[PATCH] wifi: mt76: Annotate struct mt76_rx_tid 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 mt76_rx_tid.

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

Cc: Felix Fietkau <nbd at nbd.name>
Cc: Lorenzo Bianconi <lorenzo at kernel.org>
Cc: Ryder Lee <ryder.lee at mediatek.com>
Cc: Shayne Chen <shayne.chen at mediatek.com>
Cc: Sean Wang <sean.wang at mediatek.com>
Cc: Kalle Valo <kvalo at kernel.org>
Cc: Matthias Brugger <matthias.bgg at gmail.com>
Cc: AngeloGioacchino Del Regno <angelogioacchino.delregno at collabora.com>
Cc: linux-wireless at vger.kernel.org
Cc: linux-arm-kernel at lists.infradead.org
Cc: linux-mediatek at lists.infradead.org
Signed-off-by: Kees Cook <keescook at chromium.org>
---
 drivers/net/wireless/mediatek/mt76/mt76.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt76.h b/drivers/net/wireless/mediatek/mt76/mt76.h
index e8757865a3d0..03ef617b1527 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76.h
+++ b/drivers/net/wireless/mediatek/mt76/mt76.h
@@ -376,7 +376,7 @@ struct mt76_rx_tid {
 
 	u8 started:1, stopped:1, timer_pending:1;
 
-	struct sk_buff *reorder_buf[];
+	struct sk_buff *reorder_buf[] __counted_by(size);
 };
 
 #define MT_TX_CB_DMA_DONE		BIT(0)
-- 
2.34.1