linux-toradex.git/net/sctp, branch v3.4.67

net: sctp: fix ipv6 ipsec encryption bug in sctp_v6_xmit

2013-10-13T22:42:47+00:00

[ Upstream commit 95ee62083cb6453e056562d91f597552021e6ae7 ]

Alan Chester reported an issue with IPv6 on SCTP that IPsec traffic is not
being encrypted, whereas on IPv4 it is. Setting up an AH + ESP transport
does not seem to have the desired effect:

SCTP + IPv4:

  22:14:20.809645 IP (tos 0x2,ECT(0), ttl 64, id 0, offset 0, flags [DF], proto AH (51), length 116)
    192.168.0.2 > 192.168.0.5: AH(spi=0x00000042,sumlen=16,seq=0x1): ESP(spi=0x00000044,seq=0x1), length 72
  22:14:20.813270 IP (tos 0x2,ECT(0), ttl 64, id 0, offset 0, flags [DF], proto AH (51), length 340)
    192.168.0.5 > 192.168.0.2: AH(spi=0x00000043,sumlen=16,seq=0x1):

SCTP + IPv6:

  22:31:19.215029 IP6 (class 0x02, hlim 64, next-header SCTP (132) payload length: 364)
    fe80::222:15ff:fe87:7fc.3333 > fe80::92e6:baff:fe0d:5a54.36767: sctp
    1) [INIT ACK] [init tag: 747759530] [rwnd: 62464] [OS: 10] [MIS: 10]

Moreover, Alan says:

  This problem was seen with both Racoon and Racoon2. Other people have seen
  this with OpenSwan. When IPsec is configured to encrypt all upper layer
  protocols the SCTP connection does not initialize. After using Wireshark to
  follow packets, this is because the SCTP packet leaves Box A unencrypted and
  Box B believes all upper layer protocols are to be encrypted so it drops
  this packet, causing the SCTP connection to fail to initialize. When IPsec
  is configured to encrypt just SCTP, the SCTP packets are observed unencrypted.

In fact, using `socat sctp6-listen:3333 -` on one end and transferring "plaintext"
string on the other end, results in cleartext on the wire where SCTP eventually
does not report any errors, thus in the latter case that Alan reports, the
non-paranoid user might think he's communicating over an encrypted transport on
SCTP although he's not (tcpdump ... -X):

  ...
  0x0030: 5d70 8e1a 0003 001a 177d eb6c 0000 0000  ]p.......}.l....
  0x0040: 0000 0000 706c 6169 6e74 6578 740a 0000  ....plaintext...

Only in /proc/net/xfrm_stat we can see XfrmInTmplMismatch increasing on the
receiver side. Initial follow-up analysis from Alan's bug report was done by
Alexey Dobriyan. Also thanks to Vlad Yasevich for feedback on this.

SCTP has its own implementation of sctp_v6_xmit() not calling inet6_csk_xmit().
This has the implication that it probably never really got updated along with
changes in inet6_csk_xmit() and therefore does not seem to invoke xfrm handlers.

SCTP's IPv4 xmit however, properly calls ip_queue_xmit() to do the work. Since
a call to inet6_csk_xmit() would solve this problem, but result in unecessary
route lookups, let us just use the cached flowi6 instead that we got through
sctp_v6_get_dst(). Since all SCTP packets are being sent through sctp_packet_transmit(),
we do the route lookup / flow caching in sctp_transport_route(), hold it in
tp->dst and skb_dst_set() right after that. If we would alter fl6->daddr in
sctp_v6_xmit() to np->opt->srcrt, we possibly could run into the same effect
of not having xfrm layer pick it up, hence, use fl6_update_dst() in sctp_v6_get_dst()
instead to get the correct source routed dst entry, which we assign to the skb.

Also source address routing example from 625034113 ("sctp: fix sctp to work with
ipv6 source address routing") still works with this patch! Nevertheless, in RFC5095
it is actually 'recommended' to not use that anyway due to traffic amplification [1].
So it seems we're not supposed to do that anyway in sctp_v6_xmit(). Moreover, if
we overwrite the flow destination here, the lower IPv6 layer will be unable to
put the correct destination address into IP header, as routing header is added in
ipv6_push_nfrag_opts() but then probably with wrong final destination. Things aside,
result of this patch is that we do not have any XfrmInTmplMismatch increase plus on
the wire with this patch it now looks like:

SCTP + IPv6:

  08:17:47.074080 IP6 2620:52:0:102f:7a2b:cbff:fe27:1b0a > 2620:52:0:102f:213:72ff:fe32:7eba:
    AH(spi=0x00005fb4,seq=0x1): ESP(spi=0x00005fb5,seq=0x1), length 72
  08:17:47.074264 IP6 2620:52:0:102f:213:72ff:fe32:7eba > 2620:52:0:102f:7a2b:cbff:fe27:1b0a:
    AH(spi=0x00003d54,seq=0x1): ESP(spi=0x00003d55,seq=0x1), length 296

This fixes Kernel Bugzilla 24412. This security issue seems to be present since
2.6.18 kernels. Lets just hope some big passive adversary in the wild didn't have
its fun with that. lksctp-tools IPv6 regression test suite passes as well with
this patch.

 [1] http://www.secdev.org/conf/IPv6_RH_security-csw07.pdf

Reported-by: Alan Chester 
Reported-by: Alexey Dobriyan 
Signed-off-by: Daniel Borkmann 
Cc: Steffen Klassert 
Cc: Hannes Frederic Sowa 
Acked-by: Vlad Yasevich 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: sctp: fix smatch warning in sctp_send_asconf_del_ip

2013-10-13T22:42:47+00:00

[ Upstream commit 88362ad8f9a6cea787420b57cc27ccacef000dbe ]

This was originally reported in [1] and posted by Neil Horman [2], he said:

  Fix up a missed null pointer check in the asconf code. If we don't find
  a local address, but we pass in an address length of more than 1, we may
  dereference a NULL laddr pointer. Currently this can't happen, as the only
  users of the function pass in the value 1 as the addrcnt parameter, but
  its not hot path, and it doesn't hurt to check for NULL should that ever
  be the case.

The callpath from sctp_asconf_mgmt() looks okay. But this could be triggered
from sctp_setsockopt_bindx() call with SCTP_BINDX_REM_ADDR and addrcnt > 1
while passing all possible addresses from the bind list to SCTP_BINDX_REM_ADDR
so that we do *not* find a single address in the association's bind address
list that is not in the packed array of addresses. If this happens when we
have an established association with ASCONF-capable peers, then we could get
a NULL pointer dereference as we only check for laddr == NULL && addrcnt == 1
and call later sctp_make_asconf_update_ip() with NULL laddr.

BUT: this actually won't happen as sctp_bindx_rem() will catch such a case
and return with an error earlier. As this is incredably unintuitive and error
prone, add a check to catch at least future bugs here. As Neil says, its not
hot path. Introduced by 8a07eb0a5 ("sctp: Add ASCONF operation on the
single-homed host").

 [1] http://www.spinics.net/lists/linux-sctp/msg02132.html
 [2] http://www.spinics.net/lists/linux-sctp/msg02133.html

Reported-by: Dan Carpenter 
Signed-off-by: Neil Horman 
Signed-off-by: Daniel Borkmann 
Cc: Michio Honda 
Acked-By: Neil Horman 
Acked-by: Vlad Yasevich 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

Revert "sctp: fix call to SCTP_CMD_PROCESS_SACK in sctp_cmd_interpreter()"

2013-10-01T16:10:50+00:00

This reverts commit c2f5b7507ac5d808f29287d77ee6148358d7fbfe which is
commit f6e80abeab928b7c47cc1fbf53df13b4398a2bec.

Michal writes:
	Mainline commit f6e80abe was introduced in v3.7-rc2 as a
	follow-up fix to commit

	  edfee033  sctp: check src addr when processing SACK to update transport state

	(from v3.7-rc1) which changed the interpretation of third
	argument to sctp_cmd_process_sack() and sctp_outq_sack(). But as
	commit edfee033 has never been backported to stable branches,
	backport of commit f6e80abe actually breaks the code rather than
	fixing it.

