and only to 
 * people who accept that license. IMPORTANT:  Any license rights granted to you by 
 * Apple Inc. (if any) are limited to internal use within your organization only on 
 * devices and computers you own or control, for the sole purpose of verifying the 
 * security characteristics and correct functioning of the Apple Software.  You may 
 * not, directly or indirectly, redistribute the Apple Software or any portions thereof.
 */

/*
 ---------------------------------------------------------------------------
 Copyright (c) 2003, Dr 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 28/01/2004

 This file contains the code for implementing encryption and decryption
 for AES (Rijndael) for block and key sizes of 16, 24 and 32 bytes. It
 can optionally be replaced by code written in assembler using NASM. For
 further details see the file aesopt.h
*/

#include "ccaes_gladman_opt.h"
#include "ccaes_gladman_tab.h"
#include <string.h>

#define ki(y,x,k,c) (s(y,c) = s(x, c) ^ (k)[c])
#define xo(y,x,c) (s(y,c) ^= s(x, c))
#define si(y,x,c)   (s(y,c) = word_in(x, c))
#define so(y,x,c)   word_out(y, c, s(x,c))

#if defined(ARRAYS)
#define locals(y,x)     x[4],y[4]
#else
#define locals(y,x)     x##0,x##1,x##2,x##3,y##0,y##1,y##2,y##3
#endif

#define dtables(tab)     const aes_32t *tab##0, *tab##1, *tab##2, *tab##3
#define itables(tab)     tab##0 = tab[0]; tab##1 = tab[1]; tab##2 = tab[2]; tab##3 = tab[3]

#define l_copy(y, x)    s(y,0) = s(x,0); s(y,1) = s(x,1); \
                        s(y,2) = s(x,2); s(y,3) = s(x,3);

#define key_in(y,x,k)   ki(y,x,k,0); ki(y,x,k,1); ki(y,x,k,2); ki(y,x,k,3)
#define cbc(y,x)        xo(y,x,0); xo(y,x,1); xo(y,x,2); xo(y,x,3)
#define state_in(y,x)   si(y,x,0); si(y,x,1); si(y,x,2); si(y,x,3)
#define state_out(y,x)  so(y,x,0); so(y,x,1); so(y,x,2); so(y,x,3)
#define round(rm,y,x,k) rm(y,x,k,0); rm(y,x,k,1); rm(y,x,k,2); rm(y,x,k,3)

#if defined(ENCRYPTION) && !defined(AES_ASM)

/* Visual C++ .Net v7.1 provides the fastest encryption code when using
   Pentium optimiation with small code but this is poor for decryption
   so we need to control this with the following VC++ pragmas
*/

#if defined(_MSC_VER) && !defined(__clang__)
#pragma optimize( "s", on )
#endif

/* Given the column (c) of the output state variable, the following
   macros give the input state variables which are needed in its
   computation for each row (r) of the state. All the alternative
   macros give the same end values but expand into different ways
   of calculating these values.  In particular the complex macro
   used for dynamically variable block sizes is designed to expand
   to a compile time constant whenever possible but will expand to
   conditional clauses on some branches (I am grateful to Frank
   Yellin for this construction)
*/

#define fwd_var(x,r,c)\
 ( r == 0 ? ( c == 0 ? s(x,0) : c == 1 ? s(x,1) : c == 2 ? s(x,2) : s(x,3))\
 : r == 1 ? ( c == 0 ? s(x,1) : c == 1 ? s(x,2) : c == 2 ? s(x,3) : s(x,0))\
 : r == 2 ? ( c == 0 ? s(x,2) : c == 1 ? s(x,3) : c == 2 ? s(x,0) : s(x,1))\
 :          ( c == 0 ? s(x,3) : c == 1 ? s(x,0) : c == 2 ? s(x,1) : s(x,2)))

#if defined(FT4_SET)
#undef  dec_fmvars
#  if defined(ENC_ROUND_CACHE_TABLES)
#define fwd_rnd(y,x,k,c)    (s(y,c) = (k)[c] ^ four_cached_tables(x,t_fn,fwd_var,rf1,c))
#  else
#define fwd_rnd(y,x,k,c)    (s(y,c) = (k)[c] ^ four_tables(x,t_fn,fwd_var,rf1,c))
#  endif
#elif defined(FT1_SET)
#undef  dec_fmvars
#define fwd_rnd(y,x,k,c)    (s(y,c) = (k)[c] ^ one_table(x,upr,t_fn,fwd_var,rf1,c))
#else
#define fwd_rnd(y,x,k,c)    (s(y,c) = (k)[c] ^ fwd_mcol(no_table(x,t_sbox,fwd_var,rf1,c)))
#endif

