[PATCH 4.9 016/103] cpufreq/pasemi: fix use-after-free in pas_cpufreq_cpu_init()

Greg Kroah-Hartman
2019-08-22T17:44:34Z

[ Upstream commit e0a12445d1cb186d875410d093a00d215bec6a89 ]

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: a9acc26b75f6 ("cpufreq/pasemi: fix possible object reference leak")
Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/cpufreq/pasemi-cpufreq.c | 23 +++++++++--------------
1 file changed, 9 insertions(+), 14 deletions(-)

diff --git a/drivers/cpufreq/pasemi-cpufreq.c b/drivers/cpufreq/pasemi-cpufreq.c
index 58c933f483004..991b6a3062c4f 100644
--- a/drivers/cpufreq/pasemi-cpufreq.c
+++ b/drivers/cpufreq/pasemi-cpufreq.c
@@ -145,10 +145,18 @@ static int pas_cpufreq_cpu_init(struct cpufreq_policy *policy)
int err = -ENODEV;

cpu = of_get_cpu_node(policy->cpu, NULL);
+ if (!cpu)
+ goto out;

+ max_freqp = of_get_property(cpu, "clock-frequency", NULL);
of_node_put(cpu);
- if (!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)
@@ -185,16 +193,6 @@ 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");

@@ -212,9 +210,6 @@ static int pas_cpufreq_cpu_init(struct cpufreq_policy *policy)

return cpufreq_generic_init(policy, pas_freqs, get_gizmo_latency());

-out_unmap_sdcpwr:
- iounmap(sdcpwr_mapbase);
-
out_unmap_sdcasr:
iounmap(sdcasr_mapbase);
out:
--
2.20.1