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#[cfg(target_os = "android")]
use crate::linux::android::late_process_mappings;
use crate::{
linux::{
auxv_reader::{AuxvType, ProcfsAuxvIter},
errors::{DumperError, InitError, ThreadInfoError},
maps_reader::{MappingInfo, MappingInfoParsingResult, DELETED_SUFFIX},
thread_info::{Pid, ThreadInfo},
LINUX_GATE_LIBRARY_NAME,
},
minidump_format::GUID,
};
use goblin::elf;
use nix::{
errno::Errno,
sys::{ptrace, wait},
};
use std::{
collections::HashMap,
ffi::c_void,
io::{BufRead, BufReader},
path,
result::Result,
};
#[derive(Debug, Clone)]
pub struct Thread {
pub tid: Pid,
pub name: Option<String>,
}
#[derive(Debug)]
pub struct PtraceDumper {
pub pid: Pid,
threads_suspended: bool,
pub threads: Vec<Thread>,
pub auxv: HashMap<AuxvType, AuxvType>,
pub mappings: Vec<MappingInfo>,
}
#[cfg(target_pointer_width = "32")]
pub const AT_SYSINFO_EHDR: u32 = 33;
#[cfg(target_pointer_width = "64")]
pub const AT_SYSINFO_EHDR: u64 = 33;
impl Drop for PtraceDumper {
fn drop(&mut self) {
let _ = self.resume_threads();
}
}
impl PtraceDumper {
pub fn new(pid: Pid) -> Result<Self, InitError> {
let mut dumper = PtraceDumper {
pid,
threads_suspended: false,
threads: Vec::new(),
auxv: HashMap::new(),
mappings: Vec::new(),
};
dumper.init()?;
Ok(dumper)
}
pub fn init(&mut self) -> Result<(), InitError> {
self.read_auxv()?;
self.enumerate_threads()?;
self.enumerate_mappings()?;
Ok(())
}
#[cfg_attr(not(target_os = "android"), allow(clippy::unused_self))]
pub fn late_init(&mut self) -> Result<(), InitError> {
#[cfg(target_os = "android")]
{
late_process_mappings(self.pid, &mut self.mappings)?;
}
Ok(())
}
pub fn copy_from_process(
child: Pid,
src: *mut c_void,
num_of_bytes: usize,
) -> Result<Vec<u8>, DumperError> {
use DumperError::CopyFromProcessError as CFPE;
let pid = nix::unistd::Pid::from_raw(child);
let mut res = Vec::new();
let mut idx = 0usize;
while idx < num_of_bytes {
let word = ptrace::read(pid, (src as usize + idx) as *mut c_void)
.map_err(|e| CFPE(child, src as usize, idx, num_of_bytes, e))?;
res.append(&mut word.to_ne_bytes().to_vec());
idx += std::mem::size_of::<libc::c_long>();
}
Ok(res)
}
pub fn suspend_thread(child: Pid) -> Result<(), DumperError> {
use DumperError::PtraceAttachError as AttachErr;
use DumperError::PtraceDetachError as DetachErr;
let pid = nix::unistd::Pid::from_raw(child);
ptrace::attach(pid).map_err(|e| AttachErr(child, e))?;
loop {
match wait::waitpid(pid, Some(wait::WaitPidFlag::__WALL)) {
Ok(_) => break,
Err(e @ Errno::EINTR) => {
ptrace::detach(pid, None).map_err(|e| DetachErr(child, e))?;
return Err(DumperError::WaitPidError(child, e));
}
Err(_) => continue,
}
}
#[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
{
let skip_thread;
let regs = ptrace::getregs(pid);
if let Ok(regs) = regs {
#[cfg(target_arch = "x86_64")]
{
skip_thread = regs.rsp == 0;
}
#[cfg(target_arch = "x86")]
{
skip_thread = regs.esp == 0;
}
} else {
skip_thread = true;
}
if skip_thread {
ptrace::detach(pid, None).map_err(|e| DetachErr(child, e))?;
return Err(DumperError::DetachSkippedThread(child));
}
}
Ok(())
}
pub fn resume_thread(child: Pid) -> Result<(), DumperError> {
use DumperError::PtraceDetachError as DetachErr;
let pid = nix::unistd::Pid::from_raw(child);
ptrace::detach(pid, None).map_err(|e| DetachErr(child, e))?;
Ok(())
}
