/**********************************************************************
 *                          gost_crypt.c                              *
 *             Copyright (c) 2005-2006 Cryptocom LTD                  *
 *         This file is distributed under the same license as OpenSSL *
 *                                                                    *
 *       OpenSSL interface to GOST 28147-89 cipher functions          *
 *          Requires OpenSSL 0.9.9 for compilation                    *
 **********************************************************************/
#include <string.h>
#include "gost89.h"
#include <openssl/rand.h>
#include "e_gost_err.h"
#include "gost_lcl.h"

#if !defined(CCGOST_DEBUG) && !defined(DEBUG)
# ifndef NDEBUG
#  define NDEBUG
# endif
#endif
#include <assert.h>

static int gost_cipher_init(EVP_CIPHER_CTX *ctx, const unsigned char *key, 
	const unsigned char *iv, int enc);
static int	gost_cipher_init_cpa(EVP_CIPHER_CTX *ctx, const unsigned char *key,
	const unsigned char *iv, int enc);
/* Handles block of data in CFB mode */			
static int	gost_cipher_do_cfb(EVP_CIPHER_CTX *ctx, unsigned char *out,
	const unsigned char *in, size_t inl);
/* Handles block of data in CNT mode */			
static int	gost_cipher_do_cnt(EVP_CIPHER_CTX *ctx, unsigned char *out,
	const unsigned char *in, size_t inl);
/* Cleanup function */			
static int gost_cipher_cleanup(EVP_CIPHER_CTX *);
/* set/get cipher parameters */
static int gost89_set_asn1_parameters(EVP_CIPHER_CTX *ctx,ASN1_TYPE *params);
static int gost89_get_asn1_parameters(EVP_CIPHER_CTX *ctx,ASN1_TYPE *params);
/* Control function */
static int gost_cipher_ctl(EVP_CIPHER_CTX *ctx,int type,int arg,void *ptr);

EVP_CIPHER cipher_gost = 
	{
	NID_id_Gost28147_89,
	1,/*block_size*/
	32,/*key_size*/
	8,/*iv_len */
	EVP_CIPH_CFB_MODE| EVP_CIPH_NO_PADDING |
	EVP_CIPH_CUSTOM_IV| EVP_CIPH_RAND_KEY | EVP_CIPH_ALWAYS_CALL_INIT,
	gost_cipher_init,
	gost_cipher_do_cfb,
	gost_cipher_cleanup,
	sizeof(struct ossl_gost_cipher_ctx),/* ctx_size */
	gost89_set_asn1_parameters,
	gost89_get_asn1_parameters,
	gost_cipher_ctl,
	NULL,
	};

EVP_CIPHER cipher_gost_cpacnt = 
	{
	NID_gost89_cnt,
	1,/*block_size*/
	32,/*key_size*/
	8,/*iv_len */
	EVP_CIPH_OFB_MODE| EVP_CIPH_NO_PADDING |
	EVP_CIPH_CUSTOM_IV| EVP_CIPH_RAND_KEY | EVP_CIPH_ALWAYS_CALL_INIT,
	gost_cipher_init_cpa,
	gost_cipher_do_cnt,
	gost_cipher_cleanup,
	sizeof(struct ossl_gost_cipher_ctx), /* ctx_size */
	gost89_set_asn1_parameters,
	gost89_get_asn1_parameters,
	gost_cipher_ctl,
	NULL,
	};

/* Implementation of GOST 28147-89 in MAC (imitovstavka) mode */
/* Init functions which set specific parameters */
static int gost_imit_init_cpa(EVP_MD_CTX *ctx);
/* process block of data */
static int gost_imit_update(EVP_MD_CTX *ctx, const void *data, size_t count);
/* Return computed value */
static int gost_imit_final(EVP_MD_CTX *ctx,unsigned char *md);
/* Copies context */
static int gost_imit_copy(EVP_MD_CTX *to,const EVP_MD_CTX *from);
static int gost_imit_cleanup(EVP_MD_CTX *ctx);
/* Control function, knows how to set MAC key.*/
static int gost_imit_ctrl(EVP_MD_CTX *ctx,int type, int arg, void *ptr);

