1 files changed, 25 insertions, 2 deletions

diff --git a/net/sctp/ulpqueue.c b/net/sctp/ulpqueue.c
index 2080b2d28c98..575e556aeb3e 100644
--- a/net/sctp/ulpqueue.c
+++ b/net/sctp/ulpqueue.c
@@ -279,6 +279,7 @@ static inline void sctp_ulpq_store_reasm(struct sctp_ulpq *ulpq,
 static struct sctp_ulpevent *sctp_make_reassembled_event(struct sk_buff_head *queue, struct sk_buff *f_frag, struct sk_buff *l_frag)
 {
         struct sk_buff *pos;
+        struct sk_buff *new = NULL;
         struct sctp_ulpevent *event;
         struct sk_buff *pnext, *last;
         struct sk_buff *list = skb_shinfo(f_frag)->frag_list;
@@ -297,11 +298,33 @@ static struct sctp_ulpevent *sctp_make_reassembled_event(struct sk_buff_head *qu
          */
         if (last)
                 last->next = pos;
-        else
-                skb_shinfo(f_frag)->frag_list = pos;
+        else {
+                if (skb_cloned(f_frag)) {
+                        /* This is a cloned skb, we can't just modify
+                         * the frag_list.  We need a new skb to do that.
+                         * Instead of calling skb_unshare(), we'll do it
+                         * ourselves since we need to delay the free.
+                         */
+                        new = skb_copy(f_frag, GFP_ATOMIC);
+                        if (!new)
+                                return NULL;    /* try again later */
+
+                        new->sk = f_frag->sk;
+
+                        skb_shinfo(new)->frag_list = pos;
+                } else
+                        skb_shinfo(f_frag)->frag_list = pos;
+        }
 
         /* Remove the first fragment from the reassembly queue.  */
         __skb_unlink(f_frag, queue);
+
+        /* if we did unshare, then free the old skb and re-assign */
+        if (new) {
+                kfree_skb(f_frag);
+                f_frag = new;
+        }
+
         while (pos) {
 
                 pnext = pos->next;