pub fn suspend_threads(&mut self) -> Result<(), DumperError> {
let threads_count = self.threads.len();
self.threads.retain(|x| Self::suspend_thread(x.tid).is_ok());
if self.threads.is_empty() {
Err(DumperError::SuspendNoThreadsLeft(threads_count))
} else {
self.threads_suspended = true;
Ok(())
}
}
pub fn resume_threads(&mut self) -> Result<(), DumperError> {
let mut result = Ok(());
if self.threads_suspended {
for thread in &self.threads {
match Self::resume_thread(thread.tid) {
Ok(_) => {}
x => {
result = x;
}
}
}
}
self.threads_suspended = false;
result
}
fn enumerate_threads(&mut self) -> Result<(), InitError> {
let pid = self.pid;
let filename = format!("/proc/{}/task", pid);
let task_path = path::PathBuf::from(&filename);
if task_path.is_dir() {
std::fs::read_dir(task_path)
.map_err(|e| InitError::IOError(filename, e))?
.into_iter()
.filter_map(|entry| entry.ok())
.filter_map(|entry| {
entry
.file_name()
.to_str()
.and_then(|name| name.parse::<Pid>().ok())
})
.map(|tid| {
let name = std::fs::read_to_string(format!("/proc/{}/task/{}/comm", pid, tid))
.map(|s| s.trim_end().to_string())
.ok();
(tid, name)
})
.for_each(|(tid, name)| self.threads.push(Thread { tid, name }));
}
Ok(())
}
fn read_auxv(&mut self) -> Result<(), InitError> {
let filename = format!("/proc/{}/auxv", self.pid);
let auxv_path = path::PathBuf::from(&filename);
let auxv_file =
std::fs::File::open(auxv_path).map_err(|e| InitError::IOError(filename, e))?;
let input = BufReader::new(auxv_file);
let reader = ProcfsAuxvIter::new(input);
self.auxv = reader
.filter_map(Result::ok)
.map(|x| (x.key, x.value))
.collect();
if self.auxv.is_empty() {
Err(InitError::NoAuxvEntryFound(self.pid))
} else {
Ok(())
}
}
fn enumerate_mappings(&mut self) -> Result<(), InitError> {
let linux_gate_loc = *self.auxv.get(&AT_SYSINFO_EHDR).unwrap_or(&0);
let at_entry;
#[cfg(target_arch = "arm")]
{
at_entry = 9;
}
#[cfg(not(target_arch = "arm"))]
{
at_entry = libc::AT_ENTRY;
}
let entry_point_loc = *self.auxv.get(&at_entry).unwrap_or(&0);
let filename = format!("/proc/{}/maps", self.pid);
let errmap = |e| InitError::IOError(filename.clone(), e);
let maps_path = path::PathBuf::from(&filename);
let maps_file = std::fs::File::open(maps_path).map_err(errmap)?;
for line in BufReader::new(maps_file).lines() {
let line = line.map_err(errmap)?;
match MappingInfo::parse_from_line(&line, linux_gate_loc, self.mappings.last_mut()) {
Ok(MappingInfoParsingResult::Success(map)) => self.mappings.push(map),
Ok(MappingInfoParsingResult::SkipLine) | Err(_) => continue,
}
}
if entry_point_loc != 0 {
let mut swap_idx = None;
for (idx, module) in self.mappings.iter().enumerate() {
if entry_point_loc >= module.start_address.try_into().unwrap()
&& entry_point_loc < (module.start_address + module.size).try_into().unwrap()
{
swap_idx = Some(idx);
break;
}
}
if let Some(idx) = swap_idx {
self.mappings.swap(0, idx);
}
}
Ok(())
}
pub fn get_thread_info_by_index(&self, index: usize) -> Result<ThreadInfo, ThreadInfoError> {
if index > self.threads.len() {
return Err(ThreadInfoError::IndexOutOfBounds(index, self.threads.len()));
}
ThreadInfo::create(self.pid, self.threads[index].tid)
}
pub fn get_stack_info(&self, int_stack_pointer: usize) -> Result<(usize, usize), DumperError> {
let page_size = nix::unistd::sysconf(nix::unistd::SysconfVar::PAGE_SIZE)?
