From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?q?Maciej=20=C5=BBenczykowski?= Subject: [PATCH] net: change capability used by socket options IP{,V6}_TRANSPARENT Date: Mon, 17 Oct 2011 15:16:23 -0700 Message-ID: <1318889783-23183-1-git-send-email-zenczykowski@gmail.com> References: <20110920.154213.888729603269720228.davem@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: netdev@vger.kernel.org, Balazs Scheidler , =?UTF-8?q?Maciej=20=C5=BBenczykowski?= To: =?UTF-8?q?Maciej=20=C5=BBenczykowski?= Return-path: Received: from mail-yw0-f46.google.com ([209.85.213.46]:49811 "EHLO mail-yw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751414Ab1JQWQj (ORCPT ); Mon, 17 Oct 2011 18:16:39 -0400 Received: by ywf7 with SMTP id 7so1096858ywf.19 for ; Mon, 17 Oct 2011 15:16:39 -0700 (PDT) In-Reply-To: <20110920.154213.888729603269720228.davem@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: =46rom: Maciej =C5=BBenczykowski Up till now the IP{,V6}_TRANSPARENT socket options (which actually set the same bit in the socket struct) have required CAP_NET_ADMIN privileges to set or clear the option. - we make clearing the bit not require any privileges. - we deprecate using CAP_NET_ADMIN for this purpose. - we allow CAP_NET_RAW to set this bit, because raw sockets already effectively allow you to emulate socket transparency. - we print a warning (but allow it) if you try to set the socket option with CAP_NET_ADMIN privs, but without CAP_NET_RAW. Signed-off-by: Maciej =C5=BBenczykowski --- include/linux/capability.h | 3 ++- net/ipv4/ip_sockglue.c | 20 ++++++++++++++++---- net/ipv6/ipv6_sockglue.c | 23 ++++++++++++++++++----- 3 files changed, 36 insertions(+), 10 deletions(-) diff --git a/include/linux/capability.h b/include/linux/capability.h index c421123..ce34ae3 100644 --- a/include/linux/capability.h +++ b/include/linux/capability.h @@ -198,7 +198,7 @@ struct cpu_vfs_cap_data { /* Allow modification of routing tables */ /* Allow setting arbitrary process / process group ownership on sockets */ -/* Allow binding to any address for transparent proxying */ +/* Allow binding to any address for transparent proxying (deprecated) = */ /* Allow setting TOS (type of service) */ /* Allow setting promiscuous mode */ /* Allow clearing driver statistics */ @@ -210,6 +210,7 @@ struct cpu_vfs_cap_data { =20 /* Allow use of RAW sockets */ /* Allow use of PACKET sockets */ +/* Allow binding to any address for transparent proxying */ =20 #define CAP_NET_RAW 13 =20 diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c index 8905e92..74f7d30 100644 --- a/net/ipv4/ip_sockglue.c +++ b/net/ipv4/ip_sockglue.c @@ -961,12 +961,24 @@ mc_msf_out: break; =20 case IP_TRANSPARENT: - if (!capable(CAP_NET_ADMIN)) { - err =3D -EPERM; - break; - } if (optlen < 1) goto e_inval; + /* Always allow clearing the transparent proxy socket option. + * The pre-3.2 permission for setting this was CAP_NET_ADMIN, + * and this is still supported - but deprecated. As of Linux + * 3.2 the proper permission is CAP_NET_RAW. + */ + if (!!val && !capable(CAP_NET_RAW)) { + if (!capable(CAP_NET_ADMIN)) { + err =3D -EPERM; + break; + } + printk_once(KERN_WARNING "%s (%d): " + "deprecated: attempt to set socket option " + "IP_TRANSPARENT with CAP_NET_ADMIN but " + "without CAP_NET_RAW.\n", + current->comm, task_pid_nr(current)); + } inet->transparent =3D !!val; break; =20 diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c index 2fbda5f..7c4f5ce 100644 --- a/net/ipv6/ipv6_sockglue.c +++ b/net/ipv6/ipv6_sockglue.c @@ -343,13 +343,26 @@ static int do_ipv6_setsockopt(struct sock *sk, in= t level, int optname, break; =20 case IPV6_TRANSPARENT: - if (!capable(CAP_NET_ADMIN)) { - retv =3D -EPERM; - break; - } if (optlen < sizeof(int)) goto e_inval; - /* we don't have a separate transparent bit for IPV6 we use the one = in the IPv4 socket */ + /* Always allow clearing the transparent proxy socket option. + * The pre-3.2 permission for setting this was CAP_NET_ADMIN, + * and this is still supported - but deprecated. As of Linux + * 3.2 the proper permission is CAP_NET_RAW. + */ + if (valbool && !capable(CAP_NET_RAW)) { + if (!capable(CAP_NET_ADMIN)) { + retv =3D -EPERM; + break; + } + printk_once(KERN_WARNING "%s (%d): " + "deprecated: attempt to set socket option " + "IPV6_TRANSPARENT with CAP_NET_ADMIN but " + "without CAP_NET_RAW.\n", + current->comm, task_pid_nr(current)); + } + /* we don't have a separate transparent bit for IPv6, + * so we just use the one in the IPv4 socket */ inet_sk(sk)->transparent =3D valbool; retv =3D 0; break; --=20 1.7.3.1