linux-stable.git/include/net/sctp, branch v3.10.78

net: sctp: fix skb_over_panic when receiving malformed ASCONF chunks

2014-11-21T17:22:55+00:00

commit 9de7922bc709eee2f609cd01d98aaedc4cf5ea74 upstream.

Commit 6f4c618ddb0 ("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:
 ------------[ cut here ]------------
kernel BUG at net/core/skbuff.c:129!
[...]
Call Trace:
 
 [] skb_put+0x5c/0x70
 [] sctp_addto_chunk+0x63/0xd0 [sctp]
 [] sctp_process_asconf+0x1af/0x540 [sctp]
 [] ? _read_unlock_bh+0x15/0x20
 [] sctp_sf_do_asconf+0x168/0x240 [sctp]
 [] sctp_do_sm+0x71/0x1210 [sctp]
 [] ? fib_rules_lookup+0xad/0xf0
 [] ? sctp_cmp_addr_exact+0x32/0x40 [sctp]
 [] sctp_assoc_bh_rcv+0xd3/0x180 [sctp]
 [] sctp_inq_push+0x56/0x80 [sctp]
 [] sctp_rcv+0x982/0xa10 [sctp]
 [] ? ipt_local_in_hook+0x23/0x28 [iptable_filter]
 [] ? nf_iterate+0x69/0xb0
 [] ? ip_local_deliver_finish+0x0/0x2d0
 [] ? nf_hook_slow+0x76/0x120
 [] ? ip_local_deliver_finish+0x0/0x2d0
 [] ip_local_deliver_finish+0xdd/0x2d0
 [] ip_local_deliver+0x98/0xa0
 [] ip_rcv_finish+0x12d/0x440
 [] ip_rcv+0x275/0x350
 [] __netif_receive_skb+0x4ab/0x750
 [] 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 
Signed-off-by: Vlad Yasevich 
Acked-by: Neil Horman 
Signed-off-by: David S. Miller 
Cc: Josh Boyer 
Signed-off-by: Greg Kroah-Hartman

net: sctp: fix panic on duplicate ASCONF chunks

2014-11-21T17:22:55+00:00

commit b69040d8e39f20d5215a03502a8e8b4c6ab78395 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 2e3216cd54b1
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: 2e3216cd54b1 ("sctp: Follow security requirement of responding with 1 packet")
Signed-off-by: Daniel Borkmann 
Signed-off-by: Vlad Yasevich 
Signed-off-by: David S. Miller 
Cc: Josh Boyer 
Signed-off-by: Greg Kroah-Hartman

sctp: handle association restarts when the socket is closed.

2014-10-15T06:31:57+00:00

[ Upstream commit bdf6fa52f01b941d4a80372d56de465bdbbd1d23 ]

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 
Signed-off-by: Vlad Yasevich 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: sctp: cache auth_enable per endpoint

2014-05-31T04:52:15+00:00

[ Upstream commit b14878ccb7fac0242db82720b784ab62c467c0dc ]

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:
[] sctp_auth_asoc_set_default_hmac+0x68/0x80
[] sctp_process_init+0x5e0/0x8a4
[] sctp_sf_do_5_1B_init+0x234/0x34c
[] sctp_do_sm+0xb4/0x1e8
[] sctp_endpoint_bh_rcv+0x1c4/0x214
[] sctp_rcv+0x588/0x630
[] sctp6_rcv+0x10/0x24
[] ip6_input+0x2c0/0x440
[] __netif_receive_skb_core+0x4a8/0x564
[] process_backlog+0xb4/0x18c
[] net_rx_action+0x12c/0x210
[] __do_softirq+0x17c/0x2ac
[] irq_exit+0x54/0xb0
[] ret_from_irq+0x0/0x4
[] rm7k_wait_irqoff+0x24/0x48
[] cpu_startup_entry+0xc0/0x148
[] start_kernel+0x37c/0x398
Code: dd0900b8  000330f8  0126302d  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 
Signed-off-by: Vlad Yasevich 
Signed-off-by: Daniel Borkmann 
Acked-by: Neil Horman 
Tested-by: Joshua Kinard 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next

2013-05-01T21:08:52+00:00

Pull networking updates from David Miller:
 "Highlights (1721 non-merge commits, this has to be a record of some
  sort):

   1) Add 'random' mode to team driver, from Jiri Pirko and Eric
      Dumazet.

