Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security

Pull SELinux fixes from James Morris.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  selinux: process labeled IPsec TCP SYN-ACK packets properly in selinux_ip_postroute()
  selinux: look for IPsec labels on both inbound and outbound packets
  selinux: handle TCP SYN-ACK packets correctly in selinux_ip_postroute()
  selinux: handle TCP SYN-ACK packets correctly in selinux_ip_output()
  selinux: fix possible memory leak

3 files changed, 165 insertions, 42 deletions

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 98b1caa1c1d3..419491d8e7d2 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -53,6 +53,7 @@
 #include <net/ip.h>             /* for local_port_range[] */
 #include <net/sock.h>
 #include <net/tcp.h>            /* struct or_callable used in sock_rcv_skb */
+#include <net/inet_connection_sock.h>
 #include <net/net_namespace.h>
 #include <net/netlabel.h>
 #include <linux/uaccess.h>
@@ -3824,7 +3825,7 @@ static int selinux_skb_peerlbl_sid(struct sk_buff *skb, u16 family, u32 *sid)
         u32 nlbl_sid;
         u32 nlbl_type;
 
-        err = selinux_skb_xfrm_sid(skb, &xfrm_sid);
+        err = selinux_xfrm_skb_sid(skb, &xfrm_sid);
         if (unlikely(err))
                 return -EACCES;
         err = selinux_netlbl_skbuff_getsid(skb, family, &nlbl_type, &nlbl_sid);
@@ -3842,6 +3843,30 @@ static int selinux_skb_peerlbl_sid(struct sk_buff *skb, u16 family, u32 *sid)
         return 0;
 }
 
+/**
+ * selinux_conn_sid - Determine the child socket label for a connection
+ * @sk_sid: the parent socket's SID
+ * @skb_sid: the packet's SID
+ * @conn_sid: the resulting connection SID
+ *
+ * If @skb_sid is valid then the user:role:type information from @sk_sid is
+ * combined with the MLS information from @skb_sid in order to create
+ * @conn_sid.  If @skb_sid is not valid then then @conn_sid is simply a copy
+ * of @sk_sid.  Returns zero on success, negative values on failure.
+ *
+ */
+static int selinux_conn_sid(u32 sk_sid, u32 skb_sid, u32 *conn_sid)
+{
+        int err = 0;
+
+        if (skb_sid != SECSID_NULL)
+                err = security_sid_mls_copy(sk_sid, skb_sid, conn_sid);
+        else
+                *conn_sid = sk_sid;
+
+        return err;
+}
+
 /* socket security operations */
 
 static int socket_sockcreate_sid(const struct task_security_struct *tsec,
@@ -4448,7 +4473,7 @@ static int selinux_inet_conn_request(struct sock *sk, struct sk_buff *skb,
         struct sk_security_struct *sksec = sk->sk_security;
         int err;
         u16 family = sk->sk_family;
-        u32 newsid;
+        u32 connsid;
         u32 peersid;
 
         /* handle mapped IPv4 packets arriving via IPv6 sockets */
@@ -4458,16 +4483,11 @@ static int selinux_inet_conn_request(struct sock *sk, struct sk_buff *skb,
         err = selinux_skb_peerlbl_sid(skb, family, &peersid);
         if (err)
                 return err;
-        if (peersid == SECSID_NULL) {
-                req->secid = sksec->sid;
-                req->peer_secid = SECSID_NULL;
-        } else {
-                err = security_sid_mls_copy(sksec->sid, peersid, &newsid);
-                if (err)
-                        return err;
-                req->secid = newsid;
-                req->peer_secid = peersid;
-        }
+        err = selinux_conn_sid(sksec->sid, peersid, &connsid);
+        if (err)
+                return err;
+        req->secid = connsid;
+        req->peer_secid = peersid;
 
         return selinux_netlbl_inet_conn_request(req, family);
 }
@@ -4727,6 +4747,7 @@ static unsigned int selinux_ipv6_forward(const struct nf_hook_ops *ops,
 static unsigned int selinux_ip_output(struct sk_buff *skb,
                                       u16 family)
 {
+        struct sock *sk;
         u32 sid;
 
