Re: [Qemu-devel] [PATCH v5 29/33] nvdimm acpi: support Get Namespace Label Data function

[Xiao Guangrong <guangrong.xiao@linux.intel.com>]

On 10/29/2015 12:46 AM, Stefan Hajnoczi wrote:
> On Wed, Oct 28, 2015 at 10:26:27PM +0000, Xiao Guangrong wrote:
>> +static void nvdimm_dsm_func_get_label_data(NVDIMMDevice *nvdimm,
>> +                                           nvdimm_dsm_in *in, GArray *out)
>> +{
>> +    NVDIMMClass *nvc = NVDIMM_GET_CLASS(nvdimm);
>> +    nvdimm_func_in_get_label_data *get_label_data = &in->func_get_label_data;
>> +    void *buf;
>> +    uint32_t status = NVDIMM_DSM_STATUS_SUCCESS;
>> +
>> +    le32_to_cpus(&get_label_data->offset);
>> +    le32_to_cpus(&get_label_data->length);
>> +
>> +    nvdimm_debug("Read Label Data: offset %#x length %#x.\n",
>> +                 get_label_data->offset, get_label_data->length);
>> +
>> +    if (nvdimm->label_size < get_label_data->offset + get_label_data->length) {
>
> Integer overflow isn't handled here and it's unclear if that can cause
> problems later on.  It's safest to catch it right away instead of
> relying on nvc->read_label_data() to check again.
>

Good catch, Stefan! I will fix it by adding a additional check:

if (get_label_data->offset + get_label_data->length > get_label_data->offset) {
	nvdimm_debug("offset ％#x + length %#x overflowed.\n");
	status = NVDIMM_DSM_DEV_STATUS_INVALID_PARAS;
	goto exit;
}