Re: [PATCH] drivers: of: check input parameter name for __of_find_property

[Peng Fan]

On Tue, Sep 15, 2015 at 09:27:59PM -0500, Rob Herring wrote:
> On 09/15/2015 07:16 PM, Peng Fan wrote:
> > Hi Rob,
> > 
> > On Tue, Sep 15, 2015 at 10:56:28AM -0500, Rob Herring wrote:
> >> On 09/11/2015 08:44 AM, Peng Fan wrote:
> >>> Check input parameter 'name' for __of_find_property. If name is NULL,
> >>> of_prop_cmp->strcasecmp may trigger panic.
> >>
> >> Arguably that could be a feature. Do you have a usecase where name being
> >> NULL is valid and panicking is a problem?
> > 
> > In drivers/pinctrl/devicetree.c
> > 
> > 195 propname = kasprintf(GFP_KERNEL, "pinctrl-%d", state);
> > 196 prop = of_find_property(np, propname, );
> > 197 kfree(propname);
> > 198 if (!prop)
> > 199 break;
> > 
> > If propname is NULL, of_find_property may trigger panic. Anyway propname 
> > should be checked
> > before passing to of_find_property.
> 
> propname will only be NULL if the memory allocation failed which gives
> you a big warning message. I don't think you would want to continue on
> in this case.
> 
> So I'm inclined to leave this as is with passing NULL to
> of_find_property to always be an error and fatal.

of_find_property has EXPORT_SYMBOL, it maybe called in different places. And it 
should handle the case that name is NULL, right?
If passing NULL to of_find_property is an error, then why check parameter 'np' 
like "if (!np)" in of_find_property?

Regards,
Peng.

> 
> Rob
> 
> > I did not met panic message. I wrote this patch when I was reading the 
> > piece code.
> > I think the name parameter should be checked before doing string compare.
> > 
> > Regards,
> > Peng.
> > 
> >>
> >> Rob
> >>
> >>>
> >>> Signed-off-by: Peng Fan 
> >>> Cc: Rob Herring 
> >>> Cc: Frank Rowand 
> >>> Cc: Grant Likely 
> >>> ---
> >>>  drivers/of/base.c | 2 +-
> >>>  1 file changed, 1 insertion(+), 1 deletion(-)
> >>>
> >>> diff --git a/drivers/of/base.c b/drivers/of/base.c
> >>> index 8b5a187..e41436d 100644
> >>> --- a/drivers/of/base.c
> >>> +++ b/drivers/of/base.c
> >>> @@ -215,7 +215,7 @@ static struct property *__of_find_property(const 
> >>> struct device_node *np,
> >>>  {
> >>>   struct property *pp;
> >>>  
> >>> - if (!np)
> >>> + if (!np || !name)
> >>>   return NULL;
> >>>  
> >>>   for (pp = np->properties; pp; pp = pp->next) {
> >>>
> >>
> 
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Re: [PATCH] drivers: of: check input parameter name for __of_find_property

[Peng Fan]

On Tue, Sep 15, 2015 at 09:27:59PM -0500, Rob Herring wrote:
> On 09/15/2015 07:16 PM, Peng Fan wrote:
> > Hi Rob,
> > 
> > On Tue, Sep 15, 2015 at 10:56:28AM -0500, Rob Herring wrote:
> >> On 09/11/2015 08:44 AM, Peng Fan wrote:
> >>> Check input parameter 'name' for __of_find_property. If name is NULL,
> >>> of_prop_cmp->strcasecmp may trigger panic.
> >>
> >> Arguably that could be a feature. Do you have a usecase where name being
> >> NULL is valid and panicking is a problem?
> > 
> > In drivers/pinctrl/devicetree.c
> > 
> > 195 propname = kasprintf(GFP_KERNEL, "pinctrl-%d", state);
> > 196 prop = of_find_property(np, propname, );
> > 197 kfree(propname);
> > 198 if (!prop)
> > 199 break;
> > 
> > If propname is NULL, of_find_property may trigger panic. Anyway propname 
> > should be checked
> > before passing to of_find_property.
> 
> propname will only be NULL if the memory allocation failed which gives
> you a big warning message. I don't think you would want to continue on
> in this case.
> 
> So I'm inclined to leave this as is with passing NULL to
> of_find_property to always be an error and fatal.

of_find_property has EXPORT_SYMBOL, it maybe called in different places. And it 
should handle the case that name is NULL, right?
If passing NULL to of_find_property is an error, then why check parameter 'np' 
like "if (!np)" in of_find_property?

