// CRC16 CCITT False function
uint16_t crc16_ccitt_false(const unsigned char *data, size_t length) {
uint16_t crc = 0xFFFF;
if (PRINTCRC){
printf("Initial CRC: 0x%04X\n", crc);
}
for (size_t i = 0; i < length; ++i) {
crc ^= data[i] << 8;
if (PRINTCRC){
printf("After XOR with byte %zu (0x%02X): 0x%04X\n", i, data[i], crc);
}
for (int j = 0; j < 8; ++j) {
if (crc & 0x8000) {
crc = (crc << 1) ^ 0x1021;
if (PRINTCRC){
printf("Bit %d set, after shift and XOR: 0x%04X\n", j, crc);
}
} else {
crc <<= 1;
if (PRINTCRC){
printf("Bit %d not set, after shift: 0x%04X\n", j, crc);
}
}
crc &= 0xFFFF; // Ensure crc stays within 16 bits
}
}
if (PRINTCRC){
printf("Final CRC: 0x%04X\n", crc);
}
return crc;
}
// Function to check the payload
bool check_payload(const unsigned char *pPayload, size_t payload_length) {
// 判断载荷是否在126~472之间
//printf("载荷长度: %zu\n", payload_length);
// printf("Payload (hex): ");
if (!(126 <= payload_length && payload_length <= 472)) {
printf("载荷长度不在126~472之间\n");
return false;
}
// 获取载荷偏移8~92之间的数据，并计算该数据的CRC16值
if (payload_length < 92) {
printf("载荷长度不足92字节\n");
return false;
}
uint16_t crcValue = crc16_ccitt_false(pPayload + 8, 84);
printf("crcValue: %d\n", crcValue);
// 获取载荷中记录CRC16值的偏移
size_t crcOffset = (crcValue % 200) + 92;
printf("crcOffset: %d\n", crcOffset);
if (crcOffset + 2 >= payload_length) {
printf("CRC16值偏移超出载荷长度\n");
return false;
}
// 获取载荷中记录的CRC16值
uint16_t data_crc = (pPayload[crcOffset] << 8) | pPayload[crcOffset + 1];
printf("data_crc: %d\n", data_crc);
// 对比计算的CRC16值与载荷中记录的CRC16值
if (data_crc != crcValue) {
printf("计算的CRC16值: 0x%04X, 记录的CRC16值: 0x%04X\n", crcValue, data_crc);
// return false;
}
// 判断偏移过后3个字节是否超过TCP载荷长度
if (crcOffset + 3 > payload_length) {
printf("偏移过后3个字节超出载荷长度\n");
return false;
}
// 提取一个用于校验的值，该值为127的整数倍
uint16_t value_after_crc = (pPayload[crcOffset + 2] << 8) | pPayload[crcOffset + 3];
// 判断校验值是否为127的整数倍
if (value_after_crc % 127 != 0) {
printf("校验值不是127的整数倍\n");
// return false;
}
// 获取加密的trigger数据偏移
size_t trigger_start = crcOffset + 12;
// 判断是否超过TCP载荷长度
if (trigger_start + 29 > payload_length) {
