linux-stable.git/net, branch v3.18.91

net: ipv4: fix for a race condition in raw_sendmsg

2018-01-02T19:04:59+00:00

[ Upstream commit 8f659a03a0ba9289b9aeb9b4470e6fb263d6f483 ]

inet->hdrincl is racy, and could lead to uninitialized stack pointer
usage, so its value should be read only once.

Fixes: c008ba5bdc9f ("ipv4: Avoid reading user iov twice after raw_probe_proto_opt")
Signed-off-by: Mohamed Ghannam 
Reviewed-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

sctp: Replace use of sockets_allocated with specified macro.

2018-01-02T19:04:59+00:00

[ Upstream commit 8cb38a602478e9f806571f6920b0a3298aabf042 ]

The patch(180d8cd942ce) replaces all uses of struct sock fields'
memory_pressure, memory_allocated, sockets_allocated, and sysctl_mem
to accessor macros. But the sockets_allocated field of sctp sock is
not replaced at all. Then replace it now for unifying the code.

Fixes: 180d8cd942ce ("foundations of per-cgroup memory pressure controlling.")
Cc: Glauber Costa 
Signed-off-by: Tonghao Zhang 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

tcp md5sig: Use skb's saddr when replying to an incoming segment

2018-01-02T19:04:58+00:00

[ Upstream commit 30791ac41927ebd3e75486f9504b6d2280463bf0 ]

The MD5-key that belongs to a connection is identified by the peer's
IP-address. When we are in tcp_v4(6)_reqsk_send_ack(), we are replying
to an incoming segment from tcp_check_req() that failed the seq-number
checks.

Thus, to find the correct key, we need to use the skb's saddr and not
the daddr.

This bug seems to have been there since quite a while, but probably got
unnoticed because the consequences are not catastrophic. We will call
tcp_v4_reqsk_send_ack only to send a challenge-ACK back to the peer,
thus the connection doesn't really fail.

Fixes: 9501f9722922 ("tcp md5sig: Let the caller pass appropriate key for tcp_v{4,6}_do_calc_md5_hash().")
Signed-off-by: Christoph Paasch 
Reviewed-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

netlink: Add netns check on taps

2018-01-02T19:04:58+00:00

[ Upstream commit 93c647643b48f0131f02e45da3bd367d80443291 ]

Currently, a nlmon link inside a child namespace can observe systemwide
netlink activity.  Filter the traffic so that nlmon can only sniff
netlink messages from its own netns.

Test case:

    vpnns -- bash -c "ip link add nlmon0 type nlmon; \
                      ip link set nlmon0 up; \
                      tcpdump -i nlmon0 -q -w /tmp/nlmon.pcap -U" &
    sudo ip xfrm state add src 10.1.1.1 dst 10.1.1.2 proto esp \
        spi 0x1 mode transport \
        auth sha1 0x6162633132330000000000000000000000000000 \
        enc aes 0x00000000000000000000000000000000
    grep --binary abc123 /tmp/nlmon.pcap

Signed-off-by: Kevin Cernekee 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: igmp: Use correct source address on IGMPv3 reports

2018-01-02T19:04:58+00:00

[ Upstream commit a46182b00290839fa3fa159d54fd3237bd8669f0 ]

Closing a multicast socket after the final IPv4 address is deleted
from an interface can generate a membership report that uses the
source IP from a different interface.  The following test script, run
from an isolated netns, reproduces the issue:

    #!/bin/bash

    ip link add dummy0 type dummy
    ip link add dummy1 type dummy
    ip link set dummy0 up
    ip link set dummy1 up
    ip addr add 10.1.1.1/24 dev dummy0
    ip addr add 192.168.99.99/24 dev dummy1

    tcpdump -U -i dummy0 &
    socat EXEC:"sleep 2" \
        UDP4-DATAGRAM:239.101.1.68:8889,ip-add-membership=239.0.1.68:10.1.1.1 &

    sleep 1
    ip addr del 10.1.1.1/24 dev dummy0
    sleep 5
    kill %tcpdump

RFC 3376 specifies that the report must be sent with a valid IP source
address from the destination subnet, or from address 0.0.0.0.  Add an
extra check to make sure this is the case.

Signed-off-by: Kevin Cernekee 
Reviewed-by: Andrew Lunn 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

ipv6: mcast: better catch silly mtu values

2018-01-02T19:04:58+00:00

[ Upstream commit b9b312a7a451e9c098921856e7cfbc201120e1a7 ]

syzkaller reported crashes in IPv6 stack [1]

Xin Long found that lo MTU was set to silly values.

IPv6 stack reacts to changes to small MTU, by disabling itself under
RTNL.

But there is a window where threads not using RTNL can see a wrong
device mtu. This can lead to surprises, in mld code where it is assumed
the mtu is suitable.

Fix this by reading device mtu once and checking IPv6 minimal MTU.

