From c0828e50485932b7e019df377a6b0a8d1ebd3080 Mon Sep 17 00:00:00 2001 From: Paul Moore Date: Tue, 10 Dec 2013 14:58:01 -0500 Subject: selinux: process labeled IPsec TCP SYN-ACK packets properly in selinux_ip_postroute() Due to difficulty in arriving at the proper security label for TCP SYN-ACK packets in selinux_ip_postroute(), we need to check packets while/before they are undergoing XFRM transforms instead of waiting until afterwards so that we can determine the correct security label. Reported-by: Janak Desai Cc: stable@vger.kernel.org Signed-off-by: Paul Moore --- security/selinux/hooks.c | 42 +++++++++++++++++++++++++++++++++++------- 1 file changed, 35 insertions(+), 7 deletions(-) (limited to 'security') diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 8b2812312ae4..6db2e589a1f3 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -4850,22 +4850,31 @@ static unsigned int selinux_ip_postroute(struct sk_buff *skb, int ifindex, * as fast and as clean as possible. */ if (!selinux_policycap_netpeer) return selinux_ip_postroute_compat(skb, ifindex, family); + + secmark_active = selinux_secmark_enabled(); + peerlbl_active = selinux_peerlbl_enabled(); + if (!secmark_active && !peerlbl_active) + return NF_ACCEPT; + + sk = skb->sk; + #ifdef CONFIG_XFRM /* If skb->dst->xfrm is non-NULL then the packet is undergoing an IPsec * packet transformation so allow the packet to pass without any checks * since we'll have another chance to perform access control checks * when the packet is on it's final way out. * NOTE: there appear to be some IPv6 multicast cases where skb->dst - * is NULL, in this case go ahead and apply access control. */ - if (skb_dst(skb) != NULL && skb_dst(skb)->xfrm != NULL) + * is NULL, in this case go ahead and apply access control. + * NOTE: if this is a local socket (skb->sk != NULL) that is in the + * TCP listening state we cannot wait until the XFRM processing + * is done as we will miss out on the SA label if we do; + * unfortunately, this means more work, but it is only once per + * connection. */ + if (skb_dst(skb) != NULL && skb_dst(skb)->xfrm != NULL && + !(sk != NULL && sk->sk_state == TCP_LISTEN)) return NF_ACCEPT; #endif - secmark_active = selinux_secmark_enabled(); - peerlbl_active = selinux_peerlbl_enabled(); - if (!secmark_active && !peerlbl_active) - return NF_ACCEPT; - sk = skb->sk; if (sk == NULL) { /* Without an associated socket the packet is either coming * from the kernel or it is being forwarded; check the packet @@ -4893,6 +4902,25 @@ static unsigned int selinux_ip_postroute(struct sk_buff *skb, int ifindex, struct sk_security_struct *sksec = sk->sk_security; if (selinux_skb_peerlbl_sid(skb, family, &skb_sid)) return NF_DROP; + /* At this point, if the returned skb peerlbl is SECSID_NULL + * and the packet has been through at least one XFRM + * transformation then we must be dealing with the "final" + * form of labeled IPsec packet; since we've already applied + * all of our access controls on this packet we can safely + * pass the packet. */ + if (skb_sid == SECSID_NULL) { + switch (family) { + case PF_INET: + if (IPCB(skb)->flags & IPSKB_XFRM_TRANSFORMED) + return NF_ACCEPT; + break; + case PF_INET6: + if (IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED) + return NF_ACCEPT; + default: + return NF_DROP_ERR(-ECONNREFUSED); + } + } if (selinux_conn_sid(sksec->sid, skb_sid, &peer_sid)) return NF_DROP; secmark_perm = PACKET__SEND; -- cgit v1.2.3-59-g8ed1b