SELF - SPRX

SELF stands for Signed Executable and Linkable Format. SELF is the file format used by the executables on the PS3 and PS Vita. SPRX stands for Signed Playstation Relocatable eXecutable. SPRX is a file extension, derived from PRX, of SELF files that are loaded as "libraries" rather than "applications". SELF files of applications are often named "EBOOT.BIN" as in "encrypted BOOT.BIN" as a legacy of PS1, PS2 and PSP executables filenames.

Introduction

SELF consists of a Certified File header with an Extended Header followed by the encapsulated ELF file. ELF sections can be compressed using gzip. A SELF is usually encrypted and signed, but fSELF are unsigned SELFs. ELF sections can be encrypted using AES128 and signed using ECDSA160 or RSA2048 + HMAC-SHA1 or HMAC-SHA256. A SELF has a specific header called Extended header where it stores all the parameters for this program.

• Extended Header

Extended Header consists of information regarding the structure and offsets of the SELF. The first part is in plaintext until the Encryption Root Header.

• Encryption Root Header

Encryption Root Header is encrypted under an AES256CBC layer. It contains key and IV to further decrypt the Certification data using AES128 (CBC or CTR).

• Certification data

Certification Header, Certification Body and CF Signature are encrypted under an AES128 (CBC or CTR) layer with the Encryption Root Header key and IV.

• Certification Header

Signature is an ECDSA160/RSA2048 signature of the SHA1/SHA256 digest of the SELF file starting at offset 0 and ending at offset sign_offset.

• Data Segments

Data segments can be encrypted and/or compressed. SHA1/HMAC-SHA1/HMAC-SHA256 is used to ensure that they have not been modified.

Cryptography

Here is a small summary on how the SELF cryptography works.

Basically here are the steps being involved by the loaders:

Loaders all have a static key and iv called respectively erk and riv. Those are keys for the first decryption step which is to decrypt the Encryption Root Header using AES256CBC. When the SELF is protected by NPDRM ?instead of using static keys?, erk and riv are derived by decrypting klicensee using "NP_klic_key".

Then the result is used as key and iv to decrypt the rest of the Certification data using AES128CTR (PS3) or AES128CBC (PS Vita). Finally the decrypted Certification data contains the key and iv for each data segments which are still decrypted following the Segment Certification Header information. This security model is based on the fact that the Certification Root Header once decrypted by the static AES256CBC key in the loader should never be the same from one binary to the other. The same goes for any other value used as an AES128 key or iv.

Loaders are also involved with inflating the binaries using zlib.

The SELF authenticity is based on other independent steps, HMAC-SHA1 or HMAC-SHA256 of the data segments and ECDSA160 or RSA2048 for the signature of the header and the Certification data.

Short references

• AES
• Block cipher modes of operation
• HMAC-SHA1
• ECDSA

More indepth Online course about encryption in generic (also AES/ECDSA): Lecture Notes on Computer and Network Security by Avinash Kak

fSELF

fSELF stands for fake signed ELF. It is the format output by Software Development Kits and ran on activated TestKits and DevKits. As it name suggests, a fSELF is not signed and usually not encrypted. If a fSELF was signed, that would imply that SDK embeds the private keys required to sign it.

A fSELF has Attribute set to 0x8000. ?always?

A fSELF has usually less rights than a System SELF but more than a finalized Non-System SELF. The OS recognizes a fSELF by looking at its program-authority-id.

To document more...

Location

PS3

Files with extensions: eboot.bin, *.self, *.sprx.

See also SELFs inside ELFs.

PS Vita

Files with extensions: eboot.bin, *.self, *.suprx, *.skprx, *.skarx.

File Format

Notes:

• Warning: PS3 uses big endian, PS Vita uses little endian.
• Encapsulated ELF header fields are useless (only the EI_CLASS EI_DATA and EI_VERSION fields are checked).

PS3 early Program Type 3 SELFs

SDK 0.60: No sce version nor elf digest
SDK 0.8X: No sce version, with 0x30 elf digest
SDK 0.9X: With sce version and 0x40 elf digest (scetool produces this type)

Special SELF samples

Warhawk public beta release 012

Oldest official game SELF (although not even NPDRM protected!!!) found by now: 2007-06-08.

