check_compat_entry_size_and_hooks iterates over the matches and calls
compat_check_calc_match, which loads the match and calculates the
compat offsets, but unlike the non-compat version, doesn't call
->checkentry yet. On error however it calls cleanup_matches, which in
turn calls ->destroy, which can result in crashes if the destroy
function (validly) expects to only get called after the checkentry
function.

Add a compat_release_match function that only drops the module reference
on error and rename compat_check_calc_match to compat_find_calc_match to
reflect the fact that it doesn't call the checkentry function.

Reported by Jan Engelhardt <jengelh@linux01.gwdg.de>

Signed-off-by: Dmitry Mishin <dim@openvz.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

When a helper module is unloaded all conntracks refering to it have their
helper pointer NULLed out, leading to lots of races. In most places this
can be fixed by proper use of RCU (they do already check for != NULL,
but in a racy way), additionally nf_conntrack_expect_related needs to
bail out when no helper is present.

Also remove two paranoid BUG_ONs in nf_conntrack_proto_gre that are racy
and not worth fixing.

Signed-off-by: Patrick McHarrdy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

They're the same.

Signed-off-by: Jing Min Zhao <zhaojingmin@vivecode.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

When the packet size is changed by the FTP NAT helper, the connection
tracking helper adjusts the sequence number of the newline character
by the size difference. This is wrong because NAT sequence number
adjustment happens after helpers are called, so the unadjusted number
is compared to the already adjusted one.

Based on report by YU, Haitao <yuhaitao@tsinghua.org.cn>

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

The option is named CONFIG_NF_NAT not CONFIG_IP_NF_NAT. Remove the ifdef
completely since helpers also expect defragmented packet even without
NAT.

Noticed by Robert P. J. Day <rpjday@mindspring.com>

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

iptables matches and targets expect packets to have at least a full
IP header and a valid header length. Ignore packets sent through
raw sockets for which this isn't true as in the other tables.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

nf_nat_rule_find, alloc_null_binding and alloc_null_binding_confirmed
do not use the argument 'info', which is actually ct->nat.info.
If they are necessary to access it again, we can use the argument 'ct'
instead.

Signed-off-by: Yasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

- move arp_tables initial table structure definitions to arp_tables.h
  similar to ip_tables and ip6_tables

- use C99 initializers

- use initializer macros where possible

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

I needed to use this recently to talk to a Cisco server.  In my case
I only did SNAT while the Cisco server used a different address for
RTP traffic than the one for SIP.  I discovered that nf_nat_sip NATed
the RTP address to the SIP one which was unnecessary but OK.  However,
in doing so it did not DNAT the destination address on the RTP traffic
to the Cisco back to the original RTP address.

This patch corrects this by noting down the RTP address and using it
when the expectation fires.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>