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Wasmtime: Avoid a multiplication overflow when given 64-bit memories whose minimum size is the maximum memory64 size (#5533)

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This commit is contained in:
Nick Fitzgerald
2023-01-05 13:49:37 -08:00
committed by GitHub
parent 36e5bdfd0e
commit d5b8da6eea
1 changed files with 15 additions and 1 deletions
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16
crates/cranelift/src/func_environ.rs
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@@ -1381,6 +1381,20 @@ impl<'module_environment> cranelift_wasm::FuncEnvironment for FuncEnvironment<'m
fn make_heap(&mut self, func: &mut ir::Function, index: MemoryIndex) -> WasmResult<Heap> { fn make_heap(&mut self, func: &mut ir::Function, index: MemoryIndex) -> WasmResult<Heap> {
let pointer_type = self.pointer_type(); let pointer_type = self.pointer_type();
let is_shared = self.module.memory_plans[index].memory.shared; let is_shared = self.module.memory_plans[index].memory.shared;
let min_size = self.module.memory_plans[index]
.memory
.minimum
.checked_mul(u64::from(WASM_PAGE_SIZE))
.unwrap_or_else(|| {
// The only valid Wasm memory size that won't fit in a 64-bit
// integer is the maximum memory64 size (2^64) which is one
// larger than `u64::MAX` (2^64 - 1). In this case, just say the
// minimum heap size is `u64::MAX`.
debug_assert_eq!(self.module.memory_plans[index].memory.minimum, 1 << 48);
u64::MAX
});
let (ptr, base_offset, current_length_offset) = { let (ptr, base_offset, current_length_offset) = {
let vmctx = self.vmctx(func); let vmctx = self.vmctx(func);
if let Some(def_index) = self.module.defined_memory_index(index) { if let Some(def_index) = self.module.defined_memory_index(index) {
@@ -1471,7 +1485,7 @@ impl<'module_environment> cranelift_wasm::FuncEnvironment for FuncEnvironment<'m
}); });
Ok(self.heaps.push(HeapData { Ok(self.heaps.push(HeapData {
base: heap_base, base: heap_base,
min_size: self.module.memory_plans[index].memory.minimum * u64::from(WASM_PAGE_SIZE), min_size,
offset_guard_size, offset_guard_size,
style: heap_style, style: heap_style,
index_type: self.memory_index_type(index), index_type: self.memory_index_type(index),