media: rc: uevent sysfs file races with rc_unregister_device()
commit 4f0835d667
upstream.
Only report uevent file contents if device still registered, else we
might read freed memory.
Reported-by: syzbot+ceef16277388d6f24898@syzkaller.appspotmail.com
Cc: Hillf Danton <hdanton@sina.com>
Cc: <stable@vger.kernel.org> # 4.16+
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
5.4-rM2-2.2.x-imx-squashed
parent
5925179bbc
commit
2d89e44dc9
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@ -1577,25 +1577,25 @@ static void rc_dev_release(struct device *device)
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kfree(dev);
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kfree(dev);
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}
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}
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#define ADD_HOTPLUG_VAR(fmt, val...) \
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do { \
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int err = add_uevent_var(env, fmt, val); \
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if (err) \
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return err; \
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} while (0)
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static int rc_dev_uevent(struct device *device, struct kobj_uevent_env *env)
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static int rc_dev_uevent(struct device *device, struct kobj_uevent_env *env)
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{
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{
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struct rc_dev *dev = to_rc_dev(device);
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struct rc_dev *dev = to_rc_dev(device);
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int ret = 0;
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if (dev->rc_map.name)
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mutex_lock(&dev->lock);
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ADD_HOTPLUG_VAR("NAME=%s", dev->rc_map.name);
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if (dev->driver_name)
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ADD_HOTPLUG_VAR("DRV_NAME=%s", dev->driver_name);
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if (dev->device_name)
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ADD_HOTPLUG_VAR("DEV_NAME=%s", dev->device_name);
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return 0;
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if (!dev->registered)
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ret = -ENODEV;
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if (ret == 0 && dev->rc_map.name)
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ret = add_uevent_var(env, "NAME=%s", dev->rc_map.name);
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if (ret == 0 && dev->driver_name)
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ret = add_uevent_var(env, "DRV_NAME=%s", dev->driver_name);
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if (ret == 0 && dev->device_name)
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ret = add_uevent_var(env, "DEV_NAME=%s", dev->device_name);
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mutex_unlock(&dev->lock);
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return ret;
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}
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}
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/*
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/*
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@ -1987,14 +1987,14 @@ void rc_unregister_device(struct rc_dev *dev)
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del_timer_sync(&dev->timer_keyup);
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del_timer_sync(&dev->timer_keyup);
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del_timer_sync(&dev->timer_repeat);
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del_timer_sync(&dev->timer_repeat);
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rc_free_rx_device(dev);
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mutex_lock(&dev->lock);
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mutex_lock(&dev->lock);
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if (dev->users && dev->close)
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if (dev->users && dev->close)
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dev->close(dev);
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dev->close(dev);
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dev->registered = false;
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dev->registered = false;
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mutex_unlock(&dev->lock);
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mutex_unlock(&dev->lock);
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rc_free_rx_device(dev);
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/*
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/*
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* lirc device should be freed with dev->registered = false, so
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* lirc device should be freed with dev->registered = false, so
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* that userspace polling will get notified.
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* that userspace polling will get notified.
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