security: pass asoc to sctp_assoc_request and sctp_sk_clone

This patch is to move secid and peer_secid from endpoint to association,
and pass asoc to sctp_assoc_request and sctp_sk_clone instead of ep. As
ep is the local endpoint and asoc represents a connection, and in SCTP
one sk/ep could have multiple asoc/connection, saving secid/peer_secid
for new asoc will overwrite the old asoc's.

Note that since asoc can be passed as NULL, security_sctp_assoc_request()
is moved to the place right after the new_asoc is created in
sctp_sf_do_5_1B_init() and sctp_sf_do_unexpected_init().

v1->v2:
  - fix the description of selinux_netlbl_skbuff_setsid(), as Jakub noticed.
  - fix the annotation in selinux_sctp_assoc_request(), as Richard Noticed.

Fixes: 72e89f5 ("security: Add support for SCTP security hooks")
Reported-by: Prashanth Prahlad <[email protected]>
Reviewed-by: Richard Haines <[email protected]>
Tested-by: Richard Haines <[email protected]>
Signed-off-by: Xin Long <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

Documentation/security/SCTP.rst

@@ -26,11 +26,11 @@ described in the `SCTP SELinux Support`_ chapter.
 
 security_sctp_assoc_request()
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-Passes the ``@ep`` and ``@chunk->skb`` of the association INIT packet to the
+Passes the ``@asoc`` and ``@chunk->skb`` of the association INIT packet to the
 security module. Returns 0 on success, error on failure.
 ::
 
-    @ep - pointer to sctp endpoint structure.
+    @asoc - pointer to sctp association structure.
     @skb - pointer to skbuff of association packet.
 
 
@@ -117,9 +117,9 @@ Called whenever a new socket is created by **accept**\(2)
 calls **sctp_peeloff**\(3).
 ::
 
-    @ep - pointer to current sctp endpoint structure.
+    @asoc - pointer to current sctp association structure.
     @sk - pointer to current sock structure.
-    @sk - pointer to new sock structure.
+    @newsk - pointer to new sock structure.
 
 
 security_inet_conn_established()
@@ -200,22 +200,22 @@ hooks with the SELinux specifics expanded below::
 
 security_sctp_assoc_request()
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-Passes the ``@ep`` and ``@chunk->skb`` of the association INIT packet to the
+Passes the ``@asoc`` and ``@chunk->skb`` of the association INIT packet to the
 security module. Returns 0 on success, error on failure.
 ::
 
-    @ep - pointer to sctp endpoint structure.
+    @asoc - pointer to sctp association structure.
     @skb - pointer to skbuff of association packet.
 
 The security module performs the following operations:
-     IF this is the first association on ``@ep->base.sk``, then set the peer
+     IF this is the first association on ``@asoc->base.sk``, then set the peer
      sid to that in ``@skb``. This will ensure there is only one peer sid
-     assigned to ``@ep->base.sk`` that may support multiple associations.
+     assigned to ``@asoc->base.sk`` that may support multiple associations.
 
-     ELSE validate the ``@ep->base.sk peer_sid`` against the ``@skb peer sid``
+     ELSE validate the ``@asoc->base.sk peer_sid`` against the ``@skb peer sid``
      to determine whether the association should be allowed or denied.
 
-     Set the sctp ``@ep sid`` to socket's sid (from ``ep->base.sk``) with
+     Set the sctp ``@asoc sid`` to socket's sid (from ``asoc->base.sk``) with
      MLS portion taken from ``@skb peer sid``. This will be used by SCTP
      TCP style sockets and peeled off connections as they cause a new socket
      to be generated.
@@ -259,13 +259,13 @@ security_sctp_sk_clone()
 Called whenever a new socket is created by **accept**\(2) (i.e. a TCP style
 socket) or when a socket is 'peeled off' e.g userspace calls
 **sctp_peeloff**\(3). ``security_sctp_sk_clone()`` will set the new
-sockets sid and peer sid to that contained in the ``@ep sid`` and
-``@ep peer sid`` respectively.
+sockets sid and peer sid to that contained in the ``@asoc sid`` and
+``@asoc peer sid`` respectively.
 ::
 
