UPSTREAM: 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/20210930222704.2631604-5-keescook@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Co-developed-by: Daniel Micay <danielmicay@gmail.com>
Signed-off-by: Daniel Micay <danielmicay@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Dwaipayan Ray <dwaipayanray1@gmail.com>
Cc: Joe Perches <joe@perches.com>
Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Alexandre Bounine <alex.bou9@gmail.com>
Cc: Gustavo A. R. Silva <gustavoars@kernel.org>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jing Xiangfeng <jingxiangfeng@huawei.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: kernel test robot <lkp@intel.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
(cherry picked from commit c37495d625)
[Note: only the kzalloc portion of this commit is being applied, in a
 quest to find the offending part of the commit as part of this is
 breaking cuttlefish builds - gregkh]
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: Ib456a932d84a0112b476789b82f77fa4422ca72d

include/linux/slab.h

@@ -717,7 +717,7 @@ 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).
  */
-static inline void *kzalloc(size_t size, gfp_t flags)
+static inline __alloc_size(1) void *kzalloc(size_t size, gfp_t flags)
 {
 	return kmalloc(size, flags | __GFP_ZERO);
 }