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Optionally deny floating point operations (#83) 

* Optionally deny floating point operations

* Deny floating-point parameters and fix docs/indentation

* Test denial of floating-point parameters
This commit is contained in:
Jef 2018-04-18 14:09:09 +02:00 committed by Sergey Pepyakin
parent a2aa3ddb25
commit 22b260a3b9
2 changed files with 173 additions and 1 deletions
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61
src/lib.rs
View File

@ -385,7 +385,6 @@ pub struct Module {
}
impl Module {
/// Create `Module` from `parity_wasm::elements::Module`.
///
/// This function will load, validate and prepare a `parity_wasm`'s `Module`.
@ -431,6 +430,66 @@ impl Module {
})
}
/// Fail if the module contains any floating-point operations
///
/// # Errors
///
/// Returns `Err` if provided `Module` is not valid.
///
/// # Examples
///
/// ```rust
/// # extern crate wasmi;
/// # extern crate wabt;
///
/// let wasm_binary: Vec<u8> =
/// wabt::wat2wasm(
/// r#"
/// (module
/// (func $add (param $lhs i32) (param $rhs i32) (result i32)
/// get_local $lhs
/// get_local $rhs
/// i32.add))
/// "#,
/// )
/// .expect("failed to parse wat");
///
/// // Load wasm binary and prepare it for instantiation.
/// let module = wasmi::Module::from_buffer(&wasm_binary).expect("Parsing failed");
/// assert!(module.deny_floating_point().is_ok());
///
/// let wasm_binary: Vec<u8> =
/// wabt::wat2wasm(
/// r#"
/// (module
/// (func $add (param $lhs f32) (param $rhs f32) (result f32)
/// get_local $lhs
/// get_local $rhs
/// f32.add))
/// "#,
/// )
/// .expect("failed to parse wat");
///
/// let module = wasmi::Module::from_buffer(&wasm_binary).expect("Parsing failed");
/// assert!(module.deny_floating_point().is_err());
///
/// let wasm_binary: Vec<u8> =
/// wabt::wat2wasm(
/// r#"
/// (module
/// (func $add (param $lhs f32) (param $rhs f32) (result f32)
/// get_local $lhs))
/// "#,
/// )
/// .expect("failed to parse wat");
///
/// let module = wasmi::Module::from_buffer(&wasm_binary).expect("Parsing failed");
/// assert!(module.deny_floating_point().is_err());
/// ```
pub fn deny_floating_point(&self) -> Result<(), Error> {
validation::deny_floating_point(&self.module).map_err(Into::into)
}
/// Create `Module` from a given buffer.
///
/// This function will deserialize wasm module from a given module,

113
src/validation/mod.rs
View File

@ -50,6 +50,119 @@ impl ::std::ops::Deref for ValidatedModule {
}
}
pub fn deny_floating_point(module: &Module) -> Result<(), Error> {
if let Some(code) = module.code_section() {
for op in code.bodies().iter().flat_map(|body| body.code().elements()) {
use parity_wasm::elements::Opcode::*;
macro_rules! match_eq {
($pattern:pat) => {
|val| if let $pattern = *val { true } else { false }
};
}
const DENIED: &[fn(&Opcode) -> bool] = &[
match_eq!(F32Load(_, _)),
match_eq!(F64Load(_, _)),
match_eq!(F32Store(_, _)),
match_eq!(F64Store(_, _)),
match_eq!(F32Const(_)),
match_eq!(F64Const(_)),
match_eq!(F32Eq),
match_eq!(F32Ne),
match_eq!(F32Lt),
match_eq!(F32Gt),
match_eq!(F32Le),
match_eq!(F32Ge),
match_eq!(F64Eq),
match_eq!(F64Ne),
match_eq!(F64Lt),
match_eq!(F64Gt),
match_eq!(F64Le),
match_eq!(F64Ge),
match_eq!(F32Abs),
match_eq!(F32Neg),
match_eq!(F32Ceil),
match_eq!(F32Floor),
match_eq!(F32Trunc),
match_eq!(F32Nearest),
match_eq!(F32Sqrt),
match_eq!(F32Add),
match_eq!(F32Sub),
match_eq!(F32Mul),
match_eq!(F32Div),
match_eq!(F32Min),
match_eq!(F32Max),
match_eq!(F32Copysign),
match_eq!(F64Abs),
match_eq!(F64Neg),
match_eq!(F64Ceil),
match_eq!(F64Floor),
match_eq!(F64Trunc),
match_eq!(F64Nearest),
match_eq!(F64Sqrt),
match_eq!(F64Add),
match_eq!(F64Sub),
match_eq!(F64Mul),
match_eq!(F64Div),
match_eq!(F64Min),
match_eq!(F64Max),
match_eq!(F64Copysign),
match_eq!(F32ConvertSI32),
match_eq!(F32ConvertUI32),
match_eq!(F32ConvertSI64),
match_eq!(F32ConvertUI64),
match_eq!(F32DemoteF64),
match_eq!(F64ConvertSI32),
match_eq!(F64ConvertUI32),
match_eq!(F64ConvertSI64),
match_eq!(F64ConvertUI64),
match_eq!(F64PromoteF32),
match_eq!(F32ReinterpretI32),
match_eq!(F64ReinterpretI64),
match_eq!(I32TruncSF32),
match_eq!(I32TruncUF32),
match_eq!(I32TruncSF64),
match_eq!(I32TruncUF64),
match_eq!(I64TruncSF32),
match_eq!(I64TruncUF32),
match_eq!(I64TruncSF64),
match_eq!(I64TruncUF64),
match_eq!(I32ReinterpretF32),
match_eq!(I64ReinterpretF64),
];
if DENIED.iter().any(|is_denied| is_denied(op)) {
return Err(Error(format!("Floating point operation denied: {:?}", op)));
}
}
}
if let (Some(sec), Some(types)) = (module.function_section(), module.type_section()) {
use parity_wasm::elements::{Type, ValueType};
let types = types.types();
for sig in sec.entries() {
if let Some(typ) = types.get(sig.type_ref() as usize) {
match *typ {
Type::Function(ref func) => {
if func.params()
.iter()
.chain(func.return_type().as_ref())
.any(|&typ| typ == ValueType::F32 || typ == ValueType::F64)
{
return Err(Error(format!("Use of floating point types denied")));
}
}
}
}
}
}
Ok(())
}
pub fn validate_module(module: Module) -> Result<ValidatedModule, Error> {
let mut context_builder = ModuleContextBuilder::new();
let mut imported_globals = Vec::new();