sctp: fix association hangs due to errors when reneging events from the ordering queue

In sctp_ulpq_renege_list(), events being reneged from the
ordering queue may correspond to multiple TSNs.  Identify
all affected packets; sum freed space and renege from the
tsnmap.

Signed-off-by: Lee A. Roberts <lee.roberts@hp.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>

1 files changed, 22 insertions, 4 deletions

diff --git a/net/sctp/ulpqueue.c b/net/sctp/ulpqueue.c
index 63afddcbcd2c..f221fbbc80ac 100644
--- a/net/sctp/ulpqueue.c
+++ b/net/sctp/ulpqueue.c
@@ -962,8 +962,8 @@ static __u16 sctp_ulpq_renege_list(struct sctp_ulpq *ulpq,
                 struct sk_buff_head *list, __u16 needed)
 {
         __u16 freed = 0;
-        __u32 tsn;
-        struct sk_buff *skb;
+        __u32 tsn, last_tsn;
+        struct sk_buff *skb, *flist, *last;
         struct sctp_ulpevent *event;
         struct sctp_tsnmap *tsnmap;
 
@@ -977,10 +977,28 @@ static __u16 sctp_ulpq_renege_list(struct sctp_ulpq *ulpq,
                 if (TSN_lte(tsn, sctp_tsnmap_get_ctsn(tsnmap)))
                         break;
 
-                __skb_unlink(skb, list);
+                /* Events in ordering queue may have multiple fragments
+                 * corresponding to additional TSNs.  Sum the total
+                 * freed space; find the last TSN.
+                 */
                 freed += skb_headlen(skb);
+                flist = skb_shinfo(skb)->frag_list;
+                for (last = flist; flist; flist = flist->next) {
+                        last = flist;
+                        freed += skb_headlen(last);
+                }
+                if (last)
+                        last_tsn = sctp_skb2event(last)->tsn;
+                else
+                        last_tsn = tsn;
+
+                /* Unlink the event, then renege all applicable TSNs. */
+                __skb_unlink(skb, list);
                 sctp_ulpevent_free(event);
-                sctp_tsnmap_renege(tsnmap, tsn);
+                while (TSN_lte(tsn, last_tsn)) {
+                        sctp_tsnmap_renege(tsnmap, tsn);
+                        tsn++;
+                }
                 if (freed >= needed)
                         return freed;
         }