• https://web.archive.org/web/*/http://download-prod.online.scea.com/medius-patch/warhawk-pubeta/warhawk//*
• https://web.archive.org/web/20070711084313/http://download-prod.online.scea.com/medius-patch/warhawk-*pubeta/warhawk/20070608_r012/NPUA80093_113_release.self
• https://web.archive.org/web/20070711084217/http://download-prod.online.scea.com/medius-patch/warhawk-pubeta/warhawk/20070608_r012/NPUA80093_113_PARAM.sfo
• https://web.archive.org/web/20070621155928/http://download-prod.online.scea.com/medius-patch/warhawk-pubeta/warhawk/20070608_r012/NPUA80093.cfg

• https://twitter.com/Mathieulh/status/1057395385319211008?s=20

Extended Header

Extended Header offsets are relative to Certified File start.

Struct

 typedef struct { // Size is 0x50 bytes
  uint64_t ext_hdr_version;
  uint64_t program_identification_hdr_offset;
  uint64_t ehdr_offset;
  uint64_t phdr_offset;
  uint64_t shdr_offset;
  uint64_t segment_ext_hdr_offset;
  uint64_t version_hdr_offset;
  uint64_t supplemental_hdr_offset;
  uint64_t supplemental_hdr_size;
  uint64_t padding;
 } __attribute__((packed)) ext_hdr;

Table

field	offset	type	notes
Extended Header version	0x0	u64	3 for PS3, 4 for PS Vita
Program Identification Header offset	0x8	u64	Offset to Program Identification Header.
ELF Header offset	0x10	u64	Offset to ELF Header.
Program Header offset	0x18	u64	Offset to ELF Program Header.
Section Header offset	0x20	u64	Offset to ELF Section Header.
Segment Extended Header offset	0x28	u64	Offset to Segment Extended Header.
Version Header offset	0x30	u64	Offset to Version Header.
Supplemental Header offset	0x38	u64	Offset to Supplemental Header.
Supplemental Header size	0x40	u64	Size of Supplemental Header.
Padding	0x48	u64

Comments

The real ELF data is located after the Extended Header (see Extended Header size in Certified File Header). It is encrypted, unless Certified File attribute is 0x8000 (fake CF). unfself works by cutting the SCE header from the fSELF and if needed decompressing segments.

Program Identification Header

Temporary name was App Info. Official name is Program Identification Header.

Struct

 typedef struct {
   uint64_t program_authority_id;
   uint32_t program_vender_id;
   uint32_t program_type;
   uint64_t program_sceversion;
   uint64_t padding;
 } __attribute__((packed)) program_identification_header;

Table

field	offset	type	notes	example
program_authority_id	0x00	u64	See Program Authority Id	ex: 21 00 00 10 1C CA 01 30
program_vender_id	0x08	u32	See Program Vender Id	ex: 00 00 00 00
program_type	0x0C	u32	See Program Type	ex: 08 00 00 00
program_sceversion	0x10	u64	?SDK version or app version? version ex: 01.02 is translated by make_fself.exe to 02 01 00 00	ex: 0x0000036000000000 (3.600.011), 0x0000009450000000 (0.945.040)
padding	0x18	u64	Padding	00 00 00 00 00 00 00 00

Comments

Aligned to 0x10 bytes.

ELF Header

Struct

PS3

typedef struct {
    uint8_t e_ident[16];              /* ELF identification */
    uint16_t e_type;                  /* object file type */
    uint16_t e_machine;               /* machine type */
    uint32_t e_version;               /* object file version */
    uint64_t e_entry;                 /* entry point address */
    uint64_t e_phoff;                 /* program header offset */
    uint64_t e_shoff;                 /* section header offset */
    uint32_t e_flags;                 /* processor-specific flags */
    uint16_t e_ehsize;                /* ELF header size */
    uint16_t e_phentsize;             /* size of program header entry */
    uint16_t e_phnum;                 /* number of program header entries */
    uint16_t e_shentsize;             /* size of section header entry */
    uint16_t e_shnum;                 /* number of section header entries */
    uint16_t e_shstrndx;              /* section name string table index */
} __attribute__((packed)) ELF;

