If a low prio writer gets preempted while holding the seqlock write
locked, a high prio reader spins forever on RT.
To prevent this let the reader grab the spinlock, so it blocks and
eventually boosts the writer. This way the writer can proceed and
endless spinning is prevented.
For seqcount writers we disable preemption over the update code
path. Thaanks to Al Viro for distangling some VFS code to make that
possible.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable-rt@vger.kernel.org
There are (probably rare) situations when a system crashed and the system
console becomes unresponsive but the network icmp layer still is alive.
Wouldn't it be wonderful, if we then could submit a sysreq command via ping?
This patch provides this facility. Please consult the updated documentation
Documentation/sysrq.txt for details.
Signed-off-by: Carsten Emde <C.Emde@osadl.org>
[ Upstream commit f60e5990d9 ]
We should not consult skb->sk for output decisions in xmit recursion
levels > 0 in the stack. Otherwise local socket settings could influence
the result of e.g. tunnel encapsulation process.
ipv6 does not conform with this in three places:
1) ip6_fragment: we do consult ipv6_npinfo for frag_size
2) sk_mc_loop in ipv6 uses skb->sk and checks if we should
loop the packet back to the local socket
3) ip6_skb_dst_mtu could query the settings from the user socket and
force a wrong MTU
Furthermore:
In sk_mc_loop we could potentially land in WARN_ON(1) if we use a
PF_PACKET socket ontop of an IPv6-backed vxlan device.
Reuse xmit_recursion as we are currently only interested in protecting
tunnel devices.
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit bdbbb8527b ]
In commit be9f4a44e7 ("ipv4: tcp: remove per net tcp_sock")
I tried to address contention on a socket lock, but the solution
I chose was horrible :
commit 3a7c384ffd ("ipv4: tcp: unicast_sock should not land outside
of TCP stack") addressed a selinux regression.
commit 0980e56e50 ("ipv4: tcp: set unicast_sock uc_ttl to -1")
took care of another regression.
commit b5ec8eeac4 ("ipv4: fix ip_send_skb()") fixed another regression.
commit 811230cd85 ("tcp: ipv4: initialize unicast_sock sk_pacing_rate")
was another shot in the dark.
Really, just use a proper socket per cpu, and remove the skb_orphan()
call, to re-enable flow control.
This solves a serious problem with FQ packet scheduler when used in
hostile environments, as we do not want to allocate a flow structure
for every RST packet sent in response to a spoofed packet.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit df4d92549f ]
Not caching dst_entries which cause redirects could be exploited by hosts
on the same subnet, causing a severe DoS attack. This effect aggravated
since commit f886497212 ("ipv4: fix dst race in sk_dst_get()").
Lookups causing redirects will be allocated with DST_NOCACHE set which
will force dst_release to free them via RCU. Unfortunately waiting for
RCU grace period just takes too long, we can end up with >1M dst_entries
waiting to be released and the system will run OOM. rcuos threads cannot
catch up under high softirq load.
Attaching the flag to emit a redirect later on to the specific skb allows
us to cache those dst_entries thus reducing the pressure on allocation
and deallocation.
This issue was discovered by Marcelo Leitner.
Cc: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Marcelo Leitner <mleitner@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9de7922bc7 upstream.
Commit 6f4c618ddb ("SCTP : Add paramters validity check for
ASCONF chunk") added basic verification of ASCONF chunks, however,
it is still possible to remotely crash a server by sending a
special crafted ASCONF chunk, even up to pre 2.6.12 kernels:
skb_over_panic: text:ffffffffa01ea1c3 len:31056 put:30768
head:ffff88011bd81800 data:ffff88011bd81800 tail:0x7950
end:0x440 dev:<NULL>
------------[ cut here ]------------
kernel BUG at net/core/skbuff.c:129!
[...]
Call Trace:
<IRQ>
[<ffffffff8144fb1c>] skb_put+0x5c/0x70
[<ffffffffa01ea1c3>] sctp_addto_chunk+0x63/0xd0 [sctp]
[<ffffffffa01eadaf>] sctp_process_asconf+0x1af/0x540 [sctp]
[<ffffffff8152d025>] ? _read_unlock_bh+0x15/0x20
[<ffffffffa01e0038>] sctp_sf_do_asconf+0x168/0x240 [sctp]
[<ffffffffa01e3751>] sctp_do_sm+0x71/0x1210 [sctp]
[<ffffffff8147645d>] ? fib_rules_lookup+0xad/0xf0
[<ffffffffa01e6b22>] ? sctp_cmp_addr_exact+0x32/0x40 [sctp]
[<ffffffffa01e8393>] sctp_assoc_bh_rcv+0xd3/0x180 [sctp]
[<ffffffffa01ee986>] sctp_inq_push+0x56/0x80 [sctp]
[<ffffffffa01fcc42>] sctp_rcv+0x982/0xa10 [sctp]
[<ffffffffa01d5123>] ? ipt_local_in_hook+0x23/0x28 [iptable_filter]
[<ffffffff8148bdc9>] ? nf_iterate+0x69/0xb0
[<ffffffff81496d10>] ? ip_local_deliver_finish+0x0/0x2d0
[<ffffffff8148bf86>] ? nf_hook_slow+0x76/0x120
[<ffffffff81496d10>] ? ip_local_deliver_finish+0x0/0x2d0
[<ffffffff81496ded>] ip_local_deliver_finish+0xdd/0x2d0
[<ffffffff81497078>] ip_local_deliver+0x98/0xa0
[<ffffffff8149653d>] ip_rcv_finish+0x12d/0x440
[<ffffffff81496ac5>] ip_rcv+0x275/0x350
[<ffffffff8145c88b>] __netif_receive_skb+0x4ab/0x750
[<ffffffff81460588>] netif_receive_skb+0x58/0x60
This can be triggered e.g., through a simple scripted nmap
connection scan injecting the chunk after the handshake, for
example, ...
-------------- INIT[ASCONF; ASCONF_ACK] ------------->
<----------- INIT-ACK[ASCONF; ASCONF_ACK] ------------
-------------------- COOKIE-ECHO -------------------->
<-------------------- COOKIE-ACK ---------------------
------------------ ASCONF; UNKNOWN ------------------>
... where ASCONF chunk of length 280 contains 2 parameters ...
1) Add IP address parameter (param length: 16)
2) Add/del IP address parameter (param length: 255)
... followed by an UNKNOWN chunk of e.g. 4 bytes. Here, the
Address Parameter in the ASCONF chunk is even missing, too.
This is just an example and similarly-crafted ASCONF chunks
could be used just as well.
The ASCONF chunk passes through sctp_verify_asconf() as all
parameters passed sanity checks, and after walking, we ended
up successfully at the chunk end boundary, and thus may invoke
sctp_process_asconf(). Parameter walking is done with
WORD_ROUND() to take padding into account.
In sctp_process_asconf()'s TLV processing, we may fail in
sctp_process_asconf_param() e.g., due to removal of the IP
address that is also the source address of the packet containing
the ASCONF chunk, and thus we need to add all TLVs after the
failure to our ASCONF response to remote via helper function
sctp_add_asconf_response(), which basically invokes a
sctp_addto_chunk() adding the error parameters to the given
skb.
When walking to the next parameter this time, we proceed
with ...
length = ntohs(asconf_param->param_hdr.length);
asconf_param = (void *)asconf_param + length;
... instead of the WORD_ROUND()'ed length, thus resulting here
in an off-by-one that leads to reading the follow-up garbage
parameter length of 12336, and thus throwing an skb_over_panic
for the reply when trying to sctp_addto_chunk() next time,
which implicitly calls the skb_put() with that length.
