Struct Limits 

#[non_exhaustive]
pub struct Limits {
    pub max_sections: u32,
    pub max_symbols: u32,
    pub max_relocations: u64,
    pub max_name_len: u32,
    pub max_name_bytes: u64,
}

Budgets for reading untrusted files.

Every reader checks its input against these before allocating for it. Section data, symbol records, and relocation records are also bounded by the input itself (a reader copies at most as many bytes of section data as the file holds, however its headers overlap), so the budgets that matter most are the ones on names: a hostile file can point many symbols at one long string, and only max_name_bytes stops that from multiplying.

The defaults sit far above what compilers produce and far below what would exhaust a machine. The struct is #[non_exhaustive]: start from Limits::default and change fields.

Field	Default	Bounds
max_sections	1,048,576	section headers
max_symbols	16,777,216	symbol table entries
max_relocations	67,108,864	relocation records, all sections together
max_name_len	65,536 bytes	one section or symbol name
max_name_bytes	268,435,456 bytes (256 MiB)	all names together, as copied out

Examples

use object_lang::{Architecture, Limits, Object, ReadError, Section, SectionKind};

let mut obj = Object::relocatable(Architecture::X86_64);
obj.add_section(Section::new(".text", SectionKind::Text));
obj.add_section(Section::new(".data", SectionKind::Data));
let bytes = object_lang::elf::write(&obj)?;

let mut limits = Limits::default();
limits.max_sections = 3;
assert_eq!(
    object_lang::elf::read_with_limits(&bytes, &limits),
    Err(ReadError::LimitExceeded { limit: "max_sections" }),
);

Fields (Non-exhaustive)

Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.

max_sections: u32

The most section headers a file may have.

max_symbols: u32

The most entries a symbol table may have.

max_relocations: u64

The most relocation records, over all sections.

max_name_len: u32

The longest a single name may be, in bytes.

max_name_bytes: u64

The most name bytes copied out of the file, over all names.

Implementations

impl Limits

pub const DEFAULT: Limits

The default budgets, as a constant.

Examples

use object_lang::Limits;

assert_eq!(Limits::DEFAULT, Limits::default());

Trait Implementations

impl Clone for Limits

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for Limits

impl Debug for Limits

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for Limits

fn default() -> Self

Returns the “default value” for a type.

impl Eq for Limits

impl Hash for Limits

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for Limits

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for Limits