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#[macro_use]
mod gnu_hash;
pub mod header;
pub mod program_header;
pub mod section_header;
#[macro_use]
pub mod sym;
pub mod dyn;
#[macro_use]
pub mod reloc;
pub mod note;
macro_rules! if_sylvan {
($($i:item)*) => ($(
#[cfg(all(feature = "std", feature = "elf32", feature = "elf64", feature = "endian_fd"))]
$i
)*)
}
if_sylvan! {
use scroll::{self, ctx, Pread, Endian};
use strtab::Strtab;
use error;
use container::{Container, Ctx};
pub type Header = header::Header;
pub type ProgramHeader = program_header::ProgramHeader;
pub type SectionHeader = section_header::SectionHeader;
pub type Symtab<'a> = sym::Symtab<'a>;
pub type Sym = sym::Sym;
pub type Dyn = dyn::Dyn;
pub type Dynamic = dyn::Dynamic;
pub type Reloc = reloc::Reloc;
pub type ProgramHeaders = Vec<ProgramHeader>;
pub type SectionHeaders = Vec<SectionHeader>;
pub type ShdrIdx = usize;
#[derive(Debug)]
pub struct Elf<'a> {
pub header: Header,
pub program_headers: ProgramHeaders,
pub section_headers: SectionHeaders,
pub shdr_strtab: Strtab<'a>,
pub dynstrtab: Strtab<'a>,
pub dynsyms: Symtab<'a>,
pub syms: Symtab<'a>,
pub strtab: Strtab<'a>,
pub dynamic: Option<Dynamic>,
pub dynrelas: Vec<Reloc>,
pub dynrels: Vec<Reloc>,
pub pltrelocs: Vec<Reloc>,
pub shdr_relocs: Vec<(ShdrIdx, Vec<Reloc>)>,
pub soname: Option<&'a str>,
pub interpreter: Option<&'a str>,
pub libraries: Vec<&'a str>,
pub is_64: bool,
pub is_lib: bool,
pub entry: u64,
pub bias: u64,
pub little_endian: bool,
ctx: Ctx,
}
impl<'a> Elf<'a> {
pub fn iter_note_headers(&self, data: &'a [u8]) -> Option<note::NoteIterator<'a>> {
let mut iters = vec![];
for phdr in &self.program_headers {
if phdr.p_type == program_header::PT_NOTE {
let offset = phdr.p_offset as usize;
let alignment = phdr.p_align as usize;
iters.push(note::NoteDataIterator {
data,
offset,
size: offset + phdr.p_filesz as usize,
ctx: (alignment, self.ctx)
});
}
}
if iters.is_empty() {
None
} else {
Some(note::NoteIterator {
iters: iters,
index: 0,
})
}
}
pub fn iter_note_sections(
&self,
data: &'a [u8],
section_name: Option<&str>,
) -> Option<note::NoteIterator<'a>> {
let mut iters = vec![];
for sect in &self.section_headers {
if sect.sh_type != section_header::SHT_NOTE {
continue;
}
if section_name.is_some() && !self.shdr_strtab
.get(sect.sh_name)
.map_or(false, |r| r.ok() == section_name) {
continue;
}
let offset = sect.sh_offset as usize;
let alignment = sect.sh_addralign as usize;
iters.push(note::NoteDataIterator {
data,
offset,
size: offset + sect.sh_size as usize,
ctx: (alignment, self.ctx)
});
}
if iters.is_empty() {
None
} else {
Some(note::NoteIterator {
iters: iters,
index: 0,
})
}
}
pub fn is_object_file(&self) -> bool {
self.header.e_type == header::ET_REL
}
pub fn parse(bytes: &'a [u8]) -> error::Result<Self> {
let header = bytes.pread::<Header>(0)?;
let entry = header.e_entry as usize;
let is_lib = header.e_type == header::ET_DYN;
let is_lsb = header.e_ident[header::EI_DATA] == header::ELFDATA2LSB;
let endianness = scroll::Endian::from(is_lsb);
let class = header.e_ident[header::EI_CLASS];
if class != header::ELFCLASS64 && class != header::ELFCLASS32 {
return Err(error::Error::Malformed(format!("Unknown values in ELF ident header: class: {} endianness: {}",
class,
header.e_ident[header::EI_DATA])).into());
}
let is_64 = class == header::ELFCLASS64;
let container = if is_64 { Container::Big } else { Container::Little };
let ctx = Ctx::new(container, endianness);
let program_headers = ProgramHeader::parse(bytes, header.e_phoff as usize, header.e_phnum as usize, ctx)?;
let mut bias: usize = 0;
for ph in &program_headers {
if ph.p_type == program_header::PT_LOAD {
bias = match container {
Container::Little => (::core::u32::MAX - (ph.p_vaddr as u32)).wrapping_add(1) as usize,
Container::Big => (::core::u64::MAX - ph.p_vaddr).wrapping_add(1) as usize,
};
break;
}
}
let mut interpreter = None;
for ph in &program_headers {
if ph.p_type == program_header::PT_INTERP && ph.p_filesz != 0 {
let count = (ph.p_filesz - 1) as usize;
let offset = ph.p_offset as usize;
interpreter = Some(bytes.pread_with::<&str>(offset, ::scroll::ctx::StrCtx::Length(count))?);
}
}
let section_headers = SectionHeader::parse(bytes, header.e_shoff as usize, header.e_shnum as usize, ctx)?;
let get_strtab = |section_headers: &[SectionHeader], section_idx: usize| {
if section_idx >= section_headers.len() {
Ok(Strtab::default())
} else {
