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Wed, 25 Aug 2021 14:31:46 -0700 (PDT) MIME-Version: 1.0 References: <20210818214021.2476230-1-keescook@chromium.org> <20210818214021.2476230-5-keescook@chromium.org> In-Reply-To: <20210818214021.2476230-5-keescook@chromium.org> From: Nick Desaulniers Date: Wed, 25 Aug 2021 14:31:34 -0700 Message-ID: Subject: Re: [PATCH v2 4/7] slab: Add __alloc_size attributes for better bounds checking To: Kees Cook Cc: linux-kernel@vger.kernel.org, Daniel Micay , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Vlastimil Babka , linux-mm@kvack.org, Joe Perches , Miguel Ojeda , Nathan Chancellor , Andy Whitcroft , Dwaipayan Ray , Lukas Bulwahn , Dennis Zhou , Tejun Heo , Masahiro Yamada , Michal Marek , clang-built-linux@googlegroups.com, linux-kbuild@vger.kernel.org, linux-hardening@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=google.com header.s=20161025 header.b=M9bx0SOn; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf30.hostedemail.com: domain of ndesaulniers@google.com designates 209.85.167.50 as permitted sender) smtp.mailfrom=ndesaulniers@google.com X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 180FCE00199A X-Stat-Signature: 6tym7kayzp4bs8sxpsus6gbjgf6pchnu X-HE-Tag: 1629927107-580860 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 Wed, Aug 18, 2021 at 2:40 PM Kees Cook wrote: > > As already done in GrapheneOS, add the __alloc_size attribute for > regular kmalloc interfaces, to provide additional hinting for better > bounds checking, assisting CONFIG_FORTIFY_SOURCE and other compiler > optimizations. > > Co-developed-by: Daniel Micay > Signed-off-by: Daniel Micay > Cc: Christoph Lameter > Cc: Pekka Enberg > Cc: David Rientjes > Cc: Joonsoo Kim > Cc: Andrew Morton > Cc: Vlastimil Babka > Cc: linux-mm@kvack.org > Signed-off-by: Kees Cook This is a good start, so Reviewed-by: Nick Desaulniers Do we also want to attribute: * __kmalloc_index * kmem_cache_free_bulk * kmem_cache_alloc_bulk * kmem_cache_alloc_trace * kmalloc_order * kmalloc_order_trace * kmalloc_large * kmalloc_node * __kmalloc_track_caller * kmalloc_array_node * __kmalloc_node_track_caller > --- > include/linux/slab.h | 20 ++++++++++++++++++-- > 1 file changed, 18 insertions(+), 2 deletions(-) > > diff --git a/include/linux/slab.h b/include/linux/slab.h > index 10fd0a8c816a..6ce826d8194d 100644 > --- a/include/linux/slab.h > +++ b/include/linux/slab.h > @@ -181,7 +181,7 @@ int kmem_cache_shrink(struct kmem_cache *s); > /* > * Common kmalloc functions provided by all allocators > */ > -__must_check > +__must_check __alloc_size(2) > void *krealloc(const void *objp, size_t new_size, gfp_t flags); > void kfree(const void *objp); > void kfree_sensitive(const void *objp); > @@ -426,6 +426,7 @@ static __always_inline unsigned int __kmalloc_index(size_t size, > #define kmalloc_index(s) __kmalloc_index(s, true) > #endif /* !CONFIG_SLOB */ > > +__alloc_size(1) > void *__kmalloc(size_t size, gfp_t flags) __assume_kmalloc_alignment __malloc; > void *kmem_cache_alloc(struct kmem_cache *s, gfp_t flags) __assume_kmalloc_alignment __malloc; > void kmem_cache_free(struct kmem_cache *s, void *objp); > @@ -450,6 +451,7 @@ static __always_inline void kfree_bulk(size_t size, void **p) > } > > #ifdef CONFIG_NUMA > +__alloc_size(1) > void *__kmalloc_node(size_t size, gfp_t flags, int node) __assume_slab_alignment __malloc; > void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t flags, int node) > __assume_slab_alignment __malloc; > @@ -574,6 +576,7 @@ static __always_inline void *kmalloc_large(size_t size, gfp_t flags) > * Try really hard to succeed the allocation but fail > * eventually. > */ > +__alloc_size(1) > static __always_inline void *kmalloc(size_t size, gfp_t flags) > { > if (__builtin_constant_p(size)) { > @@ -596,6 +599,7 @@ static __always_inline void *kmalloc(size_t size, gfp_t flags) > return __kmalloc(size, flags); > } > > +__alloc_size(1) > static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node) > { > #ifndef CONFIG_SLOB > @@ -620,6 +624,7 @@ static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node) > * @size: element size. > * @flags: the type of memory to allocate (see kmalloc). > */ > +__alloc_size(1, 2) > static inline void *kmalloc_array(size_t n, size_t size, gfp_t flags) > { > size_t bytes; > @@ -638,7 +643,7 @@ static inline void *kmalloc_array(size_t n, size_t size, gfp_t flags) > * @new_size: new size of a single member of the array > * @flags: the type of memory to allocate (see kmalloc) > */ > -__must_check > +__must_check __alloc_size(2, 3) > static inline void *krealloc_array(void *p, size_t new_n, size_t new_size, > gfp_t flags) > { > @@ -656,6 +661,7 @@ static inline void *krealloc_array(void *p, size_t new_n, size_t new_size, > * @size: element size. > * @flags: the type of memory to allocate (see kmalloc). > */ > +__alloc_size(1, 2) > static inline void *kcalloc(size_t n, size_t size, gfp_t flags) > { > return kmalloc_array(n, size, flags | __GFP_ZERO); > @@ -685,6 +691,7 @@ static inline void *kmalloc_array_node(size_t n, size_t size, gfp_t flags, > return __kmalloc_node(bytes, flags, node); > } > > +__alloc_size(1, 2) > static inline void *kcalloc_node(size_t n, size_t size, gfp_t flags, int node) > { > return kmalloc_array_node(n, size, flags | __GFP_ZERO, node); > @@ -718,6 +725,7 @@ static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags) > * @size: how many bytes of memory are required. > * @flags: the type of memory to allocate (see kmalloc). > */ > +__alloc_size(1) > static inline void *kzalloc(size_t size, gfp_t flags) > { > return kmalloc(size, flags | __GFP_ZERO); > @@ -729,25 +737,31 @@ static inline void *kzalloc(size_t size, gfp_t flags) > * @flags: the type of memory to allocate (see kmalloc). > * @node: memory node from which to allocate > */ > +__alloc_size(1) > static inline void *kzalloc_node(size_t size, gfp_t flags, int node) > { > return kmalloc_node(size, flags | __GFP_ZERO, node); > } > > +__alloc_size(1) > extern void *kvmalloc_node(size_t size, gfp_t flags, int node); > +__alloc_size(1) > static inline void *kvmalloc(size_t size, gfp_t flags) > { > return kvmalloc_node(size, flags, NUMA_NO_NODE); > } > +__alloc_size(1) > static inline void *kvzalloc_node(size_t size, gfp_t flags, int node) > { > return kvmalloc_node(size, flags | __GFP_ZERO, node); > } > +__alloc_size(1) > static inline void *kvzalloc(size_t size, gfp_t flags) > { > return kvmalloc(size, flags | __GFP_ZERO); > } > > +__alloc_size(1, 2) > static inline void *kvmalloc_array(size_t n, size_t size, gfp_t flags) > { > size_t bytes; > @@ -758,11 +772,13 @@ static inline void *kvmalloc_array(size_t n, size_t size, gfp_t flags) > return kvmalloc(bytes, flags); > } > > +__alloc_size(1, 2) > static inline void *kvcalloc(size_t n, size_t size, gfp_t flags) > { > return kvmalloc_array(n, size, flags | __GFP_ZERO); > } > > +__alloc_size(3) > extern void *kvrealloc(const void *p, size_t oldsize, size_t newsize, > gfp_t flags); > extern void kvfree(const void *addr); > -- -- Thanks, ~Nick Desaulniers