libaos.h - aos-tools - Entertainment _our_ way

Source path: svn/ trunk/ libaos/ libaos.h

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/*
 * Written by EiNSTeiN_
 * 		http://archos.g3nius.org/
 *
 * Released under the GNU General Public License v2
 * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
*/

#ifndef __LIBAOS_H
#define __LIBAOS_H

#include <stdint.h>

#include <openssl/rsa.h>
#include <openssl/aes.h>

/* Defines */

#define AOS_MAGIC				0x32534F41	// AOS2

// Signature blocks
#define AOS_TYPE_SIG0			0x30474953	// SIG0
#define AOS_TYPE_SIG1			0x31474953	// SIG1
#define AOS_TYPE_SIG2			0x32474953	// SIG2
#define AOS_TYPE_SIG3			0x33474953	// SIG3
#define AOS_TYPE_SIG4			0x34474953	// SIG4

// Header Blocks
#define AOS_TYPE_CIPHER		0x48504943	// CIPH
#define AOS_TYPE_UNIT			0x54494E55	// UNIT
#define AOS_TYPE_VERSION		0x53524556	// VERS
#define AOS_TYPE_DURATION		0x454d4954	// TIME

// Flash memory
#define AOS_TYPE_FLASH			0x48534c46	// FLSH
#define AOS_TYPE_MTD			0x4644544d	// MTDF

// File operations
#define AOS_TYPE_COPY			0x59504F43	// COPY
#define AOS_TYPE_DELETE		0x54454c44	// DLET
#define AOS_TYPE_MOVE			0x45564f4d	// MOVE
#define AOS_TYPE_SHELL			0x4c454853	// SHEL

// Boolean blocks
#define AOS_TYPE_BOOT			0x544f4f42	// BOOT
#define AOS_TYPE_ADEL			0x4c454441	// ADEL

// Unknown for now
#define AOS_TYPE_GULP			0x47554c50	// GULP
#define AOS_TYPE_FPAR			0x46504152	// FPAR
#define AOS_TYPE_PARM			0x5041524d	// PARM
#define AOS_TYPE_FRMT			0x46524d54	// FRMT
#define AOS_TYPE_PLUG			0x504c5547	// PLUG
#define AOS_TYPE_HDDL			0x4844444c	// HDDL
#define AOS_TYPE_MSGB			0x4d534742	// MSGB

#define AOS_SIGNATURE_LENGTH	128

// Block numbers for AOS2 mandatory blocks
#define AOS_SIGN_BLOCK_ID		0
#define AOS_CIPHER_BLOCK_ID	1
#define AOS_UNIT_BLOCK_ID		2
#define AOS_VERSION_BLOCK_ID	3
#define AOS_DURATION_BLOCK_ID	4

// Magic numbers for various AOS-related files
#define AOS_ZMfX_MAGIC		0x58664D5A // ZMfX
#define AOS_KERNEL_MAGIC		0xDAE589F0
#define AOS_CRAMFS_MAGIC		0xd3c284d5
#define AOS_CIPHER_MAGIC		0xBF959

#define AOS_GZIP_MAGIC			0x08088B1F
#define AOS_GZIP_NONAME_MAGIC	0x00088B1F
#define AOS_GZIP_NONAME_MASK	0x00ffffffff

/* Structures */

struct aos_block {
	uint32_t type;
	uint32_t length;
	uint8_t data[];
} __attribute__((packed));

struct aos_block_signature {
	uint8_t data[AOS_SIGNATURE_LENGTH];
} __attribute__((packed));

struct aos_block_cipher {
	uint32_t magic;
	uint8_t data[AES_BLOCK_SIZE];
} __attribute__((packed));

struct aos_block_unit {
	char product_name[16];
	char product_key[14];
} __attribute__((packed));

struct aos_block_version {
	uint32_t major;
	uint32_t minor;
	uint32_t build;
} __attribute__((packed));

struct aos_block_duration {
	uint32_t count;
	uint32_t time[100];
} __attribute__((packed));

struct aos_block_flash {
	uint32_t offset;
	uint32_t size;
	uint8_t data[];
} __attribute__((packed));

struct aos_block_mtd {
	uint8_t name[256];
	uint32_t offset;
	uint32_t size;
	uint8_t data[];
} __attribute__((packed));

struct aos_block_copy {
	uint32_t partition;
	uint8_t name[256];
	uint32_t size;
	uint8_t data[];
} __attribute__((packed));

#define AOS_PARTITION_SYSTEM	0
#define AOS_PARTITION_DATA		1
#define AOS_PARTITION_CRAMFS	2 // For .cramfs.secure files, on the A5IT only

struct aos_block_delete {
	uint32_t partition;
	uint8_t name[256];
} __attribute__((packed));

struct aos_block_boot {
	uint32_t value;
} __attribute__((packed));

struct aos_block_adel {
	uint32_t value;
} __attribute__((packed));

struct aos_block_shell {
	uint32_t length;
	uint8_t data[];
} __attribute__((packed));


struct aos_signature {
	uint8_t data[AOS_SIGNATURE_LENGTH];
	RSA *rsa;
} __attribute__((packed));

struct aos_encryption {
	AES_KEY key;
	uint8_t iv[AES_BLOCK_SIZE];
} __attribute__((packed));

