* Re: [PATCH] netfilter: check if the socket netns is correct. @ 2018-09-27 20:46 Guenter Roeck 2018-09-27 22:58 ` Flavio Leitner 0 siblings, 1 reply; 4+ messages in thread From: Guenter Roeck @ 2018-09-27 20:46 UTC (permalink / raw) To: Flavio Leitner Cc: Pablo Neira Ayuso, Jozsef Kadlecsik, Florian Westphal, David S. Miller, Alexey Kuznetsov, Hideaki YOSHIFUJI, netfilter-devel, coreteam, netdev, linux-kernel Hi Flavio, On Wed, Jun 27, 2018 at 10:34:25AM -0300, Flavio Leitner wrote: > Netfilter assumes that if the socket is present in the skb, then > it can be used because that reference is cleaned up while the skb > is crossing netns. > > We want to change that to preserve the socket reference in a future > patch, so this is a preparation updating netfilter to check if the > socket netns matches before use it. > > Signed-off-by: Flavio Leitner <fbl@redhat.com> > Acked-by: Florian Westphal <fw@strlen.de> > Signed-off-by: David S. Miller <davem@davemloft.net> > --- ... > --- a/net/netfilter/xt_socket.c > +++ b/net/netfilter/xt_socket.c > @@ -56,8 +56,12 @@ socket_match(const struct sk_buff *skb, struct xt_action_param *par, > struct sk_buff *pskb = (struct sk_buff *)skb; > struct sock *sk = skb->sk; > > + if (!net_eq(xt_net(par), sock_net(sk))) > + sk = NULL; > + I am having trouble with this code. With CONFIG_NET_NS enabled, it crashes for me in read_pnet() because sk is NULL. > if (!sk) > sk = nf_sk_lookup_slow_v4(xt_net(par), skb, xt_in(par)); The old code seems to suggest that sk == NULL was possible. I see the problem with the Chrome OS kernel rebased to v4.19-rc5, so I can not guarantee that this really an upstream problem. The change seems odd, though. Are you sure that it is not (or, rather, no longer) necessary to check if sk == NULL before dereferencing it in sock_net() ? > + > if (sk) { > bool wildcard; > bool transparent = true; > @@ -113,8 +117,12 @@ socket_mt6_v1_v2_v3(const struct sk_buff *skb, struct xt_action_param *par) > struct sk_buff *pskb = (struct sk_buff *)skb; > struct sock *sk = skb->sk; > > + if (!net_eq(xt_net(par), sock_net(sk))) > + sk = NULL; > + Same here. > if (!sk) > sk = nf_sk_lookup_slow_v6(xt_net(par), skb, xt_in(par)); > + > if (sk) { > bool wildcard; > bool transparent = true; Thanks, Guenter ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] netfilter: check if the socket netns is correct. 2018-09-27 20:46 [PATCH] netfilter: check if the socket netns is correct Guenter Roeck @ 2018-09-27 22:58 ` Flavio Leitner 2018-09-27 23:08 ` Guenter Roeck 2018-09-28 8:33 ` Pablo Neira Ayuso 0 siblings, 2 replies; 4+ messages in thread From: Flavio Leitner @ 2018-09-27 22:58 UTC (permalink / raw) To: Guenter Roeck Cc: Pablo Neira Ayuso, Jozsef Kadlecsik, Florian Westphal, David S. Miller, Alexey Kuznetsov, Hideaki YOSHIFUJI, netfilter-devel, coreteam, netdev, linux-kernel On Thu, Sep 27, 2018 at 01:46:29PM -0700, Guenter Roeck wrote: > Hi Flavio, > > On Wed, Jun 27, 2018 at 10:34:25AM -0300, Flavio Leitner wrote: > > Netfilter assumes that if the socket is present in the skb, then > > it can be used because that reference is cleaned up while the skb > > is crossing netns. > > > > We want to change that to preserve the socket reference in a future > > patch, so this is a preparation updating netfilter to check if the > > socket netns matches before use it. > > > > Signed-off-by: Flavio Leitner <fbl@redhat.com> > > Acked-by: Florian Westphal <fw@strlen.de> > > Signed-off-by: David S. Miller <davem@davemloft.net> > > --- > ... > > --- a/net/netfilter/xt_socket.c > > +++ b/net/netfilter/xt_socket.c > > @@ -56,8 +56,12 @@ socket_match(const struct sk_buff *skb, struct xt_action_param *par, > > struct sk_buff *pskb = (struct sk_buff *)skb; > > struct sock *sk = skb->sk; > > > > + if (!net_eq(xt_net(par), sock_net(sk))) > > + sk = NULL; > > + > > I am having trouble with this code. With CONFIG_NET_NS enabled, it crashes > for me in read_pnet() because sk is NULL. > > > if (!sk) > > sk = nf_sk_lookup_slow_v4(xt_net(par), skb, xt_in(par)); > > The old code seems to suggest that sk == NULL was possible. > > I see the problem with the Chrome OS kernel rebased to v4.19-rc5, so I > can not guarantee that this really an upstream problem. The change seems > odd, though. Are you sure that it is not (or, rather, no longer) necessary > to check if sk == NULL before dereferencing it in sock_net() ? Oops, it is necessary but if it's not and the netns doesn't match, we need do the lookup. So, could you check if this fixes the problem for you? >From a5f927e7f1368d753f87cb978d630d786d5adb62 Mon Sep 17 00:00:00 2001 From: Flavio Leitner <fbl@redhat.com> Date: Thu, 27 Sep 2018 19:36:28 -0300 Subject: [PATCH] xt_socket: check sk before checking for netns. Only check for the network namespace if the socket is available. Fixes: f564650106a6 ("netfilter: check if the socket netns is correct.") Reported-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Flavio Leitner <fbl@redhat.com> --- net/netfilter/xt_socket.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/netfilter/xt_socket.c b/net/netfilter/xt_socket.c index 0472f3472842..ada144e5645b 100644 --- a/net/netfilter/xt_socket.c +++ b/net/netfilter/xt_socket.c @@ -56,7 +56,7 @@ socket_match(const struct sk_buff *skb, struct xt_action_param *par, struct sk_buff *pskb = (struct sk_buff *)skb; struct sock *sk = skb->sk; - if (!net_eq(xt_net(par), sock_net(sk))) + if (sk && !net_eq(xt_net(par), sock_net(sk))) sk = NULL; if (!sk) @@ -117,7 +117,7 @@ socket_mt6_v1_v2_v3(const struct sk_buff *skb, struct xt_action_param *par) struct sk_buff *pskb = (struct sk_buff *)skb; struct sock *sk = skb->sk; - if (!net_eq(xt_net(par), sock_net(sk))) + if (sk && !net_eq(xt_net(par), sock_net(sk))) sk = NULL; if (!sk) -- 2.14.4 ^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] netfilter: check if the socket netns is correct. 2018-09-27 22:58 ` Flavio Leitner @ 2018-09-27 23:08 ` Guenter Roeck 2018-09-28 8:33 ` Pablo Neira Ayuso 1 sibling, 0 replies; 4+ messages in thread From: Guenter Roeck @ 2018-09-27 23:08 UTC (permalink / raw) To: Flavio Leitner Cc: Pablo Neira Ayuso, Jozsef Kadlecsik, Florian Westphal, David S. Miller, Alexey Kuznetsov, Hideaki YOSHIFUJI, netfilter-devel, coreteam, netdev, linux-kernel On Thu, Sep 27, 2018 at 07:58:24PM -0300, Flavio Leitner wrote: > On Thu, Sep 27, 2018 at 01:46:29PM -0700, Guenter Roeck wrote: > > Hi Flavio, > > > > On Wed, Jun 27, 2018 at 10:34:25AM -0300, Flavio Leitner wrote: > > > Netfilter assumes that if the socket is present in the skb, then > > > it can be used because that reference is cleaned up while the skb > > > is crossing netns. > > > > > > We want to change that to preserve the socket reference in a future > > > patch, so this is a preparation updating netfilter to check if the > > > socket netns matches before use it. > > > > > > Signed-off-by: Flavio Leitner <fbl@redhat.com> > > > Acked-by: Florian Westphal <fw@strlen.de> > > > Signed-off-by: David S. Miller <davem@davemloft.net> > > > --- > > ... > > > --- a/net/netfilter/xt_socket.c > > > +++ b/net/netfilter/xt_socket.c > > > @@ -56,8 +56,12 @@ socket_match(const struct sk_buff *skb, struct xt_action_param *par, > > > struct sk_buff *pskb = (struct