linux-stable.git/net/ipv6, branch v3.18.67

udp: consistently apply ufo or fragmentation

2017-08-13T02:24:19+00:00

[ Upstream commit 85f1bd9a7b5a79d5baa8bf44af19658f7bf77bfa ]

When iteratively building a UDP datagram with MSG_MORE and that
datagram exceeds MTU, consistently choose UFO or fragmentation.

Once skb_is_gso, always apply ufo. Conversely, once a datagram is
split across multiple skbs, do not consider ufo.

Sendpage already maintains the first invariant, only add the second.
IPv6 does not have a sendpage implementation to modify.

A gso skb must have a partial checksum, do not follow sk_no_check_tx
in udp_send_skb.

Found by syzkaller.

[gregkh - tweaks for 3.18 for ipv6, hopefully they are correct...]

Fixes: e89e9cf539a2 ("[IPv4/IPv6]: UFO Scatter-gather approach")
Reported-by: Andrey Konovalov 
Signed-off-by: Willem de Bruijn 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: avoid skb_warn_bad_offload false positives on UFO

2017-08-13T02:24:19+00:00

[ Upstream commit 8d63bee643f1fb53e472f0e135cae4eb99d62d19 ]

skb_warn_bad_offload triggers a warning when an skb enters the GSO
stack at __skb_gso_segment that does not have CHECKSUM_PARTIAL
checksum offload set.

Commit b2504a5dbef3 ("net: reduce skb_warn_bad_offload() noise")
observed that SKB_GSO_DODGY producers can trigger the check and
that passing those packets through the GSO handlers will fix it
up. But, the software UFO handler will set ip_summed to
CHECKSUM_NONE.

When __skb_gso_segment is called from the receive path, this
triggers the warning again.

Make UFO set CHECKSUM_UNNECESSARY instead of CHECKSUM_NONE. On
Tx these two are equivalent. On Rx, this better matches the
skb state (checksum computed), as CHECKSUM_NONE here means no
checksum computed.

See also this thread for context:
http://patchwork.ozlabs.org/patch/799015/

Fixes: b2504a5dbef3 ("net: reduce skb_warn_bad_offload() noise")
Signed-off-by: Willem de Bruijn 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

ipv6: avoid overflow of offset in ip6_find_1stfragopt

2017-08-11T16:30:14+00:00

[ Upstream commit 6399f1fae4ec29fab5ec76070435555e256ca3a6 ]

In some cases, offset can overflow and can cause an infinite loop in
ip6_find_1stfragopt(). Make it unsigned int to prevent the overflow, and
cap it at IPV6_MAXPLEN, since packets larger than that should be invalid.

This problem has been here since before the beginning of git history.

Signed-off-by: Sabrina Dubroca 
Acked-by: Hannes Frederic Sowa 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

ipv6: Should use consistent conditional judgement for ip6 fragment between __ip6_append_data and ip6_finish_output

2017-08-11T16:30:12+00:00

[ Upstream commit e4c5e13aa45c23692e4acf56f0b3533f328199b2 ]

There is an inconsistent conditional judgement between __ip6_append_data
and ip6_finish_output functions, the variable length in __ip6_append_data
just include the length of application's payload and udp6 header, don't
include the length of ipv6 header, but in ip6_finish_output use
(skb->len > ip6_skb_dst_mtu(skb)) as judgement, and skb->len include the
length of ipv6 header.

That causes some particular application's udp6 payloads whose length are
between (MTU - IPv6 Header) and MTU were fragmented by ip6_fragment even
though the rst->dev support UFO feature.

Add the length of ipv6 header to length in __ip6_append_data to keep
consistent conditional judgement as ip6_finish_output for ip6 fragment.

Signed-off-by: Zheng Li 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

ipv6: fix possible deadlock in ip6_fl_purge / ip6_fl_gc

2017-08-11T16:30:10+00:00

commit 4762fb980465463734f02c67c67f40beb8903f73 upstream.

Use spin_lock_bh in ip6_fl_purge() to prevent following potentially
deadlock scenario between ip6_fl_purge() and ip6_fl_gc() timer.

  =================================
  [ INFO: inconsistent lock state ]
  3.19.0 #1 Not tainted
  ---------------------------------
  inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
  swapper/5/0 [HC0[0]:SC1[1]:HE1:SE0] takes:
   (ip6_fl_lock){+.?...}, at: [] ip6_fl_gc+0x2d/0x180
  {SOFTIRQ-ON-W} state was registered at:
    [] __lock_acquire+0x4a0/0x10b0
    [] lock_acquire+0xc4/0x2b0
    [] _raw_spin_lock+0x3d/0x80
    [] ip6_flowlabel_net_exit+0x28/0x110
    [] ops_exit_list.isra.1+0x39/0x60
    [] cleanup_net+0x100/0x1e0
    [] process_one_work+0x20a/0x830
    [] worker_thread+0x11b/0x460
    [] kthread+0x104/0x120
    [] ret_from_fork+0x7c/0xb0
  irq event stamp: 84640
  hardirqs last  enabled at (84640): [] _raw_spin_unlock_irq+0x30/0x50
  hardirqs last disabled at (84639): [] _raw_spin_lock_irq+0x1f/0x80
  softirqs last  enabled at (84628): [] _local_bh_enable+0x21/0x50
  softirqs last disabled at (84629): [] irq_exit+0x12d/0x150

  other info that might help us debug this:
   Possible unsafe locking scenario:

         CPU0
         ----
    lock(ip6_fl_lock);
    
      lock(ip6_fl_lock);

   *** DEADLOCK ***

Signed-off-by: Jan Stancek 
Signed-off-by: David S. Miller 
Signed-off-by: Amit Pundir 
Signed-off-by: Greg Kroah-Hartman

ipv6: dad: don't remove dynamic addresses if link is down

2017-07-21T06:12:21+00:00

commit ec8add2a4c9df723c94a863b8fcd6d93c472deed upstream.