EVP_MD imit_gost_cpa =
	{
	NID_id_Gost28147_89_MAC,
	NID_undef,
	4,
	0,
	gost_imit_init_cpa,
	gost_imit_update,
	gost_imit_final,
	gost_imit_copy,
	gost_imit_cleanup,
	NULL,
	NULL,
	{0,0,0,0,0},
	8,
	sizeof(struct ossl_gost_imit_ctx), 
	gost_imit_ctrl
	};

/* 
 * Correspondence between gost parameter OIDs and substitution blocks
 * NID field is filed by register_gost_NID function in engine.c
 * upon engine initialization
 */

struct gost_cipher_info gost_cipher_list[]=
	{
/* NID */  /* Subst block */          /* Key meshing*/
/*{NID_id_GostR3411_94_CryptoProParamSet,&GostR3411_94_CryptoProParamSet,0},*/
	{NID_id_Gost28147_89_cc,&GostR3411_94_CryptoProParamSet,0},
	{NID_id_Gost28147_89_CryptoPro_A_ParamSet,&Gost28147_CryptoProParamSetA,1},
	{NID_id_Gost28147_89_CryptoPro_B_ParamSet,&Gost28147_CryptoProParamSetB,1},
	{NID_id_Gost28147_89_CryptoPro_C_ParamSet,&Gost28147_CryptoProParamSetC,1},
	{NID_id_Gost28147_89_CryptoPro_D_ParamSet,&Gost28147_CryptoProParamSetD,1},
	{NID_id_Gost28147_89_TestParamSet,&Gost28147_TestParamSet,1},
	{NID_undef,NULL,0}
	};	

/*  get encryption parameters from crypto network settings
	FIXME For now we use environment var CRYPT_PARAMS as place to 
	store these settings. Actually, it is better to use engine control   command, read from configuration file to set them */
const struct gost_cipher_info *get_encryption_params(ASN1_OBJECT *obj)
	{
	int nid;
	struct gost_cipher_info *param;
	if (!obj)
		{
		const char * params = get_gost_engine_param(GOST_PARAM_CRYPT_PARAMS);
		if (!params || !strlen(params)) 
			return &gost_cipher_list[1];

		nid = OBJ_txt2nid(params);
		if (nid == NID_undef)
			{
			GOSTerr(GOST_F_GET_ENCRYPTION_PARAMS,
				GOST_R_INVALID_CIPHER_PARAM_OID);
			return NULL;
			}	
		}
	else
		{
		nid= OBJ_obj2nid(obj);
		}
	for (param=gost_cipher_list;param->sblock!=NULL && param->nid!=nid; 
		 param++);
	if (!param->sblock)
		{
		GOSTerr(GOST_F_GET_ENCRYPTION_PARAMS,GOST_R_INVALID_CIPHER_PARAMS);
		return NULL;
		}	
	return param;
	}

/* Sets cipher param from paramset NID. */
static int gost_cipher_set_param(struct ossl_gost_cipher_ctx *c,int nid)
	{
	const struct gost_cipher_info *param;
	param=get_encryption_params((nid==NID_undef?NULL:OBJ_nid2obj(nid)));
	if (!param) return 0;
	
	c->paramNID = param->nid;
	c->key_meshing=param->key_meshing;
	c->count=0;
	gost_init(&(c->cctx), param->sblock);
	return 1;
	}

