module-gbox-helper.c

#define MODULE_LOG_PREFIX "gbox"

#include "globals.h"

#ifdef MODULE_GBOX
#include "minilzo/minilzo.h"
#include "ncam-string.h"


uint16_t gbox_get_caid(uint32_t caprovid)
{
	if ((caprovid >> 24) == 0x05)
		{ return 0x0500; }
	else
		{ return caprovid >> 16; }
}

uint32_t gbox_get_provid(uint32_t caprovid)
{
	uint32_t provid = 0;

	switch(caprovid >> 24)
	{
		case 0x05: // ViXS
			provid = caprovid & 0xFFFFFF;
			break;

		case 0x0D: // Cryptoworx
			provid = (caprovid >> 8) & 0xFF;
			break;

		default:
			provid = caprovid & 0xFFFF;
			break;
	}
	return provid;
}

uint32_t gbox_get_caprovid(uint16_t caid, uint32_t prid)
{
	uint32_t caprovid = 0;

	switch(caid >> 8)
	{
		case 0x05: // ViXS
			caprovid = (caid >> 8) << 24 | (prid & 0xFFFFFF);
			break;

		case 0x0D: // Cryptoworks
			caprovid = (caid >> 8) << 24 | (caid & 0xFF) << 16 | ((prid << 8) & 0xFF00);
			break;

		case 0x18: // Nagra
			caprovid = (caid >> 8) << 24 | (caid & 0xFF) << 16;
			break;

		default:
			caprovid = (caid >> 8) << 24 | (caid & 0xFF) << 16 | (prid & 0xFFFF);
			break;
	}
	return caprovid;
}

static void gbox_convert_pw(uint8_t *password, uint32_t pw)
{
	int32_t i;
	for(i = 3; i >= 0; i--)
	{
		password[3 - i] = (pw >> (8 * i)) & 0xff;
	}
}

uint32_t gbox_get_checksum(uint8_t *buf, uint16_t buflen)
{
	uint8_t checksum[4];
	int32_t counter;

	checksum[3] = buf[0];
	checksum[2] = buf[1];
	checksum[1] = buf[2];
	checksum[0] = buf[3];

	for(counter = 1; counter < (buflen / 4) - 4; counter++)
	{
		checksum[3] ^= buf[counter * 4];
		checksum[2] ^= buf[counter * 4 + 1];
		checksum[1] ^= buf[counter * 4 + 2];
		checksum[0] ^= buf[counter * 4 + 3];
	}

	return checksum[3] << 24 | checksum[2] << 16 | checksum[1] << 8 | checksum[0];
}

////////////////////////////////////////////////////////////////////////////////
// GBOX BUFFER ENCRYPTION/DECRYPTION (thanks to dvbcrypt@gmail.com)
////////////////////////////////////////////////////////////////////////////////

static uint8_t Lookup_Table[0x40] =
{
	0x25, 0x38, 0xD4, 0xCD, 0x17, 0x7A, 0x5E, 0x6C, 0x52, 0x42, 0xFE, 0x68, 0xAB, 0x3F, 0xF7, 0xBE,
	0x47, 0x57, 0x71, 0xB0, 0x23, 0xC1, 0x26, 0x6C, 0x41, 0xCE, 0x94, 0x37, 0x45, 0x04, 0xA2, 0xEA,
	0x07, 0x58, 0x35, 0x55, 0x08, 0x2A, 0x0F, 0xE7, 0xAC, 0x76, 0xF0, 0xC1, 0xE6, 0x09, 0x10, 0xDD,
	0xC5, 0x8D, 0x2E, 0xD9, 0x03, 0x9C, 0x3D, 0x2C, 0x4D, 0x41, 0x0C, 0x5E, 0xDE, 0xE4, 0x90, 0xAE
};

static void gbox_encrypt8(uint8_t *buffer, uint8_t *pass)
{
	int passcounter;
	int bufcounter;
	uint8_t temp;

	for(passcounter = 0; passcounter < 4; passcounter++)
	{
		for(bufcounter = 7; bufcounter >= 0; bufcounter--)
		{
			temp = pass[3];
			pass[3] = (pass[3] / 2) + (pass[2] & 1) * 0x80;
			pass[2] = (pass[2] / 2) + (pass[1] & 1) * 0x80;
			pass[1] = (pass[1] / 2) + (pass[0] & 1) * 0x80;
			pass[0] = (pass[0] / 2) + (temp   & 1) * 0x80;
			buffer[(bufcounter + 1) & 7] = buffer[(bufcounter + 1) & 7 ] - Lookup_Table[(buffer[bufcounter] >> 2) & 0x3F ];
			buffer[(bufcounter + 1) & 7] = Lookup_Table[(buffer[bufcounter] - pass[(bufcounter + 1) & 3]) & 0x3F ] ^ buffer[(bufcounter + 1) & 7 ];
			buffer[(bufcounter + 1) & 7] = buffer[(bufcounter + 1) & 7 ] - pass[(bufcounter & 3)];
		}
	}
}

static void gbox_decrypt8(uint8_t *buffer, uint8_t *pass)
{
	uint8_t temp;
	int bufcounter;
	int passcounter;

	for(passcounter = 3; passcounter >= 0; passcounter--)
	{
		for(bufcounter = 0; bufcounter <= 7; bufcounter++)
		{
			buffer[(bufcounter + 1) & 7] = pass[bufcounter & 3] + buffer[(bufcounter + 1) & 7];
			temp = buffer[bufcounter] - pass[(bufcounter + 1) & 3];
			buffer[(bufcounter + 1) & 7] = Lookup_Table[temp & 0x3F] ^ buffer[(bufcounter + 1) & 7];
			temp = buffer[bufcounter] >> 2;
			buffer[(bufcounter + 1) & 7] =  Lookup_Table[temp & 0x3F] + buffer[(bufcounter + 1) & 7];
			temp = pass[0] & 0x80;
			pass[0] = ((pass[1] & 0x80) >> 7) + (pass[0] << 1);
			pass[1] = ((pass[2] & 0x80) >> 7) + (pass[1] << 1);
			pass[2] = ((pass[3] & 0x80) >> 7) + (pass[2] << 1);
			pass[3] = (temp >> 7) + (pass[3] << 1);
		}
	}
}

static void gbox_decryptB(uint8_t *buffer, int bufsize, uint8_t *localkey)
{
	int counter;
	gbox_encrypt8(&buffer[bufsize - 9], localkey);
	gbox_decrypt8(buffer, localkey);
	for(counter = bufsize - 2; counter >= 0; counter--)
		{ buffer[counter] = buffer[counter + 1] ^ buffer[counter]; }
}

static void gbox_encryptB(uint8_t *buffer, int bufsize, uint8_t *key)
{
	int counter;
	for(counter = 0; counter < (bufsize - 1); counter++)
		{ buffer[counter] = buffer[counter + 1] ^ buffer[counter]; }
	gbox_encrypt8(buffer, key);
	gbox_decrypt8(&buffer[bufsize - 9], key);
}

static void gbox_encryptA(uint8_t *buffer, uint8_t *pass)
{
	int counter;
	uint8_t temp;

	for(counter = 0x1F; counter >= 0; counter--)
	{
		temp = pass[3] & 1;
		pass[3] = ((pass[2] & 1) << 7) + (pass[3] >> 1);
		pass[2] = ((pass[1] & 1) << 7) + (pass[2] >> 1);
		pass[1] = ((pass[0] & 1) << 7) + (pass[1] >> 1);
		pass[0] = (temp << 7) + (pass[0] >> 1);
		temp = (pass[(counter + 1) & 3] ^ buffer[counter & 7]) >> 2;
		buffer[(counter + 1) & 7] = Lookup_Table[temp & 0x3F] * 2 + buffer[(counter + 1) & 7 ];
		temp = buffer[counter & 7] - pass[(counter + 1) & 3];
		buffer[(counter + 1) & 7] = Lookup_Table[temp & 0x3F] ^ buffer[(counter + 1) & 7];
		buffer[(counter + 1) & 7] = pass[counter & 3] + buffer[(counter + 1) & 7];
	}
}

