diff mbox

[v2] coccinelle: api: check for propagation of error from platform_get_irq

Message ID alpine.DEB.2.02.1512262156580.2070@localhost6.localdomain6 (mailing list archive)
State New, archived
Headers show

Commit Message

Julia Lawall Dec. 26, 2015, 8:58 p.m. UTC
The error return value of platform_get_irq seems to often get dropped.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>

---

v2: Check for the direct return case also.  Added some mailing lists of
common offenders.

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Comments

Sergei Shtylyov Dec. 26, 2015, 10:26 p.m. UTC | #1
On 12/26/2015 11:58 PM, Julia Lawall wrote:

> The error return value of platform_get_irq seems to often get dropped.
>
> Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
>
> ---
>
> v2: Check for the direct return case also.  Added some mailing lists of
> common offenders.
>
> diff --git a/scripts/coccinelle/api/platform_get_irq_return.cocci b/scripts/coccinelle/api/platform_get_irq_return.cocci
> new file mode 100644
> index 0000000..44680d0
> --- /dev/null
> +++ b/scripts/coccinelle/api/platform_get_irq_return.cocci
> @@ -0,0 +1,58 @@
> +/// Propagate the return value of platform_get_irq.
> +//# Sometimes the return value of platform_get_irq is tested using <= 0, but 0
> +//# might not be an appropriate return value in an error case.
> +///
> +// Confidence: Moderate
> +// Copyright: (C) 2015 Julia Lawall, Inria. GPLv2.
> +// URL: http://coccinelle.lip6.fr/
> +// Options: --no-includes --include-headers
> +
> +virtual context
> +virtual org
> +virtual report
> +
> +// ----------------------------------------------------------------------------
> +
> +@r depends on context || org || report@
> +constant C;
> +statement S;
> +expression e, ret;
> +position j0, j1;
> +@@
> +
> +* e@j0 = platform_get_irq(...);
> +(
> +if@j1 (...) {
> +  ...
> +  return -C;
> +} else S
> +|
> +if@j1 (...) {
> +  ...
> +  ret = -C;
> +  ...
> +  return ret;
> +} else S

    Well, this seems to also cover the (e <= 0) checks which do make same 
sense in the light of Linus considering IRQ0 invalid. So I'd be more specific 
about the checks here -- 0 should indeed be overridden with something if it's 
considered invalid.

MBR, Sergei

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Julia Lawall Dec. 26, 2015, 10:32 p.m. UTC | #2
On Sun, 27 Dec 2015, Sergei Shtylyov wrote:

> On 12/26/2015 11:58 PM, Julia Lawall wrote:
> 
> > The error return value of platform_get_irq seems to often get dropped.
> > 
> > Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
> > 
> > ---
> > 
> > v2: Check for the direct return case also.  Added some mailing lists of
> > common offenders.
> > 
> > diff --git a/scripts/coccinelle/api/platform_get_irq_return.cocci
> > b/scripts/coccinelle/api/platform_get_irq_return.cocci
> > new file mode 100644
> > index 0000000..44680d0
> > --- /dev/null
> > +++ b/scripts/coccinelle/api/platform_get_irq_return.cocci
> > @@ -0,0 +1,58 @@
> > +/// Propagate the return value of platform_get_irq.
> > +//# Sometimes the return value of platform_get_irq is tested using <= 0,
> > but 0
> > +//# might not be an appropriate return value in an error case.
> > +///
> > +// Confidence: Moderate
> > +// Copyright: (C) 2015 Julia Lawall, Inria. GPLv2.
> > +// URL: http://coccinelle.lip6.fr/
> > +// Options: --no-includes --include-headers
> > +
> > +virtual context
> > +virtual org
> > +virtual report
> > +
> > +//
> > ----------------------------------------------------------------------------
> > +
> > +@r depends on context || org || report@
> > +constant C;
> > +statement S;
> > +expression e, ret;
> > +position j0, j1;
> > +@@
> > +
> > +* e@j0 = platform_get_irq(...);
> > +(
> > +if@j1 (...) {
> > +  ...
> > +  return -C;
> > +} else S
> > +|
> > +if@j1 (...) {
> > +  ...
> > +  ret = -C;
> > +  ...
> > +  return ret;
> > +} else S
> 
>    Well, this seems to also cover the (e <= 0) checks which do make same sense
> in the light of Linus considering IRQ0 invalid. So I'd be more specific about
> the checks here -- 0 should indeed be overridden with something if it's
> considered invalid.