/* Initializes EVP_CIPHER_CTX by paramset NID */
static int gost_cipher_init_param(EVP_CIPHER_CTX *ctx, const unsigned char *key,
	const unsigned char *iv, int enc, int paramNID,int mode)
	{
	struct ossl_gost_cipher_ctx *c=ctx->cipher_data;
	if (ctx->app_data == NULL)
		{
		if (!gost_cipher_set_param(c,paramNID)) return 0;
		ctx->app_data = ctx->cipher_data;
		}
	if (key) gost_key(&(c->cctx),key);
	if(iv) memcpy(ctx->oiv, iv, EVP_CIPHER_CTX_iv_length(ctx));
	memcpy(ctx->iv, ctx->oiv, EVP_CIPHER_CTX_iv_length(ctx));
	return 1;
	}	

static int gost_cipher_init_cpa(EVP_CIPHER_CTX *ctx, const unsigned char *key,
	const unsigned char *iv, int enc)
	{
	struct ossl_gost_cipher_ctx *c=ctx->cipher_data;
	gost_init(&(c->cctx),&Gost28147_CryptoProParamSetA);
	c->key_meshing=1;
	c->count=0;
	if(key) gost_key(&(c->cctx),key);
	if(iv) memcpy(ctx->oiv, iv, EVP_CIPHER_CTX_iv_length(ctx));
	memcpy(ctx->iv, ctx->oiv, EVP_CIPHER_CTX_iv_length(ctx));
	return 1;
	}

/* Initializes EVP_CIPHER_CTX with default values */
int gost_cipher_init(EVP_CIPHER_CTX *ctx, const unsigned char *key,
	const unsigned char *iv, int enc)
	{
	return gost_cipher_init_param(ctx,key,iv,enc,NID_undef,EVP_CIPH_CFB_MODE);
	}	
/* Wrapper around gostcrypt function from gost89.c which perform
 * key meshing when nesseccary 
 */
static void gost_crypt_mesh (void *ctx,unsigned char *iv,unsigned char *buf)
	{
	struct ossl_gost_cipher_ctx *c = ctx;
	assert(c->count%8 == 0 && c->count <= 1024);
	if (c->key_meshing && c->count==1024)
		{
		cryptopro_key_meshing(&(c->cctx),iv);
		}	
	gostcrypt(&(c->cctx),iv,buf);
	c->count = c->count%1024 + 8;
	}

static void gost_cnt_next (void *ctx, unsigned char *iv, unsigned char *buf)
	{
	struct ossl_gost_cipher_ctx *c = ctx;
	word32 g,go;
	unsigned char buf1[8];
	assert(c->count%8 == 0 && c->count <= 1024);
	if (c->key_meshing && c->count==1024)
		{
		cryptopro_key_meshing(&(c->cctx),iv);
		}
	if (c->count==0)
		{
		gostcrypt(&(c->cctx),iv,buf1);
		}
	else
		{
		memcpy(buf1,iv,8);
		}	
	g = buf1[0]|(buf1[1]<<8)|(buf1[2]<<16)|(buf1[3]<<24);
	g += 0x01010101;
	buf1[0]=(unsigned char)(g&0xff);
	buf1[1]=(unsigned char)((g>>8)&0xff);
	buf1[2]=(unsigned char)((g>>16)&0xff);
	buf1[3]=(unsigned char)((g>>24)&0xff);
	g = buf1[4]|(buf1[5]<<8)|(buf1[6]<<16)|(buf1[7]<<24);
	go = g;
	g += 0x01010104;
	if (go > g)      /*  overflow*/
		g++;
	buf1[4]=(unsigned char)(g&0xff);
	buf1[5]=(unsigned char)((g>>8)&0xff);
	buf1[6]=(unsigned char)((g>>16)&0xff);
	buf1[7]=(unsigned char)((g>>24)&0xff);
	memcpy(iv,buf1,8);
	gostcrypt(&(c->cctx),buf1,buf);
	c->count = c->count%1024 + 8;
	}

