* [PATCH 1/1] netfilter: ctnetlink: don't permit ct creation with random tuple
@ 2013-02-12 9:22 Florian Westphal
2013-02-12 12:24 ` Pablo Neira Ayuso
2013-02-12 22:35 ` Pablo Neira Ayuso
0 siblings, 2 replies; 5+ messages in thread
From: Florian Westphal @ 2013-02-12 9:22 UTC (permalink / raw)
To: netfilter-devel; +Cc: Florian Westphal
Userspace can cause kernel panic by not specifying orig/reply
tuple: kernel will create a tuple with random stack values.
Problem is that tuple.dst.dir will be random, too, which
causes nf_ct_tuplehash_to_ctrack() to return garbage.
Signed-off-by: Florian Westphal <fw@strlen.de>
---
net/netfilter/nf_conntrack_netlink.c | 3 +++
1 files changed, 3 insertions(+), 0 deletions(-)
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index 7bbfb3d..e592281 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -1596,6 +1596,9 @@ ctnetlink_new_conntrack(struct sock *ctnl, struct sk_buff *skb,
if (nlh->nlmsg_flags & NLM_F_CREATE) {
enum ip_conntrack_events events;
+ if (!cda[CTA_TUPLE_ORIG] ||
+ !cda[CTA_TUPLE_REPLY])
+ return -EINVAL;
ct = ctnetlink_create_conntrack(net, zone, cda, &otuple,
&rtuple, u3);
if (IS_ERR(ct))
--
1.7.8.6
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH 1/1] netfilter: ctnetlink: don't permit ct creation with random tuple
2013-02-12 9:22 [PATCH 1/1] netfilter: ctnetlink: don't permit ct creation with random tuple Florian Westphal
@ 2013-02-12 12:24 ` Pablo Neira Ayuso
2013-02-12 12:43 ` Florian Westphal
2013-02-12 22:35 ` Pablo Neira Ayuso
1 sibling, 1 reply; 5+ messages in thread
From: Pablo Neira Ayuso @ 2013-02-12 12:24 UTC (permalink / raw)
To: Florian Westphal; +Cc: netfilter-devel
On Tue, Feb 12, 2013 at 10:22:38AM +0100, Florian Westphal wrote:
> Userspace can cause kernel panic by not specifying orig/reply
> tuple: kernel will create a tuple with random stack values.
>
> Problem is that tuple.dst.dir will be random, too, which
> causes nf_ct_tuplehash_to_ctrack() to return garbage.
good catch.
> Signed-off-by: Florian Westphal <fw@strlen.de>
> ---
> net/netfilter/nf_conntrack_netlink.c | 3 +++
> 1 files changed, 3 insertions(+), 0 deletions(-)
>
> diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
> index 7bbfb3d..e592281 100644
> --- a/net/netfilter/nf_conntrack_netlink.c
> +++ b/net/netfilter/nf_conntrack_netlink.c
> @@ -1596,6 +1596,9 @@ ctnetlink_new_conntrack(struct sock *ctnl, struct sk_buff *skb,
> if (nlh->nlmsg_flags & NLM_F_CREATE) {
> enum ip_conntrack_events events;
>
> + if (!cda[CTA_TUPLE_ORIG] ||
> + !cda[CTA_TUPLE_REPLY])
> + return -EINVAL;
I think that needs to be && instead of ||.
No need to resend the patch, I'll fix it and apply.
Thanks Florian.
> ct = ctnetlink_create_conntrack(net, zone, cda, &otuple,
> &rtuple, u3);
> if (IS_ERR(ct))
> --
> 1.7.8.6
>
> --
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> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH 1/1] netfilter: ctnetlink: don't permit ct creation with random tuple
2013-02-12 12:24 ` Pablo Neira Ayuso
@ 2013-02-12 12:43 ` Florian Westphal
2013-02-12 13:10 ` Pablo Neira Ayuso
0 siblings, 1 reply; 5+ messages in thread
From: Florian Westphal @ 2013-02-12 12:43 UTC (permalink / raw)
To: Pablo Neira Ayuso; +Cc: Florian Westphal, netfilter-devel
Pablo Neira Ayuso <pablo@netfilter.org> wrote:
> On Tue, Feb 12, 2013 at 10:22:38AM +0100, Florian Westphal wrote:
> > Userspace can cause kernel panic by not specifying orig/reply
> > tuple: kernel will create a tuple with random stack values.