-    @ep - pointer to current sctp endpoint structure.
+    @asoc - pointer to current sctp association structure.
     @sk - pointer to current sock structure.
-    @sk - pointer to new sock structure.
+    @newsk - pointer to new sock structure.
 
 
 security_inet_conn_established()

include/linux/lsm_hook_defs.h

@@ -329,11 +329,11 @@ LSM_HOOK(int, 0, tun_dev_create, void)
 LSM_HOOK(int, 0, tun_dev_attach_queue, void *security)
 LSM_HOOK(int, 0, tun_dev_attach, struct sock *sk, void *security)
 LSM_HOOK(int, 0, tun_dev_open, void *security)
-LSM_HOOK(int, 0, sctp_assoc_request, struct sctp_endpoint *ep,
+LSM_HOOK(int, 0, sctp_assoc_request, struct sctp_association *asoc,
 	 struct sk_buff *skb)
 LSM_HOOK(int, 0, sctp_bind_connect, struct sock *sk, int optname,
 	 struct sockaddr *address, int addrlen)
-LSM_HOOK(void, LSM_RET_VOID, sctp_sk_clone, struct sctp_endpoint *ep,
+LSM_HOOK(void, LSM_RET_VOID, sctp_sk_clone, struct sctp_association *asoc,
 	 struct sock *sk, struct sock *newsk)
 #endif /* CONFIG_SECURITY_NETWORK */
 

include/linux/lsm_hooks.h

@@ -1027,9 +1027,9 @@
  * Security hooks for SCTP
  *
  * @sctp_assoc_request:
- *	Passes the @ep and @chunk->skb of the association INIT packet to
+ *	Passes the @asoc and @chunk->skb of the association INIT packet to
  *	the security module.
- *	@ep pointer to sctp endpoint structure.
+ *	@asoc pointer to sctp association structure.
  *	@skb pointer to skbuff of association packet.
  *	Return 0 on success, error on failure.
  * @sctp_bind_connect:
@@ -1047,9 +1047,9 @@
  *	Called whenever a new socket is created by accept(2) (i.e. a TCP
  *	style socket) or when a socket is 'peeled off' e.g userspace
  *	calls sctp_peeloff(3).
- *	@ep pointer to current sctp endpoint structure.
+ *	@asoc pointer to current sctp association structure.
  *	@sk pointer to current sock structure.
- *	@sk pointer to new sock structure.
+ *	@newsk pointer to new sock structure.
  *
  * Security hooks for Infiniband
  *

include/linux/security.h

@@ -179,7 +179,7 @@ struct xfrm_policy;
 struct xfrm_state;
 struct xfrm_user_sec_ctx;
 struct seq_file;
-struct sctp_endpoint;
+struct sctp_association;
 
 #ifdef CONFIG_MMU
 extern unsigned long mmap_min_addr;
@@ -1425,10 +1425,10 @@ int security_tun_dev_create(void);
 int security_tun_dev_attach_queue(void *security);
 int security_tun_dev_attach(struct sock *sk, void *security);
 int security_tun_dev_open(void *security);
-int security_sctp_assoc_request(struct sctp_endpoint *ep, struct sk_buff *skb);
+int security_sctp_assoc_request(struct sctp_association *asoc, struct sk_buff *skb);
 int security_sctp_bind_connect(struct sock *sk, int optname,
 			       struct sockaddr *address, int addrlen);
-void security_sctp_sk_clone(struct sctp_endpoint *ep, struct sock *sk,
+void security_sctp_sk_clone(struct sctp_association *asoc, struct sock *sk,
 			    struct sock *newsk);
 
 #else	/* CONFIG_SECURITY_NETWORK */
@@ -1631,7 +1631,7 @@ static inline int security_tun_dev_open(void *security)
 	return 0;
 }
 
