selinux: Fix packet forwarding checks on postrouting (4a7ab3dc) · Commits · 戴 / test

The IPSKB_FORWARDED and IP6SKB_FORWARDED flags are used only in the multicast forwarding case to indicate that a packet looped back after forward. So these flags are not a good indicator for packet forwarding. A better indicator is the incoming interface. If we have no socket context, but an incoming interface and we see the packet in the ip postroute hook, the packet is going to be forwarded. With this patch we use the incoming interface as an indicator on packet forwarding. Signed-off-by:

Steffen Klassert <steffen.klassert@secunet.com> Acked-by:

Paul Moore <paul.moore@hp.com> Signed-off-by:

Eric Paris <eparis@redhat.com>

security/selinux/hooks.c

+5 −18

Original line number	Diff line number	Diff line
		@@ -4475,27 +4475,14 @@ static unsigned int selinux_ip_postroute(struct sk_buff *skb, int ifindex,
		* from the sending socket, otherwise use the kernel's sid */
		sk = skb->sk;
		if (sk == NULL) {
		switch (family) {
		case PF_INET:
		if (IPCB(skb)->flags & IPSKB_FORWARDED)
		if (skb->skb_iif) {
		secmark_perm = PACKET__FORWARD_OUT;
		else
		secmark_perm = PACKET__SEND;
		break;
		case PF_INET6:
		if (IP6CB(skb)->flags & IP6SKB_FORWARDED)
		secmark_perm = PACKET__FORWARD_OUT;
		else
		secmark_perm = PACKET__SEND;
		break;
		default:
		return NF_DROP_ERR(-ECONNREFUSED);
		}
		if (secmark_perm == PACKET__FORWARD_OUT) {
		if (selinux_skb_peerlbl_sid(skb, family, &peer_sid))
		return NF_DROP;
		} else
		} else {
		secmark_perm = PACKET__SEND;
		peer_sid = SECINITSID_KERNEL;
		}
		} else {
		struct sk_security_struct *sksec = sk->sk_security;
		peer_sid = sksec->sid;

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