See also specifications: ELF Header ELF-64 Object File Format

PS Vita

typedef struct {
    uint8_t e_ident[16];              /* ELF identification */
    uint16_t e_type;                  /* object file type */
    uint16_t e_machine;               /* machine type */
    uint32_t e_version;               /* object file version */
    uint32_t e_entry;                 /* entry point address */
    uint32_t e_phoff;                 /* program header offset */
    uint32_t e_shoff;                 /* section header offset */
    uint32_t e_flags;                 /* processor-specific flags */
    uint16_t e_ehsize;                /* ELF header size */
    uint16_t e_phentsize;             /* size of program header entry */
    uint16_t e_phnum;                 /* number of program header entries */
    uint16_t e_shentsize;             /* size of section header entry */
    uint16_t e_shnum;                 /* number of section header entries */
    uint16_t e_shstrndx;              /* section name string table index */
} __attribute__((packed)) ELF;

Name of the variable	Offset	Size	Notes
e_ident[0..3]	0	4	Magic.
e_ident[4]	4	1	Class Type. Must be [ELFCLASS32 = 0x01].
e_ident[5]	5	1	Data Type. Must be [ELFDATA2LSB = 0x01].
e_ident[6]	6	1	File version. Must be 1.
e_ident[7...15]	7	9	unused
e_type	0x10	2	See SCE-specific e_type.
e_machine	0x12	2	Must be [EM_ARM = 0x0028].
e_version	0x14	4	Must be 0x1.
e_entry	0x18	4	Address to jump to in order to start program (warning: not always set).
e_phoff	0x1C	4	Boundary checked, but unused (already given by SELF header). ?and for fSELF?
e_shoff	0x20	4	unused
e_flags	0x24	4	unused
e_ehsize	0x28	2	Must be sizeof(Elf32_Ehdr) = 0x0034.
e_phentsize	0x2A	2	Must be sizeof(Elf32_Phdr) = 0x0020.
e_phnum	0x2C	2	Count of Program Header in this ELF.
e_shentsize	0x2E	2	unused
e_shnum	0x30	2	unused
e_shstrndx	0x32	2	unused

See also yifan lu's outdated specifications for PS Vita fSELF

SCE specific ELF types (e_type)

/* SCE-specific definitions for e_type: */
#define ET_SCE_EXEC		0xFE00		/* SCE Executable - PRX2 */
#define ET_SCE_RELEXEC		0xFE04		/* SCE Relocatable Executable - PRX2 */
#define ET_SCE_STUBLIB		0xFE0C		/* SCE SDK Stubs */
#define ET_SCE_DYNEXEC		0xFE10		/* SCE EXEC_ASLR (PS4 Executable with ASLR) */
#define ET_SCE_DYNAMIC		0xFE18		/* ? */
#define ET_SCE_IOPRELEXEC	0xFF80		/* SCE IOP Relocatable Executable */
#define ET_SCE_IOPRELEXEC2	0xFF81		/* SCE IOP Relocatable Executable Version 2 */
#define ET_SCE_EERELEXEC	0xFF90		/* SCE EE Relocatable Executable */
#define ET_SCE_EERELEXEC2	0xFF91		/* SCE EE Relocatable Executable Version 2 */
#define ET_SCE_PSPRELEXEC	0xFFA0		/* SCE PSP Relocatable Executable */
#define ET_SCE_PPURELEXEC	0xFFA4		/* SCE PPU Relocatable Executable */
#define ET_SCE_ARMRELEXEC	0xFFA5		/* ?SCE ARM Relocatable Executable (PS Vita System Software earlier or equal 0.931.010) */
#define ET_SCE_PSPOVERLAY	0xFFA8		/* ? */

OS ABI identification

#define ELFOSABI_CELL_LV2		102	/* CELL LV2 */

ELF Program Segment Header

Struct

PS3

typedef struct
{
  Elf64_Word	p_type;			/* Segment type */
  Elf64_Word	p_flags;		/* Segment flags */
  Elf64_Off	p_offset;		/* Segment file offset */
  Elf64_Addr	p_vaddr;		/* Segment virtual address */
  Elf64_Addr	p_paddr;		/* Segment physical address */
  Elf64_Xword	p_filesz;		/* Segment size in file */
  Elf64_Xword	p_memsz;		/* Segment size in memory */
  Elf64_Xword	p_align;		/* Segment alignment */
} Elf64_Phdr;

