[PATCH v3 5/8] mm/kvmalloc: Add __alloc_size attributes for better bounds checking

[Kees Cook <keescook@xxxxxxxxxxxx>]

As already done in GrapheneOS, add the __alloc_size attribute for regular
kvmalloc interfaces, to provide additional hinting for better bounds
checking, assisting CONFIG_FORTIFY_SOURCE and other compiler
optimizations.

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>
Co-developed-by: Daniel Micay <danielmicay@xxxxxxxxx>
Signed-off-by: Daniel Micay <danielmicay@xxxxxxxxx>
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Reviewed-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
---
 include/linux/mm.h | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 73a52aba448f..03dfb466d4f5 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -799,21 +799,21 @@ static inline int is_vmalloc_or_module_addr(const void *x)
 }
 #endif
 
-extern void *kvmalloc_node(size_t size, gfp_t flags, int node);
-static inline void *kvmalloc(size_t size, gfp_t flags)
+extern void *kvmalloc_node(size_t size, gfp_t flags, int node) __alloc_size(1);
+static inline __alloc_size(1) void *kvmalloc(size_t size, gfp_t flags)
 {
 	return kvmalloc_node(size, flags, NUMA_NO_NODE);
 }
-static inline void *kvzalloc_node(size_t size, gfp_t flags, int node)
+static inline __alloc_size(1) void *kvzalloc_node(size_t size, gfp_t flags, int node)
 {
 	return kvmalloc_node(size, flags | __GFP_ZERO, node);
 }
-static inline void *kvzalloc(size_t size, gfp_t flags)
+static inline __alloc_size(1) void *kvzalloc(size_t size, gfp_t flags)
 {
 	return kvmalloc(size, flags | __GFP_ZERO);
 }
 
-static inline void *kvmalloc_array(size_t n, size_t size, gfp_t flags)
+static inline __alloc_size(1, 2) void *kvmalloc_array(size_t n, size_t size, gfp_t flags)
 {
 	size_t bytes;
 
@@ -823,13 +823,13 @@ static inline void *kvmalloc_array(size_t n, size_t size, gfp_t flags)
 	return kvmalloc(bytes, flags);
 }
 
-static inline void *kvcalloc(size_t n, size_t size, gfp_t flags)
+static inline __alloc_size(1, 2) void *kvcalloc(size_t n, size_t size, gfp_t flags)
 {
 	return kvmalloc_array(n, size, flags | __GFP_ZERO);
 }
 
-extern void *kvrealloc(const void *p, size_t oldsize, size_t newsize,
-		gfp_t flags);
+extern void *kvrealloc(const void *p, size_t oldsize, size_t newsize, gfp_t flags)
+		      __alloc_size(3);
 extern void kvfree(const void *addr);
 extern void kvfree_sensitive(const void *addr, size_t len);
 
-- 
2.30.2