linux-stable.git/net/ipv6, branch v3.12.52

net: fix IP early demux races

2016-01-05T17:18:01+00:00

[ Upstream commit 5037e9ef9454917b047f9f3a19b4dd179fbf7cd4 ]

David Wilder reported crashes caused by dst reuse.


  I am seeing a crash on a distro V4.2.3 kernel caused by a double
  release of a dst_entry.  In ipv4_dst_destroy() the call to
  list_empty() finds a poisoned next pointer, indicating the dst_entry
  has already been removed from the list and freed. The crash occurs
  18 to 24 hours into a run of a network stress exerciser.


Thanks to his detailed report and analysis, we were able to understand
the core issue.

IP early demux can associate a dst to skb, after a lookup in TCP/UDP
sockets.

When socket cache is not properly set, we want to store into
sk->sk_dst_cache the dst for future IP early demux lookups,
by acquiring a stable refcount on the dst.

Problem is this acquisition is simply using an atomic_inc(),
which works well, unless the dst was queued for destruction from
dst_release() noticing dst refcount went to zero, if DST_NOCACHE
was set on dst.

We need to make sure current refcount is not zero before incrementing
it, or risk double free as David reported.

This patch, being a stable candidate, adds two new helpers, and use
them only from IP early demux problematic paths.

It might be possible to merge in net-next skb_dst_force() and
skb_dst_force_safe(), but I prefer having the smallest patch for stable
kernels : Maybe some skb_dst_force() callers do not expect skb->dst
can suddenly be cleared.

Can probably be backported back to linux-3.6 kernels

Reported-by: David J. Wilder 
Tested-by: David J. Wilder 
Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Jiri Slaby

net: add validation for the socket syscall protocol argument

2016-01-05T17:04:00+00:00

[ Upstream commit 79462ad02e861803b3840cc782248c7359451cd9 ]

郭永刚 reported that one could simply crash the kernel as root by
using a simple program:

	int socket_fd;
	struct sockaddr_in addr;
	addr.sin_port = 0;
	addr.sin_addr.s_addr = INADDR_ANY;
	addr.sin_family = 10;

	socket_fd = socket(10,3,0x40000000);
	connect(socket_fd , &addr,16);

AF_INET, AF_INET6 sockets actually only support 8-bit protocol
identifiers. inet_sock's skc_protocol field thus is sized accordingly,
thus larger protocol identifiers simply cut off the higher bits and
store a zero in the protocol fields.

This could lead to e.g. NULL function pointer because as a result of
the cut off inet_num is zero and we call down to inet_autobind, which
is NULL for raw sockets.

kernel: Call Trace:
kernel:  [] ? inet_autobind+0x2e/0x70
kernel:  [] inet_dgram_connect+0x54/0x80
kernel:  [] SYSC_connect+0xd9/0x110
kernel:  [] ? ptrace_notify+0x5b/0x80
kernel:  [] ? syscall_trace_enter_phase2+0x108/0x200
kernel:  [] SyS_connect+0xe/0x10
kernel:  [] tracesys_phase2+0x84/0x89

I found no particular commit which introduced this problem.

CVE: CVE-2015-8543
Cc: Cong Wang 
Reported-by: 郭永刚 
Signed-off-by: Hannes Frederic Sowa 
Signed-off-by: David S. Miller 
Signed-off-by: Jiri Slaby

gre6: allow to update all parameters via rtnl

2016-01-05T16:55:53+00:00

[ Upstream commit 6a61d4dbf4f54b5683e0f1e58d873cecca7cb977 ]

Parameters were updated only if the kernel was unable to find the tunnel
with the new parameters, ie only if core pamareters were updated (keys,
addr, link, type).
Now it's possible to update ttl, hoplimit, flowinfo and flags.

Fixes: c12b395a4664 ("gre: Support GRE over IPv6")
Signed-off-by: Nicolas Dichtel 
Signed-off-by: David S. Miller 
Signed-off-by: Jiri Slaby

ip6mr: call del_timer_sync() in ip6mr_free_table()

2016-01-05T16:48:05+00:00

commit 7ba0c47c34a1ea5bc7a24ca67309996cce0569b5 upstream.

We need to wait for the flying timers, since we
are going to free the mrtable right after it.

