Bug in Samba's implementation of FSCTL_QUERY_ALLOCATED_RANGES?

[David Howells]

Hi Jeremy,

> Bug is in fsctl_qar():
> 
>         ndr_ret = ndr_push_struct_blob(out_output, mem_ctx, &qar_rsp,
>                 (ndr_push_flags_fn_t)ndr_push_fsctl_query_alloced_ranges_rsp);
>         if (ndr_ret != NDR_ERR_SUCCESS) {
>                 DEBUG(0, ("failed to marshall QAR rsp\n"));
>                 return NT_STATUS_INVALID_PARAMETER;
>         }
> 
>         if (out_output->length > in_max_output) {
>                 DEBUG(2, ("QAR output len %lu exceeds max %lu\n",
>                           (unsigned long)out_output->length,
>                           (unsigned long)in_max_output));
>                 data_blob_free(out_output);
>                 return NT_STATUS_BUFFER_TOO_SMALL;
>         }
> 
> I'm guessing in this case we need to just truncate out_output->length
> to in_max_output and return STATUS_BUFFER_OVERFLOW.

Do you perchance have a fix for this?  I'm seeing it cause failures in
xfstests when running against cifs connected to samba.

Thanks,
David