         if (!netlbl_enabled())
@@ -4735,8 +4756,27 @@ static unsigned int selinux_ip_output(struct sk_buff *skb,
         /* we do this in the LOCAL_OUT 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 protection */
-        if (skb->sk) {
-                struct sk_security_struct *sksec = skb->sk->sk_security;
+        sk = skb->sk;
+        if (sk) {
+                struct sk_security_struct *sksec;
+
+                if (sk->sk_state == TCP_LISTEN)
+                        /* if the socket is the listening state then this
+                         * packet is a SYN-ACK packet which means it needs to
+                         * be labeled based on the connection/request_sock and
+                         * not the parent socket.  unfortunately, we can't
+                         * lookup the request_sock yet as it isn't queued on
+                         * the parent socket until after the SYN-ACK is sent.
+                         * the "solution" is to simply pass the packet as-is
+                         * as any IP option based labeling should be copied
+                         * from the initial connection request (in the IP
+                         * layer).  it is far from ideal, but until we get a
+                         * security label in the packet itself this is the
+                         * best we can do. */
+                        return NF_ACCEPT;
+
+                /* standard practice, label using the parent socket */
+                sksec = sk->sk_security;
                 sid = sksec->sid;
         } else
                 sid = SECINITSID_KERNEL;
@@ -4806,27 +4846,36 @@ 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;
 
-        /* if the packet is being forwarded then get the peer label from the
-         * packet itself; otherwise check to see if it is from a local
-         * application or the kernel, if from an application get the peer label
-         * from the sending socket, otherwise use the kernel's sid */
-        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
+                 * to determine which and if the packet is being forwarded
+                 * query the packet directly to determine the security label. */
                 if (skb->skb_iif) {
                         secmark_perm = PACKET__FORWARD_OUT;
                         if (selinux_skb_peerlbl_sid(skb, family, &peer_sid))
@@ -4835,7 +4884,45 @@ static unsigned int selinux_ip_postroute(struct sk_buff *skb, int ifindex,
                         secmark_perm = PACKET__SEND;
                         peer_sid = SECINITSID_KERNEL;
                 }
+        } else if (sk->sk_state == TCP_LISTEN) {
+                /* Locally generated packet but the associated socket is in the
+                 * listening state which means this is a SYN-ACK packet.  In
+                 * this particular case the correct security label is assigned
+                 * to the connection/request_sock but unfortunately we can't
+                 * query the request_sock as it isn't queued on the parent
+                 * socket until after the SYN-ACK packet is sent; the only
+                 * viable choice is to regenerate the label like we do in
+                 * selinux_inet_conn_request().  See also selinux_ip_output()
+                 * for similar problems. */
+                u32 skb_sid;
+                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;
         } else {
+                /* Locally generated packet, fetch the security label from the
+                 * associated socket. */
                 struct sk_security_struct *sksec = sk->sk_security;
                 peer_sid = sksec->sid;
                 secmark_perm = PACKET__SEND;
diff --git a/security/selinux/include/xfrm.h b/security/selinux/include/xfrm.h
index 0dec76c64cf5..48c3cc94c168 100644
--- a/security/selinux/include/xfrm.h
+++ b/security/selinux/include/xfrm.h
@@ -39,6 +39,7 @@ int selinux_xfrm_sock_rcv_skb(u32 sk_sid, struct sk_buff *skb,
 int selinux_xfrm_postroute_last(u32 sk_sid, struct sk_buff *skb,
                                 struct common_audit_data *ad, u8 proto);
 int selinux_xfrm_decode_session(struct sk_buff *skb, u32 *sid, int ckall);
+int selinux_xfrm_skb_sid(struct sk_buff *skb, u32 *sid);
 
 static inline void selinux_xfrm_notify_policyload(void)
 {
@@ -79,11 +80,12 @@ static inline int selinux_xfrm_decode_session(struct sk_buff *skb, u32 *sid,
 static inline void selinux_xfrm_notify_policyload(void)
 {
 }
-#endif
 
