From: Kees Cook <keescook@xxxxxxxxxxxx> Subject: slab: add __alloc_size attributes for better bounds checking 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. Link: https://lkml.kernel.org/r/20210818214021.2476230-5-keescook@xxxxxxxxxxxx Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> Co-developed-by: Daniel Micay <danielmicay@xxxxxxxxx> Signed-off-by: Daniel Micay <danielmicay@xxxxxxxxx> Reviewed-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> Cc: Christoph Lameter <cl@xxxxxxxxx> Cc: Pekka Enberg <penberg@xxxxxxxxxx> Cc: David Rientjes <rientjes@xxxxxxxxxx> Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> Cc: Vlastimil Babka <vbabka@xxxxxxx> Cc: Andy Whitcroft <apw@xxxxxxxxxxxxx> Cc: Dennis Zhou <dennis@xxxxxxxxxx> Cc: Dwaipayan Ray <dwaipayanray1@xxxxxxxxx> Cc: Joe Perches <joe@xxxxxxxxxxx> Cc: Lukas Bulwahn <lukas.bulwahn@xxxxxxxxx> Cc: Miguel Ojeda <ojeda@xxxxxxxxxx> Cc: Nathan Chancellor <nathan@xxxxxxxxxx> Cc: Tejun Heo <tj@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/slab.h | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) --- a/include/linux/slab.h~slab-add-__alloc_size-attributes-for-better-bounds-checking +++ a/include/linux/slab.h @@ -181,7 +181,7 @@ int kmem_cache_shrink(struct kmem_cache /* * 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 __km #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(s } #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_lar * 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(siz 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_nod * @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 * @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 * @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(s 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(st * @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, * @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_ 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); _
