On Thu, 12 Jan 2012, Pekka Enberg wrote: > I think you missed Andrew's point. We absolutely want to issue a > kernel warning here because ecryptfs is misusing the memdup_user() > API. We must not let userspace processes allocate large amounts of > memory arbitrarily. > I think it's good to fix ecryptfs like Tyler is doing and, at the same time, ensure that the len passed to memdup_user() makes sense prior to kmallocing memory with GFP_KERNEL. Perhaps something like if (WARN_ON(len > PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER)) return ERR_PTR(-ENOMEM); in which case __GFP_NOWARN is irrelevant. I think memdup_user() should definitely be taking gfp flags, though, so the caller can specify things like __GFP_NORETRY on its own to avoid infinitely looping in the page allocator trying reclaim and possibly calling the oom killer. -- To unsubscribe from this list: send the line "unsubscribe ecryptfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
