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<bazsi@xxxxxxxxxx>
> > > >
> > > > Signed-off-by: Balazs Scheidler<bazsi@xxxxxxxxxx>
> > > > Signed-off-by: KOVACS Krisztian<hidden@xxxxxxxxxx>
> > > > ---
> > > > 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:
> <http://kerneltrap.org/mailarchive/linux-netdev/2010/7/5/6280572>
>
> 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
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