SELF - SPRX

Source: http://ps3wiki.lan.st/index.php?title=SELF_File_Format_and_Decryption

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File Format

Notes:

• Numbers are stored in big endian format.

SELF Header

typedef struct
{
uint32_t magic;                   // "SCE\0"
uint32_t version;                 // 2
uint16_t attribute;               // 0x8000 - fself
uint16_t category;
uint32_t metadataInfoOffset;
uint64_t fileOffset;
uint64_t fileSize;
uint64_t unknown06;
uint64_t programInfoOffset;
uint64_t elfHeaderOffset;
uint64_t elfProgramHeadersOffset;
uint64_t elfSectionHeadersOffset;
uint64_t sInfoOffset;
uint64_t versionInfoOffset;
uint64_t controlInfoOffset;
uint64_t controlInfoSize;
uint64_t unknown15;
}
SELFHEADER_t;

Program Info

typedef struct
{ 
  uint64_t programAuthId;
  uint64_t unknown01;
  uint16_t programVersion[4];
  uint64_t unknown03;
}
PROGRAMINFO_t;

ELF Header

See Spec here: ELF Header

Notes:

• e_type: ET_PS3PRX=0xFFA4
• EI_OSABI: ELFOSABI_CELL_LV2=0x66

ELF Program Headers

See Spec here: ELF Program Headers

Segment Information

typedef struct
{ 
  uint64_t dataOffset;
  uint64_t dataSize;
  uint32_t compressed;  //1:NO, 2:YES
  uint32_t unknown03;
  uint32_t unknown04;
  uint32_t encrypted;   //0:NA, 1:YES, 2:NO
}
SEGMENTINFO_t;

Notes:

• There is one Segment Information for each ELF Program Header.
  

Control Information

typedef struct
{ 
  uint32_t unknown00;
  uint32_t unknown01;
  uint32_t unknown02;
  uint32_t unknown03;
  uint32_t controlFlags[8];
  uint32_t unknown05;
  uint32_t unknown06;
  uint32_t unknown07;
  uint32_t unknown08;
  char digest[64];
  uint32_t unknown10;
  uint32_t unknown11;
}
CONTROLINFO_t;

Metadata Information

typedef struct
{
  uint8_t unknown00[32];
  uint8_t key[32];
  uint8_t ivec[32];
}
METADATAINFO_t;

Notes:

• The key and ivec fields are encrypted using AES256CBC.
• This is not present if it is an FSELF.

Metadata Header

typedef struct
{
  uint64_t signatureInputLength;
  uint32_t unknown02;
  uint32_t sectionCount;
  uint32_t keyCount;
  uint32_t signatureInfoSize;
  uint32_t unknown06;
  uint32_t unknown07;
}
METADATAHEADER_t;

Notes:

• The metadata header is located after the metadata info in the SELF file.
• It is decrypted using AES128CTR with the key and ivec entries from the metadata information.
• The signature input length is the number of bytes which are used to generate the SHA-1 which is used to generate the ECDSA signature. The length should be eveything from the beginning until the signature itself. The decrypted version of the input data is used.
• This is only present if the metadata Information is present.

Metadata Section Headers

typedef struct
{
  uint64_t dataOffset;
  uint64_t dataSize;
  uint32_t unknown02;
  uint32_t programIndex;
  uint32_t unknown04;
  uint32_t sha1Index;
  uint32_t encrypted;  //1:NO, 3:YES
  uint32_t keyIndex;
  uint32_t ivecIndex;
  uint32_t compressed; //1:NO, 2:YES
}
METADATASECTIONHEADER_t;

Notes:

• The metadata section headers are located after the metadata header in the SELF file.
• The number of sections is indicated by the sectionCount entry in the metadata header.
• They are decrypted using AES128CTR with the key and ivec entries from the metadata information.
• Section data is decrypted using AES128CTR with the key and ivec from the metadata keys specified by keyIndex and ivecIndex.
• Section data will also need to be uncompressed using zlib.
• The dataOffsets of the metadata section headers match in general the segment information dataOffsets.
• This is only present if the metadata header is present.

