Merge branch 'frag_hash_secret'

Hannes Frederic Sowa says:

====================
initialize fragment hash secrets with net_get_random_once

This series switches the inet_frag.rnd hash initialization to
net_get_random_once.

Included patches:
 ipv4: initialize ip4_frags hash secret as late
 ipv6: split inet6_hash_frag for netfilter and
 inet: remove old fragmentation hash initializing
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/inet_frag.h

@@ -64,6 +64,10 @@ struct inet_frags {
 	rwlock_t		lock ____cacheline_aligned_in_smp;
 	int			secret_interval;
 	struct timer_list	secret_timer;
+
+	/* The first call to hashfn is responsible to initialize
+	 * rnd. This is best done with net_get_random_once.
+	 */
 	u32			rnd;
 	int			qsize;
 

include/net/ipv6.h

@@ -805,8 +805,6 @@ int ip6_mc_source(int add, int omode, struct sock *sk,
 int ip6_mc_msfilter(struct sock *sk, struct group_filter *gsf);
 int ip6_mc_msfget(struct sock *sk, struct group_filter *gsf,
 		  struct group_filter __user *optval, int __user *optlen);
-unsigned int inet6_hash_frag(__be32 id, const struct in6_addr *saddr,
-			     const struct in6_addr *daddr, u32 rnd);
 
 #ifdef CONFIG_PROC_FS
 int ac6_proc_init(struct net *net);

net/ipv4/inet_fragment.c

@@ -93,9 +93,6 @@ void inet_frags_init(struct inet_frags *f)
 	}
 	rwlock_init(&f->lock);
 
-	f->rnd = (u32) ((totalram_pages ^ (totalram_pages >> 7)) ^
-				   (jiffies ^ (jiffies >> 6)));
-
 	setup_timer(&f->secret_timer, inet_frag_secret_rebuild,
 			(unsigned long)f);
 	f->secret_timer.expires = jiffies + f->secret_interval;

net/ipv4/ip_fragment.c

@@ -106,6 +106,7 @@ struct ip4_create_arg {
 
 static unsigned int ipqhashfn(__be16 id, __be32 saddr, __be32 daddr, u8 prot)
 {
+	net_get_random_once(&ip4_frags.rnd, sizeof(ip4_frags.rnd));
 	return jhash_3words((__force u32)id << 16 | prot,
 			    (__force u32)saddr, (__force u32)daddr,
 			    ip4_frags.rnd) & (INETFRAGS_HASHSZ - 1);

net/ipv6/netfilter/nf_conntrack_reasm.c

@@ -144,12 +144,24 @@ static inline u8 ip6_frag_ecn(const struct ipv6hdr *ipv6h)
 	return 1 << (ipv6_get_dsfield(ipv6h) & INET_ECN_MASK);
 }
 
+static unsigned int nf_hash_frag(__be32 id, const struct in6_addr *saddr,
+				 const struct in6_addr *daddr)
+{
+	u32 c;
+
+	net_get_random_once(&nf_frags.rnd, sizeof(nf_frags.rnd));
+	c = jhash_3words(ipv6_addr_hash(saddr), ipv6_addr_hash(daddr),
+			 (__force u32)id, nf_frags.rnd);
+	return c & (INETFRAGS_HASHSZ - 1);
+}
+
+
 static unsigned int nf_hashfn(struct inet_frag_queue *q)
 {
 	const struct frag_queue *nq;
 
 	nq = container_of(q, struct frag_queue, q);
-	return inet6_hash_frag(nq->id, &nq->saddr, &nq->daddr, nf_frags.rnd);
+	return nf_hash_frag(nq->id, &nq->saddr, &nq->daddr);
 }
 
 static void nf_skb_free(struct sk_buff *skb)
@@ -185,7 +197,7 @@ static inline struct frag_queue *fq_find(struct net *net, __be32 id,
 	arg.ecn = ecn;
 
 	read_lock_bh(&nf_frags.lock);
-	hash = inet6_hash_frag(id, src, dst, nf_frags.rnd);
+	hash = nf_hash_frag(id, src, dst);
 
 	q = inet_frag_find(&net->nf_frag.frags, &nf_frags, &arg, hash);
 	local_bh_enable();

net/ipv6/reassembly.c

@@ -82,24 +82,24 @@ static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
  * callers should be careful not to use the hash value outside the ipfrag_lock
  * as doing so could race with ipfrag_hash_rnd being recalculated.
  */
-unsigned int inet6_hash_frag(__be32 id, const struct in6_addr *saddr,
-			     const struct in6_addr *daddr, u32 rnd)
+static unsigned int inet6_hash_frag(__be32 id, const struct in6_addr *saddr,
+				    const struct in6_addr *daddr)
 {
 	u32 c;
 
+	net_get_random_once(&ip6_frags.rnd, sizeof(ip6_frags.rnd));
 	c = jhash_3words(ipv6_addr_hash(saddr), ipv6_addr_hash(daddr),
-			 (__force u32)id, rnd);
+			 (__force u32)id, ip6_frags.rnd);
 
 	return c & (INETFRAGS_HASHSZ - 1);
 }
-EXPORT_SYMBOL_GPL(inet6_hash_frag);
 
 static unsigned int ip6_hashfn(struct inet_frag_queue *q)
 {
 	struct frag_queue *fq;
 
 	fq = container_of(q, struct frag_queue, q);
-	return inet6_hash_frag(fq->id, &fq->saddr, &fq->daddr, ip6_frags.rnd);
+	return inet6_hash_frag(fq->id, &fq->saddr, &fq->daddr);
 }
 
 bool ip6_frag_match(struct inet_frag_queue *q, void *a)
@@ -193,7 +193,7 @@ fq_find(struct net *net, __be32 id, const struct in6_addr *src,
 	arg.ecn = ecn;
 
 	read_lock(&ip6_frags.lock);
-	hash = inet6_hash_frag(id, src, dst, ip6_frags.rnd);
+	hash = inet6_hash_frag(id, src, dst);
 
 	q = inet_frag_find(&net->ipv6.frags, &ip6_frags, &arg, hash);
 	if (IS_ERR_OR_NULL(q)) {