2 files changed, 32 insertions, 6 deletions

diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
index d2b34fbbc42e..b6ded17b3be3 100644
--- a/drivers/input/evdev.c
+++ b/drivers/input/evdev.c
@@ -48,6 +48,7 @@ struct evdev_client {
         struct evdev *evdev;
         struct list_head node;
         int clkid;
+        bool revoked;
         unsigned int bufsize;
         struct input_event buffer[];
 };
@@ -164,6 +165,9 @@ static void evdev_pass_values(struct evdev_client *client,
         struct input_event event;
         bool wakeup = false;
 
+        if (client->revoked)
+                return;
+
         event.time = ktime_to_timeval(client->clkid == CLOCK_MONOTONIC ?
                                       mono : real);
 
@@ -240,7 +244,7 @@ static int evdev_flush(struct file *file, fl_owner_t id)
         if (retval)
                 return retval;
 
-        if (!evdev->exist)
+        if (!evdev->exist || client->revoked)
                 retval = -ENODEV;
         else
                 retval = input_flush_device(&evdev->handle, file);
@@ -429,7 +433,7 @@ static ssize_t evdev_write(struct file *file, const char __user *buffer,
         if (retval)
                 return retval;
 
-        if (!evdev->exist) {
+        if (!evdev->exist || client->revoked) {
                 retval = -ENODEV;
                 goto out;
         }
@@ -482,7 +486,7 @@ static ssize_t evdev_read(struct file *file, char __user *buffer,
                 return -EINVAL;
 
         for (;;) {
-                if (!evdev->exist)
+                if (!evdev->exist || client->revoked)
                         return -ENODEV;
 
                 if (client->packet_head == client->tail &&
@@ -511,7 +515,7 @@ static ssize_t evdev_read(struct file *file, char __user *buffer,
                 if (!(file->f_flags & O_NONBLOCK)) {
                         error = wait_event_interruptible(evdev->wait,
                                         client->packet_head != client->tail ||
-                                        !evdev->exist);
+                                        !evdev->exist || client->revoked);
                         if (error)
                                 return error;
                 }
@@ -529,7 +533,11 @@ static unsigned int evdev_poll(struct file *file, poll_table *wait)
 
         poll_wait(file, &evdev->wait, wait);
 
-        mask = evdev->exist ? POLLOUT | POLLWRNORM : POLLHUP | POLLERR;
+        if (evdev->exist && !client->revoked)
+                mask = POLLOUT | POLLWRNORM;
+        else
+                mask = POLLHUP | POLLERR;
+
         if (client->packet_head != client->tail)
                 mask |= POLLIN | POLLRDNORM;
 
@@ -795,6 +803,17 @@ static int evdev_handle_mt_request(struct input_dev *dev,
         return 0;
 }
 
+static int evdev_revoke(struct evdev *evdev, struct evdev_client *client,
+                        struct file *file)
+{
+        client->revoked = true;
+        evdev_ungrab(evdev, client);
+        input_flush_device(&evdev->handle, file);
+        wake_up_interruptible(&evdev->wait);
+
+        return 0;
+}
+
 static long evdev_do_ioctl(struct file *file, unsigned int cmd,
                            void __user *p, int compat_mode)
 {
@@ -857,6 +876,12 @@ static long evdev_do_ioctl(struct file *file, unsigned int cmd,
                 else
                         return evdev_ungrab(evdev, client);
 
+        case EVIOCREVOKE:
+                if (p)
+                        return -EINVAL;
+                else
+                        return evdev_revoke(evdev, client, file);
+
         case EVIOCSCLOCKID:
                 if (copy_from_user(&i, p, sizeof(unsigned int)))
                         return -EFAULT;
@@ -1002,7 +1027,7 @@ static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
         if (retval)
                 return retval;
 
-        if (!evdev->exist) {
+        if (!evdev->exist || client->revoked) {
                 retval = -ENODEV;
                 goto out;
         }
diff --git a/include/uapi/linux/input.h b/include/uapi/linux/input.h
index 2fb6fae50e90..d61c61c6d98f 100644
--- a/include/uapi/linux/input.h
+++ b/include/uapi/linux/input.h
@@ -152,6 +152,7 @@ struct input_keymap_entry {
 #define EVIOCGEFFECTS           _IOR('E', 0x84, int)                    /* Report number of effects playable at the same time */
 
 #define EVIOCGRAB               _IOW('E', 0x90, int)                    /* Grab/Release device */
+#define EVIOCREVOKE             _IOW('E', 0x91, int)                    /* Revoke device access */
 
 #define EVIOCSCLOCKID           _IOW('E', 0xa0, int)                    /* Set clockid to be used for timestamps */