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@xxxxxxxxxx> Cc: Maxime Coquelin <mcoquelin.stm32@xxxxxxxxx> Cc: Alexandre Torgue <alexandre.torgue@xxxxxxxxxxx> Cc: dmaengine@xxxxxxxxxxxxxxx Cc: linux-stm32@xxxxxxxxxxxxxxxxxxxxxxxxxxxx Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> --- drivers/dma/stm32-mdma.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/dma/stm32-mdma.c b/drivers/dma/stm32-mdma.c index 926d6ecf1274..0c7d2295856e 100644 --- a/drivers/dma/stm32-mdma.c +++ b/drivers/dma/stm32-mdma.c @@ -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)) -- 2.34.1
