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From: Harini Katakam <harini.katakam@xilinx.com>
To: <vkoul@kernel.org>, <romain.perier@gmail.com>,
	<allen.lkml@gmail.com>, <yukuai3@huawei.com>
Cc: <dmaengine@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>, <harinikatakamlinux@gmail.com>,
	<michal.simek@xilinx.com>, <harini.katakam@xilinx.com>,
	<radhey.shyam.pandey@xilinx.com>, <shravya.kumbham@xilinx.com>
Subject: [PATCH 1/4] dmaengine: zynqmp_dma: Typecast the variable to handle overflow
Date: Tue, 14 Sep 2021 13:58:14 +0530	[thread overview]
Message-ID: <20210914082817.22311-2-harini.katakam@xilinx.com> (raw)
In-Reply-To: <20210914082817.22311-1-harini.katakam@xilinx.com>

From: Shravya Kumbham <shravya.kumbham@xilinx.com>

In zynqmp_dma_alloc/free_chan_resources functions there is a
potential overflow in the below expressions.

dma_alloc_coherent(chan->dev, (2 * chan->desc_size *
		   ZYNQMP_DMA_NUM_DESCS),
		   &chan->desc_pool_p, GFP_KERNEL);

dma_free_coherent(chan->dev,(2 * ZYNQMP_DMA_DESC_SIZE(chan) *
                 ZYNQMP_DMA_NUM_DESCS),
                chan->desc_pool_v, chan->desc_pool_p);

The arguments desc_size and ZYNQMP_DMA_NUM_DESCS are 32 bit. Though
this overflow condition is not observed but it is a potential problem
in the case of 32-bit multiplication. Hence fix it by using typecast.

Addresses-Coverity: Event overflow_before_widen.
Signed-off-by: Shravya Kumbham <shravya.kumbham@xilinx.com>
Reviewed-by: Radhey Shyam Pandey <radhey.shyam.pandey@xilinx.com>
---
 drivers/dma/xilinx/zynqmp_dma.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/xilinx/zynqmp_dma.c b/drivers/dma/xilinx/zynqmp_dma.c
index 5fecf5aa6e85..2d0eba25739d 100644
--- a/drivers/dma/xilinx/zynqmp_dma.c
+++ b/drivers/dma/xilinx/zynqmp_dma.c
@@ -490,7 +490,8 @@ static int zynqmp_dma_alloc_chan_resources(struct dma_chan *dchan)
 	}
 
 	chan->desc_pool_v = dma_alloc_coherent(chan->dev,
-					       (2 * chan->desc_size * ZYNQMP_DMA_NUM_DESCS),
+					       ((size_t)(2 * chan->desc_size) *
+						ZYNQMP_DMA_NUM_DESCS),
 					       &chan->desc_pool_p, GFP_KERNEL);
 	if (!chan->desc_pool_v)
 		return -ENOMEM;
@@ -677,7 +678,8 @@ static void zynqmp_dma_free_chan_resources(struct dma_chan *dchan)
 	zynqmp_dma_free_descriptors(chan);
 	spin_unlock_irqrestore(&chan->lock, irqflags);
 	dma_free_coherent(chan->dev,
-		(2 * ZYNQMP_DMA_DESC_SIZE(chan) * ZYNQMP_DMA_NUM_DESCS),
+		((size_t)(2 * ZYNQMP_DMA_DESC_SIZE(chan)) *
+		 ZYNQMP_DMA_NUM_DESCS),
 		chan->desc_pool_v, chan->desc_pool_p);
 	kfree(chan->sw_desc_pool);
 	pm_runtime_mark_last_busy(chan->dev);
-- 
2.17.1


  reply	other threads:[~2021-09-14  8:28 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-14  8:28 [PATCH 0/4] ZynqMP DMA fixes Harini Katakam
2021-09-14  8:28 ` Harini Katakam [this message]
2021-09-23 14:11   ` [PATCH 1/4] dmaengine: zynqmp_dma: Typecast the variable to handle overflow Michael Tretter
2021-10-25  6:10   ` Vinod Koul
2021-09-14  8:28 ` [PATCH 2/4] dmaengine: zynqmp_dma: Typecast the variable with dma_addr_t " Harini Katakam
2021-09-14  8:28 ` [PATCH 3/4] dmaengine: zynqmp_dma: Add conditions for return value check Harini Katakam
2021-09-23 14:40   ` Michael Tretter
2021-10-25  6:12   ` Vinod Koul
2021-09-14  8:28 ` [PATCH 4/4] dmaengine: zynqmp_dma: Typecast with enum to fix the coverity warning Harini Katakam
2021-09-23 14:17   ` Michael Tretter

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