Another FreeBSD/sendmail permissions question

[Kevin Stevens]

Not sure where this goes; I'm also posting it to the sendmail Usenet
group.

I've been having what is apparently a fairly common problem with my
sendmail configuration; every time a message is delivered I get a warning
of the type "Aug  5 00:25:53 babelfish sendmail[39666]: h757PrRD039666:
forward /data/mail/.forward+: Group writable directory".

After doing some research, I've been able to turn off the warning messages
using the DontBlameSendmail option in my .cf file.  However, I'd really
like to understand why the warning is being generated in the first place.

/data/mail is the user directory to which mail is delivered by my IMAP
server after it is moved from /var/mail/imap.

a)  There is no .forward file in /data/mail
b)  The permissions on the /data/mail directory are:
	drwx------  4 imap  wheel  512 Aug  5 10:00 .
c)  The permissions on the *parent* (/data) directory are:
	drwxrwxr-x  18 root  staff       512 Aug  2 13:52 ..
d)  Permissions on /var/mail/USERNAME are:
	-rw-------   1 imap     imap       0 Aug  5 10:03 imap
e)  Permissions on /var/mail are:
	drwxrwxr-x  2 root  mail  512 Aug  5 10:02 .
f)  And on /var are:
	drwxr-xr-x  23 root  wheel  512 May 10 23:23 .

Now, what's confusing to me is that if I remove the group writable
attribute of /data, the messages go away.  WTF?  Why does sendmail care
about the permissions of the *parent* directory?  Is this because someone
in the parent could alter or blow away the /data/mail directory?

I'd think that, if anything, the problem would be the permissions on the
/var/mail directory; but not only is that not where the warning
references; tightening permissions in that area doesn't affect the
warnings.

KeS