2023-09-22 23:17:21

by Kees Cook

Subject: [PATCH] libata: Annotate struct ata_cpr_log 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 ata_cpr_log.

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

Cc: Damien Le Moal <[email protected]>
Cc: [email protected]
Signed-off-by: Kees Cook <[email protected]>
---
include/linux/libata.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/libata.h b/include/linux/libata.h
index 3c17a5053f00..f91e8e7f1c00 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -656,7 +656,7 @@ struct ata_cpr {

struct ata_cpr_log {
u8 nr_cpr;
- struct ata_cpr cpr[];
+ struct ata_cpr cpr[] __counted_by(nr_cpr);
};

struct ata_device {
--
2.34.1

2023-09-23 15:03:57

by Gustavo A. R. Silva

Subject: Re: [PATCH] libata: Annotate struct ata_cpr_log with __counted_by

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 ata_cpr_log.
>
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
>
> Cc: Damien Le Moal <[email protected]>
> Cc: [email protected]
> Signed-off-by: Kees Cook <[email protected]>

Reviewed-by: Gustavo A. R. Silva <[email protected]>

Thanks
--
Gustavo

> ---
> include/linux/libata.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/linux/libata.h b/include/linux/libata.h
> index 3c17a5053f00..f91e8e7f1c00 100644
> --- a/include/linux/libata.h
> +++ b/include/linux/libata.h
> @@ -656,7 +656,7 @@ struct ata_cpr {
>
> struct ata_cpr_log {
> u8 nr_cpr;
> - struct ata_cpr cpr[];
> + struct ata_cpr cpr[] __counted_by(nr_cpr);
> };
>
> struct ata_device {

2023-09-25 07:11:35

by Damien Le Moal

Subject: Re: [PATCH] libata: Annotate struct ata_cpr_log with __counted_by

On 2023/09/22 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 ata_cpr_log.
>
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
>
> Cc: Damien Le Moal <[email protected]>
> Cc: [email protected]
> Signed-off-by: Kees Cook <[email protected]>

Applied to for-6.7. Thanks !

--
Damien Le Moal
Western Digital Research