   2) Make it so that any driver that supports configuration of multiple
      MAC addresses can provide the forwarding database add and del
      calls by providing a default implementation and hooking that up if
      the driver doesn't have an explicit set of handlers.  From Vlad
      Yasevich.

   3) Support GSO segmentation over tunnels and other encapsulating
      devices such as VXLAN, from Pravin B Shelar.

   4) Support L2 GRE tunnels in the flow dissector, from Michael Dalton.

   5) Implement Tail Loss Probe (TLP) detection in TCP, from Nandita
      Dukkipati.

   6) In the PHY layer, allow supporting wake-on-lan in situations where
      the PHY registers have to be written for it to be configured.

      Use it to support wake-on-lan in mv643xx_eth.

      From Michael Stapelberg.

   7) Significantly improve firewire IPV6 support, from YOSHIFUJI
      Hideaki.

   8) Allow multiple packets to be sent in a single transmission using
      network coding in batman-adv, from Martin Hundebøll.

   9) Add support for T5 cxgb4 chips, from Santosh Rastapur.

  10) Generalize the VXLAN forwarding tables so that there is more
      flexibility in configurating various aspects of the endpoints.
      From David Stevens.

  11) Support RSS and TSO in hardware over GRE tunnels in bxn2x driver,
      from Dmitry Kravkov.

  12) Zero copy support in nfnelink_queue, from Eric Dumazet and Pablo
      Neira Ayuso.

  13) Start adding networking selftests.

  14) In situations of overload on the same AF_PACKET fanout socket, or
      per-cpu packet receive queue, minimize drop by distributing the
      load to other cpus/fanouts.  From Willem de Bruijn and Eric
      Dumazet.

  15) Add support for new payload offset BPF instruction, from Daniel
      Borkmann.

  16) Convert several drivers over to mdoule_platform_driver(), from
      Sachin Kamat.

  17) Provide a minimal BPF JIT image disassembler userspace tool, from
      Daniel Borkmann.

  18) Rewrite F-RTO implementation in TCP to match the final
      specification of it in RFC4138 and RFC5682.  From Yuchung Cheng.

  19) Provide netlink socket diag of netlink sockets ("Yo dawg, I hear
      you like netlink, so I implemented netlink dumping of netlink
      sockets.") From Andrey Vagin.

  20) Remove ugly passing of rtnetlink attributes into rtnl_doit
      functions, from Thomas Graf.

  21) Allow userspace to be able to see if a configuration change occurs
      in the middle of an address or device list dump, from Nicolas
      Dichtel.

  22) Support RFC3168 ECN protection for ipv6 fragments, from Hannes
      Frederic Sowa.

  23) Increase accuracy of packet length used by packet scheduler, from
      Jason Wang.

  24) Beginning set of changes to make ipv4/ipv6 fragment handling more
      scalable and less susceptible to overload and locking contention,
      from Jesper Dangaard Brouer.

  25) Get rid of using non-type-safe NLMSG_* macros and use nlmsg_*()
      instead.  From Hong Zhiguo.

  26) Optimize route usage in IPVS by avoiding reference counting where
      possible, from Julian Anastasov.

  27) Convert IPVS schedulers to RCU, also from Julian Anastasov.

  28) Support cpu fanouts in xt_NFQUEUE netfilter target, from Holger
      Eitzenberger.

  29) Network namespace support for nf_log, ebt_log, xt_LOG, ipt_ULOG,
      nfnetlink_log, and nfnetlink_queue.  From Gao feng.

  30) Implement RFC3168 ECN protection, from Hannes Frederic Sowa.

  31) Support several new r8169 chips, from Hayes Wang.

  32) Support tokenized interface identifiers in ipv6, from Daniel
      Borkmann.

  33) Use usbnet_link_change() helper in USB net driver, from Ming Lei.

  34) Add 802.1ad vlan offload support, from Patrick McHardy.

  35) Support mmap() based netlink communication, also from Patrick
      McHardy.

  36) Support HW timestamping in mlx4 driver, from Amir Vadai.

  37) Rationalize AF_PACKET packet timestamping when transmitting, from
      Willem de Bruijn and Daniel Borkmann.

