Fixed bug 1337 - joystick crash due to heap corruption with btnx

src/joystick/SDL_joystick.c

@@ -427,6 +427,11 @@ SDL_PrivateJoystickAxis(SDL_Joystick * joystick, Uint8 axis, Sint16 value)
 {
     int posted;
 
+    /* Make sure we're not getting garbage events */
+    if (axis >= joystick->naxes) {
+        return 0;
+    }
+
     /* Update internal joystick state */
     joystick->axes[axis] = value;
 
@@ -454,6 +459,11 @@ SDL_PrivateJoystickHat(SDL_Joystick * joystick, Uint8 hat, Uint8 value)
 {
     int posted;
 
+    /* Make sure we're not getting garbage events */
+    if (hat >= joystick->nhats) {
+        return 0;
+    }
+
     /* Update internal joystick state */
     joystick->hats[hat] = value;
 
@@ -482,6 +492,11 @@ SDL_PrivateJoystickBall(SDL_Joystick * joystick, Uint8 ball,
 {
     int posted;
 
+    /* Make sure we're not getting garbage events */
+    if (ball >= joystick->nballs) {
+        return 0;
+    }
+
     /* Update internal mouse state */
     joystick->balls[ball].dx += xrel;
     joystick->balls[ball].dy += yrel;
@@ -526,6 +541,11 @@ SDL_PrivateJoystickButton(SDL_Joystick * joystick, Uint8 button, Uint8 state)
     }
 #endif /* !SDL_EVENTS_DISABLED */
 
+    /* Make sure we're not getting garbage events */
+    if (button >= joystick->nbuttons) {
+        return 0;
+    }
+
     /* Update internal joystick state */
     joystick->buttons[button] = state;