Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
(for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).
As found with Coccinelle[1], add __counted_by for struct gcov_iterator.
[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
Cc: Peter Oberparleiter <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
---
kernel/gcov/fs.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/gcov/fs.c b/kernel/gcov/fs.c
index 5c3086cad8f9..01520689b57c 100644
--- a/kernel/gcov/fs.c
+++ b/kernel/gcov/fs.c
@@ -99,7 +99,7 @@ struct gcov_iterator {
struct gcov_info *info;
size_t size;
loff_t pos;
- char buffer[];
+ char buffer[] __counted_by(size);
};
/**
--
2.34.1
On 9/22/23 11:52, Kees Cook wrote:
> Prepare for the coming implementation by GCC and Clang of the __counted_by
> attribute. Flexible array members annotated with __counted_by can have
> their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
> (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> functions).
>
> As found with Coccinelle[1], add __counted_by for struct gcov_iterator.
>
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
>
> Cc: Peter Oberparleiter <[email protected]>
> Signed-off-by: Kees Cook <[email protected]>
Reviewed-by: Gustavo A. R. Silva <[email protected]>
Thanks
--
Gustavo
> ---
> kernel/gcov/fs.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/gcov/fs.c b/kernel/gcov/fs.c
> index 5c3086cad8f9..01520689b57c 100644
> --- a/kernel/gcov/fs.c
> +++ b/kernel/gcov/fs.c
> @@ -99,7 +99,7 @@ struct gcov_iterator {
> struct gcov_info *info;
> size_t size;
> loff_t pos;
> - char buffer[];
> + char buffer[] __counted_by(size);
> };
>
> /**
On 22.09.2023 19:52, Kees Cook wrote:
> Prepare for the coming implementation by GCC and Clang of the __counted_by
> attribute. Flexible array members annotated with __counted_by can have
> their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
> (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> functions).
>
> As found with Coccinelle[1], add __counted_by for struct gcov_iterator.
>
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
>
> Cc: Peter Oberparleiter <[email protected]>
> Signed-off-by: Kees Cook <[email protected]>
Looks good to me!
Reviewed-by: Peter Oberparleiter <[email protected]>
Andrew, could you add this patch via your tree?
--
Peter Oberparleiter
Linux on IBM Z Development - IBM Germany R&D