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 <dan.j.willi...@intel.com> Cc: Vishal Verma <vishal.l.ve...@intel.com> Cc: Dave Jiang <dave.ji...@intel.com> Cc: Ira Weiny <ira.we...@intel.com> Cc: nvd...@lists.linux.dev Signed-off-by: Kees Cook <keesc...@chromium.org> --- 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