  38) Bring parity to what's provided by /proc/net/packet socket dumping
      and the info provided by netlink socket dumping of AF_PACKET
      sockets.  From Nicolas Dichtel.

  39) Fix peeking beyond zero sized SKBs in AF_UNIX, from Benjamin
      Poirier"

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1722 commits)
  filter: fix va_list build error
  af_unix: fix a fatal race with bit fields
  bnx2x: Prevent memory leak when cnic is absent
  bnx2x: correct reading of speed capabilities
  net: sctp: attribute printl with __printf for gcc fmt checks
  netlink: kconfig: move mmap i/o into netlink kconfig
  netpoll: convert mutex into a semaphore
  netlink: Fix skb ref counting.
  net_sched: act_ipt forward compat with xtables
  mlx4_en: fix a build error on 32bit arches
  Revert "bnx2x: allow nvram test to run when device is down"
  bridge: avoid OOPS if root port not found
  drivers: net: cpsw: fix kernel warn on cpsw irq enable
  sh_eth: use random MAC address if no valid one supplied
  3c509.c: call SET_NETDEV_DEV for all device types (ISA/ISAPnP/EISA)
  tg3: fix to append hardware time stamping flags
  unix/stream: fix peeking with an offset larger than data in queue
  unix/dgram: fix peeking with an offset larger than data in queue
  unix/dgram: peek beyond 0-sized skbs
  openvswitch: Remove unneeded ovs_netdev_get_ifindex()
  ...

sctp: Correct type and usage of sctp_end_cksum()

2013-04-29T18:09:08+00:00

Change the type of the crc32 parameter of sctp_end_cksum()
from __be32 to __u32 to reflect that fact that it is passed
to cpu_to_le32().

There are five in-tree users of sctp_end_cksum().
The following four had warnings flagged by sparse which are
no longer present with this change.

net/netfilter/ipvs/ip_vs_proto_sctp.c:sctp_nat_csum()
net/netfilter/ipvs/ip_vs_proto_sctp.c:sctp_csum_check()
net/sctp/input.c:sctp_rcv_checksum()
net/sctp/output.c:sctp_packet_transmit()

The fifth user is net/netfilter/nf_nat_proto_sctp.c:sctp_manip_pkt().
It has been updated to pass a __u32 instead of a __be32,
the value in question was already calculated in cpu byte-order.

net/netfilter/nf_nat_proto_sctp.c:sctp_manip_pkt() has also
been updated to assign the return value of sctp_end_cksum()
directly to a variable of type __le32, matching the
type of the return value. Previously the return value
was assigned to a variable of type __be32 and then that variable
was finally assigned to another variable of type __le32.

Problems flagged by sparse.
Compile and sparse tested only.

Signed-off-by: Simon Horman 
Signed-off-by: Pablo Neira Ayuso

net: sctp: minor: remove dead code from sctp_packet

2013-04-22T20:25:21+00:00

struct sctp_packet is currently embedded into sctp_transport or
sits on the stack as 'singleton' in sctp_outq_flush(). Therefore,
its member 'malloced' is always 0, thus a kfree() is never called.
Because of that, we can just remove this code.

Signed-off-by: Daniel Borkmann 
Signed-off-by: David S. Miller

net: sctp: sctp_ulpq: remove 'malloced' struct member

2013-04-17T18:13:02+00:00

The structure sctp_ulpq is embedded into sctp_association and never
separately allocated, also ulpq->malloced is always 0, so that
kfree() is never called. Therefore, remove this code.

Signed-off-by: Daniel Borkmann 
Acked-by: Neil Horman 
Signed-off-by: David S. Miller

net: sctp: sctp_bind_addr: remove dead code

2013-04-17T18:13:02+00:00

The sctp_bind_addr structure has a 'malloced' member that is
always set to 0, thus in sctp_bind_addr_free() the kfree()
part can never be called. This part is embedded into
sctp_ep_common anyway and never alloced.

Signed-off-by: Daniel Borkmann 
Acked-by: Neil Horman 
Signed-off-by: David S. Miller

net: sctp: sctp_transport: remove unused variable

2013-04-17T18:13:02+00:00

sctp_transport's member 'malloced' is set to 1, never evaluated
and the structure is kfreed anyway. So just remove it.

Signed-off-by: Daniel Borkmann 
Acked-by: Neil Horman 
Signed-off-by: David S. Miller