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Validate all memory data initializers before writing

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This commit is contained in:
Brandon Fish
2019-08-10 17:10:24 -06:00
parent 0c45b75e14
commit 0b73776c84
2 changed files with 61 additions and 35 deletions
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60
lib/runtime-core/src/backing.rs
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@ -130,6 +130,49 @@ impl LocalBacking {
memories: &mut SliceMap<LocalMemoryIndex, Memory>,
) -> LinkResult<BoxedMap<LocalMemoryIndex, *mut vm::LocalMemory>> {
// For each init that has some data...
// Validate data size fits
for init in module.info.data_initializers.iter() {
let init_base = match init.base {
Initializer::Const(Value::I32(offset)) => offset as u32,
Initializer::Const(_) => panic!("a const initializer must be the i32 type"),
Initializer::GetGlobal(import_global_index) => {
if let Value::I32(x) = imports.globals[import_global_index].get() {
x as u32
} else {
panic!("unsupported global type for initializer")
}
}
} as usize;
// Validate data size fits
match init.memory_index.local_or_import(&module.info) {
LocalOrImport::Local(local_memory_index) => {
let memory_desc = module.info.memories[local_memory_index];
let data_top = init_base + init.data.len();
if memory_desc.minimum.bytes().0 < data_top || data_top < init_base {
return Err(vec![LinkError::Generic {
message: "data segment does not fit".to_string(),
}]);
}
}
LocalOrImport::Import(imported_memory_index) => {
// Write the initialization data to the memory that
// we think the imported memory is.
unsafe {
let local_memory = &*imports.vm_memories[imported_memory_index];
let data_top = init_base + init.data.len();
if local_memory.bound < data_top || data_top < init_base {
return Err(vec![LinkError::Generic {
message: "data segment does not fit".to_string(),
}]);
}
}
}
}
}
// Initialize data
for init in module.info.data_initializers.iter() {
let init_base = match init.base {
Initializer::Const(Value::I32(offset)) => offset as u32,
@ -145,15 +188,6 @@ impl LocalBacking {
match init.memory_index.local_or_import(&module.info) {
LocalOrImport::Local(local_memory_index) => {
let memory_desc = module.info.memories[local_memory_index];
let data_top = init_base + init.data.len();
if memory_desc.minimum.bytes().0 < data_top || data_top < init_base {
return Err(vec![LinkError::Generic {
message: "data segment does not fit".to_string(),
}]);
}
let mem = &memories[local_memory_index];
for (mem_byte, data_byte) in mem.view()[init_base..init_base + init.data.len()]
.iter()
@ -167,14 +201,6 @@ impl LocalBacking {
// we think the imported memory is.
unsafe {
let local_memory = &*imports.vm_memories[imported_memory_index];
let data_top = init_base + init.data.len();
if local_memory.bound < data_top || data_top < init_base {
return Err(vec![LinkError::Generic {
message: "data segment does not fit".to_string(),
}]);
}
let memory_slice =
slice::from_raw_parts_mut(local_memory.base, local_memory.bound);