-static inline int selinux_skb_xfrm_sid(struct sk_buff *skb, u32 *sid)
+static inline int selinux_xfrm_skb_sid(struct sk_buff *skb, u32 *sid)
 {
-        return selinux_xfrm_decode_session(skb, sid, 0);
+        *sid = SECSID_NULL;
+        return 0;
 }
+#endif
 
 #endif /* _SELINUX_XFRM_H_ */
diff --git a/security/selinux/xfrm.c b/security/selinux/xfrm.c
index a91d205ec0c6..0462cb3ff0a7 100644
--- a/security/selinux/xfrm.c
+++ b/security/selinux/xfrm.c
@@ -209,19 +209,26 @@ int selinux_xfrm_state_pol_flow_match(struct xfrm_state *x,
                             NULL) ? 0 : 1);
 }
 
-/*
- * LSM hook implementation that checks and/or returns the xfrm sid for the
- * incoming packet.
- */
-int selinux_xfrm_decode_session(struct sk_buff *skb, u32 *sid, int ckall)
+static u32 selinux_xfrm_skb_sid_egress(struct sk_buff *skb)
 {
-        u32 sid_session = SECSID_NULL;
-        struct sec_path *sp;
+        struct dst_entry *dst = skb_dst(skb);
+        struct xfrm_state *x;
 
-        if (skb == NULL)
-                goto out;
+        if (dst == NULL)
+                return SECSID_NULL;
+        x = dst->xfrm;
+        if (x == NULL || !selinux_authorizable_xfrm(x))
+                return SECSID_NULL;
+
+        return x->security->ctx_sid;
+}
+
+static int selinux_xfrm_skb_sid_ingress(struct sk_buff *skb,
+                                        u32 *sid, int ckall)
+{
+        u32 sid_session = SECSID_NULL;
+        struct sec_path *sp = skb->sp;
 
-        sp = skb->sp;
         if (sp) {
                 int i;
 
@@ -248,6 +255,30 @@ out:
 }
 
 /*
+ * LSM hook implementation that checks and/or returns the xfrm sid for the
+ * incoming packet.
+ */
+int selinux_xfrm_decode_session(struct sk_buff *skb, u32 *sid, int ckall)
+{
+        if (skb == NULL) {
+                *sid = SECSID_NULL;
+                return 0;
+        }
+        return selinux_xfrm_skb_sid_ingress(skb, sid, ckall);
+}
+
+int selinux_xfrm_skb_sid(struct sk_buff *skb, u32 *sid)
+{
+        int rc;
+
+        rc = selinux_xfrm_skb_sid_ingress(skb, sid, 0);
+        if (rc == 0 && *sid == SECSID_NULL)
+                *sid = selinux_xfrm_skb_sid_egress(skb);
+
+        return rc;
+}
+
+/*
  * LSM hook implementation that allocs and transfers uctx spec to xfrm_policy.
  */
 int selinux_xfrm_policy_alloc(struct xfrm_sec_ctx **ctxp,
@@ -327,19 +358,22 @@ int selinux_xfrm_state_alloc_acquire(struct xfrm_state *x,
                 return rc;
 
         ctx = kmalloc(sizeof(*ctx) + str_len, GFP_ATOMIC);
-        if (!ctx)
-                return -ENOMEM;
+        if (!ctx) {
+                rc = -ENOMEM;
+                goto out;
+        }
 
         ctx->ctx_doi = XFRM_SC_DOI_LSM;
         ctx->ctx_alg = XFRM_SC_ALG_SELINUX;
         ctx->ctx_sid = secid;
         ctx->ctx_len = str_len;
         memcpy(ctx->ctx_str, ctx_str, str_len);
-        kfree(ctx_str);
 
         x->security = ctx;
         atomic_inc(&selinux_xfrm_refcount);
-        return 0;
+out:
+        kfree(ctx_str);
+        return rc;
 }
 
 /*