[PATCH] mailbox: zynqmp: Annotate struct zynqmp_ipi_pdata with __counted_by

[Kees Cook]

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 zynqmp_ipi_pdata.

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

Cc: Jassi Brar <jassisinghbrar@xxxxxxxxx>
Cc: Michal Simek <michal.simek@xxxxxxx>
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
 drivers/mailbox/zynqmp-ipi-mailbox.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mailbox/zynqmp-ipi-mailbox.c b/drivers/mailbox/zynqmp-ipi-mailbox.c
index e4fcac97dbfa..7fa533e80dd9 100644
--- a/drivers/mailbox/zynqmp-ipi-mailbox.c
+++ b/drivers/mailbox/zynqmp-ipi-mailbox.c
@@ -108,7 +108,7 @@ struct zynqmp_ipi_pdata {
 	unsigned int method;
 	u32 local_id;
 	int num_mboxes;
-	struct zynqmp_ipi_mbox ipi_mboxes[];
+	struct zynqmp_ipi_mbox ipi_mboxes[] __counted_by(num_mboxes);
 };
 
 static struct device_driver zynqmp_ipi_mbox_driver = {
-- 
2.34.1