bjoernager/rust
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detect bad vtables on an upcast

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This commit is contained in:
Ralf Jung 2022-07-20 11:36:19 -04:00
parent 0318f07bdd
commit 9927b3173b
1 changed files with 5 additions and 2 deletions
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7
compiler/rustc_const_eval/src/interpret/cast.rs
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@ -297,10 +297,13 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
Immediate::new_slice(ptr, length.eval_usize(*self.tcx, self.param_env), self);
self.write_immediate(val, dest)
}
(&ty::Dynamic(ref _data_a, ..), &ty::Dynamic(ref data_b, ..)) => {
(&ty::Dynamic(ref data_a, ..), &ty::Dynamic(ref data_b, ..)) => {
let (old_data, old_vptr) = self.read_immediate(src)?.to_scalar_pair()?;
let old_vptr = self.scalar_to_ptr(old_vptr)?;
let (ty, _) = self.get_ptr_vtable(old_vptr)?;
let (ty, old_trait) = self.get_ptr_vtable(old_vptr)?;
if old_trait != data_a.principal() {
throw_ub_format!("upcast on a pointer whose vtable does not match its type");
}
let new_vptr = self.get_vtable_ptr(ty, data_b.principal())?;
self.write_immediate(Immediate::new_dyn_trait(old_data, new_vptr, self), dest)
}