On Fri, 22 Sep 2023, 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 cxl_cxims_data.
Additionally, since the element count member must be set before accessing
the annotated flexible array member, move its initialization earlier.
Nice.
Reviewed-by: Davidlohr Bueso <[email protected]>
[1]
https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
Cc: Davidlohr Bueso <[email protected]>
Cc: Jonathan Cameron <[email protected]>
Cc: Dave Jiang <[email protected]>
Cc: Alison Schofield <[email protected]>
Cc: Vishal Verma <[email protected]>
Cc: Ira Weiny <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: [email protected]
Signed-off-by: Kees Cook <[email protected]>
---
drivers/cxl/acpi.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c
index d1c559879dcc..40d055560e52 100644
--- a/drivers/cxl/acpi.c
+++ b/drivers/cxl/acpi.c
@@ -14,7 +14,7 @@
struct cxl_cxims_data {
int nr_maps;
- u64 xormaps[];
+ u64 xormaps[] __counted_by(nr_maps);
};
/*
@@ -112,9 +112,9 @@ static int cxl_parse_cxims(union acpi_subtable_headers
*header, void *arg,
GFP_KERNEL);
if (!cximsd)
return -ENOMEM;
+ cximsd->nr_maps = nr_maps;
memcpy(cximsd->xormaps, cxims->xormap_list,
nr_maps * sizeof(*cximsd->xormaps));
- cximsd->nr_maps = nr_maps;
cxlrd->platform_data = cximsd;
return 0;
--
2.34.1
