[SECMARK]: Add new packet controls to SELinux

Add new per-packet access controls to SELinux, replacing the old
packet controls.

Packets are labeled with the iptables SECMARK and CONNSECMARK targets,
then security policy for the packets is enforced with these controls.

To allow for a smooth transition to the new controls, the old code is
still present, but not active by default.  To restore previous
behavior, the old controls may be activated at runtime by writing a
'1' to /selinux/compat_net, and also via the kernel boot parameter
selinux_compat_net.  Switching between the network control models
requires the security load_policy permission.  The old controls will
probably eventually be removed and any continued use is discouraged.

With this patch, the new secmark controls for SElinux are disabled by
default, so existing behavior is entirely preserved, and the user is
not affected at all.

It also provides a config option to enable the secmark controls by
default (which can always be overridden at boot and runtime).  It is
also noted in the kconfig help that the user will need updated
userspace if enabling secmark controls for SELinux and that they'll
probably need the SECMARK and CONNMARK targets, and conntrack protocol
helpers, although such decisions are beyond the scope of kernel
configuration.

Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 133 insertions, 109 deletions

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 41b6f5d31945..54adc9d31e92 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -80,6 +80,7 @@
 
 extern unsigned int policydb_loaded_version;
 extern int selinux_nlmsg_lookup(u16 sclass, u16 nlmsg_type, u32 *perm);
+extern int selinux_compat_net;
 
 #ifdef CONFIG_SECURITY_SELINUX_DEVELOP
 int selinux_enforcing = 0;
@@ -3216,47 +3217,17 @@ static int selinux_socket_unix_may_send(struct socket *sock,
         return 0;
 }
 
-static int selinux_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
+static int selinux_sock_rcv_skb_compat(struct sock *sk, struct sk_buff *skb,
+                struct avc_audit_data *ad, u32 sock_sid, u16 sock_class,
+                u16 family, char *addrp, int len)
 {
-        u16 family;
-        char *addrp;
-        int len, err = 0;
+        int err = 0;
         u32 netif_perm, node_perm, node_sid, if_sid, recv_perm = 0;
-        u32 sock_sid = 0;
-        u16 sock_class = 0;
-        struct socket *sock;
-        struct net_device *dev;
-        struct avc_audit_data ad;
-
-        family = sk->sk_family;
-        if (family != PF_INET && family != PF_INET6)
-                goto out;
-
-        /* Handle mapped IPv4 packets arriving via IPv6 sockets */
-        if (family == PF_INET6 && skb->protocol == htons(ETH_P_IP))
-                family = PF_INET;
-
-        read_lock_bh(&sk->sk_callback_lock);
-        sock = sk->sk_socket;
-        if (sock) {
-                struct inode *inode;
-                inode = SOCK_INODE(sock);
-                if (inode) {
-                        struct inode_security_struct *isec;
-                        isec = inode->i_security;
-                        sock_sid = isec->sid;
-                        sock_class = isec->sclass;
-                }
-        }
-        read_unlock_bh(&sk->sk_callback_lock);
-        if (!sock_sid)
-                goto out;
 
-        dev = skb->dev;
-        if (!dev)
+        if (!skb->dev)
                 goto out;
 
-        err = sel_netif_sids(dev, &if_sid, NULL);
+        err = sel_netif_sids(skb->dev, &if_sid, NULL);
         if (err)
                 goto out;
 
@@ -3279,44 +3250,88 @@ static int selinux_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
                 break;
         }
 
-        AVC_AUDIT_DATA_INIT(&ad, NET);
-        ad.u.net.netif = dev->name;
-        ad.u.net.family = family;
-
-        err = selinux_parse_skb(skb, &ad, &addrp, &len, 1);
-        if (err)
-                goto out;
-
-        err = avc_has_perm(sock_sid, if_sid, SECCLASS_NETIF, netif_perm, &ad);
+        err = avc_has_perm(sock_sid, if_sid, SECCLASS_NETIF, netif_perm, ad);
         if (err)
                 goto out;
         
-        /* Fixme: this lookup is inefficient */
         err = security_node_sid(family, addrp, len, &node_sid);
         if (err)
                 goto out;
         
