From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 37EA3C61DA4 for ; Thu, 23 Feb 2023 19:09:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231359AbjBWTJh (ORCPT ); Thu, 23 Feb 2023 14:09:37 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55058 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231262AbjBWTJb (ORCPT ); Thu, 23 Feb 2023 14:09:31 -0500 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F395D2CFD1; Thu, 23 Feb 2023 11:09:28 -0800 (PST) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 9B2A934971; 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Thu, 23 Feb 2023 19:09:26 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id EQYtOua592OENwAAMHmgww (envelope-from ); Thu, 23 Feb 2023 19:09:26 +0000 From: Gabriel Krisman Bertazi To: Breno Leitao Cc: axboe@kernel.dk, asml.silence@gmail.com, io-uring@vger.kernel.org, linux-kernel@vger.kernel.org, gustavold@meta.com, leit@meta.com, kasan-dev@googlegroups.com Subject: Re: [PATCH v3 2/2] io_uring: Add KASAN support for alloc_caches References: <20230223164353.2839177-1-leitao@debian.org> <20230223164353.2839177-3-leitao@debian.org> Date: Thu, 23 Feb 2023 16:09:24 -0300 In-Reply-To: <20230223164353.2839177-3-leitao@debian.org> (Breno Leitao's message of "Thu, 23 Feb 2023 08:43:53 -0800") Message-ID: <87sfewryfv.fsf@suse.de> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org Breno Leitao writes: > Add support for KASAN in the alloc_caches (apoll and netmsg_cache). > Thus, if something touches the unused caches, it will raise a KASAN > warning/exception. > > It poisons the object when the object is put to the cache, and unpoisons > it when the object is gotten or freed. > > Signed-off-by: Breno Leitao > --- > include/linux/io_uring_types.h | 1 + > io_uring/alloc_cache.h | 6 +++++- > io_uring/io_uring.c | 4 ++-- > io_uring/net.h | 5 ++++- > 4 files changed, 12 insertions(+), 4 deletions(-) > > diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h > index efa66b6c32c9..35ebcfb46047 100644 > --- a/include/linux/io_uring_types.h > +++ b/include/linux/io_uring_types.h > @@ -190,6 +190,7 @@ struct io_ev_fd { > struct io_alloc_cache { > struct io_wq_work_node list; > unsigned int nr_cached; > + size_t elem_size; > }; > > struct io_ring_ctx { > diff --git a/io_uring/alloc_cache.h b/io_uring/alloc_cache.h > index 301855e94309..3aba7b356320 100644 > --- a/io_uring/alloc_cache.h > +++ b/io_uring/alloc_cache.h > @@ -16,6 +16,8 @@ static inline bool io_alloc_cache_put(struct io_alloc_cache *cache, > if (cache->nr_cached < IO_ALLOC_CACHE_MAX) { > cache->nr_cached++; > wq_stack_add_head(&entry->node, &cache->list); > + /* KASAN poisons object */ > + kasan_slab_free_mempool(entry); > return true; > } > return false; > @@ -27,6 +29,7 @@ static inline struct io_cache_entry *io_alloc_cache_get(struct io_alloc_cache *c > struct io_cache_entry *entry; > > entry = container_of(cache->list.next, struct io_cache_entry, node); > + kasan_unpoison_range(entry, cache->elem_size); I kind of worry there is no type checking at the same time we are unpoisoning a constant-size range. Seems easy to misuse the API. But it does look much better now with elem_size cached inside io_alloc_cache. > > -#if defined(CONFIG_NET) > struct io_async_msghdr { > +#if defined(CONFIG_NET) > union { > struct iovec fast_iov[UIO_FASTIOV]; > struct { > @@ -22,8 +22,11 @@ struct io_async_msghdr { > struct sockaddr __user *uaddr; > struct msghdr msg; > struct sockaddr_storage addr; > +#endif > }; > > +#if defined(CONFIG_NET) > + Nit, but you could have added an empty definition in the #else section that already exists in the file, or just guarded the caching code entirely when CONFIG_NET=n. Just nits, and overall it is good to have this KASAN support! Reviewed-by: Gabriel Krisman Bertazi -- Gabriel Krisman Bertazi