[PATCH 21/21] dmaengine: usb-dmac: Annotate struct usb_dmac_desc with __counted_by

Kees Cook
2023-08-18T00:10:16Z

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 usb_dmac_desc.

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

Cc: Vinod Koul <vkoul@kernel.org>
Cc: Yu Kuai <yukuai3@huawei.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jordy Zomer <jordy@pwning.systems>
Cc: Jernej Skrabec <jernej.skrabec@gmail.com>
Cc: Tudor Ambarus <tudor.ambarus@linaro.org>
Cc: dmaengine@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
drivers/dma/sh/usb-dmac.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dma/sh/usb-dmac.c b/drivers/dma/sh/usb-dmac.c
index b14cf350b669..4cfcd23e3268 100644
--- a/drivers/dma/sh/usb-dmac.c
+++ b/drivers/dma/sh/usb-dmac.c
@@ -57,7 +57,7 @@ struct usb_dmac_desc {
u32 residue;
struct list_head node;
dma_cookie_t done_cookie;
- struct usb_dmac_sg sg[];
+ struct usb_dmac_sg sg[] __counted_by(sg_allocated_len);
};

#define to_usb_dmac_desc(vd) container_of(vd, struct usb_dmac_desc, vd)
--
2.34.1