Fixed bug 3546 - SDL_EVDEV_is_console() uses type of wrong size when …

…calling ioctl Rob When calling ioctl(fd, KDGKBTYPE, &type) in SDL_EVDEV_is_console(), we declare type as an 'int'. This should be a 'char'. The subsequent syscall, and kernel code, only writes the lower byte of the word. See: http://lxr.free-electrons.com/source/drivers/tty/vt/vt_ioctl.c?v=4.4#L399 ucval = KB_101; ret = put_user(ucval, (char __user *)arg); I've observed intermittent behavior related to this, and I can force an error condition by using an int initialized to 0xFFFFFFFF. The resulting ioctl will set type to 0XFFFFFF02, and the conditional return in SDL_EVDEV_is_console() will fail. Recommend changing to char, or masking off unused bits.
libsdl-org · Jan 6, 2017 · 41be975 · 41be975
1 parent b3e8db8
commit 41be975
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/src/core/linux/SDL_evdev.c b/src/core/linux/SDL_evdev.c
@@ -150,7 +150,7 @@ static const char* EVDEV_consoles[] = {
 };
 
 static int SDL_EVDEV_is_console(int fd) {
-    int type;
+    char type;
 
     return isatty(fd) && ioctl(fd, KDGKBTYPE, &type) == 0 &&
         (type == KB_101 || type == KB_84);