From: qiwuchen55@gmail.com
To: kgene@kernel.org, krzk@kernel.org, rjw@rjwysocki.net,
viresh.kumar@linaro.org
Cc: linux-samsung-soc@vger.kernel.org, chenqiwu <chenqiwu@xiaomi.com>,
linux-arm-kernel@lists.infradead.org, linux-pm@vger.kernel.org
Subject: [PATCH v2] cpufreq: s3c: avoid use after free issue in xxx_cpufreq_reboot_notifier_evt()
Date: Mon, 6 Jan 2020 17:44:21 +0800 [thread overview]
Message-ID: <1578303861-7217-1-git-send-email-qiwuchen55@gmail.com> (raw)
From: chenqiwu <chenqiwu@xiaomi.com>
There is a potential UAF issue in xxx_cpufreq_reboot_notifier_evt() that
the cpufreq policy of cpu0 has been released before using it. So we should
make a judgement to avoid it.
Signed-off-by: chenqiwu <chenqiwu@xiaomi.com>
---
changes in v2:
- use the combination of cpufreq_cpu_get() and cpufreq_cpu_put()
instead of cpufreq_get_policy() in s3c2416-cpufreq.c
---
drivers/cpufreq/s3c2416-cpufreq.c | 12 +++++++++++-
drivers/cpufreq/s5pv210-cpufreq.c | 11 ++++++++++-
2 files changed, 21 insertions(+), 2 deletions(-)
diff --git a/drivers/cpufreq/s3c2416-cpufreq.c b/drivers/cpufreq/s3c2416-cpufreq.c
index 1069103..f07c5d1 100644
--- a/drivers/cpufreq/s3c2416-cpufreq.c
+++ b/drivers/cpufreq/s3c2416-cpufreq.c
@@ -304,6 +304,7 @@ static int s3c2416_cpufreq_reboot_notifier_evt(struct notifier_block *this,
{
struct s3c2416_data *s3c_freq = &s3c2416_cpufreq;
int ret;
+ struct cpufreq_policy *policy;
mutex_lock(&cpufreq_lock);
@@ -318,7 +319,16 @@ static int s3c2416_cpufreq_reboot_notifier_evt(struct notifier_block *this,
*/
if (s3c_freq->is_dvs) {
pr_debug("cpufreq: leave dvs on reboot\n");
- ret = cpufreq_driver_target(cpufreq_cpu_get(0), FREQ_SLEEP, 0);
+
+ policy = cpufreq_cpu_get(0);
+ if (!policy) {
+ pr_debug("cpufreq: get no policy for cpu0\n");
+ return NOTIFY_BAD;
+ }
+
+ ret = cpufreq_driver_target(&policy, FREQ_SLEEP, 0);
+ cpufreq_cpu_put(policy);
+
if (ret < 0)
return NOTIFY_BAD;
}
diff --git a/drivers/cpufreq/s5pv210-cpufreq.c b/drivers/cpufreq/s5pv210-cpufreq.c
index 5d10030..e84281e 100644
--- a/drivers/cpufreq/s5pv210-cpufreq.c
+++ b/drivers/cpufreq/s5pv210-cpufreq.c
@@ -555,8 +555,17 @@ static int s5pv210_cpufreq_reboot_notifier_event(struct notifier_block *this,
unsigned long event, void *ptr)
{
int ret;
+ struct cpufreq_policy *policy;
+
+ policy = cpufreq_cpu_get(0);
+ if (!policy) {
+ pr_debug("cpufreq: get no policy for cpu0\n");
+ return NOTIFY_BAD;
+ }
+
+ ret = cpufreq_driver_target(policy, SLEEP_FREQ, 0);
+ cpufreq_cpu_put(policy);
- ret = cpufreq_driver_target(cpufreq_cpu_get(0), SLEEP_FREQ, 0);
if (ret < 0)
return NOTIFY_BAD;
--
1.9.1
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next reply other threads:[~2020-01-06 9:44 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-06 9:44 qiwuchen55 [this message]
2020-01-07 5:31 ` [PATCH v2] cpufreq: s3c: avoid use after free issue in xxx_cpufreq_reboot_notifier_evt() Viresh Kumar
2020-01-07 7:50 ` chenqiwu
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