Fix it by using sctp_walk_params() [ which is also used in
INIT parameter processing ] macro in the verification *and*
in ASCONF processing: it will make sure we don't spill over,
that we walk parameters WORD_ROUND()'ed. Moreover, we're being
more defensive and guard against unknown parameter types and
missized addresses.
Joint work with Vlad Yasevich.
Fixes: b896b82be4ae ("[SCTP] ADDIP: Support for processing incoming ASCONF_ACK chunks.")
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Vlad Yasevich <vyasevich@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: Josh Boyer <jwboyer@fedoraproject.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit b69040d8e3 upstream.
When receiving a e.g. semi-good formed connection scan in the
form of ...
-------------- INIT[ASCONF; ASCONF_ACK] ------------->
<----------- INIT-ACK[ASCONF; ASCONF_ACK] ------------
-------------------- COOKIE-ECHO -------------------->
<-------------------- COOKIE-ACK ---------------------
---------------- ASCONF_a; ASCONF_b ----------------->
... where ASCONF_a equals ASCONF_b chunk (at least both serials
need to be equal), we panic an SCTP server!
The problem is that good-formed ASCONF chunks that we reply with
ASCONF_ACK chunks are cached per serial. Thus, when we receive a
same ASCONF chunk twice (e.g. through a lost ASCONF_ACK), we do
not need to process them again on the server side (that was the
idea, also proposed in the RFC). Instead, we know it was cached
and we just resend the cached chunk instead. So far, so good.
Where things get nasty is in SCTP's side effect interpreter, that
is, sctp_cmd_interpreter():
While incoming ASCONF_a (chunk = event_arg) is being marked
!end_of_packet and !singleton, and we have an association context,
we do not flush the outqueue the first time after processing the
ASCONF_ACK singleton chunk via SCTP_CMD_REPLY. Instead, we keep it
queued up, although we set local_cork to 1. Commit 2e3216cd54
changed the precedence, so that as long as we get bundled, incoming
chunks we try possible bundling on outgoing queue as well. Before
this commit, we would just flush the output queue.
Now, while ASCONF_a's ASCONF_ACK sits in the corked outq, we
continue to process the same ASCONF_b chunk from the packet. As
we have cached the previous ASCONF_ACK, we find it, grab it and
do another SCTP_CMD_REPLY command on it. So, effectively, we rip
the chunk->list pointers and requeue the same ASCONF_ACK chunk
another time. Since we process ASCONF_b, it's correctly marked
with end_of_packet and we enforce an uncork, and thus flush, thus
crashing the kernel.
Fix it by testing if the ASCONF_ACK is currently pending and if
that is the case, do not requeue it. When flushing the output
queue we may relink the chunk for preparing an outgoing packet,
but eventually unlink it when it's copied into the skb right
before transmission.
Joint work with Vlad Yasevich.
Fixes: 2e3216cd54 ("sctp: Follow security requirement of responding with 1 packet")
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: Josh Boyer <jwboyer@fedoraproject.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 5188cd44c5 ]
UFO is now disabled on all drivers that work with virtio net headers,
but userland may try to send UFO/IPv6 packets anyway. Instead of
sending with ID=0, we should select identifiers on their behalf (as we
used to).
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Fixes: 916e4cf46d ("ipv6: reuse ip6_frag_id from ip6_ufo_append_data")
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit bdf6fa52f0 ]
Currently association restarts do not take into consideration the
state of the socket. When a restart happens, the current assocation
simply transitions into established state. This creates a condition
where a remote system, through a the restart procedure, may create a
local association that is no way reachable by user. The conditions
to trigger this are as follows:
1) Remote does not acknoledge some data causing data to remain
outstanding.
2) Local application calls close() on the socket. Since data
is still outstanding, the association is placed in SHUTDOWN_PENDING
state. However, the socket is closed.
3) The remote tries to create a new association, triggering a restart
on the local system. The association moves from SHUTDOWN_PENDING
to ESTABLISHED. At this point, it is no longer reachable by
any socket on the local system.
This patch addresses the above situation by moving the newly ESTABLISHED
association into SHUTDOWN-SENT state and bundling a SHUTDOWN after
the COOKIE-ACK chunk. This way, the restarted associate immidiately
enters the shutdown procedure and forces the termination of the
unreachable association.
Reported-by: David Laight <David.Laight@aculab.com>
Signed-off-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit b8c203b2d2 ]
Currently we genarate a queueing route if we have matching policies
but can not resolve the states and the sysctl xfrm_larval_drop is
disabled. Here we assume that dst_output() is called to kill the
queued packets. Unfortunately this assumption is not true in all
cases, so it is possible that these packets leave the system unwanted.
We fix this by generating queueing routes only from the
route lookup functions, here we can guarantee a call to
dst_output() afterwards.
Fixes: a0073fe18e ("xfrm: Add a state resolution packet queue")
Reported-by: Konstantinos Kolelis <k.kolelis@sirrix.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit f92ee61982 ]
Currently we genarate a blackhole route route whenever we have
matching policies but can not resolve the states. Here we assume
that dst_output() is called to kill the balckholed packets.
Unfortunately this assumption is not true in all cases, so
it is possible that these packets leave the system unwanted.
We fix this by generating blackhole routes only from the
route lookup functions, here we can guarantee a call to
dst_output() afterwards.
Fixes: 2774c131b1 ("xfrm: Handle blackhole route creation via afinfo.")
Reported-by: Konstantinos Kolelis <k.kolelis@sirrix.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 4fab907195 ]
Make sure we use the correct address-family-specific function for
handling MTU reductions from within tcp_release_cb().
Previously AF_INET6 sockets were incorrectly always using the IPv6
code path when sometimes they were handling IPv4 traffic and thus had
an IPv4 dst.
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Diagnosed-by: Willem de Bruijn <willemb@google.com>
Fixes: 563d34d057 ("tcp: dont drop MTU reduction indications")
Reviewed-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a5fe8e7695 upstream.
alpha2 is defined as 2-chars array, but is used in multiple
places as string (e.g. with nla_put_string calls), which
might leak kernel data.
Solve it by simply adding an extra char for the NULL
terminator, making such operations safe.
Signed-off-by: Eliad Peller <eliadx.peller@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 95cb574598 ]
Ipv4 tunnels created with "local any remote $ip" didn't work properly since
7d442fab0 (ipv4: Cache dst in tunnels). 99% of packets sent via those tunnels
had src addr = 0.0.0.0. That was because only dst_entry was cached, although
fl4.saddr has to be cached too. Every time ip_tunnel_xmit used cached dst_entry
(tunnel_rtable_get returned non-NULL), fl4.saddr was initialized with
tnl_params->saddr (= 0 in our case), and wasn't changed until iptunnel_xmit().
This patch adds saddr to ip_tunnel->dst_cache, fixing this issue.
Reported-by: Sergey Popov <pinkbyte@gentoo.org>
Signed-off-by: Dmitry Popov <ixaphire@qrator.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 04ca6973f7 ]
In "Counting Packets Sent Between Arbitrary Internet Hosts", Jeffrey and
Jedidiah describe ways exploiting linux IP identifier generation to
infer whether two machines are exchanging packets.
With commit 73f156a6e8 ("inetpeer: get rid of ip_id_count"), we
changed IP id generation, but this does not really prevent this
side-channel technique.