Regards,
Peng.

> 
> Rob
> 
> > I did not met panic message. I wrote this patch when I was reading the 
> > piece code.
> > I think the name parameter should be checked before doing string compare.
> > 
> > Regards,
> > Peng.
> > 
> >>
> >> Rob
> >>
> >>>
> >>> Signed-off-by: Peng Fan 
> >>> Cc: Rob Herring 
> >>> Cc: Frank Rowand 
> >>> Cc: Grant Likely 
> >>> ---
> >>>  drivers/of/base.c | 2 +-
> >>>  1 file changed, 1 insertion(+), 1 deletion(-)
> >>>
> >>> diff --git a/drivers/of/base.c b/drivers/of/base.c
> >>> index 8b5a187..e41436d 100644
> >>> --- a/drivers/of/base.c
> >>> +++ b/drivers/of/base.c
> >>> @@ -215,7 +215,7 @@ static struct property *__of_find_property(const 
> >>> struct device_node *np,
> >>>  {
> >>>   struct property *pp;
> >>>  
> >>> - if (!np)
> >>> + if (!np || !name)
> >>>   return NULL;
> >>>  
> >>>   for (pp = np->properties; pp; pp = pp->next) {
> >>>
> >>
> 
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Re: [PATCH] drivers: of: check input parameter name for __of_find_property

[Rob Herring]

On 09/15/2015 07:16 PM, Peng Fan wrote:
> Hi Rob,
> 
> On Tue, Sep 15, 2015 at 10:56:28AM -0500, Rob Herring wrote:
>> On 09/11/2015 08:44 AM, Peng Fan wrote:
>>> Check input parameter 'name' for __of_find_property. If name is NULL,
>>> of_prop_cmp->strcasecmp may trigger panic.
>>
>> Arguably that could be a feature. Do you have a usecase where name being
>> NULL is valid and panicking is a problem?
> 
> In drivers/pinctrl/devicetree.c
> 
> 195 propname = kasprintf(GFP_KERNEL, "pinctrl-%d", state);
> 196 prop = of_find_property(np, propname, );
> 197 kfree(propname);
> 198 if (!prop)
> 199 break;
> 
> If propname is NULL, of_find_property may trigger panic. Anyway propname 
> should be checked
> before passing to of_find_property.

propname will only be NULL if the memory allocation failed which gives
you a big warning message. I don't think you would want to continue on
in this case.

So I'm inclined to leave this as is with passing NULL to
of_find_property to always be an error and fatal.

Rob

> I did not met panic message. I wrote this patch when I was reading the piece 
> code.
> I think the name parameter should be checked before doing string compare.
> 
> Regards,
> Peng.
> 
>>
>> Rob
>>
>>>
>>> Signed-off-by: Peng Fan 
>>> Cc: Rob Herring 
>>> Cc: Frank Rowand 
>>> Cc: Grant Likely 
>>> ---
>>>  drivers/of/base.c | 2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/of/base.c b/drivers/of/base.c
>>> index 8b5a187..e41436d 100644
>>> --- a/drivers/of/base.c
>>> +++ b/drivers/of/base.c
>>> @@ -215,7 +215,7 @@ static struct property *__of_find_property(const struct 
>>> device_node *np,
>>>  {
>>> struct property *pp;
>>>  
>>> -   if (!np)
>>> +   if (!np || !name)
>>> return NULL;
>>>  
>>> for (pp = np->properties; pp; pp = pp->next) {
>>>
>>

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Re: [PATCH] drivers: of: check input parameter name for __of_find_property

[Peng Fan]

Hi Rob,

On Tue, Sep 15, 2015 at 10:56:28AM -0500, Rob Herring wrote:
> On 09/11/2015 08:44 AM, Peng Fan wrote:
> > Check input parameter 'name' for __of_find_property. If name is NULL,
> > of_prop_cmp->strcasecmp may trigger panic.
> 
> Arguably that could be a feature. Do you have a usecase where name being
> NULL is valid and panicking is a problem?

