linux-stable.git/net/ipv4/route.c, branch linux-4.8.y

ipv4: use new_gw for redirect neigh lookup

2016-11-21T09:11:36+00:00

[ Upstream commit 969447f226b451c453ddc83cac6144eaeac6f2e3 ]

In v2.6, ip_rt_redirect() calls arp_bind_neighbour() which returns 0
and then the state of the neigh for the new_gw is checked. If the state
isn't valid then the redirected route is deleted. This behavior is
maintained up to v3.5.7 by check_peer_redirect() because rt->rt_gateway
is assigned to peer->redirect_learned.a4 before calling
ipv4_neigh_lookup().

After commit 5943634fc559 ("ipv4: Maintain redirect and PMTU info in
struct rtable again."), ipv4_neigh_lookup() is performed without the
rt_gateway assigned to the new_gw. In the case when rt_gateway (old_gw)
isn't zero, the function uses it as the key. The neigh is most likely
valid since the old_gw is the one that sends the ICMP redirect message.
Then the new_gw is assigned to fib_nh_exception. The problem is: the
new_gw ARP may never gets resolved and the traffic is blackholed.

So, use the new_gw for neigh lookup.

Changes from v1:
 - use __ipv4_neigh_lookup instead (per Eric Dumazet).

Fixes: 5943634fc559 ("ipv4: Maintain redirect and PMTU info in struct rtable again.")
Signed-off-by: Stephen Suryaputra Lin 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

ipmr, ip6mr: fix scheduling while atomic and a deadlock with ipmr_get_route

2016-09-26T03:41:39+00:00

Since the commit below the ipmr/ip6mr rtnl_unicast() code uses the portid
instead of the previous dst_pid which was copied from in_skb's portid.
Since the skb is new the portid is 0 at that point so the packets are sent
to the kernel and we get scheduling while atomic or a deadlock (depending
on where it happens) by trying to acquire rtnl two times.
Also since this is RTM_GETROUTE, it can be triggered by a normal user.

Here's the sleeping while atomic trace:
[ 7858.212557] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:620
[ 7858.212748] in_atomic(): 1, irqs_disabled(): 0, pid: 0, name: swapper/0
[ 7858.212881] 2 locks held by swapper/0/0:
[ 7858.213013]  #0:  (((&mrt->ipmr_expire_timer))){+.-...}, at: [] call_timer_fn+0x5/0x350
[ 7858.213422]  #1:  (mfc_unres_lock){+.....}, at: [] ipmr_expire_process+0x25/0x130
[ 7858.213807] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.8.0-rc7+ #179
[ 7858.213934] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014
[ 7858.214108]  0000000000000000 ffff88005b403c50 ffffffff813a7804 0000000000000000
[ 7858.214412]  ffffffff81a1338e ffff88005b403c78 ffffffff810a4a72 ffffffff81a1338e
[ 7858.214716]  000000000000026c 0000000000000000 ffff88005b403ca8 ffffffff810a4b9f
[ 7858.215251] Call Trace:
[ 7858.215412]    [] dump_stack+0x85/0xc1
[ 7858.215662]  [] ___might_sleep+0x192/0x250
[ 7858.215868]  [] __might_sleep+0x6f/0x100
[ 7858.216072]  [] mutex_lock_nested+0x33/0x4d0
[ 7858.216279]  [] ? netlink_lookup+0x25f/0x460
[ 7858.216487]  [] rtnetlink_rcv+0x1b/0x40
[ 7858.216687]  [] netlink_unicast+0x19c/0x260
[ 7858.216900]  [] rtnl_unicast+0x20/0x30
[ 7858.217128]  [] ipmr_destroy_unres+0xa9/0xf0
[ 7858.217351]  [] ipmr_expire_process+0x8f/0x130
[ 7858.217581]  [] ? ipmr_net_init+0x180/0x180
[ 7858.217785]  [] ? ipmr_net_init+0x180/0x180
[ 7858.217990]  [] call_timer_fn+0xa5/0x350
[ 7858.218192]  [] ? call_timer_fn+0x5/0x350
[ 7858.218415]  [] ? ipmr_net_init+0x180/0x180
[ 7858.218656]  [] run_timer_softirq+0x260/0x640
[ 7858.218865]  [] ? __do_softirq+0xbb/0x54f
[ 7858.219068]  [] __do_softirq+0xe8/0x54f
[ 7858.219269]  [] irq_exit+0xb8/0xc0
[ 7858.219463]  [] smp_apic_timer_interrupt+0x42/0x50
[ 7858.219678]  [] apic_timer_interrupt+0x8c/0xa0
[ 7858.219897]    [] ? native_safe_halt+0x6/0x10
[ 7858.220165]  [] ? trace_hardirqs_on+0xd/0x10
[ 7858.220373]  [] default_idle+0x23/0x190
[ 7858.220574]  [] arch_cpu_idle+0xf/0x20
[ 7858.220790]  [] default_idle_call+0x4c/0x60
[ 7858.221016]  [] cpu_startup_entry+0x39b/0x4d0
[ 7858.221257]  [] rest_init+0x135/0x140
[ 7858.221469]  [] start_kernel+0x50e/0x51b
[ 7858.221670]  [] ? early_idt_handler_array+0x120/0x120
[ 7858.221894]  [] x86_64_start_reservations+0x2a/0x2c
[ 7858.222113]  [] x86_64_start_kernel+0x13b/0x14a

Fixes: 2942e9005056 ("[RTNETLINK]: Use rtnl_unicast() for rtnetlink unicasts")
Signed-off-by: Nikolay Aleksandrov 
Signed-off-by: David S. Miller

net: get rid of an signed integer overflow in ip_idents_reserve()

2016-09-22T06:41:17+00:00

Jiri Pirko reported an UBSAN warning happening in ip_idents_reserve()

[] UBSAN: Undefined behaviour in ./arch/x86/include/asm/atomic.h:156:11
[] signed integer overflow:
[] -2117905507 + -695755206 cannot be represented in type 'int'

Since we do not have uatomic_add_return() yet, use atomic_cmpxchg()
so that the arithmetics can be done using unsigned int.

