[SCTP]: Fix potential null pointer dereference while handling an icmp error

Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/sctp/sctp.h

@@ -167,15 +167,12 @@ void sctp_unhash_established(struct sctp_association *);
 void sctp_hash_endpoint(struct sctp_endpoint *);
 void sctp_unhash_endpoint(struct sctp_endpoint *);
 struct sock *sctp_err_lookup(int family, struct sk_buff *,
-			     struct sctphdr *, struct sctp_endpoint **,
-			     struct sctp_association **,
+			     struct sctphdr *, struct sctp_association **,
 			     struct sctp_transport **);
-void sctp_err_finish(struct sock *, struct sctp_endpoint *,
-			    struct sctp_association *);
+void sctp_err_finish(struct sock *, struct sctp_association *);
 void sctp_icmp_frag_needed(struct sock *, struct sctp_association *,
 			   struct sctp_transport *t, __u32 pmtu);
 void sctp_icmp_proto_unreachable(struct sock *sk,
-				 struct sctp_endpoint *ep,
 				 struct sctp_association *asoc,
 				 struct sctp_transport *t);
 

net/sctp/input.c

@@ -351,7 +351,6 @@ void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc,
  *
  */
 void sctp_icmp_proto_unreachable(struct sock *sk,
-                           struct sctp_endpoint *ep,
                            struct sctp_association *asoc,
                            struct sctp_transport *t)
 {
@@ -367,7 +366,6 @@ void sctp_icmp_proto_unreachable(struct sock *sk,
 /* Common lookup code for icmp/icmpv6 error handler. */
 struct sock *sctp_err_lookup(int family, struct sk_buff *skb,
 			     struct sctphdr *sctphdr,
-			     struct sctp_endpoint **epp,
 			     struct sctp_association **app,
 			     struct sctp_transport **tpp)
 {
@@ -375,11 +373,10 @@ struct sock *sctp_err_lookup(int family, struct sk_buff *skb,
 	union sctp_addr daddr;
 	struct sctp_af *af;
 	struct sock *sk = NULL;
-	struct sctp_endpoint *ep = NULL;
 	struct sctp_association *asoc = NULL;
 	struct sctp_transport *transport = NULL;
 
-	*app = NULL; *epp = NULL; *tpp = NULL;
+	*app = NULL; *tpp = NULL;
 
 	af = sctp_get_af_specific(family);
 	if (unlikely(!af)) {
@@ -394,26 +391,15 @@ struct sock *sctp_err_lookup(int family, struct sk_buff *skb,
 	 * packet.
 	 */
 	asoc = __sctp_lookup_association(&saddr, &daddr, &transport);
-	if (!asoc) {
-		/* If there is no matching association, see if it matches any
-		 * endpoint. This may happen for an ICMP error generated in
-		 * response to an INIT_ACK.
-		 */
-		ep = __sctp_rcv_lookup_endpoint(&daddr);
-		if (!ep) {
+	if (!asoc)
 		return NULL;
-		}
-	}
 
-	if (asoc) {
 	sk = asoc->base.sk;
 
 	if (ntohl(sctphdr->vtag) != asoc->c.peer_vtag) {
 		ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
 		goto out;
 	}
-	} else
-		sk = ep->base.sk;
 
 	sctp_bh_lock_sock(sk);
 
@@ -423,7 +409,6 @@ struct sock *sctp_err_lookup(int family, struct sk_buff *skb,
 	if (sock_owned_by_user(sk))
 		NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS);
 
-	*epp = ep;
 	*app = asoc;
 	*tpp = transport;
 	return sk;
@@ -432,21 +417,16 @@ struct sock *sctp_err_lookup(int family, struct sk_buff *skb,
 	sock_put(sk);
 	if (asoc)
 		sctp_association_put(asoc);
-	if (ep)
-		sctp_endpoint_put(ep);
 	return NULL;
 }
 
 /* Common cleanup code for icmp/icmpv6 error handler. */
-void sctp_err_finish(struct sock *sk, struct sctp_endpoint *ep,
-		     struct sctp_association *asoc)
+void sctp_err_finish(struct sock *sk, struct sctp_association *asoc)
 {
 	sctp_bh_unlock_sock(sk);
 	sock_put(sk);
 	if (asoc)
 		sctp_association_put(asoc);
-	if (ep)
-		sctp_endpoint_put(ep);
 }
 
 /*
@@ -471,7 +451,6 @@ void sctp_v4_err(struct sk_buff *skb, __u32 info)
 	int type = skb->h.icmph->type;
 	int code = skb->h.icmph->code;
 	struct sock *sk;
-	struct sctp_endpoint *ep;
 	struct sctp_association *asoc;
 	struct sctp_transport *transport;
 	struct inet_sock *inet;
@@ -488,7 +467,7 @@ void sctp_v4_err(struct sk_buff *skb, __u32 info)
 	savesctp  = skb->h.raw;
 	skb->nh.iph = iph;
 	skb->h.raw = (char *)sh;
-	sk = sctp_err_lookup(AF_INET, skb, sh, &ep, &asoc, &transport);
+	sk = sctp_err_lookup(AF_INET, skb, sh, &asoc, &transport);
 	/* Put back, the original pointers. */
 	skb->nh.raw = saveip;
 	skb->h.raw = savesctp;
@@ -515,7 +494,7 @@ void sctp_v4_err(struct sk_buff *skb, __u32 info)
 		}
 		else {
 			if (ICMP_PROT_UNREACH == code) {
-				sctp_icmp_proto_unreachable(sk, ep, asoc,
+				sctp_icmp_proto_unreachable(sk, asoc,
 							    transport);
 				goto out_unlock;
 			}
@@ -544,7 +523,7 @@ void sctp_v4_err(struct sk_buff *skb, __u32 info)
 	}
 
 out_unlock:
-	sctp_err_finish(sk, ep, asoc);
+	sctp_err_finish(sk, asoc);
 }
 
 /*

net/sctp/ipv6.c

@@ -91,7 +91,6 @@ SCTP_STATIC void sctp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 	struct ipv6hdr *iph = (struct ipv6hdr *)skb->data;
 	struct sctphdr *sh = (struct sctphdr *)(skb->data + offset);
 	struct sock *sk;
-	struct sctp_endpoint *ep;
 	struct sctp_association *asoc;
 	struct sctp_transport *transport;
 	struct ipv6_pinfo *np;
@@ -105,7 +104,7 @@ SCTP_STATIC void sctp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 	savesctp  = skb->h.raw;
 	skb->nh.ipv6h = iph;
 	skb->h.raw = (char *)sh;
-	sk = sctp_err_lookup(AF_INET6, skb, sh, &ep, &asoc, &transport);
+	sk = sctp_err_lookup(AF_INET6, skb, sh, &asoc, &transport);
 	/* Put back, the original pointers. */
 	skb->nh.raw = saveip;
 	skb->h.raw = savesctp;
@@ -124,7 +123,7 @@ SCTP_STATIC void sctp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 		goto out_unlock;
 	case ICMPV6_PARAMPROB:
 		if (ICMPV6_UNK_NEXTHDR == code) {
-			sctp_icmp_proto_unreachable(sk, ep, asoc, transport);
+			sctp_icmp_proto_unreachable(sk, asoc, transport);
 			goto out_unlock;
 		}
 		break;
@@ -142,7 +141,7 @@ SCTP_STATIC void sctp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 	}
 
 out_unlock:
-	sctp_err_finish(sk, ep, asoc);
+	sctp_err_finish(sk, asoc);
 out:
 	if (likely(idev != NULL))
 		in6_dev_put(idev);