#if defined(FL4_SET)
#  if defined(LAST_ENC_ROUND_CACHE_TABLES)
#define fwd_lrnd(y,x,k,c)   (s(y,c) = (k)[c] ^ four_cached_tables(x,t_fl,fwd_var,rf1,c))
#  else
#define fwd_lrnd(y,x,k,c)   (s(y,c) = (k)[c] ^ four_tables(x,t_fl,fwd_var,rf1,c))
#  endif
#elif defined(FL1_SET)
#define fwd_lrnd(y,x,k,c)   (s(y,c) = (k)[c] ^ one_table(x,ups,t_fl,fwd_var,rf1,c))
#else
#define fwd_lrnd(y,x,k,c)   (s(y,c) = (k)[c] ^ no_table(x,t_sbox,fwd_var,rf1,c))
#endif

int ccaes_gladman_encrypt(const cccbc_ctx *key, cccbc_iv *iv, size_t num_blk,
                          const void *in, void *out)
{
    aes_32t         locals(b0, b1);
    const ccaes_gladman_encrypt_ctx *cx = (const ccaes_gladman_encrypt_ctx *)key;
    const aes_32t   *kp;
    const aes_32t   *kptr = cx->ks;
	int				cbcEnable = (cx->cbcEnable) ? 1 : 0;

#if defined(ENC_ROUND_CACHE_TABLES)
	dtables(t_fn);
#endif
#if defined(LAST_ENC_ROUND_CACHE_TABLES)
	dtables(t_fl);
#endif

#if defined( dec_fmvars )
    dec_fmvars; /* declare variables for fwd_mcol() if needed */
#endif

	// Load IV into b0.
	state_in(b0, iv);

	for (;num_blk; in += AES_BLOCK_SIZE, out += AES_BLOCK_SIZE, --num_blk)
	{
		kp = kptr;
#if 0
		// Read the plaintext into b1
		state_in(b1, in);
		if(cbcEnable) {
			// Do the CBC with b0 which is either the iv or the ciphertext of the
			// previous block.
			cbc(b1, b0);
		}

		// Xor b1 with the key schedule to get things started.
		key_in(b0, b1, kp);
#else
		if(cbcEnable) {
			// Since xor is associative we mess with the ordering here to get
			// the loads started early
			key_in(b1, b0, kp);  // Xor b0(IV) with the key schedule and assign to b1
			state_in(b0, in);    // Load block into b0
			cbc(b0, b1);         // Xor b0 with b1 and store in b0
		}
		else {
			// Read the plaintext into b1
			state_in(b1, in);
			key_in(b0, b1, kp);
		}
#endif	/* 0 */

#if defined(ENC_ROUND_CACHE_TABLES)
		itables(t_fn);
#endif

#if (ENC_UNROLL == FULL)

		switch(cx->rn)
		{
		case 14:
			round(fwd_rnd,  b1, b0, kp + 1 * N_COLS);
			round(fwd_rnd,  b0, b1, kp + 2 * N_COLS);
			kp += 2 * N_COLS;
		case 12:
			round(fwd_rnd,  b1, b0, kp + 1 * N_COLS);
			round(fwd_rnd,  b0, b1, kp + 2 * N_COLS);
			kp += 2 * N_COLS;
		case 10:
		default:
			round(fwd_rnd,  b1, b0, kp + 1 * N_COLS);
			round(fwd_rnd,  b0, b1, kp + 2 * N_COLS);
			round(fwd_rnd,  b1, b0, kp + 3 * N_COLS);
			round(fwd_rnd,  b0, b1, kp + 4 * N_COLS);
			round(fwd_rnd,  b1, b0, kp + 5 * N_COLS);
			round(fwd_rnd,  b0, b1, kp + 6 * N_COLS);
			round(fwd_rnd,  b1, b0, kp + 7 * N_COLS);
			round(fwd_rnd,  b0, b1, kp + 8 * N_COLS);
			round(fwd_rnd,  b1, b0, kp + 9 * N_COLS);
#if defined(LAST_ENC_ROUND_CACHE_TABLES)
			itables(t_fl);
#endif
			round(fwd_lrnd, b0, b1, kp +10 * N_COLS);
		}

#else

		{   aes_32t    rnd;
#if (ENC_UNROLL == PARTIAL)
			for(rnd = 0; rnd < (cx->rn >> 1) - 1; ++rnd)
			{
				kp += N_COLS;
				round(fwd_rnd, b1, b0, kp);
				kp += N_COLS;
				round(fwd_rnd, b0, b1, kp);
			}
			kp += N_COLS;
			round(fwd_rnd,  b1, b0, kp);
#else
			for(rnd = 0; rnd < cx->rn - 1; ++rnd)
			{
				kp += N_COLS;
				round(fwd_rnd, b1, b0, kp);
				l_copy(b0, b1);
			}
#endif
#if defined(LAST_ENC_ROUND_CACHE_TABLES)
			itables(t_fl);
#endif
			kp += N_COLS;
			round(fwd_lrnd, b0, b1, kp);
		}
#endif

		state_out(out, b0);
	}

	if(cbcEnable) {
		state_out(iv, b0);
	}
    
    return 0;
}

#endif

#if defined(DECRYPTION) && !defined(AES_ASM)

/* Visual C++ .Net v7.1 provides the fastest encryption code when using
   Pentium optimiation with small code but this is poor for decryption
   so we need to control this with the following VC++ pragmas
*/

#if defined(_MSC_VER) && !defined(__clang__ )
#pragma optimize( "t", on )
#endif

/* Given the column (c) of the output state variable, the following
   macros give the input state variables which are needed in its
   computation for each row (r) of the state. All the alternative
   macros give the same end values but expand into different ways
   of calculating these values.  In particular the complex macro
   used for dynamically variable block sizes is designed to expand
   to a compile time constant whenever possible but will expand to
   conditional clauses on some branches (I am grateful to Frank
   Yellin for this construction)
*/

#define inv_var(x,r,c)\
 ( r == 0 ? ( c == 0 ? s(x,0) : c == 1 ? s(x,1) : c == 2 ? s(x,2) : s(x,3))\
 : r == 1 ? ( c == 0 ? s(x,3) : c == 1 ? s(x,0) : c == 2 ? s(x,1) : s(x,2))\
 : r == 2 ? ( c == 0 ? s(x,2) : c == 1 ? s(x,3) : c == 2 ? s(x,0) : s(x,1))\
 :          ( c == 0 ? s(x,1) : c == 1 ? s(x,2) : c == 2 ? s(x,3) : s(x,0)))

#if defined(IT4_SET)
#undef  dec_imvars
#  if defined(DEC_ROUND_CACHE_TABLES)
#define inv_rnd(y,x,k,c)    (s(y,c) = (k)[c] ^ four_cached_tables(x,t_in,inv_var,rf1,c))
#  else
#define inv_rnd(y,x,k,c)    (s(y,c) = (k)[c] ^ four_tables(x,t_in,inv_var,rf1,c))
#  endif
#elif defined(IT1_SET)
#undef  dec_imvars
#define inv_rnd(y,x,k,c)    (s(y,c) = (k)[c] ^ one_table(x,upr,t_in,inv_var,rf1,c))
#else
#define inv_rnd(y,x,k,c)    (s(y,c) = inv_mcol((k)[c] ^ no_table(x,t_ibox,inv_var,rf1,c)))
#endif

#if defined(IL4_SET)
#  if defined(LAST_DEC_ROUND_CACHE_TABLES)
#define inv_lrnd(y,x,k,c)   (s(y,c) = (k)[c] ^ four_cached_tables(x,t_il,inv_var,rf1,c))
#  else
#define inv_lrnd(y,x,k,c)   (s(y,c) = (k)[c] ^ four_tables(x,t_il,inv_var,rf1,c))
#  endif
#elif defined(IL1_SET)
#define inv_lrnd(y,x,k,c)   (s(y,c) = (k)[c] ^ one_table(x,ups,t_il,inv_var,rf1,c))
#else
#define inv_lrnd(y,x,k,c)   (s(y,c) = (k)[c] ^ no_table(x,t_ibox,inv_var,rf1,c))
#endif

int ccaes_gladman_decrypt(const cccbc_ctx *key, cccbc_iv *iv, size_t num_blk,
                          const void *in, void *out)
{
    aes_32t        locals(b0, b1);
    const ccaes_gladman_decrypt_ctx *cx = (const ccaes_gladman_decrypt_ctx *)key;
    const aes_32t *kptr = cx->ks + cx->rn * N_COLS;
	const aes_32t *kp;
#if defined(DEC_ROUND_CACHE_TABLES)
	dtables(t_in);
#endif
#if defined(LAST_DEC_ROUND_CACHE_TABLES)
	dtables(t_il);
#endif
	int cbcEnable = (cx->cbcEnable) ? 1 : 0;
	unsigned char lastIv[AES_BLOCK_SIZE];

	/* fix a compiler warning... */
	//b00 = 0; b01 = 0; b02=0; b03 = 0;

#if defined( dec_imvars )
    dec_imvars; /* declare variables for inv_mcol() if needed */
#endif

	if(cbcEnable & (num_blk == 0)) {
        return 0;
    }
    
#if defined(DEC_ROUND_CACHE_TABLES)
	itables(t_in);
#endif

	in += AES_BLOCK_SIZE * (num_blk - 1);
	out += AES_BLOCK_SIZE * (num_blk - 1);
	// Load the last block's ciphertext into b1
	state_in(b1, in);

	/* save that last ciphertext block for next op's chain */
	if(cbcEnable & (num_blk != 0)) {
		memmove(lastIv, in, AES_BLOCK_SIZE);
	}

	for (;num_blk; out -= AES_BLOCK_SIZE, --num_blk)
	{
		kp = kptr;
		// Do the xor part of state_in, where b1 is the previous block's ciphertext.
		key_in(b0, b1, kp);

#if (DEC_UNROLL == FULL)

		switch(cx->rn)
		{
		case 14:
			round(inv_rnd,  b1, b0, kp -  1 * N_COLS);
			round(inv_rnd,  b0, b1, kp -  2 * N_COLS);
			kp -= 2 * N_COLS;
		case 12:
			round(inv_rnd,  b1, b0, kp -  1 * N_COLS);
			round(inv_rnd,  b0, b1, kp -  2 * N_COLS);
			kp -= 2 * N_COLS;
		case 10:
		default:
			round(inv_rnd,  b1, b0, kp -  1 * N_COLS);
			round(inv_rnd,  b0, b1, kp -  2 * N_COLS);
			round(inv_rnd,  b1, b0, kp -  3 * N_COLS);
			round(inv_rnd,  b0, b1, kp -  4 * N_COLS);
			round(inv_rnd,  b1, b0, kp -  5 * N_COLS);
			round(inv_rnd,  b0, b1, kp -  6 * N_COLS);
			round(inv_rnd,  b1, b0, kp -  7 * N_COLS);
			round(inv_rnd,  b0, b1, kp -  8 * N_COLS);
			round(inv_rnd,  b1, b0, kp -  9 * N_COLS);
#if defined(LAST_DEC_ROUND_CACHE_TABLES)
			itables(t_il);
#endif
			round(inv_lrnd, b0, b1, kp - 10 * N_COLS);
		}

#else

		{   aes_32t    rnd;
#if (DEC_UNROLL == PARTIAL)
			for(rnd = 0; rnd < (cx->rn >> 1) - 1; ++rnd)
			{
				kp -= N_COLS;
				round(inv_rnd, b1, b0, kp);
				kp -= N_COLS;
				round(inv_rnd, b0, b1, kp);
			}
			kp -= N_COLS;
			round(inv_rnd, b1, b0, kp);
#else
			for(rnd = 0; rnd < cx->rn - 1; ++rnd)
			{
				kp -= N_COLS;
				round(inv_rnd, b1, b0, kp);
				l_copy(b0, b1);
			}
#endif
#if defined(LAST_DEC_ROUND_CACHE_TABLES)
			itables(t_il);
#endif
			kp -= N_COLS;
			round(inv_lrnd, b0, b1, kp);
		}
#endif

		if(cbcEnable) {
			if (num_blk == 1)
			{
				// We are doing the first block so we need the IV rather than the previous
				// block for CBC (there is no previous block)
				state_in(b1, iv);
			}
			else
			{
				in -= AES_BLOCK_SIZE;
				state_in(b1, in);
			}

			// Do the CBC with b1 which is either the IV or the ciphertext of
			// the previous block.
			cbc(b0, b1);
		}
		else {
			if (num_blk != 1) {
				/* skip this the last time through */
				in -= AES_BLOCK_SIZE;
				state_in(b1, in);
			}
		}
		state_out(out, b0);
	}

	/* save last ciphertext block for next op's chain */
	if(cbcEnable) {
		memmove(iv, lastIv, AES_BLOCK_SIZE);
	}
    
    return 0;
}

#endif
