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fix: validate path components in sys_openat and handle empty paths #241

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fix: validate path components in sys_openat and handle empty paths #241

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19 changes: 19 additions & 0 deletions api/ruxos_posix_api/src/imp/fs.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -53,7 +53,12 @@ pub fn sys_open(filename: *const c_char, flags: c_int, mode: ctypes::mode_t) ->
/// Open a file under a specific dir
pub fn sys_openat(fd: c_int, path: *const c_char, flags: c_int, mode: ctypes::mode_t) -> c_int {
syscall_body!(sys_openat, {
let raw_path = char_ptr_to_path_str(path)?;
if raw_path.is_empty() {
return Err(LinuxError::ENOENT);
}
let path = parse_path_at(fd, path)?;
validate_path_components(&path)?;
let flags = OpenFlags::from_bits(flags).ok_or(LinuxError::EINVAL)?;
debug!("sys_openat <= fd {fd} {path:?}, {flags:?}, {mode:#o}");
let mode = FilePerm::from_bits_truncate(mode as u16 & !get_umask());
Expand Down Expand Up @@ -742,6 +747,20 @@ pub fn parse_path_at(dirfd: c_int, path: *const c_char) -> LinuxResult<AbsPath<'
}
}

const MAX_NAME_LEN: usize = 64;

fn validate_path_components(path: &AbsPath<'static>) -> LinuxResult {
for component in path.as_str().split('/') {
if component.is_empty() {
continue;
}
if component.len() > MAX_NAME_LEN {
return Err(LinuxError::ENAMETOOLONG);
}
}
Ok(())
}

fn file_from_fd(fd: i32) -> LinuxResult<Arc<File>> {
get_file_like(fd)?
.into_any()
Expand Down
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