4 files changed, 16 insertions, 10 deletions

diff --git a/include/linux/netfilter/x_tables.h b/include/linux/netfilter/x_tables.h
index c2ee5d8550cf..c00cc0c4d0b7 100644
--- a/include/linux/netfilter/x_tables.h
+++ b/include/linux/netfilter/x_tables.h
@@ -333,7 +333,7 @@ struct xt_target {
         /* Called when user tries to insert an entry of this type:
            hook_mask is a bitmask of hooks from which it can be
            called. */
-        /* Should return true or false, or an error code (-Exxxx). */
+        /* Should return 0 on success or an error code otherwise (-Exxxx). */
         int (*checkentry)(const struct xt_tgchk_param *);
 
         /* Called when entry of this type deleted. */
diff --git a/include/net/netfilter/nf_conntrack_core.h b/include/net/netfilter/nf_conntrack_core.h
index dffde8e6920e..3d7524fba194 100644
--- a/include/net/netfilter/nf_conntrack_core.h
+++ b/include/net/netfilter/nf_conntrack_core.h
@@ -61,7 +61,7 @@ static inline int nf_conntrack_confirm(struct sk_buff *skb)
         int ret = NF_ACCEPT;
 
         if (ct && ct != &nf_conntrack_untracked) {
-                if (!nf_ct_is_confirmed(ct) && !nf_ct_is_dying(ct))
+                if (!nf_ct_is_confirmed(ct))
                         ret = __nf_conntrack_confirm(skb);
                 if (likely(ret == NF_ACCEPT))
                         nf_ct_deliver_cached_events(ct);
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index b83c530c5e0a..eeeb8bc73982 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -424,6 +424,16 @@ __nf_conntrack_confirm(struct sk_buff *skb)
 
         spin_lock_bh(&nf_conntrack_lock);
 
+        /* We have to check the DYING flag inside the lock to prevent
+           a race against nf_ct_get_next_corpse() possibly called from
+           user context, else we insert an already 'dead' hash, blocking
+           further use of that particular connection -JM */
+
+        if (unlikely(nf_ct_is_dying(ct))) {
+                spin_unlock_bh(&nf_conntrack_lock);
+                return NF_ACCEPT;
+        }
+
         /* See if there's one in the list already, including reverse:
            NAT could have grabbed it without realizing, since we're
            not in the hash.  If there is, we lost race. */
diff --git a/net/netfilter/nf_conntrack_sip.c b/net/netfilter/nf_conntrack_sip.c
index b20f4275893c..53d892210a04 100644
--- a/net/netfilter/nf_conntrack_sip.c
+++ b/net/netfilter/nf_conntrack_sip.c
@@ -1393,10 +1393,8 @@ static int sip_help_tcp(struct sk_buff *skb, unsigned int protoff,
 
         nf_ct_refresh(ct, skb, sip_timeout * HZ);
 
-        if (skb_is_nonlinear(skb)) {
-                pr_debug("Copy of skbuff not supported yet.\n");
-                return NF_ACCEPT;
-        }
+        if (unlikely(skb_linearize(skb)))
+                return NF_DROP;
 
         dptr = skb->data + dataoff;
         datalen = skb->len - dataoff;
@@ -1455,10 +1453,8 @@ static int sip_help_udp(struct sk_buff *skb, unsigned int protoff,
 
         nf_ct_refresh(ct, skb, sip_timeout * HZ);
 
-        if (skb_is_nonlinear(skb)) {
-                pr_debug("Copy of skbuff not supported yet.\n");
-                return NF_ACCEPT;
-        }
+        if (unlikely(skb_linearize(skb)))
+                return NF_DROP;
 
         dptr = skb->data + dataoff;
         datalen = skb->len - dataoff;