linux.git/net/netfilter/xt_CT.c, branch v4.20

netfilter: conntrack: remove l3->l4 mapping information

2018-09-20T16:07:35+00:00

l4 protocols are demuxed by l3num, l4num pair.

However, almost all l4 trackers are l3 agnostic.

Only exceptions are:
 - gre, icmp (ipv4 only)
 - icmpv6 (ipv6 only)

This commit gets rid of the l3 mapping, l4 trackers can now be looked up
by their IPPROTO_XXX value alone, which gets rid of the additional l3
indirection.

For icmp, ipcmp6 and gre, add a check on state->pf and
return -NF_ACCEPT in case we're asked to track e.g. icmpv6-in-ipv4,
this seems more fitting than using the generic tracker.

Additionally we can kill the 2nd l4proto definitions that were needed
for v4/v6 split -- they are now the same so we can use single l4proto
struct for each protocol, rather than two.

The EXPORT_SYMBOLs can be removed as all these object files are
part of nf_conntrack with no external references.

Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso

netfilter: cttimeout: decouple timeout policy from nfnetlink_cttimeout object

2018-08-07T15:14:15+00:00

The timeout policy is currently embedded into the nfnetlink_cttimeout
object, move the policy into an independent object. This allows us to
reuse part of the existing conntrack timeout extension from nf_tables
without adding dependencies with the nfnetlink_cttimeout object layout.

Signed-off-by: Pablo Neira Ayuso

netfilter: Remove useless param helper of nf_ct_helper_ext_add

2018-07-18T09:26:42+00:00

The param helper of nf_ct_helper_ext_add is useless now, then remove
it now.

Signed-off-by: Gao Feng 
Signed-off-by: Pablo Neira Ayuso

netfilter: xt_CT: Reject the non-null terminated string from user space

2018-06-01T08:14:51+00:00

The helper and timeout strings are from user-space, we need to make
sure they are null terminated. If not, evil user could make kernel
read the unexpected memory, even print it when fail to find by the
following codes.

pr_info_ratelimited("No such helper \"%s\"\n", helper_name);

Signed-off-by: Gao Feng 
Acked-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso

netfilter: xt_CT: use pr ratelimiting

2018-02-14T20:05:34+00:00

checkpatch complains about line > 80 but this would require splitting
"literal" over two lines which is worse.

Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso

netfilter: conntrack: make protocol tracker pointers const

2017-08-24T16:52:33+00:00

Doesn't change generated code, but will make it easier to eventually
make the actual trackers themselvers const.

Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso

netfilter: introduce nf_conntrack_helper_put helper function

2017-05-15T10:42:29+00:00

And convert module_put invocation to nf_conntrack_helper_put, this is
prepared for the followup patch, which will add a refcnt for cthelper,
so we can reject the deleting request when cthelper is in use.

Signed-off-by: Liping Zhang 
Signed-off-by: Pablo Neira Ayuso

Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf

2017-05-03T14:11:26+00:00

Pablo Neira Ayuso says:

====================
Netfilter/IPVS/OVS fixes for net

The following patchset contains a rather large batch of Netfilter, IPVS
and OVS fixes for your net tree. This includes fixes for ctnetlink, the
userspace conntrack helper infrastructure, conntrack OVS support,
ebtables DNAT target, several leaks in error path among other. More
specifically, they are:

1) Fix reference count leak in the CT target error path, from Gao Feng.

2) Remove conntrack entry clashing with a matching expectation, patch
   from Jarno Rajahalme.

3) Fix bogus EEXIST when registering two different userspace helpers,
   from Liping Zhang.

4) Don't leak dummy elements in the new bitmap set type in nf_tables,
   from Liping Zhang.

5) Get rid of module autoload from conntrack update path in ctnetlink,
   we don't need autoload at this late stage and it is happening with
   rcu read lock held which is not good. From Liping Zhang.

6) Fix deadlock due to double-acquire of the expect_lock from conntrack
   update path, this fixes a bug that was introduced when the central
   spinlock got removed. Again from Liping Zhang.

7) Safe ct->status update from ctnetlink path, from Liping. The expect_lock
   protection that was selected when the central spinlock was removed was
   not really protecting anything at all.

8) Protect sequence adjustment under ct->lock.

9) Missing socket match with IPv6, from Peter Tirsek.

10) Adjust skb->pkt_type of DNAT'ed frames from ebtables, from
    Linus Luessing.

11) Don't give up on evaluating the expression on new entries added via
    dynset expression in nf_tables, from Liping Zhang.

12) Use skb_checksum() when mangling icmpv6 in IPv6 NAT as this deals
    with non-linear skbuffs.

13) Don't allow IPv6 service in IPVS if no IPv6 support is available,
    from Paolo Abeni.

14) Missing mutex release in error path of xt_find_table_lock(), from
    Dan Carpenter.

15) Update maintainers files, Netfilter section. Add Florian to the
    file, refer to nftables.org and change project status from Supported
    to Maintained.

16) Bail out on mismatching extensions in element updates in nf_tables.
====================

Signed-off-by: David S. Miller

netfilter: xt_CT: fix refcnt leak on error path

2017-04-24T18:03:01+00:00

There are two cases which causes refcnt leak.

1. When nf_ct_timeout_ext_add failed in xt_ct_set_timeout, it should
free the timeout refcnt.
Now goto the err_put_timeout error handler instead of going ahead.

2. When the time policy is not found, we should call module_put.
Otherwise, the related cthelper module cannot be removed anymore.
It is easy to reproduce by typing the following command:
  # iptables -t raw -A OUTPUT -p tcp -j CT --helper ftp --timeout xxx

Signed-off-by: Gao Feng 
Signed-off-by: Liping Zhang 
Signed-off-by: Pablo Neira Ayuso

netfilter: kill the fake untracked conntrack objects

2017-04-15T09:47:57+00:00

resurrect an old patch from Pablo Neira to remove the untracked objects.

Currently, there are four possible states of an skb wrt. conntrack.

1. No conntrack attached, ct is NULL.
2. Normal (kmem cache allocated) ct attached.
3. a template (kmalloc'd), not in any hash tables at any point in time
4. the 'untracked' conntrack, a percpu nf_conn object, tagged via
   IPS_UNTRACKED_BIT in ct->status.

Untracked is supposed to be identical to case 1.  It exists only
so users can check

-m conntrack --ctstate UNTRACKED vs.
-m conntrack --ctstate INVALID

e.g. attempts to set connmark on INVALID or UNTRACKED conntracks is
supposed to be a no-op.

Thus currently we need to check
 ct == NULL || nf_ct_is_untracked(ct)

in a lot of places in order to avoid altering untracked objects.

The other consequence of the percpu untracked object is that all
-j NOTRACK (and, later, kfree_skb of such skbs) result in an atomic op
(inc/dec the untracked conntracks refcount).

This adds a new kernel-private ctinfo state, IP_CT_UNTRACKED, to
make the distinction instead.

The (few) places that care about packet invalid (ct is NULL) vs.
packet untracked now need to test ct == NULL vs. ctinfo == IP_CT_UNTRACKED,
but all other places can omit the nf_ct_is_untracked() check.

Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso