[PATCH 11/21] dmaengine: st_fdma: Annotate struct st_fdma_desc 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 st_fdma_desc.

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

Cc: Vinod Koul <vkoul@xxxxxxxxxx>
Cc: Patrice Chotard <patrice.chotard@xxxxxxxxxxx>
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: dmaengine@xxxxxxxxxxxxxxx
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
 drivers/dma/st_fdma.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dma/st_fdma.h b/drivers/dma/st_fdma.h
index fa15b97a3bab..f296412e96b6 100644
--- a/drivers/dma/st_fdma.h
+++ b/drivers/dma/st_fdma.h
@@ -97,7 +97,7 @@ struct st_fdma_desc {
 	struct st_fdma_chan *fchan;
 	bool iscyclic;
 	unsigned int n_nodes;
-	struct st_fdma_sw_node node[];
+	struct st_fdma_sw_node node[] __counted_by(n_nodes);
 };
 
 enum st_fdma_type {
-- 
2.34.1