From 996b44fcef8f216ea0b6b6e74468c5a77b5e341f Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Mon, 9 Oct 2017 14:52:10 +0200 Subject: udp: fix bcast packet reception The commit bc044e8db796 ("udp: perform source validation for mcast early demux") does not take into account that broadcast packets lands in the same code path and they need different checks for the source address - notably, zero source address are valid for bcast and invalid for mcast. As a result, 2nd and later broadcast packets with 0 source address landing to the same socket are dropped. This breaks dhcp servers. Since we don't have stringent performance requirements for ingress broadcast traffic, fix it by disabling UDP early demux such traffic. Reported-by: Hannes Frederic Sowa Fixes: bc044e8db796 ("udp: perform source validation for mcast early demux") Signed-off-by: Paolo Abeni Signed-off-by: David S. Miller --- net/ipv4/udp.c | 14 +++++--------- 1 file changed, 5 insertions(+), 9 deletions(-) (limited to 'net/ipv4/udp.c') diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 5676237d2b0f..e45177ceb0ee 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -2240,20 +2240,16 @@ int udp_v4_early_demux(struct sk_buff *skb) iph = ip_hdr(skb); uh = udp_hdr(skb); - if (skb->pkt_type == PACKET_BROADCAST || - skb->pkt_type == PACKET_MULTICAST) { + if (skb->pkt_type == PACKET_MULTICAST) { in_dev = __in_dev_get_rcu(skb->dev); if (!in_dev) return 0; - /* we are supposed to accept bcast packets */ - if (skb->pkt_type == PACKET_MULTICAST) { - ours = ip_check_mc_rcu(in_dev, iph->daddr, iph->saddr, - iph->protocol); - if (!ours) - return 0; - } + ours = ip_check_mc_rcu(in_dev, iph->daddr, iph->saddr, + iph->protocol); + if (!ours) + return 0; sk = __udp4_lib_mcast_demux_lookup(net, uh->dest, iph->daddr, uh->source, iph->saddr, -- cgit v1.2.3 From 197df02cb3d3e969fb1d6fc11f5a634b7bfc2124 Mon Sep 17 00:00:00 2001 From: Matteo Croce Date: Thu, 19 Oct 2017 14:22:17 +0200 Subject: udp: make some messages more descriptive In the UDP code there are two leftover error messages with very few meaning. Replace them with a more descriptive error message as some users reported them as "strange network error". Signed-off-by: Matteo Croce Signed-off-by: David S. Miller --- net/ipv4/udp.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'net/ipv4/udp.c') diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index e45177ceb0ee..806b298a3bdd 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -1061,7 +1061,7 @@ back_from_confirm: /* ... which is an evident application bug. --ANK */ release_sock(sk); - net_dbg_ratelimited("cork app bug 2\n"); + net_dbg_ratelimited("socket already corked\n"); err = -EINVAL; goto out; } @@ -1144,7 +1144,7 @@ int udp_sendpage(struct sock *sk, struct page *page, int offset, if (unlikely(!up->pending)) { release_sock(sk); - net_dbg_ratelimited("udp cork app bug 3\n"); + net_dbg_ratelimited("cork failed\n"); return -EINVAL; } -- cgit v1.2.3 From 1b5f962e71bfad6284574655c406597535c3ea7a Mon Sep 17 00:00:00 2001 From: Craig Gallek Date: Thu, 19 Oct 2017 15:00:29 -0400 Subject: soreuseport: fix initialization race Syzkaller stumbled upon a way to trigger WARNING: CPU: 1 PID: 13881 at net/core/sock_reuseport.c:41 reuseport_alloc+0x306/0x3b0 net/core/sock_reuseport.c:39 There are two initialization paths for the sock_reuseport structure in a socket: Through the udp/tcp bind paths of SO_REUSEPORT sockets or through SO_ATTACH_REUSEPORT_[CE]BPF before bind. The existing implementation assumedthat the socket lock protected both of these paths when it actually only protects the SO_ATTACH_REUSEPORT path. Syzkaller triggered this double allocation by running these paths concurrently. This patch moves the check for double allocation into the reuseport_alloc function which is protected by a global spin lock. Fixes: e32ea7e74727 ("soreuseport: fast reuseport UDP socket selection") Fixes: c125e80b8868 ("soreuseport: fast reuseport TCP socket selection") Signed-off-by: Craig Gallek Signed-off-by: David S. Miller --- net/ipv4/udp.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) (limited to 'net/ipv4/udp.c') diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 806b298a3bdd..ebfbccae62fd 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -231,10 +231,7 @@ static int udp_reuseport_add_sock(struct sock *sk, struct udp_hslot *hslot) } } - /* Initial allocation may have already happened via setsockopt */ - if (!rcu_access_pointer(sk->sk_reuseport_cb)) - return reuseport_alloc(sk); - return 0; + return reuseport_alloc(sk); } /** -- cgit v1.2.3