[PATCH] char: tmp: fix potential null pointer dereference

[PATCH] char: tmp: fix potential null pointer dereference

[Gustavo A. R. Silva]

NULL check at line 147: if (chip) {, implies chip might be NULL.
Function dev_get_drvdata() dereference pointer chip.
Move pointer priv assignment inside the IF block that checks
pointer chip.

Addresses-Coverity-ID: 1397646
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
---
 drivers/char/tpm/tpm_atmel.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/char/tpm/tpm_atmel.c b/drivers/char/tpm/tpm_atmel.c
index 0d322ab..0826efd 100644
--- a/drivers/char/tpm/tpm_atmel.c
+++ b/drivers/char/tpm/tpm_atmel.c
@@ -142,9 +142,10 @@ static struct platform_device *pdev;
 static void atml_plat_remove(void)
 {
 	struct tpm_chip *chip = dev_get_drvdata(&pdev->dev);
-	struct tpm_atmel_priv *priv = dev_get_drvdata(&chip->dev);
+	struct tpm_atmel_priv *priv;
 
 	if (chip) {
+		priv = dev_get_drvdata(&chip->dev);
 		tpm_chip_unregister(chip);
 		if (priv->have_region)
 			atmel_release_region(priv->base, priv->region_size);
-- 
2.5.0

Re: [PATCH] char: tmp: fix potential null pointer dereference

[Jarkko Sakkinen]

On Tue, May 30, 2017 at 04:51:23PM -0500, Gustavo A. R. Silva wrote:
> NULL check at line 147: if (chip) {, implies chip might be NULL.
> Function dev_get_drvdata() dereference pointer chip.
> Move pointer priv assignment inside the IF block that checks
> pointer chip.
> 
> Addresses-Coverity-ID: 1397646
> Signed-off-by: Gustavo A. R. Silva <garsilva-L1vi/lXTdts+Va1GwOuvDg@public.gmane.org>

It cannot be.

/Jarkko

> ---
>  drivers/char/tpm/tpm_atmel.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/char/tpm/tpm_atmel.c b/drivers/char/tpm/tpm_atmel.c
> index 0d322ab..0826efd 100644
> --- a/drivers/char/tpm/tpm_atmel.c
> +++ b/drivers/char/tpm/tpm_atmel.c
> @@ -142,9 +142,10 @@ static struct platform_device *pdev;
>  static void atml_plat_remove(void)
>  {
>  	struct tpm_chip *chip = dev_get_drvdata(&pdev->dev);
> -	struct tpm_atmel_priv *priv = dev_get_drvdata(&chip->dev);
> +	struct tpm_atmel_priv *priv;
>  
>  	if (chip) {
> +		priv = dev_get_drvdata(&chip->dev);
>  		tpm_chip_unregister(chip);
>  		if (priv->have_region)
>  			atmel_release_region(priv->base, priv->region_size);
> -- 
> 2.5.0
> 

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Re: [PATCH] char: tmp: fix potential null pointer dereference

[Gustavo A. R. Silva]

Hi Jarkko,

Please, see my comments below

Quoting Jarkko Sakkinen <jarkko.sakkinen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>:

> On Tue, May 30, 2017 at 04:51:23PM -0500, Gustavo A. R. Silva wrote:
>> NULL check at line 147: if (chip) {, implies chip might be NULL.
>> Function dev_get_drvdata() dereference pointer chip.
>> Move pointer priv assignment inside the IF block that checks
>> pointer chip.
>>
>> Addresses-Coverity-ID: 1397646
>> Signed-off-by: Gustavo A. R. Silva <garsilva-L1vi/lXTdts+Va1GwOuvDg@public.gmane.org>
>
> It cannot be.
>

I got it.

> /Jarkko
>
>> ---
>>  drivers/char/tpm/tpm_atmel.c | 3 ++-
>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/char/tpm/tpm_atmel.c b/drivers/char/tpm/tpm_atmel.c
>> index 0d322ab..0826efd 100644
>> --- a/drivers/char/tpm/tpm_atmel.c
>> +++ b/drivers/char/tpm/tpm_atmel.c
>> @@ -142,9 +142,10 @@ static struct platform_device *pdev;
>>  static void atml_plat_remove(void)
>>  {
>>  	struct tpm_chip *chip = dev_get_drvdata(&pdev->dev);
>> -	struct tpm_atmel_priv *priv = dev_get_drvdata(&chip->dev);
>> +	struct tpm_atmel_priv *priv;
>>
>>  	if (chip) {

So, this NULL check could be removed?

>> +		priv = dev_get_drvdata(&chip->dev);
>>  		tpm_chip_unregister(chip);
>>  		if (priv->have_region)
>>  			atmel_release_region(priv->base, priv->region_size);
>> --
>> 2.5.0
>>

Thank you
--
Gustavo A. R. Silva





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Re: [PATCH] char: tmp: fix potential null pointer dereference

[Jarkko Sakkinen]

On Mon, Jun 12, 2017 at 05:25:44PM -0500, Gustavo A. R. Silva wrote:
> Hi Jarkko,
> 
> Please, see my comments below
> 
> Quoting Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>:
> 
> > On Tue, May 30, 2017 at 04:51:23PM -0500, Gustavo A. R. Silva wrote:
> > > NULL check at line 147: if (chip) {, implies chip might be NULL.
> > > Function dev_get_drvdata() dereference pointer chip.
> > > Move pointer priv assignment inside the IF block that checks
> > > pointer chip.
> > > 
> > > Addresses-Coverity-ID: 1397646
> > > Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
> > 
> > It cannot be.
> > 
> 
> I got it.
> 
> > /Jarkko
> > 
> > > ---
> > >  drivers/char/tpm/tpm_atmel.c | 3 ++-
> > >  1 file changed, 2 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/char/tpm/tpm_atmel.c b/drivers/char/tpm/tpm_atmel.c
> > > index 0d322ab..0826efd 100644
> > > --- a/drivers/char/tpm/tpm_atmel.c
> > > +++ b/drivers/char/tpm/tpm_atmel.c
> > > @@ -142,9 +142,10 @@ static struct platform_device *pdev;
> > >  static void atml_plat_remove(void)
> > >  {
> > >  	struct tpm_chip *chip = dev_get_drvdata(&pdev->dev);
> > > -	struct tpm_atmel_priv *priv = dev_get_drvdata(&chip->dev);
> > > +	struct tpm_atmel_priv *priv;
> > > 
> > >  	if (chip) {
> 
> So, this NULL check could be removed?

Yes, this would be right way to fix it.

/Jarkko

[PATCH] char: tpm: remove unnecessary NULL check

[Gustavo A. R. Silva]

Remove unnecessary NULL check.
Pointer _chip_ cannot be NULL in this instance.

Addresses-Coverity-ID: 1397646
Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
---
 drivers/char/tpm/tpm_atmel.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/drivers/char/tpm/tpm_atmel.c b/drivers/char/tpm/tpm_atmel.c
index 0d322ab..66a1452 100644
--- a/drivers/char/tpm/tpm_atmel.c
+++ b/drivers/char/tpm/tpm_atmel.c
@@ -144,13 +144,11 @@ static void atml_plat_remove(void)
 	struct tpm_chip *chip = dev_get_drvdata(&pdev->dev);
 	struct tpm_atmel_priv *priv = dev_get_drvdata(&chip->dev);
 
-	if (chip) {
-		tpm_chip_unregister(chip);
-		if (priv->have_region)
-			atmel_release_region(priv->base, priv->region_size);
-		atmel_put_base_addr(priv->iobase);
-		platform_device_unregister(pdev);
-	}
+	tpm_chip_unregister(chip);
+	if (priv->have_region)
+		atmel_release_region(priv->base, priv->region_size);
+	atmel_put_base_addr(priv->iobase);
+	platform_device_unregister(pdev);
 }
 
 static SIMPLE_DEV_PM_OPS(tpm_atml_pm, tpm_pm_suspend, tpm_pm_resume);
-- 
2.5.0

Re: [PATCH] char: tpm: remove unnecessary NULL check

[Jarkko Sakkinen]

On Tue, Jun 13, 2017 at 02:55:42PM -0500, Gustavo A. R. Silva wrote:
> Remove unnecessary NULL check.
> Pointer _chip_ cannot be NULL in this instance.
> 
> Addresses-Coverity-ID: 1397646
> Cc: Jarkko Sakkinen <jarkko.sakkinen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
> Signed-off-by: Gustavo A. R. Silva <garsilva-L1vi/lXTdts+Va1GwOuvDg@public.gmane.org>
> ---
>  drivers/char/tpm/tpm_atmel.c | 12 +++++-------
>  1 file changed, 5 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm_atmel.c b/drivers/char/tpm/tpm_atmel.c
> index 0d322ab..66a1452 100644
> --- a/drivers/char/tpm/tpm_atmel.c
> +++ b/drivers/char/tpm/tpm_atmel.c
> @@ -144,13 +144,11 @@ static void atml_plat_remove(void)
>  	struct tpm_chip *chip = dev_get_drvdata(&pdev->dev);
>  	struct tpm_atmel_priv *priv = dev_get_drvdata(&chip->dev);
>  
> -	if (chip) {
> -		tpm_chip_unregister(chip);
> -		if (priv->have_region)
> -			atmel_release_region(priv->base, priv->region_size);
> -		atmel_put_base_addr(priv->iobase);
> -		platform_device_unregister(pdev);
> -	}
> +	tpm_chip_unregister(chip);
> +	if (priv->have_region)
> +		atmel_release_region(priv->base, priv->region_size);
> +	atmel_put_base_addr(priv->iobase);
> +	platform_device_unregister(pdev);
>  }
>  
>  static SIMPLE_DEV_PM_OPS(tpm_atml_pm, tpm_pm_suspend, tpm_pm_resume);
> -- 
> 2.5.0
> 

Thank you.

Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>

/Jarkko

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Re: [PATCH] char: tpm: remove unnecessary NULL check

[Jarkko Sakkinen]

On Tue, 2017-06-13 at 14:55 -0500, Gustavo A. R. Silva wrote:
> Remove unnecessary NULL check.
> Pointer _chip_ cannot be NULL in this instance.
> 
> Addresses-Coverity-ID: 1397646
> Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>

Reviewed-by: Jarkko Sakkinen <jarkko.sakkine@linux.intel.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkine@linux.intel.com>
(compilation)

/Jarkko