SELF

SELF files are a wrapper around encrypted ELF files. The encrypted header contains keys to decrypt each encrypted ELF program, which are decrypted and loaded individually. Because of this, a copy of the ELF headers and ELF program headers are stored in plain text next to the SCE header.

Authority ID

8 Bytes long. Located at offset 0x80 in SELF header.

sceAppMgrConvertVs0UserDrivePath checks the AuthId to limit mount points.

0x2800000000008000 only used by SceWebCore eboot.bin (NPXS10017 / NPXS10037 on 1.69-3.01, replaced later by SceWebKit).

0x2800000000008003 seen used by SceWebCore can access vs0:data/external/cert/ and vs0:data/external/webcore/.

0x210000101CD20007 seen used by PSM can access vs0:data/external and vs0:sys/external.

Relocations

Relocations are stored within the PT_SCE_RELA segment.

Relocation entry format can be one of 10 types which is determined by the first 4 bits.

Format 0

Start	End	Description
0	3	Entry format type set to 0
4	7	Symbol segment index
8	15	Relocation type
16	19	Patch segment index
20	27	Second relocation type
28	31	Distance from offset (used for second relocation)
32	63	Addend
64	95	Offset

Format 1

Start	End	Description
0	3	Entry format type set to 1
4	7	Symbol segment index
8	15	Relocation type
16	19	Patch segment index
20	41	Offset
42	63	Addend

Format 2

Start	End	Description
0	3	Entry format type set to 2
4	7	Symbol segment index
8	15	Relocation type
16	31	Offset
32	64	Addend

Format 3

Start	End	Description
0	3	Entry format type set to 3
4	7	Symbol segment index
8	8	Mode (ARM = 0, THUMB = 1)
9	26	Offset
27	31	Distance from offset
32	64	Addend

Format 4

Start	End	Description
0	3	Entry format type set to 4
4	26	Offset
27	31	Distance from offset

Format 5

Start	End	Description
0	3	Entry format type set to 5
4	12	Distance 1
13	17	Distance 2
18	26	Distance 3
27	31	Distance 4

Format 6

Start	End	Description
0	3	Entry format type set to 6
4	31	Offset

Format 7

Start	End	Description
0	3	Entry format type set to 7
4	10	Offset 1
11	17	Offset 2
18	24	Offset 3
25	31	Offset 4

Format 8

Start	End	Description
0	3	Entry format type set to 8
4	7	Offset 1
8	11	Offset 2
12	15	Offset 3
16	19	Offset 4
20	23	Offset 5
24	27	Offset 6
28	31	Offset 7

Format 9

Start	End	Description
0	3	Entry format type set to 9
4	5	Offset 1
6	7	Offset 2
8	9	Offset 3
10	11	Offset 4
12	13	Offset 5
14	15	Offset 6
16	17	Offset 7
18	19	Offset 8
20	21	Offset 9
22	23	Offset 10
24	25	Offset 11
26	27	Offset 12
28	29	Offset 13
30	31	Offset 14

Supported Relocation Codes (3.60)

Code	Description
0	R_ARM_NONE
2	R_ARM_ABS32
3	R_ARM_REL32
10	R_ARM_THM_CALL
28	R_ARM_CALL
29	R_ARM_JUMP24
38	R_ARM_TARGET1 (same as R_ARM_ABS32)
40	R_ARM_V4BX (same as R_ARM_NONE)
41	R_ARM_TARGET2 (same as R_ARM_REL32)
42	R_ARM_PREL31
43	R_ARM_MOVW_ABS_NC
44	R_ARM_MOVT_ABS
47	R_ARM_THM_MOVW_ABS_NC
48	R_ARM_THM_MOVT_ABS

Encryption

SELF, PRX and Update Packages are all encrypted using the exact same algorithm, while SELF are hashed and signed (signature is RSA based), this section only focuses on the encryption layer itself.

• Step 1

The first step uses a static key and IV contained within a relevant Secure Module; for example update package keys are located in update_service_sm.self while kernel prx keys are located in kprx_auth_sm.self (or, for secure module themselves as well as kernel_boot_loader.self, inside secure_kernel.enp).

The initial step decrypts the first 0x40 bytes of the self metadata using AES256CBC, this results into the key and IV used in step 2

• Step 2

The second step uses the key and iv decrypted from the first 0x40 bytes of the metadata to decrypt the rest of the metadata using AES128CBC.

• Step 3

The SELF metadata is typically stored in this format (below is the metadata example for a 4 sections self): Update packages metadata follows the same principles but is slightly different (different MAGIC/Header)

Offset(h) 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F

00000000  0F F8 FF FF FF FF FF FF FA FF FF FF FB FF FF FF  .øÿÿÿÿÿÿúÿÿÿûÿÿÿ
00000010  18 00 00 00 70 01 00 00 00 00 00 00 00 00 00 00  ....p...........
00000020  00 0A 00 00 00 00 00 00 C0 00 00 00 00 00 00 00  ........À....... <<< First section address
00000030  02 00 00 00 01 00 00 00 06 00 00 00 00 00 00 00  ................
00000040  03 00 00 00 04 00 00 00 05 00 00 00 01 00 00 00  ................
00000050  00 0B 00 00 00 00 00 00 FC B4 07 00 00 00 00 00  ........ü´...... <<< Second section address
00000060  02 00 00 00 02 00 00 00 06 00 00 00 06 00 00 00  ................
00000070  03 00 00 00 0A 00 00 00 0B 00 00 00 01 00 00 00  ................
00000080  00 C0 07 00 00 00 00 00 98 1E 00 00 00 00 00 00  .À......˜....... <<< Third section address
00000090  02 00 00 00 03 00 00 00 06 00 00 00 0C 00 00 00  ................
000000A0  03 00 00 00 10 00 00 00 11 00 00 00 01 00 00 00  ................
000000B0  00 DF 07 00 00 00 00 00 9D BA 02 00 00 00 00 00  .ß.......º...... <<< Fourth section address
000000C0  02 00 00 00 04 00 00 00 06 00 00 00 12 00 00 00  ................
000000D0  03 00 00 00 16 00 00 00 17 00 00 00 01 00 00 00  ................
000000E0  AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA  ªªªªªªªªªªªªªªªª  <<< First Section Hash
000000F0  AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA  ªªªªªªªªªªªªªªªª  <<< First Section Hash
00000100  FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF  ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ
00000110  FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF  ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ
00000120  EE EE EE EE EE EE EE EE EE EE EE EE EE EE EE EE  îîîîîîîîîîîîîîîî  <<< First Section random key
00000130  EE EE EE EE EE EE EE EE EE EE EE EE EE EE EE EE  îîîîîîîîîîîîîîîî  <<< First Section random IV
00000140  BB BB BB BB BB BB BB BB BB BB BB BB BB BB BB BB  »»»»»»»»»»»»»»»»  <<< Second Section Hash
00000150  BB BB BB BB BB BB BB BB BB BB BB BB BB BB BB BB  »»»»»»»»»»»»»»»»  <<< Second Section Hash
00000160  FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF  ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ
00000170  FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF  ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ
00000180  EE EE EE EE EE EE EE EE EE EE EE EE EE EE EE EE  îîîîîîîîîîîîîîîî  <<< Second Section random key
00000190  EE EE EE EE EE EE EE EE EE EE EE EE EE EE EE EE  îîîîîîîîîîîîîîîî  <<< Second Section random IV
000001A0  CC CC CC CC CC CC CC CC CC CC CC CC CC CC CC CC  ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ  <<< Third Section Hash
000001B0  CC CC CC CC CC CC CC CC CC CC CC CC CC CC CC CC  ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ  <<< Third Section Hash
000001C0  FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF  ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ
000001D0  FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF  ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ
000001E0  EE EE EE EE EE EE EE EE EE EE EE EE EE EE EE EE  îîîîîîîîîîîîîîîî  <<< Third Section random key
000001F0  EE EE EE EE EE EE EE EE EE EE EE EE EE EE EE EE  îîîîîîîîîîîîîîîî  <<< Third Section random IV
00000200  DD DD DD DD DD DD DD DD DD DD DD DD DD DD DD DD  ÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝ  <<< Fourth Section Hash
00000210  DD DD DD DD DD DD DD DD DD DD DD DD DD DD DD DD  ÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝÝ  <<< Fourth Section Hash
00000220  FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF  ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ
00000230  FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF  ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ
00000240  EE EE EE EE EE EE EE EE EE EE EE EE EE EE EE EE  îîîîîîîîîîîîîîîî  <<< Fourth Section random key
00000250  EE EE EE EE EE EE EE EE EE EE EE EE EE EE EE EE  îîîîîîîîîîîîîîîî  <<< Fourth Section random IV
00000260  01 00 00 00 30 00 00 00 01 00 00 00 00 00 00 00  ....0...........
00000270  80 00 00 00 C0 00 F0 00 00 00 00 00 FF FF FF FF  €...À.ð.....ÿÿÿÿ  <<< Metadata end

Following the same principles, an update package metadata would look like this:

Offset(h) 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F

00000000  00 02 00 00 00 00 00 00 05 00 00 00 03 00 00 00  ................
00000010  0E 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000020  00 03 00 00 00 00 00 00 40 00 00 00 00 00 00 00  ........@.......
00000030  01 00 00 00 01 00 00 00 06 00 00 00 00 00 00 00  ................
00000040  01 00 00 00 FF FF FF FF FF FF FF FF 01 00 00 00  ....ÿÿÿÿÿÿÿÿ....
00000050  40 03 00 00 00 00 00 00 40 00 00 00 00 00 00 00  @.......@.......
00000060  02 00 00 00 02 00 00 00 06 00 00 00 04 00 00 00  ................
00000070  01 00 00 00 FF FF FF FF FF FF FF FF 01 00 00 00  ....ÿÿÿÿÿÿÿÿ....
00000080  80 03 00 00 00 00 00 00 00 00 80 00 00 00 00 00  €.........€.....
00000090  03 00 00 00 03 00 00 00 06 00 00 00 08 00 00 00  ................
000000A0  03 00 00 00 0C 00 00 00 0D 00 00 00 01 00 00 00  ................
000000B0  AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA  ªªªªªªªªªªªªªªªª  <<< Hash
000000C0  AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA  ªªªªªªªªªªªªªªªª  <<< Hash
000000D0  FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF  ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ  <<< Random key
000000E0  FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF  ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ  <<< Random IV
000000F0  BB BB BB BB BB BB BB BB BB BB BB BB BB BB BB BB  »»»»»»»»»»»»»»»»  <<< Hash
00000100  BB BB BB BB BB BB BB BB BB BB BB BB BB BB BB BB  »»»»»»»»»»»»»»»»  <<< Hash
00000110  FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF  ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ  <<< Random key
00000120  FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF  ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ  <<< Random IV
00000130  CC CC CC CC CC CC CC CC CC CC CC CC CC CC CC CC  ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ  <<< Hash
00000140  CC CC CC CC CC CC CC CC CC CC CC CC CC CC CC CC  ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ  <<< Hash
00000150  FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF  ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ  <<< Random key
00000160  FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF  ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ  <<< Random IV
00000170  FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF  ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ  <<< Random key
00000180  FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF  ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ  <<< Random IV

• Step 4

The last step uses the keys and ivs extracted from the metadata to decrypt their respective sections using AES128CTR.