Fixes: 04ca6973f7c1 ("ip: make IP identifiers less predictable")
Signed-off-by: Eric Dumazet 
Reported-by: Jiri Pirko 
Signed-off-by: David S. Miller

net: l3mdev: Allow send on enslaved interface

2016-05-10T02:33:52+00:00

Allow udp and raw sockets to send by oif that is an enslaved interface
versus the l3mdev/VRF device. For example, this allows BFD to use ifindex
from IP_PKTINFO on a receive to send a response without the need to
convert to the VRF index. It also allows ping and ping6 to work when
specifying an enslaved interface (e.g., ping -I swp1 ) which is
a natural use case.

Signed-off-by: David Ahern 
Signed-off-by: David S. Miller

net: rename IP_INC_STATS_BH()

2016-04-28T02:48:23+00:00

Rename IP_INC_STATS_BH() to __IP_INC_STATS(), to
better express this is used in non preemptible context.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

route: do not cache fib route info on local routes with oif

2016-04-14T03:33:01+00:00

For local routes that require a particular output interface we do not want
to cache the result.  Caching the result causes incorrect behaviour when
there are multiple source addresses on the interface.  The end result
being that if the intended recipient is waiting on that interface for the
packet he won't receive it because it will be delivered on the loopback
interface and the IP_PKTINFO ipi_ifindex will be set to the loopback
interface as well.

This can be tested by running a program such as "dhcp_release" which
attempts to inject a packet on a particular interface so that it is
received by another program on the same board.  The receiving process
should see an IP_PKTINFO ipi_ifndex value of the source interface
(e.g., eth1) instead of the loopback interface (e.g., lo).  The packet
will still appear on the loopback interface in tcpdump but the important
aspect is that the CMSG info is correct.

Sample dhcp_release command line:

   dhcp_release eth1 192.168.204.222 02:11:33:22:44:66

Signed-off-by: Allain Legacy 
Signed off-by: Chris Friesen 
Reviewed-by: Julian Anastasov 
Signed-off-by: David S. Miller

net: vrf: Fix dst reference counting

2016-04-11T19:56:20+00:00

Vivek reported a kernel exception deleting a VRF with an active
connection through it. The root cause is that the socket has a cached
reference to a dst that is destroyed. Converting the dst_destroy to
dst_release and letting proper reference counting kick in does not
work as the dst has a reference to the device which needs to be released
as well.

I talked to Hannes about this at netdev and he pointed out the ipv4 and
ipv6 dst handling has dst_ifdown for just this scenario. Rather than
continuing with the reinvented dst wheel in VRF just remove it and
leverage the ipv4 and ipv6 versions.

Fixes: 193125dbd8eb2 ("net: Introduce VRF device driver")
Fixes: 35402e3136634 ("net: Add IPv6 support to VRF device")

Signed-off-by: David Ahern 
Signed-off-by: David S. Miller

route: check and remove route cache when we get route

2016-02-18T16:31:36+00:00

Since the gc of ipv4 route was removed, the route cached would has
no chance to be removed, and even it has been timeout, it still could
be used, cause no code to check it's expires.

Fix this issue by checking  and removing route cache when we get route.

Signed-off-by: Xin Long 
Acked-by: Hannes Frederic Sowa 
Signed-off-by: David S. Miller

net: Do not drop to make_route if oif is l3mdev

2015-10-08T12:18:47+00:00

Commit deaa0a6a930 ("net: Lookup actual route when oif is VRF device")
exposed a bug in __ip_route_output_key_hash for VRF devices: on FIB lookup
failure if the oif is specified the current logic drops to make_route on
the assumption that the route tables are wrong. For VRF/L3 master devices
this leads to wrong dst entries and route lookups. For example:
    $ ip route ls table vrf-red
    unreachable default
    broadcast 10.2.1.0 dev eth1  proto kernel  scope link  src 10.2.1.2
    10.2.1.0/24 dev eth1  proto kernel  scope link  src 10.2.1.2
    local 10.2.1.2 dev eth1  proto kernel  scope host  src 10.2.1.2
    broadcast 10.2.1.255 dev eth1  proto kernel  scope link  src 10.2.1.2

    $ ip route get oif vrf-red 1.1.1.1
    1.1.1.1 dev vrf-red  src 10.0.0.2
        cache

With this patch:
    $  ip route get oif vrf-red 1.1.1.1
    RTNETLINK answers: No route to host

which is the correct response based on the default route

Signed-off-by: David Ahern 
Signed-off-by: David S. Miller

dst: Pass net into dst->output

2015-10-08T11:27:03+00:00

The network namespace is already passed into dst_output pass it into
dst->output lwt->output and friends.

Signed-off-by: "Eric W. Biederman" 
Signed-off-by: David S. Miller