From mboxrd@z Thu Jan 1 00:00:00 1970 From: Valdis.Kletnieks@vt.edu Subject: Re: [PATCH 2/3] Security: Implement disablenetwork semantics. (v4) Date: Mon, 18 Jan 2010 07:54:04 -0500 Message-ID: <17852.1263819244@localhost> References: <20100110215409.GA3705@heat> <20100110215848.GA26609@elf.ucw.cz> <5768.1263264853@localhost> <20100112075927.GA24256@atrey.karlin.mff.cuni.cz> <32558.1263306523@localhost> <20100114092250.GA11500@atrey.karlin.mff.cuni.cz> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="==_Exmh_1263819244_6729P"; micalg=pgp-sha1; protocol="application/pgp-signature" Content-Transfer-Encoding: 7bit Cc: Michael Stone , James Morris , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-security-module@vger.kernel.org, Andi Kleen , David Lang , Oliver Hartkopp , Alan Cox , Herbert Xu , Bryan Donlan , Evgeniy Polyakov , "C. Scott Ananian" , "Eric W. Biederman" , Bernie Innocenti , Mark Seaborn , Randy Dunlap , Am?rico Wang , Tetsuo Handa , Samir Bellabes , Casey Schaufler , "Serge E. Hallyn" , Al Viro To: Pavel Machek Return-path: In-Reply-To: Your message of "Thu, 14 Jan 2010 10:22:51 +0100." <20100114092250.GA11500@atrey.karlin.mff.cuni.cz> Sender: linux-security-module-owner@vger.kernel.org List-Id: netdev.vger.kernel.org --==_Exmh_1263819244_6729P Content-Type: text/plain; charset=us-ascii On Thu, 14 Jan 2010 10:22:51 +0100, Pavel Machek said: > > On Tue, 12 Jan 2010 08:59:27 +0100, Pavel Machek said: > > > > > Well, maybe, but mailer system where first user starts is as a daemon > > > makes sense... > > > > Does it? How do you get port 25 open for listening if the first user isn't > > root? Most *actual* schemes to "launch at first use" that require privs fo r > > something have used inetd or similar - that program exists for a > > *reason*. > > Remember sendmail is setuid root... so it already has the permissions. Actually, the sendmail setuid bit was removed quite some time ago: 8.12.0/8.12.0 2001/09/08 *NOTICE*: The default installation of sendmail does not use set-user-ID root anymore. You need to create a new user and a new group before installing sendmail (both called smmsp by default). The installation process tries to install /etc/mail/submit.cf and creates /var/spool/clientmqueue by default. Please see sendmail/SECURITY for details. Wow. 2001. And people *still* think it's setuid. ;) (Interestingly enough, the capabilities bug came *later*: 8.12.1/8.12.1 2001/10/01 SECURITY: Check whether dropping group privileges actually succeeded to avoid possible compromises of the mail system by supplying bogus data. Add configuration options for different set*gid() calls to reset saved gid. Problem found by Michal Zalewski. and was mostly an issue because the same problem existed in pre-8.12 sendmails that were still setuid and hadn't upgraded yet... --==_Exmh_1263819244_6729P Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) Comment: Exmh version 2.5 07/13/2001 iD8DBQFLVFnscC3lWbTT17ARArPiAJ9gsFOaXOoPI0PtsT+jBlxoTh9CwQCfaEBQ AhZmttLo9rYq+6PtWIOHrRg= =taue -----END PGP SIGNATURE----- --==_Exmh_1263819244_6729P--