/* GOST encryption in CFB mode */
int	gost_cipher_do_cfb(EVP_CIPHER_CTX *ctx, unsigned char *out,
	const unsigned char *in, size_t inl)
	{
	const unsigned char *in_ptr=in;
	unsigned char *out_ptr=out;
	size_t i=0;
	size_t j=0;
/* process partial block if any */
	if (ctx->num) 
		{
		for (j=ctx->num,i=0;j<8 && i<inl;j++,i++,in_ptr++,out_ptr++) 
			{
			if (!ctx->encrypt) ctx->buf[j+8]=*in_ptr;
			*out_ptr=ctx->buf[j]^(*in_ptr);
			if (ctx->encrypt) ctx->buf[j+8]=*out_ptr;
			}	
		if (j==8)
			{
			memcpy(ctx->iv,ctx->buf+8,8);
			ctx->num=0;
			}
		else
			{
			ctx->num=j;
			return 1;
			}	
		}	

	for (;i+8<inl;i+=8,in_ptr+=8,out_ptr+=8)
		{
		/*block cipher current iv */
		gost_crypt_mesh(ctx->cipher_data,ctx->iv,ctx->buf);
		/*xor next block of input text with it and output it*/
		/*output this block */
		if (!ctx->encrypt) memcpy(ctx->iv,in_ptr,8);
		for (j=0;j<8;j++)
			{
			out_ptr[j]=ctx->buf[j]^in_ptr[j];
			}	
		/* Encrypt */
		/* Next iv is next block of cipher text*/
		if (ctx->encrypt) memcpy(ctx->iv,out_ptr,8);
		}
/* Process rest of buffer */
	if (i<inl)
		{
		gost_crypt_mesh(ctx->cipher_data,ctx->iv,ctx->buf);
		if (!ctx->encrypt) memcpy(ctx->buf+8,in_ptr,inl-i);
		for (j=0;i<inl;j++,i++)
			{
			out_ptr[j]=ctx->buf[j]^in_ptr[j];
			}			
		ctx->num = j;
		if (ctx->encrypt) memcpy(ctx->buf+8,out_ptr,j);
		}
	else
		{
		ctx->num = 0;
		}	
	return 1;
	}

static int gost_cipher_do_cnt(EVP_CIPHER_CTX *ctx, unsigned char *out,
	const unsigned char *in, size_t inl)
	{
	const unsigned char *in_ptr=in;
	unsigned char *out_ptr=out;
	size_t i=0;
	size_t j;
/* process partial block if any */
	if (ctx->num) 
		{
		for (j=ctx->num,i=0;j<8 && i<inl;j++,i++,in_ptr++,out_ptr++) 
			{
			*out_ptr=ctx->buf[j]^(*in_ptr);
			}	
		if (j==8)
			{
			ctx->num=0;
			}
		else
			{
			ctx->num=j;
			return 1;
			}	
		}	

	for (;i+8<inl;i+=8,in_ptr+=8,out_ptr+=8)
		{
		/*block cipher current iv */
		/* Encrypt */
		gost_cnt_next(ctx->cipher_data,ctx->iv,ctx->buf);
		/*xor next block of input text with it and output it*/
		/*output this block */
		for (j=0;j<8;j++)
			{
			out_ptr[j]=ctx->buf[j]^in_ptr[j];
			}	
		}
/* Process rest of buffer */
	if (i<inl)
		{
		gost_cnt_next(ctx->cipher_data,ctx->iv,ctx->buf);
		for (j=0;i<inl;j++,i++)
			{
			out_ptr[j]=ctx->buf[j]^in_ptr[j];
			}			
		ctx->num = j;
		}
	else
		{
		ctx->num = 0;
		}	
	return 1;
	}

/* Cleaning up of EVP_CIPHER_CTX */
int gost_cipher_cleanup(EVP_CIPHER_CTX *ctx) 
	{
	gost_destroy(&((struct ossl_gost_cipher_ctx *)ctx->cipher_data)->cctx);
	ctx->app_data = NULL;
	return 1;
	}	

/* Control function for gost cipher */
int gost_cipher_ctl(EVP_CIPHER_CTX *ctx,int type,int arg,void *ptr)
	{
	switch (type)
		{
		case EVP_CTRL_RAND_KEY:
		{
		if (RAND_bytes((unsigned char *)ptr,ctx->key_len)<=0)
			{
			GOSTerr(GOST_F_GOST_CIPHER_CTL,GOST_R_RANDOM_GENERATOR_ERROR);
			return -1;
			}
		break;
		}
		case EVP_CTRL_PBE_PRF_NID:
			if (ptr) {
				*((int *)ptr)=  NID_id_HMACGostR3411_94;
				return 1;
			} else {
				return 0;
			}	
				
		default:
			GOSTerr(GOST_F_GOST_CIPHER_CTL,GOST_R_UNSUPPORTED_CIPHER_CTL_COMMAND);
			return -1;
		}
	return 1;
	}