-        err = avc_has_perm(sock_sid, node_sid, SECCLASS_NODE, node_perm, &ad);
+        err = avc_has_perm(sock_sid, node_sid, SECCLASS_NODE, node_perm, ad);
         if (err)
                 goto out;
 
         if (recv_perm) {
                 u32 port_sid;
 
-                /* Fixme: make this more efficient */
                 err = security_port_sid(sk->sk_family, sk->sk_type,
-                                        sk->sk_protocol, ntohs(ad.u.net.sport),
+                                        sk->sk_protocol, ntohs(ad->u.net.sport),
                                         &port_sid);
                 if (err)
                         goto out;
 
                 err = avc_has_perm(sock_sid, port_sid,
-                                   sock_class, recv_perm, &ad);
+                                   sock_class, recv_perm, ad);
         }
 
-        if (!err)
-                err = selinux_xfrm_sock_rcv_skb(sock_sid, skb);
+out:
+        return err;
+}
+
+static int selinux_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
+{
+        u16 family;
+        u16 sock_class = 0;
+        char *addrp;
+        int len, err = 0;
+        u32 sock_sid = 0;
+        struct socket *sock;
+        struct avc_audit_data ad;
+
+        family = sk->sk_family;
+        if (family != PF_INET && family != PF_INET6)
+                goto out;
+
+        /* Handle mapped IPv4 packets arriving via IPv6 sockets */
+        if (family == PF_INET6 && skb->protocol == ntohs(ETH_P_IP))
+                family = PF_INET;
+
+        read_lock_bh(&sk->sk_callback_lock);
+        sock = sk->sk_socket;
+        if (sock) {
+                struct inode *inode;
+                inode = SOCK_INODE(sock);
+                if (inode) {
+                        struct inode_security_struct *isec;
+                        isec = inode->i_security;
+                        sock_sid = isec->sid;
+                        sock_class = isec->sclass;
+                }
+        }
+        read_unlock_bh(&sk->sk_callback_lock);
+        if (!sock_sid)
+                goto out;
+
+        AVC_AUDIT_DATA_INIT(&ad, NET);
+        ad.u.net.netif = skb->dev ? skb->dev->name : "[unknown]";
+        ad.u.net.family = family;
+
+        err = selinux_parse_skb(skb, &ad, &addrp, &len, 1);
+        if (err)
+                goto out;
+
+        if (selinux_compat_net)
+                err = selinux_sock_rcv_skb_compat(sk, skb, &ad, sock_sid,
+                                                  sock_class, family,
+                                                  addrp, len);
+        else
+                err = avc_has_perm(sock_sid, skb->secmark, SECCLASS_PACKET,
+                                   PACKET__RECV, &ad);
+        if (err)
+                goto out;
 
+        err = selinux_xfrm_sock_rcv_skb(sock_sid, skb);
 out:    
         return err;
 }
@@ -3456,42 +3471,18 @@ out:
 
 #ifdef CONFIG_NETFILTER
 
-static unsigned int selinux_ip_postroute_last(unsigned int hooknum,
-                                              struct sk_buff **pskb,
-                                              const struct net_device *in,
-                                              const struct net_device *out,
-                                              int (*okfn)(struct sk_buff *),
-                                              u16 family)
+static int selinux_ip_postroute_last_compat(struct sock *sk, struct net_device *dev,
+                                            struct inode_security_struct *isec,
+                                            struct avc_audit_data *ad,
+                                            u16 family, char *addrp, int len)
 {
-        char *addrp;
-        int len, err = NF_ACCEPT;
+        int err;
         u32 netif_perm, node_perm, node_sid, if_sid, send_perm = 0;
-        struct sock *sk;
-        struct socket *sock;
-        struct inode *inode;
-        struct sk_buff *skb = *pskb;
-        struct inode_security_struct *isec;
-        struct avc_audit_data ad;
-        struct net_device *dev = (struct net_device *)out;
         
-        sk = skb->sk;
-        if (!sk)
-                goto out;
-                
-        sock = sk->sk_socket;
-        if (!sock)
-                goto out;
-                
-        inode = SOCK_INODE(sock);
-        if (!inode)
-                goto out;
-
         err = sel_netif_sids(dev, &if_sid, NULL);
         if (err)
                 goto out;
 
