linux/net, branch v3.12.1

ipv6: ip6_dst_check needs to check for expired dst_entries

2013-11-20T20:37:36Z

[ Upstream commit e3bc10bd95d7fcc3f2ac690c6ff22833ea6781d6 ] On receiving a packet too big icmp error we check if our current cached dst_entry in the socket is still valid. This validation check did not care about the expiration of the (cached) route. The error path I traced down: The socket receives a packet too big mtu notification. It still has a valid dst_entry and thus issues the ip6_rt_pmtu_update on this dst_entry, setting RTF_EXPIRE and updates the dst.expiration value (which could fail because of not up-to-date expiration values, see previous patch). In some seldom cases we race with a) the ip6_fib gc or b) another routing lookup which would result in a recreation of the cached rt6_info from its parent non-cached rt6_info. While copying the rt6_info we reinitialize the metrics store by copying it over from the parent thus invalidating the just installed pmtu update (both dsts use the same key to the inetpeer storage). The dst_entry with the just invalidated metrics data would just get its RTF_EXPIRES flag cleared and would continue to stay valid for the socket. We should have not issued the pmtu update on the already expired dst_entry in the first placed. By checking the expiration on the dst entry and doing a relookup in case it is out of date we close the race because we would install a new rt6_info into the fib before we issue the pmtu update, thus closing this race. Not reliably updating the dst.expire value was fixed by the patch "ipv6: reset dst.expires value when clearing expire flag". Reported-by: Steinar H. Gunderson Reported-by: Valentijn Sessink Cc: YOSHIFUJI Hideaki Signed-off-by: Hannes Frederic Sowa Reviewed-by: Eric Dumazet Tested-by: Valentijn Sessink Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

tcp: do not rearm RTO when future data are sacked

2013-11-20T20:37:36Z

[ Upstream commit 2f715c1dde6e1760f3101358dc26f8c9489be0bf ] Patch ed08495c3 "tcp: use RTT from SACK for RTO" always re-arms RTO upon obtaining a RTT sample from newly sacked data. But technically RTO should only be re-armed when the data sent before the last (re)transmission of write queue head are (s)acked. Otherwise the RTO may continue to extend during loss recovery on data sent in the future. Note that RTTs from ACK or timestamps do not have this problem, as the RTT source must be from data sent before. The new RTO re-arm policy is 1) Always re-arm RTO if SND.UNA is advanced 2) Re-arm RTO if sack RTT is available, provided the sacked data was sent before the last time write_queue_head was sent. Signed-off-by: Larry Brakmo Signed-off-by: Yuchung Cheng Acked-by: Neal Cardwell Acked-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

tcp: only take RTT from timestamps if new data is acked

2013-11-20T20:37:36Z

[ Upstream commit 2909d874f34eae157aecab0af27c6dc4a1751f8f ] Patch ed08495c3 "tcp: use RTT from SACK for RTO" has a bug that it does not check if the ACK acknowledge new data before taking the RTT sample from TCP timestamps. This patch adds the check back as required by the RFC. Signed-off-by: Yuchung Cheng Acked-by: Neal Cardwell Acked-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

tcp: fix SYNACK RTT estimation in Fast Open

2013-11-20T20:37:36Z

[ Upstream commit bc15afa39ecc16f01c3389d15d8f6015a427fe85 ] tp->lsndtime may not always be the SYNACK timestamp if a passive Fast Open socket sends data before handshake completes. And if the remote acknowledges both the data and the SYNACK, the RTT sample is already taken in tcp_ack(), so no need to call tcp_update_ack_rtt() in tcp_synack_rtt_meas() aagain. Signed-off-by: Yuchung Cheng Acked-by: Neal Cardwell Acked-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

tcp: gso: fix truesize tracking

2013-11-20T20:37:36Z

[ Upstream commit 0d08c42cf9a71530fef5ebcfe368f38f2dd0476f ] commit 6ff50cd55545 ("tcp: gso: do not generate out of order packets") had an heuristic that can trigger a warning in skb_try_coalesce(), because skb->truesize of the gso segments were exactly set to mss. This breaks the requirement that skb->truesize >= skb->len + truesizeof(struct sk_buff); It can trivially be reproduced by : ifconfig lo mtu 1500 ethtool -K lo tso off netperf As the skbs are looped into the TCP networking stack, skb_try_coalesce() warns us of these skb under-estimating their truesize. Signed-off-by: Eric Dumazet Reported-by: Alexei Starovoitov Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: flow_dissector: fail on evil iph->ihl

2013-11-20T20:37:36Z

[ Upstream commit 6f092343855a71e03b8d209815d8c45bf3a27fcd ] We don't validate iph->ihl which may lead a dead loop if we meet a IPIP skb whose iph->ihl is zero. Fix this by failing immediately when iph->ihl is evil (less than 5). This issue were introduced by commit ec5efe7946280d1e84603389a1030ccec0a767ae (rps: support IPIP encapsulation). Signed-off-by: Jason Wang Cc: Eric Dumazet Cc: Petr Matousek Cc: Michael S. Tsirkin Cc: Daniel Borkmann Acked-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: sctp: do not trigger BUG_ON in sctp_cmd_delete_tcb

