From mboxrd@z Thu Jan 1 00:00:00 1970 From: Balazs Scheidler Subject: Re: [PATCH 5/9] tproxy: allow non-local binds of IPv6 sockets if IP_TRANSPARENT is enabled Date: Sat, 23 Oct 2010 16:48:14 +0200 Message-ID: <1287845294.13882.4.camel@bzorp.lan> References: <20101020112118.6260.31618.stgit@este.odu> <20101020112118.6260.93956.stgit@este.odu> <4CBEE45D.2080201@linux-ipv6.org> <1287583653.29676.9.camel@bzorp.lan> <1287696252.2707.24.camel@takos> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: KOVACS Krisztian , netdev@vger.kernel.org, netfilter-devel@vger.kernel.org, Patrick McHardy , David Miller To: YOSHIFUJI Hideaki Return-path: In-Reply-To: <1287696252.2707.24.camel@takos> Sender: netdev-owner@vger.kernel.org List-Id: netfilter-devel.vger.kernel.org On Fri, 2010-10-22 at 06:24 +0900, YOSHIFUJI Hideaki wrote: > Hello. > > 2010-10-20, Balazs Scheidler wrote: > > On Wed, 2010-10-20 at 21:45 +0900, YOSHIFUJI Hideaki wrote: > > > (2010/10/20 20:21), KOVACS Krisztian wrote: > > > > From: Balazs Scheidler > > > > > > > > Signed-off-by: Balazs Scheidler > > > > Signed-off-by: KOVACS Krisztian > > > > --- > > > > net/ipv6/af_inet6.c | 2 +- > > > > 1 files changed, 1 insertions(+), 1 deletions(-) > > > > > > > > diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c > > > > index 6022098..9480572 100644 > > > > --- a/net/ipv6/af_inet6.c > > > > +++ b/net/ipv6/af_inet6.c > > > > @@ -343,7 +343,7 @@ int inet6_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) > > > > */ > > > > v4addr = LOOPBACK4_IPV6; > > > > if (!(addr_type& IPV6_ADDR_MULTICAST)) { > > > > - if (!ipv6_chk_addr(net,&addr->sin6_addr, > > > > + if (!inet->transparent&& !ipv6_chk_addr(net,&addr->sin6_addr, > > > > dev, 0)) { > > > > err = -EADDRNOTAVAIL; > > > > goto out_unlock; > > > > > > > > > > > > > > As I wrote before in other thread, this does not seem sufficient -- > > > well, it is sufficient to allow non-local bind, but before we're > > > allowing this, we need add checks of source address in sending side. > > > > Can you please elaborate or point us to the other thread? Is it some > > kind of address-type check that we miss? > > Please see my comment at: > > > This will result in allowing non-privileged users easily sending from > non-local / unauthorized address, which is not good, and which should > not be allowed from security aspects. IP_TRANSPARENT requires root (more precisely CAP_NET_ADMIN privielges) for IPV6. However as I see right now this check was missed from the IPv6 implementation. Is that enough as a safeguard? e.g. something like this: diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c index 0553867..f683d2c 100644 --- a/net/ipv6/ipv6_sockglue.c +++ b/net/ipv6/ipv6_sockglue.c @@ -343,6 +343,10 @@ static int do_ipv6_setsockopt(struct sock *sk, int level, int optname, break; case IPV6_TRANSPARENT: + if (!capable(CAP_NET_ADMIN)) { + retv = -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 */ -- Bazsi