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Add MOD0 generation and dynstr/dynsym information to NROs
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@roblabla
roblabla committed Apr 10, 2020
1 parent c32c582 commit 70bb43e
Showing 1 changed file with 135 additions and 43 deletions.
178 changes: 135 additions & 43 deletions src/format/nxo.rs
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Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
use elf;
use elf::types::{EM_ARM, EM_AARCH64, ProgramHeader, PT_LOAD, SHT_NOTE, Machine};
use elf::types::{EM_ARM, EM_AARCH64, ProgramHeader, PT_LOAD, SHT_NOTE, Machine, SectionHeader};
use crate::format::{utils, romfs::RomFs, nacp::NacpFile, npdm::KernelCapability};
use std;
use std::fs::File;
Expand All @@ -9,7 +9,7 @@ use std::path::{Path, PathBuf};
use std::process;
use serde_derive::{Serialize, Deserialize};
use crate::format::utils::HexOrNum;
use std::convert::TryFrom;
use std::convert::{TryFrom, TryInto};

// TODO: Support switchbrew's embedded files for NRO
pub struct NxoFile {
Expand All @@ -19,6 +19,10 @@ pub struct NxoFile {
rodata_segment: ProgramHeader,
data_segment: ProgramHeader,
bss_segment: Option<ProgramHeader>,
eh_frame_hdr_section: Option<SectionHeader>,
dynamic_section: Option<SectionHeader>,
dynstr_section: Option<SectionHeader>,
dynsym_section: Option<SectionHeader>,
build_id: Option<Vec<u8>>,
}

Expand Down Expand Up @@ -68,6 +72,32 @@ where
Ok(())
}

fn write_mod0<T>(nxo_file: &NxoFile, output_writter: &mut T, bss_addr: u32, bss_size: u32) -> std::io::Result<()>
where
T: Write,
{
// MOD magic
output_writter.write_all(b"MOD0")?;
// Dynamic Offset
output_writter.write_u32::<LittleEndian>(nxo_file.dynamic_section.as_ref().map(|v| v.addr as u32).unwrap_or(0))?;

// BSS Start Offset
output_writter.write_u32::<LittleEndian>(bss_addr)?;
// BSS End Offset
output_writter.write_u32::<LittleEndian>(bss_addr + bss_size)?;

let (eh_frame_hdr_addr, eh_frame_hdr_size) = nxo_file.eh_frame_hdr_section.as_ref().map(|v| (v.addr, v.size)).unwrap_or((0, 0));
// EH Frame Header Start
output_writter.write_u32::<LittleEndian>(eh_frame_hdr_addr as u32)?;
// EH Frame Header End
output_writter.write_u32::<LittleEndian>(eh_frame_hdr_addr as u32 + eh_frame_hdr_size as u32)?;

// RTLD ptr - written at runtime by RTLD
output_writter.write_u32::<LittleEndian>(0)?;

Ok(())
}

impl NxoFile {
pub fn from_elf(input: &str) -> std::io::Result<Self> {
let path = PathBuf::from(input);
Expand Down Expand Up @@ -107,23 +137,33 @@ impl NxoFile {
}
None => None,
};
let build_id = sections
.into_iter()
.filter(|&x| {
if x.shdr.shtype == SHT_NOTE {
let mut data = Cursor::new(x.data.clone());
// Ignore the two first offset of nhdr32
data.seek(SeekFrom::Start(0x8)).unwrap();
let n_type = data.read_u32::<LittleEndian>().unwrap();

// BUILD_ID
n_type == 0x3
} else {
false

let mut build_id = None;
let mut dynamic_section = None;
let mut dynstr_section = None;
let mut dynsym_section = None;
let mut eh_frame_hdr_section = None;

for section in sections {
if section.shdr.shtype == SHT_NOTE {
let mut data = Cursor::new(section.data.clone());
// Ignore the two first offset of nhdr32
data.seek(SeekFrom::Start(0x8)).unwrap();
let n_type = data.read_u32::<LittleEndian>().unwrap();

// BUILD_ID
if n_type == 0x3 {
build_id = Some(data.into_inner());
}
})
.map(|section| section.data.clone())
.next();
}
match &*section.shdr.name {
".dynamic" => dynamic_section = Some(section.shdr.clone()),
".dynstr" => dynstr_section = Some(section.shdr.clone()),
".dynsym" => dynsym_section = Some(section.shdr.clone()),
".eh_frame_hdr" => eh_frame_hdr_section = Some(section.shdr.clone()),
_ => ()
}
}

