linux.git/net/ipv6, branch v4.19-rc4

ip: frags: fix crash in ip_do_fragment()

2018-09-09T21:50:56+00:00

A kernel crash occurrs when defragmented packet is fragmented
in ip_do_fragment().
In defragment routine, skb_orphan() is called and
skb->ip_defrag_offset is set. but skb->sk and
skb->ip_defrag_offset are same union member. so that
frag->sk is not NULL.
Hence crash occurrs in skb->sk check routine in ip_do_fragment() when
defragmented packet is fragmented.

test commands:
   %iptables -t nat -I POSTROUTING -j MASQUERADE
   %hping3 192.168.4.2 -s 1000 -p 2000 -d 60000

splat looks like:
[  261.069429] kernel BUG at net/ipv4/ip_output.c:636!
[  261.075753] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN PTI
[  261.083854] CPU: 1 PID: 1349 Comm: hping3 Not tainted 4.19.0-rc2+ #3
[  261.100977] RIP: 0010:ip_do_fragment+0x1613/0x2600
[  261.106945] Code: e8 e2 38 e3 fe 4c 8b 44 24 18 48 8b 74 24 08 e9 92 f6 ff ff 80 3c 02 00 0f 85 da 07 00 00 48 8b b5 d0 00 00 00 e9 25 f6 ff ff <0f> 0b 0f 0b 44 8b 54 24 58 4c 8b 4c 24 18 4c 8b 5c 24 60 4c 8b 6c
[  261.127015] RSP: 0018:ffff8801031cf2c0 EFLAGS: 00010202
[  261.134156] RAX: 1ffff1002297537b RBX: ffffed0020639e6e RCX: 0000000000000004
[  261.142156] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff880114ba9bd8
[  261.150157] RBP: ffff880114ba8a40 R08: ffffed0022975395 R09: ffffed0022975395
[  261.158157] R10: 0000000000000001 R11: ffffed0022975394 R12: ffff880114ba9ca4
[  261.166159] R13: 0000000000000010 R14: ffff880114ba9bc0 R15: dffffc0000000000
[  261.174169] FS:  00007fbae2199700(0000) GS:ffff88011b400000(0000) knlGS:0000000000000000
[  261.183012] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  261.189013] CR2: 00005579244fe000 CR3: 0000000119bf4000 CR4: 00000000001006e0
[  261.198158] Call Trace:
[  261.199018]  ? dst_output+0x180/0x180
[  261.205011]  ? save_trace+0x300/0x300
[  261.209018]  ? ip_copy_metadata+0xb00/0xb00
[  261.213034]  ? sched_clock_local+0xd4/0x140
[  261.218158]  ? kill_l4proto+0x120/0x120 [nf_conntrack]
[  261.223014]  ? rt_cpu_seq_stop+0x10/0x10
[  261.227014]  ? find_held_lock+0x39/0x1c0
[  261.233008]  ip_finish_output+0x51d/0xb50
[  261.237006]  ? ip_fragment.constprop.56+0x220/0x220
[  261.243011]  ? nf_ct_l4proto_register_one+0x5b0/0x5b0 [nf_conntrack]
[  261.250152]  ? rcu_is_watching+0x77/0x120
[  261.255010]  ? nf_nat_ipv4_out+0x1e/0x2b0 [nf_nat_ipv4]
[  261.261033]  ? nf_hook_slow+0xb1/0x160
[  261.265007]  ip_output+0x1c7/0x710
[  261.269005]  ? ip_mc_output+0x13f0/0x13f0
[  261.273002]  ? __local_bh_enable_ip+0xe9/0x1b0
[  261.278152]  ? ip_fragment.constprop.56+0x220/0x220
[  261.282996]  ? nf_hook_slow+0xb1/0x160
[  261.287007]  raw_sendmsg+0x21f9/0x4420
[  261.291008]  ? dst_output+0x180/0x180
[  261.297003]  ? sched_clock_cpu+0x126/0x170
[  261.301003]  ? find_held_lock+0x39/0x1c0
[  261.306155]  ? stop_critical_timings+0x420/0x420
[  261.311004]  ? check_flags.part.36+0x450/0x450
[  261.315005]  ? _raw_spin_unlock_irq+0x29/0x40
[  261.320995]  ? _raw_spin_unlock_irq+0x29/0x40
[  261.326142]  ? cyc2ns_read_end+0x10/0x10
[  261.330139]  ? raw_bind+0x280/0x280
[  261.334138]  ? sched_clock_cpu+0x126/0x170
[  261.338995]  ? check_flags.part.36+0x450/0x450
[  261.342991]  ? __lock_acquire+0x4500/0x4500
[  261.348994]  ? inet_sendmsg+0x11c/0x500
[  261.352989]  ? dst_output+0x180/0x180
[  261.357012]  inet_sendmsg+0x11c/0x500
[ ... ]

v2:
 - clear skb->sk at reassembly routine.(Eric Dumarzet)

Fixes: fa0f527358bd ("ip: use rb trees for IP frag queue.")
Suggested-by: Eric Dumazet 
Signed-off-by: Taehee Yoo 
Reviewed-by: Eric Dumazet 
Signed-off-by: David S. Miller

ip6_tunnel: respect ttl inherit for ip6tnl

2018-09-04T02:04:12+00:00

man ip-tunnel ttl section says:
0 is a special value meaning that packets inherit the TTL value.