-static inline int security_sctp_assoc_request(struct sctp_endpoint *ep,
+static inline int security_sctp_assoc_request(struct sctp_association *asoc,
 					      struct sk_buff *skb)
 {
 	return 0;
@@ -1644,7 +1644,7 @@ static inline int security_sctp_bind_connect(struct sock *sk, int optname,
 	return 0;
 }
 
-static inline void security_sctp_sk_clone(struct sctp_endpoint *ep,
+static inline void security_sctp_sk_clone(struct sctp_association *asoc,
 					  struct sock *sk,
 					  struct sock *newsk)
 {

include/net/sctp/structs.h

@@ -1355,16 +1355,6 @@ struct sctp_endpoint {
 	      reconf_enable:1;
 
 	__u8  strreset_enable;
-
-	/* Security identifiers from incoming (INIT). These are set by
-	 * security_sctp_assoc_request(). These will only be used by
-	 * SCTP TCP type sockets and peeled off connections as they
-	 * cause a new socket to be generated. security_sctp_sk_clone()
-	 * will then plug these into the new socket.
-	 */
-
-	u32 secid;
-	u32 peer_secid;
 };
 
 /* Recover the outter endpoint structure. */
@@ -2104,6 +2094,16 @@ struct sctp_association {
 	__u64 abandoned_unsent[SCTP_PR_INDEX(MAX) + 1];
 	__u64 abandoned_sent[SCTP_PR_INDEX(MAX) + 1];
 
+	/* Security identifiers from incoming (INIT). These are set by
+	 * security_sctp_assoc_request(). These will only be used by
+	 * SCTP TCP type sockets and peeled off connections as they
+	 * cause a new socket to be generated. security_sctp_sk_clone()
+	 * will then plug these into the new socket.
+	 */
+
+	u32 secid;
+	u32 peer_secid;
+
 	struct rcu_head rcu;
 };
 

net/sctp/sm_statefuns.c

@@ -326,11 +326,6 @@ enum sctp_disposition sctp_sf_do_5_1B_init(struct net *net,
 	struct sctp_packet *packet;
 	int len;
 
-	/* Update socket peer label if first association. */
-	if (security_sctp_assoc_request((struct sctp_endpoint *)ep,
-					chunk->skb))
-		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
-
 	/* 6.10 Bundling
 	 * An endpoint MUST NOT bundle INIT, INIT ACK or
 	 * SHUTDOWN COMPLETE with any other chunks.
@@ -415,6 +410,12 @@ enum sctp_disposition sctp_sf_do_5_1B_init(struct net *net,
 	if (!new_asoc)
 		goto nomem;
 
+	/* Update socket peer label if first association. */
+	if (security_sctp_assoc_request(new_asoc, chunk->skb)) {
+		sctp_association_free(new_asoc);
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+	}
+
 	if (sctp_assoc_set_bind_addr_from_ep(new_asoc,
 					     sctp_scope(sctp_source(chunk)),
 					     GFP_ATOMIC) < 0)
@@ -780,7 +781,6 @@ enum sctp_disposition sctp_sf_do_5_1D_ce(struct net *net,
 		}
 	}
 
-
 	/* Delay state machine commands until later.
 	 *
 	 * Re-build the bind address for the association is done in
@@ -1517,11 +1517,6 @@ static enum sctp_disposition sctp_sf_do_unexpected_init(
 	struct sctp_packet *packet;
 	int len;
 
-	/* Update socket peer label if first association. */
-	if (security_sctp_assoc_request((struct sctp_endpoint *)ep,
-					chunk->skb))
-		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
-
 	/* 6.10 Bundling
 	 * An endpoint MUST NOT bundle INIT, INIT ACK or
 	 * SHUTDOWN COMPLETE with any other chunks.
@@ -1594,6 +1589,12 @@ static enum sctp_disposition sctp_sf_do_unexpected_init(
 	if (!new_asoc)
 		goto nomem;
 
