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

From: Wen Yang
Date: Mon Jul 08 2019 - 02:21:27 EST


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@xxxxxxxxxx>
Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx>
Cc: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
Cc: linuxppc-dev@xxxxxxxxxxxxxxxx
Cc: linux-pm@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
drivers/cpufreq/pasemi-cpufreq.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/cpufreq/pasemi-cpufreq.c b/drivers/cpufreq/pasemi-cpufreq.c
index 6b1e4ab..d2dd47b 100644
--- a/drivers/cpufreq/pasemi-cpufreq.c
+++ b/drivers/cpufreq/pasemi-cpufreq.c
@@ -132,7 +132,6 @@ static int pas_cpufreq_cpu_init(struct cpufreq_policy *policy)

cpu = of_get_cpu_node(policy->cpu, NULL);

- of_node_put(cpu);
if (!cpu)
goto out;

@@ -141,15 +140,15 @@ static int pas_cpufreq_cpu_init(struct cpufreq_policy *policy)
dn = of_find_compatible_node(NULL, NULL,
"pasemi,pwrficient-sdc");
if (!dn)
- goto out;
+ goto out_put_cpu_node;
err = of_address_to_resource(dn, 0, &res);
of_node_put(dn);
if (err)
- goto out;
+ goto out_put_cpu_node;
sdcasr_mapbase = ioremap(res.start + SDCASR_OFFSET, 0x2000);
if (!sdcasr_mapbase) {
err = -EINVAL;
- goto out;
+ goto out_put_cpu_node;
}

dn = of_find_compatible_node(NULL, NULL, "1682m-gizmo");
@@ -177,6 +176,7 @@ static int pas_cpufreq_cpu_init(struct cpufreq_policy *policy)
err = -EINVAL;
goto out_unmap_sdcpwr;
}
+ of_node_put(cpu);

/* we need the freq in kHz */
max_freq = *max_freqp / 1000;
@@ -203,6 +203,8 @@ static int pas_cpufreq_cpu_init(struct cpufreq_policy *policy)

out_unmap_sdcasr:
iounmap(sdcasr_mapbase);
+out_put_cpu_node:
+ of_node_put(cpu);
out:
return err;
}
--
2.9.5