sk_buff *)skb; > > > struct sock *sk = skb->sk; > > > > > > + if (!net_eq(xt_net(par), sock_net(sk))) > > > + sk = NULL; > > > + > > > > I am having trouble with this code. With CONFIG_NET_NS enabled, it crashes > > for me in read_pnet() because sk is NULL. > > > > > if (!sk) > > > sk = nf_sk_lookup_slow_v4(xt_net(par), skb, xt_in(par)); > > > > The old code seems to suggest that sk == NULL was possible. > > > > I see the problem with the Chrome OS kernel rebased to v4.19-rc5, so I > > can not guarantee that this really an upstream problem. The change seems > > odd, though. Are you sure that it is not (or, rather, no longer) necessary > > to check if sk == NULL before dereferencing it in sock_net() ? > > Oops, it is necessary but if it's not and the netns doesn't match, we need > do the lookup. So, could you check if this fixes the problem for you? > > From a5f927e7f1368d753f87cb978d630d786d5adb62 Mon Sep 17 00:00:00 2001 > From: Flavio Leitner <fbl@redhat.com> > Date: Thu, 27 Sep 2018 19:36:28 -0300 > Subject: [PATCH] xt_socket: check sk before checking for netns. > > Only check for the network namespace if the socket is available. > > Fixes: f564650106a6 ("netfilter: check if the socket netns is correct.") > Reported-by: Guenter Roeck <linux@roeck-us.net> > Signed-off-by: Flavio Leitner <fbl@redhat.com> This fixes the problem for me. Tested-by: Guenter Roeck <linux@roeck-us.net> Thanks, Guenter > --- > net/netfilter/xt_socket.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/net/netfilter/xt_socket.c b/net/netfilter/xt_socket.c > index 0472f3472842..ada144e5645b 100644 > --- a/net/netfilter/xt_socket.c > +++ b/net/netfilter/xt_socket.c > @@ -56,7 +56,7 @@ socket_match(const struct sk_buff *skb, struct xt_action_param *par, > struct sk_buff *pskb = (struct sk_buff *)skb; > struct sock *sk = skb->sk; > > - if (!net_eq(xt_net(par), sock_net(sk))) > + if (sk && !net_eq(xt_net(par), sock_net(sk))) > sk = NULL; > > if (!sk) > @@ -117,7 +117,7 @@ socket_mt6_v1_v2_v3(const struct sk_buff *skb, struct xt_action_param *par) > struct sk_buff *pskb = (struct sk_buff *)skb; > struct sock *sk = skb->sk; > > - if (!net_eq(xt_net(par), sock_net(sk))) > + if (sk && !net_eq(xt_net(par), sock_net(sk))) > sk = NULL; > > if (!sk) > -- > 2.14.4 > ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] netfilter: check if the socket netns is correct. 2018-09-27 22:58 ` Flavio Leitner 2018-09-27 23:08 ` Guenter Roeck @ 2018-09-28 8:33 ` Pablo Neira Ayuso 1 sibling, 0 replies; 4+ messages in thread From: Pablo Neira Ayuso @ 2018-09-28 8:33 UTC (permalink / raw) To: Flavio Leitner Cc: Guenter Roeck, Jozsef Kadlecsik, Florian Westphal, David S. Miller, Alexey Kuznetsov, Hideaki YOSHIFUJI, netfilter-devel, coreteam, netdev, linux-kernel On Thu, Sep 27, 2018 at 07:58:24PM -0300, Flavio Leitner wrote: [...] > From a5f927e7f1368d753f87cb978d630d786d5adb62 Mon Sep 17 00:00:00 2001 > From: Flavio Leitner <fbl@redhat.com> > Date: Thu, 27 Sep 2018 19:36:28 -0300 > Subject: [PATCH] xt_socket: check sk before checking for netns. > > Only check for the network namespace if the socket is available. Applied. Please, Cc netfilter-devel@vger.kernel.org next time for your netfilter patches. Thanks. ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2018-09-28 14:55 UTC | newest] Thread overview: 4+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2018-09-27 20:46 [PATCH] netfilter: check if the socket netns is correct Guenter Roeck 2018-09-27 22:58 ` Flavio Leitner 2018-09-27 23:08 ` Guenter Roeck 2018-09-28 8:33 ` Pablo Neira Ayuso
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