====== Sendmail permmisions ======


Standard installation of sendmail-8.12+ requires to install sendmail binary as set group id.
(/usr/sbin/sendmail -> ... -> /usr/lib/sm.bin/sendmail in you case)

<code bash>
-rwxr-sr-x 1 root smmsp ...
</code>

In case of your softlinks chain try:

<code bash>
chown root:smmsp /usr/lib/sm.bin/sendmail
chmod 2555 /usr/lib/sm.bin/sendmail
</code>

Recommended permissions are described in SECURITY file in sendmail distribution. On my debian the file is installed as /usr/share/doc/sendmail-doc/sendmail/SECURITY.gz by sendmail-doc package.