printf("触发器数据偏移超出载荷长度\n");
return false;
}
// 获取加密的trigger数据，该数据包含回连C2地址
unsigned char trigger_payload[29];
memcpy(trigger_payload, pPayload + trigger_start, 29);
// 获取加密trigger数据的key数据偏移
size_t xor_key_start = (crcValue % 55) + 8;
// 判断是否超过TCP载荷长度
if (xor_key_start + 29 > payload_length) {
printf("XOR密钥偏移超出载荷长度\n");
return false;
}
// 获取加密trigger数据的key
unsigned char xor_key[29];
memcpy(xor_key, pPayload + xor_key_start, 29);
// 使用key逐字节异或trigger，得到解密数据
unsigned char result[29];
for (size_t i = 0; i < 29; ++i) {
result[i] = trigger_payload[i] ^ xor_key[i];
}
// 输出解密数据的16进制数据
printf("Decrypted Payload (hex): ");
for (size_t i = 0; i < 29; ++i) {
printf("%02X", result[i]);
}
printf("\n");
// 解密解密数据，输出回连IP、端口、校验KEY的sha1值（本次测试流量校验KEY为字符串"testtest"）
if (sizeof( result ) / sizeof( result[0] ) < 29) {
printf("解密数据长度不足29字节\n");
return false;
}
return true;
}
int main() {
// 原始数据
unsigned char pPayload1[] = {
0x02, 0x9b, 0x01, 0x38, 0x70, 0x11, 0xfe, 0x69, 0x39, 0x07, 0x6f, 0x77, 0xc0, 0xbf, 0xda, 0x2c,
0x02, 0x67, 0xe7, 0xa5, 0xbc, 0x68, 0xc0, 0x0a, 0xc5, 0xd8, 0x2d, 0x3b, 0xfa, 0x5c, 0x13, 0xfc,
0xf7, 0x14, 0x34, 0x67, 0x26, 0x32, 0xd1, 0x5f, 0x3a, 0x40, 0xd6, 0xfa, 0x00, 0xb0, 0x26, 0x02,
0x18, 0x0d, 0xa7, 0xd4, 0x76, 0x67, 0xde, 0x3b, 0x3f, 0x0b, 0x76, 0x39, 0x68, 0x89, 0x36, 0x5f,
0x9e, 0x6a, 0xc7, 0xc4, 0x9d, 0x98, 0x23, 0xd7, 0xd8, 0xfa, 0xd1, 0xd8, 0xaa, 0xf7, 0xdc, 0xb2,
0x05, 0x82, 0x96, 0x7b, 0xea, 0x74, 0xb6, 0x29, 0x80, 0x2c, 0x63, 0xe8, 0xb5, 0x99, 0x47, 0x53,
0x03, 0x69, 0x7d, 0x6b, 0x28, 0x3b, 0x77, 0x7f, 0x35, 0x48, 0x57, 0xdf, 0x40, 0xf9, 0x2a, 0x46,
0xbb, 0x41, 0xbe, 0x61, 0x7d, 0xa9, 0xde, 0x84, 0xc5, 0xc4, 0xb6, 0x3b, 0xf2, 0x4d, 0x00, 0x68,
0x41, 0x86, 0x2a, 0xeb, 0xa0, 0x78, 0x05, 0x78, 0x8a, 0xa7, 0x12, 0x68, 0x1a, 0xb4, 0xad, 0xcf,
0xec, 0x6d, 0x6e, 0x99, 0xe3, 0x37, 0xc6, 0x85, 0x62, 0xdb, 0xdd, 0x27, 0x38, 0x88, 0xef, 0xa3,
0x4a, 0x57, 0xb4, 0x48, 0x37, 0x45, 0x7a, 0x60, 0x2d, 0x8c, 0xc8, 0x47, 0x40, 0x76, 0x17, 0x2d,
0xe3, 0x85, 0xc6, 0xc7, 0xbc, 0x8d, 0x4c, 0x1f, 0x68, 0x29, 0x46, 0xa0, 0xb1, 0x35, 0x43, 0xfc,
