[PATCH v3] cpufreq/pasemi: fix an use-after-free in pas_cpufreq_cpu_init()

[PATCH v3] cpufreq/pasemi: fix an use-after-free in pas_cpufreq_cpu_init()

[Christian Zigotzky]

Hello Wen,

Thanks for your patch!

Did you test your patch with a P.A. Semi board?

Cheers,
Christian

Re:[PATCH v3] cpufreq/pasemi: fix an use-after-free inpas_cpufreq_cpu_init()

[wen.yang99]

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> Hello Wen,
> 
> Thanks for your patch!
> 
> Did you test your patch with a P.A. Semi board?
> 

Hello Christian, thank you.
We don't have a P.A. Semi board yet, so we didn't test it.
If you have such a board, could you please kindly help to test it?

--
Thanks and regards,
Wen

[PATCH v3] cpufreq/pasemi: fix an use-after-free inpas_cpufreq_cpu_init()

[Christian Zigotzky]

Is a final patch available for testing? Please do not release it without 
testing.

- Christian

On 09-07-19, 16:04, Wen Yang wrote:
 > The cpu variable is still being used in the of_get_property() call
 > after the of_node_put() call, which may result in use-after-free.
 >
 > Fixes: a9acc26b75f ("cpufreq/pasemi: fix possible object reference leak")
 > Signed-off-by: Wen Yang <wen.yang99 at zte.com.cn>
 > Cc: "Rafael J. Wysocki" <rjw at rjwysocki.net>
 > Cc: Viresh Kumar <viresh.kumar at linaro.org>
 > Cc: Michael Ellerman <mpe at ellerman.id.au>
 > Cc: linuxppc-dev at lists.ozlabs.org
 > Cc: linux-pm at vger.kernel.org
 > Cc: linux-kernel at vger.kernel.org
 > ---
 > v5: put together the code to get, use, and release cpu device_node.
 > v4: restore the blank line.
 > v3: fix a leaked reference.
 > v2: clean up the code according to the advice of viresh.
 >
 >  drivers/cpufreq/pasemi-cpufreq.c | 21 +++++++++------------
 >  1 file changed, 9 insertions(+), 12 deletions(-)
 >
 > diff --git a/drivers/cpufreq/pasemi-cpufreq.c 
b/drivers/cpufreq/pasemi-cpufreq.c
 > index 6b1e4ab..1f0beb7 100644
 > --- a/drivers/cpufreq/pasemi-cpufreq.c
 > +++ b/drivers/cpufreq/pasemi-cpufreq.c
 > @@ -131,10 +131,17 @@ static int pas_cpufreq_cpu_init(struct 
cpufreq_policy *policy)
 >      int err = -ENODEV;
 >
 >      cpu = of_get_cpu_node(policy->cpu, NULL);
 > -
 > -    of_node_put(cpu);
 >      if (!cpu)
 >          goto out;

I would have loved a blank line here :)

 > +    max_freqp = of_get_property(cpu, "clock-frequency", NULL);
 > +    of_node_put(cpu);
 > +    if (!max_freqp) {
 > +        err = -EINVAL;
 > +        goto out;
 > +    }
 > +
 > +    /* we need the freq in kHz */
 > +    max_freq = *max_freqp / 1000;
 >
 >      dn = of_find_compatible_node(NULL, NULL, "1682m-sdc");
 >      if (!dn)
 > @@ -171,16 +178,6 @@ static int pas_cpufreq_cpu_init(struct 
cpufreq_policy *policy)
 >      }
 >
 >      pr_debug("init cpufreq on CPU %d\n", policy->cpu);
 > -
 > -    max_freqp = of_get_property(cpu, "clock-frequency", NULL);
 > -    if (!max_freqp) {
 > -        err = -EINVAL;
 > -        goto out_unmap_sdcpwr;
 > -    }
 > -
 > -    /* we need the freq in kHz */
 > -    max_freq = *max_freqp / 1000;
 > -
 >      pr_debug("max clock-frequency is at %u kHz\n", max_freq);
 >      pr_debug("initializing frequency table\n");

Though, enough versions have happened now.

Acked-by: Viresh Kumar <viresh.kumar at linaro.org>

-- 
viresh

[PATCH v7] cpufreq/pasemi: fix an use-after-free inpas_cpufreq_cpu_init()

[Christian Zigotzky]

On 09.07.2019 at 03:39am, wen.yang99@zte.com.cn wrote:
>> Hello Wen,
>>
>> Thanks for your patch!
>>
>> Did you test your patch with a P.A. Semi board?
>>
> Hello Christian, thank you.
> We don't have a P.A. Semi board yet, so we didn't test it.
> If you have such a board, could you please kindly help to test it?
>
> --
> Thanks and regards,
> Wen

Hello Wen,

I successfully tested your pasemi cpufreq modifications with my P.A. 
Semi board [1] today.

First I patched the latest Git kernel with Viresh Kumar's patch [2]. 
After that I was able to patch the latest Git kernel with your v7 patch [3].

Then the kernel compiled without any errors.

Afterwards I successfully tested the new Git kernel with some cpufreq 
governors on openSUSE Tumbleweed 20190521 PowerPC64 [4] and on ubuntu 
MATE 16.04.6 LTS PowerPC32.

Thanks a lot for your work!

Tested-by: Christian Zigotzky <chzigotzky@xenosoft.de>

Cheers,
Christian

[1] https://en.wikipedia.org/wiki/AmigaOne_X1000
[2] 
https://lore.kernel.org/lkml/ee8cf5fb4b4a01fdf9199037ff6d835b935cfd13.1562902877.git.viresh.kumar@linaro.org/#Z30drivers:cpufreq:pasemi-cpufreq.c
[3] https://lists.ozlabs.org/pipermail/linuxppc-dev/2019-July/193735.html
[4] Screenshots: 
https://i.pinimg.com/originals/37/66/93/37669306cbc909a9d79270a849d18aa6.png 
and 
https://i.pinimg.com/originals/fe/f8/bf/fef8bfc90d95b5ae9cf31e175e8ba2da.png

Re:[PATCH v7] cpufreq/pasemi: fix an use-after-freeinpas_cpufreq_cpu_init()

[wen.yang99]

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>>> Hello Wen,
>>>
>>> Thanks for your patch!
>>>
>>> Did you test your patch with a P.A. Semi board?
>>>
>> Hello Christian, thank you.
>> We don't have a P.A. Semi board yet, so we didn't test it.
>> If you have such a board, could you please kindly help to test it?
>>
>> --
>> Thanks and regards,
>> Wen
> 
> Hello Wen,
> 
> I successfully tested your pasemi cpufreq modifications with my P.A.
> Semi board [1] today.
> 
> First I patched the latest Git kernel with Viresh Kumar's patch [2].
> After that I was able to patch the latest Git kernel with your v7 patch [3].
> 
> Then the kernel compiled without any errors.
> 
> Afterwards I successfully tested the new Git kernel with some cpufreq
> governors on openSUSE Tumbleweed 20190521 PowerPC64 [4] and on ubuntu
> MATE 16.04.6 LTS PowerPC32.
> 
> Thanks a lot for your work!
> 
> Tested-by: Christian Zigotzky <chzigotzky@xenosoft.de>
> 
> Cheers,
> Christian

Thank you very much!
--
Cheers,
Wen

> [1] https://en.wikipedia.org/wiki/AmigaOne_X1000
> [2]
> https://lore.kernel.org/lkml/ee8cf5fb4b4a01fdf9199037ff6d835b935cfd13.1562902877.git.viresh.kumar@linaro.org/#Z30drivers:cpufreq:pasemi-cpufreq.c
> [3] https://lists.ozlabs.org/pipermail/linuxppc-dev/2019-July/193735.html
> [4] Screenshots:
> https://i.pinimg.com/originals/37/66/93/37669306cbc909a9d79270a849d18aa6.png
> and
> https://i.pinimg.com/originals/fe/f8/bf/fef8bfc90d95b5ae9cf31e175e8ba2da.png