In drivers/pinctrl/devicetree.c

195 propname = kasprintf(GFP_KERNEL, "pinctrl-%d", state);
196 prop = of_find_property(np, propname, );
197 kfree(propname);
198 if (!prop)
199 break;

If propname is NULL, of_find_property may trigger panic. Anyway propname should 
be checked
before passing to of_find_property.

I did not met panic message. I wrote this patch when I was reading the piece 
code.
I think the name parameter should be checked before doing string compare.

Regards,
Peng.

> 
> Rob
> 
> > 
> > Signed-off-by: Peng Fan 
> > Cc: Rob Herring 
> > Cc: Frank Rowand 
> > Cc: Grant Likely 
> > ---
> >  drivers/of/base.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/of/base.c b/drivers/of/base.c
> > index 8b5a187..e41436d 100644
> > --- a/drivers/of/base.c
> > +++ b/drivers/of/base.c
> > @@ -215,7 +215,7 @@ static struct property *__of_find_property(const struct 
> > device_node *np,
> >  {
> > struct property *pp;
> >  
> > -   if (!np)
> > +   if (!np || !name)
> > return NULL;
> >  
> > for (pp = np->properties; pp; pp = pp->next) {
> > 
> 
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Re: [PATCH] drivers: of: check input parameter name for __of_find_property

[Rob Herring]

On 09/11/2015 08:44 AM, Peng Fan wrote:
> Check input parameter 'name' for __of_find_property. If name is NULL,
> of_prop_cmp->strcasecmp may trigger panic.

Arguably that could be a feature. Do you have a usecase where name being
NULL is valid and panicking is a problem?

Rob

> 
> Signed-off-by: Peng Fan 
> Cc: Rob Herring 
> Cc: Frank Rowand 
> Cc: Grant Likely 
> ---
>  drivers/of/base.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/of/base.c b/drivers/of/base.c
> index 8b5a187..e41436d 100644
> --- a/drivers/of/base.c
> +++ b/drivers/of/base.c
> @@ -215,7 +215,7 @@ static struct property *__of_find_property(const struct 
> device_node *np,
>  {
>   struct property *pp;
>  
> - if (!np)
> + if (!np || !name)
>   return NULL;
>  
>   for (pp = np->properties; pp; pp = pp->next) {
> 

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Re: [PATCH] drivers: of: check input parameter name for __of_find_property

[Peng Fan]

Hi Rob,

On Tue, Sep 15, 2015 at 10:56:28AM -0500, Rob Herring wrote:
> On 09/11/2015 08:44 AM, Peng Fan wrote:
> > Check input parameter 'name' for __of_find_property. If name is NULL,
> > of_prop_cmp->strcasecmp may trigger panic.
> 
> Arguably that could be a feature. Do you have a usecase where name being
> NULL is valid and panicking is a problem?

In drivers/pinctrl/devicetree.c

195 propname = kasprintf(GFP_KERNEL, "pinctrl-%d", state);
196 prop = of_find_property(np, propname, );
197 kfree(propname);
198 if (!prop)
199 break;

If propname is NULL, of_find_property may trigger panic. Anyway propname should 
be checked
before passing to of_find_property.

I did not met panic message. I wrote this patch when I was reading the piece 
code.
I think the name parameter should be checked before doing string compare.

Regards,
Peng.

> 
> Rob
> 
> > 
> > Signed-off-by: Peng Fan 
> > Cc: Rob Herring 
> > Cc: Frank Rowand 
> > Cc: Grant Likely 
> > ---
> >  drivers/of/base.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/of/base.c b/drivers/of/base.c
> > index 8b5a187..e41436d 100644
> > --- a/drivers/of/base.c
> > +++ b/drivers/of/base.c
> > @@ -215,7 +215,7 @@ static struct property *__of_find_property(const struct 
> > device_node *np,
> >  {
> > struct property *pp;
> >  
> > -   if (!np)
> > +   if (!np || !name)
> > return NULL;
> >  
> > for (pp = np->properties; pp; pp = pp->next) {
> > 
> 
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Please read the FAQ at  http://www.tux.org/lkml/

Re: [PATCH] drivers: of: check input parameter name for __of_find_property

[Rob Herring]