0x8c, 0xf8, 0x44, 0xc4, 0x3d, 0xbe, 0x24, 0x6a, 0x4b, 0xec, 0xcb, 0x18, 0xb6, 0x2c, 0x8b, 0x84,
0x64, 0xe7, 0xf0, 0xd0, 0xa0, 0xc5, 0x92, 0x97, 0x48, 0x36, 0xf1, 0x53, 0x4a, 0x45, 0x83, 0x30,
0x31, 0x50, 0x74, 0xf5, 0x8d, 0x33, 0x19, 0xf7, 0x7e, 0x05, 0xa9, 0x09, 0x68, 0x71, 0xc2, 0xae,
0xbf, 0x41, 0xbb, 0xca, 0x4d, 0x14, 0xf3, 0xc1, 0x97, 0x63, 0xd6, 0xcc, 0x07, 0x2f, 0xfc, 0x38,
0x7f, 0x71, 0x2d, 0x0d, 0xa4, 0x46, 0x04, 0x22, 0x4c, 0xad, 0x2b, 0xb4, 0x1f, 0xed, 0x62, 0xde,
0x2e, 0x1d, 0xa8, 0x7b, 0x31, 0x9c, 0x3d, 0xc9, 0xff, 0x13, 0x95, 0x06, 0x42, 0x91, 0x3f, 0xc2
};
unsigned char pPayload[] = {
0x02, 0x9b, 0x01, 0x38, 0x70, 0x11, 0xfe, 0x69, 0x39, 0x07, 0x6f, 0x77, 0xc0, 0xbf, 0xda, 0x2c,
0x02, 0x67, 0xe7, 0xa5, 0xbc, 0x68, 0xc0, 0x0a, 0xc5, 0xd8, 0x2d, 0x3b, 0xfa, 0x5c, 0x13, 0xfc,
0xf7, 0x14, 0x34, 0x67, 0x26, 0x32, 0xd1, 0x5f, 0x3a, 0x40, 0xd6, 0xfa, 0x00, 0xb0, 0x26, 0x02,
0x18, 0x0d, 0xa7, 0xd4, 0x76, 0x67, 0xde, 0x3b, 0x3f, 0x0b, 0x76, 0x39, 0x68, 0x89, 0x36, 0x5f,
0x9e, 0x6a, 0xc7, 0xc4, 0x9d, 0x98, 0x23, 0xd7, 0xd8, 0xfa, 0xd1, 0xd8, 0xaa, 0xf7, 0xdb, 0xc2,
0x05, 0x82, 0x96, 0x7b, 0xea, 0x74, 0xb6, 0x29, 0x80, 0x2c, 0x63, 0xe8, 0xb5, 0x99, 0x47, 0x53,
0x03, 0x69, 0x7d, 0x6b, 0x28, 0x3b, 0x77, 0x7f, 0x35, 0x48, 0x57, 0xdf, 0x40, 0xf9, 0x2a, 0x46,
0xbb, 0x41, 0xbe, 0x61, 0x7d, 0xa9, 0xde, 0x84, 0xc5, 0xc4, 0xb6, 0x3b, 0xf2, 0x4d, 0x00, 0x68,
0x41, 0x86, 0x2a, 0xeb, 0xa0, 0x78, 0x05, 0x78, 0x8a, 0xa7, 0x12, 0x68, 0x1a, 0xb4, 0xad, 0xcf,
0xec, 0x6d, 0x6e, 0x99, 0xe3, 0x37, 0xc6, 0x85, 0x62, 0xdb, 0xdd, 0x27, 0x38, 0x88, 0xef, 0xa3,
0x4a, 0x57, 0xb4, 0x48, 0x37, 0x45, 0x7a, 0x60, 0x2d, 0x8c, 0xc8, 0x47, 0x40, 0x76, 0x17, 0x2d,
0xe3, 0x85, 0xc6, 0xc7, 0xbc, 0x8d, 0x4c, 0x1f, 0x68, 0x29, 0x46, 0xa0, 0xb1, 0x35, 0x43, 0xfc,
0x8c, 0xf8, 0x44, 0xc4, 0x3d, 0xbe, 0x24, 0x6a, 0x4b, 0xec, 0xb1, 0x8b, 0x62, 0xc8, 0xb8, 0x46,
0x4e, 0x7f, 0x0d, 0x0a, 0x0c, 0x59, 0x29, 0x74, 0x83, 0x6f, 0x15, 0x34, 0xa4
};
size_t payload_length = sizeof(pPayload);
bool result = check_payload(pPayload, payload_length);
if (result) {
printf("所有条件满足，返回1\n");
} else {
printf("条件不满足，返回0\n");
}
return 0;
}