/* Set cipher parameters from ASN1 structure */
int gost89_set_asn1_parameters(EVP_CIPHER_CTX *ctx,ASN1_TYPE *params)
	{
	int len=0;
	unsigned char *buf=NULL;
	unsigned char *p=NULL;
	struct ossl_gost_cipher_ctx *c = ctx->cipher_data;
	GOST_CIPHER_PARAMS *gcp = GOST_CIPHER_PARAMS_new();
	ASN1_OCTET_STRING *os = NULL;
	if (!gcp)
		{
		GOSTerr(GOST_F_GOST89_SET_ASN1_PARAMETERS, GOST_R_NO_MEMORY);
		return 0;
		}
	if (!ASN1_OCTET_STRING_set(gcp->iv, ctx->iv, ctx->cipher->iv_len))
		{
		GOST_CIPHER_PARAMS_free(gcp);
		GOSTerr(GOST_F_GOST89_SET_ASN1_PARAMETERS, GOST_R_NO_MEMORY);
		return 0;
		}
	ASN1_OBJECT_free(gcp->enc_param_set);
	gcp->enc_param_set = OBJ_nid2obj(c->paramNID);

	len = i2d_GOST_CIPHER_PARAMS(gcp, NULL);
	p = buf = (unsigned char*)OPENSSL_malloc(len);
	if (!buf)
		{
		GOST_CIPHER_PARAMS_free(gcp);
		GOSTerr(GOST_F_GOST89_SET_ASN1_PARAMETERS, GOST_R_NO_MEMORY);
		return 0;
		}
	i2d_GOST_CIPHER_PARAMS(gcp, &p);
	GOST_CIPHER_PARAMS_free(gcp);

	os = ASN1_OCTET_STRING_new();

	if(!os || !ASN1_OCTET_STRING_set(os, buf, len))
		{
		OPENSSL_free(buf);
		GOSTerr(GOST_F_GOST89_SET_ASN1_PARAMETERS, GOST_R_NO_MEMORY);
		return 0;
		}
	OPENSSL_free(buf);

	ASN1_TYPE_set(params, V_ASN1_SEQUENCE, os);
	return 1;
	}

/* Store parameters into ASN1 structure */
int  gost89_get_asn1_parameters(EVP_CIPHER_CTX *ctx,ASN1_TYPE *params)
	{
	int ret = -1;
	int len; 
	GOST_CIPHER_PARAMS *gcp = NULL;
	unsigned char *p;
	struct ossl_gost_cipher_ctx *c=ctx->cipher_data;
	if (ASN1_TYPE_get(params) != V_ASN1_SEQUENCE)
		{
		return ret;
		}

	p = params->value.sequence->data;

	gcp = d2i_GOST_CIPHER_PARAMS(NULL, (const unsigned char **)&p,
		params->value.sequence->length);

	len = gcp->iv->length;
	if (len != ctx->cipher->iv_len)
		{
		GOST_CIPHER_PARAMS_free(gcp);
		GOSTerr(GOST_F_GOST89_GET_ASN1_PARAMETERS,
			GOST_R_INVALID_IV_LENGTH);
		return -1;
		}
	if (!gost_cipher_set_param(c,OBJ_obj2nid(gcp->enc_param_set)))
		{
		GOST_CIPHER_PARAMS_free(gcp);
		return -1;
		}
	memcpy(ctx->oiv, gcp->iv->data, len);