struct aos_file {
	uint8_t *data;
	unsigned int length; // file length
} __attribute__((packed));

struct flash_header {
	uint32_t magic;
	uint32_t bits;
	uint8_t signature[AOS_SIGNATURE_LENGTH];
	uint32_t unk_88; // data is signed from here to eof
	uint32_t filesize; // size of the file: always populated
	uint32_t entrypoint; // address of the file's entry point: in boot1 this
						// is typically 0x87e80100, in cramfs files this is 0x100,
						// in init/recovery kernel this is not populated
	uint32_t cpio; // offset to the .cpio.gz file: populated only in init/recovery kernel
	uint32_t cpio_size; // size of the .cpio.gz file
	uint32_t unk_9C[25];
	uint8_t data[];
} __attribute__((packed));

struct flash_file {
	struct flash_header *header;
	unsigned int length; // file length
} __attribute__((packed));

/* AOS generic functions */

// Create an aos_file structure
struct aos_file *aos_create(uint8_t *data, unsigned int length);
void aos_free(struct aos_file *file);

// Return 0 if the magic is not AOS2
int aos_verify_magic(struct aos_file *file);

// Return 1 if the signature on the file is valid.
int aos_verify_signature(struct aos_file *file, const uint8_t *mpk_key);

// Return 1 if the aos file is encrypted.
int aos_is_encrypted(struct aos_file *file);

// Decrypt an encrypted aos file.
int aos_decrypt_file(struct aos_file *file, const uint8_t *aes_key);

// Encrypt a plain aos file.
int aos_encrypt_file(struct aos_file *file, const uint8_t *aes_key);

// Detect the key used to sign the aos file and return its index in *device.
int aos_detect_key(struct aos_file *file, uint8_t **keys, unsigned int n, int *device);

// Return 0 if the signature data is all zeroes.
int aos_is_signed(struct aos_file *file);

// Clear the signature from an aos file SIGN block.
int flash_clear_signature(struct flash_file *file);

/* FLASH partitions generic functions */

// Create a flash_file structure
struct flash_file *flash_create(uint8_t *data, unsigned int length);
void flash_free(struct flash_file *file);

// Return 1 if the signature on the flash partition is valid.
int flash_verify_signature(struct flash_file *file, const uint8_t *mpk_key);

// Detect the key used to sign the flash file and return its index in *device.
int flash_detect_key(struct flash_file *file, uint8_t **keys, unsigned int n, int *device);

// Return 0 if the signature data is all zeroes.
int flash_is_signed(struct flash_file *file);

// Clear the signature from a flash segment header
int flash_clear_signature(struct flash_file *file);

 /* Block functions for AOS files */

// return the first block in the file
struct aos_block *block_first(struct aos_file *file);

// Move the block pointer to the next block
struct aos_block *block_next(struct aos_file *file, struct aos_block *block);

// Return 0 if the block's length is longer than the size of the file
int block_is_valid(struct aos_file *file, struct aos_block *block);

// Get a block by its number.
struct aos_block *block_get(struct aos_file *file, int num);

// Return the offset of the current block, counting from the start 
// of the data buffer passed to aos_create()
unsigned int block_offset(struct aos_file *file, struct aos_block *block);

// Append a new block to the aos file
struct aos_block *aos_append_block(struct aos_file *file, uint32_t type, unsigned int length);
struct aos_block *aos_append_block_nopadding(struct aos_file *file, uint32_t type, unsigned int length);

/* Crypto functions */

// Parse the signature block and extract data from it.
int aos_signature_set_data(struct aos_signature *sign, const uint8_t *sig_data);

// Set the decryption key data.
int aos_signature_set_decrypt_key(struct aos_signature *sign, const uint8_t *mpk_data);

// Set the encryption key data.
int aos_signature_set_encrypt_key(struct aos_signature *sign, const uint8_t *mpk_data);

// Verify the signature of the file. 
int aos_signature_check(struct aos_signature *sign, const uint8_t *data, unsigned int length);

// Parse the encryption block and extract the iv from it.
int aos_cipher_set_iv(struct aos_encryption *enc, const uint8_t *iv);

// Set the aes key data. Data must be AOS_BLOCK_SIZE, or 16 bytes long.
int aos_cipher_set_key(struct aos_encryption *enc, const uint8_t *aes_data);

// Return the decrypted data from *in
uint8_t *aos_cipher_decrypt(struct aos_encryption *enc, const uint8_t *in, unsigned int length);

// Return the encrypted data from *in
uint8_t *aos_cipher_encrypt(struct aos_encryption *enc, const uint8_t *in, unsigned int length);

#endif /* __LIBAOS_H */

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Change log

r16 by EiNSTeiN.1337 on Dec 18, 2009 Diff

- Added functions to clear signatures from
aos files and flash segments
- Minor changes in constants and struct
member names

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Older revisions

r14 by EiNSTeiN.1337 on Dec 14, 2009 Diff

Added routine to detect if a flash
segment is signed.

r12 by EiNSTeiN.1337 on Nov 27, 2009 Diff

Added support for unsigned bootloader
parts in firmware
Added support for SHEL blocks

r9 by EiNSTeiN.1337 on Nov 18, 2009 Diff

libaos: Added logic for re-encrypting
an aos file
aos-repack: Added support for writing
a dummy duration block

...

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