That's what the limitations section says (lines with #).  This doesn't 
make any changes, it only makes warnings, which should include the 
limitations information, so perhaps people can consider what it is that 
they really intend to do.

If you think this is not a good idea, then I can make the test more 
specific.

julia
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Sergei Shtylyov Dec. 26, 2015, 10:36 p.m. UTC | #3
On 12/27/2015 01:32 AM, Julia Lawall wrote:

>>> The error return value of platform_get_irq seems to often get dropped.
>>>
>>> Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
>>>
>>> ---
>>>
>>> v2: Check for the direct return case also.  Added some mailing lists of
>>> common offenders.
>>>
>>> diff --git a/scripts/coccinelle/api/platform_get_irq_return.cocci
>>> b/scripts/coccinelle/api/platform_get_irq_return.cocci
>>> new file mode 100644
>>> index 0000000..44680d0
>>> --- /dev/null
>>> +++ b/scripts/coccinelle/api/platform_get_irq_return.cocci
>>> @@ -0,0 +1,58 @@
>>> +/// Propagate the return value of platform_get_irq.
>>> +//# Sometimes the return value of platform_get_irq is tested using <= 0,
>>> but 0
>>> +//# might not be an appropriate return value in an error case.
>>> +///
>>> +// Confidence: Moderate
>>> +// Copyright: (C) 2015 Julia Lawall, Inria. GPLv2.
>>> +// URL: http://coccinelle.lip6.fr/
>>> +// Options: --no-includes --include-headers
>>> +
>>> +virtual context
>>> +virtual org
>>> +virtual report
>>> +
>>> +//
>>> ----------------------------------------------------------------------------
>>> +
>>> +@r depends on context || org || report@
>>> +constant C;
>>> +statement S;
>>> +expression e, ret;
>>> +position j0, j1;
>>> +@@
>>> +
>>> +* e@j0 = platform_get_irq(...);
>>> +(
>>> +if@j1 (...) {
>>> +  ...
>>> +  return -C;
>>> +} else S
>>> +|
>>> +if@j1 (...) {
>>> +  ...
>>> +  ret = -C;
>>> +  ...
>>> +  return ret;
>>> +} else S
>>
>>     Well, this seems to also cover the (e <= 0) checks which do make same sense
>> in the light of Linus considering IRQ0 invalid. So I'd be more specific about
>> the checks here -- 0 should indeed be overridden with something if it's
>> considered invalid.
>
> That's what the limitations section says (lines with #).  This doesn't

    Ah, failed to notice those, only saw after replying.

> make any changes, it only makes warnings, which should include the
> limitations information, so perhaps people can consider what it is that
> they really intend to do.
 >
> If you think this is not a good idea, then I can make the test more
> specific.

    Well, looking again, the patch should be good. I just thought its goal was 
to fix the code as well...

> julia

MBR, Sergei

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Julia Lawall Dec. 27, 2015, 6:13 a.m. UTC | #4
>    Well, looking again, the patch should be good. I just thought its goal was
> to fix the code as well...

I could do that for the irq < 0 case, but I think that in that case, kbuild
will only run the patch version, and the <= cases will not be reported on.
I don't have a general fix for the <= 0.  Is it even correct to have < in
some cases and <= in others?

julia
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SF Markus Elfring Dec. 27, 2015, 7:58 a.m. UTC | #5
> The error return value of platform_get_irq seems to often get dropped.

How do you think about any more fine-tuning here?

Commit message:
* … of the platform_get_irq() function seems to get dropped too often.

* Why do you concentrate on a single function name?
  Do you plan to extend this source code analysis approach?