IPv4 tunnel respect this in ip_tunnel_xmit(), but IPv6 tunnel has not
implement it yet. To make IPv6 behave consistently with IP tunnel,
add ipv6 tunnel inherit support.

Signed-off-by: Hangbin Liu 
Signed-off-by: David S. Miller

net/ipv6: Only update MTU metric if it set

2018-09-02T21:03:54+00:00

Jan reported a regression after an update to 4.18.5. In this case ipv6
default route is setup by systemd-networkd based on data from an RA. The
RA contains an MTU of 1492 which is used when the route is first inserted
but then systemd-networkd pushes down updates to the default route
without the mtu set.

Prior to the change to fib6_info, metrics such as MTU were held in the
dst_entry and rt6i_pmtu in rt6_info contained an update to the mtu if
any. ip6_mtu would look at rt6i_pmtu first and use it if set. If not,
the value from the metrics is used if it is set and finally falling
back to the idev value.

After the fib6_info change metrics are contained in the fib6_info struct
and there is no equivalent to rt6i_pmtu. To maintain consistency with
the old behavior the new code should only reset the MTU in the metrics
if the route update has it set.

Fixes: d4ead6b34b67 ("net/ipv6: move metrics from dst to rt6_info")
Reported-by: Jan Janssen 
Signed-off-by: David Ahern 
Signed-off-by: David S. Miller

ipv6: don't get lwtstate twice in ip6_rt_copy_init()

2018-09-02T00:42:12+00:00

Commit 80f1a0f4e0cd ("net/ipv6: Put lwtstate when destroying fib6_info")
partially fixed the kmemleak [1], lwtstate can be copied from fib6_info,
with ip6_rt_copy_init(), and it should be done only once there.

rt->dst.lwtstate is set by ip6_rt_init_dst(), at the start of the function
ip6_rt_copy_init(), so there is no need to get it again at the end.

With this patch, lwtstate also isn't copied from RTF_REJECT routes.

[1]:
unreferenced object 0xffff880b6aaa14e0 (size 64):
  comm "ip", pid 10577, jiffies 4295149341 (age 1273.903s)
  hex dump (first 32 bytes):
    01 00 04 00 04 00 00 00 10 00 00 00 00 00 00 00  ................
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<0000000018664623>] lwtunnel_build_state+0x1bc/0x420
    [<00000000b73aa29a>] ip6_route_info_create+0x9f7/0x1fd0
    [<00000000ee2c5d1f>] ip6_route_add+0x14/0x70
    [<000000008537b55c>] inet6_rtm_newroute+0xd9/0xe0
    [<000000002acc50f5>] rtnetlink_rcv_msg+0x66f/0x8e0
    [<000000008d9cd381>] netlink_rcv_skb+0x268/0x3b0
    [<000000004c893c76>] netlink_unicast+0x417/0x5a0
    [<00000000f2ab1afb>] netlink_sendmsg+0x70b/0xc30
    [<00000000890ff0aa>] sock_sendmsg+0xb1/0xf0
    [<00000000a2e7b66f>] ___sys_sendmsg+0x659/0x950
    [<000000001e7426c8>] __sys_sendmsg+0xde/0x170
    [<00000000fe411443>] do_syscall_64+0x9f/0x4a0
    [<000000001be7b28b>] entry_SYSCALL_64_after_hwframe+0x49/0xbe
    [<000000006d21f353>] 0xffffffffffffffff

Fixes: 6edb3c96a5f0 ("net/ipv6: Defer initialization of dst to data path")
Signed-off-by: Alexey Kodanev 
Reviewed-by: David Ahern 
Signed-off-by: David S. Miller

ipv6: fix cleanup ordering for pingv6 registration

2018-08-30T02:28:55+00:00

Commit 6d0bfe226116 ("net: ipv6: Add IPv6 support to the ping socket.")
contains an error in the cleanup path of inet6_init(): when
proto_register(&pingv6_prot, 1) fails, we try to unregister
&pingv6_prot. When rawv6_init() fails, we skip unregistering
&pingv6_prot.

