From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: [PATCH] ipv4: tcp: unicast_sock should not land outside of TCP stack Date: Fri, 10 Aug 2012 01:56:06 +0200 Message-ID: <1344556566.31104.808.camel@edumazet-glaptop> References: <1344523833.28967.996.camel@edumazet-glaptop> <1344547743.31104.582.camel@edumazet-glaptop> <20120809.163851.1182547052663187702.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: eparis@parisplace.org, paul@paul-moore.com, casey@schaufler-ca.com, johnstul@us.ibm.com, serge@hallyn.com, linux-kernel@vger.kernel.org, james.l.morris@oracle.com, selinux@tycho.nsa.gov, john.johansen@canonical.com, linux-security-module@vger.kernel.org, netdev@vger.kernel.org To: David Miller Return-path: In-Reply-To: <20120809.163851.1182547052663187702.davem@davemloft.net> Sender: linux-security-module-owner@vger.kernel.org List-Id: netdev.vger.kernel.org From: Eric Dumazet commit be9f4a44e7d41cee (ipv4: tcp: remove per net tcp_sock) added a selinux regression, reported and bisected by John Stultz selinux_ip_postroute_compat() expect to find a valid sk->sk_security pointer, but this field is NULL for unicast_sock It turns out that unicast_sock are really temporary stuff to be able to reuse part of IP stack (ip_append_data()/ip_push_pending_frames()) Fact is that frames sent by ip_send_unicast_reply() should be orphaned to not fool LSM. Note IPv6 never had this problem, as tcp_v6_send_response() doesnt use a fake socket at all. I'll probably implement tcp_v4_send_response() to remove these unicast_sock in linux-3.7 Reported-by: John Stultz Bisected-by: John Stultz Signed-off-by: Eric Dumazet Cc: Paul Moore Cc: Eric Paris Cc: "Serge E. Hallyn" --- net/ipv4/ip_output.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index 76dde25..ec410e0 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -1536,6 +1536,7 @@ void ip_send_unicast_reply(struct net *net, struct sk_buff *skb, __be32 daddr, arg->csumoffset) = csum_fold(csum_add(nskb->csum, arg->csum)); nskb->ip_summed = CHECKSUM_NONE; + skb_orphan(nskb); skb_set_queue_mapping(nskb, skb_get_queue_mapping(skb)); ip_push_pending_frames(sk, &fl4); }