kernel.git/net/ipv6/ip6_output.c, branch linux-2.6.32.y

udp: only allow UFO for packets from SOCK_DGRAM sockets

2015-05-24T08:10:47Z

[ Upstream commit acf8dd0a9d0b9e4cdb597c2f74802f79c699e802 ] If an over-MTU UDP datagram is sent through a SOCK_RAW socket to a UFO-capable device, ip_ufo_append_data() sets skb->ip_summed to CHECKSUM_PARTIAL unconditionally as all GSO code assumes transport layer checksum is to be computed on segmentation. However, in this case, skb->csum_start and skb->csum_offset are never set as raw socket transmit path bypasses udp_send_skb() where they are usually set. As a result, driver may access invalid memory when trying to calculate the checksum and store the result (as observed in virtio_net driver). Moreover, the very idea of modifying the userspace provided UDP header is IMHO against raw socket semantics (I wasn't able to find a document clearly stating this or the opposite, though). And while allowing CHECKSUM_NONE in the UFO case would be more efficient, it would be a bit too intrusive change just to handle a corner case like this. Therefore disallowing UFO for packets from SOCK_DGRAM seems to be the best option. Signed-off-by: Michal Kubecek Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings (cherry picked from commit 332640b2821f75381b1049a904d93d4fb846334f) Signed-off-by: Willy Tarreau

inet: fix possible memory corruption with UDP_CORK and UFO

2014-05-19T05:54:21Z

[ This is a simplified -stable version of a set of upstream commits. ] This is a replacement patch only for stable which does fix the problems handled by the following two commits in -net: "ip_output: do skb ufo init for peeked non ufo skb as well" (e93b7d748be887cd7639b113ba7d7ef792a7efb9) "ip6_output: do skb ufo init for peeked non ufo skb as well" (c547dbf55d5f8cf615ccc0e7265e98db27d3fb8b) Three frames are written on a corked udp socket for which the output netdevice has UFO enabled. If the first and third frame are smaller than the mtu and the second one is bigger, we enqueue the second frame with skb_append_datato_frags without initializing the gso fields. This leads to the third frame appended regulary and thus constructing an invalid skb. This fixes the problem by always using skb_append_datato_frags as soon as the first frag got enqueued to the skb without marking the packet as SKB_GSO_UDP. The problem with only two frames for ipv6 was fixed by "ipv6: udp packets following an UFO enqueued packet need also be handled by UFO" (2811ebac2521ceac84f2bdae402455baa6a7fb47). Cc: Jiri Pirko Cc: Eric Dumazet Cc: David Miller Signed-off-by: Hannes Frederic Sowa Signed-off-by: Greg Kroah-Hartman Signed-off-by: Ben Hutchings (cherry picked from commit 5124ae99ac8a8f63d0fca9b75adaef40b20678ff) Signed-off-by: Willy Tarreau

ipv6: udp packets following an UFO enqueued packet need also be handled by UFO

2014-05-19T05:54:20Z

In the following scenario the socket is corked: If the first UDP packet is larger then the mtu we try to append it to the write queue via ip6_ufo_append_data. A following packet, which is smaller than the mtu would be appended to the already queued up gso-skb via plain ip6_append_data. This causes random memory corruptions. In ip6_ufo_append_data we also have to be careful to not queue up the same skb multiple times. So setup the gso frame only when no first skb is available. This also fixes a shortcoming where we add the current packet's length to cork->length but return early because of a packet > mtu with dontfrag set (instead of sutracting it again). Found with trinity. Cc: YOSHIFUJI Hideaki Signed-off-by: Hannes Frederic Sowa Reported-by: Dmitry Vyukov Signed-off-by: David S. Miller (cherry picked from commit 2811ebac2521ceac84f2bdae402455baa6a7fb47) [wt: 2.6.32 doesn't have dontfrag so remove the optimization] Signed-off-by: Willy Tarreau

ipv6: fix possible seqlock deadlock in ip6_finish_output2

2014-05-19T05:54:05Z

[ Upstream commit 7f88c6b23afbd31545c676dea77ba9593a1a14bf ] IPv6 stats are 64 bits and thus are protected with a seqlock. By not disabling bottom-half we could deadlock here if we don't disable bh and a softirq reentrantly updates the same mib. Cc: Eric Dumazet Signed-off-by: Hannes Frederic Sowa Acked-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Willy Tarreau

ipv6: fix possible crashes in ip6_cork_release()