Reported-by: Michal Kubecek 
Cc: Zijie Pan 
Cc: Nicolas Dichtel 
Cc: Vlad Yasevich 
Acked-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

sctp: fully initialize sctp_outq in sctp_outq_init

2013-08-11T22:38:44+00:00

[ Upstream commit c5c7774d7eb4397891edca9ebdf750ba90977a69 ]

In commit 2f94aabd9f6c925d77aecb3ff020f1cc12ed8f86
(refactor sctp_outq_teardown to insure proper re-initalization)
we modified sctp_outq_teardown to use sctp_outq_init to fully re-initalize the
outq structure.  Steve West recently asked me why I removed the q->error = 0
initalization from sctp_outq_teardown.  I did so because I was operating under
the impression that sctp_outq_init would properly initalize that value for us,
but it doesn't.  sctp_outq_init operates under the assumption that the outq
struct is all 0's (as it is when called from sctp_association_init), but using
it in __sctp_outq_teardown violates that assumption. We should do a memset in
sctp_outq_init to ensure that the entire structure is in a known state there
instead.

Signed-off-by: Neil Horman 
Reported-by: "West, Steve (NSN - US/Fort Worth)" 
CC: Vlad Yasevich 
CC: netdev@vger.kernel.org
CC: davem@davemloft.net
Acked-by: Vlad Yasevich 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: sctp: fix NULL pointer dereference in socket destruction

2013-06-27T18:27:32+00:00

[ Upstream commit 1abd165ed757db1afdefaac0a4bc8a70f97d258c ]

While stress testing sctp sockets, I hit the following panic:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000020
IP: [] sctp_endpoint_free+0xe/0x40 [sctp]
PGD 7cead067 PUD 7ce76067 PMD 0
Oops: 0000 [#1] SMP
Modules linked in: sctp(F) libcrc32c(F) [...]
CPU: 7 PID: 2950 Comm: acc Tainted: GF            3.10.0-rc2+ #1
Hardware name: Dell Inc. PowerEdge T410/0H19HD, BIOS 1.6.3 02/01/2011
task: ffff88007ce0e0c0 ti: ffff88007b568000 task.ti: ffff88007b568000
RIP: 0010:[]  [] sctp_endpoint_free+0xe/0x40 [sctp]
RSP: 0018:ffff88007b569e08  EFLAGS: 00010292
RAX: 0000000000000000 RBX: ffff88007db78a00 RCX: dead000000200200
RDX: ffffffffa049fdb0 RSI: ffff8800379baf38 RDI: 0000000000000000
RBP: ffff88007b569e18 R08: ffff88007c230da0 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffff880077990d00 R14: 0000000000000084 R15: ffff88007db78a00
FS:  00007fc18ab61700(0000) GS:ffff88007fc60000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000000000000020 CR3: 000000007cf9d000 CR4: 00000000000007e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Stack:
 ffff88007b569e38 ffff88007db78a00 ffff88007b569e38 ffffffffa049fded
 ffffffff81abf0c0 ffff88007db78a00 ffff88007b569e58 ffffffff8145b60e
 0000000000000000 0000000000000000 ffff88007b569eb8 ffffffff814df36e
Call Trace:
 [] sctp_destroy_sock+0x3d/0x80 [sctp]
 [] sk_common_release+0x1e/0xf0
 [] inet_create+0x2ae/0x350
 [] __sock_create+0x11f/0x240
 [] sock_create+0x30/0x40
 [] SyS_socket+0x4c/0xc0
 [] ? do_page_fault+0xe/0x10
 [] ? page_fault+0x22/0x30
 [] system_call_fastpath+0x16/0x1b
Code: 0c c9 c3 66 2e 0f 1f 84 00 00 00 00 00 e8 fb fe ff ff c9 c3 66 0f
      1f 84 00 00 00 00 00 55 48 89 e5 53 48 83 ec 08 66 66 66 66 90 <48>
      8b 47 20 48 89 fb c6 47 1c 01 c6 40 12 07 e8 9e 68 01 00 48
RIP  [] sctp_endpoint_free+0xe/0x40 [sctp]
 RSP 
CR2: 0000000000000020
---[ end trace e0d71ec1108c1dd9 ]---

I did not hit this with the lksctp-tools functional tests, but with a
small, multi-threaded test program, that heavily allocates, binds,
listens and waits in accept on sctp sockets, and then randomly kills
some of them (no need for an actual client in this case to hit this).
Then, again, allocating, binding, etc, and then killing child processes.