static void gbox_decryptA(uint8_t *buffer, uint8_t *pass)
{
	int counter;
	uint8_t temp;

	for(counter = 0; counter <= 0x1F; counter++)
	{
		buffer[(counter + 1) & 7] = buffer[(counter + 1) & 7] - pass[counter & 3];
		temp = buffer[counter & 7] - pass[(counter + 1) & 3];
		buffer[(counter + 1) & 7] = Lookup_Table[temp & 0x3F] ^ buffer[(counter + 1) & 7];
		temp = (pass[(counter + 1) & 3] ^ buffer[counter & 7]) >> 2;
		buffer[(counter + 1) & 7] = buffer[(counter + 1) & 7] - Lookup_Table[temp & 0x3F] * 2;
		temp = pass[0] & 0x80;
		pass[0] = ((pass[1] & 0x80) >> 7) + (pass[0] << 1);
		pass[1] = ((pass[2] & 0x80) >> 7) + (pass[1] << 1);
		pass[2] = ((pass[3] & 0x80) >> 7) + (pass[2] << 1);
		pass[3] = (temp >> 7) + (pass[3] << 1);
	}
}

void gbox_encrypt(uint8_t *buffer, int bufsize, uint32_t key)
{
	uint8_t pass[4];
	gbox_convert_pw(&pass[0], key);
	gbox_encryptA(buffer, &pass[0]);
	gbox_encryptB(buffer, bufsize, &pass[0]);
}

void gbox_decrypt(uint8_t *buffer, int bufsize, uint32_t localkey)
{
	uint8_t pass[4];
	gbox_convert_pw(&pass[0], localkey);
	gbox_decryptB(buffer, bufsize, &pass[0]);
	gbox_decryptA(buffer, &pass[0]);
}

void gbox_compress(uint8_t *buf, int32_t unpacked_len, int32_t *packed_len)
{
	uint8_t *tmp, *tmp2;
	lzo_voidp wrkmem;

	if(!cs_malloc(&tmp, 0x40000))
	{
		return;
	}

	if(!cs_malloc(&tmp2, 0x40000))
	{
		NULLFREE(tmp);
		return;
	}

	if(!cs_malloc(&wrkmem, unpacked_len * 0x1000))
	{
		NULLFREE(tmp);
		NULLFREE(tmp2);
		return;
	}

	unpacked_len -= 12;
	memcpy(tmp2, buf + 12, unpacked_len);
	lzo_init();
	lzo_uint pl = 0;

	if(lzo1x_1_compress(tmp2, unpacked_len, tmp, &pl, wrkmem) != LZO_E_OK)
		{ cs_log("compression failed!"); }

	memcpy(buf + 12, tmp, pl);
	pl += 12;
	NULLFREE(tmp);
	NULLFREE(tmp2);
	NULLFREE(wrkmem);
	*packed_len = pl;
}

void gbox_decompress(uint8_t *buf, int32_t *unpacked_len)
{
	uint8_t *tmp;
	if(!cs_malloc(&tmp, 0x40000))
		{ return; }

	int err;
	int len = *unpacked_len - 12;
	*unpacked_len = 0x40000;
	lzo_init();

	if((err = lzo1x_decompress_safe(buf + 12, len, tmp, (lzo_uint *)unpacked_len, NULL)) != LZO_E_OK)
		{ cs_log_dbg(D_READER, "gbox: decompression failed! errno=%d", err); }

	memcpy(buf + 12, tmp, *unpacked_len);
	*unpacked_len += 12;
	NULLFREE(tmp);
}
#endif