2013-11-20T20:37:35Z

[ Upstream commit 7926c1d5be0b7cbe5b8d5c788d7d39237e7b212c ] Introduced in f9e42b853523 ("net: sctp: sideeffect: throw BUG if primary_path is NULL"), we intended to find a buggy assoc that's part of the assoc hash table with a primary_path that is NULL. However, we better remove the BUG_ON for now and find a more suitable place to assert for these things as Mark reports that this also triggers the bug when duplication cookie processing happens, and the assoc is not part of the hash table (so all good in this case). Such a situation can for example easily be reproduced by: tc qdisc add dev eth0 root handle 1: prio bands 2 priomap 1 1 1 1 1 1 tc qdisc add dev eth0 parent 1:2 handle 20: netem loss 20% tc filter add dev eth0 protocol ip parent 1: prio 2 u32 match ip \ protocol 132 0xff match u8 0x0b 0xff at 32 flowid 1:2 This drops 20% of COOKIE-ACK packets. After some follow-up discussion with Vlad we came to the conclusion that for now we should still better remove this BUG_ON() assertion, and come up with two follow-ups later on, that is, i) find a more suitable place for this assertion, and possibly ii) have a special allocator/initializer for such kind of temporary assocs. Reported-by: Mark Thomas Signed-off-by: Vlad Yasevich Signed-off-by: Daniel Borkmann Acked-by: Neil Horman Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

Revert "bridge: only expire the mdb entry when query is received"

2013-10-22T18:41:02Z

While this commit was a good attempt to fix issues occuring when no multicast querier is present, this commit still has two more issues: 1) There are cases where mdb entries do not expire even if there is a querier present. The bridge will unnecessarily continue flooding multicast packets on the according ports. 2) Never removing an mdb entry could be exploited for a Denial of Service by an attacker on the local link, slowly, but steadily eating up all memory. Actually, this commit became obsolete with "bridge: disable snooping if there is no querier" (b00589af3b) which included fixes for a few more cases. Therefore reverting the following commits (the commit stated in the commit message plus three of its follow up fixes): ==================== Revert "bridge: update mdb expiration timer upon reports." This reverts commit f144febd93d5ee534fdf23505ab091b2b9088edc. Revert "bridge: do not call setup_timer() multiple times" This reverts commit 1faabf2aab1fdaa1ace4e8c829d1b9cf7bfec2f1. Revert "bridge: fix some kernel warning in multicast timer" This reverts commit c7e8e8a8f7a70b343ca1e0f90a31e35ab2d16de1. Revert "bridge: only expire the mdb entry when query is received" This reverts commit 9f00b2e7cf241fa389733d41b615efdaa2cb0f5b. ==================== CC: Cong Wang Signed-off-by: Linus Lüssing Reviewed-by: Vlad Yasevich Signed-off-by: David S. Miller

tcp: initialize passive-side sk_pacing_rate after 3WHS

2013-10-21T22:56:23Z

For passive TCP connections, upon receiving the ACK that completes the 3WHS, make sure we set our pacing rate after we get our first RTT sample. On passive TCP connections, when we receive the ACK completing the 3WHS we do not take an RTT sample in tcp_ack(), but rather in tcp_synack_rtt_meas(). So upon receiving the ACK that completes the 3WHS, tcp_ack() leaves sk_pacing_rate at its initial value. Originally the initial sk_pacing_rate value was 0, so passive-side connections defaulted to sysctl_tcp_min_tso_segs (2 segs) in skbuffs made in the first RTT. With a default initial cwnd of 10 packets, this happened to be correct for RTTs 5ms or bigger, so it was hard to see problems in WAN or emulated WAN testing. Since 7eec4174ff ("pkt_sched: fq: fix non TCP flows pacing"), the initial sk_pacing_rate is 0xffffffff. So after that change, passive TCP connections were keeping this value (and using large numbers of segments per skbuff) until receiving an ACK for data. Signed-off-by: Neal Cardwell Cc: Eric Dumazet Cc: Yuchung Cheng Acked-by: Eric Dumazet Signed-off-by: David S. Miller

ipv6: probe routes asynchronous in rt6_probe

2013-10-21T22:56:22Z

Routes need to be probed asynchronous otherwise the call stack gets exhausted when the kernel attemps to deliver another skb inline, like e.g. xt_TEE does, and we probe at the same time. We update neigh->updated still at once, otherwise we would send to many probes. Cc: Julian Anastasov Signed-off-by: Hannes Frederic Sowa Signed-off-by: David S. Miller