Ok(NxoFile {
file,
Expand All @@ -133,6 +173,10 @@ impl NxoFile {
data_segment: *data_segment,
bss_segment,
build_id,
dynamic_section,
dynstr_section,
dynsym_section,
eh_frame_hdr_section
})
}

Expand Down Expand Up @@ -169,11 +213,11 @@ impl NxoFile {

// NRO magic
output_writter.write_all(b"NRO0")?;
// Unknown
// Version
output_writter.write_u32::<LittleEndian>(0)?;
// Total size
output_writter.write_u32::<LittleEndian>(total_len)?;
// Unknown
// Flags
output_writter.write_u32::<LittleEndian>(0)?;

// Segment Header (3 entries)
Expand All @@ -186,19 +230,21 @@ impl NxoFile {
file_offset += code_size;

// .rodata segment
let rodata_offset = file_offset;
let rodata_size = rodata.len() as u32;
output_writter.write_u32::<LittleEndian>(file_offset)?;
output_writter.write_u32::<LittleEndian>(rodata_size)?;
file_offset += rodata_size;

// .data segment
let data_offset = file_offset;
let data_size = data.len() as u32;
output_writter.write_u32::<LittleEndian>(file_offset)?;
output_writter.write_u32::<LittleEndian>(data_size)?;
file_offset += data_size;

// BSS size
match self.bss_segment {
let (bss_start, bss_size) = match self.bss_segment {
Some(segment) => {
if segment.vaddr != u64::from(file_offset) {
println!(
Expand All @@ -207,6 +253,7 @@ impl NxoFile {
}
output_writter
.write_u32::<LittleEndian>(((segment.memsz + 0xFFF) & !0xFFF) as u32)?;
(segment.vaddr as u32, ((segment.memsz + 0xFFF) & !0xFFF) as u32)
}
_ => {
// in this case the bss is missing or is embedeed in .data. libnx does that, let's support it
Expand All @@ -217,24 +264,65 @@ impl NxoFile {
0
};
output_writter.write_u32::<LittleEndian>(bss_size)?;
(data_segment.vaddr as u32 + data_segment.memsz as u32, bss_size)
}
}
// Unknown
};

// Reserved
output_writter.write_u32::<LittleEndian>(0)?;

write_build_id(&self.build_id, output_writter)?;

// Padding
output_writter.write_u64::<LittleEndian>(0)?;
output_writter.write_u64::<LittleEndian>(0)?;
// TODO: DSO Module Offset (unused)
output_writter.write_u32::<LittleEndian>(0)?;
// Reserved (unused)
output_writter.write_u32::<LittleEndian>(0)?;

// Unknown
output_writter.write_u64::<LittleEndian>(0)?;
// TODO: apiInfo
output_writter.write_u64::<LittleEndian>(0)?;

output_writter.write_all(&code[0x80..])?;
output_writter.write_all(&rodata)?;
output_writter.write_all(&data)?;
// .dynstr section info
output_writter.write_u32::<LittleEndian>(self.dynstr_section.as_ref().map(|v| u32::try_from(v.addr).unwrap()).unwrap_or(0))?;
output_writter.write_u32::<LittleEndian>(self.dynstr_section.as_ref().map(|v| u32::try_from(v.size).unwrap()).unwrap_or(0))?;

// .dynsym section info
output_writter.write_u32::<LittleEndian>(self.dynsym_section.as_ref().map(|v| u32::try_from(v.addr).unwrap()).unwrap_or(0))?;
output_writter.write_u32::<LittleEndian>(self.dynsym_section.as_ref().map(|v| u32::try_from(v.size).unwrap()).unwrap_or(0))?;

let module_offset = u32::from_le_bytes(code[4..8].try_into().unwrap()) as usize;
if module_offset != 0 && !(
(0x80..code_size).contains(&(module_offset as u32)) ||
(rodata_offset..data_offset).contains(&(module_offset as u32)) ||
(data_offset..file_offset).contains(&(module_offset as u32)))
{
panic!("Invalid module offset {}", module_offset)
}

if (0x80..code_size).contains(&(module_offset as u32)) && &code[module_offset..module_offset + 4] != b"MOD0" {
output_writter.write_all(&code[0x80..module_offset])?;
write_mod0(self, output_writter, bss_start, bss_size)?;
output_writter.write_all(&code[module_offset + 0x18..])?;
} else {
output_writter.write_all(&code[0x80..])?;
}

