[patch 035/262] slab: add __alloc_size attributes for better bounds checking

Andrew Morton
2021-11-05T20:36:30Z

From: Kees Cook <keescook@chromium.org>
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/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>
---

include/linux/slab.h | 61 ++++++++++++++++++++++-------------------
1 file changed, 33 insertions(+), 28 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
*/
-void * __must_check krealloc(const void *objp, size_t new_size, gfp_t flags);
+void * __must_check krealloc(const void *objp, size_t new_size, gfp_t flags) __alloc_size(2);
void kfree(const void *objp);
void kfree_sensitive(const void *objp);
size_t __ksize(const void *objp);
@@ -425,7 +425,7 @@ static __always_inline unsigned int __km
#define kmalloc_index(s) __kmalloc_index(s, true)
#endif /* !CONFIG_SLOB */

-void *__kmalloc(size_t size, gfp_t flags) __assume_kmalloc_alignment __malloc;
+void *__kmalloc(size_t size, gfp_t flags) __assume_kmalloc_alignment __alloc_size(1);
void *kmem_cache_alloc(struct kmem_cache *s, gfp_t flags) __assume_slab_alignment __malloc;
void kmem_cache_free(struct kmem_cache *s, void *objp);

@@ -449,11 +449,12 @@ static __always_inline void kfree_bulk(s
}

#ifdef CONFIG_NUMA
-void *__kmalloc_node(size_t size, gfp_t flags, int node) __assume_kmalloc_alignment __malloc;
+void *__kmalloc_node(size_t size, gfp_t flags, int node) __assume_kmalloc_alignment
+ __alloc_size(1);
void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t flags, int node) __assume_slab_alignment
__malloc;
#else
-static __always_inline void *__kmalloc_node(size_t size, gfp_t flags, int node)
+static __always_inline __alloc_size(1) void *__kmalloc_node(size_t size, gfp_t flags, int node)
{
return __kmalloc(size, flags);
}
@@ -466,23 +467,23 @@ static __always_inline void *kmem_cache_

#ifdef CONFIG_TRACING
extern void *kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t flags, size_t size)
- __assume_slab_alignment __malloc;
+ __assume_slab_alignment __alloc_size(3);

#ifdef CONFIG_NUMA
extern void *kmem_cache_alloc_node_trace(struct kmem_cache *s, gfp_t gfpflags,
- int node, size_t size) __assume_slab_alignment __malloc;
+ int node, size_t size) __assume_slab_alignment
+ __alloc_size(4);
#else
-static __always_inline void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
- gfp_t gfpflags, int node,
- size_t size)
+static __always_inline __alloc_size(4) void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
+ gfp_t gfpflags, int node, size_t size)
{
return kmem_cache_alloc_trace(s, gfpflags, size);
}
#endif /* CONFIG_NUMA */

#else /* CONFIG_TRACING */
-static __always_inline void *kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t flags,
- size_t size)
+static __always_inline __alloc_size(3) void *kmem_cache_alloc_trace(struct kmem_cache *s,
+ gfp_t flags, size_t size)
{
void *ret = kmem_cache_alloc(s, flags);

@@ -501,19 +502,20 @@ static __always_inline void *kmem_cache_
#endif /* CONFIG_TRACING */

extern void *kmalloc_order(size_t size, gfp_t flags, unsigned int order) __assume_page_alignment
- __malloc;
+ __alloc_size(1);

#ifdef CONFIG_TRACING
extern void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
- __assume_page_alignment __malloc;
+ __assume_page_alignment __alloc_size(1);
#else
-static __always_inline void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
+static __always_inline __alloc_size(1) void *kmalloc_order_trace(size_t size, gfp_t flags,
+ unsigned int order)
{
return kmalloc_order(size, flags, order);
}
#endif