This patch adds a random amount of perturbation so that IP identifiers
for a given destination [1] are no longer monotonically increasing after
an idle period.
Note that prandom_u32_max(1) returns 0, so if generator is used at most
once per jiffy, this patch inserts no hole in the ID suite and do not
increase collision probability.
This is jiffies based, so in the worst case (HZ=1000), the id can
rollover after ~65 seconds of idle time, which should be fine.
We also change the hash used in __ip_select_ident() to not only hash
on daddr, but also saddr and protocol, so that ICMP probes can not be
used to infer information for other protocols.
For IPv6, adds saddr into the hash as well, but not nexthdr.
If I ping the patched target, we can see ID are now hard to predict.
21:57:11.008086 IP (...)
A > target: ICMP echo request, seq 1, length 64
21:57:11.010752 IP (... id 2081 ...)
target > A: ICMP echo reply, seq 1, length 64
21:57:12.013133 IP (...)
A > target: ICMP echo request, seq 2, length 64
21:57:12.015737 IP (... id 3039 ...)
target > A: ICMP echo reply, seq 2, length 64
21:57:13.016580 IP (...)
A > target: ICMP echo request, seq 3, length 64
21:57:13.019251 IP (... id 3437 ...)
target > A: ICMP echo reply, seq 3, length 64
[1] TCP sessions uses a per flow ID generator not changed by this patch.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Jeffrey Knockel <jeffk@cs.unm.edu>
Reported-by: Jedidiah R. Crandall <crandall@cs.unm.edu>
Cc: Willy Tarreau <w@1wt.eu>
Cc: Hannes Frederic Sowa <hannes@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 73f156a6e8 ]
Ideally, we would need to generate IP ID using a per destination IP
generator.
linux kernels used inet_peer cache for this purpose, but this had a huge
cost on servers disabling MTU discovery.
1) each inet_peer struct consumes 192 bytes
2) inetpeer cache uses a binary tree of inet_peer structs,
with a nominal size of ~66000 elements under load.
3) lookups in this tree are hitting a lot of cache lines, as tree depth
is about 20.
4) If server deals with many tcp flows, we have a high probability of
not finding the inet_peer, allocating a fresh one, inserting it in
the tree with same initial ip_id_count, (cf secure_ip_id())
5) We garbage collect inet_peer aggressively.
IP ID generation do not have to be 'perfect'
Goal is trying to avoid duplicates in a short period of time,
so that reassembly units have a chance to complete reassembly of
fragments belonging to one message before receiving other fragments
with a recycled ID.
We simply use an array of generators, and a Jenkin hash using the dst IP
as a key.
ipv6_select_ident() is put back into net/ipv6/ip6_output.c where it
belongs (it is only used from this file)
secure_ip_id() and secure_ipv6_id() no longer are needed.
Rename ip_select_ident_more() to ip_select_ident_segs() to avoid
unnecessary decrement/increment of the number of segments.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 5925a0555b ]
sk_dst_cache has __rcu annotation, so we need a cast to avoid
following sparse error :
include/net/sock.h:1774:19: warning: incorrect type in initializer (different address spaces)
include/net/sock.h:1774:19: expected struct dst_entry [noderef] <asn:4>*__ret
include/net/sock.h:1774:19: got struct dst_entry *dst
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Fixes: 7f50236153 ("ipv4: irq safe sk_dst_[re]set() and ipv4_sk_update_pmtu() fix")
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 7f50236153 ]
We have two different ways to handle changes to sk->sk_dst
First way (used by TCP) assumes socket lock is owned by caller, and use
no extra lock : __sk_dst_set() & __sk_dst_reset()
Another way (used by UDP) uses sk_dst_lock because socket lock is not
always taken. Note that sk_dst_lock is not softirq safe.
These ways are not inter changeable for a given socket type.
ipv4_sk_update_pmtu(), added in linux-3.8, added a race, as it used
the socket lock as synchronization, but users might be UDP sockets.
Instead of converting sk_dst_lock to a softirq safe version, use xchg()
as we did for sk_rx_dst in commit e47eb5dfb2 ("udp: ipv4: do not use
sk_dst_lock from softirq context")
In a follow up patch, we probably can remove sk_dst_lock, as it is
only used in IPv6.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Fixes: 9cb3a50c5f ("ipv4: Invalidate the socket cached route on pmtu events if possible")
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit f886497212 ]
When IP route cache had been removed in linux-3.6, we broke assumption
that dst entries were all freed after rcu grace period. DST_NOCACHE
dst were supposed to be freed from dst_release(). But it appears
we want to keep such dst around, either in UDP sockets or tunnels.
In sk_dst_get() we need to make sure dst refcount is not 0
before incrementing it, or else we might end up freeing a dst
twice.
DST_NOCACHE set on a dst does not mean this dst can not be attached
to a socket or a tunnel.
Then, before actual freeing, we need to observe a rcu grace period
to make sure all other cpus can catch the fact the dst is no longer
usable.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Dormando <dormando@rydia.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 39c36094d7 ]
I noticed we were sending wrong IPv4 ID in TCP flows when MTU discovery
is disabled.
Note how GSO/TSO packets do not have monotonically incrementing ID.
06:37:41.575531 IP (id 14227, proto: TCP (6), length: 4396)
06:37:41.575534 IP (id 14272, proto: TCP (6), length: 65212)
06:37:41.575544 IP (id 14312, proto: TCP (6), length: 57972)
06:37:41.575678 IP (id 14317, proto: TCP (6), length: 7292)
06:37:41.575683 IP (id 14361, proto: TCP (6), length: 63764)
It appears I introduced this bug in linux-3.1.
inet_getid() must return the old value of peer->ip_id_count,
not the new one.
Lets revert this part, and remove the prevention of
a null identification field in IPv6 Fragment Extension Header,
which is dubious and not even done properly.
Fixes: 87c48fa3b4 ("ipv6: make fragment identifications less predictable")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit a3b299da86 ]
sk_net_capable - The common case, operations that are safe in a network namespace.
sk_capable - Operations that are not known to be safe in a network namespace
sk_ns_capable - The general case for special cases.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 792e6aa7a1 upstream.
Add locked-version for cfg80211_sched_scan_stopped.
This is used for some users that might want to
call it when rtnl is already locked.
Fixes: d43c6b6 ("mac80211: reschedule sched scan after HW restart")
Signed-off-by: Eliad Peller <eliadx.peller@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 2c4a336e0a ]
Right now the core vsock module is the owner of the proto family. This
means there's nothing preventing the transport module from unloading if
there are open sockets, which results in a panic. Fix that by allowing
the transport to be the owner, which will refcount it properly.
Includes version bump to 1.0.1.0-k
Passes checkpatch this time, I swear...
Acked-by: Dmitry Torokhov <dtor@vmware.com>
Signed-off-by: Andy King <acking@vmware.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit b14878ccb7 ]
Currently, it is possible to create an SCTP socket, then switch
auth_enable via sysctl setting to 1 and crash the system on connect:
Oops[#1]:
CPU: 0 PID: 0 Comm: swapper Not tainted 3.14.1-mipsgit-20140415 #1
task: ffffffff8056ce80 ti: ffffffff8055c000 task.ti: ffffffff8055c000
[...]
