Commit 7ba0035d authored by Kees Cook's avatar Kees Cook Committed by Vinod Koul
Browse files

dmaengine: stm32-mdma: Annotate struct stm32_mdma_device with __counted_by 

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 stm32_mdma_device.
Additionally, since the element count member must be set before accessing
the annotated flexible array member, move its initialization earlier.

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



Cc: Vinod Koul <vkoul@kernel.org>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@foss.st.com>
Cc: dmaengine@vger.kernel.org
Cc: linux-stm32@st-md-mailman.stormreply.com
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Reviewed-by: default avatar"Gustavo A. R. Silva" <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20230817235859.49846-14-keescook@chromium.org


Signed-off-by: default avatarVinod Koul <vkoul@kernel.org>
parent 03547217

drivers/dma/stm32-mdma.c

+2 −2
Original line number Diff line number Diff line
@@ -256,7 +256,7 @@ struct stm32_mdma_device { 
	u32 nr_ahb_addr_masks;

	u32 chan_reserved;

	struct stm32_mdma_chan chan[STM32_MDMA_MAX_CHANNELS];

	u32 ahb_addr_masks[];

	u32 ahb_addr_masks[] __counted_by(nr_ahb_addr_masks);

};



static struct stm32_mdma_device *stm32_mdma_get_dev(
@@ -1611,13 +1611,13 @@ static int stm32_mdma_probe(struct platform_device *pdev) 
			      GFP_KERNEL);

	if (!dmadev)

		return -ENOMEM;

	dmadev->nr_ahb_addr_masks = count;



	dmadev->nr_channels = nr_channels;

	dmadev->nr_requests = nr_requests;

	device_property_read_u32_array(&pdev->dev, "st,ahb-addr-masks",

				       dmadev->ahb_addr_masks,

				       count);

	dmadev->nr_ahb_addr_masks = count;



	dmadev->base = devm_platform_ioremap_resource(pdev, 0);

	if (IS_ERR(dmadev->base))