On Thu, Aug 03, 2023 at 03:07:23AM +0000, Liu, Yi L wrote:
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.
And here too with a WARN_ON_ONCE.
/** Either the driver is broken by having an invalid size, or the user* invalidate data struct used by the driver is missing in the union.*/if (WARN_ON_ONCE(hwpt->domain->ops->cache_invalidate_user &&(!hwpt->domain->ops->cache_invalidate_user_data_len ||hwpt->domain->ops->cache_invalidate_user_data_len >sizeof(union ucmd_buffer)))) {rc = -EINVAL;goto out_abort;}Though I am making this cache_invalidate_user optional here, I wonder if there actually could be a case that a user-managed domain doesn't need a cache_invalidate_user op...
If user-managed domain is the stage-1 domain in nested, then seems not possible as cache invalidate is a must. But I think this logic is fine as not all the domains allocated by the user is user-managed. It may be kernel managed like the s2 domains.
Oh, I forgot to mention that this piece is in the user-managed HWPT allocator, following Jason's suggestion to separate them.
So, perhaps should just mark it mandatory:
+ if (WARN_ON_ONCE(!hwpt->domain->ops->cache_invalidate_user || + !hwpt->domain->ops->cache_invalidate_user_data_len || + hwpt->domain->ops->cache_invalidate_user_data_len > + sizeof(union iommu_user_cache_invalidate))) { + rc = -EINVAL; + goto out_abort; + }