TensorFlow vulnerable to null-dereference in `mlir::tfg::TFOp::nameAttr`
### Impact
When `mlir::tfg::TFOp::nameAttr`
https://github.com/tensorflow/tensorflow/blob/master/tensorflow/core/ir/importexport/graphdef_import.cc receives null type list attributes, it crashes.
```cpp
StatusOr<unsigned> GraphDefImporter::ArgNumType(const NamedAttrList &attrs,
const OpDef::ArgDef &arg_def,
SmallVectorImpl<Type> &types) {
// Check whether a type list attribute is specified.
if (!arg_def.type_list_attr().empty()) {
if (auto v = attrs.get(arg_def.type_list_attr()).dyn_cast<ArrayAttr>()) {
for (Attribute attr : v) {
if (auto dtype = attr.dyn_cast<TypeAttr>()) {
types.push_back(UnrankedTensorType::get(dtype.getValue()));
} else {
return InvalidArgument("Expected '", arg_def.type_list_attr(),
"' to be a list of types");
}
}
return v.size();
}
return NotFound("Type attr not found: ", arg_def.type_list_attr());
}
unsigned num = 1;
// Check whether a number attribute is specified.
if (!arg_def.number_attr().empty()) {
if (auto v = attrs.get(arg_def.number_attr()).dyn_cast<IntegerAttr>()) {
num = v.getValue().getZExtValue();
} else {
return NotFound("Type attr not found: ", arg_def.number_attr());
}
}
// Check for a type or type attribute.
Type dtype;
if (arg_def.type() != DataType::DT_INVALID) {
TF_RETURN_IF_ERROR(ConvertDataType(arg_def.type(), b_, &dtype));
} else if (arg_def.type_attr().empty()) {
return InvalidArgument("Arg '", arg_def.name(),
"' has invalid type and no type attribute");
} else {
if (auto v = attrs.get(arg_def.type_attr()).dyn_cast<TypeAttr>()) {
dtype = v.getValue();
} else {
return NotFound("Type attr not found: ", arg_def.type_attr());
}
}
types.append(num, UnrankedTensorType::get(dtype));
return num;
}
```
### Patches
We have patched the issue in GitHub commits 3a754740d5414e362512ee981eefba41561a63a6
https://github.com/tensorflow/tensorflow/commit/3a754740d5414e362512ee981eefba41561a63a6 and a0f0b9a21c9270930457095092f558fbad4c03e5
https://github.com/tensorflow/tensorflow/commit/a0f0b9a21c9270930457095092f558fbad4c03e5.
The fix will be included in TensorFlow 2.10.0. We will also cherrypick this commit on TensorFlow 2.9.1, TensorFlow 2.8.1, and TensorFlow 2.7.2, as these are also affected and still in supported range.
### For more information
Please consult our security guide
https://github.com/tensorflow/tensorflow/blob/master/SECURITY.md for more information regarding the security model and how to contact us with issues and questions.