4 files changed, 83 insertions, 7 deletions

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 42b6c6319bc2..87214a257d2a 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -130,17 +130,10 @@ static inline struct tun_sock *tun_sk(struct sock *sk)
 static int tun_attach(struct tun_struct *tun, struct file *file)
 {
         struct tun_file *tfile = file->private_data;
-        const struct cred *cred = current_cred();
         int err;
 
         ASSERT_RTNL();
 
-        /* Check permissions */
-        if (((tun->owner != -1 && cred->euid != tun->owner) ||
-             (tun->group != -1 && !in_egroup_p(tun->group))) &&
-                !capable(CAP_NET_ADMIN))
-                return -EPERM;
-
         netif_tx_lock_bh(tun->dev);
 
         err = -EINVAL;
@@ -926,6 +919,8 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
 
         dev = __dev_get_by_name(net, ifr->ifr_name);
         if (dev) {
+                const struct cred *cred = current_cred();
+
                 if (ifr->ifr_flags & IFF_TUN_EXCL)
                         return -EBUSY;
                 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
@@ -935,6 +930,14 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
                 else
                         return -EINVAL;
 
+                if (((tun->owner != -1 && cred->euid != tun->owner) ||
+                     (tun->group != -1 && !in_egroup_p(tun->group))) &&
+                    !capable(CAP_NET_ADMIN))
+                        return -EPERM;
+                err = security_tun_dev_attach(tun->sk);
+                if (err < 0)
+                        return err;
+
                 err = tun_attach(tun, file);
                 if (err < 0)
                         return err;
@@ -947,6 +950,9 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
 
                 if (!capable(CAP_NET_ADMIN))
                         return -EPERM;
+                err = security_tun_dev_create();
+                if (err < 0)
+                        return err;
 
                 /* Set dev type */
                 if (ifr->ifr_flags & IFF_TUN) {
@@ -989,6 +995,8 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
                 tun->sk = sk;
                 container_of(sk, struct tun_sock, sk)->tun = tun;
 
+                security_tun_dev_post_create(sk);
+
                 tun_net_init(dev);
 
                 if (strchr(dev->name, '%')) {
diff --git a/include/linux/security.h b/include/linux/security.h
index a16d6b7c4ebe..40ba39ea68ce 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -998,6 +998,17 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts)
  *      Sets the connection's peersid to the secmark on skb.
  * @req_classify_flow:
  *      Sets the flow's sid to the openreq sid.
+ * @tun_dev_create:
+ *      Check permissions prior to creating a new TUN device.
+ * @tun_dev_post_create:
+ *      This hook allows a module to update or allocate a per-socket security
+ *      structure.
+ *      @sk contains the newly created sock structure.
+ * @tun_dev_attach:
+ *      Check permissions prior to attaching to a persistent TUN device.  This
+ *      hook can also be used by the module to update any security state
+ *      associated with the TUN device's sock structure.
+ *      @sk contains the existing sock structure.
  *
  * Security hooks for XFRM operations.
  *
@@ -1597,6 +1608,9 @@ struct security_operations {
         void (*inet_csk_clone) (struct sock *newsk, const struct request_sock *req);
         void (*inet_conn_established) (struct sock *sk, struct sk_buff *skb);
         void (*req_classify_flow) (const struct request_sock *req, struct flowi *fl);
+        int (*tun_dev_create)(void);
+        void (*tun_dev_post_create)(struct sock *sk);
+        int (*tun_dev_attach)(struct sock *sk);
 #endif  /* CONFIG_SECURITY_NETWORK */
 
 #ifdef CONFIG_SECURITY_NETWORK_XFRM
@@ -2586,6 +2600,9 @@ void security_inet_csk_clone(struct sock *newsk,
                         const struct request_sock *req);
 void security_inet_conn_established(struct sock *sk,
                         struct sk_buff *skb);
+int security_tun_dev_create(void);
+void security_tun_dev_post_create(struct sock *sk);
+int security_tun_dev_attach(struct sock *sk);
 
 #else   /* CONFIG_SECURITY_NETWORK */
 static inline int security_unix_stream_connect(struct socket *sock,
@@ -2736,6 +2753,20 @@ static inline void security_inet_conn_established(struct sock *sk,
                         struct sk_buff *skb)
 {
 }
+
+static inline int security_tun_dev_create(void)
+{
+        return 0;
+}
+
+static inline void security_tun_dev_post_create(struct sock *sk)
+{
+}
+
+static inline int security_tun_dev_attach(struct sock *sk)
+{
+        return 0;
+}
 #endif  /* CONFIG_SECURITY_NETWORK */
 
 #ifdef CONFIG_SECURITY_NETWORK_XFRM
diff --git a/security/capability.c b/security/capability.c
index 1b943f54b2ea..06400cf07757 100644
--- a/security/capability.c
+++ b/security/capability.c
@@ -706,10 +706,26 @@ static void cap_inet_conn_established(struct sock *sk, struct sk_buff *skb)
 {
 }
 
+
+
 static void cap_req_classify_flow(const struct request_sock *req,
                                   struct flowi *fl)
 {
 }
+
+static int cap_tun_dev_create(void)
+{
+        return 0;
+}
+
+static void cap_tun_dev_post_create(struct sock *sk)
+{
+}
+
+static int cap_tun_dev_attach(struct sock *sk)
+{
+        return 0;
+}
 #endif  /* CONFIG_SECURITY_NETWORK */
 
 #ifdef CONFIG_SECURITY_NETWORK_XFRM
@@ -1026,6 +1042,9 @@ void security_fixup_ops(struct security_operations *ops)
         set_to_cap_if_null(ops, inet_csk_clone);
         set_to_cap_if_null(ops, inet_conn_established);
         set_to_cap_if_null(ops, req_classify_flow);
+        set_to_cap_if_null(ops, tun_dev_create);
+        set_to_cap_if_null(ops, tun_dev_post_create);
+        set_to_cap_if_null(ops, tun_dev_attach);
 #endif  /* CONFIG_SECURITY_NETWORK */
 #ifdef CONFIG_SECURITY_NETWORK_XFRM
         set_to_cap_if_null(ops, xfrm_policy_alloc_security);
diff --git a/security/security.c b/security/security.c
index 0e993f42ce3d..f88eaf6b14cc 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1117,6 +1117,24 @@ void security_inet_conn_established(struct sock *sk,
         security_ops->inet_conn_established(sk, skb);
 }
 
+int security_tun_dev_create(void)
+{
+        return security_ops->tun_dev_create();
+}
+EXPORT_SYMBOL(security_tun_dev_create);
+
+void security_tun_dev_post_create(struct sock *sk)
+{
+        return security_ops->tun_dev_post_create(sk);
+}
+EXPORT_SYMBOL(security_tun_dev_post_create);
+
+int security_tun_dev_attach(struct sock *sk)
+{
+        return security_ops->tun_dev_attach(sk);
+}
+EXPORT_SYMBOL(security_tun_dev_attach);
+
 #endif  /* CONFIG_SECURITY_NETWORK */
 
 #ifdef CONFIG_SECURITY_NETWORK_XFRM