> +@script:python r_report depends on report@
> +j0 << r.j0;
> +j1 << r.j1;
> +@@
> +
> +msg = "Propagate return value of platform_get_irq around line %s." % (j1[0].line)

Are there more unchecked return values which are interesting
for further considerations?
https://cwe.mitre.org/data/definitions/252.html

Regards,
Markus
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Sergei Shtylyov Dec. 27, 2015, 11:18 a.m. UTC | #6
On 12/27/2015 9:13 AM, Julia Lawall wrote:

>>     Well, looking again, the patch should be good. I just thought its goal was
>> to fix the code as well...
>
> I could do that for the irq < 0 case, but I think that in that case, kbuild
> will only run the patch version, and the <= cases will not be reported on.
> I don't have a general fix for the <= 0.  Is it even correct to have < in
> some cases and <= in others?

    That's a good question...
    In my prior fixes of this case I preferred to consider IRQ0 valid and so 
used 'irq < 0'. I myself don't share the "IRQ0 is invalid" sentiment...

> julia

MBR, Sergei

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Julia Lawall Dec. 27, 2015, 11:41 a.m. UTC | #7
On Sun, 27 Dec 2015, SF Markus Elfring wrote:

> > The error return value of platform_get_irq seems to often get dropped.
> 
> How do you think about any more fine-tuning here?
> 
> Commit message:
> * … of the platform_get_irq() function seems to get dropped too often.
> 
> * Why do you concentrate on a single function name?
>   Do you plan to extend this source code analysis approach?
> 
> 
> > +@script:python r_report depends on report@
> > +j0 << r.j0;
> > +j1 << r.j1;
> > +@@
> > +
> > +msg = "Propagate return value of platform_get_irq around line %s." % (j1[0].line)
> 
> Are there more unchecked return values which are interesting
> for further considerations?
> https://cwe.mitre.org/data/definitions/252.html

The value is not unchecked.  I made a specific rule because the specific 
problem is quite common.

julia
SF Markus Elfring Dec. 27, 2015, 4:24 p.m. UTC | #8
>> https://cwe.mitre.org/data/definitions/252.html
> 
> The value is not unchecked.

Would you like to express any stronger relationship between
the function call example and the occurrence of an if statement
by the discussed SmPL script?


> I made a specific rule because the specific problem is quite common.

Can it become also interesting to generalise this search pattern?

Regards,
Markus
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diff mbox

Patch

diff --git a/scripts/coccinelle/api/platform_get_irq_return.cocci b/scripts/coccinelle/api/platform_get_irq_return.cocci
new file mode 100644
index 0000000..44680d0
--- /dev/null
+++ b/scripts/coccinelle/api/platform_get_irq_return.cocci
@@ -0,0 +1,58 @@ 
+/// Propagate the return value of platform_get_irq.
+//# Sometimes the return value of platform_get_irq is tested using <= 0, but 0
+//# might not be an appropriate return value in an error case.
+///
+// Confidence: Moderate
+// Copyright: (C) 2015 Julia Lawall, Inria. GPLv2.
+// URL: http://coccinelle.lip6.fr/
+// Options: --no-includes --include-headers
+
+virtual context
+virtual org
+virtual report
+
+// ----------------------------------------------------------------------------
+
+@r depends on context || org || report@
+constant C;
+statement S;
+expression e, ret;
+position j0, j1;
+@@
+
+* e@j0 = platform_get_irq(...);
+(
+if@j1 (...) {
+  ...
+  return -C;
+} else S
+|
+if@j1 (...) {
+  ...
+  ret = -C;
+  ...
+  return ret;
+} else S
+)
+
+// ----------------------------------------------------------------------------
+
+@script:python r_org depends on org@
+j0 << r.j0;
+j1 << r.j1;
+@@
+
+msg = "Propagate return value of platform_get_irq."
+coccilib.org.print_todo(j0[0], msg)
+coccilib.org.print_link(j1[0], "")
+
+// ----------------------------------------------------------------------------
+
+@script:python r_report depends on report@
+j0 << r.j0;
+j1 << r.j1;
+@@
+
+msg = "Propagate return value of platform_get_irq around line %s." % (j1[0].line)
+coccilib.report.print_report(j0[0], msg)
+