Currently, when the link for $DEV is down, this command succeeds but the
address is removed immediately by DAD (1):

    ip addr add 1111::12/64 dev $DEV valid_lft 3600 preferred_lft 1800

In the same situation, this will succeed and not remove the address (2):

    ip addr add 1111::12/64 dev $DEV
    ip addr change 1111::12/64 dev $DEV valid_lft 3600 preferred_lft 1800

The comment in addrconf_dad_begin() when !IF_READY makes it look like
this is the intended behavior, but doesn't explain why:

     * If the device is not ready:
     * - keep it tentative if it is a permanent address.
     * - otherwise, kill it.

We clearly cannot prevent userspace from doing (2), but we can make (1)
work consistently with (2).

addrconf_dad_stop() is only called in two cases: if DAD failed, or to
skip DAD when the link is down. In that second case, the fix is to avoid
deleting the address, like we already do for permanent addresses.

Fixes: 3c21edbd1137 ("[IPV6]: Defer IPv6 device initialization until the link becomes ready.")
Signed-off-by: Sabrina Dubroca 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

ipv6: avoid unregistering inet6_dev for loopback

2017-07-21T06:12:21+00:00

commit 60abc0be96e00ca71bac083215ac91ad2e575096 upstream.

The per netns loopback_dev->ip6_ptr is unregistered and set to
NULL when its mtu is set to smaller than IPV6_MIN_MTU, this
leads to that we could set rt->rt6i_idev NULL after a
rt6_uncached_list_flush_dev() and then crash after another
call.

In this case we should just bring its inet6_dev down, rather
than unregistering it, at least prior to commit 176c39af29bc
("netns: fix addrconf_ifdown kernel panic") we always
override the case for loopback.

Thanks a lot to Andrey for finding a reliable reproducer.

Fixes: 176c39af29bc ("netns: fix addrconf_ifdown kernel panic")
Reported-by: Andrey Konovalov 
Cc: Andrey Konovalov 
Cc: Daniel Lezcano 
Cc: David Ahern 
Signed-off-by: Cong Wang 
Acked-by: David Ahern 
Tested-by: Andrey Konovalov 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

ipv6: fix calling in6_ifa_hold incorrectly for dad work

2017-07-05T12:35:13+00:00

[ Upstream commit f8a894b218138888542a5058d0e902378fd0d4ec ]

Now when starting the dad work in addrconf_mod_dad_work, if the dad work
is idle and queued, it needs to hold ifa.

The problem is there's one gap in [1], during which if the pending dad work
is removed elsewhere. It will miss to hold ifa, but the dad word is still
idea and queue.

        if (!delayed_work_pending(&ifp->dad_work))
                in6_ifa_hold(ifp);
                    <--------------[1]
        mod_delayed_work(addrconf_wq, &ifp->dad_work, delay);

An use-after-free issue can be caused by this.

Chen Wei found this issue when WARN_ON(!hlist_unhashed(&ifp->addr_lst)) in
net6_ifa_finish_destroy was hit because of it.

As Hannes' suggestion, this patch is to fix it by holding ifa first in
addrconf_mod_dad_work, then calling mod_delayed_work and putting ifa if
the dad_work is already in queue.

Note that this patch did not choose to fix it with:

  if (!mod_delayed_work(delay))
          in6_ifa_hold(ifp);

As with it, when delay == 0, dad_work would be scheduled immediately, all
addrconf_mod_dad_work(0) callings had to be moved under ifp->lock.

Reported-by: Wei Chen 
Suggested-by: Hannes Frederic Sowa 
Acked-by: Hannes Frederic Sowa 
Signed-off-by: Xin Long 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

ipv6: release dst on error in ip6_dst_lookup_tail

2017-07-05T12:35:12+00:00

commit 00ea1ceebe0d9f2dc1cc2b7bd575a00100c27869 upstream.

If ip6_dst_lookup_tail has acquired a dst and fails the IPv4-mapped
check, release the dst before returning an error.

Fixes: ec5e3b0a1d41 ("ipv6: Inhibit IPv4-mapped src address on the wire.")
Signed-off-by: Willem de Bruijn 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Cc: Ben Hutchings 
Signed-off-by: Greg Kroah-Hartman

ipv6: Inhibit IPv4-mapped src address on the wire.

2017-06-26T05:10:49+00:00

[ Upstream commit ec5e3b0a1d41fbda0cc33a45bc9e54e91d9d12c7 ]

This patch adds a check for the problematic case of an IPv4-mapped IPv6
source address and a destination address that is neither an IPv4-mapped
IPv6 address nor in6addr_any, and returns an appropriate error. The
check in done before returning from looking up the route.

Signed-off-by: Jonathan T. Leighton 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman