/usr/bin/avos:AOS parse cipher()

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Description

Parse the CIPH block, load the 0x10022 key and set some callbacks for reading/seeking in the encrypted .aos file.

References To

• AOS_load_10022()
• AOS_aes_key
• AOS_rsa_file_read()
• AOS_rsa_file_seek()

The Code

char AOS_aes_key[?];
 
int AOS_parse_cipher(int fd) {
	int unk_234;		// -0x234
	char buffer[28];	// -0x22C
	void *ptr;		// -0x01C
	int read;		// -0x018
	char *data_10022;	// -0x014
	int pos;		// -0x010
 
	pos = (uint32_t)ftell64(fd);
	read = fread(fd, &buffer, 28);
	if(read != 28)
		return 247; // failure
 
 
	if(*(uint32_t *)&buffer[0] != 0x43495048) { // CIPH
 
		AOS_file_read_ptr = &fread; // int fread(int fd, char *buffer, int size)
		AOS_file_seek_ptr = &fseek64; // int64_t fseek64(int fd, offset, whence);
 
		fseek64(fd, pos, SEEK_SET);
		return 0; // success
	}
 
	ptr = &buffer[8];
	if((*ptr == 0xBF959) {
		AOS_file_read_ptr = &AOS_rsa_file_read;
		AOS_file_seek_ptr = &AOS_rsa_file_seek;
 
		dword_FF01FC = 0;
		dword_FF0200 = 0;
		dword_FE9F88 = 1;
 
		memcpy(AOS_ciph_data_0, ptr+4, 16);
		memcpy(AOS_ciph_data_1, ptr+4, 16);
 
		data_10022 = AOS_load_10022();
		if(data_10022 == 0)
			return 249; // failure
 
		if(aes_set_key(AOS_aes_key, &data_10022[2], 
				(uint16_t)(data_10022[0] | ((data_10022+1) << 8))) != 0) {
			return 250; // failure
 
		return 0; // success
	}
 
	AOS_file_read_ptr = &fread; // int fread(int fd, char *buffer, int size)
	AOS_file_seek_ptr = &fseek64; // int64_t fseek64(int fd, offset, whence);
 
	return 0;
}