From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> mainline inclusion from mainline-v6.19 commit fe747d7112283f47169e9c16e751179a9b38611e category: bugfix bugzilla: https://atomgit.com/openeuler/kernel/issues/13842 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- In a few places in the Classmate laptop driver, code using the accel object may run before that object's address is stored in the driver data of the input device using it. For example, cmpc_accel_sensitivity_store_v4() is the "show" method of cmpc_accel_sensitivity_attr_v4 which is added in cmpc_accel_add_v4(), before calling dev_set_drvdata() for inputdev->dev. If the sysfs attribute is accessed prematurely, the dev_get_drvdata(&inputdev->dev) call in in cmpc_accel_sensitivity_store_v4() returns NULL which leads to a NULL pointer dereference going forward. Moreover, sysfs attributes using the input device are added before initializing that device by cmpc_add_acpi_notify_device() and if one of them is accessed before running that function, a NULL pointer dereference will occur. For example, cmpc_accel_sensitivity_attr_v4 is added before calling cmpc_add_acpi_notify_device() and if it is read prematurely, the dev_get_drvdata(&acpi->dev) call in cmpc_accel_sensitivity_show_v4() returns NULL which leads to a NULL pointer dereference going forward. Fix this by adding NULL pointer checks in all of the relevant places. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Link: https://patch.msgid.link/12825381.O9o76ZdvQC@rafael.j.wysocki Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Conflicts: drivers/platform/x86/classmate-laptop.c [Context conflicts.] Signed-off-by: Zeng Heng <zengheng4@huawei.com> --- drivers/platform/x86/classmate-laptop.c | 32 +++++++++++++++++++++++++ 1 file changed, 32 insertions(+) diff --git a/drivers/platform/x86/classmate-laptop.c b/drivers/platform/x86/classmate-laptop.c index 2edaea2492df..053c8a86d5ec 100644 --- a/drivers/platform/x86/classmate-laptop.c +++ b/drivers/platform/x86/classmate-laptop.c @@ -208,7 +208,12 @@ static ssize_t cmpc_accel_sensitivity_show_v4(struct device *dev, acpi = to_acpi_device(dev); inputdev = dev_get_drvdata(&acpi->dev); + if (!inputdev) + return -ENXIO; + accel = dev_get_drvdata(&inputdev->dev); + if (!accel) + return -ENXIO; return sprintf(buf, "%d\n", accel->sensitivity); } @@ -225,7 +230,12 @@ static ssize_t cmpc_accel_sensitivity_store_v4(struct device *dev, acpi = to_acpi_device(dev); inputdev = dev_get_drvdata(&acpi->dev); + if (!inputdev) + return -ENXIO; + accel = dev_get_drvdata(&inputdev->dev); + if (!accel) + return -ENXIO; r = kstrtoul(buf, 0, &sensitivity); if (r) @@ -257,7 +267,12 @@ static ssize_t cmpc_accel_g_select_show_v4(struct device *dev, acpi = to_acpi_device(dev); inputdev = dev_get_drvdata(&acpi->dev); + if (!inputdev) + return -ENXIO; + accel = dev_get_drvdata(&inputdev->dev); + if (!accel) + return -ENXIO; return sprintf(buf, "%d\n", accel->g_select); } @@ -274,7 +289,12 @@ static ssize_t cmpc_accel_g_select_store_v4(struct device *dev, acpi = to_acpi_device(dev); inputdev = dev_get_drvdata(&acpi->dev); + if (!inputdev) + return -ENXIO; + accel = dev_get_drvdata(&inputdev->dev); + if (!accel) + return -ENXIO; r = kstrtoul(buf, 0, &g_select); if (r) @@ -303,6 +323,8 @@ static int cmpc_accel_open_v4(struct input_dev *input) acpi = to_acpi_device(input->dev.parent); accel = dev_get_drvdata(&input->dev); + if (!accel) + return -ENXIO; cmpc_accel_set_sensitivity_v4(acpi->handle, accel->sensitivity); cmpc_accel_set_g_select_v4(acpi->handle, accel->g_select); @@ -551,7 +573,12 @@ static ssize_t cmpc_accel_sensitivity_show(struct device *dev, acpi = to_acpi_device(dev); inputdev = dev_get_drvdata(&acpi->dev); + if (!inputdev) + return -ENXIO; + accel = dev_get_drvdata(&inputdev->dev); + if (!accel) + return -ENXIO; return sprintf(buf, "%d\n", accel->sensitivity); } @@ -568,7 +595,12 @@ static ssize_t cmpc_accel_sensitivity_store(struct device *dev, acpi = to_acpi_device(dev); inputdev = dev_get_drvdata(&acpi->dev); + if (!inputdev) + return -ENXIO; + accel = dev_get_drvdata(&inputdev->dev); + if (!accel) + return -ENXIO; r = kstrtoul(buf, 0, &sensitivity); if (r) -- 2.25.1