On 09/15/2015 07:16 PM, Peng Fan wrote:
> Hi Rob,
> 
> On Tue, Sep 15, 2015 at 10:56:28AM -0500, Rob Herring wrote:
>> On 09/11/2015 08:44 AM, Peng Fan wrote:
>>> Check input parameter 'name' for __of_find_property. If name is NULL,
>>> of_prop_cmp->strcasecmp may trigger panic.
>>
>> Arguably that could be a feature. Do you have a usecase where name being
>> NULL is valid and panicking is a problem?
> 
> In drivers/pinctrl/devicetree.c
> 
> 195 propname = kasprintf(GFP_KERNEL, "pinctrl-%d", state);
> 196 prop = of_find_property(np, propname, );
> 197 kfree(propname);
> 198 if (!prop)
> 199 break;
> 
> If propname is NULL, of_find_property may trigger panic. Anyway propname 
> should be checked
> before passing to of_find_property.

propname will only be NULL if the memory allocation failed which gives
you a big warning message. I don't think you would want to continue on
in this case.

So I'm inclined to leave this as is with passing NULL to
of_find_property to always be an error and fatal.

Rob

> I did not met panic message. I wrote this patch when I was reading the piece 
> code.
> I think the name parameter should be checked before doing string compare.
> 
> Regards,
> Peng.
> 
>>
>> Rob
>>
>>>
>>> Signed-off-by: Peng Fan 
>>> Cc: Rob Herring 
>>> Cc: Frank Rowand 
>>> Cc: Grant Likely 
>>> ---
>>>  drivers/of/base.c | 2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/of/base.c b/drivers/of/base.c
>>> index 8b5a187..e41436d 100644
>>> --- a/drivers/of/base.c
>>> +++ b/drivers/of/base.c
>>> @@ -215,7 +215,7 @@ static struct property *__of_find_property(const struct 
>>> device_node *np,
>>>  {
>>> struct property *pp;
>>>  
>>> -   if (!np)
>>> +   if (!np || !name)
>>> return NULL;
>>>  
>>> for (pp = np->properties; pp; pp = pp->next) {
>>>
>>

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Re: [PATCH] drivers: of: check input parameter name for __of_find_property

[Rob Herring]

On 09/11/2015 08:44 AM, Peng Fan wrote:
> Check input parameter 'name' for __of_find_property. If name is NULL,
> of_prop_cmp->strcasecmp may trigger panic.

Arguably that could be a feature. Do you have a usecase where name being
NULL is valid and panicking is a problem?

Rob

> 
> Signed-off-by: Peng Fan 
> Cc: Rob Herring 
> Cc: Frank Rowand 
> Cc: Grant Likely 
> ---
>  drivers/of/base.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/of/base.c b/drivers/of/base.c
> index 8b5a187..e41436d 100644
> --- a/drivers/of/base.c
> +++ b/drivers/of/base.c
> @@ -215,7 +215,7 @@ static struct property *__of_find_property(const struct 
> device_node *np,
>  {
>   struct property *pp;
>  
> - if (!np)
> + if (!np || !name)
>   return NULL;
>  
>   for (pp = np->properties; pp; pp = pp->next) {
> 

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[PATCH] drivers: of: check input parameter name for __of_find_property

[Peng Fan]

Check input parameter 'name' for __of_find_property. If name is NULL,
of_prop_cmp->strcasecmp may trigger panic.

Signed-off-by: Peng Fan 
Cc: Rob Herring 
Cc: Frank Rowand 
Cc: Grant Likely 
---
 drivers/of/base.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index 8b5a187..e41436d 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -215,7 +215,7 @@ static struct property *__of_find_property(const struct 
device_node *np,
 {
struct property *pp;
 
-   if (!np)
+   if (!np || !name)
return NULL;
 
for (pp = np->properties; pp; pp = pp->next) {
-- 
1.8.4

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Please read the FAQ at  http://www.tux.org/lkml/

[PATCH] drivers: of: check input parameter name for __of_find_property

[Peng Fan]

Check input parameter 'name' for __of_find_property. If name is NULL,
of_prop_cmp->strcasecmp may trigger panic.

Signed-off-by: Peng Fan 
Cc: Rob Herring 
Cc: Frank Rowand 
Cc: Grant Likely 
---
 drivers/of/base.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index 8b5a187..e41436d 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -215,7 +215,7 @@ static struct property *__of_find_property(const struct 
device_node *np,
 {
struct property *pp;
 
-   if (!np)
+   if (!np || !name)
return NULL;
 
for (pp = np->properties; pp; pp = pp->next) {
-- 
1.8.4

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