[PATCH] i3c/master/mipi-i3c-hci: Annotate struct hci_rings_data 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 hci_rings_data.

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

Cc: Alexandre Belloni <alexandre.belloni at bootlin.com>
Cc: Nicolas Pitre <npitre at baylibre.com>
Cc: Len Baker <len.baker at gmx.com>
Cc: Boris Brezillon <boris.brezillon at collabora.com>
Cc: linux-i3c at lists.infradead.org
Signed-off-by: Kees Cook <keescook at chromium.org>
---
 drivers/i3c/master/mipi-i3c-hci/dma.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/i3c/master/mipi-i3c-hci/dma.c b/drivers/i3c/master/mipi-i3c-hci/dma.c
index 2990ac9eaade..a1ecdfc35641 100644
--- a/drivers/i3c/master/mipi-i3c-hci/dma.c
+++ b/drivers/i3c/master/mipi-i3c-hci/dma.c
@@ -139,7 +139,7 @@ struct hci_rh_data {
 
 struct hci_rings_data {
 	unsigned int total;
-	struct hci_rh_data headers[];
+	struct hci_rh_data headers[] __counted_by(total);
 };
 
 struct hci_dma_dev_ibi_data {
-- 
2.34.1