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also use compute_size_in_bytes for relevant multiplications in Miri

This commit is contained in:
Ralf Jung 2024-09-14 10:28:17 +02:00
parent 3b806d337c
commit 268f6cf558
8 changed files with 64 additions and 40 deletions
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11
compiler/rustc_const_eval/src/interpret/intrinsics.rs
View File

@ -216,7 +216,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
self.copy_intrinsic(&args[0], &args[1], &args[2], /*nonoverlapping*/ false)?;
}
sym::write_bytes => {
self.write_bytes_intrinsic(&args[0], &args[1], &args[2])?;
self.write_bytes_intrinsic(&args[0], &args[1], &args[2], "write_bytes")?;
}
sym::compare_bytes => {
let result = self.compare_bytes_intrinsic(&args[0], &args[1], &args[2])?;
@ -634,11 +634,12 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
Ok(())
}
pub(crate) fn write_bytes_intrinsic(
pub fn write_bytes_intrinsic(
&mut self,
dst: &OpTy<'tcx, <M as Machine<'tcx>>::Provenance>,
byte: &OpTy<'tcx, <M as Machine<'tcx>>::Provenance>,
count: &OpTy<'tcx, <M as Machine<'tcx>>::Provenance>,
name: &'static str,
) -> InterpResult<'tcx> {
let layout = self.layout_of(dst.layout.ty.builtin_deref(true).unwrap())?;
@ -648,9 +649,9 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
// `checked_mul` enforces a too small bound (the correct one would probably be target_isize_max),
// but no actual allocation can be big enough for the difference to be noticeable.
let len = self.compute_size_in_bytes(layout.size, count).ok_or_else(|| {
err_ub_custom!(fluent::const_eval_size_overflow, name = "write_bytes")
})?;
let len = self
.compute_size_in_bytes(layout.size, count)
.ok_or_else(|| err_ub_custom!(fluent::const_eval_size_overflow, name = name))?;
let bytes = std::iter::repeat(byte).take(len.bytes_usize());
self.write_bytes_ptr(dst, bytes)

7
compiler/rustc_const_eval/src/interpret/memory.rs
View File

@ -222,7 +222,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
} else {
Allocation::try_uninit(size, align)?
};
self.allocate_raw_ptr(alloc, kind)
self.insert_allocation(alloc, kind)
}
pub fn allocate_bytes_ptr(
@ -233,14 +233,15 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
mutability: Mutability,
) -> InterpResult<'tcx, Pointer<M::Provenance>> {
let alloc = Allocation::from_bytes(bytes, align, mutability);
self.allocate_raw_ptr(alloc, kind)
self.insert_allocation(alloc, kind)
}
pub fn allocate_raw_ptr(
pub fn insert_allocation(
&mut self,
alloc: Allocation<M::Provenance, (), M::Bytes>,
kind: MemoryKind<M::MemoryKind>,
) -> InterpResult<'tcx, Pointer<M::Provenance>> {
assert!(alloc.size() <= self.max_size_of_val());
let id = self.tcx.reserve_alloc_id();
debug_assert_ne!(
Some(kind),

2
compiler/rustc_const_eval/src/interpret/operator.rs
View File

@ -290,7 +290,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
/// Computes the total size of this access, `count * elem_size`,
/// checking for overflow beyond isize::MAX.
pub(super) fn compute_size_in_bytes(&self, elem_size: Size, count: u64) -> Option<Size> {
pub fn compute_size_in_bytes(&self, elem_size: Size, count: u64) -> Option<Size> {
// `checked_mul` applies `u64` limits independent of the target pointer size... but the
// subsequent check for `max_size_of_val` means we also handle 32bit targets correctly.
// (We cannot use `Size::checked_mul` as that enforces `obj_size_bound` as the limit, which

2
src/tools/miri/src/concurrency/thread.rs
View File

@ -898,7 +898,7 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
// This allocation will be deallocated when the thread dies, so it is not in read-only memory.
alloc.mutability = Mutability::Mut;
// Create a fresh allocation with this content.
let ptr = this.allocate_raw_ptr(alloc, MiriMemoryKind::Tls.into())?;
let ptr = this.insert_allocation(alloc, MiriMemoryKind::Tls.into())?;
this.machine.threads.set_thread_local_alloc(def_id, ptr);
Ok(ptr)
}

17
src/tools/miri/src/intrinsics/mod.rs
View File

@ -3,11 +3,8 @@
mod atomic;
mod simd;
use std::iter;
use rand::Rng;
use rustc_apfloat::{Float, Round};
use rustc_middle::ty::layout::LayoutOf;
use rustc_middle::{
mir,
ty::{self, FloatTy},
@ -119,19 +116,9 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
this.copy_op(dest, &place)?;
}
"write_bytes" | "volatile_set_memory" => {
"volatile_set_memory" => {
let [ptr, val_byte, count] = check_arg_count(args)?;
let ty = ptr.layout.ty.builtin_deref(true).unwrap();
let ty_layout = this.layout_of(ty)?;
let val_byte = this.read_scalar(val_byte)?.to_u8()?;
let ptr = this.read_pointer(ptr)?;
let count = this.read_target_usize(count)?;
// `checked_mul` enforces a too small bound (the correct one would probably be target_isize_max),
// but no actual allocation can be big enough for the difference to be noticeable.
let byte_count = ty_layout.size.checked_mul(count, this).ok_or_else(|| {
err_ub_format!("overflow computing total size of `{intrinsic_name}`")
})?;
this.write_bytes_ptr(ptr, iter::repeat(val_byte).take(byte_count.bytes_usize()))?;
this.write_bytes_intrinsic(ptr, val_byte, count, "volatile_set_memory")?;
}
// Memory model / provenance manipulation