PS Vita

typedef struct
{
  Elf32_Word	p_type;			/* Segment type */
  Elf32_Off	p_offset;		/* Segment file offset */
  Elf32_Addr	p_vaddr;		/* Segment virtual address */
  Elf32_Addr	p_paddr;		/* Segment physical address */
  Elf32_Word	p_filesz;		/* Segment size in file */
  Elf32_Word	p_memsz;		/* Segment size in memory */
  Elf32_Word	p_flags;		/* Segment flags */
  Elf32_Word	p_align;		/* Segment alignment */
} Elf32_Phdr;

See Spec here: ELF Program Segment Header

SCE specific segment types (p_type)

#define PT_SCE_RELA 0x60000000
#define PT_SCE_LICINFO_1 0x60000001
#ddfine PT_SCE_LICINFO_2 0x60000002
#define PT_SCE_DYNLIBDATA 0x61000000
#define PT_SCE_PROCESS_PARAM 0x61000001
#define PT_SCE_MODULE_PARAM 0x61000002
#define PT_SCE_RELRO 0x61000010 // for PS4
#define PT_SCE_COMMENT 0x6FFFFF00
#define PT_SCE_LIBVERSION 0x6FFFFF01
#define PT_SCE_UNK_70000001 0x70000001
#define PT_SCE_IOPMOD 0x70000080
#define PT_SCE_EEMOD 0x70000090
#define PT_SCE_PSPRELA 0x700000A0
#define PT_SCE_PSPRELA2 0x700000A1
#define PT_SCE_PPURELA 0x700000A4
#define PT_SCE_SEGSYM 0x700000A8

PT_SCE_MODULE_PARAM (PS4)

This segment contains a single C struct. It appears instead of PT_SCE_PROCESS_PARAM if the ELF file was compiled to be a library. Like PT_SCE_PROCESS_PARAM, the .data segment contains it and it is always at offset 0.

struct SceModuleParamBase {
    // current size of the struct this version
    uint64_t size;
    // magic bytes
    uint32_t magic; // 0x3c13f4bf
    // current version of the struct format used
    uint32_t version;
    // for example: 0x0803_0001 for firmware version 8.03
    uint32_t sdk_version;
}

The struct is the base or head of the actual struct used. The above fields are always present and their offsets do not change between versions.

Fields whose name are of the form: unk_0x[0-9 aA-fF], are unknown fields whose offset is in the name, e.g. unk_0x18 is at offset 0x18.

// checked FW 2.xx-7.00
// FW < 2.00 files do not have a PT_SCE_MODULE_PARAM segment, unchecked 7.00 < FW < 7.55 
struct SceModuleParamV1 {
    uint64_t size; // 0x18
    uint32_t magic; // 0x3c13f4bf
    uint32_t version; // 1 for V1
    uint32_t sdk_version;
}
// checked 7.55-9.00, unchecked FW > 10.50 and 7.00 < FW < 7.55
struct SceModuleParamV2 {
    uint64_t size; // 0x20
    uint32_t magic; // 0x3c13f4bf
    uint32_t version; // 2 for V2
    uint32_t sdk_version;
    uint64_t unk_0x18;
}

SCE specific segment flags (p_flags)

*PF_SPU_X = 0x00100000
*PF_SPU_W = 0x00200000
*PF_SPU_R = 0x00400000
*PF_RSX_X = 0x01000000
*PF_RSX_W = 0x02000000
*PF_RSX_R = 0x04000000

ELF Section Header

Struct

  typedef struct {
    uint32_t sh_name;                 /* section name */
    uint32_t sh_type;                 /* section type */
    uint64_t sh_flags;                /* section attributes */
    uint64_t sh_addr;                 /* virtual address in memory */
    uint64_t sh_offset;               /* offset in file */
    uint64_t sh_size;                 /* size of section */
    uint32_t sh_link;                 /* link to other section */
    uint32_t sh_info;                 /* miscellaneous information */
    uint64_t sh_addralign;            /* address alignment boundary */
    uint64_t sh_entsize;              /* size of entries, if section has table */
  } __attribute__((packed)) ELF_SHDR;

SCE specific section types (sh_type)

#define SHT_SCE_RELA 0x60000000
#define SHT_SCE_NID 0x61000001
#define SHT_SCE_IOPMOD 0x70000080
#define SHT_SCE_EEMOD 0x70000090
#define SHT_SCE_PSPRELA 0x700000A0
#define SHT_SCE_PPURELA 0x700000A4

Segment Extended Header

Temporary name was Section Info. Official name is segment_ext_header.