.expect("page size apparently unlimited: doesn't make sense.");
let stack_pointer = int_stack_pointer & !(page_size as usize - 1);
let stack_to_capture = 32 * 1024;
let mapping = self
.find_mapping(stack_pointer)
.ok_or(DumperError::NoStackPointerMapping)?;
let offset = stack_pointer - mapping.start_address;
let distance_to_end = mapping.size - offset;
let stack_len = std::cmp::min(distance_to_end, stack_to_capture);
Ok((stack_pointer, stack_len))
}
pub fn sanitize_stack_copy(
&self,
stack_copy: &mut [u8],
stack_pointer: usize,
sp_offset: usize,
) -> Result<(), DumperError> {
let defaced;
#[cfg(target_pointer_width = "64")]
{
defaced = 0x0defaced0defacedusize.to_ne_bytes();
}
#[cfg(target_pointer_width = "32")]
{
defaced = 0x0defacedusize.to_ne_bytes();
};
let test_bits = 11;
let array_size = 1 << (test_bits - 3);
let array_mask = array_size - 1;
let shift = 32 - 11;
let stack_mapping = self.find_mapping_no_bias(stack_pointer);
let mut last_hit_mapping: Option<&MappingInfo> = None;
let small_int_magnitude: isize = 4096;
let mut could_hit_mapping = vec![0; array_size];
for mapping in &self.mappings {
if !mapping.executable {
continue;
}
let mut start = mapping.start_address;
let mut end = start + mapping.size;
start >>= shift;
end >>= shift;
for bit in start..=end {
could_hit_mapping[(bit >> 3) & array_mask] |= 1 << (bit & 7);
}
}
let offset =
(sp_offset + std::mem::size_of::<usize>() - 1) & !(std::mem::size_of::<usize>() - 1);
for x in &mut stack_copy[0..offset] {
*x = 0;
}
let mut chunks = stack_copy[offset..].chunks_exact_mut(std::mem::size_of::<usize>());
for sp in &mut chunks {
let addr = usize::from_ne_bytes(sp.to_vec().as_slice().try_into()?);
let addr_signed = isize::from_ne_bytes(sp.to_vec().as_slice().try_into()?);
if addr <= small_int_magnitude as usize && addr_signed >= -small_int_magnitude {
continue;
}
if let Some(stack_map) = stack_mapping {
if stack_map.contains_address(addr) {
continue;
}
}
if let Some(last_hit) = last_hit_mapping {
if last_hit.contains_address(addr) {
continue;
}
}
let test = addr >> shift;
if could_hit_mapping[(test >> 3) & array_mask] & (1 << (test & 7)) != 0 {
if let Some(hit_mapping) = self.find_mapping_no_bias(addr) {
if hit_mapping.executable {
last_hit_mapping = Some(hit_mapping);
continue;
}
}
}
sp.copy_from_slice(&defaced);
}
for sp in chunks.into_remainder() {
*sp = 0;
}
Ok(())
}
pub fn find_mapping(&self, address: usize) -> Option<&MappingInfo> {
self.mappings
.iter()
.find(|map| address >= map.start_address && address - map.start_address < map.size)
}
pub fn find_mapping_no_bias(&self, address: usize) -> Option<&MappingInfo> {
self.mappings.iter().find(|map| {
address >= map.system_mapping_info.start_address
&& address < map.system_mapping_info.end_address
})
}
fn parse_build_id<'data>(
elf_obj: &elf::Elf<'data>,
