Network-wide Mail Spool?

[James E. Leinweber]

karl_kleinpaste at cis.ohio-state.edu writes:

>Any reason why one couldn't place symlinks: ...
[making /usr/spool/mail/someone a link to ~someone/.newmail]

Mail is a traditional source of security holes in Unix, particularly in the
presence of symbolic links.  Be very careful around scenarios such as:

rm .newmail; ln -s /etc/passwd .newmail
echo "cracked::0:0:::/tmp" | mail $USER

If the mail delivery agent runs set-uid root, and the directory containing
the mail box is writeable by the user, and symbolic links are allowed in
mailbox paths, it had better be a community of trusted users. Also, if the
user mailbox lives under their home directory and you have disk quotas,
you could run into denial of service security risks too.
-- 
Jim Leinweber  (608)262-0736   State Lab. of Hygiene/U. of Wisconsin - Madison 
jiml at sente.slh.wisc.edu	       uunet!uwvax!uwslh!jiml        fax:(608)262-3257