linux.git/net/ipv6, branch v4.16-rc4

ipv6 sit: work around bogus gcc-8 -Wrestrict warning

2018-02-23T15:53:26+00:00

gcc-8 has a new warning that detects overlapping input and output arguments
in memcpy(). It triggers for sit_init_net() calling ipip6_tunnel_clone_6rd(),
which is actually correct:

net/ipv6/sit.c: In function 'sit_init_net':
net/ipv6/sit.c:192:3: error: 'memcpy' source argument is the same as destination [-Werror=restrict]

The problem here is that the logic detecting the memcpy() arguments finds them
to be the same, but the conditional that tests for the input and output of
ipip6_tunnel_clone_6rd() to be identical is not a compile-time constant.

We know that netdev_priv(t->dev) is the same as t for a tunnel device,
and comparing "dev" directly here lets the compiler figure out as well
that 'dev == sitn->fb_tunnel_dev' when called from sit_init_net(), so
it no longer warns.

This code is old, so Cc stable to make sure that we don't get the warning
for older kernels built with new gcc.

Cc: Martin Sebor 
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83456
Signed-off-by: Arnd Bergmann 
Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf

2018-02-21T19:49:55+00:00

Pablo Neira Ayuso says:

====================
Netfilter fixes for net

The following patchset contains large batch with Netfilter fixes for
your net tree, mostly due to syzbot report fixups and pr_err()
ratelimiting, more specifically, they are:

1) Get rid of superfluous unnecessary check in x_tables before vmalloc(),
   we don't hit BUG there anymore, patch from Michal Hock, suggested by
   Andrew Morton.

2) Race condition in proc file creation in ipt_CLUSTERIP, from Cong Wang.

3) Drop socket lock that results in circular locking dependency, patch
   from Paolo Abeni.

4) Drop packet if case of malformed blob that makes backpointer jump
   in x_tables, from Florian Westphal.

5) Fix refcount leak due to race in ipt_CLUSTERIP in
   clusterip_config_find_get(), from Cong Wang.

6) Several patches to ratelimit pr_err() for x_tables since this can be
   a problem where CAP_NET_ADMIN semantics can protect us in untrusted
   namespace, from Florian Westphal.

7) Missing .gitignore update for new autogenerated asn1 state machine
   for the SNMP NAT helper, from Zhu Lingshan.

8) Missing timer initialization in xt_LED, from Paolo Abeni.

9) Do not allow negative port range in NAT, also from Paolo.

10) Lock imbalance in the xt_hashlimit rate match mode, patch from
    Eric Dumazet.

11) Initialize workqueue before timer in the idletimer match,
    from Eric Dumazet.
====================

Signed-off-by: David S. Miller

udplite: fix partial checksum initialization

2018-02-16T20:57:42+00:00

Since UDP-Lite is always using checksum, the following path is
triggered when calculating pseudo header for it:

  udp4_csum_init() or udp6_csum_init()
    skb_checksum_init_zero_check()
      __skb_checksum_validate_complete()

The problem can appear if skb->len is less than CHECKSUM_BREAK. In
this particular case __skb_checksum_validate_complete() also invokes
__skb_checksum_complete(skb). If UDP-Lite is using partial checksum
that covers only part of a packet, the function will return bad
checksum and the packet will be dropped.

It can be fixed if we skip skb_checksum_init_zero_check() and only
set the required pseudo header checksum for UDP-Lite with partial
checksum before udp4_csum_init()/udp6_csum_init() functions return.

Fixes: ed70fcfcee95 ("net: Call skb_checksum_init in IPv4")
Fixes: e4f45b7f40bd ("net: Call skb_checksum_init in IPv6")
Signed-off-by: Alexey Kodanev 
Signed-off-by: David S. Miller

netfilter: x_tables: use pr ratelimiting in all remaining spots

2018-02-14T20:05:38+00:00

Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso

netfilter: x_tables: rate-limit table mismatch warnings

2018-02-14T20:05:36+00:00

Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso

netfilter: add back stackpointer size checks

2018-02-14T19:47:41+00:00

The rationale for removing the check is only correct for rulesets
generated by ip(6)tables.

