[SCTP]: Add bind hash locking to the migrate code

SCTP accept code tries to add a newliy created socket
to a bind bucket without holding a lock.   On a really
busy system, that can causes slab corruptions.
Add a lock around this code.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 0 deletions

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index ff8bc95670ed..9f5d7930f54d 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -6325,6 +6325,7 @@ static void sctp_sock_migrate(struct sock *oldsk, struct sock *newsk,
         struct sctp_endpoint *newep = newsp->ep;
         struct sk_buff *skb, *tmp;
         struct sctp_ulpevent *event;
+        struct sctp_bind_hashbucket *head;
         int flags = 0;
 
         /* Migrate socket buffer sizes and all the socket level options to the
@@ -6342,10 +6343,15 @@ static void sctp_sock_migrate(struct sock *oldsk, struct sock *newsk,
         newsp->hmac = NULL;
 
         /* Hook this new socket in to the bind_hash list. */
+        head = &sctp_port_hashtable[sctp_phashfn(inet_sk(oldsk)->num)];
+        sctp_local_bh_disable();
+        sctp_spin_lock(&head->lock);
         pp = sctp_sk(oldsk)->bind_hash;
         sk_add_bind_node(newsk, &pp->owner);
         sctp_sk(newsk)->bind_hash = pp;
         inet_sk(newsk)->num = inet_sk(oldsk)->num;
+        sctp_spin_unlock(&head->lock);
+        sctp_local_bh_enable();
 
         /* Copy the bind_addr list from the original endpoint to the new
          * endpoint so that we can handle restarts properly