-        isec = inode->i_security;
-        
         switch (isec->sclass) {
         case SECCLASS_UDP_SOCKET:
                 netif_perm = NETIF__UDP_SEND;
@@ -3511,55 +3502,88 @@ static unsigned int selinux_ip_postroute_last(unsigned int hooknum,
                 break;
         }
 
-
-        AVC_AUDIT_DATA_INIT(&ad, NET);
-        ad.u.net.netif = dev->name;
-        ad.u.net.family = family;
-
-        err = selinux_parse_skb(skb, &ad, &addrp,
-                                &len, 0) ? NF_DROP : NF_ACCEPT;
-        if (err != NF_ACCEPT)
-                goto out;
-
-        err = avc_has_perm(isec->sid, if_sid, SECCLASS_NETIF,
-                           netif_perm, &ad) ? NF_DROP : NF_ACCEPT;
-        if (err != NF_ACCEPT)
+        err = avc_has_perm(isec->sid, if_sid, SECCLASS_NETIF, netif_perm, ad);
+        if (err)
                 goto out;
                 
-        /* Fixme: this lookup is inefficient */
-        err = security_node_sid(family, addrp, len,
-                                &node_sid) ? NF_DROP : NF_ACCEPT;
-        if (err != NF_ACCEPT)
+        err = security_node_sid(family, addrp, len, &node_sid);
+        if (err)
                 goto out;
         
-        err = avc_has_perm(isec->sid, node_sid, SECCLASS_NODE,
-                           node_perm, &ad) ? NF_DROP : NF_ACCEPT;
-        if (err != NF_ACCEPT)
+        err = avc_has_perm(isec->sid, node_sid, SECCLASS_NODE, node_perm, ad);
+        if (err)
                 goto out;
 
         if (send_perm) {
                 u32 port_sid;
                 
-                /* Fixme: make this more efficient */
                 err = security_port_sid(sk->sk_family,
                                         sk->sk_type,
                                         sk->sk_protocol,
-                                        ntohs(ad.u.net.dport),
-                                        &port_sid) ? NF_DROP : NF_ACCEPT;
-                if (err != NF_ACCEPT)
+                                        ntohs(ad->u.net.dport),
+                                        &port_sid);
+                if (err)
                         goto out;
 
                 err = avc_has_perm(isec->sid, port_sid, isec->sclass,
-                                   send_perm, &ad) ? NF_DROP : NF_ACCEPT;
+                                   send_perm, ad);
         }
+out:
+        return err;
+}
+
+static unsigned int selinux_ip_postroute_last(unsigned int hooknum,
+                                              struct sk_buff **pskb,
+                                              const struct net_device *in,
+                                              const struct net_device *out,
+                                              int (*okfn)(struct sk_buff *),
+                                              u16 family)
+{
+        char *addrp;
+        int len, err = 0;
+        struct sock *sk;
+        struct socket *sock;
+        struct inode *inode;
+        struct sk_buff *skb = *pskb;
+        struct inode_security_struct *isec;
+        struct avc_audit_data ad;
+        struct net_device *dev = (struct net_device *)out;
 
-        if (err != NF_ACCEPT)
+        sk = skb->sk;
+        if (!sk)
                 goto out;
 
-        err = selinux_xfrm_postroute_last(isec->sid, skb);
+        sock = sk->sk_socket;
+        if (!sock)
+                goto out;
+
+        inode = SOCK_INODE(sock);
+        if (!inode)
+                goto out;
+
+        isec = inode->i_security;
+
+        AVC_AUDIT_DATA_INIT(&ad, NET);
+        ad.u.net.netif = dev->name;
+        ad.u.net.family = family;
+
+        err = selinux_parse_skb(skb, &ad, &addrp, &len, 0);
+        if (err)
+                goto out;
+
+        if (selinux_compat_net)
+                err = selinux_ip_postroute_last_compat(sk, dev, isec, &ad,
+                                                       family, addrp, len);
+        else
+                err = avc_has_perm(isec->sid, skb->secmark, SECCLASS_PACKET,
+                                   PACKET__SEND, &ad);
 
+        if (err)
+                goto out;
+
+        err = selinux_xfrm_postroute_last(isec->sid, skb);
 out:
-        return err;
+        return err ? NF_DROP : NF_ACCEPT;
 }
 
 static unsigned int selinux_ipv4_postroute_last(unsigned int hooknum,