glibc: denial of service

• CVE-2016-3075 (denial of service)

The getnetbyname implementation in nss_dns contains a potentially
unbounded alloca call (in the form of a call to strdupa), leading to a
stack overflow (stack exhaustion) and a crash if getnetbyname is
invoked on a very long name.

• CVE-2016-5417 (denial of service)

The sockaddr_in6 allocated in resolv/res_init.c:317 is not freed,
leaking 28 bytes per thread using the resolver (according to valgrind).
The leak is triggered if name resolution functions are called in such a
way that internal resolver data structures are only initialized
partially. This issue may ultimately lead to denial of service by
leaking extensive amounts of memory.