Re: [PATCH v5] cpufreq/pasemi: fix an use-after-free in pas_cpufreq_cpu_init()
On Tuesday, July 9, 2019 10:12:05 AM CEST Viresh Kumar wrote:
> 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
> > Cc: "Rafael J. Wysocki"
> > Cc: Viresh Kumar
> > Cc: Michael Ellerman
> > Cc: linuxppc-...@lists.ozlabs.org
> > Cc: linux...@vger.kernel.org
> > Cc: linux-kernel@vger.kernel.org
Patch applied.
> > ---
> > 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 :)
And I added the blank line.
> > + 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
>
>
Thanks!
Re: [PATCH v5] cpufreq/pasemi: fix an use-after-free in pas_cpufreq_cpu_init()
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
> Cc: "Rafael J. Wysocki"
> Cc: Viresh Kumar
> Cc: Michael Ellerman
> Cc: linuxppc-...@lists.ozlabs.org
> Cc: linux...@vger.kernel.org
> Cc: linux-kernel@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
[PATCH v5] cpufreq/pasemi: fix an use-after-free in pas_cpufreq_cpu_init()
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
Cc: "Rafael J. Wysocki"
Cc: Viresh Kumar
Cc: Michael Ellerman
Cc: linuxppc-...@lists.ozlabs.org
Cc: linux...@vger.kernel.org
Cc: linux-kernel@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;
+ 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");
--
2.9.5