48
src/tools/miri/src/shims/foreign_items.rs
View File

@ -196,7 +196,7 @@ trait EvalContextExtPriv<'tcx>: crate::MiriInterpCxExt<'tcx> {
if size == 0 {
throw_ub_format!("creating allocation with size 0");
}
if i128::from(size) > this.tcx.data_layout.pointer_size.signed_int_max() {
if size > this.max_size_of_val().bytes() {
throw_ub_format!("creating an allocation larger than half the address space");
}
if let Err(e) = Align::from_bytes(align) {
@ -441,19 +441,34 @@ trait EvalContextExtPriv<'tcx>: crate::MiriInterpCxExt<'tcx> {
"malloc" => {
let [size] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
let size = this.read_target_usize(size)?;
let res = this.malloc(size, /*zero_init:*/ false)?;
this.write_pointer(res, dest)?;
if size <= this.max_size_of_val().bytes() {
let res = this.malloc(size, /*zero_init:*/ false)?;
this.write_pointer(res, dest)?;
} else {
// If this does not fit in an isize, return null and, on Unix, set errno.
if this.target_os_is_unix() {
let einval = this.eval_libc("ENOMEM");
this.set_last_error(einval)?;
}
this.write_null(dest)?;
}
}
"calloc" => {
let [items, len] =
let [items, elem_size] =
this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
let items = this.read_target_usize(items)?;
let len = this.read_target_usize(len)?;
let size = items
.checked_mul(len)
.ok_or_else(|| err_ub_format!("overflow during calloc size computation"))?;
let res = this.malloc(size, /*zero_init:*/ true)?;
this.write_pointer(res, dest)?;
let elem_size = this.read_target_usize(elem_size)?;
if let Some(size) = this.compute_size_in_bytes(Size::from_bytes(elem_size), items) {
let res = this.malloc(size.bytes(), /*zero_init:*/ true)?;
this.write_pointer(res, dest)?;
} else {
// On size overflow, return null and, on Unix, set errno.
if this.target_os_is_unix() {
let einval = this.eval_libc("ENOMEM");
this.set_last_error(einval)?;
}
this.write_null(dest)?;
}
}
"free" => {
let [ptr] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
@ -465,8 +480,17 @@ trait EvalContextExtPriv<'tcx>: crate::MiriInterpCxExt<'tcx> {
this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
let old_ptr = this.read_pointer(old_ptr)?;
let new_size = this.read_target_usize(new_size)?;
let res = this.realloc(old_ptr, new_size)?;
this.write_pointer(res, dest)?;
if new_size <= this.max_size_of_val().bytes() {
let res = this.realloc(old_ptr, new_size)?;
this.write_pointer(res, dest)?;
} else {
// If this does not fit in an isize, return null and, on Unix, set errno.
if this.target_os_is_unix() {
let einval = this.eval_libc("ENOMEM");
this.set_last_error(einval)?;
}
this.write_null(dest)?;
}
}
// Rust allocation

4
src/tools/miri/src/shims/unix/foreign_items.rs
View File

@ -363,14 +363,14 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
//
// Linux: https://www.unix.com/man-page/linux/3/reallocarray/
// FreeBSD: https://man.freebsd.org/cgi/man.cgi?query=reallocarray
match nmemb.checked_mul(size) {
match this.compute_size_in_bytes(Size::from_bytes(size), nmemb) {
None => {
let einval = this.eval_libc("ENOMEM");
this.set_last_error(einval)?;
this.write_null(dest)?;
}
Some(len) => {
let res = this.realloc(ptr, len)?;
let res = this.realloc(ptr, len.bytes())?;
this.write_pointer(res, dest)?;
}
}

13
src/tools/miri/tests/pass-dep/libc/libc-mem.rs
View File

@ -101,6 +101,10 @@ fn test_malloc() {
let slice = slice::from_raw_parts(p3 as *const u8, 20);
assert_eq!(&slice, &[0_u8; 20]);
// new size way too big (so this doesn't actually realloc).
let p_too_big = libc::realloc(p3, usize::MAX);
assert!(p_too_big.is_null());
// old size > new size
let p4 = libc::realloc(p3, 10);
let slice = slice::from_raw_parts(p4 as *const u8, 10);
@ -119,9 +123,13 @@ fn test_malloc() {
unsafe {
let p1 = libc::realloc(ptr::null_mut(), 20);
assert!(!p1.is_null());
libc::free(p1);
}
unsafe {
let p_too_big = libc::malloc(usize::MAX);
assert!(p_too_big.is_null());
}
}
fn test_calloc() {
@ -143,6 +151,9 @@ fn test_calloc() {
let slice = slice::from_raw_parts(p4 as *const u8, 4 * 8);
assert_eq!(&slice, &[0_u8; 4 * 8]);
libc::free(p4);
let p_too_big = libc::calloc(usize::MAX / 4, 4);
assert!(p_too_big.is_null());
}
}