In iptables, a jump can only occur to a user-defined chain, i.e.
because we size the stack based on number of user-defined chains we
cannot exceed stack size.

However, the underlying binary format has no such restriction,
and the validation step only ensures that the jump target is a
valid rule start point.

IOW, its possible to build a rule blob that has no user-defined
chains but does contain a jump.

If this happens, no jump stack gets allocated and crash occurs
because no jumpstack was allocated.

Fixes: 7814b6ec6d0d6 ("netfilter: xtables: don't save/restore jumpstack offset")
Reported-by: syzbot+e783f671527912cd9403@syzkaller.appspotmail.com
Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso

netfilter: drop outermost socket lock in getsockopt()

2018-02-14T19:44:42+00:00

The Syzbot reported a possible deadlock in the netfilter area caused by
rtnl lock, xt lock and socket lock being acquired with a different order
on different code paths, leading to the following backtrace:
Reviewed-by: Xin Long 

======================================================
WARNING: possible circular locking dependency detected
4.15.0+ #301 Not tainted
------------------------------------------------------
syzkaller233489/4179 is trying to acquire lock:
  (rtnl_mutex){+.+.}, at: [<0000000048e996fd>] rtnl_lock+0x17/0x20
net/core/rtnetlink.c:74

but task is already holding lock:
  (&xt[i].mutex){+.+.}, at: [<00000000328553a2>]
xt_find_table_lock+0x3e/0x3e0 net/netfilter/x_tables.c:1041

which lock already depends on the new lock.
===

Since commit 3f34cfae1230 ("netfilter: on sockopt() acquire sock lock
only in the required scope"), we already acquire the socket lock in
the innermost scope, where needed. In such commit I forgot to remove
the outer-most socket lock from the getsockopt() path, this commit
addresses the issues dropping it now.

v1 -> v2: fix bad subj, added relavant 'fixes' tag

Fixes: 22265a5c3c10 ("netfilter: xt_TEE: resolve oif using netdevice notifiers")
Fixes: 202f59afd441 ("netfilter: ipt_CLUSTERIP: do not hold dev")
Fixes: 3f34cfae1230 ("netfilter: on sockopt() acquire sock lock only in the required scope")
Reported-by: syzbot+ddde1c7b7ff7442d7f2d@syzkaller.appspotmail.com
Suggested-by: Florian Westphal 
Signed-off-by: Paolo Abeni 
Signed-off-by: Pablo Neira Ayuso

tcp: tracepoint: only call trace_tcp_send_reset with full socket

2018-02-08T03:00:42+00:00

tracepoint tcp_send_reset requires a full socket to work. However, it
may be called when in TCP_TIME_WAIT:

        case TCP_TW_RST:
                tcp_v6_send_reset(sk, skb);
                inet_twsk_deschedule_put(inet_twsk(sk));
                goto discard_it;

To avoid this problem, this patch checks the socket with sk_fullsock()
before calling trace_tcp_send_reset().

Fixes: c24b14c46bb8 ("tcp: add tracepoint trace_tcp_send_reset")
Signed-off-by: Song Liu 
Reviewed-by: Lawrence Brakmo 
Signed-off-by: David S. Miller

net/ipv6: onlink nexthop checks should default to main table

2018-02-08T02:52:42+00:00

Because of differences in how ipv4 and ipv6 handle fib lookups,
verification of nexthops with onlink flag need to default to the main
table rather than the local table used by IPv4. As it stands an
address within a connected route on device 1 can be used with
onlink on device 2. Updating the table properly rejects the route
due to the egress device mismatch.

Update the extack message as well to show it could be a device
mismatch for the nexthop spec.

Fixes: fc1e64e1092f ("net/ipv6: Add support for onlink flag")
Signed-off-by: David Ahern 
Signed-off-by: David S. Miller

net/ipv6: Handle reject routes with onlink flag

2018-02-08T02:52:06+00:00

Verification of nexthops with onlink flag need to handle unreachable
routes. The lookup is only intended to validate the gateway address
is not a local address and if the gateway resolves the egress device
must match the given device. Hence, hitting any default reject route
is ok.

Fixes: fc1e64e1092f ("net/ipv6: Add support for onlink flag")
Signed-off-by: David Ahern 
Signed-off-by: David S. Miller