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slab: add __alloc_size attributes for better bounds checking
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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>
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@kees @torvalds
kees authored and torvalds committed Nov 6, 2021
1 parent 72d6722 commit c37495d
Showing 1 changed file with 33 additions and 28 deletions.
61 changes: 33 additions & 28 deletions include/linux/slab.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -181,7 +181,7 @@ int kmem_cache_shrink(struct kmem_cache *s);
/*
* 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);
Expand Down Expand Up @@ -425,7 +425,7 @@ static __always_inline unsigned int __kmalloc_index(size_t size,
#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);

Expand All @@ -449,11 +449,12 @@ static __always_inline void kfree_bulk(size_t size, void **p)
}

#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);
}
Expand All @@ -466,23 +467,23 @@ static __always_inline void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t f

#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);

Expand All @@ -501,19 +502,20 @@ static __always_inline void *kmem_cache_alloc_node_trace(struct kmem_cache *s, g
#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);
Expand Down Expand Up @@ -573,7 +575,7 @@ static __always_inline void *kmalloc_large(size_t size, gfp_t flags)
* 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
Expand All @@ -595,7 +597,7 @@ static __always_inline void *kmalloc(size_t size, gfp_t flags)
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) &&
Expand All @@ -619,7 +621,7 @@ 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).
*/
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;

Expand All @@ -637,8 +639,10 @@ 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)
*/
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;

Expand All @@ -654,7 +658,7 @@ static inline void * __must_check krealloc_array(void *p, size_t new_n, size_t n
* @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);
}
Expand All @@ -667,12 +671,13 @@ static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
* 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;

Expand All @@ -683,15 +688,15 @@ static inline void *kmalloc_array_node(size_t n, size_t size, gfp_t flags,
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);
}


#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_)
Expand All @@ -716,7 +721,7 @@ 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);
}
Expand All @@ -727,7 +732,7 @@ 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
*/
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);
}
Expand Down

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