GC is expected to happen asynchrously to the netlink interface. In the
netlink path, both insertion and removal of elements consist of two
steps, insertion followed by activation or deactivation followed by
removal, during which the element must not be freed by GC.
The synchronization helpers use an unused bit in the genmask field to
atomically mark an element as "busy", meaning it is either currently
being handled through the netlink API or by GC.
Elements being processed by GC will never survive, netlink will simply
ignore them. Elements being currently processed through netlink will be
skipped by GC and reprocessed during the next run.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Add helpers for GC batch destruction: since element destruction needs
a RCU grace period for all set implementations, add some helper functions
for asynchronous batch destruction. Elements are collected in a batch
structure, which is asynchronously released using RCU once its full.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Add API support for set element timeouts. Elements can have a individual
timeout value specified, overriding the sets' default.
Two new extension types are used for timeouts - the timeout value and
the expiration time. The timeout value only exists if it differs from
the default value.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Add set timeout support to the netlink API. Sets with timeout support
enabled can have a default timeout value and garbage collection interval
specified.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Set elements are the last object type not supporting transaction support.
Implement similar to the existing rule transactions:
The global transaction counter keeps track of two generations, current
and next. Each element contains a bitmask specifying in which generations
it is inactive.
New elements start out as inactive in the current generation and active
in the next. On commit, the previous next generation becomes the current
generation and the element becomes active. The bitmask is then cleared
to indicate that the element is active in all future generations. If the
transaction is aborted, the element is removed from the set before it
becomes active.
When removing an element, it gets marked as inactive in the next generation.
On commit the next generation becomes active and the therefor the element
inactive. It is then taken out of then set and released. On abort, the
element is marked as active for the next generation again.
Lookups ignore elements not active in the current generation.
The current set types (hash/rbtree) both use a field in the extension area
to store the generation mask. This (currently) does not require any
additional memory since we have some free space in there.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Add some helper functions for building the genmask as preparation for
set transactions.
Also add a little documentation how this stuff actually works.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
With the conversion to set extensions, it is now possible to consolidate
the different set element destruction functions.
The set implementations' ->remove() functions are changed to only take
the element out of their internal data structures. Elements will be freed
in a batched fashion after the global transaction's completion RCU grace
period.
This reduces the amount of grace periods required for nft_hash from N
to zero additional ones, additionally this guarantees that the set
elements' extensions of all implementations can be used under RCU
protection.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The set implementations' private struct will only contain the elements
needed to maintain the search structure, all other elements are moved
to the set extensions.
Element allocation and initialization is performed centrally by
nf_tables_api instead of by the different set implementations'
->insert() functions. A new "elemsize" member in the set ops specifies
the amount of memory to reserve for internal usage. Destruction
will also be moved out of the set implementations by a following patch.
Except for element allocation, the patch is a simple conversion to
using data from the extension area.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Add simple set extension infrastructure for maintaining variable sized
and optional per element data.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The network namespace is only needed for base chains to get at the
gencursor. Also convert to possible_net_t.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Conflicts:
net/netfilter/nf_tables_core.c
The nf_tables_core.c conflict was resolved using a conflict resolution
from Stephen Rothwell as a guide.
Signed-off-by: David S. Miller <davem@davemloft.net>
If there's an existing base chain, we have to allow to change the
default policy without indicating the hook information.
However, if the chain doesn't exists, we have to enforce the presence of
the hook attribute.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Conflicts:
drivers/net/ethernet/cadence/macb.c
Overlapping changes in macb driver, mostly fixes and cleanups
in 'net' overlapping with the integration of at91_ether into
macb in 'net-next'.
Signed-off-by: David S. Miller <davem@davemloft.net>
In general, if a transaction object is added to the list successfully,
we can rely on the abort path to undo what we've done. This allows us to
simplify the error handling of the rule replacement path in
nf_tables_newrule().
This implicitly fixes an unnecessary removal of the old rule, which
needs to be left in place if we fail to replace.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The NFT_USERDATA_MAXLEN is defined to 256, however we only have a u8
to store its size. Introduce a struct nft_userdata which contains a
length field and indicate its presence using a single bit in the rule.
The length field of struct nft_userdata is also a u8, however we don't
store zero sized data, so the actual length is udata->len + 1.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Check that the space required for the expressions doesn't exceed the
size of the dlen field, which would lead to the iterators crashing.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
A race condition exists in the rule transaction code for rules that
get added and removed within the same transaction.
The new rule starts out as inactive in the current and active in the
next generation and is inserted into the ruleset. When it is deleted,
it is additionally set to inactive in the next generation as well.
On commit the next generation is begun, then the actions are finalized.
For the new rule this would mean clearing out the inactive bit for
the previously current, now next generation.
However nft_rule_clear() clears out the bits for *both* generations,
activating the rule in the current generation, where it should be
deactivated due to being deleted. The rule will thus be active until
the deletion is finalized, removing the rule from the ruleset.
Similarly, when aborting a transaction for the same case, the undo
of insertion will remove it from the RCU protected rule list, the
deletion will clear out all bits. However until the next RCU
synchronization after all operations have been undone, the rule is
active on CPUs which can still see the rule on the list.
Generally, there may never be any modifications of the current
generations' inactive bit since this defeats the entire purpose of
atomicity. Change nft_rule_clear() to only touch the next generations
bit to fix this.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
We have several problems in this path:
1) There is a use-after-free when removing individual elements from
the commit path.
2) We have to uninit() the data part of the element from the abort
path to avoid a chain refcount leak.
3) We have to check for set->flags to see if there's a mapping, instead
of the element flags.
4) We have to check for !(flags & NFT_SET_ELEM_INTERVAL_END) to skip
elements that are part of the interval that have no data part, so
they don't need to be uninit().
