The copy_from_user function in the uaccess code in Linux kernel 2.6 before 2.6.19-rc1, when running on s390, does not properly clear a kernel buffer, which…

The copy_from_user function in the uaccess code in Linux kernel 2.6 before 2.6.19-rc1, when running on s390, does not properly clear a kernel buffer, which allows local user space programs to read portions of kernel memory by "appending to a file from a bad address," which triggers a fault that prevents the unused memory from being cleared in the kernel buffer.