On Mon, Jul 31, 2023 at 10:07:32AM +0000, Liu, Yi L wrote: > > > + goto out_put_hwpt; > > > + } > > > + > > > + /* > > > + * Copy the needed fields before reusing the ucmd buffer, this > > > + * avoids memory allocation in this path. > > > + */ > > > + user_ptr = cmd->data_uptr; > > > + user_data_len = cmd->data_len; > > > > Uhh, who checks that klen < the temporary stack struct? > > Take vtd as an example. The invalidate structure is struct iommu_hwpt_vtd_s1_invalidate[1]. > The klen is sizeof(struct iommu_hwpt_vtd_s1_invalidate)[2]. iommu_hwpt_vtd_s1_invalidate > is also placed in the temporary stack struct (actually it is a union)[1]. So the klen should > be <= temporary stack. Ohh, I think I would add a few comments noting that the invalidate structs need to be added to that union. Easy to miss. > It's not so explicit though. Perhaps worth to have a check like below in this patch? > > if (unlikely(klen > sizeof(union ucmd_buffer))) > return -EINVAL; Yes, stick this in the domain allocate path with a WARN_ON. The driver is broken to allocate a domain with an invalid size. Jason