2014-05-19T05:53:42Z

[ Upstream commit 284041ef21fdf2e0d216ab6b787bc9072b4eb58a ] commit 0178b695fd6b4 ("ipv6: Copy cork options in ip6_append_data") added some code duplication and bad error recovery, leading to potential crash in ip6_cork_release() as kfree() could be called with garbage. use kzalloc() to make sure this wont happen. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Cc: Herbert Xu Cc: Hideaki YOSHIFUJI Cc: Neal Cardwell Signed-off-by: Willy Tarreau

ipv6: ip6_sk_dst_check() must not assume ipv6 dst

2014-05-19T05:53:17Z

commit a963a37d384d71ad43b3e9e79d68d42fbe0901f3 upstream It's possible to use AF_INET6 sockets and to connect to an IPv4 destination. After this, socket dst cache is a pointer to a rtable, not rt6_info. ip6_sk_dst_check() should check the socket dst cache is IPv6, or else various corruptions/crashes can happen. Dave Jones can reproduce immediate crash with trinity -q -l off -n -c sendmsg -c connect With help from Hannes Frederic Sowa Reported-by: Dave Jones Reported-by: Hannes Frederic Sowa Signed-off-by: Eric Dumazet Acked-by: Hannes Frederic Sowa Signed-off-by: David S. Miller Signed-off-by: Willy Tarreau

ipv6: make fragment identifications less predictable

2013-06-10T09:43:37Z

[ Backport of upstream commit 87c48fa3b4630905f98268dde838ee43626a060c ] Fernando Gont reported current IPv6 fragment identification generation was not secure, because using a very predictable system-wide generator, allowing various attacks. IPv4 uses inetpeer cache to address this problem and to get good performance. We'll use this mechanism when IPv6 inetpeer is stable enough in linux-3.1 For the time being, we use jhash on destination address to provide less predictable identifications. Also remove a spinlock and use cmpxchg() to get better SMP performance. Reported-by: Fernando Gont Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman [bwh: Backport further to 2.6.32] Signed-off-by: Ben Hutchings Signed-off-by: Willy Tarreau

ipv6: Add GSO support on forwarding path

2011-11-07T20:31:51Z

commit 0aa68271510ae2b221d4b60892103837be63afe4 upstream. Currently we disallow GSO packets on the IPv6 forward path. This patch fixes this. Note that I discovered that our existing GSO MTU checks (e.g., IPv4 forwarding) are buggy in that they skip the check altogether, when they really should be checking gso_size + header instead. I have also been lazy here in that I haven't bothered to segment the GSO packet by hand before generating an ICMP message. Someone should add that to be 100% correct. Reported-by: Ralf Baechle Signed-off-by: Herbert Xu Signed-off-by: David S. Miller Signed-off-by: Apollon Oikonomopoulos Signed-off-by: Faidon Liambotis Signed-off-by: Greg Kroah-Hartman

ip: fix truesize mismatch in ip fragmentation

2010-10-29T04:44:08Z

[ Upstream commit 3d13008e7345fa7a79d8f6438150dc15d6ba6e9d ] Special care should be taken when slow path is hit in ip_fragment() : When walking through frags, we transfert truesize ownership from skb to frags. Then if we hit a slow_path condition, we must undo this or risk uncharging frags->truesize twice, and in the end, having negative socket sk_wmem_alloc counter, or even freeing socket sooner than expected. Many thanks to Nick Bowler, who provided a very clean bug report and test program. Thanks to Jarek for reviewing my first patch and providing a V2 While Nick bisection pointed to commit 2b85a34e911 (net: No more expensive sock_hold()/sock_put() on each tx), underlying bug is older (2.6.12-rc5) A side effect is to extend work done in commit b2722b1c3a893e (ip_fragment: also adjust skb->truesize for packets not owned by a socket) to ipv6 as well. Reported-and-bisected-by: Nick Bowler Tested-by: Nick Bowler Signed-off-by: Eric Dumazet CC: Jarek Poplawski CC: Patrick McHardy Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

ip: Report qdisc packet drops

2009-09-03T01:05:33Z

Christoph Lameter pointed out that packet drops at qdisc level where not accounted in SNMP counters. Only if application sets IP_RECVERR, drops are reported to user (-ENOBUFS errors) and SNMP counters updated. IP_RECVERR is used to enable extended reliable error message passing, but these are not needed to update system wide SNMP stats. This patch changes things a bit to allow SNMP counters to be updated, regardless of IP_RECVERR being set or not on the socket. Example after an UDP tx flood # netstat -s ... IP: 1487048 outgoing packets dropped ... Udp: ... SndbufErrors: 1487048 send() syscalls, do however still return an OK status, to not break applications. Note : send() manual page explicitly says for -ENOBUFS error : "The output queue for a network interface was full. This generally indicates that the interface has stopped sending, but may be caused by transient congestion. (Normally, this does not occur in Linux. Packets are just silently dropped when a device queue overflows.) " This is not true for IP_RECVERR enabled sockets : a send() syscall that hit a qdisc drop returns an ENOBUFS error. Many thanks to Christoph, David, and last but not least, Alexey ! Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller