2023-09-22 19:31:25

by Kees Cook

[permalink] [raw]
Subject: [PATCH] libnvdimm: Annotate struct nd_region 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 nd_region.
Additionally, since the element count member must be set before accessing
the annotated flexible array member, move its initialization earlier.

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

Cc: Dan Williams <[email protected]>
Cc: Vishal Verma <[email protected]>
Cc: Dave Jiang <[email protected]>
Cc: Ira Weiny <[email protected]>
Cc: [email protected]
Signed-off-by: Kees Cook <[email protected]>
---
drivers/nvdimm/nd.h | 2 +-
drivers/nvdimm/region_devs.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
index e8b9d27dbb3c..ae2078eb6a62 100644
--- a/drivers/nvdimm/nd.h
+++ b/drivers/nvdimm/nd.h
@@ -422,7 +422,7 @@ struct nd_region {
struct nd_interleave_set *nd_set;
struct nd_percpu_lane __percpu *lane;
int (*flush)(struct nd_region *nd_region, struct bio *bio);
- struct nd_mapping mapping[];
+ struct nd_mapping mapping[] __counted_by(ndr_mappings);
};

static inline bool nsl_validate_nlabel(struct nd_region *nd_region,
diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
index 0a81f87f6f6c..5be65fce85cf 100644
--- a/drivers/nvdimm/region_devs.c
+++ b/drivers/nvdimm/region_devs.c
@@ -1028,6 +1028,7 @@ static struct nd_region *nd_region_create(struct nvdimm_bus *nvdimm_bus,

if (!nd_region)
return NULL;
+ nd_region->ndr_mappings = ndr_desc->num_mappings;
/* CXL pre-assigns memregion ids before creating nvdimm regions */
if (test_bit(ND_REGION_CXL, &ndr_desc->flags)) {
nd_region->id = ndr_desc->memregion;
@@ -1062,7 +1063,6 @@ static struct nd_region *nd_region_create(struct nvdimm_bus *nvdimm_bus,

get_device(&nvdimm->dev);
}
- nd_region->ndr_mappings = ndr_desc->num_mappings;
nd_region->provider_data = ndr_desc->provider_data;
nd_region->nd_set = ndr_desc->nd_set;
nd_region->num_lanes = ndr_desc->num_lanes;
--
2.34.1


2023-09-22 23:18:42

by Verma, Vishal L

[permalink] [raw]
Subject: Re: [PATCH] libnvdimm: Annotate struct nd_region with __counted_by

On Fri, 2023-09-22 at 10:52 -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 nd_region.
> Additionally, since the element count member must be set before
> accessing
> the annotated flexible array member, move its initialization earlier.
>
> [1]
> https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
>
> Cc: Dan Williams <[email protected]>
> Cc: Vishal Verma <[email protected]>
> Cc: Dave Jiang <[email protected]>
> Cc: Ira Weiny <[email protected]>
> Cc: [email protected]
> Signed-off-by: Kees Cook <[email protected]>
> ---
>  drivers/nvdimm/nd.h          | 2 +-
>  drivers/nvdimm/region_devs.c | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)

Reviewed-by: Vishal Verma <[email protected]>

>
> diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
> index e8b9d27dbb3c..ae2078eb6a62 100644
> --- a/drivers/nvdimm/nd.h
> +++ b/drivers/nvdimm/nd.h
> @@ -422,7 +422,7 @@ struct nd_region {
>         struct nd_interleave_set *nd_set;
>         struct nd_percpu_lane __percpu *lane;
>         int (*flush)(struct nd_region *nd_region, struct bio *bio);
> -       struct nd_mapping mapping[];
> +       struct nd_mapping mapping[] __counted_by(ndr_mappings);
>  };
>  
>  static inline bool nsl_validate_nlabel(struct nd_region *nd_region,
> diff --git a/drivers/nvdimm/region_devs.c
> b/drivers/nvdimm/region_devs.c
> index 0a81f87f6f6c..5be65fce85cf 100644
> --- a/drivers/nvdimm/region_devs.c
> +++ b/drivers/nvdimm/region_devs.c
> @@ -1028,6 +1028,7 @@ static struct nd_region
> *nd_region_create(struct nvdimm_bus *nvdimm_bus,
>  
>         if (!nd_region)
>                 return NULL;
> +       nd_region->ndr_mappings = ndr_desc->num_mappings;
>         /* CXL pre-assigns memregion ids before creating nvdimm
> regions */
>         if (test_bit(ND_REGION_CXL, &ndr_desc->flags)) {
>                 nd_region->id = ndr_desc->memregion;
> @@ -1062,7 +1063,6 @@ static struct nd_region
> *nd_region_create(struct nvdimm_bus *nvdimm_bus,
>  
>                 get_device(&nvdimm->dev);
>         }
> -       nd_region->ndr_mappings = ndr_desc->num_mappings;
>         nd_region->provider_data = ndr_desc->provider_data;
>         nd_region->nd_set = ndr_desc->nd_set;
>         nd_region->num_lanes = ndr_desc->num_lanes;


