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Fix access to VMMemoryDefinition::current_length on big-endian (#3013)

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The current_length member is defined as "usize" in Rust code,
but generated wasm code refers to it as if it were "u32".
While this happens to mostly work on little-endian machines
(as long as the length is < 4GB), it will always fail on
big-endian machines.

Fixed by making current_length "u32" in Rust as well, and
ensuring the actual memory size is always less than 4GB.
This commit is contained in:
Ulrich Weigand
2021-06-23 18:45:32 +02:00
committed by GitHub
parent b8c0ac72f1
commit 83007b79e3
7 changed files with 35 additions and 16 deletions
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8
crates/runtime/src/instance.rs
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@@ -703,10 +703,10 @@ impl Instance {
if src
.checked_add(len)
.map_or(true, |n| n as usize > src_mem.current_length)
.map_or(true, |n| n > src_mem.current_length)
|| dst
.checked_add(len)
.map_or(true, |m| m as usize > dst_mem.current_length)
.map_or(true, |m| m > dst_mem.current_length)
{
return Err(Trap::wasm(ir::TrapCode::HeapOutOfBounds));
}
@@ -741,7 +741,7 @@ impl Instance {
if dst
.checked_add(len)
.map_or(true, |m| m as usize > memory.current_length)
.map_or(true, |m| m > memory.current_length)
{
return Err(Trap::wasm(ir::TrapCode::HeapOutOfBounds));
}
@@ -825,7 +825,7 @@ impl Instance {
.map_or(true, |n| n as usize > data.len())
|| dst
.checked_add(len)
.map_or(true, |m| m as usize > memory.current_length)
.map_or(true, |m| m > memory.current_length)
{
return Err(Trap::wasm(ir::TrapCode::HeapOutOfBounds));
}