Call Trace:
[<ffffffff8043c4e8>] sctp_auth_asoc_set_default_hmac+0x68/0x80
[<ffffffff8042b300>] sctp_process_init+0x5e0/0x8a4
[<ffffffff8042188c>] sctp_sf_do_5_1B_init+0x234/0x34c
[<ffffffff804228c8>] sctp_do_sm+0xb4/0x1e8
[<ffffffff80425a08>] sctp_endpoint_bh_rcv+0x1c4/0x214
[<ffffffff8043af68>] sctp_rcv+0x588/0x630
[<ffffffff8043e8e8>] sctp6_rcv+0x10/0x24
[<ffffffff803acb50>] ip6_input+0x2c0/0x440
[<ffffffff8030fc00>] __netif_receive_skb_core+0x4a8/0x564
[<ffffffff80310650>] process_backlog+0xb4/0x18c
[<ffffffff80313cbc>] net_rx_action+0x12c/0x210
[<ffffffff80034254>] __do_softirq+0x17c/0x2ac
[<ffffffff800345e0>] irq_exit+0x54/0xb0
[<ffffffff800075a4>] ret_from_irq+0x0/0x4
[<ffffffff800090ec>] rm7k_wait_irqoff+0x24/0x48
[<ffffffff8005e388>] cpu_startup_entry+0xc0/0x148
[<ffffffff805a88b0>] start_kernel+0x37c/0x398
Code: dd0900b8 000330f8 0126302d <dcc60000> 50c0fff1 0047182a a48306a0
03e00008 00000000
---[ end trace b530b0551467f2fd ]---
Kernel panic - not syncing: Fatal exception in interrupt
What happens while auth_enable=0 in that case is, that
ep->auth_hmacs is initialized to NULL in sctp_auth_init_hmacs()
when endpoint is being created.
After that point, if an admin switches over to auth_enable=1,
the machine can crash due to NULL pointer dereference during
reception of an INIT chunk. When we enter sctp_process_init()
via sctp_sf_do_5_1B_init() in order to respond to an INIT chunk,
the INIT verification succeeds and while we walk and process
all INIT params via sctp_process_param() we find that
net->sctp.auth_enable is set, therefore do not fall through,
but invoke sctp_auth_asoc_set_default_hmac() instead, and thus,
dereference what we have set to NULL during endpoint
initialization phase.
The fix is to make auth_enable immutable by caching its value
during endpoint initialization, so that its original value is
being carried along until destruction. The bug seems to originate
from the very first days.
Fix in joint work with Daniel Borkmann.
Reported-by: Joshua Kinard <kumba@gentoo.org>
Signed-off-by: Vlad Yasevich <vyasevic@redhat.com>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Tested-by: Joshua Kinard <kumba@gentoo.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 30f78d8ebf ]
Francois reported that setting big mtu on loopback device could prevent
tcp sessions making progress.
We do not support (yet ?) IPv6 Jumbograms and cook corrupted packets.
We must limit the IPv6 MTU to (65535 + 40) bytes in theory.
Tested:
ifconfig lo mtu 70000
netperf -H ::1
Before patch : Throughput : 0.05 Mbits
After patch : Throughput : 35484 Mbits
Reported-by: Francois WELLENREITER <f.wellenreiter@gmail.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 223b02d923 upstream.
"len" contains sizeof(nf_ct_ext) and size of extensions. In a worst
case it can contain all extensions. Bellow you can find sizes for all
types of extensions. Their sum is definitely bigger than 256.
nf_ct_ext_types[0]->len = 24
nf_ct_ext_types[1]->len = 32
nf_ct_ext_types[2]->len = 24
nf_ct_ext_types[3]->len = 32
nf_ct_ext_types[4]->len = 152
nf_ct_ext_types[5]->len = 2
nf_ct_ext_types[6]->len = 16
nf_ct_ext_types[7]->len = 8
I have seen "len" up to 280 and my host has crashes w/o this patch.
The right way to fix this problem is reducing the size of the ecache
extension (4) and Florian is going to do this, but these changes will
be quite large to be appropriate for a stable tree.
Fixes: 5b423f6a40 (netfilter: nf_conntrack: fix racy timer handling with reliable)
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Patrick McHardy <kaber@trash.net>
Cc: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit b855d416dc upstream.
nft_cmp_fast is used for equality comparisions of size <= 4. For
comparisions of size < 4 byte a mask is calculated that is applied to
both the data from userspace (during initialization) and the register
value (during runtime). Both values are stored using (in effect) memcpy
to a memory area that is then interpreted as u32 by nft_cmp_fast.
This works fine on little endian since smaller types have the same base
address, however on big endian this is not true and the smaller types
are interpreted as a big number with trailing zero bytes.
The mask therefore must not include the lower bytes, but the higher bytes
on big endian. Add a helper function that does a cpu_to_le32 to switch
the bytes on big endian. Since we're dealing with a mask of just consequitive
bits, this works out fine.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
addrconf_join_solict and addrconf_join_anycast may cause actions which
need rtnl locked, especially on first address creation.
A new DAD state is introduced which defers processing of the initial
DAD processing into a workqueue.
To get rtnl lock we need to push the code paths which depend on those
calls up to workqueues, specifically addrconf_verify and the DAD
processing.
(v2)
addrconf_dad_failure needs to be queued up to the workqueue, too. This
patch introduces a new DAD state and stop the DAD processing in the
workqueue (this is because of the possible ipv6_del_addr processing
which removes the solicited multicast address from the device).
addrconf_verify_lock is removed, too. After the transition it is not
needed any more.
As we are not processing in bottom half anymore we need to be a bit more
careful about disabling bottom half out when we lock spin_locks which are also
used in bh.
Relevant backtrace:
[ 541.030090] RTNL: assertion failed at net/core/dev.c (4496)
[ 541.031143] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G O 3.10.33-1-amd64-vyatta #1
[ 541.031145] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007
[ 541.031146] ffffffff8148a9f0 000000000000002f ffffffff813c98c1 ffff88007c4451f8
[ 541.031148] 0000000000000000 0000000000000000 ffffffff813d3540 ffff88007fc03d18
[ 541.031150] 0000880000000006 ffff88007c445000 ffffffffa0194160 0000000000000000
[ 541.031152] Call Trace:
[ 541.031153] <IRQ> [<ffffffff8148a9f0>] ? dump_stack+0xd/0x17
[ 541.031180] [<ffffffff813c98c1>] ? __dev_set_promiscuity+0x101/0x180
[ 541.031183] [<ffffffff813d3540>] ? __hw_addr_create_ex+0x60/0xc0
[ 541.031185] [<ffffffff813cfe1a>] ? __dev_set_rx_mode+0xaa/0xc0
[ 541.031189] [<ffffffff813d3a81>] ? __dev_mc_add+0x61/0x90
[ 541.031198] [<ffffffffa01dcf9c>] ? igmp6_group_added+0xfc/0x1a0 [ipv6]
[ 541.031208] [<ffffffff8111237b>] ? kmem_cache_alloc+0xcb/0xd0
[ 541.031212] [<ffffffffa01ddcd7>] ? ipv6_dev_mc_inc+0x267/0x300 [ipv6]
[ 541.031216] [<ffffffffa01c2fae>] ? addrconf_join_solict+0x2e/0x40 [ipv6]
[ 541.031219] [<ffffffffa01ba2e9>] ? ipv6_dev_ac_inc+0x159/0x1f0 [ipv6]
[ 541.031223] [<ffffffffa01c0772>] ? addrconf_join_anycast+0x92/0xa0 [ipv6]
[ 541.031226] [<ffffffffa01c311e>] ? __ipv6_ifa_notify+0x11e/0x1e0 [ipv6]
[ 541.031229] [<ffffffffa01c3213>] ? ipv6_ifa_notify+0x33/0x50 [ipv6]
[ 541.031233] [<ffffffffa01c36c8>] ? addrconf_dad_completed+0x28/0x100 [ipv6]
[ 541.031241] [<ffffffff81075c1d>] ? task_cputime+0x2d/0x50
[ 541.031244] [<ffffffffa01c38d6>] ? addrconf_dad_timer+0x136/0x150 [ipv6]
[ 541.031247] [<ffffffffa01c37a0>] ? addrconf_dad_completed+0x100/0x100 [ipv6]
[ 541.031255] [<ffffffff8105313a>] ? call_timer_fn.isra.22+0x2a/0x90
[ 541.031258] [<ffffffffa01c37a0>] ? addrconf_dad_completed+0x100/0x100 [ipv6]
Hunks and backtrace stolen from a patch by Stephen Hemminger.
