linux-stable.git/net/ipv6, branch v3.2.85

tcp: take care of truncations done by sk_filter()

2017-02-23T03:51:05+00:00

commit ac6e780070e30e4c35bd395acfe9191e6268bdd3 upstream.

With syzkaller help, Marco Grassi found a bug in TCP stack,
crashing in tcp_collapse()

Root cause is that sk_filter() can truncate the incoming skb,
but TCP stack was not really expecting this to happen.
It probably was expecting a simple DROP or ACCEPT behavior.

We first need to make sure no part of TCP header could be removed.
Then we need to adjust TCP_SKB_CB(skb)->end_seq

Many thanks to syzkaller team and Marco for giving us a reproducer.

Signed-off-by: Eric Dumazet 
Reported-by: Marco Grassi 
Reported-by: Vladis Dronov 
Signed-off-by: David S. Miller 
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings

ip6_tunnel: Clear IP6CB in ip6tunnel_xmit()

2017-02-23T03:50:58+00:00

commit 23f4ffedb7d751c7e298732ba91ca75d224bc1a6 upstream.

skb->cb may contain data from previous layers. In the observed scenario,
the garbage data were misinterpreted as IP6CB(skb)->frag_max_size, so
that small packets sent through the tunnel are mistakenly fragmented.

This patch unconditionally clears the control buffer in ip6tunnel_xmit(),
which affects ip6_tunnel, ip6_udp_tunnel and ip6_gre. Currently none of
these tunnels set IP6CB(skb)->flags, otherwise it needs to be done earlier.

Signed-off-by: Eli Cooper 
Signed-off-by: David S. Miller 
[bwh: Backported to 3.2: apply to ip6_tnl_xmit2()]
Signed-off-by: Ben Hutchings

ipv6: Don't use ufo handling on later transformed packets

2017-02-23T03:50:57+00:00

commit f89c56ce710afa65e1b2ead555b52c4807f34ff7 upstream.

Similar to commit c146066ab802 ("ipv4: Don't use ufo handling on later
transformed packets"), don't perform UFO on packets that will be IPsec
transformed. To detect it we rely on the fact that headerlen in
dst_entry is non-zero only for transformation bundles (xfrm_dst
objects).

Unwanted segmentation can be observed with a NETIF_F_UFO capable device,
such as a dummy device:

  DEV=dum0 LEN=1493

  ip li add $DEV type dummy
  ip addr add fc00::1/64 dev $DEV nodad
  ip link set $DEV up
  ip xfrm policy add dir out src fc00::1 dst fc00::2 \
     tmpl src fc00::1 dst fc00::2 proto esp spi 1
  ip xfrm state add src fc00::1 dst fc00::2 \
     proto esp spi 1 enc 'aes' 0x0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b

  tcpdump -n -nn -i $DEV -t &
  socat /dev/zero,readbytes=$LEN udp6:[fc00::2]:$LEN

tcpdump output before:

  IP6 fc00::1 > fc00::2: frag (0|1448) ESP(spi=0x00000001,seq=0x1), length 1448
  IP6 fc00::1 > fc00::2: frag (1448|48)
  IP6 fc00::1 > fc00::2: ESP(spi=0x00000001,seq=0x2), length 88

... and after:

  IP6 fc00::1 > fc00::2: frag (0|1448) ESP(spi=0x00000001,seq=0x1), length 1448
  IP6 fc00::1 > fc00::2: frag (1448|80)

Fixes: e89e9cf539a2 ("[IPv4/IPv6]: UFO Scatter-gather approach")

Signed-off-by: Jakub Sitnicki 
Acked-by: Hannes Frederic Sowa 
Signed-off-by: David S. Miller 
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings

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

2016-11-20T01:01:42+00:00

commit 2cf750704bb6d7ed8c7d732e071dd1bc890ea5e8 upstream.

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 
[bwh: Backported to 3.2:
 - Use 'pid' instead of 'portid' where necessary
 - Adjust context]
Signed-off-by: Ben Hutchings

netfilter: x_tables: fix unconditional helper

2016-04-30T22:05:28+00:00

commit 54d83fc74aa9ec72794373cb47432c5f7fb1a309 upstream.

Ben Hawkes says:

 In the mark_source_chains function (net/ipv4/netfilter/ip_tables.c) it
 is possible for a user-supplied ipt_entry structure to have a large
 next_offset field. This field is not bounds checked prior to writing a
 counter value at the supplied offset.

Problem is that mark_source_chains should not have been called --
the rule doesn't have a next entry, so its supposed to return
an absolute verdict of either ACCEPT or DROP.

However, the function conditional() doesn't work as the name implies.
It only checks that the rule is using wildcard address matching.

However, an unconditional rule must also not be using any matches
(no -m args).

The underflow validator only checked the addresses, therefore
passing the 'unconditional absolute verdict' test, while
mark_source_chains also tested for presence of matches, and thus
proceeeded to the next (not-existent) rule.

