Description of problem:
There is a bug in the netkit-rsh-0.17-ipv6-rexec.patch when it generates the address for reporting when no DNS mode is selected (-D).

Version-Release number of selected component (if applicable):
rsh-0.17-92.fc31

How reproducible:
Always

Steps to Reproduce:
1. Edit /usr/lib/systemd/system/rexec@.service, add -D in the ExecStart line:
 ExecStart=-/usr/sbin/in.rexecd -D

2. Start rexec.socket:
 #systemctl start rexec.socket

3. Connect to rexec:
 #rexec -l <user> -p <passwd> localhost 'echo hello'

Actual results:
The address shown in log(audit for instance) is utter nonsense:
... msg='op=PAM:setcred grantors=pam_securetty,pam_localuser,pam_unix acct="test" exe="/usr/sbin/in.rexecd" hostname=a00:c63c:: addr=a00:c63c:: ...
 
Expected results:
... msg='op=PAM:setcred grantors=pam_securetty,pam_localuser,pam_unix acct="test" exe="/usr/sbin/in.rexecd" hostname=::1 addr=::1 ...

Additional info:
The lines

  if (from.ss_family == AF_INET)
    remote = inet_ntop(AF_INET, &from, remote_addr, INET_ADDRSTRLEN);
  else
    remote = inet_ntop(AF_INET6, &from, remote_addr, INET6_ADDRSTRLEN);

should be

  if (from.ss_family == AF_INET)
    remote = inet_ntop(AF_INET, &((struct sockaddr_in *) &from)->sin_addr,
                        remote_addr, INET_ADDRSTRLEN);
  else
    remote = inet_ntop(AF_INET6, &((struct sockaddr_in6 *) &from)->sin6_addr,
                        remote_addr, INET6_ADDRSTRLEN);