[PATCH][next] dmaengine: at_xdmac: Use struct_size() in devm_kzalloc()

[PATCH][next] dmaengine: at_xdmac: Use struct_size() in devm_kzalloc()

[Gustavo A. R. Silva]

Make use of the struct_size() helper instead of an open-coded version, in
order to avoid any potential type mistakes or integer overflows that, in
the worst scenario, could lead to heap overflows.

Link: https://github.com/KSPP/linux/issues/160
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
 drivers/dma/at_xdmac.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c
index 275a76f188ae..e42dede5b243 100644
--- a/drivers/dma/at_xdmac.c
+++ b/drivers/dma/at_xdmac.c
@@ -2031,7 +2031,7 @@ static int __maybe_unused atmel_xdmac_resume(struct device *dev)
 static int at_xdmac_probe(struct platform_device *pdev)
 {
 	struct at_xdmac	*atxdmac;
-	int		irq, size, nr_channels, i, ret;
+	int		irq, nr_channels, i, ret;
 	void __iomem	*base;
 	u32		reg;
 
@@ -2056,9 +2056,9 @@ static int at_xdmac_probe(struct platform_device *pdev)
 		return -EINVAL;
 	}
 
-	size = sizeof(*atxdmac);
-	size += nr_channels * sizeof(struct at_xdmac_chan);
-	atxdmac = devm_kzalloc(&pdev->dev, size, GFP_KERNEL);
+	atxdmac = devm_kzalloc(&pdev->dev,
+			       struct_size(atxdmac, chan, nr_channels),
+			       GFP_KERNEL);
 	if (!atxdmac) {
 		dev_err(&pdev->dev, "can't allocate at_xdmac structure\n");
 		return -ENOMEM;
-- 
2.27.0

Re: [PATCH][next] dmaengine: at_xdmac: Use struct_size() in devm_kzalloc()

[Kees Cook]

On Tue, Dec 07, 2021 at 06:10:13PM -0600, Gustavo A. R. Silva wrote:
> Make use of the struct_size() helper instead of an open-coded version, in
> order to avoid any potential type mistakes or integer overflows that, in
> the worst scenario, could lead to heap overflows.
> 
> Link: https://github.com/KSPP/linux/issues/160
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook

Re: [PATCH][next] dmaengine: at_xdmac: Use struct_size() in devm_kzalloc()

[Vinod Koul]

On 07-12-21, 18:10, Gustavo A. R. Silva wrote:
> Make use of the struct_size() helper instead of an open-coded version, in
> order to avoid any potential type mistakes or integer overflows that, in
> the worst scenario, could lead to heap overflows.

Applied, thanks

-- 
~Vinod