Denial of Service possible with Pacemaker WebUI long password

Issue

• Its possible to hang the pacemaker service through pacemaker webui. Even after the restart of the servers, the problem does not disappear. The way to reproduce is to give a valid username and really long password to the password field on the webui.

• From the original report of CVE-2015-3238:

"If SELinux is enabled, the _unix_run_helper_binary function in Linux-PAM 1.1.8
and earlier hangs indefinitely when verifying a password of 65536 characters,
which allows attackers to conduct username enumeration and denial of service
attacks.

When supplying a password of 65536 characters or more, the process will block
on the write(2) call at modules/pam_unix/support.c:614 because it tries to
write strlen(passwd)+1 bytes to a blocking pipe and a pipe has a limited
capacity of 65536 bytes on Linux."