[PATCH v2] staging: vt6655: check for memory allocation failures

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* [PATCH v2] staging: vt6655: check for memory allocation failures
       [not found] <CGME20180329072248epcas2p3d12617d41e964252998dd1d34f740a97@epcas2p3.samsung.com>
@ 2018-03-29  7:22 ` Ji-Hun Kim
  2018-03-29  8:00   ` Jia-Ju Bai
  0 siblings, 1 reply; 3+ messages in thread
From: Ji-Hun Kim @ 2018-03-29  7:22 UTC (permalink / raw)
  To: gregkh, baijiaju1990, forest
  Cc: devel, y.k.oh, kernel-janitors, linux-kernel, julia.lawall,
	ji_hun.kim, santhameena13

There are no null pointer checking on rd_info and td_info values which
are allocated by kzalloc. It has potential null pointer dereferencing
issues. Add return when allocation is failed.

Signed-off-by: Ji-Hun Kim <ji_hun.kim@samsung.com>
---

Change: since v1:

- Delete WARN_ON which can makes crashes on some machines.
- Instead of return directly, goto freeing function for freeing previously
  allocated memory in the for loop after kzalloc() failed.
- In the freeing function, if td_info and rd_info are not allocated, no
  needs to free.

 drivers/staging/vt6655/device_main.c | 64 +++++++++++++++++++++++++-----------
 1 file changed, 44 insertions(+), 20 deletions(-)

diff --git a/drivers/staging/vt6655/device_main.c b/drivers/staging/vt6655/device_main.c
index fbc4bc6..ecbba43 100644
--- a/drivers/staging/vt6655/device_main.c
+++ b/drivers/staging/vt6655/device_main.c
@@ -539,7 +539,8 @@ static void device_init_rd0_ring(struct vnt_private *priv)
 	     i ++, curr += sizeof(struct vnt_rx_desc)) {
 		desc = &priv->aRD0Ring[i];
 		desc->rd_info = kzalloc(sizeof(*desc->rd_info), GFP_KERNEL);
-
+		if (!desc->rd_info)
+			goto error;
 		if (!device_alloc_rx_buf(priv, desc))
 			dev_err(&priv->pcid->dev, "can not alloc rx bufs\n");
 
@@ -550,6 +551,10 @@ static void device_init_rd0_ring(struct vnt_private *priv)
 	if (i > 0)
 		priv->aRD0Ring[i-1].next_desc = cpu_to_le32(priv->rd0_pool_dma);
 	priv->pCurrRD[0] = &priv->aRD0Ring[0];
+
+	return;
+error:
+	device_free_rd0_ring(priv);
 }
 
 static void device_init_rd1_ring(struct vnt_private *priv)
@@ -563,7 +568,8 @@ static void device_init_rd1_ring(struct vnt_private *priv)
 	     i ++, curr += sizeof(struct vnt_rx_desc)) {
 		desc = &priv->aRD1Ring[i];
 		desc->rd_info = kzalloc(sizeof(*desc->rd_info), GFP_KERNEL);
-
+		if (!desc->rd_info)
+			goto error;
 		if (!device_alloc_rx_buf(priv, desc))
 			dev_err(&priv->pcid->dev, "can not alloc rx bufs\n");
 
@@ -574,6 +580,10 @@ static void device_init_rd1_ring(struct vnt_private *priv)
 	if (i > 0)
 		priv->aRD1Ring[i-1].next_desc = cpu_to_le32(priv->rd1_pool_dma);
 	priv->pCurrRD[1] = &priv->aRD1Ring[0];
+
+	return;
+error:
+	device_free_rd1_ring(priv);
 }
 
 static void device_free_rd0_ring(struct vnt_private *priv)
@@ -584,12 +594,12 @@ static void device_free_rd0_ring(struct vnt_private *priv)
 		struct vnt_rx_desc *desc = &priv->aRD0Ring[i];
 		struct vnt_rd_info *rd_info = desc->rd_info;
 
-		dma_unmap_single(&priv->pcid->dev, rd_info->skb_dma,
-				 priv->rx_buf_sz, DMA_FROM_DEVICE);
-
-		dev_kfree_skb(rd_info->skb);
-
-		kfree(desc->rd_info);
+		if (rd_info) {
+			dma_unmap_single(&priv->pcid->dev, rd_info->skb_dma,
+					priv->rx_buf_sz, DMA_FROM_DEVICE);
+			dev_kfree_skb(rd_info->skb);
+			kfree(desc->rd_info);
+		}
 	}
 }
 
@@ -601,12 +611,12 @@ static void device_free_rd1_ring(struct vnt_private *priv)
 		struct vnt_rx_desc *desc = &priv->aRD1Ring[i];
 		struct vnt_rd_info *rd_info = desc->rd_info;
 
