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Add recursion limit to FFI safety lint

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Fixes stack overflow in the case of recursive types
This commit is contained in:
Gurinder Singh 2024-09-20 18:57:59 +05:30
parent e2dc1a1c0f
commit 716044751b
5 changed files with 50 additions and 18 deletions
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20
compiler/rustc_lint/src/types.rs
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@ -991,6 +991,8 @@ struct CTypesVisitorState<'tcx> {
/// The original type being checked, before we recursed
/// to any other types it contains.
base_ty: Ty<'tcx>,
/// Number of times we recursed while checking the type
recursion_depth: usize,
}
enum FfiResult<'tcx> {
@ -1296,12 +1298,23 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
// Protect against infinite recursion, for example
// `struct S(*mut S);`.
// FIXME: A recursion limit is necessary as well, for irregular
// recursive types.
if !acc.cache.insert(ty) {
return FfiSafe;
}
// Additional recursion check for more complex types like
// `struct A<T> { v: *const A<A<T>>, ... }` for which the
// cache check above won't be enough (fixes #130310)
if !tcx.recursion_limit().value_within_limit(acc.recursion_depth) {
return FfiUnsafe {
ty: acc.base_ty,
reason: fluent::lint_improper_ctypes_recursion_limit_reached,
help: None,
};
}
acc.recursion_depth += 1;
match *ty.kind() {
ty::Adt(def, args) => {
if let Some(boxed) = ty.boxed_ty()
@ -1644,7 +1657,8 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
return;
}
let mut acc = CTypesVisitorState { cache: FxHashSet::default(), base_ty: ty };
let mut acc =
CTypesVisitorState { cache: FxHashSet::default(), base_ty: ty, recursion_depth: 0 };
match self.check_type_for_ffi(&mut acc, ty) {
FfiResult::FfiSafe => {}
FfiResult::FfiPhantom(ty) => {