	GOST_CIPHER_PARAMS_free(gcp);

	return 1;
	}


int gost_imit_init_cpa(EVP_MD_CTX *ctx)
	{
	struct ossl_gost_imit_ctx *c = ctx->md_data;
	memset(c->buffer,0,sizeof(c->buffer));
	memset(c->partial_block,0,sizeof(c->partial_block));
	c->count = 0;
	c->bytes_left=0;
	c->key_meshing=1;
	gost_init(&(c->cctx),&Gost28147_CryptoProParamSetA);
	return 1;
	}

static void mac_block_mesh(struct ossl_gost_imit_ctx *c,const unsigned char *data)
	{
	unsigned char buffer[8];
	/* We are using local buffer for iv because CryptoPro doesn't 
	 * interpret internal state of MAC algorithm as iv during keymeshing
	 * (but does initialize internal state from iv in key transport
	 */
	assert(c->count%8 == 0 && c->count <= 1024);
	if (c->key_meshing && c->count==1024)
		{
		cryptopro_key_meshing(&(c->cctx),buffer);
		}
	mac_block(&(c->cctx),c->buffer,data);
	c->count = c->count%1024 + 8;
	}

int gost_imit_update(EVP_MD_CTX *ctx, const void *data, size_t count)
	{
	struct ossl_gost_imit_ctx *c = ctx->md_data;
	const unsigned char *p = data;
	size_t bytes = count,i;
	if (!(c->key_set)) {
		GOSTerr(GOST_F_GOST_IMIT_UPDATE, GOST_R_MAC_KEY_NOT_SET);
		return 0;
	}
	if (c->bytes_left)
		{
		for (i=c->bytes_left;i<8&&bytes>0;bytes--,i++,p++)
			{
			c->partial_block[i]=*p;
			}
		if (i==8)
			{
			mac_block_mesh(c,c->partial_block);
			}
		else
			{
			c->bytes_left = i;
			return 1;
			}		
		}	
	while (bytes>8)
		{
		mac_block_mesh(c,p);
		p+=8;
		bytes-=8;
		}
	if (bytes>0)
		{
		memcpy(c->partial_block,p,bytes);
		}	
	c->bytes_left=bytes;
	return 1;
	}

int gost_imit_final(EVP_MD_CTX *ctx,unsigned char *md)
	{
	struct ossl_gost_imit_ctx *c = ctx->md_data;
	if (!c->key_set) {
		GOSTerr(GOST_F_GOST_IMIT_FINAL, GOST_R_MAC_KEY_NOT_SET);
		return 0;
	}
	if (c->count==0 && c->bytes_left)
		{
		unsigned char buffer[8];
		memset(buffer, 0, 8);
		gost_imit_update(ctx, buffer, 8);
		}
	if (c->bytes_left)
		{
		int i;
		for (i=c->bytes_left;i<8;i++)
			{
			c->partial_block[i]=0;
			}
		mac_block_mesh(c,c->partial_block);
		}
	get_mac(c->buffer,32,md);
	return 1;
	}

int gost_imit_ctrl(EVP_MD_CTX *ctx,int type, int arg, void *ptr)
	{
	switch (type)
		{
		case EVP_MD_CTRL_KEY_LEN:
			*((unsigned int*)(ptr)) = 32;
			return 1;
		case EVP_MD_CTRL_SET_KEY:
		{
		if (arg!=32) {
			GOSTerr(GOST_F_GOST_IMIT_CTRL, GOST_R_INVALID_MAC_KEY_LENGTH);
			return 0;
		}

		gost_key(&(((struct ossl_gost_imit_ctx*)(ctx->md_data))->cctx),ptr)	;
		((struct ossl_gost_imit_ctx*)(ctx->md_data))->key_set = 1;
		return 1;

		}
		default:
			return 0;
		}		
	}

int gost_imit_copy(EVP_MD_CTX *to,const EVP_MD_CTX *from)
	{
	memcpy(to->md_data,from->md_data,sizeof(struct ossl_gost_imit_ctx));
	return 1;
	}

/* Clean up imit ctx */
int gost_imit_cleanup(EVP_MD_CTX *ctx)
	{
	memset(ctx->md_data,0,sizeof(struct ossl_gost_imit_ctx));
	return 1;
	}