Unify this so that all the callers have same idea of 'unconditional rule'.

Reported-by: Ben Hawkes 
Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Ben Hutchings

ipv6: Count in extension headers in skb->network_header

2016-04-30T22:05:27+00:00

[ Upstream commit 3ba3458fb9c050718b95275a3310b74415e767e2 ]

When sending a UDPv6 message longer than MTU, account for the length
of fragmentable IPv6 extension headers in skb->network_header offset.
Same as we do in alloc_new_skb path in __ip6_append_data().

This ensures that later on __ip6_make_skb() will make space in
headroom for fragmentable extension headers:

	/* move skb->data to ip header from ext header */
	if (skb->data < skb_network_header(skb))
		__skb_pull(skb, skb_network_offset(skb));

Prevents a splat due to skb_under_panic:

skbuff: skb_under_panic: text:ffffffff8143397b len:2126 put:14 \
head:ffff880005bacf50 data:ffff880005bacf4a tail:0x48 end:0xc0 dev:lo
------------[ cut here ]------------
kernel BUG at net/core/skbuff.c:104!
invalid opcode: 0000 [#1] KASAN
CPU: 0 PID: 160 Comm: reproducer Not tainted 4.6.0-rc2 #65
[...]
Call Trace:
 [] skb_push+0x79/0x80
 [] eth_header+0x2b/0x100
 [] neigh_resolve_output+0x210/0x310
 [] ip6_finish_output2+0x4a7/0x7c0
 [] ip6_output+0x16a/0x280
 [] ip6_local_out+0xb1/0xf0
 [] ip6_send_skb+0x45/0xd0
 [] udp_v6_send_skb+0x246/0x5d0
 [] udpv6_sendmsg+0xa6e/0x1090
[...]

Reported-by: Ji Jianwen 
Signed-off-by: Jakub Sitnicki 
Acked-by: Hannes Frederic Sowa 
Signed-off-by: David S. Miller 
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings

net/ipv6: add sysctl option accept_ra_min_hop_limit

2016-04-30T22:05:25+00:00

[ Upstream commit 8013d1d7eafb0589ca766db6b74026f76b7f5cb4 ]

Commit 6fd99094de2b ("ipv6: Don't reduce hop limit for an interface")
disabled accept hop limit from RA if it is smaller than the current hop
limit for security stuff. But this behavior kind of break the RFC definition.

RFC 4861, 6.3.4.  Processing Received Router Advertisements
   A Router Advertisement field (e.g., Cur Hop Limit, Reachable Time,
   and Retrans Timer) may contain a value denoting that it is
   unspecified.  In such cases, the parameter should be ignored and the
   host should continue using whatever value it is already using.

   If the received Cur Hop Limit value is non-zero, the host SHOULD set
   its CurHopLimit variable to the received value.

So add sysctl option accept_ra_min_hop_limit to let user choose the minimum
hop limit value they can accept from RA. And set default to 1 to meet RFC
standards.

Signed-off-by: Hangbin Liu 
Acked-by: YOSHIFUJI Hideaki 
Signed-off-by: David S. Miller 
[bwh: Backported to 3.2:
 - Adjust filename, context
 - Number DEVCONF enumerators explicitly to match upstream]
Signed-off-by: Ben Hutchings

ipv6/udp: use sticky pktinfo egress ifindex on connect()

2016-04-30T22:05:25+00:00

[ Upstream commit 1cdda91871470f15e79375991bd2eddc6e86ddb1 ]

Currently, the egress interface index specified via IPV6_PKTINFO
is ignored by __ip6_datagram_connect(), so that RFC 3542 section 6.7
can be subverted when the user space application calls connect()
before sendmsg().
Fix it by initializing properly flowi6_oif in connect() before
performing the route lookup.

Signed-off-by: Paolo Abeni 
Acked-by: Hannes Frederic Sowa 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

ipv6: update skb->csum when CE mark is propagated

2016-04-30T22:05:25+00:00

[ Upstream commit 34ae6a1aa0540f0f781dd265366036355fdc8930 ]

When a tunnel decapsulates the outer header, it has to comply
with RFC 6080 and eventually propagate CE mark into inner header.

It turns out IP6_ECN_set_ce() does not correctly update skb->csum
for CHECKSUM_COMPLETE packets, triggering infamous "hw csum failure"
messages and stack traces.

Signed-off-by: Eric Dumazet 
Acked-by: Herbert Xu 
Signed-off-by: David S. Miller 
[bwh: Backported to 3.2:
 - Adjust context
 - Add skb argument to other callers of IP6_ECN_set_ce()]
Signed-off-by: Ben Hutchings

netfilter: x_tables: make sure e->next_offset covers remaining blob size

2016-04-30T22:05:23+00:00

commit 6e94e0cfb0887e4013b3b930fa6ab1fe6bb6ba91 upstream.

Otherwise this function may read data beyond the ruleset blob.

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