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fix validate_atomic_addr() #5063

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fix validate_atomic_addr() #5063

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36 changes: 18 additions & 18 deletions crates/runtime/src/libcalls.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -437,14 +437,9 @@ unsafe fn memory_atomic_notify(
addr: *mut u8,
_count: u32,
) -> Result<u32, TrapReason> {
let addr = addr as usize;
let memory = MemoryIndex::from_u32(memory_index);
let instance = (*vmctx).instance();
// this should never overflow since addr + 4 either hits a guard page
// or it's been validated to be in-bounds already. Double-check for now
// just to be sure.
let addr_to_check = addr.checked_add(4).unwrap();
validate_atomic_addr(instance, memory, addr_to_check)?;
validate_atomic_addr(instance, memory, addr, 4)?;
Err(
anyhow::anyhow!("unimplemented: wasm atomics (fn memory_atomic_notify) unsupported",)
.into(),
Expand All @@ -459,13 +454,9 @@ unsafe fn memory_atomic_wait32(
_expected: u32,
_timeout: u64,
) -> Result<u32, TrapReason> {
let addr = addr as usize;
let memory = MemoryIndex::from_u32(memory_index);
let instance = (*vmctx).instance();
// see wasmtime_memory_atomic_notify for why this shouldn't overflow
// but we still double-check
let addr_to_check = addr.checked_add(4).unwrap();
validate_atomic_addr(instance, memory, addr_to_check)?;
validate_atomic_addr(instance, memory, addr, 4)?;
Err(
anyhow::anyhow!("unimplemented: wasm atomics (fn memory_atomic_wait32) unsupported",)
.into(),
Expand All @@ -480,13 +471,9 @@ unsafe fn memory_atomic_wait64(
_expected: u64,
_timeout: u64,
) -> Result<u32, TrapReason> {
let addr = addr as usize;
let memory = MemoryIndex::from_u32(memory_index);
let instance = (*vmctx).instance();
// see wasmtime_memory_atomic_notify for why this shouldn't overflow
// but we still double-check
let addr_to_check = addr.checked_add(8).unwrap();
validate_atomic_addr(instance, memory, addr_to_check)?;
validate_atomic_addr(instance, memory, addr, 8)?;
Err(
anyhow::anyhow!("unimplemented: wasm atomics (fn memory_atomic_wait64) unsupported",)
.into(),
Expand All @@ -505,9 +492,22 @@ unsafe fn memory_atomic_wait64(
unsafe fn validate_atomic_addr(
instance: &Instance,
memory: MemoryIndex,
addr: usize,
addr: *const u8,
size: usize,
) -> Result<(), TrapCode> {
if addr > instance.get_memory(memory).current_length() {
let mem = instance.get_memory(memory);

let end_addr = (addr as usize).checked_add(size).unwrap();

if addr < mem.base {
return Err(TrapCode::HeapOutOfBounds);
}

if end_addr
>= (mem.base as usize)
.checked_add(mem.current_length())
.unwrap()
{
return Err(TrapCode::HeapOutOfBounds);
}
Ok(())
Expand Down