Reported-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
While it is true that getnstimeofday() uses about 40 cycles if TSC
is available, it can use 1600 cycles if hpet is the clocksource.
Switch to get_jiffies_64(), as this is more than enough, and
go back to 60 seconds periods.
Fixes: 8c27bd75f0 ("tcp: syncookies: reduce cookie lifetime to 128 seconds")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Florian Westphal <fw@strlen.de>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
The original documentation was very unclear.
The code fix is presumably related to the formerly unclear
documentation: SOCK_TIMESTAMPING_RX_SOFTWARE has no effect on
__sock_recv_timestamp's behavior, so calling __sock_recv_ts_and_drops
from sock_recv_ts_and_drops if only SOCK_TIMESTAMPING_RX_SOFTWARE is
set is pointless. This should have no user-observable effect.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Steffen Klassert says:
====================
1) Build fix for ip_vti when NET_IP_TUNNEL is not set.
We need this set to have ip_tunnel_get_stats64()
available.
2) Fix a NULL pointer dereference on sub policy usage.
We try to access a xfrm_state from the wrong array.
3) Take xfrm_state_lock in xfrm_migrate_state_find(),
we need it to traverse through the state lists.
4) Clone states properly on migration, otherwise we crash
when we migrate a state with aead algorithm attached.
5) Fix unlink race when between thread context and timer
when policies are deleted.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch fixes two bugs in fastopen :
1) The tcp_sendmsg(..., @size) argument was ignored.
Code was relying on user not fooling the kernel with iovec mismatches
2) When MTU is about 64KB, tcp_send_syn_data() attempts order-5
allocations, which are likely to fail when memory gets fragmented.
Fixes: 783237e8da ("net-tcp: Fast Open client - sending SYN-data")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Tested-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Bug introduced by commit 7d442fab0a ("ipv4: Cache dst in tunnels").
Because sit code does not call ip_tunnel_init(), the dst_cache was not
initialized.
CC: Tom Herbert <therbert@google.com>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
We loose a lot of information of the original state if we
clone it with xfrm_state_clone(). In particular, there is
no crypto algorithm attached if the original state uses
an aead algorithm. This patch add the missing information
to the clone state.
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Implementation of (a)rwnd calculation might lead to severe performance issues
and associations completely stalling. These problems are described and solution
is proposed which improves lksctp's robustness in congestion state.
1) Sudden drop of a_rwnd and incomplete window recovery afterwards
Data accounted in sctp_assoc_rwnd_decrease takes only payload size (sctp data),
but size of sk_buff, which is blamed against receiver buffer, is not accounted
in rwnd. Theoretically, this should not be the problem as actual size of buffer
is double the amount requested on the socket (SO_RECVBUF). Problem here is
that this will have bad scaling for data which is less then sizeof sk_buff.
E.g. in 4G (LTE) networks, link interfacing radio side will have a large portion
of traffic of this size (less then 100B).
An example of sudden drop and incomplete window recovery is given below. Node B
exhibits problematic behavior. Node A initiates association and B is configured
to advertise rwnd of 10000. A sends messages of size 43B (size of typical sctp
message in 4G (LTE) network). On B data is left in buffer by not reading socket
in userspace.
Lets examine when we will hit pressure state and declare rwnd to be 0 for
scenario with above stated parameters (rwnd == 10000, chunk size == 43, each
chunk is sent in separate sctp packet)
Logic is implemented in sctp_assoc_rwnd_decrease:
socket_buffer (see below) is maximum size which can be held in socket buffer
(sk_rcvbuf). current_alloced is amount of data currently allocated (rx_count)
A simple expression is given for which it will be examined after how many
packets for above stated parameters we enter pressure state:
We start by condition which has to be met in order to enter pressure state:
socket_buffer < currently_alloced;
currently_alloced is represented as size of sctp packets received so far and not
yet delivered to userspace. x is the number of chunks/packets (since there is no
bundling, and each chunk is delivered in separate packet, we can observe each
chunk also as sctp packet, and what is important here, having its own sk_buff):
socket_buffer < x*each_sctp_packet;
each_sctp_packet is sctp chunk size + sizeof(struct sk_buff). socket_buffer is
twice the amount of initially requested size of socket buffer, which is in case
of sctp, twice the a_rwnd requested:
2*rwnd < x*(payload+sizeof(struc sk_buff));
sizeof(struct sk_buff) is 190 (3.13.0-rc4+). Above is stated that rwnd is 10000
and each payload size is 43
20000 < x(43+190);
x > 20000/233;
x ~> 84;
After ~84 messages, pressure state is entered and 0 rwnd is advertised while
received 84*43B ~= 3612B sctp data. This is why external observer notices sudden
drop from 6474 to 0, as it will be now shown in example:
IP A.34340 > B.12345: sctp (1) [INIT] [init tag: 1875509148] [rwnd: 81920] [OS: 10] [MIS: 65535] [init TSN: 1096057017]
IP B.12345 > A.34340: sctp (1) [INIT ACK] [init tag: 3198966556] [rwnd: 10000] [OS: 10] [MIS: 10] [init TSN: 902132839]
IP A.34340 > B.12345: sctp (1) [COOKIE ECHO]
IP B.12345 > A.34340: sctp (1) [COOKIE ACK]
IP A.34340 > B.12345: sctp (1) [DATA] (B)(E) [TSN: 1096057017] [SID: 0] [SSEQ 0] [PPID 0x18]
IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057017] [a_rwnd 9957] [#gap acks 0] [#dup tsns 0]
IP A.34340 > B.12345: sctp (1) [DATA] (B)(E) [TSN: 1096057018] [SID: 0] [SSEQ 1] [PPID 0x18]
IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057018] [a_rwnd 9957] [#gap acks 0] [#dup tsns 0]
IP A.34340 > B.12345: sctp (1) [DATA] (B)(E) [TSN: 1096057019] [SID: 0] [SSEQ 2] [PPID 0x18]
IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057019] [a_rwnd 9914] [#gap acks 0] [#dup tsns 0]
<...>
IP A.34340 > B.12345: sctp (1) [DATA] (B)(E) [TSN: 1096057098] [SID: 0] [SSEQ 81] [PPID 0x18]
IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057098] [a_rwnd 6517] [#gap acks 0] [#dup tsns 0]
IP A.34340 > B.12345: sctp (1) [DATA] (B)(E) [TSN: 1096057099] [SID: 0] [SSEQ 82] [PPID 0x18]
IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057099] [a_rwnd 6474] [#gap acks 0] [#dup tsns 0]
IP A.34340 > B.12345: sctp (1) [DATA] (B)(E) [TSN: 1096057100] [SID: 0] [SSEQ 83] [PPID 0x18]
--> Sudden drop
IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057100] [a_rwnd 0] [#gap acks 0] [#dup tsns 0]
At this point, rwnd_press stores current rwnd value so it can be later restored
in sctp_assoc_rwnd_increase. This however doesn't happen as condition to start
slowly increasing rwnd until rwnd_press is returned to rwnd is never met. This
condition is not met since rwnd, after it hit 0, must first reach rwnd_press by
adding amount which is read from userspace. Let us observe values in above
example. Initial a_rwnd is 10000, pressure was hit when rwnd was ~6500 and the
amount of actual sctp data currently waiting to be delivered to userspace
is ~3500. When userspace starts to read, sctp_assoc_rwnd_increase will be blamed
only for sctp data, which is ~3500. Condition is never met, and when userspace
reads all data, rwnd stays on 3569.
IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057100] [a_rwnd 1505] [#gap acks 0] [#dup tsns 0]
IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057100] [a_rwnd 3010] [#gap acks 0] [#dup tsns 0]
IP A.34340 > B.12345: sctp (1) [DATA] (B)(E) [TSN: 1096057101] [SID: 0] [SSEQ 84] [PPID 0x18]
IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057101] [a_rwnd 3569] [#gap acks 0] [#dup tsns 0]
--> At this point userspace read everything, rwnd recovered only to 3569
IP A.34340 > B.12345: sctp (1) [DATA] (B)(E) [TSN: 1096057102] [SID: 0] [SSEQ 85] [PPID 0x18]
IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057102] [a_rwnd 3569] [#gap acks 0] [#dup tsns 0]
Reproduction is straight forward, it is enough for sender to send packets of
size less then sizeof(struct sk_buff) and receiver keeping them in its buffers.
2) Minute size window for associations sharing the same socket buffer
In case multiple associations share the same socket, and same socket buffer
(sctp.rcvbuf_policy == 0), different scenarios exist in which congestion on one
of the associations can permanently drop rwnd of other association(s).
Situation will be typically observed as one association suddenly having rwnd
dropped to size of last packet received and never recovering beyond that point.
Different scenarios will lead to it, but all have in common that one of the
associations (let it be association from 1)) nearly depleted socket buffer, and
the other association blames socket buffer just for the amount enough to start
the pressure. This association will enter pressure state, set rwnd_press and
announce 0 rwnd.
When data is read by userspace, similar situation as in 1) will occur, rwnd will
increase just for the size read by userspace but rwnd_press will be high enough
so that association doesn't have enough credit to reach rwnd_press and restore
to previous state. This case is special case of 1), being worse as there is, in
the worst case, only one packet in buffer for which size rwnd will be increased.
Consequence is association which has very low maximum rwnd ('minute size', in
our case down to 43B - size of packet which caused pressure) and as such
unusable.
Scenario happened in the field and labs frequently after congestion state (link
breaks, different probabilities of packet drop, packet reordering) and with
scenario 1) preceding. Here is given a deterministic scenario for reproduction:
>From node A establish two associations on the same socket, with rcvbuf_policy
being set to share one common buffer (sctp.rcvbuf_policy == 0). On association 1
repeat scenario from 1), that is, bring it down to 0 and restore up. Observe
scenario 1). Use small payload size (here we use 43). Once rwnd is 'recovered',
bring it down close to 0, as in just one more packet would close it. This has as
a consequence that association number 2 is able to receive (at least) one more
packet which will bring it in pressure state. E.g. if association 2 had rwnd of
10000, packet received was 43, and we enter at this point into pressure,
rwnd_press will have 9957. Once payload is delivered to userspace, rwnd will
increase for 43, but conditions to restore rwnd to original state, just as in
1), will never be satisfied.
--> Association 1, between A.y and B.12345
IP A.55915 > B.12345: sctp (1) [INIT] [init tag: 836880897] [rwnd: 10000] [OS: 10] [MIS: 65535] [init TSN: 4032536569]
IP B.12345 > A.55915: sctp (1) [INIT ACK] [init tag: 2873310749] [rwnd: 81920] [OS: 10] [MIS: 10] [init TSN: 3799315613]
IP A.55915 > B.12345: sctp (1) [COOKIE ECHO]
IP B.12345 > A.55915: sctp (1) [COOKIE ACK]
--> Association 2, between A.z and B.12346
IP A.55915 > B.12346: sctp (1) [INIT] [init tag: 534798321] [rwnd: 10000] [OS: 10] [MIS: 65535] [init TSN: 2099285173]
IP B.12346 > A.55915: sctp (1) [INIT ACK] [init tag: 516668823] [rwnd: 81920] [OS: 10] [MIS: 10] [init TSN: 3676403240]
IP A.55915 > B.12346: sctp (1) [COOKIE ECHO]
IP B.12346 > A.55915: sctp (1) [COOKIE ACK]
--> Deplete socket buffer by sending messages of size 43B over association 1
IP B.12345 > A.55915: sctp (1) [DATA] (B)(E) [TSN: 3799315613] [SID: 0] [SSEQ 0] [PPID 0x18]
IP A.55915 > B.12345: sctp (1) [SACK] [cum ack 3799315613] [a_rwnd 9957] [#gap acks 0] [#dup tsns 0]
<...>
IP A.55915 > B.12345: sctp (1) [SACK] [cum ack 3799315696] [a_rwnd 6388] [#gap acks 0] [#dup tsns 0]
IP B.12345 > A.55915: sctp (1) [DATA] (B)(E) [TSN: 3799315697] [SID: 0] [SSEQ 84] [PPID 0x18]
IP A.55915 > B.12345: sctp (1) [SACK] [cum ack 3799315697] [a_rwnd 6345] [#gap acks 0] [#dup tsns 0]
--> Sudden drop on 1
IP B.12345 > A.55915: sctp (1) [DATA] (B)(E) [TSN: 3799315698] [SID: 0] [SSEQ 85] [PPID 0x18]
IP A.55915 > B.12345: sctp (1) [SACK] [cum ack 3799315698] [a_rwnd 0] [#gap acks 0] [#dup tsns 0]
--> Here userspace read, rwnd 'recovered' to 3698, now deplete again using
association 1 so there is place in buffer for only one more packet
IP B.12345 > A.55915: sctp (1) [DATA] (B)(E) [TSN: 3799315799] [SID: 0] [SSEQ 186] [PPID 0x18]
IP A.55915 > B.12345: sctp (1) [SACK] [cum ack 3799315799] [a_rwnd 86] [#gap acks 0] [#dup tsns 0]
IP B.12345 > A.55915: sctp (1) [DATA] (B)(E) [TSN: 3799315800] [SID: 0] [SSEQ 187] [PPID 0x18]
IP A.55915 > B.12345: sctp (1) [SACK] [cum ack 3799315800] [a_rwnd 43] [#gap acks 0] [#dup tsns 0]
--> Socket buffer is almost depleted, but there is space for one more packet,
send them over association 2, size 43B
IP B.12346 > A.55915: sctp (1) [DATA] (B)(E) [TSN: 3676403240] [SID: 0] [SSEQ 0] [PPID 0x18]
IP A.55915 > B.12346: sctp (1) [SACK] [cum ack 3676403240] [a_rwnd 0] [#gap acks 0] [#dup tsns 0]
--> Immediate drop
IP A.60995 > B.12346: sctp (1) [SACK] [cum ack 387491510] [a_rwnd 0] [#gap acks 0] [#dup tsns 0]
--> Read everything from the socket, both association recover up to maximum rwnd
they are capable of reaching, note that association 1 recovered up to 3698,
and association 2 recovered only to 43
IP A.55915 > B.12345: sctp (1) [SACK] [cum ack 3799315800] [a_rwnd 1548] [#gap acks 0] [#dup tsns 0]
IP A.55915 > B.12345: sctp (1) [SACK] [cum ack 3799315800] [a_rwnd 3053] [#gap acks 0] [#dup tsns 0]
IP B.12345 > A.55915: sctp (1) [DATA] (B)(E) [TSN: 3799315801] [SID: 0] [SSEQ 188] [PPID 0x18]
IP A.55915 > B.12345: sctp (1) [SACK] [cum ack 3799315801] [a_rwnd 3698] [#gap acks 0] [#dup tsns 0]
IP B.12346 > A.55915: sctp (1) [DATA] (B)(E) [TSN: 3676403241] [SID: 0] [SSEQ 1] [PPID 0x18]
IP A.55915 > B.12346: sctp (1) [SACK] [cum ack 3676403241] [a_rwnd 43] [#gap acks 0] [#dup tsns 0]
A careful reader might wonder why it is necessary to reproduce 1) prior
reproduction of 2). It is simply easier to observe when to send packet over
association 2 which will push association into the pressure state.
