soc: qcom: aoss: Fix the out of bound usage of cooling_devs

In "qmp_cooling_devices_register", the count value is initially
QMP_NUM_COOLING_RESOURCES, which is 2. Based on the initial count value,
the memory for cooling_devs is allocated. Then while calling the
"qmp_cooling_device_add" function, count value is post-incremented for
each child node.

This makes the out of bound access to the cooling_dev array. Fix it by
passing the QMP_NUM_COOLING_RESOURCES definition to devm_kzalloc() and
initializing the count to 0.

While at it, let's also free the memory allocated to cooling_dev if no
cooling device is found in DT and during unroll phase.

Cc: stable@vger.kernel.org # 5.4
Fixes: 05589b30b21a ("soc: qcom: Extend AOSS QMP driver to support resources that are used to wake up the SoC.")
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20210629153249.73428-1-manivannan.sadhasivam@linaro.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

diff --git a/drivers/soc/qcom/qcom_aoss.c b/drivers/soc/qcom/qcom_aoss.c
index 92a1af70a64922a0a05b9fc045825bce3ed6e22b..536c3e4114fb9da4fb2e37a6aad2f998532d9de3 100644 (file)
--- a/drivers/soc/qcom/qcom_aoss.c
+++ b/drivers/soc/qcom/qcom_aoss.c
@@ -476,12 +476,12 @@ static int qmp_cooling_device_add(struct qmp *qmp,
 static int qmp_cooling_devices_register(struct qmp *qmp)
 {
        struct device_node *np, *child;
-       int count = QMP_NUM_COOLING_RESOURCES;
+       int count = 0;
        int ret;
 
        np = qmp->dev->of_node;
 
-       qmp->cooling_devs = devm_kcalloc(qmp->dev, count,
+       qmp->cooling_devs = devm_kcalloc(qmp->dev, QMP_NUM_COOLING_RESOURCES,
                                         sizeof(*qmp->cooling_devs),
                                         GFP_KERNEL);
 
@@ -497,12 +497,16 @@ static int qmp_cooling_devices_register(struct qmp *qmp)
                        goto unroll;
        }
 
+       if (!count)
+               devm_kfree(qmp->dev, qmp->cooling_devs);
+
        return 0;
 
 unroll:
        while (--count >= 0)
                thermal_cooling_device_unregister
                        (qmp->cooling_devs[count].cdev);
+       devm_kfree(qmp->dev, qmp->cooling_devs);
 
        return ret;
 }