2023-10-03 23:26:05

by Kees Cook

Subject: [PATCH] nvmet-fc: Annotate struct nvmet_fc_tgt_queue 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 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 <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Sagi Grimberg <[email protected]>
Cc: Chaitanya Kulkarni <[email protected]>
Cc: [email protected]
Link: https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci [1]
Signed-off-by: Kees Cook <[email protected]>
---
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

2023-10-04 01:45:47

by Gustavo A. R. Silva

Subject: Re: [PATCH] nvmet-fc: Annotate struct nvmet_fc_tgt_queue with __counted_by

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 <[email protected]>
> Cc: Christoph Hellwig <[email protected]>
> Cc: Sagi Grimberg <[email protected]>
> Cc: Chaitanya Kulkarni <[email protected]>
> Cc: [email protected]
> Link: https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci [1]
> Signed-off-by: Kees Cook <[email protected]>

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

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 {

2023-10-04 06:33:56

by Chaitanya Kulkarni

Subject: Re: [PATCH] nvmet-fc: Annotate struct nvmet_fc_tgt_queue with __counted_by

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 <[email protected]>
> Cc: Christoph Hellwig <[email protected]>
> Cc: Sagi Grimberg <[email protected]>
> Cc: Chaitanya Kulkarni <[email protected]>
> Cc: [email protected]
> Link: https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci [1]
> Signed-off-by: Kees Cook <[email protected]>
> ---
>

Looks good.

Reviewed-by: Chaitanya Kulkarni <[email protected]>

-ck

2023-10-05 14:57:33

by Christoph Hellwig

Subject: Re: [PATCH] nvmet-fc: Annotate struct nvmet_fc_tgt_queue with __counted_by

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.