2023-09-16 06:11:11

by Kees Cook

Subject: [PATCH] ocfs2: Annotate struct ocfs2_slot_info with __counted_by

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 ocfs2_slot_info.

[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Cc: Mark Fasheh <[email protected]>
Cc: Joel Becker <[email protected]>
Cc: Joseph Qi <[email protected]>
Cc: [email protected]
Signed-off-by: Kees Cook <[email protected]>
---
fs/ocfs2/slot_map.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ocfs2/slot_map.c b/fs/ocfs2/slot_map.c
index da7718cef735..e544c704b583 100644
--- a/fs/ocfs2/slot_map.c
+++ b/fs/ocfs2/slot_map.c
@@ -37,7 +37,7 @@ struct ocfs2_slot_info {
unsigned int si_blocks;
struct buffer_head **si_bh;
unsigned int si_num_slots;
- struct ocfs2_slot si_slots[];
+ struct ocfs2_slot si_slots[] __counted_by(si_num_slots);
};


--
2.34.1

2023-09-17 15:05:10

by Joseph Qi

Subject: Re: [PATCH] ocfs2: Annotate struct ocfs2_slot_info with __counted_by

On 9/16/23 4:15 AM, 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 ocfs2_slot_info.
>
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
>
> Cc: Mark Fasheh <[email protected]>
> Cc: Joel Becker <[email protected]>
> Cc: Joseph Qi <[email protected]>
> Cc: [email protected]
> Signed-off-by: Kees Cook <[email protected]>

Reviewed-by: Joseph Qi <[email protected]>
> ---
> fs/ocfs2/slot_map.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/ocfs2/slot_map.c b/fs/ocfs2/slot_map.c
> index da7718cef735..e544c704b583 100644
> --- a/fs/ocfs2/slot_map.c
> +++ b/fs/ocfs2/slot_map.c
> @@ -37,7 +37,7 @@ struct ocfs2_slot_info {
> unsigned int si_blocks;
> struct buffer_head **si_bh;
> unsigned int si_num_slots;
> - struct ocfs2_slot si_slots[];
> + struct ocfs2_slot si_slots[] __counted_by(si_num_slots);
> };
>
>

2023-09-30 03:41:04

by Kees Cook

Subject: Re: [PATCH] ocfs2: Annotate struct ocfs2_slot_info with __counted_by

On Fri, 15 Sep 2023 13:15:23 -0700, 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 ocfs2_slot_info.
>
> [...]

Applied to for-next/hardening, thanks!

[1/1] ocfs2: Annotate struct ocfs2_slot_info with __counted_by
https://git.kernel.org/kees/c/7c993785ae63

Take care,

--
Kees Cook