This panic then only occurs when ``echo 1 > /proc/sys/net/sctp/auth_enable''
is set. The cause for that is actually very simple: in sctp_endpoint_init()
we enter the path of sctp_auth_init_hmacs(). There, we try to allocate
our crypto transforms through crypto_alloc_hash(). In our scenario,
it then can happen that crypto_alloc_hash() fails with -EINTR from
crypto_larval_wait(), thus we bail out and release the socket via
sk_common_release(), sctp_destroy_sock() and hit the NULL pointer
dereference as soon as we try to access members in the endpoint during
sctp_endpoint_free(), since endpoint at that time is still NULL. Now,
if we have that case, we do not need to do any cleanup work and just
leave the destruction handler.

Signed-off-by: Daniel Borkmann 
Acked-by: Neil Horman 
Acked-by: Vlad Yasevich 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: sctp: sctp_auth_key_put: use kzfree instead of kfree

2013-05-01T16:41:08+00:00

[ Upstream commit 586c31f3bf04c290dc0a0de7fc91d20aa9a5ee53 ]

For sensitive data like keying material, it is common practice to zero
out keys before returning the memory back to the allocator. Thus, use
kzfree instead of kfree.

Signed-off-by: Daniel Borkmann 
Acked-by: Neil Horman 
Acked-by: Vlad Yasevich 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

sctp: don't break the loop while meeting the active_path so as to find the matched transport

2013-03-28T19:11:53+00:00

[ Upstream commit 2317f449af30073cfa6ec8352e4a65a89e357bdd ]

sctp_assoc_lookup_tsn() function searchs which transport a certain TSN
was sent on, if not found in the active_path transport, then go search
all the other transports in the peer's transport_addr_list, however, we
should continue to the next entry rather than break the loop when meet
the active_path transport.

Signed-off-by: Xufeng Zhang 
Acked-by: Neil Horman 
Acked-by: Vlad Yasevich 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

sctp: Use correct sideffect command in duplicate cookie handling

2013-03-28T19:11:53+00:00

[ Upstream commit f2815633504b442ca0b0605c16bf3d88a3a0fcea ]

When SCTP is done processing a duplicate cookie chunk, it tries
to delete a newly created association.  For that, it has to set
the right association for the side-effect processing to work.
However, when it uses the SCTP_CMD_NEW_ASOC command, that performs
more work then really needed (like hashing the associationa and
assigning it an id) and there is no point to do that only to
delete the association as a next step.  In fact, it also creates
an impossible condition where an association may be found by
the getsockopt() call, and that association is empty.  This
causes a crash in some sctp getsockopts.

The solution is rather simple.  We simply use SCTP_CMD_SET_ASOC
command that doesn't have all the overhead and does exactly
what we need.

Reported-by: Karl Heiss 
Tested-by: Karl Heiss 
CC: Neil Horman 
Signed-off-by: Vlad Yasevich 
Acked-by: Neil Horman 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: sctp: sctp_endpoint_free: zero out secret key data

2013-02-14T18:49:06+00:00

[ Upstream commit b5c37fe6e24eec194bb29d22fdd55d73bcc709bf ]

On sctp_endpoint_destroy, previously used sensitive keying material
should be zeroed out before the memory is returned, as we already do
with e.g. auth keys when released.

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

net: sctp: sctp_setsockopt_auth_key: use kzfree instead of kfree

2013-02-14T18:49:05+00:00

[ Upstream commit 6ba542a291a5e558603ac51cda9bded347ce7627 ]

In sctp_setsockopt_auth_key, we create a temporary copy of the user
passed shared auth key for the endpoint or association and after
internal setup, we free it right away. Since it's sensitive data, we
should zero out the key before returning the memory back to the
allocator. Thus, use kzfree instead of kfree, just as we do in
sctp_auth_key_put().

Signed-off-by: Daniel Borkmann 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman