There is a race between sctp_rcv() and sctp_accept() where we
have moved the association from the listening socket to the
accepted socket, but sctp_rcv() processing cached the old
socket and continues to use it.
The easy solution is to check for the socket mismatch once we've
grabed the socket lock. If we hit a mis-match, that means
that were are currently holding the lock on the listening socket,
but the association is refrencing a newly accepted socket. We need
to drop the lock on the old socket and grab the lock on the new one.
A more proper solution might be to create accepted sockets when
the new association is established, similar to TCP. That would
eliminate the race for 1-to-1 style sockets, but it would still
existing for 1-to-many sockets where a user wished to peeloff an
association. For now, we'll live with this easy solution as
it addresses the problem.
Reported-by: Michal Hocko <mhocko@suse.cz>
Reported-by: Karsten Keil <kkeil@suse.de>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
If ICMP packet too big message is received with MTU larger than current
PMTU, SCTP will still accept this ICMP message and sync the PMTU of assoc
with the wrong MTU.
Endpoing A Endpoint B
(ESTABLISHED) (ESTABLISHED)
ICMP --------->
(packet too big, MTU too larger)
sync PMTU
This patch fixed the problem by drop that ICMP message.
Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch add to validate initiate tag and chunk type if verification
tag is 0 when handling ICMP message.
RFC 4960, Appendix C. ICMP Handling
ICMP6) An implementation MUST validate that the Verification Tag
contained in the ICMP message matches the Verification Tag of the peer.
If the Verification Tag is not 0 and does NOT match, discard the ICMP
message. If it is 0 and the ICMP message contains enough bytes to
verify that the chunk type is an INIT chunk and that the Initiate Tag
matches the tag of the peer, continue with ICMP7. If the ICMP message
is too short or the chunk type or the Initiate Tag does not match,
silently discard the packet.
Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
__FUNCTION__ is gcc-specific, use __func__
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
I was notified by Randy Stewart that lksctp claims to be
"the reference implementation". First of all, "the
refrence implementation" was the original implementation
of SCTP in usersapce written ty Randy and a few others.
Second, after looking at the definiton of 'reference implementation',
we don't really meet the requirements.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
ADD-IP draft section 5.2 specifies that if an association can not
be found using the source and destination of the IP packet,
then, if the packet contains ASCONF chunks, the Address Parameter
TLV should be used to lookup an association.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The crc32c library used an identical table and algorithm
as SCTP. Switch to using the library instead of carrying
our own table. Using crypto layer proved to have too
much overhead compared to using the library directly.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch implements the receive path needed to process authenticated
chunks. Add ability to process the AUTH chunk and handle edge cases
for authenticated COOKIE-ECHO as well.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
RFC 4460 and future RFC 4960 (2960-bis) specify that packets
with bundled INIT chunks need to be dropped. We currenlty do
that only after processing any leading chunks. For OOTB chunks,
since we already walk the entire packet, we should discard packets
with bundled INITs.
There are other chunks chunks that MUST NOT be bundled, but the spec
is silent on theire treatment. Thus, we'll leave their teatment
alone for the moment.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Acked-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Forward declarion is static, the function itself is not. Make it
consistent.
Signed-off-by: Sebastian Siewior <sebastian@breakpoint.cc>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Currently, if the socket is owned by the user, we drop the ICMP
message. As a result SCTP forgets that path MTU changed and
never adjusting it's estimate. This causes all subsequent
packets to be fragmented. With this patch, we'll flag the association
that it needs to udpate it's estimate based on the already updated
routing information.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Acked-by: Sridhar Samudrala <sri@us.ibm.com>
Introduce new function sctp_transport_update_pmtu that updates
the transports and destination caches view of the path mtu.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Acked-by: Sridhar Samudrala <sri@us.ibm.com>
When a transmitted packet is looped back directly, CHECKSUM_PARTIAL
maps to the semantics of CHECKSUM_UNNECESSARY. Therefore we should
treat it as such in the stack.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
So that it is also an offset from skb->head, reduces its size from 8 to 4 bytes
on 64bit architectures, allowing us to combine the 4 bytes hole left by the
layer headers conversion, reducing struct sk_buff size to 256 bytes, i.e. 4
64byte cachelines, and since the sk_buff slab cache is SLAB_HWCACHE_ALIGN...
:-)
Many calculations that previously required that skb->{transport,network,
mac}_header be first converted to a pointer now can be done directly, being
meaningful as offsets or pointers.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Renaming skb->h to skb->transport_header, skb->nh to skb->network_header and
skb->mac to skb->mac_header, to match the names of the associated helpers
(skb[_[re]set]_{transport,network,mac}_header).
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
For consistency with all the other skb->h.raw accessors.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
For the quite common 'skb->h.raw - skb->data' sequence.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This time of the type:
skb->nh.iph = (struct iphdr *)skb->data;
That is completely equivalent to:
skb->nh.raw = skb->data;
Wonder why people love casts... :-)
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Ditto for its only caller (sctp_endpoint_is_peeled_off)
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
Along with it, statics in input.c that end up calling it
(__sctp_lookup_association, sctp_lookup_association,
__sctp_rcv_init_lookup, __sctp_rcv_lookup). Callers
are adjusted.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
The only caller (__sctp_rcv_lookup_endpoint()) also switched,
its caller adjusted
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
Every time SCTP creates a temporary association, the stack hashes it,
puts it on a list of endpoint associations and increments the backlog.
However, the lifetime of a temporary association is the processing time
of a current packet and it's destroyed after that. In fact, we don't
really want anyone else finding this association. There is no reason to
do this extra work.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
I was looking at a RHEL5 bug report involving Xen and SCTP
(https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=212550).
It turns out that SCTP wasn't written to handle skb fragments at
all. The absence of any calls to skb_may_pull is testament to
that.
It just so happens that Xen creates fragmented packets more often
than other scenarios (header & data split when going from domU to
dom0). That's what caused this bug to show up.
Until someone has the time sits down and audits the entire net/sctp
directory, here is a conservative and safe solution that simply
linearises all packets on input.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
We only need the timestamp on COOKIE-ECHO chunks, so instead of always
timestamping every SCTP packet, let common code timestamp if the socket
option is set. For COOKIE-ECHO, simply get the time of day if we don't
have a timestamp. This introduces a small possibility that the cookie
may be considered expired, but it will be renegotiated.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Function sk_filter() is called from tcp_v{4,6}_rcv() functions with arg
needlock = 0, while socket is not locked at that moment. In order to avoid
this and similar issues in the future, use rcu for sk->sk_filter field read
protection.
Signed-off-by: Dmitry Mishin <dim@openvz.org>
Signed-off-by: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Signed-off-by: Kirill Korotaev <dev@openvz.org>
This patch adds more statistics info under /proc/net/sctp/snmp
that should be useful for debugging. The additional events that
are counted now include timer expirations, retransmits, packet
and data chunk discards.
The Data chunk discards include all the cases where a data chunk
is discarded including high tsn, bad stream, dup tsn and the most
useful one(out of receive buffer/rwnd).
Also moved the SCTP MIB data structures from the generic include
directories to include/sctp/sctp.h.
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
sctp_rcv().
The goal is to hold the ref on the association/endpoint throughout the
state-machine process. We accomplish like this:
/* ref on the assoc/ep is taken during lookup */
if owned_by_user(sk)
sctp_add_backlog(skb, sk);
else
inqueue_push(skb, sk);
/* drop the ref on the assoc/ep */
However, in sctp_add_backlog() we take the ref on assoc/ep and hold it
while the skb is on the backlog queue. This allows us to get rid of the
sock_hold/sock_put in the lookup routines.
Now sctp_backlog_rcv() needs to account for potential association move.
In the unlikely event that association moved, we need to retest if the
new socket is locked by user. If we don't this, we may have two packets
racing up the stack toward the same socket and we can't deal with it.
If the new socket is still locked, we'll just add the skb to its backlog
continuing to hold the ref on the association. This get's rid of the
need to move packets from one backlog to another and it also safe in
case new packets arrive on the same backlog queue.
The last step, is to lock the new socket when we are moving the
association to it. This is needed in case any new packets arrive on
the association when it moved. We want these to go to the backlog since
we would like to avoid the race between this new packet and a packet
that may be sitting on the backlog queue of the old socket toward the
same association.
Signed-off-by: Vladislav Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
I was working on the ipip/xfrm problem and as usual I get side-tracked by
other problems.
As part of an attempt to change the IPv4 protocol handler calling
convention I found that SCTP violated the existing convention.
It's returning non-zero values after freeing the skb. This is doubly bad
as 1) the skb gets resubmitted; 2) the return value is interpreted as a
protocol number.
This patch changes those return values to zero.
IPv6 doesn't suffer from this problem because it uses a positive return
value as an indication for resubmission. So the only effect of this patch
there is to increment the IPSTATS_MIB_INDELIVERS counter which IMHO is
the right thing to do.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Validate and update the sk in sctp_rcv() to avoid the race where an
assoc/ep could move to a different socket after we get the sk, but before
the skb is added to the backlog.
Also migrate the skb's in backlog queue to new sk when doing a peeloff.
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Do not release the reference to association/endpoint if an incoming skb is
added to backlog. Instead release it after the chunk is processed in
sctp_backlog_rcv().
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
