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[81.154.179.160]) by smtp.gmail.com with ESMTPSA id n1-20020adfe781000000b002c54c9bd71fsm10192965wrm.93.2023.05.23.00.56.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 23 May 2023 00:56:39 -0700 (PDT) Date: Tue, 23 May 2023 08:56:38 +0100 From: Lorenzo Stoakes To: Vlastimil Babka Cc: Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, Kees Cook , linux-mm@kvack.org, linux-hardening@vger.kernel.org, patches@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/slab: remove HAVE_HARDENED_USERCOPY_ALLOCATOR Message-ID: References: <20230523073136.4900-1-vbabka@suse.cz> <310077ed-6f3f-41fe-afcf-36500a9408ec@lucifer.local> <623a87c6-c0d2-799a-c39e-0d14dcdfa6df@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <623a87c6-c0d2-799a-c39e-0d14dcdfa6df@suse.cz> X-Rspam-User: X-Stat-Signature: a886genkyseqtok197namks8wg9g1ouu X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: CB44FC0009 X-HE-Tag: 1684828601-749400 X-HE-Meta: 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 tm3k2zlK 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, May 23, 2023 at 09:46:46AM +0200, Vlastimil Babka wrote: > On 5/23/23 09:42, Lorenzo Stoakes wrote: > > On Tue, May 23, 2023 at 09:31:36AM +0200, Vlastimil Babka wrote: > >> With SLOB removed, both remaining allocators support hardened usercopy, > >> so remove the config and associated #ifdef. > >> > >> Signed-off-by: Vlastimil Babka > >> --- > >> mm/Kconfig | 2 -- > >> mm/slab.h | 9 --------- > >> security/Kconfig | 8 -------- > >> 3 files changed, 19 deletions(-) > >> > >> diff --git a/mm/Kconfig b/mm/Kconfig > >> index 7672a22647b4..041f0da42f2b 100644 > >> --- a/mm/Kconfig > >> +++ b/mm/Kconfig > >> @@ -221,7 +221,6 @@ choice > >> config SLAB > >> bool "SLAB" > >> depends on !PREEMPT_RT > >> - select HAVE_HARDENED_USERCOPY_ALLOCATOR > >> help > >> The regular slab allocator that is established and known to work > >> well in all environments. It organizes cache hot objects in > >> @@ -229,7 +228,6 @@ config SLAB > >> > >> config SLUB > >> bool "SLUB (Unqueued Allocator)" > >> - select HAVE_HARDENED_USERCOPY_ALLOCATOR > >> help > >> SLUB is a slab allocator that minimizes cache line usage > >> instead of managing queues of cached objects (SLAB approach). > >> diff --git a/mm/slab.h b/mm/slab.h > >> index f01ac256a8f5..695ef96b4b5b 100644 > >> --- a/mm/slab.h > >> +++ b/mm/slab.h > >> @@ -832,17 +832,8 @@ struct kmem_obj_info { > >> void __kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab); > >> #endif > >> > >> -#ifdef CONFIG_HAVE_HARDENED_USERCOPY_ALLOCATOR > >> void __check_heap_object(const void *ptr, unsigned long n, > >> const struct slab *slab, bool to_user); > >> -#else > >> -static inline > >> -void __check_heap_object(const void *ptr, unsigned long n, > >> - const struct slab *slab, bool to_user) > >> -{ > >> -} > >> -#endif > > > > Hm, this is still defined in slab.c/slub.c and invoked in usercopy.c, do we > > not want the prototype? > > Well I didn't delete the prototype, just the ifdef/else around, so now it's > there unconditionally. > > > Perhaps replacing with #ifdef > > CONFIG_HARDENED_USERCOPY instead? I may be missing something here :) > > Putting it under that #ifdef would work and match that the implementations > of that function are under that same ifdef, but maybe it's unnecessary noise > in the header? > Yeah my brain inserted extra '-'s there, sorry! Given we only define __check_heap_object() in sl[au]b.c if CONFIG_HARDENED_USERCOPY wouldn't we need to keep the empty version around if !CONFIG_HARDENED_USERCOPY since check_heap_object() appears to be called unconditionally?