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Fix more fuzz found panics #499

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merged 2 commits into from
Mar 24, 2024
Merged

Fix more fuzz found panics #499

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b05debe
Fix more fuzz found panics
wcampbell0x2a Mar 1, 2024
c4b0a89
unsquashfs: Improve error for invalid image
wcampbell0x2a Mar 3, 2024
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9 changes: 8 additions & 1 deletion backhand-cli/src/bin/unsquashfs.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -205,7 +205,14 @@ fn main() -> ExitCode {
return ExitCode::SUCCESS;
}

let squashfs = Squashfs::from_reader_with_offset_and_kind(file, args.offset, kind).unwrap();
let squashfs = match Squashfs::from_reader_with_offset_and_kind(file, args.offset, kind) {
Ok(s) => s,
Err(_e) => {
let line = format!("{:>14}", red_bold.apply_to(format!("Could not read image: {_e}")));
pb.finish_with_message(line);
return ExitCode::FAILURE;
}
};
let root_process = unsafe { geteuid() == 0 };
if root_process {
umask(Mode::from_bits(0).unwrap());
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24 changes: 17 additions & 7 deletions backhand/src/squashfs.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -464,10 +464,16 @@ impl<'b> Squashfs<'b> {
return Ok(None);
}

// ignore blocks before our block_index, grab all the rest of the bytes
// TODO: perf
let offset = self.dir_blocks.0.get(&block_index).unwrap();
let block = &self.dir_blocks.1[*offset as usize..];
let Some(offset) = self.dir_blocks.0.get(&block_index) else {
return Err(BackhandError::CorruptedOrInvalidSquashfs);
};
let Some(block) = &self.dir_blocks.1.get(*offset as usize..) else {
return Err(BackhandError::CorruptedOrInvalidSquashfs);
};

if (block.len() as u32) < (block_offset as u32 + file_size - 3) {
return Err(BackhandError::CorruptedOrInvalidSquashfs);
}

let bytes = &block[block_offset..][..file_size as usize - 3];
let mut dirs = vec![];
Expand Down Expand Up @@ -512,9 +518,13 @@ impl<'b> Squashfs<'b> {
for d in &dirs {
trace!("extracting entry: {:#?}", d.dir_entries);
for entry in &d.dir_entries {
let inode_key =
(d.inode_num as i32 + entry.inode_offset as i32).try_into().unwrap();
let found_inode = &self.inodes[&inode_key];
let Ok(inode_key) = (d.inode_num as i32 + entry.inode_offset as i32).try_into()
else {
return Err(BackhandError::CorruptedOrInvalidSquashfs);
};
let Some(found_inode) = &self.inodes.get(&inode_key) else {
return Err(BackhandError::CorruptedOrInvalidSquashfs);
};
let header = found_inode.header;
fullpath.push(entry.name()?);

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