[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>

3 files changed, 17 insertions, 42 deletions

diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h
index 4a26adfaed71..e1d5ec1c23c0 100644
--- a/include/net/sctp/sctp.h
+++ b/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);
 
diff --git a/net/sctp/input.c b/net/sctp/input.c
index 5e085e041a6e..742be9171b7d 100644
--- a/net/sctp/input.c
+++ b/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) {
-                        return NULL;
-                }
-        }
+        if (!asoc)
+                return NULL;
 
-        if (asoc) {
-                sk = asoc->base.sk;
+        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;
+        if (ntohl(sctphdr->vtag) != asoc->c.peer_vtag) {
+                ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
+                goto out;
+        }
 
         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 @@ out:
         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);
 }
 
 /*
diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
index c7e42d125b9c..e9b2fd480d61 100644
--- a/net/sctp/ipv6.c
+++ b/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);