85
edits
Changes
no edit summary
NSO is the main executable format.
NSO is the main executable format.
It starts with a header:
It starts with the "NSO" header and mainly describes .text, .rodata, and .data segments (like a short-form of ELF program headers):
=== SegmentHeader ===
{| class="wikitable" border="1"
{| class="wikitable" border="1"
|-
|-
| 0x0
| 0x0
| 4
| 4
| Magic "NSO0"
| file offset of data
|-
|-
| 0x4
| 0x4
| 4
| 4
|
| memory offset loaded to
|-
|-
| 0x8
| 0x8
| 4
| 4
|
| size of data copied to memory offset (i.e. size after decompression)
|-
|-
| 0xC
| 0xC
| 4
| 4
|
| alignment used on memory size / size of .bss in the case of .data segment
|}
=== .rodata-relative extent ===
{| class="wikitable" border="1"
|-
|-
! Offset
! Size
! Description
|-
|-
| 0x14
| 0x0
| 4
| 4
| .text offset? (0)
| offset (relative to .rodata)
|-
|-
| 0x18
| 0x4
| 4
| 4
| .text size
| size of region
|}
=== NSO Header ===
{| class="wikitable" border="1"
|-
|-
! Offset
! Size
! Description
|-
|-
| 0x20
| 0x0
| 4
| 4
| .rodata LZ4-compressed data start offset
| Magic "NSO0"
|-
|-
| 0x24
| 0x4
| 4
| 4
| .rodata offset
|
|-
|-
| 0x28
| 0x8
| 4
| 4
| .rodata size
|
|-
|-
| 0x2C
| 0xC
| 4
| 4
| .rodata required align? (1)
|
|-
|-
| 0x30
| 0x10
| 4
| 0x10 * 3
| .data LZ4-compressed data start offset
| SegmentHeader for each segment
|-
|-
| 0x40
| 0x40
| 0x14
| 0x14
| SHA1?
| Value of "build id" from ELF's GNU .note section
|-
|-
| 0x54
| 0x54
|-
|-
| 0x60
| 0x60
| 4
| 0x4 * 3
| .rel.dyn compression offset?
| file size of each segment (i.e. LZ4-compressed size)
|-
| 0x6c
| 0x24
| Padding
|-
| 0x90
| 8
| .rodata-relative extents of .dynstr
|-
| 0x98
| 8
| .rodata-relative extents of .dynsym
|-
|-
| 0xA0
| 0xA0
| 0x60
| 0x20 * 3
| SHA256 hashes over the decompressed sections using the above byte-sizes: .text, .rodata, and .data.
| SHA256 hashes over the decompressed sections using the above byte-sizes: .text, .rodata, and .data.
|-
|-