Segment Extended Header is a table which maps each phdr/shdr entry to the actual offset/size within the encrypted Certified File. Indeed, because segments can be compressed, they might not match the values listed within the ELF phdr/shdr.

There is one of these entries for each ELF phdr (ELF Program Segment Header) entry in the ELF file so that the console knows where to decrypt the data from, because it might also be compressed.

Struct

typedef struct {
  uint64_t offset;
  uint64_t size;
  uint32_t compression;
  uint32_t unknown;
  uint64_t encryption;
} __attribute__((packed)) segment_ext_header;

Table

field	offset	type	notes
Offset	0x00	u64	Offset to data
Size	0x08	u64	Size of data
compress_algorithm	0x10	u32	1 = plain, 2 = zlib
Unknown	0x14	u32	Always 0, as far as I know.
request_encryption	0x18	u64	0 = unrequested, 1 = completed, 2 = requested

PS3 OS uses the following structure to handle that data:

typedef struct {
  void *data;
  uint64_t size;
  uint64_t offset;
} segment_ext_header;

Version Header

It contains some version information, including an offset to the .sceversion section of the encrypted ELF.

Struct

 typedef struct {
  uint32_t subheader_type; // 1 - sceversion
  uint32_t present;        // 0 = false, 1 = true
  uint32_t size;           // usually 0x10
  uint32_t unknown4;
 } __attribute__((packed)) version_header;

Data Struct

 typedef struct {
  uint16 unknown_1;
  uint16 unknown_2; // 0x1
  uint32 unknown_3;
  uint32 unknown_4; // ?Number of sections?
  uint32 unknown_5;
  ////
    uint64 offset;    // Data offset
    uint64 size;      // Data size
  //// <- these are supposed to be sections
 } SCE_VERSION_DATA_30;

Supplemental Header Table

Temporary name was Control Information. Official name is supplemental_header_table.

Struct

typedef struct ECDSA224_signature { // size is 0x38
   unsigned char r[0x1C];
   unsigned char s[0x1C];
} ECDSA224_signature;

// current hypothesis of SceSharedSecret is full (0x40 bytes) shared_secret overwritten with klicensee at offset 0x10
typedef struct SceSharedSecret { // size is 0x40 on PS Vita SDK versions 0.931.010-3.740.011
   uint8_t shared_secret_0[0x10]; // ex: 0x7E7FD126A7B9614940607EE1BF9DDF5E or full of zeroes
   uint8_t klicensee[0x10]; // usually full of zeroes for NPDRM and fSELF. Usually retrieved from bound RIF for NPDRM.
   uint8_t shared_secret_2[0x10]; // usually full of zeroes for NPDRM and fSELF
   uint32_t shared_secret_3_0; // ex: 0x10, usually full of zeroes for NPDRM and fSELF
   uint32_t shared_secret_3_1; // usually full of zeroes for NPDRM and fSELF
   uint32_t shared_secret_3_2; // usually full of zeroes for NPDRM and fSELF
   uint32_t shared_secret_3_3; // usually full of zeroes for NPDRM and fSELF
} SceSharedSecret;

 typedef struct {
  uint32_t type; // 1=PS3 plaintext_capability; 2=PS3 ELF digest; 3=PS3 NPDRM, 4=PS Vita ELF digest; 5=PS Vita NPDRM; 6=PS Vita boot param; 7=PS Vita shared secret
  uint32_t size;
  uint64_t next; // 1 if another Supplemental Header element follows else 0

  union {
    // type 1, 0x30 bytes
    struct { // 0x20 bytes of data
      plaintext_capability_t plaintext_capability;
    } PS3_plaintext_capability_header;

    // type 2, 0x40 bytes
    struct { // 0x30 bytes of data
      uint8_t constant[0x14]; // same for every PS3/PS Vita SELF, hardcoded in make_fself.exe: 627CB1808AB938E32C8C091708726A579E2586E4
      uint8_t elf_digest[0x14]; // SHA-1. Hash F2C552BF716ED24759CBE8A0A9A6DB9965F3811C is blacklisted by appldr
      uint64_t required_system_version; // filled on Sony authentication server, contains decimal PS3_SYSTEM_VER value from PARAM.SFO
    } PS3_elf_digest_header_40;

    // type 2, 0x30 bytes
    struct { // 0x20 bytes of data
      uint8_t constant_or_elf_digest[0x14];
      uint8_t padding[0xC];
    } PS3_elf_digest_header_30;

    // type 3, 0x90 bytes
    struct { // 0x80 bytes of data
      PS3_NPD npd; // See [[NPD]]
    } PS3_npdrm_header;

     // type 4, 0x50 bytes
     struct { // 0x40 bytes of data
       uint8_t constant[0x14]; // same for every PS3/PS Vita SELF, hardcoded in make_fself.exe: 627CB1808AB938E32C8C091708726A579E2586E4
       uint8_t elf_digest[0x20]; // SHA-256 of source ELF file.
       uint8_t padding[8];
       uint32_t min_required_fw; // ex: 0x363 for 3.63
     } PSVita_elf_digest_header;
     
     // type 5, 0x110 bytes
     struct { // 0x100 bytes of data
       uint32_t magic;               // 7F 44 52 4D (".DRM")
       uint32_t finalized_flag;      // ex: 80 00 00 01. It may be version like in NPD.
       uint32_t drm_type;            // [[NPDRM#DRM_Type]]
       uint32_t padding;             // It may be Application Type like in NPD.
       uint8_t content_id[0x30];
       uint8_t digest[0x10];         // ?sha-1 hash of debug SELF/SPRX created using make_fself_npdrm? content_id hash?
       uint8_t padding_78[0x78];
       ECDSA224_signature sig[0x38]; // signature of PSVita_npdrm_header? signature of an external NPDRM file?
     } PSVita_npdrm_header;
     
     // type 6, 0x110 bytes
     struct { // 0x100 bytes of data
       uint8_t boot_param[0x100];
     } PSVita_boot_param_header;
     
     // type 7, 0x50 bytes
     struct { // 0x40 bytes of data
       SceSharedSecret shared_secret;
     } PSVita_shared_secret_header;
  };
 } __attribute__((packed)) supplemental_header;

Comments

• See Capability_Flags.
• PS3 loader uses supplemental_header_table to handle some data:

typedef struct {
  plaintext_capability_t plaintext_capability;      /* Plaintext Capability */
  uint8[0x14] elf_digest;         /* sha1 hash of the ELF file */
  uint32_t    unknown_0;          /* seems to be padding */
  uint64_t    required_system_version;     /* PS3_SYSTEM_VER, decimal format */
} supplemental_header_table;

Extraction

• Load the Encryption Root Header and decrypt the key and IV entries using AES256CBC with key and IV from OS.
• Load the Certification Header and decrypt it using AES128CTR/CBC with the key and IV entries from the Encryption Root Header.
• Load the Segment Certification Headers and decrypt them using AES128CTR/CBC with the key and ivec entries from the Encryption Root Header.
• Load the Segment Certifications and decrypt them using AES128CTR/CBC with the key and ivec entries from the Encryption Root Header.
• For each Segment Certification:
  • In the SELF file, fseek to data_offset and read in data_size bytes.
  • Decrypt the data using the algorithm, key and ivec from the Segment Certification specified by keyIndex and ivecIndex in the Segment Certification Header.
  • Uncompress the data using the algorithm specified in the Segment Certification Header.
  • Write the output data to the ELF file as the program section specified by segment_id in the Segment Certification Header.

Tools

Official tools

make_fself

make_fself version 1.9.0 (2009-02-15)

Found in SCE PS3 SDK 1.92.

make_fself_npdrm

make_fself_npdrm version 1.9.0 (2009-02-15)

Found in SCE PS3 SDK 1.92.

unfself

unfself version 1.9.0 (2009-02-15)

Found in SCE PS3 SDK 1.92.

Unofficial tools

some tool by geohot (2009)

To be documented.

scetool by fail0verflow (?2010?)

To be documented.

some tool by xorloser

To be documented.