2023-09-22 23:55:41

by Dave Jiang

[permalink] [raw]
Subject: Re: [PATCH] libnvdimm: Annotate struct nd_region with __counted_by



On 9/22/23 10:52, 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 nd_region.
> Additionally, since the element count member must be set before accessing
> the annotated flexible array member, move its initialization earlier.
>
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
>
> Cc: Dan Williams <[email protected]>
> Cc: Vishal Verma <[email protected]>
> Cc: Dave Jiang <[email protected]>
> Cc: Ira Weiny <[email protected]>
> Cc: [email protected]
> Signed-off-by: Kees Cook <[email protected]>

Reviewed-by: Dave Jiang <[email protected]>

> ---
> drivers/nvdimm/nd.h | 2 +-
> drivers/nvdimm/region_devs.c | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
> index e8b9d27dbb3c..ae2078eb6a62 100644
> --- a/drivers/nvdimm/nd.h
> +++ b/drivers/nvdimm/nd.h
> @@ -422,7 +422,7 @@ struct nd_region {
> struct nd_interleave_set *nd_set;
> struct nd_percpu_lane __percpu *lane;
> int (*flush)(struct nd_region *nd_region, struct bio *bio);
> - struct nd_mapping mapping[];
> + struct nd_mapping mapping[] __counted_by(ndr_mappings);
> };
>
> static inline bool nsl_validate_nlabel(struct nd_region *nd_region,
> diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
> index 0a81f87f6f6c..5be65fce85cf 100644
> --- a/drivers/nvdimm/region_devs.c
> +++ b/drivers/nvdimm/region_devs.c
> @@ -1028,6 +1028,7 @@ static struct nd_region *nd_region_create(struct nvdimm_bus *nvdimm_bus,
>
> if (!nd_region)
> return NULL;
> + nd_region->ndr_mappings = ndr_desc->num_mappings;
> /* CXL pre-assigns memregion ids before creating nvdimm regions */
> if (test_bit(ND_REGION_CXL, &ndr_desc->flags)) {
> nd_region->id = ndr_desc->memregion;
> @@ -1062,7 +1063,6 @@ static struct nd_region *nd_region_create(struct nvdimm_bus *nvdimm_bus,
>
> get_device(&nvdimm->dev);
> }
> - nd_region->ndr_mappings = ndr_desc->num_mappings;
> nd_region->provider_data = ndr_desc->provider_data;
> nd_region->nd_set = ndr_desc->nd_set;
> nd_region->num_lanes = ndr_desc->num_lanes;

2023-09-23 09:04:04

by Gustavo A. R. Silva

[permalink] [raw]
Subject: Re: [PATCH] libnvdimm: Annotate struct nd_region with __counted_by

On Fri, Sep 22, 2023 at 10:52:39AM -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 nd_region.
> Additionally, since the element count member must be set before accessing
> the annotated flexible array member, move its initialization earlier.
>
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
>
> Cc: Dan Williams <[email protected]>
> Cc: Vishal Verma <[email protected]>
> Cc: Dave Jiang <[email protected]>
> Cc: Ira Weiny <[email protected]>
> Cc: [email protected]
> Signed-off-by: Kees Cook <[email protected]>

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

Thanks
--
Gustavo

> ---
> drivers/nvdimm/nd.h | 2 +-
> drivers/nvdimm/region_devs.c | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
> index e8b9d27dbb3c..ae2078eb6a62 100644
> --- a/drivers/nvdimm/nd.h
> +++ b/drivers/nvdimm/nd.h
> @@ -422,7 +422,7 @@ struct nd_region {
> struct nd_interleave_set *nd_set;
> struct nd_percpu_lane __percpu *lane;
> int (*flush)(struct nd_region *nd_region, struct bio *bio);
> - struct nd_mapping mapping[];
> + struct nd_mapping mapping[] __counted_by(ndr_mappings);
> };
>
> static inline bool nsl_validate_nlabel(struct nd_region *nd_region,
> diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
> index 0a81f87f6f6c..5be65fce85cf 100644
> --- a/drivers/nvdimm/region_devs.c
> +++ b/drivers/nvdimm/region_devs.c
> @@ -1028,6 +1028,7 @@ static struct nd_region *nd_region_create(struct nvdimm_bus *nvdimm_bus,
>
> if (!nd_region)
> return NULL;
> + nd_region->ndr_mappings = ndr_desc->num_mappings;
> /* CXL pre-assigns memregion ids before creating nvdimm regions */
> if (test_bit(ND_REGION_CXL, &ndr_desc->flags)) {
> nd_region->id = ndr_desc->memregion;
> @@ -1062,7 +1063,6 @@ static struct nd_region *nd_region_create(struct nvdimm_bus *nvdimm_bus,
>
> get_device(&nvdimm->dev);
> }
> - nd_region->ndr_mappings = ndr_desc->num_mappings;
> nd_region->provider_data = ndr_desc->provider_data;
> nd_region->nd_set = ndr_desc->nd_set;
> nd_region->num_lanes = ndr_desc->num_lanes;
> --
> 2.34.1
>
>