Cc: Hannes Frederic Sowa 
Signed-off-by: Cong Wang 
Signed-off-by: David S. Miller 
Cc: Ben Hutchings 
Signed-off-by: Jiri Slaby

netfilter: ip6t_SYNPROXY: fix NULL pointer dereference

2016-01-05T16:01:29+00:00

commit 96fffb4f23f124f297d51dedc9cf51d19eb88ee1 upstream.

This happens when networking namespaces are enabled.

Suggested-by: Patrick McHardy 
Signed-off-by: Phil Sutter 
Acked-by: Patrick McHardy 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Jiri Slaby

ipv6: add complete rcu protection around np->opt

2016-01-05T15:11:14+00:00

[ Upstream commit 45f6fad84cc305103b28d73482b344d7f5b76f39 ]

This patch addresses multiple problems :

UDP/RAW sendmsg() need to get a stable struct ipv6_txoptions
while socket is not locked : Other threads can change np->opt
concurrently. Dmitry posted a syzkaller
(http://github.com/google/syzkaller) program desmonstrating
use-after-free.

Starting with TCP/DCCP lockless listeners, tcp_v6_syn_recv_sock()
and dccp_v6_request_recv_sock() also need to use RCU protection
to dereference np->opt once (before calling ipv6_dup_options())

This patch adds full RCU protection to np->opt

Reported-by: Dmitry Vyukov 
Signed-off-by: Eric Dumazet 
Acked-by: Hannes Frederic Sowa 
Signed-off-by: David S. Miller 
Signed-off-by: Jiri Slaby

ipv6: distinguish frag queues by device for multicast and link-local packets

2016-01-05T15:11:13+00:00

[ Upstream commit 264640fc2c5f4f913db5c73fa3eb1ead2c45e9d7 ]

If a fragmented multicast packet is received on an ethernet device which
has an active macvlan on top of it, each fragment is duplicated and
received both on the underlying device and the macvlan. If some
fragments for macvlan are processed before the whole packet for the
underlying device is reassembled, the "overlapping fragments" test in
ip6_frag_queue() discards the whole fragment queue.

To resolve this, add device ifindex to the search key and require it to
match reassembling multicast packets and packets to link-local
addresses.

Note: similar patch has been already submitted by Yoshifuji Hideaki in

  http://patchwork.ozlabs.org/patch/220979/

but got lost and forgotten for some reason.

Signed-off-by: Michal Kubecek 
Signed-off-by: David S. Miller 
Signed-off-by: Jiri Slaby

net: ip6mr: fix static mfc/dev leaks on table destruction

2016-01-05T15:11:12+00:00

[ Upstream commit 4c6980462f32b4f282c5d8e5f7ea8070e2937725 ]

Similar to ipv4, when destroying an mrt table the static mfc entries and
the static devices are kept, which leads to devices that can never be
destroyed (because of refcnt taken) and leaked memory. Make sure that
everything is cleaned up on netns destruction.

Fixes: 8229efdaef1e ("netns: ip6mr: enable namespace support in ipv6 multicast forwarding code")
CC: Benjamin Thery 
Signed-off-by: Nikolay Aleksandrov 
Reviewed-by: Cong Wang 
Signed-off-by: David S. Miller 
Signed-off-by: Jiri Slaby

snmp: Remove duplicate OUTMCAST stat increment

2016-01-05T15:11:09+00:00

[ Upstream commit 41033f029e393a64e81966cbe34d66c6cf8a2e7e ]

the OUTMCAST stat is double incremented, getting bumped once in the mcast code
itself, and again in the common ip output path.  Remove the mcast bump, as its
not needed

Validated by the reporter, with good results

Signed-off-by: Neil Horman 
Reported-by: Claus Jensen 
CC: Claus Jensen 
CC: David Miller 
Signed-off-by: David S. Miller 
Signed-off-by: Jiri Slaby

ipv6: fix tunnel error handling

2015-11-30T09:34:46+00:00

commit ebac62fe3d24c0ce22dd83afa7b07d1a2aaef44d upstream.

Both tunnel6_protocol and tunnel46_protocol share the same error
handler, tunnel6_err(), which traverses through tunnel6_handlers list.
For ipip6 tunnels, we need to traverse tunnel46_handlers as we do e.g.
in tunnel46_rcv(). Current code can generate an ICMPv6 error message
with an IPv4 packet embedded in it.

Fixes: 73d605d1abbd ("[IPSEC]: changing API of xfrm6_tunnel_register")
Signed-off-by: Michal Kubecek 
Signed-off-by: David S. Miller 
Signed-off-by: Jiri Slaby