Input: add support for large scancodes

Several devices use a high number of bits for scancodes. One important
group is the Remote Controllers. Some new protocols like RC-6 define a
scancode space of 64 bits.

The current EVIO[CS]GKEYCODE ioctls allow replace the scancode/keycode
translation tables, but it is limited to up to 32 bits for scancode.

Also, if userspace wants to clean the existing table, replacing it by
a new one, it needs to run a loop calling the ioctls over the entire
sparse scancode space.

To solve those problems, this patch extends the ioctls to allow drivers
handle scancodes up to 32 bytes long (the length could be extended in
the future should such need arise) and allow userspace to query and set
scancode to keycode mappings not only by scancode but also by index.

Compatibility code were also added to handle the old format of
EVIO[CS]GKEYCODE ioctls.

Folded fixes by:
- Dan Carpenter: locking fixes for the original implementation
- Jarod Wilson: fix crash when setting keycode and wiring up get/set
                handlers in original implementation.
- Dmitry Torokhov: rework to consolidate old and new scancode handling,
                   provide options to act either by index or scancode.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

1 files changed, 80 insertions, 20 deletions

diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
index c908c5f83645..1ce9bf663206 100644
--- a/drivers/input/evdev.c
+++ b/drivers/input/evdev.c
@@ -534,6 +534,80 @@ static int handle_eviocgbit(struct input_dev *dev,
 }
 #undef OLD_KEY_MAX
 
+static int evdev_handle_get_keycode(struct input_dev *dev,
+                                    void __user *p, size_t size)
+{
+        struct input_keymap_entry ke;
+        int error;
+
+        memset(&ke, 0, sizeof(ke));
+
+        if (size == sizeof(unsigned int[2])) {
+                /* legacy case */
+                int __user *ip = (int __user *)p;
+
+                if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
+                        return -EFAULT;
+
+                ke.len = sizeof(unsigned int);
+                ke.flags = 0;
+
+                error = input_get_keycode(dev, &ke);
+                if (error)
+                        return error;
+
+                if (put_user(ke.keycode, ip + 1))
+                        return -EFAULT;
+
+        } else {
+                size = min(size, sizeof(ke));
+
+                if (copy_from_user(&ke, p, size))
+                        return -EFAULT;
+
+                error = input_get_keycode(dev, &ke);
+                if (error)
+                        return error;
+
+                if (copy_to_user(p, &ke, size))
+                        return -EFAULT;
+        }
+        return 0;
+}
+
+static int evdev_handle_set_keycode(struct input_dev *dev,
+                                    void __user *p, size_t size)
+{
+        struct input_keymap_entry ke;
+
+        memset(&ke, 0, sizeof(ke));
+
+        if (size == sizeof(unsigned int[2])) {
+                /* legacy case */
+                int __user *ip = (int __user *)p;
+
+                if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
+                        return -EFAULT;
+
+                if (get_user(ke.keycode, ip + 1))
+                        return -EFAULT;
+
+                ke.len = sizeof(unsigned int);
+                ke.flags = 0;
+
+        } else {
+                size = min(size, sizeof(ke));
+
+                if (copy_from_user(&ke, p, size))
+                        return -EFAULT;
+
+                if (ke.len > sizeof(ke.scancode))
+                        return -EINVAL;
+        }
+
+        return input_set_keycode(dev, &ke);
+}
+
 static long evdev_do_ioctl(struct file *file, unsigned int cmd,
                            void __user *p, int compat_mode)
 {
@@ -580,25 +654,6 @@ static long evdev_do_ioctl(struct file *file, unsigned int cmd,
 
                 return 0;
 
-        case EVIOCGKEYCODE:
-                if (get_user(t, ip))
-                        return -EFAULT;
-
-                error = input_get_keycode(dev, t, &v);
-                if (error)
-                        return error;
-
-                if (put_user(v, ip + 1))
-                        return -EFAULT;
-
-                return 0;
-
-        case EVIOCSKEYCODE:
-                if (get_user(t, ip) || get_user(v, ip + 1))
-                        return -EFAULT;
-
-                return input_set_keycode(dev, t, v);
-
         case EVIOCRMFF:
                 return input_ff_erase(dev, (int)(unsigned long) p, file);
 
@@ -620,7 +675,6 @@ static long evdev_do_ioctl(struct file *file, unsigned int cmd,
 
         /* Now check variable-length commands */
 #define EVIOC_MASK_SIZE(nr)     ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT))
-
         switch (EVIOC_MASK_SIZE(cmd)) {
 
         case EVIOCGKEY(0):
@@ -654,6 +708,12 @@ static long evdev_do_ioctl(struct file *file, unsigned int cmd,
                         return -EFAULT;
 
                 return error;
+
+        case EVIOC_MASK_SIZE(EVIOCGKEYCODE):
+                return evdev_handle_get_keycode(dev, p, size);
+
+        case EVIOC_MASK_SIZE(EVIOCSKEYCODE):
+                return evdev_handle_set_keycode(dev, p, size);
         }
 
         /* Multi-number variable-length handlers */