73 lines
1.9 KiB
C
Executable File
73 lines
1.9 KiB
C
Executable File
#define MODULE_LOG_PREFIX "emu"
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#include "globals.h"
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#ifdef WITH_EMU
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#include "module-emulator-osemu.h"
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#include "module-emulator-omnicrypt.h"
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#include "oscam-aes.h"
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#include "oscam-string.h"
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static inline int8_t get_ecm_key(uint16_t provider, uint8_t parity, uint8_t *key)
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{
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return emu_find_key('O', provider, 0, parity == 0 ? "00" : "01", key, 16, 1, 0, 0, NULL);
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}
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int8_t omnicrypt_ecm(uint8_t *ecm, uint8_t *dw)
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{
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uint8_t section_syntax_indicator, session_key[16], session_key_parity, position;
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uint16_t private_section_length, session_key_id, payload_length;
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struct aes_keys aes;
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section_syntax_indicator = ecm[1] >> 7;
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if (section_syntax_indicator != 0) // The private_data_bytes immediately follow the private_section_length field
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{
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cs_log("ECM section syntax indicator %d not supported", section_syntax_indicator);
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return EMU_NOT_SUPPORTED;
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}
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private_section_length = b2i(2, ecm + 1) & 0x0FFF;
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if (private_section_length != 0x2D)
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{
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cs_log("ECM has an unsupported private section length of %d", private_section_length);
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return EMU_NOT_SUPPORTED;
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}
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session_key_parity = ecm[3] & 0x01;
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session_key_id = b2i(2, ecm + 4);
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if (!get_ecm_key(session_key_id, session_key_parity, session_key))
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{
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return EMU_KEY_NOT_FOUND;
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}
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aes_set_key(&aes, (char *)session_key);
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payload_length = b2i(2, ecm + 6) & 0x0FFF;
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if (payload_length != 0x28)
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{
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cs_log("ECM has an unsupported payload length of %d", payload_length);
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return EMU_NOT_SUPPORTED;
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}
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for (position = 8; position + 1 < payload_length; position += 4 + 16) // Run twice for odd, even CW
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{
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uint8_t parity = ecm[position + 1] & 0x01;
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uint8_t length = ecm[position + 3];
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if (length != 16)
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{
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cs_log("CW %d has an unsupported length of %d", parity, length);
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return EMU_NOT_SUPPORTED;
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}
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aes_decrypt(&aes, ecm + position + 4, 16);
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memcpy(dw + parity * 8, ecm + position + 4, 8); // Copy the first 8 bytes (rest are zeros)
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}
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return EMU_OK;
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}
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#endif // WITH_EMU
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