From 87c48fa3b4630905f98268dde838ee43626a060c Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 21 Jul 2011 21:25:58 -0700 Subject: ipv6: make fragment identifications less predictable IPv6 fragment identification generation is way beyond what we use for IPv4 : It uses a single generator. Its not scalable and allows DOS attacks. Now inetpeer is IPv6 aware, we can use it to provide a more secure and scalable frag ident generator (per destination, instead of system wide) This patch : 1) defines a new secure_ipv6_id() helper 2) extends inet_getid() to provide 32bit results 3) extends ipv6_select_ident() with a new dest parameter Reported-by: Fernando Gont Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/inetpeer.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'net/ipv4') diff --git a/net/ipv4/inetpeer.c b/net/ipv4/inetpeer.c index 90c5f0d1bcf..e38213817d0 100644 --- a/net/ipv4/inetpeer.c +++ b/net/ipv4/inetpeer.c @@ -391,7 +391,7 @@ static int inet_peer_gc(struct inet_peer_base *base, return cnt; } -struct inet_peer *inet_getpeer(struct inetpeer_addr *daddr, int create) +struct inet_peer *inet_getpeer(const struct inetpeer_addr *daddr, int create) { struct inet_peer __rcu **stack[PEER_MAXDEPTH], ***stackptr; struct inet_peer_base *base = family_to_base(daddr->family); @@ -436,7 +436,10 @@ relookup: p->daddr = *daddr; atomic_set(&p->refcnt, 1); atomic_set(&p->rid, 0); - atomic_set(&p->ip_id_count, secure_ip_id(daddr->addr.a4)); + atomic_set(&p->ip_id_count, + (daddr->family == AF_INET) ? + secure_ip_id(daddr->addr.a4) : + secure_ipv6_id(daddr->addr.a6)); p->tcp_ts_stamp = 0; p->metrics[RTAX_LOCK-1] = INETPEER_METRICS_NEW; p->rate_tokens = 0; -- cgit v1.2.3