1 files changed, 41 insertions, 27 deletions

diff --git a/drivers/input/joydev.c b/drivers/input/joydev.c
index 4cfd084fa897..9a1d55b74d7a 100644
--- a/drivers/input/joydev.c
+++ b/drivers/input/joydev.c
@@ -456,8 +456,11 @@ static int joydev_ioctl_common(struct joydev *joydev,
                                 unsigned int cmd, void __user *argp)
 {
         struct input_dev *dev = joydev->handle.dev;
+        size_t len;
         int i, j;
+        const char *name;
 
+        /* Process fixed-sized commands. */
         switch (cmd) {
 
         case JS_SET_CAL:
@@ -499,9 +502,22 @@ static int joydev_ioctl_common(struct joydev *joydev,
                 return copy_to_user(argp, joydev->corr,
                         sizeof(joydev->corr[0]) * joydev->nabs) ? -EFAULT : 0;
 
-        case JSIOCSAXMAP:
-                if (copy_from_user(joydev->abspam, argp,
-                                   sizeof(__u8) * (ABS_MAX + 1)))
+        }
+
+        /*
+         * Process variable-sized commands (the axis and button map commands
+         * are considered variable-sized to decouple them from the values of
+         * ABS_MAX and KEY_MAX).
+         */
+        switch (cmd & ~IOCSIZE_MASK) {
+
+        case (JSIOCSAXMAP & ~IOCSIZE_MASK):
+                len = min_t(size_t, _IOC_SIZE(cmd), sizeof(joydev->abspam));
+                /*
+                 * FIXME: we should not copy into our axis map before
+                 * validating the data.
+                 */
+                if (copy_from_user(joydev->abspam, argp, len))
                         return -EFAULT;
 
                 for (i = 0; i < joydev->nabs; i++) {
@@ -511,13 +527,17 @@ static int joydev_ioctl_common(struct joydev *joydev,
                 }
                 return 0;
 
-        case JSIOCGAXMAP:
-                return copy_to_user(argp, joydev->abspam,
-                        sizeof(__u8) * (ABS_MAX + 1)) ? -EFAULT : 0;
-
-        case JSIOCSBTNMAP:
-                if (copy_from_user(joydev->keypam, argp,
-                                   sizeof(__u16) * (KEY_MAX - BTN_MISC + 1)))
+        case (JSIOCGAXMAP & ~IOCSIZE_MASK):
+                len = min_t(size_t, _IOC_SIZE(cmd), sizeof(joydev->abspam));
+                return copy_to_user(argp, joydev->abspam, len) ? -EFAULT : 0;
+
+        case (JSIOCSBTNMAP & ~IOCSIZE_MASK):
+                len = min_t(size_t, _IOC_SIZE(cmd), sizeof(joydev->keypam));
+                /*
+                 * FIXME: we should not copy into our keymap before
+                 * validating the data.
+                 */
+                if (copy_from_user(joydev->keypam, argp, len))
                         return -EFAULT;
 
                 for (i = 0; i < joydev->nkey; i++) {
@@ -529,25 +549,19 @@ static int joydev_ioctl_common(struct joydev *joydev,
 
                 return 0;
 
-        case JSIOCGBTNMAP:
-                return copy_to_user(argp, joydev->keypam,
-                        sizeof(__u16) * (KEY_MAX - BTN_MISC + 1)) ? -EFAULT : 0;
+        case (JSIOCGBTNMAP & ~IOCSIZE_MASK):
+                len = min_t(size_t, _IOC_SIZE(cmd), sizeof(joydev->keypam));
+                return copy_to_user(argp, joydev->keypam, len) ? -EFAULT : 0;
 
-        default:
-                if ((cmd & ~IOCSIZE_MASK) == JSIOCGNAME(0)) {
-                        int len;
-                        const char *name = dev->name;
-
-                        if (!name)
-                                return 0;
-                        len = strlen(name) + 1;
-                        if (len > _IOC_SIZE(cmd))
-                                len = _IOC_SIZE(cmd);
-                        if (copy_to_user(argp, name, len))
-                                return -EFAULT;
-                        return len;
-                }
+        case JSIOCGNAME(0):
+                name = dev->name;
+                if (!name)
+                        return 0;
+
+                len = min_t(size_t, _IOC_SIZE(cmd), strlen(name) + 1);
+                return copy_to_user(argp, name, len) ? -EFAULT : len;
         }
+
         return -EINVAL;
 }