> >
> > Problem is that tuple.dst.dir will be random, too, which
> > causes nf_ct_tuplehash_to_ctrack() to return garbage.
[..]
> > diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
> > index 7bbfb3d..e592281 100644
> > --- a/net/netfilter/nf_conntrack_netlink.c
> > +++ b/net/netfilter/nf_conntrack_netlink.c
> > @@ -1596,6 +1596,9 @@ ctnetlink_new_conntrack(struct sock *ctnl, struct sk_buff *skb,
> > if (nlh->nlmsg_flags & NLM_F_CREATE) {
> > enum ip_conntrack_events events;
> >
> > + if (!cda[CTA_TUPLE_ORIG] ||
> > + !cda[CTA_TUPLE_REPLY])
> > + return -EINVAL;
>
> I think that needs to be && instead of ||.
Uh, maybe I'm too low on caffeine, but when a new conntrack
is to be created, shouldn't userspace have to specify
_both_ ORIG and REPLY?
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH 1/1] netfilter: ctnetlink: don't permit ct creation with random tuple
2013-02-12 12:43 ` Florian Westphal
@ 2013-02-12 13:10 ` Pablo Neira Ayuso
0 siblings, 0 replies; 5+ messages in thread
From: Pablo Neira Ayuso @ 2013-02-12 13:10 UTC (permalink / raw)
To: Florian Westphal; +Cc: netfilter-devel
On Tue, Feb 12, 2013 at 01:43:28PM +0100, Florian Westphal wrote:
> Pablo Neira Ayuso <pablo@netfilter.org> wrote:
> > On Tue, Feb 12, 2013 at 10:22:38AM +0100, Florian Westphal wrote:
> > > Userspace can cause kernel panic by not specifying orig/reply
> > > tuple: kernel will create a tuple with random stack values.
> > >
> > > Problem is that tuple.dst.dir will be random, too, which
> > > causes nf_ct_tuplehash_to_ctrack() to return garbage.
>
> [..]
>
> > > diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
> > > index 7bbfb3d..e592281 100644
> > > --- a/net/netfilter/nf_conntrack_netlink.c
> > > +++ b/net/netfilter/nf_conntrack_netlink.c
> > > @@ -1596,6 +1596,9 @@ ctnetlink_new_conntrack(struct sock *ctnl, struct sk_buff *skb,
> > > if (nlh->nlmsg_flags & NLM_F_CREATE) {
> > > enum ip_conntrack_events events;
> > >
> > > + if (!cda[CTA_TUPLE_ORIG] ||
> > > + !cda[CTA_TUPLE_REPLY])
> > > + return -EINVAL;
> >
> > I think that needs to be && instead of ||.
>
> Uh, maybe I'm too low on caffeine, but when a new conntrack
> is to be created, shouldn't userspace have to specify
> _both_ ORIG and REPLY?
You're right, it's me who is low on caffeine. Sorry.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 1/1] netfilter: ctnetlink: don't permit ct creation with random tuple
2013-02-12 9:22 [PATCH 1/1] netfilter: ctnetlink: don't permit ct creation with random tuple Florian Westphal
2013-02-12 12:24 ` Pablo Neira Ayuso
@ 2013-02-12 22:35 ` Pablo Neira Ayuso
1 sibling, 0 replies; 5+ messages in thread
From: Pablo Neira Ayuso @ 2013-02-12 22:35 UTC (permalink / raw)
To: Florian Westphal; +Cc: netfilter-devel
On Tue, Feb 12, 2013 at 10:22:38AM +0100, Florian Westphal wrote:
> Userspace can cause kernel panic by not specifying orig/reply
> tuple: kernel will create a tuple with random stack values.
>
> Problem is that tuple.dst.dir will be random, too, which
> causes nf_ct_tuplehash_to_ctrack() to return garbage.
Applied, thanks Florian.
^ permalink raw reply [flat|nested] 5+ messages in thread
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2013-02-12 9:22 [PATCH 1/1] netfilter: ctnetlink: don't permit ct creation with random tuple Florian Westphal
2013-02-12 12:24 ` Pablo Neira Ayuso
2013-02-12 12:43 ` Florian Westphal
2013-02-12 13:10 ` Pablo Neira Ayuso
2013-02-12 22:35 ` Pablo Neira Ayuso
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