mem_slice: &'data [u8],
) -> Option<&'data [u8]> {
if let Some(mut notes) = elf_obj.iter_note_headers(mem_slice) {
while let Some(Ok(note)) = notes.next() {
if note.n_type == elf::note::NT_GNU_BUILD_ID {
return Some(note.desc);
}
}
}
if let Some(mut notes) = elf_obj.iter_note_sections(mem_slice, Some(".note.gnu.build-id")) {
while let Some(Ok(note)) = notes.next() {
if note.n_type == elf::note::NT_GNU_BUILD_ID {
return Some(note.desc);
}
}
}
None
}
pub fn elf_file_identifier_from_mapped_file(mem_slice: &[u8]) -> Result<Vec<u8>, DumperError> {
let elf_obj = elf::Elf::parse(mem_slice)?;
if let Some(build_id) = Self::parse_build_id(&elf_obj, mem_slice) {
Ok(build_id.to_vec())
} else {
for section in elf_obj.section_headers {
if section.sh_type != elf::section_header::SHT_PROGBITS {
continue;
}
if section.sh_flags & u64::from(elf::section_header::SHF_ALLOC) != 0
&& section.sh_flags & u64::from(elf::section_header::SHF_EXECINSTR) != 0
{
let text_section =
&mem_slice[section.sh_offset as usize..][..section.sh_size as usize];
let max_len = std::cmp::min(text_section.len(), 4096);
let mut result = vec![0u8; std::mem::size_of::<GUID>()];
let mut offset = 0;
while offset < max_len {
for idx in 0..std::mem::size_of::<GUID>() {
if offset + idx >= text_section.len() {
break;
}
result[idx] ^= text_section[offset + idx];
}
offset += std::mem::size_of::<GUID>();
}
return Ok(result);
}
}
Err(DumperError::NoBuildIDFound)
}
}
pub fn elf_identifier_for_mapping_index(&mut self, idx: usize) -> Result<Vec<u8>, DumperError> {
assert!(idx < self.mappings.len());
Self::elf_identifier_for_mapping(&mut self.mappings[idx], self.pid)
}
pub fn elf_identifier_for_mapping(
mapping: &mut MappingInfo,
pid: Pid,
) -> Result<Vec<u8>, DumperError> {
if !MappingInfo::is_mapped_file_safe_to_open(&mapping.name) {
return Err(DumperError::NotSafeToOpenMapping(
mapping.name.clone().unwrap_or_default(),
));
}
if mapping.name.as_deref() == Some(LINUX_GATE_LIBRARY_NAME) {
if pid == std::process::id().try_into()? {
let mem_slice = unsafe {
std::slice::from_raw_parts(mapping.start_address as *const u8, mapping.size)
};
return Self::elf_file_identifier_from_mapped_file(mem_slice);
} else {
let mem_slice = Self::copy_from_process(
pid,
mapping.start_address as *mut libc::c_void,
mapping.size,
)?;
return Self::elf_file_identifier_from_mapped_file(&mem_slice);
}
}
let new_name = MappingInfo::handle_deleted_file_in_mapping(
mapping.name.as_deref().unwrap_or_default(),
pid,
)?;
let mem_slice = MappingInfo::get_mmap(&Some(new_name.clone()), mapping.offset)?;
let build_id = Self::elf_file_identifier_from_mapped_file(&mem_slice)?;
if let Some(old_name) = &mapping.name {
if &new_name != old_name {
mapping.name = Some(
old_name
.trim_end_matches(DELETED_SUFFIX)
.trim_end()
.to_string(),
);
}
}
Ok(build_id)
}
}