thermal: cpu_cooling: fix out of bounds access in time_in_idle

In __cpufreq_cooling_register() we allocate the arrays for time_in_idle
and time_in_idle_timestamp to be as big as the number of cpus in this
cpufreq device.  However, in get_load() we access this array using the
cpu number as index, which can result in an out of bound access.

Index time_in_idle{,_timestamp} using the index in the cpufreq_device's
allowed_cpus mask, as we do for the load_cpu array in
cpufreq_get_requested_power()

Reported-by: Nicolas Boichat <drinkcat@chromium.org>
Cc: Amit Daniel Kachhap <amit.kachhap@gmail.com>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Eduardo Valentin <edubezval@gmail.com>
Tested-by: Nicolas Boichat <drinkcat@chromium.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Javi Merino <javi.merino@arm.com>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>

diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c
index e3fbc5a5d88f166930e8633e671348614d00dd4d..6ceac4f2d4b227d52045632992568d08ea158c5b 100644 (file)
--- a/drivers/thermal/cpu_cooling.c
+++ b/drivers/thermal/cpu_cooling.c
@@ -377,26 +377,28 @@ static u32 cpu_power_to_freq(struct cpufreq_cooling_device *cpufreq_device,
  * get_load() - get load for a cpu since last updated
  * @cpufreq_device:    &struct cpufreq_cooling_device for this cpu
  * @cpu:       cpu number
+ * @cpu_idx:   index of the cpu in cpufreq_device->allowed_cpus
  *
  * Return: The average load of cpu @cpu in percentage since this
  * function was last called.
  */
-static u32 get_load(struct cpufreq_cooling_device *cpufreq_device, int cpu)
+static u32 get_load(struct cpufreq_cooling_device *cpufreq_device, int cpu,
+                   int cpu_idx)
 {
        u32 load;
        u64 now, now_idle, delta_time, delta_idle;
 
        now_idle = get_cpu_idle_time(cpu, &now, 0);
-       delta_idle = now_idle - cpufreq_device->time_in_idle[cpu];
-       delta_time = now - cpufreq_device->time_in_idle_timestamp[cpu];
+       delta_idle = now_idle - cpufreq_device->time_in_idle[cpu_idx];
+       delta_time = now - cpufreq_device->time_in_idle_timestamp[cpu_idx];
 
        if (delta_time <= delta_idle)
                load = 0;
        else
                load = div64_u64(100 * (delta_time - delta_idle), delta_time);
 
-       cpufreq_device->time_in_idle[cpu] = now_idle;
-       cpufreq_device->time_in_idle_timestamp[cpu] = now;
+       cpufreq_device->time_in_idle[cpu_idx] = now_idle;
+       cpufreq_device->time_in_idle_timestamp[cpu_idx] = now;
 
        return load;
 }
@@ -598,7 +600,7 @@ static int cpufreq_get_requested_power(struct thermal_cooling_device *cdev,
                u32 load;
 
                if (cpu_online(cpu))
-                       load = get_load(cpufreq_device, cpu);
+                       load = get_load(cpufreq_device, cpu, i);
                else
                        load = 0;