As already done in GrapheneOS, add the __alloc_size attribute for
appropriate percpu allocator interfaces, to provide additional hinting for
better bounds checking, assisting CONFIG_FORTIFY_SOURCE and other compiler
optimizations.
Note that due to the implementation of the percpu API, this is unlikely
to ever actually provide compile-time checking beyond very simple non-SMP
builds. But, since they are technically allocators, mark them as such.
Cc: Dennis Zhou <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Christoph Lameter <[email protected]>
Cc: Andy Whitcroft <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Dwaipayan Ray <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Cc: Lukas Bulwahn <[email protected]>
Cc: Miguel Ojeda <[email protected]>
Cc: Nathan Chancellor <[email protected]>
Cc: Nick Desaulniers <[email protected]>
Cc: Pekka Enberg <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Co-developed-by: Daniel Micay <[email protected]>
Signed-off-by: Daniel Micay <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
---
include/linux/percpu.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/include/linux/percpu.h b/include/linux/percpu.h
index 5e76af742c80..98a9371133f8 100644
--- a/include/linux/percpu.h
+++ b/include/linux/percpu.h
@@ -123,7 +123,7 @@ extern int __init pcpu_page_first_chunk(size_t reserved_size,
pcpu_fc_populate_pte_fn_t populate_pte_fn);
#endif
-extern void __percpu *__alloc_reserved_percpu(size_t size, size_t align);
+extern void __percpu *__alloc_reserved_percpu(size_t size, size_t align) __alloc_size(1);
extern bool __is_kernel_percpu_address(unsigned long addr, unsigned long *can_addr);
extern bool is_kernel_percpu_address(unsigned long addr);
@@ -131,8 +131,8 @@ extern bool is_kernel_percpu_address(unsigned long addr);
extern void __init setup_per_cpu_areas(void);
#endif
-extern void __percpu *__alloc_percpu_gfp(size_t size, size_t align, gfp_t gfp);
-extern void __percpu *__alloc_percpu(size_t size, size_t align);
+extern void __percpu *__alloc_percpu_gfp(size_t size, size_t align, gfp_t gfp) __alloc_size(1);
+extern void __percpu *__alloc_percpu(size_t size, size_t align) __alloc_size(1);
extern void free_percpu(void __percpu *__pdata);
extern phys_addr_t per_cpu_ptr_to_phys(void *addr);
--
2.30.2
Hello,
On Thu, Sep 30, 2021 at 03:27:04PM -0700, Kees Cook wrote:
> As already done in GrapheneOS, add the __alloc_size attribute for
> appropriate percpu allocator interfaces, to provide additional hinting for
> better bounds checking, assisting CONFIG_FORTIFY_SOURCE and other compiler
> optimizations.
>
> Note that due to the implementation of the percpu API, this is unlikely
> to ever actually provide compile-time checking beyond very simple non-SMP
> builds. But, since they are technically allocators, mark them as such.
>
> Cc: Dennis Zhou <[email protected]>
> Cc: Tejun Heo <[email protected]>
> Cc: Christoph Lameter <[email protected]>
> Cc: Andy Whitcroft <[email protected]>
> Cc: David Rientjes <[email protected]>
> Cc: Dwaipayan Ray <[email protected]>
> Cc: Joe Perches <[email protected]>
> Cc: Joonsoo Kim <[email protected]>
> Cc: Lukas Bulwahn <[email protected]>
> Cc: Miguel Ojeda <[email protected]>
> Cc: Nathan Chancellor <[email protected]>
> Cc: Nick Desaulniers <[email protected]>
> Cc: Pekka Enberg <[email protected]>
> Cc: Vlastimil Babka <[email protected]>
> Co-developed-by: Daniel Micay <[email protected]>
> Signed-off-by: Daniel Micay <[email protected]>
> Signed-off-by: Kees Cook <[email protected]>
Thanks for updating the commit log.
Acked-by: Dennis Zhou <[email protected]>
Thanks,
Dennis
> ---
> include/linux/percpu.h | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/include/linux/percpu.h b/include/linux/percpu.h
> index 5e76af742c80..98a9371133f8 100644
> --- a/include/linux/percpu.h
> +++ b/include/linux/percpu.h
> @@ -123,7 +123,7 @@ extern int __init pcpu_page_first_chunk(size_t reserved_size,
> pcpu_fc_populate_pte_fn_t populate_pte_fn);
> #endif
>
> -extern void __percpu *__alloc_reserved_percpu(size_t size, size_t align);
> +extern void __percpu *__alloc_reserved_percpu(size_t size, size_t align) __alloc_size(1);
> extern bool __is_kernel_percpu_address(unsigned long addr, unsigned long *can_addr);
> extern bool is_kernel_percpu_address(unsigned long addr);
>
> @@ -131,8 +131,8 @@ extern bool is_kernel_percpu_address(unsigned long addr);
> extern void __init setup_per_cpu_areas(void);
> #endif
>
> -extern void __percpu *__alloc_percpu_gfp(size_t size, size_t align, gfp_t gfp);
> -extern void __percpu *__alloc_percpu(size_t size, size_t align);
> +extern void __percpu *__alloc_percpu_gfp(size_t size, size_t align, gfp_t gfp) __alloc_size(1);
> +extern void __percpu *__alloc_percpu(size_t size, size_t align) __alloc_size(1);
> extern void free_percpu(void __percpu *__pdata);
> extern phys_addr_t per_cpu_ptr_to_phys(void *addr);
>
> --
> 2.30.2
>