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CTFE validation: catch ReadPointerAsBytes and better error

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This commit is contained in:
Ralf Jung 2021-02-13 14:58:31 +01:00
parent dd4851d503
commit d6dcb3de54
2 changed files with 30 additions and 14 deletions
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42
compiler/rustc_mir/src/interpret/validity.rs
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@ -21,7 +21,7 @@ use std::hash::Hash;
use super::{
CheckInAllocMsg, GlobalAlloc, InterpCx, InterpResult, MPlaceTy, Machine, MemPlaceMeta, OpTy,
ValueVisitor,
ScalarMaybeUninit, ValueVisitor,
};
macro_rules! throw_validation_failure {
@ -378,7 +378,11 @@ impl<'rt, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> ValidityVisitor<'rt, 'mir, '
value: OpTy<'tcx, M::PointerTag>,
kind: &str,
) -> InterpResult<'tcx> {
let value = self.ecx.read_immediate(value)?;
let value = try_validation!(
self.ecx.read_immediate(value),
self.path,
err_unsup!(ReadPointerAsBytes) => { "part of a pointer" } expected { "a proper pointer or integer value" },
);
// Handle wide pointers.
// Check metadata early, for better diagnostics
let place = try_validation!(
@ -485,6 +489,17 @@ impl<'rt, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> ValidityVisitor<'rt, 'mir, '
Ok(())
}
fn read_scalar(
&self,
op: OpTy<'tcx, M::PointerTag>,
) -> InterpResult<'tcx, ScalarMaybeUninit<M::PointerTag>> {
Ok(try_validation!(
self.ecx.read_scalar(op),
self.path,
err_unsup!(ReadPointerAsBytes) => { "(potentially part of) a pointer" } expected { "plain (non-pointer) bytes" },
))
}
/// Check if this is a value of primitive type, and if yes check the validity of the value
/// at that type. Return `true` if the type is indeed primitive.
fn try_visit_primitive(
@ -495,7 +510,7 @@ impl<'rt, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> ValidityVisitor<'rt, 'mir, '
let ty = value.layout.ty;
match ty.kind() {
ty::Bool => {
let value = self.ecx.read_scalar(value)?;
let value = self.read_scalar(value)?;
try_validation!(
value.to_bool(),
self.path,
@ -505,7 +520,7 @@ impl<'rt, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> ValidityVisitor<'rt, 'mir, '
Ok(true)
}
ty::Char => {
let value = self.ecx.read_scalar(value)?;
let value = self.read_scalar(value)?;
try_validation!(
value.to_char(),
self.path,
@ -515,11 +530,7 @@ impl<'rt, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> ValidityVisitor<'rt, 'mir, '
Ok(true)
}
ty::Float(_) | ty::Int(_) | ty::Uint(_) => {
let value = try_validation!(
self.ecx.read_scalar(value),
self.path,
err_unsup!(ReadPointerAsBytes) => { "read of part of a pointer" },
);
let value = self.read_scalar(value)?;
// NOTE: Keep this in sync with the array optimization for int/float
// types below!
if self.ctfe_mode.is_some() {
@ -541,9 +552,10 @@ impl<'rt, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> ValidityVisitor<'rt, 'mir, '
// actually enforce the strict rules for raw pointers (mostly because
// that lets us re-use `ref_to_mplace`).
let place = try_validation!(
self.ecx.ref_to_mplace(self.ecx.read_immediate(value)?),
self.ecx.read_immediate(value).and_then(|i| self.ecx.ref_to_mplace(i)),
self.path,
err_ub!(InvalidUninitBytes(None)) => { "uninitialized raw pointer" },
err_unsup!(ReadPointerAsBytes) => { "part of a pointer" } expected { "a proper pointer or integer value" },
);
if place.layout.is_unsized() {
self.check_wide_ptr_meta(place.meta, place.layout)?;
@ -569,9 +581,13 @@ impl<'rt, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> ValidityVisitor<'rt, 'mir, '
Ok(true)
}
ty::FnPtr(_sig) => {
let value = self.ecx.read_scalar(value)?;
let value = try_validation!(
self.ecx.read_immediate(value),
self.path,
err_unsup!(ReadPointerAsBytes) => { "part of a pointer" } expected { "a proper pointer or integer value" },
);
let _fn = try_validation!(
value.check_init().and_then(|ptr| self.ecx.memory.get_fn(ptr)),
value.to_scalar().and_then(|ptr| self.ecx.memory.get_fn(ptr)),
self.path,
err_ub!(DanglingIntPointer(..)) |
err_ub!(InvalidFunctionPointer(..)) |
@ -615,7 +631,7 @@ impl<'rt, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> ValidityVisitor<'rt, 'mir, '
op: OpTy<'tcx, M::PointerTag>,
scalar_layout: &Scalar,
) -> InterpResult<'tcx> {
let value = self.ecx.read_scalar(op)?;
let value = self.read_scalar(op)?;
let valid_range = &scalar_layout.valid_range;
let (lo, hi) = valid_range.clone().into_inner();
// Determine the allowed range