myvtm/Other/libfilecryption/rvcfileheader.cpp

#include "stdafx.h"
#include "rvcfileheader.h"
#include "fileanalysis.h"
#include <string.h>


int constrcut_rvc_file_header(char* pbuffer, uint32_t* ulen, const char* pfilename, const filecryption_callback_t* pcallback, eRvcCryptionVersion eversion)
{
	int iret = -1;

	//1. 自定义文件头标识16位
	size_t udatalen = strlen(rvc_header);
	memcpy(pbuffer, rvc_header, udatalen);
	//2. 自定义文件头长度4位
	udatalen += sizeof(uint32_t);
	//3. 文件加密版本标识
	const char* strheader = cryption_ver_flag_table[0];
	if (eversion < sizeof(cryption_ver_flag_table)/sizeof(char*) && eversion >= 0){
		strheader = cryption_ver_flag_table[eversion];
	}
	if (0 == fill_tag_buffer(pbuffer + udatalen, *ulen - udatalen, strheader, strlen(strheader))){
		udatalen += (strlen(strheader) + sizeof(uint32_t));
	}

	//4. 源文件hash值
	char strhash[RVC_FILE_HASH_LEN] = {0};
	if (get_srcfile_hash(strhash, RVC_FILE_HASH_LEN, pfilename)){
		safe_log(pcallback, FILECRYPT_LEVEL_ERROR, "%s","get file hash failed!");
		return iret;
	}
	if (0 == fill_tag_buffer(pbuffer + udatalen, *ulen - udatalen, strhash, RVC_FILE_HASH_LEN)){
		udatalen += (RVC_FILE_HASH_LEN + sizeof(uint32_t));
	}

	//5. 源文件文件大小
	uint32_t usize = get_srcfile_size(pfilename);
	memcpy(pbuffer+udatalen, &usize, sizeof(uint32_t));
	udatalen += sizeof(uint32_t);

	//6. 源文件文件名
	char strname[MAX_PATH] = {0};
	get_srcfile_name(strname, MAX_PATH, pfilename);
	if (0 == fill_tag_buffer(pbuffer + udatalen, *ulen - udatalen, strname, strlen(strname))){
		udatalen += (strlen(strname) + sizeof(uint32_t));
	}

	//7. 真实文件格式，后缀名
	char strformat[MAX_PATH] = {0};
	get_srcfile_format(strformat, MAX_PATH, pfilename);
	if (0 == fill_tag_buffer(pbuffer + udatalen, *ulen - udatalen, strformat, strlen(strformat))){
		udatalen += (strlen(strformat) + sizeof(uint32_t));
	}

	*ulen = udatalen;
	memcpy(pbuffer+RVC_FILE_HEADER_FLAG_LEN, &udatalen, sizeof(uint32_t));
	iret = 0;
	return iret;
}


int get_rvc_file_header_info(rvc_fileheader_t* pdata, char* pheadbuffer, uint32_t ulen, const filecryption_callback_t* pcallback)
{
	int iret = -1;
	if (NULL == pheadbuffer){
		return iret;
	}
	//3. 文件加密版本标识
	size_t uindex = 0;
	if (0 == get_tag_value_from_buffer(pdata->strcryptver, RVC_CRYPTION_VER_FLAG_LEN, pheadbuffer+uindex, ulen - uindex)){
		uindex += (RVC_CRYPTION_VER_FLAG_LEN + sizeof(uint32_t));
	}
	else{
		return iret;
	}
	//4. 源文件hash值
	if (0 == get_tag_value_from_buffer((char*)pdata->strhash, RVC_FILE_HASH_LEN, pheadbuffer+uindex, ulen - uindex)){
		uindex += (RVC_FILE_HASH_LEN + sizeof(uint32_t));
	}
	else{
		return iret;
	}
	//5. 源文件文件大小
	memcpy(&pdata->usrcfilelen, pheadbuffer+uindex, sizeof(uint32_t));
	uindex += sizeof(uint32_t);
	//6. 源文件文件名
	if (0 == get_tag_value_from_buffer((char*)pdata->strsrcfilename, MAX_PATH, pheadbuffer+uindex, ulen - uindex)){
		uindex += (strlen(pdata->strsrcfilename) + sizeof(uint32_t));
	}
	else{
		return iret;
	}
	//7. 真实文件格式，后缀名
	if (0 == get_tag_value_from_buffer((char*)pdata->strsrcfileformat, MAX_PATH, pheadbuffer+uindex, ulen - uindex)){
		iret = 0;
	}

	return iret;
}


int fill_tag_buffer(char* pbuffer, uint32_t ubuffersize, const char* pdata, uint32_t udatalen)
{
	int iret = -1;
	if (NULL == pdata || NULL == pbuffer){
		return iret;
	}

	if (ubuffersize > udatalen + sizeof(uint32_t)){
		memcpy(pbuffer, &udatalen, sizeof(uint32_t));
		memcpy(pbuffer + sizeof(uint32_t), pdata, udatalen);
		iret = 0;
	}

	return iret;
}


int get_tag_value_from_buffer(char* pbuffer, uint32_t ubuffersize, const char* pdata, uint32_t udatalen)
{
	int iret = -1;
	if (NULL == pdata || NULL == pbuffer || udatalen < sizeof(uint32_t)){
		return iret;
	}

	int idatalen = 0;
	memcpy(&idatalen, pdata, sizeof(int));

	if (udatalen >= idatalen + sizeof(uint32_t) && ubuffersize >= idatalen){
		memcpy(pbuffer, pdata + sizeof(uint32_t), idatalen);
		iret = 0;
	}

	return iret;
}


int get_key_from_header_info(unsigned char* pkey, uint32_t ukeysize, char* pheader, uint32_t udatalen, const filecryption_callback_t* pcallback)
{
	int iret = -1;

	rvc_fileheader_t t_param = {0};
	if (0 != get_rvc_file_header_info(&t_param, pheader, udatalen, pcallback)){
		safe_log(pcallback, FILECRYPT_LEVEL_ERROR, "%s", "get rvc file header infos failed!");
		return iret;
	}

	if (0 == GenerateSM4Key(pkey, ukeysize, t_param.strhash, RVC_FILE_HASH_LEN, t_param.usrcfilelen)){
		safe_log(pcallback, FILECRYPT_LEVEL_DEBUG, "%s", "Generate SM4Key success!");
		iret = 0;
	}

	return iret;
}