[PATCH] Add checks for kmalloc allocation failures

[PATCH] Add checks for kmalloc allocation failures

[Colin King]

From: Colin Ian King <colin.king@canonical.com>

Ensure we don't end up with a null pointer dereferences by checking
for for allocation failures.  Allocate by sizeof(*ptr) rather than
the type to fix checkpack warnings.  Also merge multiple lines into
one line for the kmalloc call.

Detected by CoverityScan, CID#1422435 ("Dereference null return value")

Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/net/ieee802154/ca8210.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/drivers/net/ieee802154/ca8210.c b/drivers/net/ieee802154/ca8210.c
index 53fa87bfede0..25fd3b04b3c0 100644
--- a/drivers/net/ieee802154/ca8210.c
+++ b/drivers/net/ieee802154/ca8210.c
@@ -634,6 +634,8 @@ static int ca8210_test_int_driver_write(
 		dev_dbg(&priv->spi->dev, "%#03x\n", buf[i]);
 
 	fifo_buffer = kmalloc(len, GFP_KERNEL);
+	if (!fifo_buffer)
+		return -ENOMEM;
 	memcpy(fifo_buffer, buf, len);
 	kfifo_in(&test->up_fifo, &fifo_buffer, 4);
 	wake_up_interruptible(&priv->test.readq);
@@ -759,10 +761,10 @@ static void ca8210_rx_done(struct cas_control *cas_ctl)
 				&priv->spi->dev,
 				"Resetting MAC...\n");
 
-			mlme_reset_wpc = kmalloc(
-				sizeof(struct work_priv_container),
-				GFP_KERNEL
-			);
+			mlme_reset_wpc = kmalloc(sizeof(*mlme_reset_wpc),
+						 GFP_KERNEL);
+			if (!mlme_reset_wpc)
+				goto finish;
 			INIT_WORK(
 				&mlme_reset_wpc->work,
 				ca8210_mlme_reset_worker
@@ -925,10 +927,10 @@ static int ca8210_spi_transfer(
 
 	dev_dbg(&spi->dev, "ca8210_spi_transfer called\n");
 
-	cas_ctl = kmalloc(
-		sizeof(struct cas_control),
-		GFP_ATOMIC
-	);
+	cas_ctl = kmalloc(sizeof(*cas_ctl), GFP_ATOMIC);
+	if (!cas_ctl)
+		return -ENOMEM;
+
 	cas_ctl->priv = priv;
 	memset(cas_ctl->tx_buf, SPI_IDLE, CA8210_SPI_BUF_SIZE);
 	memset(cas_ctl->tx_in_buf, SPI_IDLE, CA8210_SPI_BUF_SIZE);
-- 
2.11.0

Re: [PATCH] Add checks for kmalloc allocation failures

[Eric Dumazet]

On Wed, 2017-03-29 at 16:54 +0100, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
> 
> Ensure we don't end up with a null pointer dereferences by checking
> for for allocation failures.  Allocate by sizeof(*ptr) rather than
> the type to fix checkpack warnings.  Also merge multiple lines into
> one line for the kmalloc call.
> 
> Detected by CoverityScan, CID#1422435 ("Dereference null return value")

OK, but could you change patch title to be less generic ?

Also, what tree is this patch targeting ?

# ls -l drivers/net/ieee802154/ca8210.c 
ls: cannot access drivers/net/ieee802154/ca8210.c: No such file or
directory

Thanks.

Re: [PATCH] Add checks for kmalloc allocation failures

[walter harms]

Am 29.03.2017 17:54, schrieb Colin King:
> From: Colin Ian King <colin.king@canonical.com>
> 
> Ensure we don't end up with a null pointer dereferences by checking
> for for allocation failures.  Allocate by sizeof(*ptr) rather than
> the type to fix checkpack warnings.  Also merge multiple lines into
> one line for the kmalloc call.
> 
> Detected by CoverityScan, CID#1422435 ("Dereference null return value")
> 
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
>  drivers/net/ieee802154/ca8210.c | 18 ++++++++++--------
>  1 file changed, 10 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/net/ieee802154/ca8210.c b/drivers/net/ieee802154/ca8210.c
> index 53fa87bfede0..25fd3b04b3c0 100644
> --- a/drivers/net/ieee802154/ca8210.c
> +++ b/drivers/net/ieee802154/ca8210.c
> @@ -634,6 +634,8 @@ static int ca8210_test_int_driver_write(
>  		dev_dbg(&priv->spi->dev, "%#03x\n", buf[i]);
>  
>  	fifo_buffer = kmalloc(len, GFP_KERNEL);
> +	if (!fifo_buffer)
> +		return -ENOMEM;
>  	memcpy(fifo_buffer, buf, len);


perhaps kmemdup() ist the way to go ?
by replace kamlloc()+memcpy

re,
 wh

>  	kfifo_in(&test->up_fifo, &fifo_buffer, 4);
>  	wake_up_interruptible(&priv->test.readq);
> @@ -759,10 +761,10 @@ static void ca8210_rx_done(struct cas_control *cas_ctl)
>  				&priv->spi->dev,
>  				"Resetting MAC...\n");
>  
> -			mlme_reset_wpc = kmalloc(
> -				sizeof(struct work_priv_container),
> -				GFP_KERNEL
> -			);
> +			mlme_reset_wpc = kmalloc(sizeof(*mlme_reset_wpc),
> +						 GFP_KERNEL);
> +			if (!mlme_reset_wpc)
> +				goto finish;
>  			INIT_WORK(
>  				&mlme_reset_wpc->work,
>  				ca8210_mlme_reset_worker
> @@ -925,10 +927,10 @@ static int ca8210_spi_transfer(
>  
>  	dev_dbg(&spi->dev, "ca8210_spi_transfer called\n");
>  
> -	cas_ctl = kmalloc(
> -		sizeof(struct cas_control),
> -		GFP_ATOMIC
> -	);
> +	cas_ctl = kmalloc(sizeof(*cas_ctl), GFP_ATOMIC);
> +	if (!cas_ctl)
> +		return -ENOMEM;
> +
>  	cas_ctl->priv = priv;
>  	memset(cas_ctl->tx_buf, SPI_IDLE, CA8210_SPI_BUF_SIZE);
>  	memset(cas_ctl->tx_in_buf, SPI_IDLE, CA8210_SPI_BUF_SIZE);

Re: [PATCH] Add checks for kmalloc allocation failures

[Stefan Schmidt]

Hello.

On 03/29/2017 06:21 PM, Eric Dumazet wrote:
> On Wed, 2017-03-29 at 16:54 +0100, Colin King wrote:
>> From: Colin Ian King <colin.king@canonical.com>
>>
>> Ensure we don't end up with a null pointer dereferences by checking
>> for for allocation failures.  Allocate by sizeof(*ptr) rather than
>> the type to fix checkpack warnings.  Also merge multiple lines into
>> one line for the kmalloc call.
>>
>> Detected by CoverityScan, CID#1422435 ("Dereference null return value")
>
> OK, but could you change patch title to be less generic ?
>
> Also, what tree is this patch targeting ?
>
> # ls -l drivers/net/ieee802154/ca8210.c
> ls: cannot access drivers/net/ieee802154/ca8210.c: No such file or
> directory

This new driver is sitting in bluetooth-next right now for the next merge.

regards
Stefan Schmidt