Proposed solution:
Both problems share the same root cause, and that is improper scaling of socket
buffer with rwnd. Solution in which sizeof(sk_buff) is taken into concern while
calculating rwnd is not possible due to fact that there is no linear
relationship between amount of data blamed in increase/decrease with IP packet
in which payload arrived. Even in case such solution would be followed,
complexity of the code would increase. Due to nature of current rwnd handling,
slow increase (in sctp_assoc_rwnd_increase) of rwnd after pressure state is
entered is rationale, but it gives false representation to the sender of current
buffer space. Furthermore, it implements additional congestion control mechanism
which is defined on implementation, and not on standard basis.
Proposed solution simplifies whole algorithm having on mind definition from rfc:
o Receiver Window (rwnd): This gives the sender an indication of the space
available in the receiver's inbound buffer.
Core of the proposed solution is given with these lines:
sctp_assoc_rwnd_update:
if ((asoc->base.sk->sk_rcvbuf - rx_count) > 0)
asoc->rwnd = (asoc->base.sk->sk_rcvbuf - rx_count) >> 1;
else
asoc->rwnd = 0;
We advertise to sender (half of) actual space we have. Half is in the braces
depending whether you would like to observe size of socket buffer as SO_RECVBUF
or twice the amount, i.e. size is the one visible from userspace, that is,
from kernelspace.
In this way sender is given with good approximation of our buffer space,
regardless of the buffer policy - we always advertise what we have. Proposed
solution fixes described problems and removes necessity for rwnd restoration
algorithm. Finally, as proposed solution is simplification, some lines of code,
along with some bytes in struct sctp_association are saved.
Version 2 of the patch addressed comments from Vlad. Name of the function is set
to be more descriptive, and two parts of code are changed, in one removing the
superfluous call to sctp_assoc_rwnd_update since call would not result in update
of rwnd, and the other being reordering of the code in a way that call to
sctp_assoc_rwnd_update updates rwnd. Version 3 corrected change introduced in v2
in a way that existing function is not reordered/copied in line, but it is
correctly called. Thanks Vlad for suggesting.
Signed-off-by: Matija Glavinic Pecotic <matija.glavinic-pecotic.ext@nsn.com>
Reviewed-by: Alexander Sverdlin <alexander.sverdlin@nsn.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Move prototype declaration of function to header file
include/net/net_namespace.h from net/ipx/af_ipx.c because they are used
by more than one file.
This eliminates the following warning in net/ipx/sysctl_net_ipx.c:
net/ipx/sysctl_net_ipx.c:33:6: warning: no previous prototype for ‘ipx_register_sysctl’ [-Wmissing-prototypes]
net/ipx/sysctl_net_ipx.c:38:6: warning: no previous prototype for ‘ipx_unregister_sysctl’ [-Wmissing-prototypes]
Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Move prototype declarations of function to header file
include/net/datalink.h from net/ipx/af_ipx.c because they are used by
more than one file.
This eliminates the following warning in net/ipx/pe2.c:
net/ipx/pe2.c:20:24: warning: no previous prototype for ‘make_EII_client’ [-Wmissing-prototypes]
net/ipx/pe2.c:32:6: warning: no previous prototype for ‘destroy_EII_client’ [-Wmissing-prototypes]
Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Move prototype declaration of functions to header file include/net/ipx.h
from net/ipx/af_ipx.c because they are used by more than one file.
This eliminates the following warning in
net/ipx/ipx_route.c:33:19: warning: no previous prototype for ‘ipxrtr_lookup’ [-Wmissing-prototypes]
net/ipx/ipx_route.c:52:5: warning: no previous prototype for ‘ipxrtr_add_route’ [-Wmissing-prototypes]
net/ipx/ipx_route.c:94:6: warning: no previous prototype for ‘ipxrtr_del_routes’ [-Wmissing-prototypes]
net/ipx/ipx_route.c:149:5: warning: no previous prototype for ‘ipxrtr_route_skb’ [-Wmissing-prototypes]
net/ipx/ipx_route.c:171:5: warning: no previous prototype for ‘ipxrtr_route_packet’ [-Wmissing-prototypes]
net/ipx/ipx_route.c:261:5: warning: no previous prototype for ‘ipxrtr_ioctl’ [-Wmissing-prototypes]
Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Move prototype definition of function to header file include/net/ipx.h
from net/ipx/ipx_route.c because they are used by more than one file.
This eliminates the following warning from net/ipx/af_ipx.c:
net/ipx/af_ipx.c:193:23: warning: no previous prototype for ‘ipxitf_find_using_net’ [-Wmissing-prototypes]
net/ipx/af_ipx.c:577:5: warning: no previous prototype for ‘ipxitf_send’ [-Wmissing-prototypes]
net/ipx/af_ipx.c:1219:8: warning: no previous prototype for ‘ipx_cksum’ [-Wmissing-prototypes]
Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Move prototype declaration of functions to header file include/net/dn.h
from net/decnet/af_decnet.c because they are used by more than one file.
This eliminates the following warning in net/decnet/af_decnet.c:
net/decnet/sysctl_net_decnet.c:354:6: warning: no previous prototype for ‘dn_register_sysctl’ [-Wmissing-prototypes]
net/decnet/sysctl_net_decnet.c:359:6: warning: no previous prototype for ‘dn_unregister_sysctl’ [-Wmissing-prototypes]
Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Move prototype declaration of functions to header file include/net/dn_route.h
from net/decnet/af_decnet.c because it is used by more than one file.
This eliminates the following warning in net/decnet/dn_route.c:
net/decnet/dn_route.c:629:5: warning: no previous prototype for ‘dn_route_rcv’ [-Wmissing-prototypes]
Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pablo Neira Ayuso says:
====================
Netfilter/nftables/IPVS fixes for net
The following patchset contains Netfilter/IPVS fixes, mostly nftables
fixes, most relevantly they are:
* Fix a crash in the h323 conntrack NAT helper due to expectation list
corruption, from Alexey Dobriyan.
* A couple of RCU race fixes for conntrack, one manifests by hitting BUG_ON
in nf_nat_setup_info() and the destroy path, patches from Andrey Vagin and
me.