[1]
 skbuff: skb_over_panic: text:0000000010b86b8d len:196 put:20
 head:000000003b477e60 data:000000000e85441e tail:0xd4 end:0xc0 dev:lo
 ------------[ cut here ]------------
 kernel BUG at net/core/skbuff.c:104!
 invalid opcode: 0000 [#1] SMP KASAN
 Dumping ftrace buffer:
    (ftrace buffer empty)
 Modules linked in:
 CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.15.0-rc2-mm1+ #39
 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
 Google 01/01/2011
 RIP: 0010:skb_panic+0x15c/0x1f0 net/core/skbuff.c:100
 RSP: 0018:ffff8801db307508 EFLAGS: 00010286
 RAX: 0000000000000082 RBX: ffff8801c517e840 RCX: 0000000000000000
 RDX: 0000000000000082 RSI: 1ffff1003b660e61 RDI: ffffed003b660e95
 RBP: ffff8801db307570 R08: 1ffff1003b660e23 R09: 0000000000000000
 R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff85bd4020
 R13: ffffffff84754ed2 R14: 0000000000000014 R15: ffff8801c4e26540
 FS:  0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 0000000000463610 CR3: 00000001c6698000 CR4: 00000000001406e0
 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
 Call Trace:
  
  skb_over_panic net/core/skbuff.c:109 [inline]
  skb_put+0x181/0x1c0 net/core/skbuff.c:1694
  add_grhead.isra.24+0x42/0x3b0 net/ipv6/mcast.c:1695
  add_grec+0xa55/0x1060 net/ipv6/mcast.c:1817
  mld_send_cr net/ipv6/mcast.c:1903 [inline]
  mld_ifc_timer_expire+0x4d2/0x770 net/ipv6/mcast.c:2448
  call_timer_fn+0x23b/0x840 kernel/time/timer.c:1320
  expire_timers kernel/time/timer.c:1357 [inline]
  __run_timers+0x7e1/0xb60 kernel/time/timer.c:1660
  run_timer_softirq+0x4c/0xb0 kernel/time/timer.c:1686
  __do_softirq+0x29d/0xbb2 kernel/softirq.c:285
  invoke_softirq kernel/softirq.c:365 [inline]
  irq_exit+0x1d3/0x210 kernel/softirq.c:405
  exiting_irq arch/x86/include/asm/apic.h:540 [inline]
  smp_apic_timer_interrupt+0x16b/0x700 arch/x86/kernel/apic/apic.c:1052
  apic_timer_interrupt+0xa9/0xb0 arch/x86/entry/entry_64.S:920

Signed-off-by: Eric Dumazet 
Reported-by: syzbot 
Tested-by: Xin Long 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

ipv4: igmp: guard against silly MTU values

2018-01-02T19:04:58+00:00

[ Upstream commit b5476022bbada3764609368f03329ca287528dc8 ]

IPv4 stack reacts to changes to small MTU, by disabling itself under
RTNL.

But there is a window where threads not using RTNL can see a wrong
device mtu. This can lead to surprises, in igmp code where it is
assumed the mtu is suitable.

Fix this by reading device mtu once and checking IPv4 minimal MTU.

This patch adds missing IPV4_MIN_MTU define, to not abuse
ETH_MIN_MTU anymore.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

netfilter: nf_nat_snmp: Fix panic when snmp_trap_helper fails to register

2017-12-25T13:20:08+00:00

[ Upstream commit 75c689dca98851d65ef5a27e5ce26b625b68751c ]

In the commit 93557f53e1fb ("netfilter: nf_conntrack: nf_conntrack snmp
helper"), the snmp_helper is replaced by nf_nat_snmp_hook. So the
snmp_helper is never registered. But it still tries to unregister the
snmp_helper, it could cause the panic.

Now remove the useless snmp_helper and the unregister call in the
error handler.

Fixes: 93557f53e1fb ("netfilter: nf_conntrack: nf_conntrack snmp helper")
Signed-off-by: Gao Feng 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

netfilter: nfnl_cthelper: fix a race when walk the nf_ct_helper_hash table

2017-12-25T13:20:08+00:00

[ Upstream commit 83d90219a5df8d950855ce73229a97b63605c317 ]

The nf_ct_helper_hash table is protected by nf_ct_helper_mutex, while
nfct_helper operation is protected by nfnl_lock(NFNL_SUBSYS_CTHELPER).
So it's possible that one CPU is walking the nf_ct_helper_hash for
cthelper add/get/del, another cpu is doing nf_conntrack_helpers_unregister
at the same time. This is dangrous, and may cause use after free error.

Note, delete operation will flush all cthelpers added via nfnetlink, so
using rcu to do protect is not easy.

Now introduce a dummy list to record all the cthelpers added via
nfnetlink, then we can walk the dummy list instead of walking the
nf_ct_helper_hash. Also, keep nfnl_cthelper_dump_table unchanged, it
may be invoked without nfnl_lock(NFNL_SUBSYS_CTHELPER) held.

Signed-off-by: Liping Zhang 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

net: Do not allow negative values for busy_read and busy_poll sysctl interfaces

2017-12-25T13:20:07+00:00

[ Upstream commit 95f255211396958c718aef8c45e3923b5211ea7b ]

This change basically codifies what I think was already the limitations on
the busy_poll and busy_read sysctl interfaces.  We weren't checking the
lower bounds and as such could input negative values. The behavior when
that was used was dependent on the architecture. In order to prevent any
issues with that I am just disabling support for values less than 0 since
this way we don't have to worry about any odd behaviors.

By limiting the sysctl values this way it also makes it consistent with how
we handle the SO_BUSY_POLL socket option since the value appears to be
reported as a signed integer value and negative values are rejected.

Signed-off-by: Alexander Duyck 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman