4 files changed, 75 insertions, 22 deletions

diff --git a/net/sctp/inqueue.c b/net/sctp/inqueue.c
index 297b8951463e..cf0c767d43ae 100644
--- a/net/sctp/inqueue.c
+++ b/net/sctp/inqueue.c
@@ -149,6 +149,7 @@ struct sctp_chunk *sctp_inq_pop(struct sctp_inq *queue)
                 /* This is the first chunk in the packet.  */
                 chunk->singleton = 1;
                 ch = (sctp_chunkhdr_t *) chunk->skb->data;
+                chunk->data_accepted = 0;
         }
 
         chunk->chunk_hdr = ch;
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index 2b9a832b29a7..8cdba51ec076 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -636,8 +636,9 @@ sctp_disposition_t sctp_sf_do_5_1D_ce(const struct sctp_endpoint *ep,
          */
         chunk->subh.cookie_hdr =
                 (struct sctp_signed_cookie *)chunk->skb->data;
-        skb_pull(chunk->skb,
-                 ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t));
+        if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
+                                         sizeof(sctp_chunkhdr_t)))
+                goto nomem;
 
         /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint
          * "Z" will reply with a COOKIE ACK chunk after building a TCB
@@ -965,7 +966,8 @@ sctp_disposition_t sctp_sf_beat_8_3(const struct sctp_endpoint *ep,
          */
         chunk->subh.hb_hdr = (sctp_heartbeathdr_t *) chunk->skb->data;
         paylen = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t);
-        skb_pull(chunk->skb, paylen);
+        if (!pskb_pull(chunk->skb, paylen))
+                goto nomem;
 
         reply = sctp_make_heartbeat_ack(asoc, chunk,
                                         chunk->subh.hb_hdr, paylen);
@@ -1860,8 +1862,9 @@ sctp_disposition_t sctp_sf_do_5_2_4_dupcook(const struct sctp_endpoint *ep,
          * are in good shape.
          */
         chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data;
-        skb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
-                 sizeof(sctp_chunkhdr_t));
+        if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
+                                        sizeof(sctp_chunkhdr_t)))
+                goto nomem;
 
         /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie
          * of a duplicate COOKIE ECHO match the Verification Tags of the
@@ -5151,7 +5154,9 @@ static int sctp_eat_data(const struct sctp_association *asoc,
         int tmp;
         __u32 tsn;
         int account_value;
+        struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map;
         struct sock *sk = asoc->base.sk;
+        int rcvbuf_over = 0;
 
         data_hdr = chunk->subh.data_hdr = (sctp_datahdr_t *)chunk->skb->data;
         skb_pull(chunk->skb, sizeof(sctp_datahdr_t));
@@ -5162,10 +5167,16 @@ static int sctp_eat_data(const struct sctp_association *asoc,
         /* ASSERT:  Now skb->data is really the user data.  */
 
         /*
-         * if we are established, and we have used up our receive
-         * buffer memory, drop the frame
-         */
-        if (asoc->state == SCTP_STATE_ESTABLISHED) {
+         * If we are established, and we have used up our receive buffer
+         * memory, think about droping the frame.
+         * Note that we have an opportunity to improve performance here.
+         * If we accept one chunk from an skbuff, we have to keep all the
+         * memory of that skbuff around until the chunk is read into user
+         * space. Therefore, once we accept 1 chunk we may as well accept all
+         * remaining chunks in the skbuff. The data_accepted flag helps us do
+         * that.
+         */
+        if ((asoc->state == SCTP_STATE_ESTABLISHED) && (!chunk->data_accepted)) {
                 /*
                  * If the receive buffer policy is 1, then each
                  * association can allocate up to sk_rcvbuf bytes
@@ -5176,9 +5187,25 @@ static int sctp_eat_data(const struct sctp_association *asoc,
                         account_value = atomic_read(&asoc->rmem_alloc);
                 else
                         account_value = atomic_read(&sk->sk_rmem_alloc);
-
-                if (account_value > sk->sk_rcvbuf)
-                        return SCTP_IERROR_IGNORE_TSN;
+                if (account_value > sk->sk_rcvbuf) {
+                        /*
+                         * We need to make forward progress, even when we are
+                         * under memory pressure, so we always allow the
+                         * next tsn after the ctsn ack point to be accepted.
+                         * This lets us avoid deadlocks in which we have to
+                         * drop frames that would otherwise let us drain the
+                         * receive queue.
+                         */
+                        if ((sctp_tsnmap_get_ctsn(map) + 1) != tsn)
+                                return SCTP_IERROR_IGNORE_TSN;
+
+                        /*
+                         * We're going to accept the frame but we should renege
+                         * to make space for it. This will send us down that
+                         * path later in this function.
+                         */
+                        rcvbuf_over = 1;
+                }
         }
 
         /* Process ECN based congestion.
@@ -5226,6 +5253,7 @@ static int sctp_eat_data(const struct sctp_association *asoc,
         datalen -= sizeof(sctp_data_chunk_t);
 
         deliver = SCTP_CMD_CHUNK_ULP;
+        chunk->data_accepted = 1;
 
         /* Think about partial delivery. */
         if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) {
@@ -5242,7 +5270,8 @@ static int sctp_eat_data(const struct sctp_association *asoc,
          * large spill over.
          */
         if (!asoc->rwnd || asoc->rwnd_over ||
-            (datalen > asoc->rwnd + asoc->frag_point)) {
+            (datalen > asoc->rwnd + asoc->frag_point) ||
+            rcvbuf_over) {
 
                 /* If this is the next TSN, consider reneging to make
                  * room.   Note: Playing nice with a confused sender.  A
@@ -5250,8 +5279,8 @@ static int sctp_eat_data(const struct sctp_association *asoc,
                  * space and in the future we may want to detect and
                  * do more drastic reneging.
                  */
-                if (sctp_tsnmap_has_gap(&asoc->peer.tsn_map) &&
-                    (sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map) + 1) == tsn) {
+                if (sctp_tsnmap_has_gap(map) &&
+                    (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
                         SCTP_DEBUG_PRINTK("Reneging for tsn:%u\n", tsn);
                         deliver = SCTP_CMD_RENEGE;
                 } else {
diff --git a/net/sctp/sm_statetable.c b/net/sctp/sm_statetable.c
index 75ef10408764..8bcca5676151 100644
--- a/net/sctp/sm_statetable.c
+++ b/net/sctp/sm_statetable.c
@@ -366,9 +366,9 @@ const sctp_sm_table_entry_t *sctp_sm_lookup_event(sctp_event_t event_type,
         /* SCTP_STATE_EMPTY */ \
         {.fn = sctp_sf_ootb, .name = "sctp_sf_ootb"}, \
         /* SCTP_STATE_CLOSED */ \
-        {.fn = sctp_sf_bug, .name = "sctp_sf_bug"}, \
+        {.fn = sctp_sf_discard_chunk, .name = "sctp_sf_discard_chunk"}, \
         /* SCTP_STATE_COOKIE_WAIT */ \
-        {.fn = sctp_sf_bug, .name = "sctp_sf_bug"}, \
+        {.fn = sctp_sf_discard_chunk, .name = "sctp_sf_discard_chunk"}, \
         /* SCTP_STATE_COOKIE_ECHOED */ \
         {.fn = sctp_sf_do_ecne, .name = "sctp_sf_do_ecne"}, \
         /* SCTP_STATE_ESTABLISHED */ \
@@ -380,7 +380,7 @@ const sctp_sm_table_entry_t *sctp_sm_lookup_event(sctp_event_t event_type,
         /* SCTP_STATE_SHUTDOWN_RECEIVED */ \
         {.fn = sctp_sf_do_ecne, .name = "sctp_sf_do_ecne"}, \
         /* SCTP_STATE_SHUTDOWN_ACK_SENT */ \
-        {.fn = sctp_sf_bug, .name = "sctp_sf_bug"}, \
+        {.fn = sctp_sf_discard_chunk, .name = "sctp_sf_discard_chunk"}, \
 } /* TYPE_SCTP_ECN_ECNE */
 
 #define TYPE_SCTP_ECN_CWR { \
@@ -401,7 +401,7 @@ const sctp_sm_table_entry_t *sctp_sm_lookup_event(sctp_event_t event_type,
         /* SCTP_STATE_SHUTDOWN_RECEIVED */ \
         {.fn = sctp_sf_discard_chunk, .name = "sctp_sf_discard_chunk"}, \
         /* SCTP_STATE_SHUTDOWN_ACK_SENT */ \
-        {.fn = sctp_sf_bug, .name = "sctp_sf_bug"}, \
+        {.fn = sctp_sf_discard_chunk, .name = "sctp_sf_discard_chunk"}, \
 } /* TYPE_SCTP_ECN_CWR */
 
 #define TYPE_SCTP_SHUTDOWN_COMPLETE { \
@@ -647,7 +647,7 @@ chunk_event_table_unknown[SCTP_STATE_NUM_STATES] = {
         /* SCTP_STATE_EMPTY */ \
         {.fn = sctp_sf_bug, .name = "sctp_sf_bug"}, \
         /* SCTP_STATE_CLOSED */ \
-        {.fn = sctp_sf_bug, .name = "sctp_sf_bug"}, \
+        {.fn = sctp_sf_error_closed, .name = "sctp_sf_error_closed"}, \
         /* SCTP_STATE_COOKIE_WAIT */ \
         {.fn = sctp_sf_do_prm_requestheartbeat,               \
          .name = "sctp_sf_do_prm_requestheartbeat"},          \
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;