* Dump direction attribute in nft_ct only if it is set, from Arturo
Borrero.
* Fix IPVS bug in its own connection tracking system that may lead to
copying only 4 bytes of the IPv6 address when initializing the
ip_vs_conn object, from Michal Kubecek.
* Fix -EBUSY errors in nftables when deleting the rules, chain and tables
in a row due mixture of asynchronous and synchronous object releasing,
from me.
* Three fixes for the nf_tables set infrastructure when using intervals and
mappings, from me.
* Four patches to fixing the nf_tables log, reject and ct expressions from
the new inet table, from Patrick McHardy.
* Fix memory overrun in the map that is used to dynamically allocate names
from anonymous sets, also from Patrick.
* Fix a potential oops if you dump a set with NFPROTO_UNSPEC and a table
name, from Patrick McHardy.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
We may lost race if we flush the rule-set (which happens asynchronously
via call_rcu) and we try to remove the table (that userspace assumes
to be empty).
Fix this by recovering synchronous rule and chain deletion. This was
introduced time ago before we had no batch support, and synchronous
rule deletion performance was not good. Now that we have the batch
support, we can just postpone the purge of old rule in a second step
in the commit phase. All object deletions are synchronous after this
patch.
As a side effect, we save memory as we don't need rcu_head per rule
anymore.
Cc: Patrick McHardy <kaber@trash.net>
Reported-by: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Add a reject module for NFPROTO_INET. It does nothing but dispatch
to the AF-specific modules based on the hook family.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Currently the nft_reject module depends on symbols from ipv6. This is
wrong since no generic module should force IPv6 support to be loaded.
Split up the module into AF-specific and a generic part.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
For the reject module, we need to add AF-specific implementations to
get rid of incorrect module dependencies. Try to load an AF-specific
module first and fall back to generic modules.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
With this patch, the conntrack refcount is initially set to zero and
it is bumped once it is added to any of the list, so we fulfill
Eric's golden rule which is that all released objects always have a
refcount that equals zero.
Andrey Vagin reports that nf_conntrack_free can't be called for a
conntrack with non-zero ref-counter, because it can race with
nf_conntrack_find_get().
A conntrack slab is created with SLAB_DESTROY_BY_RCU. Non-zero
ref-counter says that this conntrack is used. So when we release
a conntrack with non-zero counter, we break this assumption.
CPU1 CPU2
____nf_conntrack_find()
nf_ct_put()
destroy_conntrack()
...
init_conntrack
__nf_conntrack_alloc (set use = 1)
atomic_inc_not_zero(&ct->use) (use = 2)
if (!l4proto->new(ct, skb, dataoff, timeouts))
nf_conntrack_free(ct); (use = 2 !!!)
...
__nf_conntrack_alloc (set use = 1)
if (!nf_ct_key_equal(h, tuple, zone))
nf_ct_put(ct); (use = 0)
destroy_conntrack()
/* continue to work with CT */
After applying the path "[PATCH] netfilter: nf_conntrack: fix RCU
race in nf_conntrack_find_get" another bug was triggered in
destroy_conntrack():
<4>[67096.759334] ------------[ cut here ]------------
<2>[67096.759353] kernel BUG at net/netfilter/nf_conntrack_core.c:211!
...
<4>[67096.759837] Pid: 498649, comm: atdd veid: 666 Tainted: G C --------------- 2.6.32-042stab084.18 #1 042stab084_18 /DQ45CB
<4>[67096.759932] RIP: 0010:[<ffffffffa03d99ac>] [<ffffffffa03d99ac>] destroy_conntrack+0x15c/0x190 [nf_conntrack]
<4>[67096.760255] Call Trace:
<4>[67096.760255] [<ffffffff814844a7>] nf_conntrack_destroy+0x17/0x30
<4>[67096.760255] [<ffffffffa03d9bb5>] nf_conntrack_find_get+0x85/0x130 [nf_conntrack]
<4>[67096.760255] [<ffffffffa03d9fb2>] nf_conntrack_in+0x352/0xb60 [nf_conntrack]
<4>[67096.760255] [<ffffffffa048c771>] ipv4_conntrack_local+0x51/0x60 [nf_conntrack_ipv4]
<4>[67096.760255] [<ffffffff81484419>] nf_iterate+0x69/0xb0
<4>[67096.760255] [<ffffffff814b5b00>] ? dst_output+0x0/0x20
<4>[67096.760255] [<ffffffff814845d4>] nf_hook_slow+0x74/0x110
<4>[67096.760255] [<ffffffff814b5b00>] ? dst_output+0x0/0x20
<4>[67096.760255] [<ffffffff814b66d5>] raw_sendmsg+0x775/0x910
<4>[67096.760255] [<ffffffff8104c5a8>] ? flush_tlb_others_ipi+0x128/0x130
<4>[67096.760255] [<ffffffff8100bc4e>] ? apic_timer_interrupt+0xe/0x20
<4>[67096.760255] [<ffffffff8100bc4e>] ? apic_timer_interrupt+0xe/0x20
<4>[67096.760255] [<ffffffff814c136a>] inet_sendmsg+0x4a/0xb0
<4>[67096.760255] [<ffffffff81444e93>] ? sock_sendmsg+0x13/0x140
<4>[67096.760255] [<ffffffff81444f97>] sock_sendmsg+0x117/0x140
<4>[67096.760255] [<ffffffff8102e299>] ? native_smp_send_reschedule+0x49/0x60
<4>[67096.760255] [<ffffffff81519beb>] ? _spin_unlock_bh+0x1b/0x20
<4>[67096.760255] [<ffffffff8109d930>] ? autoremove_wake_function+0x0/0x40
<4>[67096.760255] [<ffffffff814960f0>] ? do_ip_setsockopt+0x90/0xd80
<4>[67096.760255] [<ffffffff8100bc4e>] ? apic_timer_interrupt+0xe/0x20
<4>[67096.760255] [<ffffffff8100bc4e>] ? apic_timer_interrupt+0xe/0x20
<4>[67096.760255] [<ffffffff814457c9>] sys_sendto+0x139/0x190
<4>[67096.760255] [<ffffffff810efa77>] ? audit_syscall_entry+0x1d7/0x200
<4>[67096.760255] [<ffffffff810ef7c5>] ? __audit_syscall_exit+0x265/0x290
<4>[67096.760255] [<ffffffff81474daf>] compat_sys_socketcall+0x13f/0x210
<4>[67096.760255] [<ffffffff8104dea3>] ia32_sysret+0x0/0x5
I have reused the original title for the RFC patch that Andrey posted and
most of the original patch description.
Cc: Eric Dumazet <edumazet@google.com>
Cc: Andrew Vagin <avagin@parallels.com>
Cc: Florian Westphal <fw@strlen.de>
Reported-by: Andrew Vagin <avagin@parallels.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Andrew Vagin <avagin@parallels.com>
Thomas Gleixner
Carsten Emde
hannes@stressinduktion.org
Eric Dumazet
Daniel Borkmann
Ben Hutchings
Vlad Yasevich
Steffen Klassert
Neal Cardwell
Andrey Vagin
Eliad Peller
Dmitry Popov
Eric W. Biederman
Andy King
Vlad Yasevich
Patrick McHardy
Eric Dumazet
Andrew Lutomirski
David S. Miller
Nicolas Dichtel
Matija Glavinic Pecotic
Rashika Kheria
Pablo Neira Ayuso