+	/* Update socket peer label if first association. */
+	if (security_sctp_assoc_request(new_asoc, chunk->skb)) {
+		sctp_association_free(new_asoc);
+		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+	}
+
 	if (sctp_assoc_set_bind_addr_from_ep(new_asoc,
 				sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0)
 		goto nomem;
@@ -2255,8 +2256,7 @@ enum sctp_disposition sctp_sf_do_5_2_4_dupcook(
 	}
 
 	/* Update socket peer label if first association. */
-	if (security_sctp_assoc_request((struct sctp_endpoint *)ep,
-					chunk->skb)) {
+	if (security_sctp_assoc_request(new_asoc, chunk->skb)) {
 		sctp_association_free(new_asoc);
 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
 	}

net/sctp/socket.c

@@ -9412,7 +9412,6 @@ void sctp_copy_sock(struct sock *newsk, struct sock *sk,
 	struct inet_sock *inet = inet_sk(sk);
 	struct inet_sock *newinet;
 	struct sctp_sock *sp = sctp_sk(sk);
-	struct sctp_endpoint *ep = sp->ep;
 
 	newsk->sk_type = sk->sk_type;
 	newsk->sk_bound_dev_if = sk->sk_bound_dev_if;
@@ -9457,9 +9456,9 @@ void sctp_copy_sock(struct sock *newsk, struct sock *sk,
 		net_enable_timestamp();
 
 	/* Set newsk security attributes from original sk and connection
-	 * security attribute from ep.
+	 * security attribute from asoc.
 	 */
-	security_sctp_sk_clone(ep, sk, newsk);
+	security_sctp_sk_clone(asoc, sk, newsk);
 }
 
 static inline void sctp_copy_descendant(struct sock *sk_to,

security/security.c

@@ -2367,9 +2367,9 @@ int security_tun_dev_open(void *security)
 }
 EXPORT_SYMBOL(security_tun_dev_open);
 
-int security_sctp_assoc_request(struct sctp_endpoint *ep, struct sk_buff *skb)
+int security_sctp_assoc_request(struct sctp_association *asoc, struct sk_buff *skb)
 {
-	return call_int_hook(sctp_assoc_request, 0, ep, skb);
+	return call_int_hook(sctp_assoc_request, 0, asoc, skb);
 }
 EXPORT_SYMBOL(security_sctp_assoc_request);
 
@@ -2381,10 +2381,10 @@ int security_sctp_bind_connect(struct sock *sk, int optname,
 }
 EXPORT_SYMBOL(security_sctp_bind_connect);
 
-void security_sctp_sk_clone(struct sctp_endpoint *ep, struct sock *sk,
+void security_sctp_sk_clone(struct sctp_association *asoc, struct sock *sk,
 			    struct sock *newsk)
 {
-	call_void_hook(sctp_sk_clone, ep, sk, newsk);
+	call_void_hook(sctp_sk_clone, asoc, sk, newsk);
 }
 EXPORT_SYMBOL(security_sctp_sk_clone);
 

security/selinux/hooks.c

@@ -5339,10 +5339,10 @@ static void selinux_sock_graft(struct sock *sk, struct socket *parent)
  * connect(2), sctp_connectx(3) or sctp_sendmsg(3) (with no association
  * already present).
  */
-static int selinux_sctp_assoc_request(struct sctp_endpoint *ep,
+static int selinux_sctp_assoc_request(struct sctp_association *asoc,
 				      struct sk_buff *skb)
 {
-	struct sk_security_struct *sksec = ep->base.sk->sk_security;
+	struct sk_security_struct *sksec = asoc->base.sk->sk_security;
 	struct common_audit_data ad;
 	struct lsm_network_audit net = {0,};
 	u8 peerlbl_active;
@@ -5359,7 +5359,7 @@ static int selinux_sctp_assoc_request(struct sctp_endpoint *ep,
 		/* This will return peer_sid = SECSID_NULL if there are
 		 * no peer labels, see security_net_peersid_resolve().
 		 */
-		err = selinux_skb_peerlbl_sid(skb, ep->base.sk->sk_family,
+		err = selinux_skb_peerlbl_sid(skb, asoc->base.sk->sk_family,
 					      &peer_sid);
 		if (err)
 			return err;
@@ -5383,7 +5383,7 @@ static int selinux_sctp_assoc_request(struct sctp_endpoint *ep,
 		 */
 		ad.type = LSM_AUDIT_DATA_NET;
 		ad.u.net = &net;
-		ad.u.net->sk = ep->base.sk;
+		ad.u.net->sk = asoc->base.sk;
 		err = avc_has_perm(&selinux_state,
 				   sksec->peer_sid, peer_sid, sksec->sclass,
 				   SCTP_SOCKET__ASSOCIATION, &ad);
@@ -5392,7 +5392,7 @@ static int selinux_sctp_assoc_request(struct sctp_endpoint *ep,
 	}
 
 	/* Compute the MLS component for the connection and store
-	 * the information in ep. This will be used by SCTP TCP type
+	 * the information in asoc. This will be used by SCTP TCP type
 	 * sockets and peeled off connections as they cause a new
 	 * socket to be generated. selinux_sctp_sk_clone() will then
 	 * plug this into the new socket.
@@ -5401,11 +5401,11 @@ static int selinux_sctp_assoc_request(struct sctp_endpoint *ep,
 	if (err)
 		return err;
 
-	ep->secid = conn_sid;
-	ep->peer_secid = peer_sid;
+	asoc->secid = conn_sid;
+	asoc->peer_secid = peer_sid;
 
 	/* Set any NetLabel labels including CIPSO/CALIPSO options. */
-	return selinux_netlbl_sctp_assoc_request(ep, skb);
+	return selinux_netlbl_sctp_assoc_request(asoc, skb);
 }
 
 /* Check if sctp IPv4/IPv6 addresses are valid for binding or connecting
@@ -5490,7 +5490,7 @@ static int selinux_sctp_bind_connect(struct sock *sk, int optname,
 }
 
 /* Called whenever a new socket is created by accept(2) or sctp_peeloff(3). */
-static void selinux_sctp_sk_clone(struct sctp_endpoint *ep, struct sock *sk,
+static void selinux_sctp_sk_clone(struct sctp_association *asoc, struct sock *sk,
 				  struct sock *newsk)
 {
 	struct sk_security_struct *sksec = sk->sk_security;
@@ -5502,8 +5502,8 @@ static void selinux_sctp_sk_clone(struct sctp_endpoint *ep, struct sock *sk,
 	if (!selinux_policycap_extsockclass())
 		return selinux_sk_clone_security(sk, newsk);
 
-	newsksec->sid = ep->secid;
-	newsksec->peer_sid = ep->peer_secid;
+	newsksec->sid = asoc->secid;
+	newsksec->peer_sid = asoc->peer_secid;
 	newsksec->sclass = sksec->sclass;
 	selinux_netlbl_sctp_sk_clone(sk, newsk);
 }

security/selinux/include/netlabel.h

@@ -39,7 +39,7 @@ int selinux_netlbl_skbuff_getsid(struct sk_buff *skb,
 int selinux_netlbl_skbuff_setsid(struct sk_buff *skb,
 				 u16 family,
 				 u32 sid);
-int selinux_netlbl_sctp_assoc_request(struct sctp_endpoint *ep,
+int selinux_netlbl_sctp_assoc_request(struct sctp_association *asoc,
 				     struct sk_buff *skb);
 int selinux_netlbl_inet_conn_request(struct request_sock *req, u16 family);
 void selinux_netlbl_inet_csk_clone(struct sock *sk, u16 family);
@@ -98,7 +98,7 @@ static inline int selinux_netlbl_skbuff_setsid(struct sk_buff *skb,
 	return 0;
 }
 
-static inline int selinux_netlbl_sctp_assoc_request(struct sctp_endpoint *ep,
+static inline int selinux_netlbl_sctp_assoc_request(struct sctp_association *asoc,
 						    struct sk_buff *skb)
 {
 	return 0;