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 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 nvmet_fc_tgt_queue.

Cc: James Smart <james.smart@broadcom.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Chaitanya Kulkarni <kch@nvidia.com>
Cc: linux-nvme@lists.infradead.org
Link: https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci [1]
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/nvme/target/fc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/nvme/target/fc.c b/drivers/nvme/target/fc.c
index 1ab6601fdd5c..0fa2d658cdeb 100644
--- a/drivers/nvme/target/fc.c
+++ b/drivers/nvme/target/fc.c
@@ -146,7 +146,7 @@ struct nvmet_fc_tgt_queue {
 	struct workqueue_struct		*work_q;
 	struct kref			ref;
 	struct rcu_head			rcu;
-	struct nvmet_fc_fcp_iod		fod[];		/* array of fcp_iods */
+	struct nvmet_fc_fcp_iod		fod[] __counted_by(sqsize); /* array of fcp_iods */
 } __aligned(sizeof(unsigned long long));
 
 struct nvmet_fc_hostport {
-- 
2.34.1

On Tue, Oct 03, 2023 at 04:25:11PM -0700, Kees Cook wrote:
>  	struct workqueue_struct		*work_q;
>  	struct kref			ref;
>  	struct rcu_head			rcu;
> -	struct nvmet_fc_fcp_iod		fod[];		/* array of fcp_iods */
> +	struct nvmet_fc_fcp_iod		fod[] __counted_by(sqsize); /* array of fcp_iods */

Please move the comment up to not spill over the end of the line.

Otherwise this looks good.

On 10/3/23 16:25, 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 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 nvmet_fc_tgt_queue.
>
> Cc: James Smart <james.smart@broadcom.com>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: Sagi Grimberg <sagi@grimberg.me>
> Cc: Chaitanya Kulkarni <kch@nvidia.com>
> Cc: linux-nvme@lists.infradead.org
> Link: https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci [1]
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
>   

Looks good.

Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>

-ck

On 10/4/23 01:25, 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 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 nvmet_fc_tgt_queue.
> 
> Cc: James Smart <james.smart@broadcom.com>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: Sagi Grimberg <sagi@grimberg.me>
> Cc: Chaitanya Kulkarni <kch@nvidia.com>
> Cc: linux-nvme@lists.infradead.org
> Link: https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci [1]
> Signed-off-by: Kees Cook <keescook@chromium.org>

Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Thanks
--
Gustavo

> ---
>   drivers/nvme/target/fc.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/nvme/target/fc.c b/drivers/nvme/target/fc.c
> index 1ab6601fdd5c..0fa2d658cdeb 100644
> --- a/drivers/nvme/target/fc.c
> +++ b/drivers/nvme/target/fc.c
> @@ -146,7 +146,7 @@ struct nvmet_fc_tgt_queue {
>   	struct workqueue_struct		*work_q;
>   	struct kref			ref;
>   	struct rcu_head			rcu;
> -	struct nvmet_fc_fcp_iod		fod[];		/* array of fcp_iods */
> +	struct nvmet_fc_fcp_iod		fod[] __counted_by(sqsize); /* array of fcp_iods */
>   } __aligned(sizeof(unsigned long long));
>   
>   struct nvmet_fc_hostport {