linux-toradex.git/net/sctp/input.c, branch v2.6.32.56

sctp: Fix a race between ICMP protocol unreachable and connect()

2011-01-07T22:43:18+00:00

commit 50b5d6ad63821cea324a5a7a19854d4de1a0a819 upstream.

ICMP protocol unreachable handling completely disregarded
the fact that the user may have locked the socket.  It proceeded
to destroy the association, even though the user may have
held the lock and had a ref on the association.  This resulted
in the following:

Attempt to release alive inet socket f6afcc00

=========================
[ BUG: held lock freed! ]
-------------------------
somenu/2672 is freeing memory f6afcc00-f6afcfff, with a lock still held
there!
 (sk_lock-AF_INET){+.+.+.}, at: [] sctp_connect+0x13/0x4c
1 lock held by somenu/2672:
 #0:  (sk_lock-AF_INET){+.+.+.}, at: [] sctp_connect+0x13/0x4c

stack backtrace:
Pid: 2672, comm: somenu Not tainted 2.6.32-telco #55
Call Trace:
 [] ? printk+0xf/0x11
 [] debug_check_no_locks_freed+0xce/0xff
 [] kmem_cache_free+0x21/0x66
 [] __sk_free+0x9d/0xab
 [] sk_free+0x1c/0x1e
 [] sctp_association_put+0x32/0x89
 [] __sctp_connect+0x36d/0x3f4
 [] ? sctp_connect+0x13/0x4c
 [] ? autoremove_wake_function+0x0/0x33
 [] sctp_connect+0x31/0x4c
 [] inet_dgram_connect+0x4b/0x55
 [] sys_connect+0x54/0x71
 [] ? lock_release_non_nested+0x88/0x239
 [] ? might_fault+0x42/0x7c
 [] ? might_fault+0x42/0x7c
 [] sys_socketcall+0x6d/0x178
 [] ? trace_hardirqs_on_thunk+0xc/0x10
 [] syscall_call+0x7/0xb

This was because the sctp_wait_for_connect() would aqcure the socket
lock and then proceed to release the last reference count on the
association, thus cause the fully destruction path to finish freeing
the socket.

The simplest solution is to start a very short timer in case the socket
is owned by user.  When the timer expires, we can do some verification
and be able to do the release properly.

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

sctp: Use frag list abstraction interfaces.

2009-06-09T07:24:07+00:00

Signed-off-by: David S. Miller

sctp: Clean up sctp checksumming code

2009-02-16T08:03:10+00:00

The sctp crc32c checksum is always generated in little endian.
So, we clean up the code to treat it as little endian and remove
all the __force casts.

Suggested by Herbert Xu.

Signed-off-by: Vlad Yasevich 
Signed-off-by: David S. Miller

sctp: Allow to disable SCTP checksums via module parameter

2009-02-16T08:03:09+00:00

This is a new version of my patch, now using a module parameter instead
of a sysctl, so that the option is harder to find. Please note that,
once the module is loaded, it is still possible to change the value of
the parameter in /sys/module/sctp/parameters/, which is useful if you
want to do performance comparisons without rebooting.

Computation of SCTP checksums significantly affects the performance of
SCTP. For example, using two dual-Opteron 246 connected using a Gbe
network, it was not possible to achieve more than ~730 Mbps, compared to
941 Mbps after disabling SCTP checksums.
Unfortunately, SCTP checksum offloading in NICs is not commonly
available (yet).

By default, checksums are still enabled, of course.

Signed-off-by: Lucas Nussbaum 
Signed-off-by: Vlad Yasevich 
Signed-off-by: David S. Miller

sctp: Fix another socket race during accept/peeloff

2009-01-22T22:53:23+00:00

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 
Reported-by: Karsten Keil 
Signed-off-by: Vlad Yasevich 
Signed-off-by: David S. Miller

sctp: Drop ICMP packet too big message with MTU larger than current PMTU

2008-10-23T07:59:52+00:00

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 
Signed-off-by: Vlad Yasevich 
Signed-off-by: David S. Miller

sctp: remove unnecessary byteshifting, calculate directly in big-endian

2008-07-19T06:07:09+00:00

Signed-off-by: Harvey Harrison 
Signed-off-by: Vlad Yasevich 
Signed-off-by: David S. Miller

mib: add net to NET_INC_STATS_BH

2008-07-17T03:31:16+00:00

Signed-off-by: Pavel Emelyanov 
Signed-off-by: David S. Miller

mib: add struct net to ICMP_INC_STATS_BH

2008-07-15T06:05:29+00:00

Signed-off-by: Pavel Emelyanov 
Signed-off-by: David S. Miller

sctp: Validate Initiate Tag when handling ICMP message

2008-06-19T23:07:48+00:00

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 
Signed-off-by: Vlad Yasevich 
Signed-off-by: David S. Miller