-static __always_inline void *kmalloc_large(size_t size, gfp_t flags)
+static __always_inline __alloc_size(1) void *kmalloc_large(size_t size, gfp_t flags)
{
unsigned int order = get_order(size);
return kmalloc_order_trace(size, flags, order);
@@ -573,7 +575,7 @@ static __always_inline void *kmalloc_lar
* Try really hard to succeed the allocation but fail
* eventually.
*/
-static __always_inline void *kmalloc(size_t size, gfp_t flags)
+static __always_inline __alloc_size(1) void *kmalloc(size_t size, gfp_t flags)
{
if (__builtin_constant_p(size)) {
#ifndef CONFIG_SLOB
@@ -595,7 +597,7 @@ static __always_inline void *kmalloc(siz
return __kmalloc(size, flags);
}

-static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
+static __always_inline __alloc_size(1) void *kmalloc_node(size_t size, gfp_t flags, int node)
{
#ifndef CONFIG_SLOB
if (__builtin_constant_p(size) &&
@@ -619,7 +621,7 @@ static __always_inline void *kmalloc_nod
* @size: element size.
* @flags: the type of memory to allocate (see kmalloc).
*/
-static inline void *kmalloc_array(size_t n, size_t size, gfp_t flags)
+static inline __alloc_size(1, 2) void *kmalloc_array(size_t n, size_t size, gfp_t flags)
{
size_t bytes;

@@ -637,8 +639,10 @@ 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)
*/
-static inline void * __must_check krealloc_array(void *p, size_t new_n, size_t new_size,
- gfp_t flags)
+static inline __alloc_size(2, 3) void * __must_check krealloc_array(void *p,
+ size_t new_n,
+ size_t new_size,
+ gfp_t flags)
{
size_t bytes;

@@ -654,7 +658,7 @@ static inline void * __must_check kreall
* @size: element size.
* @flags: the type of memory to allocate (see kmalloc).
*/
-static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
+static inline __alloc_size(1, 2) void *kcalloc(size_t n, size_t size, gfp_t flags)
{
return kmalloc_array(n, size, flags | __GFP_ZERO);
}
@@ -667,12 +671,13 @@ static inline void *kcalloc(size_t n, si
* allocator where we care about the real place the memory allocation
* request comes from.
*/
-extern void *__kmalloc_track_caller(size_t size, gfp_t flags, unsigned long caller);
+extern void *__kmalloc_track_caller(size_t size, gfp_t flags, unsigned long caller)
+ __alloc_size(1);
#define kmalloc_track_caller(size, flags) \
__kmalloc_track_caller(size, flags, _RET_IP_)

-static inline void *kmalloc_array_node(size_t n, size_t size, gfp_t flags,
- int node)
+static inline __alloc_size(1, 2) void *kmalloc_array_node(size_t n, size_t size, gfp_t flags,
+ int node)
{
size_t bytes;

@@ -683,7 +688,7 @@ static inline void *kmalloc_array_node(s
return __kmalloc_node(bytes, flags, node);
}

-static inline void *kcalloc_node(size_t n, size_t size, gfp_t flags, int node)
+static inline __alloc_size(1, 2) void *kcalloc_node(size_t n, size_t size, gfp_t flags, int node)
{
return kmalloc_array_node(n, size, flags | __GFP_ZERO, node);
}
@@ -691,7 +696,7 @@ static inline void *kcalloc_node(size_t

#ifdef CONFIG_NUMA
extern void *__kmalloc_node_track_caller(size_t size, gfp_t flags, int node,
- unsigned long caller);
+ unsigned long caller) __alloc_size(1);
#define kmalloc_node_track_caller(size, flags, node) \
__kmalloc_node_track_caller(size, flags, node, \
_RET_IP_)
@@ -716,7 +721,7 @@ static inline void *kmem_cache_zalloc(st
* @size: how many bytes of memory are required.
* @flags: the type of memory to allocate (see kmalloc).
*/
-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);
}
@@ -727,7 +732,7 @@ static inline void *kzalloc(size_t size,
* @flags: the type of memory to allocate (see kmalloc).
* @node: memory node from which to allocate
*/
-static inline void *kzalloc_node(size_t size, gfp_t flags, int node)
+static inline __alloc_size(1) void *kzalloc_node(size_t size, gfp_t flags, int node)
{
return kmalloc_node(size, flags | __GFP_ZERO, node);
}
_