-		dma_unmap_single(&priv->pcid->dev, rd_info->skb_dma,
-				 priv->rx_buf_sz, DMA_FROM_DEVICE);
-
-		dev_kfree_skb(rd_info->skb);
-
-		kfree(desc->rd_info);
+		if (rd_info) {
+			dma_unmap_single(&priv->pcid->dev, rd_info->skb_dma,
+					priv->rx_buf_sz, DMA_FROM_DEVICE);
+			dev_kfree_skb(rd_info->skb);
+			kfree(desc->rd_info);
+		}
 	}
 }
 
@@ -621,7 +631,8 @@ static void device_init_td0_ring(struct vnt_private *priv)
 	     i++, curr += sizeof(struct vnt_tx_desc)) {
 		desc = &priv->apTD0Rings[i];
 		desc->td_info = kzalloc(sizeof(*desc->td_info), GFP_KERNEL);
-
+		if (!desc->td_info)
+			goto error;
 		desc->td_info->buf = priv->tx0_bufs + i * PKT_BUF_SZ;
 		desc->td_info->buf_dma = priv->tx_bufs_dma0 + i * PKT_BUF_SZ;
 
@@ -632,6 +643,10 @@ static void device_init_td0_ring(struct vnt_private *priv)
 	if (i > 0)
 		priv->apTD0Rings[i-1].next_desc = cpu_to_le32(priv->td0_pool_dma);
 	priv->apTailTD[0] = priv->apCurrTD[0] = &priv->apTD0Rings[0];
+
+	return;
+error:
+	device_free_td0_ring(priv);
 }
 
 static void device_init_td1_ring(struct vnt_private *priv)
@@ -646,7 +661,8 @@ static void device_init_td1_ring(struct vnt_private *priv)
 	     i++, curr += sizeof(struct vnt_tx_desc)) {
 		desc = &priv->apTD1Rings[i];
 		desc->td_info = kzalloc(sizeof(*desc->td_info), GFP_KERNEL);
-
+		if (!desc->td_info)
+			goto error;
 		desc->td_info->buf = priv->tx1_bufs + i * PKT_BUF_SZ;
 		desc->td_info->buf_dma = priv->tx_bufs_dma1 + i * PKT_BUF_SZ;
 
@@ -657,6 +673,10 @@ static void device_init_td1_ring(struct vnt_private *priv)
 	if (i > 0)
 		priv->apTD1Rings[i-1].next_desc = cpu_to_le32(priv->td1_pool_dma);
 	priv->apTailTD[1] = priv->apCurrTD[1] = &priv->apTD1Rings[0];
+
+	return;
+error:
+	device_free_td1_ring(priv);
 }
 
 static void device_free_td0_ring(struct vnt_private *priv)
@@ -667,8 +687,10 @@ static void device_free_td0_ring(struct vnt_private *priv)
 		struct vnt_tx_desc *desc = &priv->apTD0Rings[i];
 		struct vnt_td_info *td_info = desc->td_info;
 
-		dev_kfree_skb(td_info->skb);
-		kfree(desc->td_info);
+		if (td_info) {
+			dev_kfree_skb(td_info->skb);
+			kfree(desc->td_info);
+		}
 	}
 }
 
@@ -680,8 +702,10 @@ static void device_free_td1_ring(struct vnt_private *priv)
 		struct vnt_tx_desc *desc = &priv->apTD1Rings[i];
 		struct vnt_td_info *td_info = desc->td_info;
 
-		dev_kfree_skb(td_info->skb);
-		kfree(desc->td_info);
+		if (td_info) {
+			dev_kfree_skb(td_info->skb);
+			kfree(desc->td_info);
+		}
 	}
 }
 
-- 
1.9.1


^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: [PATCH v2] staging: vt6655: check for memory allocation failures
  2018-03-29  7:22 ` [PATCH v2] staging: vt6655: check for memory allocation failures Ji-Hun Kim
@ 2018-03-29  8:00   ` Jia-Ju Bai
  2018-03-29 10:53     ` ji-hun Kim
  0 siblings, 1 reply; 3+ messages in thread
From: Jia-Ju Bai @ 2018-03-29  8:00 UTC (permalink / raw)
  To: Ji-Hun Kim, gregkh, forest
  Cc: devel, y.k.oh, kernel-janitors, linux-kernel, julia.lawall,
	santhameena13