Example of panic (triggered by faking a failure of
 proto_register(&pingv6_prot, 1)):

    general protection fault: 0000 [#1] PREEMPT SMP KASAN PTI
    [...]
    RIP: 0010:__list_del_entry_valid+0x79/0x160
    [...]
    Call Trace:
     proto_unregister+0xbb/0x550
     ? trace_preempt_on+0x6f0/0x6f0
     ? sock_no_shutdown+0x10/0x10
     inet6_init+0x153/0x1b8

Fixes: 6d0bfe226116 ("net: ipv6: Add IPv6 support to the ping socket.")
Signed-off-by: Sabrina Dubroca 
Signed-off-by: David S. Miller

ipv6: fix cleanup ordering for ip6_mr failure

2018-08-30T02:28:55+00:00

Commit 15e668070a64 ("ipv6: reorder icmpv6_init() and ip6_mr_init()")
moved the cleanup label for ipmr_fail, but should have changed the
contents of the cleanup labels as well. Now we can end up cleaning up
icmpv6 even though it hasn't been initialized (jump to icmp_fail or
ipmr_fail).

Simply undo things in the reverse order of their initialization.

Example of panic (triggered by faking a failure of icmpv6_init):

    kasan: GPF could be caused by NULL-ptr deref or user memory access
    general protection fault: 0000 [#1] PREEMPT SMP KASAN PTI
    [...]
    RIP: 0010:__list_del_entry_valid+0x79/0x160
    [...]
    Call Trace:
     ? lock_release+0x8a0/0x8a0
     unregister_pernet_operations+0xd4/0x560
     ? ops_free_list+0x480/0x480
     ? down_write+0x91/0x130
     ? unregister_pernet_subsys+0x15/0x30
     ? down_read+0x1b0/0x1b0
     ? up_read+0x110/0x110
     ? kmem_cache_create_usercopy+0x1b4/0x240
     unregister_pernet_subsys+0x1d/0x30
     icmpv6_cleanup+0x1d/0x30
     inet6_init+0x1b5/0x23f

Fixes: 15e668070a64 ("ipv6: reorder icmpv6_init() and ip6_mr_init()")
Signed-off-by: Sabrina Dubroca 
Signed-off-by: David S. Miller

vti6: remove !skb->ignore_df check from vti6_xmit()

2018-08-30T00:51:44+00:00

Before the commit d6990976af7c ("vti6: fix PMTU caching and reporting
on xmit") '!skb->ignore_df' check was always true because the function
skb_scrub_packet() was called before it, resetting ignore_df to zero.

In the commit, skb_scrub_packet() was moved below, and now this check
can be false for the packet, e.g. when sending it in the two fragments,
this prevents successful PMTU updates in such case. The next attempts
to send the packet lead to the same tx error. Moreover, vti6 initial
MTU value relies on PMTU adjustments.

This issue can be reproduced with the following LTP test script:
    udp_ipsec_vti.sh -6 -p ah -m tunnel -s 2000

Fixes: ccd740cbc6e0 ("vti6: Add pmtu handling to vti6_xmit.")
Signed-off-by: Alexey Kodanev 
Acked-by: Steffen Klassert 
Signed-off-by: David S. Miller

erspan: set erspan_ver to 1 by default when adding an erspan dev

2018-08-27T22:13:17+00:00

After erspan_ver is introudced, if erspan_ver is not set in iproute, its
value will be left 0 by default. Since Commit 02f99df1875c ("erspan: fix
invalid erspan version."), it has broken the traffic due to the version
check in erspan_xmit if users are not aware of 'erspan_ver' param, like
using an old version of iproute.

To fix this compatibility problem, it sets erspan_ver to 1 by default
when adding an erspan dev in erspan_setup. Note that we can't do it in
ipgre_netlink_parms, as this function is also used by ipgre_changelink.

Fixes: 02f99df1875c ("erspan: fix invalid erspan version.")
Reported-by: Jianlin Shi 
Signed-off-by: Xin Long 
Signed-off-by: David S. Miller

net/ipv6: init ip6 anycast rt->dst.input as ip6_input

2018-08-23T04:48:37+00:00

Commit 6edb3c96a5f02 ("net/ipv6: Defer initialization of dst to data path")
forgot to handle anycast route and init anycast rt->dst.input to ip6_forward.
Fix it by setting anycast rt->dst.input back to ip6_input.

Fixes: 6edb3c96a5f02 ("net/ipv6: Defer initialization of dst to data path")
Signed-off-by: Hangbin Liu 
Reviewed-by: David Ahern 
Signed-off-by: David S. Miller

addrconf: reduce unnecessary atomic allocations

2018-08-23T04:42:07+00:00

All the 3 callers of addrconf_add_mroute() assert RTNL
lock, they don't take any additional lock either, so
it is safe to convert it to GFP_KERNEL.

Same for sit_add_v4_addrs().

Cc: David Ahern 
Signed-off-by: Cong Wang 
Reviewed-by: David Ahern 
Signed-off-by: David S. Miller