5 files changed, 44 insertions, 16 deletions

diff --git a/include/net/inet_frag.h b/include/net/inet_frag.h
index 76c3fe5ecc2e..0a1dcc2fa2f5 100644
--- a/include/net/inet_frag.h
+++ b/include/net/inet_frag.h
@@ -43,6 +43,13 @@ struct inet_frag_queue {
 
 #define INETFRAGS_HASHSZ                64
 
+/* averaged:
+ * max_depth = default ipfrag_high_thresh / INETFRAGS_HASHSZ /
+ *             rounded up (SKB_TRUELEN(0) + sizeof(struct ipq or
+ *             struct frag_queue))
+ */
+#define INETFRAGS_MAXDEPTH              128
+
 struct inet_frags {
         struct hlist_head       hash[INETFRAGS_HASHSZ];
         /* This rwlock is a global lock (seperate per IPv4, IPv6 and
@@ -76,6 +83,8 @@ int inet_frag_evictor(struct netns_frags *nf, struct inet_frags *f, bool force);
 struct inet_frag_queue *inet_frag_find(struct netns_frags *nf,
                 struct inet_frags *f, void *key, unsigned int hash)
         __releases(&f->lock);
+void inet_frag_maybe_warn_overflow(struct inet_frag_queue *q,
+                                   const char *prefix);
 
 static inline void inet_frag_put(struct inet_frag_queue *q, struct inet_frags *f)
 {
diff --git a/net/ipv4/inet_fragment.c b/net/ipv4/inet_fragment.c
index 245ae078a07f..f4fd23de9b13 100644
--- a/net/ipv4/inet_fragment.c
+++ b/net/ipv4/inet_fragment.c
@@ -21,6 +21,7 @@
 #include <linux/rtnetlink.h>
 #include <linux/slab.h>
 
+#include <net/sock.h>
 #include <net/inet_frag.h>
 
 static void inet_frag_secret_rebuild(unsigned long dummy)
@@ -277,6 +278,7 @@ struct inet_frag_queue *inet_frag_find(struct netns_frags *nf,
         __releases(&f->lock)
 {
         struct inet_frag_queue *q;
+        int depth = 0;
 
         hlist_for_each_entry(q, &f->hash[hash], list) {
                 if (q->net == nf && f->match(q, key)) {
@@ -284,9 +286,25 @@ struct inet_frag_queue *inet_frag_find(struct netns_frags *nf,
                         read_unlock(&f->lock);
                         return q;
                 }
+                depth++;
         }
         read_unlock(&f->lock);
 
-        return inet_frag_create(nf, f, key);
+        if (depth <= INETFRAGS_MAXDEPTH)
+                return inet_frag_create(nf, f, key);
+        else
+                return ERR_PTR(-ENOBUFS);
 }
 EXPORT_SYMBOL(inet_frag_find);
+
+void inet_frag_maybe_warn_overflow(struct inet_frag_queue *q,
+                                   const char *prefix)
+{
+        static const char msg[] = "inet_frag_find: Fragment hash bucket"
+                " list length grew over limit " __stringify(INETFRAGS_MAXDEPTH)
+                ". Dropping fragment.\n";
+
+        if (PTR_ERR(q) == -ENOBUFS)
+                LIMIT_NETDEBUG(KERN_WARNING "%s%s", prefix, msg);
+}
+EXPORT_SYMBOL(inet_frag_maybe_warn_overflow);
diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c
index b6d30acb600c..a6445b843ef4 100644
--- a/net/ipv4/ip_fragment.c
+++ b/net/ipv4/ip_fragment.c
@@ -292,14 +292,11 @@ static inline struct ipq *ip_find(struct net *net, struct iphdr *iph, u32 user)
         hash = ipqhashfn(iph->id, iph->saddr, iph->daddr, iph->protocol);
 
         q = inet_frag_find(&net->ipv4.frags, &ip4_frags, &arg, hash);
-        if (q == NULL)
-                goto out_nomem;
-
+        if (IS_ERR_OR_NULL(q)) {
+                inet_frag_maybe_warn_overflow(q, pr_fmt());
+                return NULL;
+        }
         return container_of(q, struct ipq, q);
-
-out_nomem:
-        LIMIT_NETDEBUG(KERN_ERR pr_fmt("ip_frag_create: no memory left !\n"));
-        return NULL;
 }
 
 /* Is the fragment too far ahead to be part of ipq? */
diff --git a/net/ipv6/netfilter/nf_conntrack_reasm.c b/net/ipv6/netfilter/nf_conntrack_reasm.c
index 54087e96d7b8..6700069949dd 100644
--- a/net/ipv6/netfilter/nf_conntrack_reasm.c
+++ b/net/ipv6/netfilter/nf_conntrack_reasm.c
@@ -14,6 +14,8 @@
  * 2 of the License, or (at your option) any later version.
  */
 
+#define pr_fmt(fmt) "IPv6-nf: " fmt
+
 #include <linux/errno.h>
 #include <linux/types.h>
 #include <linux/string.h>
@@ -180,13 +182,11 @@ static inline struct frag_queue *fq_find(struct net *net, __be32 id,
 
         q = inet_frag_find(&net->nf_frag.frags, &nf_frags, &arg, hash);
         local_bh_enable();
-        if (q == NULL)
-                goto oom;
-
+        if (IS_ERR_OR_NULL(q)) {
+                inet_frag_maybe_warn_overflow(q, pr_fmt());
+                return NULL;
+        }
         return container_of(q, struct frag_queue, q);
-
-oom:
-        return NULL;
 }
 
 
diff --git a/net/ipv6/reassembly.c b/net/ipv6/reassembly.c
index 3c6a77290c6e..196ab9347ad1 100644
--- a/net/ipv6/reassembly.c
+++ b/net/ipv6/reassembly.c
@@ -26,6 +26,9 @@
  *      YOSHIFUJI,H. @USAGI     Always remove fragment header to
  *                              calculate ICV correctly.
  */
+
+#define pr_fmt(fmt) "IPv6: " fmt
+
 #include <linux/errno.h>
 #include <linux/types.h>
 #include <linux/string.h>
@@ -185,9 +188,10 @@ fq_find(struct net *net, __be32 id, const struct in6_addr *src, const struct in6
         hash = inet6_hash_frag(id, src, dst, ip6_frags.rnd);
 
         q = inet_frag_find(&net->ipv6.frags, &ip6_frags, &arg, hash);
-        if (q == NULL)
+        if (IS_ERR_OR_NULL(q)) {
+                inet_frag_maybe_warn_overflow(q, pr_fmt());
                 return NULL;
-
+        }
         return container_of(q, struct frag_queue, q);
 }