let shdr = §ion_headers[section_idx];
shdr.check_size(bytes.len())?;
Strtab::parse(bytes, shdr.sh_offset as usize, shdr.sh_size as usize, 0x0)
}
};
let strtab_idx = header.e_shstrndx as usize;
let shdr_strtab = get_strtab(§ion_headers, strtab_idx)?;
let mut syms = Symtab::default();
let mut strtab = Strtab::default();
for shdr in §ion_headers {
if shdr.sh_type as u32 == section_header::SHT_SYMTAB {
let size = shdr.sh_entsize;
let count = if size == 0 { 0 } else { shdr.sh_size / size };
syms = Symtab::parse(bytes, shdr.sh_offset as usize, count as usize, ctx)?;
strtab = get_strtab(§ion_headers, shdr.sh_link as usize)?;
}
}
let mut soname = None;
let mut libraries = vec![];
let mut dynsyms = Symtab::default();
let mut dynrelas = vec![];
let mut dynrels = vec![];
let mut pltrelocs = vec![];
let mut dynstrtab = Strtab::default();
let dynamic = Dynamic::parse(bytes, &program_headers, bias, ctx)?;
if let Some(ref dynamic) = dynamic {
let dyn_info = &dynamic.info;
dynstrtab = Strtab::parse(bytes,
dyn_info.strtab,
dyn_info.strsz,
0x0)?;
if dyn_info.soname != 0 {
soname = match dynstrtab.get(dyn_info.soname) { Some(Ok(soname)) => Some(soname), _ => None };
}
if dyn_info.needed_count > 0 {
libraries = dynamic.get_libraries(&dynstrtab);
}
let num_syms = if dyn_info.syment == 0 { 0 } else { if dyn_info.strtab <= dyn_info.symtab { 0 } else { (dyn_info.strtab - dyn_info.symtab) / dyn_info.syment }};
dynsyms = Symtab::parse(bytes, dyn_info.symtab, num_syms, ctx)?;
dynrelas = Reloc::parse(bytes, dyn_info.rela, dyn_info.relasz, true, ctx)?;
dynrels = Reloc::parse(bytes, dyn_info.rel, dyn_info.relsz, false, ctx)?;
let is_rela = dyn_info.pltrel as u64 == dyn::DT_RELA;
pltrelocs = Reloc::parse(bytes, dyn_info.jmprel, dyn_info.pltrelsz, is_rela, ctx)?;
}
let shdr_relocs = {
let mut relocs = vec![];
if header.e_type == header::ET_REL {
for (idx, section) in section_headers.iter().enumerate() {
if section.sh_type == section_header::SHT_REL {
section.check_size(bytes.len())?;
let sh_relocs = Reloc::parse(bytes, section.sh_offset as usize, section.sh_size as usize, false, ctx)?;
relocs.push((idx, sh_relocs));
}
if section.sh_type == section_header::SHT_RELA {
section.check_size(bytes.len())?;
let sh_relocs = Reloc::parse(bytes, section.sh_offset as usize, section.sh_size as usize, true, ctx)?;
relocs.push((idx, sh_relocs));
}
}
}
relocs
};
Ok(Elf {
header: header,
program_headers: program_headers,
section_headers: section_headers,
shdr_strtab: shdr_strtab,
dynamic: dynamic,
dynsyms: dynsyms,
dynstrtab: dynstrtab,
syms: syms,
strtab: strtab,
dynrelas: dynrelas,
dynrels: dynrels,
pltrelocs: pltrelocs,
shdr_relocs: shdr_relocs,
soname: soname,
interpreter: interpreter,
libraries: libraries,
is_64: is_64,
is_lib: is_lib,
entry: entry as u64,
bias: bias as u64,
little_endian: is_lsb,
ctx,
})
}
}
impl<'a> ctx::TryFromCtx<'a, (usize, Endian)> for Elf<'a> {
type Error = ::error::Error;
type Size = usize;
fn try_from_ctx(src: &'a [u8], (_, _): (usize, Endian)) -> Result<(Elf<'a>, Self::Size), Self::Error> {
let elf = Elf::parse(src)?;
Ok((elf, src.len()))
}
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn parse_crt1_64bit() {
let crt1: Vec<u8> = include!("../../etc/crt1.rs");
match Elf::parse(&crt1) {
Ok (binary) => {
assert!(binary.is_64);
assert!(!binary.is_lib);
assert_eq!(binary.entry, 0);
assert_eq!(binary.bias, 0);
assert!(binary.syms.get(1000).is_none());
assert!(binary.syms.get(5).is_some());
let syms = binary.syms.to_vec();
let mut i = 0;
assert!(binary.section_headers.len() != 0);
for sym in &syms {
if i == 11 {
let symtab = binary.strtab;
println!("sym: {:?}", &sym);
assert_eq!(&symtab[sym.st_name], "_start");
break;
}
i += 1;
}
assert!(syms.len() != 0);
},
Err (err) => {
println!("failed: {}", err);
assert!(false)
}
}
}
#[test]
fn parse_crt1_32bit() {
let crt1: Vec<u8> = include!("../../etc/crt132.rs");
match Elf::parse(&crt1) {
Ok (binary) => {
assert!(!binary.is_64);
assert!(!binary.is_lib);
assert_eq!(binary.entry, 0);
assert_eq!(binary.bias, 0);
assert!(binary.syms.get(1000).is_none());
assert!(binary.syms.get(5).is_some());
let syms = binary.syms.to_vec();
let mut i = 0;
assert!(binary.section_headers.len() != 0);
for sym in &syms {
if i == 11 {
let symtab = binary.strtab;
println!("sym: {:?}", &sym);
assert_eq!(&symtab[sym.st_name], "__libc_csu_fini");
break;
}
i += 1;
}
assert!(syms.len() != 0);
},
Err (err) => {
println!("failed: {}", err);
assert!(false)
}
}
}
}