On 2018/3/29 15:22, Ji-Hun Kim wrote:
> There are no null pointer checking on rd_info and td_info values which
> are allocated by kzalloc. It has potential null pointer dereferencing
> issues. Add return when allocation is failed.
>
> Signed-off-by: Ji-Hun Kim <ji_hun.kim@samsung.com>
> ---
>
> Change: since v1:
>
> - Delete WARN_ON which can makes crashes on some machines.
> - Instead of return directly, goto freeing function for freeing previously
>    allocated memory in the for loop after kzalloc() failed.
> - In the freeing function, if td_info and rd_info are not allocated, no
>    needs to free.
>
>   drivers/staging/vt6655/device_main.c | 64 +++++++++++++++++++++++++-----------
>   1 file changed, 44 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/staging/vt6655/device_main.c b/drivers/staging/vt6655/device_main.c
> index fbc4bc6..ecbba43 100644
> --- a/drivers/staging/vt6655/device_main.c
> +++ b/drivers/staging/vt6655/device_main.c
> @@ -539,7 +539,8 @@ static void device_init_rd0_ring(struct vnt_private *priv)
>   	     i ++, curr += sizeof(struct vnt_rx_desc)) {
>   		desc = &priv->aRD0Ring[i];
>   		desc->rd_info = kzalloc(sizeof(*desc->rd_info), GFP_KERNEL);
> -
> +		if (!desc->rd_info)
> +			goto error;
>   		if (!device_alloc_rx_buf(priv, desc))
>   			dev_err(&priv->pcid->dev, "can not alloc rx bufs\n");
>   
> @@ -550,6 +551,10 @@ static void device_init_rd0_ring(struct vnt_private *priv)
>   	if (i > 0)
>   		priv->aRD0Ring[i-1].next_desc = cpu_to_le32(priv->rd0_pool_dma);
>   	priv->pCurrRD[0] = &priv->aRD0Ring[0];
> +
> +	return;
> +error:
> +	device_free_rd0_ring(priv);
>   }
>   

I think you should return an error number here, because 
device_init_rd0_ring() is called by vnt_start().
You should also implement error handling code in vnt_start(), and let 
vnt_start() returns an error number too.
The same for device_init_rd1_ring(), device_init_td0_ring() and 
device_init_td1_ring().


Best wishes,
Jia-Ju Bai

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH v2] staging: vt6655: check for memory allocation failures
  2018-03-29  8:00   ` Jia-Ju Bai
@ 2018-03-29 10:53     ` ji-hun Kim
  0 siblings, 0 replies; 3+ messages in thread
From: ji-hun Kim @ 2018-03-29 10:53 UTC (permalink / raw)
  To: Jia-Ju Bai
  Cc: devel, y.k.oh, gregkh, kernel-janitors, linux-kernel,
	julia.lawall, Ji-Hun Kim, forest, santhameena13

2018-03-29 17:00 GMT+09:00 Jia-Ju Bai <baijiaju1990@gmail.com>:
>
>
>
> On 2018/3/29 15:22, Ji-Hun Kim wrote:
>>
>> There are no null pointer checking on rd_info and td_info values which
>> are allocated by kzalloc. It has potential null pointer dereferencing
>> issues. Add return when allocation is failed.
>>
>> Signed-off-by: Ji-Hun Kim <ji_hun.kim@samsung.com>
>> ---
>>
>> Change: since v1:
>>
>> - Delete WARN_ON which can makes crashes on some machines.
>> - Instead of return directly, goto freeing function for freeing previously
>>    allocated memory in the for loop after kzalloc() failed.
>> - In the freeing function, if td_info and rd_info are not allocated, no
>>    needs to free.
>>
>>   drivers/staging/vt6655/device_main.c | 64 +++++++++++++++++++++++++-----------
>>   1 file changed, 44 insertions(+), 20 deletions(-)
>>
>> diff --git a/drivers/staging/vt6655/device_main.c b/drivers/staging/vt6655/device_main.c
>> index fbc4bc6..ecbba43 100644
>> --- a/drivers/staging/vt6655/device_main.c
>> +++ b/drivers/staging/vt6655/device_main.c
>> @@ -539,7 +539,8 @@ static void device_init_rd0_ring(struct vnt_private *priv)
>>              i ++, curr += sizeof(struct vnt_rx_desc)) {
>>                 desc = &priv->aRD0Ring[i];
>>                 desc->rd_info = kzalloc(sizeof(*desc->rd_info), GFP_KERNEL);
>> -
>> +               if (!desc->rd_info)
>> +                       goto error;
>>                 if (!device_alloc_rx_buf(priv, desc))
>>                         dev_err(&priv->pcid->dev, "can not alloc rx bufs\n");
>>   @@ -550,6 +551,10 @@ static void device_init_rd0_ring(struct vnt_private *priv)
>>         if (i > 0)
>>                 priv->aRD0Ring[i-1].next_desc = cpu_to_le32(priv->rd0_pool_dma);
>>         priv->pCurrRD[0] = &priv->aRD0Ring[0];
>> +
>> +       return;
>> +error:
>> +       device_free_rd0_ring(priv);
>>   }
>>
>
>
> I think you should return an error number here, because device_init_rd0_ring() is called by vnt_start().
> You should also implement error handling code in vnt_start(), and let vnt_start() returns an error number too.
> The same for device_init_rd1_ring(), device_init_td0_ring() and device_init_td1_ring().
>

Hi Jia-Ju, Thanks for the feedback. All right, those function looks
that needs returns
an error number. I will implement error handling code and send a patch
v3 tomorrow

Best regards,
Ji-Hun

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2018-03-29 10:53 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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     [not found] <CGME20180329072248epcas2p3d12617d41e964252998dd1d34f740a97@epcas2p3.samsung.com>
2018-03-29  7:22 ` [PATCH v2] staging: vt6655: check for memory allocation failures Ji-Hun Kim
2018-03-29  8:00   ` Jia-Ju Bai
2018-03-29 10:53     ` ji-hun Kim

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