if (rodata_offset..data_offset).contains(&(module_offset as u32)) && &rodata[module_offset - rodata_offset as usize..module_offset - rodata_offset as usize+ 4] == b"MOD0" {
let module_offset = module_offset - rodata_offset as usize;
output_writter.write_all(&rodata[..module_offset])?;
write_mod0(self, output_writter, bss_start, bss_size)?;
output_writter.write_all(&rodata[module_offset + 0x18..])?;
} else {
output_writter.write_all(&rodata)?;
}

if (data_offset..file_offset).contains(&(module_offset as u32)) && &data[module_offset - data_offset as usize..module_offset - data_offset as usize + 4] == b"MOD0" {
let module_offset = module_offset - data_offset as usize;
output_writter.write_all(&data[..module_offset])?;
write_mod0(self, output_writter, bss_start, bss_size)?;
output_writter.write_all(&data[module_offset + 0x18..])?;
} else {
output_writter.write_all(&data)?;
}

// Early return if there's no need for an ASET segment.
if let (None, None, None) = (&icon, &romfs, &nacp) {
Expand Down Expand Up @@ -321,9 +409,9 @@ impl NxoFile {

// NSO magic
output_writter.write_all(b"NSO0")?;
// Unknown
// Version
output_writter.write_u32::<LittleEndian>(0)?;
// Unknown
// Reserved
output_writter.write_u32::<LittleEndian>(0)?;

// Flags, set compression + sum check
Expand All @@ -340,7 +428,7 @@ impl NxoFile {
output_writter.write_u32::<LittleEndian>(text_segment.vaddr as u32)?;
output_writter.write_u32::<LittleEndian>(code_size as u32)?;

// Module offset (TODO: SUPPORT THAT)
// TODO: Module Name Offset
output_writter.write_u32::<LittleEndian>(0)?;

file_offset += compressed_code_size;
Expand All @@ -353,7 +441,7 @@ impl NxoFile {
output_writter.write_u32::<LittleEndian>(rodata_segment.vaddr as u32)?;
output_writter.write_u32::<LittleEndian>(rodata_size as u32)?;

// Module file size (TODO: SUPPORT THAT)
// TODO: Module Name Size
output_writter.write_u32::<LittleEndian>(0)?;

file_offset += compressed_rodata_size;
Expand Down Expand Up @@ -394,16 +482,20 @@ impl NxoFile {
output_writter.write_u32::<LittleEndian>(compressed_rodata_size)?;
output_writter.write_u32::<LittleEndian>(compressed_data_size)?;

// Padding (0x24)
output_writter.write_u64::<LittleEndian>(0)?;
// Reserved (0x1C)
output_writter.write_u32::<LittleEndian>(0)?;
output_writter.write_u64::<LittleEndian>(0)?;
output_writter.write_u64::<LittleEndian>(0)?;
output_writter.write_u64::<LittleEndian>(0)?;
output_writter.write_u32::<LittleEndian>(0)?;

// Unknown
output_writter.write_u64::<LittleEndian>(0)?;
// TODO: SegmentHeaderRelative for .api_info
output_writter.write_u64::<LittleEndian>(0)?;
// SegmentHeaderRelative for .dynstr
output_writter.write_u32::<LittleEndian>(self.dynstr_section.as_ref().map(|v| u32::try_from(v.addr).unwrap()).unwrap_or(0))?;
output_writter.write_u32::<LittleEndian>(self.dynstr_section.as_ref().map(|v| u32::try_from(v.size).unwrap()).unwrap_or(0))?;
// SegmentHeaderRelative for .dynsym
output_writter.write_u32::<LittleEndian>(self.dynsym_section.as_ref().map(|v| u32::try_from(v.addr).unwrap()).unwrap_or(0))?;
output_writter.write_u32::<LittleEndian>(self.dynsym_section.as_ref().map(|v| u32::try_from(v.size).unwrap()).unwrap_or(0))?;

// .text sha256
let text_sum = utils::calculate_sha256(&code)?;
Expand Down Expand Up @@ -501,9 +593,9 @@ impl NxoFile {
output_writer.write_all(&vec![0xFF; (0x20 - caps.len()) * 4])?;

// Section data
output_writer.write_all(&text_data);
output_writer.write_all(&rodata_data);
output_writer.write_all(&data_data);
output_writer.write_all(&text_data)?;
output_writer.write_all(&rodata_data)?;
output_writer.write_all(&data_data)?;

Ok(())
}
Expand Down

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