Metadata Keys

typedef uint8_t METADATAKEY_t [16];

Notes:

• The metadata keys are located after the metadata section headers in the SELF file.
• The number of keys is indicated by the keyCount entry in the metadata header.
• They are decrypted using AES128CTR with the key and ivec entries from the metadata information.
• If the sha1Index points to a key, then key[sha1Index] and key[sha1Index+1] form the 160-bit hash. key[sha1Index+2] to key[key[sha1Index+6] form the 512-bit key for the HMAC-SHA1. The HMAC-SHA1 is calculated on the decrypted data and before the decompression.

Signature Information

typedef struct
{
  uint32_t unknown00;
  uint32_t signatureSize;
  uint64_t unknown02;
  uint64_t unknown03;
  uint64_t unknown04;
  uint64_t unknown05;
  uint32_t unknown06;
  uint32_t unknown07;
}
SIGNATUREINFO_t;

Notes:

• The signature information is located after the metadata keys in the SELF file.
• It is only present if the signatureInfoSize in the metadata header is not zero.
• It is decrypted using AES128CTR with the key and ivec entries from the metadata information.

Signature

typedef struct
{
  uint8_t r[21];
  uint8_t s[21];
  uint8_t padding[6];
}
SIGNATURE_t;

Notes:

• The signature is located after the the signature information in the SELF file.
• It is even present if the signature information is not present.
• It is decrypted using AES128CTR with the key and ivec entries from the metadata information.

Extracting an ELF

ELF Header

Elf64_Ehdr elfHeader;

fseek ( selfFile, fix64 ( selfHeader.elfHeaderOffset ), SEEK_SET );
fread ( &elfHeader, sizeof ( Elf64_Ehdr ), 1, selfFile );

fseek ( elfFile, 0, SEEK_SET );
fwrite ( &elfHeader, sizeof ( Elf64_Ehdr ), 1, elfFile );

Section Headers

Elf64_Shdr elfSectionHeaders[100];

fseek ( selfFile, fix64 ( selfHeader.elfSectionHeadersOffset ), SEEK_SET );
fread ( elfSectionHeaders, sizeof ( Elf64_Shdr ), fix16 ( elfHeader.e_shnum ), selfFile );

fseek ( elfFile, fix64 ( elfHeader.e_shoff ), SEEK_SET );
fwrite ( elfSectionHeaders, sizeof ( Elf64_Shdr ), fix16 ( elfHeader.e_shnum ), elfFile );

Section Data

Notes:

• Unknown, manually copying the data over works for now.
• There should be a section data offset somewhere.

Program Headers

Elf64_Phdr elfProgramHeaders[100];

fseek ( selfFile, fix64 ( selfHeader.elfProgramHeadersOffset ), SEEK_SET );
fread ( elfProgramHeaders, sizeof ( Elf64_Phdr ), fix16 ( elfHeader.e_phnum ), selfFile );

fseek ( elfFile, fix64 ( elfHeader.e_phoff ), SEEK_SET );
fwrite ( elfProgramHeaders, sizeof ( Elf64_Phdr ), fix16 ( elfHeader.e_phnum ), elfFile );

Program Data

Notes:

• Load the metadata information and decrypt the key and ivec entries using AES256CBC using erk and riv.
• Load the metadata header and decrypt it using AES128CTR with the key and ivec entries from the metadata information.
• Load sectionCount metadata section headers and decrypt them using AES128CTR with the key and ivec entries from the metadata information.
• Load keyCount metadata keys and decrypt them using AES128CTR with the key and ivec entries from the metadata information.
• For each metadata section:
  • In the SELF file, fseek to dataOffset and read in dataSize bytes.
  • Decrypt the data using AES128CTR with the key and ivec from the metadata keys specified by keyIndex and ivecIndex from the metadata section header.
  • Uncompress the data using zlib.
  • Write it to the ELF file as the program section specified by sectionIndex in the metadata section header.