Message-ID: <47DE73BF.3050202@imap.cc>
Date: Mon, 17 Mar 2008 14:35:59 +0100
From: Tilman Schmidt <tilman@imap.cc>
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; de-AT; rv:1.8.1.11) Gecko/20071128 SeaMonkey/1.1.7 Mnenhy/0.7.5.666
MIME-Version: 1.0
To: Benjamin Thery <ben.thery@gmail.com>
CC: Daniel Lezcano <dlezcano@fr.ibm.com>,
       Andrew Morton <akpm@linux-foundation.org>, linux-kernel@vger.kernel.org,
       netdev@vger.kernel.org, David Miller <davem@davemloft.net>,
       pekkas@netcore.fi, yoshfuji@linux-ipv6.org
Subject: Re: [2.6.25-rc5-mm1] regression: cannot run Postfix sendmail command
 as non-root
References: <20080311011434.ad8c8d7d.akpm@linux-foundation.org>	 <47D98510.60801@imap.cc> <47D9A8DF.30809@fr.ibm.com>	 <47D9C1F0.6050803@imap.cc> <47DE4B7B.9040504@fr.ibm.com> <939d53060803170550r46a7e93ex31c166fff86bcf50@mail.gmail.com>
In-Reply-To: <939d53060803170550r46a7e93ex31c166fff86bcf50@mail.gmail.com>
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Benjamin Thery schrieb:
> While googling for the error string, I found this link which report
> the same kind of
> error when Postfix is used with grsecurity (in 2006):
>=20
> http://blog.jensthebrain.de/archives/2006/12/11/IPv6-Probleme-mit-Postf=
ix-und-grsecurity
>=20
> I barely understand German so I'm not sure it is related to your proble=
m.

The userspace failure described there is indeed the same as mine:
Postfix' sendmail command tries to open "/proc/net/if_inet6"
which fails with EACCES.

But I have never installed grsecurity on this machine, and the
problem appeared for me only with kernel 2.6.25-rc5-mm1, not when
running kernel 2.6.25-rc5 on the same machine, so I guess the
cause must be something different.

What's also strange is that I can "cat /proc/net/if_inet6" from
the command line as the same non-root user with no problem at all.
strace of "cat /proc/net/if_inet6" has:

open("/proc/net/if_inet6", O_RDONLY|O_LARGEFILE) =3D 3

strace of "/usr/sbin/sendmail", however:

open("/proc/net/if_inet6", O_RDONLY) =3D -1 EACCES (Permission denied)

Both run as

ts@xenon:~> id
uid=3D1000(ts) gid=3D100(users) groups=3D0(root),14(uucp),16(dialout),33(=
video),100(users),112(bacula)

HTH
T.

--=20
Tilman Schmidt                    E-Mail: tilman@imap.cc
Bonn, Germany
Diese Nachricht besteht zu 100% aus wiederverwerteten Bits.
Unge=F6ffnet mindestens haltbar bis: (siehe R=FCckseite)


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