CVE-2018-12896

An issue was discovered in the Linux kernel through 4.17.3. An Integer Overflow in kernel/time/posix-timers.c in the POSIX timer code is caused by the way the overrun accounting works. Depending on interval and expiry time values, the overrun can be larger than INTMAX, but the accounting is int based. This basically makes the accounting values, which are visible to user space via timergetoverrun(2) and siginfo::sioverrun, random. For example, a local user can cause a denial of service (signed integer overflow) via crafted mmap, futex, timercreate, and timer_settime system calls.