selinux: make better use of the nf_hook_state passed to the NF hooks

This patch builds on a previous SELinux/netfilter patch by Florian
Westphal and makes better use of the nf_hook_state variable passed
into the SELinux/netfilter hooks as well as a number of other small
cleanups in the related code.

Signed-off-by: Paul Moore <[email protected]>

Author: pcmoore

security/selinux/hooks.c

@@ -5692,38 +5692,38 @@ static int selinux_tun_dev_open(void *security)
 static unsigned int selinux_ip_forward(void *priv, struct sk_buff *skb,
 				       const struct nf_hook_state *state)
 {
-	const struct net_device *indev = state->in;
-	u16 family = state->pf;
-	int err;
+	int ifindex;
+	u16 family;
 	char *addrp;
 	u32 peer_sid;
 	struct common_audit_data ad;
 	struct lsm_network_audit net = {0,};
-	u8 secmark_active;
-	u8 netlbl_active;
-	u8 peerlbl_active;
+	int secmark_active, peerlbl_active;
 
 	if (!selinux_policycap_netpeer())
 		return NF_ACCEPT;
 
 	secmark_active = selinux_secmark_enabled();
-	netlbl_active = netlbl_enabled();
 	peerlbl_active = selinux_peerlbl_enabled();
 	if (!secmark_active && !peerlbl_active)
 		return NF_ACCEPT;
 
+	family = state->pf;
 	if (selinux_skb_peerlbl_sid(skb, family, &peer_sid) != 0)
 		return NF_DROP;
 
+	ifindex = state->in->ifindex;
 	ad.type = LSM_AUDIT_DATA_NET;
 	ad.u.net = &net;
-	ad.u.net->netif = indev->ifindex;
+	ad.u.net->netif = ifindex;
 	ad.u.net->family = family;
 	if (selinux_parse_skb(skb, &ad, &addrp, 1, NULL) != 0)
 		return NF_DROP;
 
 	if (peerlbl_active) {
-		err = selinux_inet_sys_rcv_skb(dev_net(indev), indev->ifindex,
+		int err;
+
+		err = selinux_inet_sys_rcv_skb(state->net, ifindex,
 					       addrp, family, peer_sid, &ad);
 		if (err) {
 			selinux_netlbl_err(skb, family, err, 1);
@@ -5737,7 +5737,7 @@ static unsigned int selinux_ip_forward(void *priv, struct sk_buff *skb,
 				 SECCLASS_PACKET, PACKET__FORWARD_IN, &ad))
 			return NF_DROP;
 
-	if (netlbl_active)
+	if (netlbl_enabled())
 		/* we do this in the FORWARD path and not the POST_ROUTING
 		 * path because we want to make sure we apply the necessary
 		 * labeling before IPsec is applied so we can leverage AH
@@ -5751,7 +5751,6 @@ static unsigned int selinux_ip_forward(void *priv, struct sk_buff *skb,
 static unsigned int selinux_ip_output(void *priv, struct sk_buff *skb,
 				      const struct nf_hook_state *state)
 {
-	u16 family = state->pf;
 	struct sock *sk;
 	u32 sid;
 
@@ -5785,33 +5784,32 @@ static unsigned int selinux_ip_output(void *priv, struct sk_buff *skb,
 		sid = sksec->sid;
 	} else
 		sid = SECINITSID_KERNEL;
-	if (selinux_netlbl_skbuff_setsid(skb, family, sid) != 0)
+	if (selinux_netlbl_skbuff_setsid(skb, state->pf, sid) != 0)
 		return NF_DROP;
 
 	return NF_ACCEPT;
 }
 
 
 static unsigned int selinux_ip_postroute_compat(struct sk_buff *skb,
-						int ifindex,
-						u16 family)
+					const struct nf_hook_state *state)
 {
-	struct sock *sk = skb_to_full_sk(skb);
+	struct sock *sk;
 	struct sk_security_struct *sksec;
 	struct common_audit_data ad;
 	struct lsm_network_audit net = {0,};
-	char *addrp;
 	u8 proto;
 
-	if (sk == NULL)
+	if (state->sk == NULL)
 		return NF_ACCEPT;
+	sk = skb_to_full_sk(skb);
 	sksec = sk->sk_security;
 
 	ad.type = LSM_AUDIT_DATA_NET;
 	ad.u.net = &net;
-	ad.u.net->netif = ifindex;
-	ad.u.net->family = family;
-	if (selinux_parse_skb(skb, &ad, &addrp, 0, &proto))
+	ad.u.net->netif = state->out->ifindex;
+	ad.u.net->family = state->pf;
+	if (selinux_parse_skb(skb, &ad, NULL, 0, &proto))
 		return NF_DROP;
 
 	if (selinux_secmark_enabled())
@@ -5830,24 +5828,22 @@ static unsigned int selinux_ip_postroute(void *priv,
 					 struct sk_buff *skb,
 					 const struct nf_hook_state *state)
 {
-	const struct net_device *outdev = state->out;
-	u16 family = state->pf;
+	u16 family;
 	u32 secmark_perm;
 	u32 peer_sid;
-	int ifindex = outdev->ifindex;
+	int ifindex;
 	struct sock *sk;
 	struct common_audit_data ad;
 	struct lsm_network_audit net = {0,};
 	char *addrp;
-	u8 secmark_active;
-	u8 peerlbl_active;
+	int secmark_active, peerlbl_active;
 
 	/* If any sort of compatibility mode is enabled then handoff processing
 	 * to the selinux_ip_postroute_compat() function to deal with the
 	 * special handling.  We do this in an attempt to keep this function
 	 * as fast and as clean as possible. */
 	if (!selinux_policycap_netpeer())
-		return selinux_ip_postroute_compat(skb, ifindex, family);
+		return selinux_ip_postroute_compat(skb, state);
 
 	secmark_active = selinux_secmark_enabled();
 	peerlbl_active = selinux_peerlbl_enabled();
@@ -5873,6 +5869,7 @@ static unsigned int selinux_ip_postroute(void *priv,
 		return NF_ACCEPT;
 #endif
 
+	family = state->pf;
 	if (sk == NULL) {
 		/* Without an associated socket the packet is either coming
 		 * from the kernel or it is being forwarded; check the packet
@@ -5933,6 +5930,7 @@ static unsigned int selinux_ip_postroute(void *priv,
 		secmark_perm = PACKET__SEND;
 	}
 
+	ifindex = state->out->ifindex;
 	ad.type = LSM_AUDIT_DATA_NET;
 	ad.u.net = &net;
 	ad.u.net->netif = ifindex;
@@ -5950,7 +5948,7 @@ static unsigned int selinux_ip_postroute(void *priv,
 		u32 if_sid;
 		u32 node_sid;
 
-		if (sel_netif_sid(dev_net(outdev), ifindex, &if_sid))
+		if (sel_netif_sid(state->net, ifindex, &if_sid))
 			return NF_DROP;
 		if (avc_has_perm(&selinux_state,
 				 peer_sid, if_sid,