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Conflicts:
drivers/net/vxlan.c
drivers/vhost/net.c
include/linux/if_vlan.h
net/core/dev.c
The net/core/dev.c conflict was the overlap of one commit marking an
existing function static whilst another was adding a new function.
In the include/linux/if_vlan.h case, the type used for a local
variable was changed in 'net', whereas the function got rewritten
to fix a stacked vlan bug in 'net-next'.
In drivers/vhost/net.c, Al Viro's iov_iter conversions in 'net-next'
overlapped with an endainness fix for VHOST 1.0 in 'net'.
In drivers/net/vxlan.c, vxlan_find_vni() added a 'flags' parameter
in 'net-next' whereas in 'net' there was a bug fix to pass in the
correct network namespace pointer in calls to this function.
Signed-off-by: David S. Miller <davem@davemloft.net>
The user can crash the kernel if it uses any of the existing NAT
expressions from the wrong hook, so add some code to validate this
when loading the rule.
This patch introduces nft_chain_validate_hooks() which is based on
an existing function in the bridge version of the reject expression.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Contrary to common expectations for an "int" return, these functions
return only a positive value -- if used correctly they cannot even
return 0 because the message header will necessarily be in the skb.
This makes the very common pattern of
if (genlmsg_end(...) < 0) { ... }
be a whole bunch of dead code. Many places also simply do
return nlmsg_end(...);
and the caller is expected to deal with it.
This also commonly (at least for me) causes errors, because it is very
common to write
if (my_function(...))
/* error condition */
and if my_function() does "return nlmsg_end()" this is of course wrong.
Additionally, there's not a single place in the kernel that actually
needs the message length returned, and if anyone needs it later then
it'll be very easy to just use skb->len there.
Remove this, and make the functions void. This removes a bunch of dead
code as described above. The patch adds lines because I did
- return nlmsg_end(...);
+ nlmsg_end(...);
+ return 0;
I could have preserved all the function's return values by returning
skb->len, but instead I've audited all the places calling the affected
functions and found that none cared. A few places actually compared
the return value with <= 0 in dump functionality, but that could just
be changed to < 0 with no change in behaviour, so I opted for the more
efficient version.
One instance of the error I've made numerous times now is also present
in net/phonet/pn_netlink.c in the route_dumpit() function - it didn't
check for <0 or <=0 and thus broke out of the loop every single time.
I've preserved this since it will (I think) have caused the messages to
userspace to be formatted differently with just a single message for
every SKB returned to userspace. It's possible that this isn't needed
for the tools that actually use this, but I don't even know what they
are so couldn't test that changing this behaviour would be acceptable.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pablo Neira Ayuso says:
====================
netfilter/ipvs updates for net-next
The following patchset contains Netfilter updates for your net-next
tree, this includes the NAT redirection support for nf_tables, the
cgroup support for nft meta and conntrack zone support for the connlimit
match. Coming after those, a bunch of sparse warning fixes, missing
netns bits and cleanups. More specifically, they are:
1) Prepare IPv4 and IPv6 NAT redirect code to use it from nf_tables,
patches from Arturo Borrero.
2) Introduce the nf_tables redir expression, from Arturo Borrero.
3) Remove an unnecessary assignment in ip_vs_xmit/__ip_vs_get_out_rt().
Patch from Alex Gartrell.
4) Add nft_log_dereference() macro to the nf_log infrastructure, patch
from Marcelo Leitner.
5) Add some extra validation when registering logger families, also
from Marcelo.
6) Some spelling cleanups from stephen hemminger.
7) Fix sparse warning in nf_logger_find_get().
8) Add cgroup support to nf_tables meta, patch from Ana Rey.
9) A Kconfig fix for the new redir expression and fix sparse warnings in
the new redir expression.
10) Fix several sparse warnings in the netfilter tree, from
Florian Westphal.
11) Reduce verbosity when OOM in nfnetlink_log. User can basically do
nothing when this situation occurs.
12) Add conntrack zone support to xt_connlimit, again from Florian.
13) Add netnamespace support to the h323 conntrack helper, contributed
by Vasily Averin.
14) Remove unnecessary nul-pointer checks before free_percpu() and
module_put(), from Markus Elfring.
15) Use pr_fmt in nfnetlink_log, again patch from Marcelo Leitner.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
The functions free_percpu() and module_put() test whether their argument
is NULL and then return immediately. Thus the test around the call is
not needed.
This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Acked-by: Julian Anastasov <ja@ssi.bg>
Acked-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The existing xtables matches and targets, when used from nft_compat, may
sleep from the destroy path, ie. when removing rules. Since the objects
are released via call_rcu from softirq context, this results in lockdep
splats and possible lockups that may be hard to reproduce.
Patrick also indicated that delayed object release via call_rcu can
cause us problems in the ordering of event notifications when anonymous
sets are in place.
So, this patch restores the synchronous object release from the commit
and abort paths. This includes a call to synchronize_rcu() to make sure
that no packets are walking on the objects that are going to be
released. This is slowier though, but it's simple and it resolves the
aforementioned problems.
This is a partial revert of c7c32e7 ("netfilter: nf_tables: defer all
object release via rcu") that was introduced in 3.16 to speed up
interaction with userspace.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This adds the missing validation code to avoid the use of nat/masq from
non-nat chains. The validation assumes two possible configuration
scenarios:
1) Use of nat from base chain that is not of nat type. Reject this
configuration from the nft_*_init() path of the expression.
2) Use of nat from non-base chain. In this case, we have to wait until
the non-base chain is referenced by at least one base chain via
jump/goto. This is resolved from the nft_*_validate() path which is
called from nf_tables_check_loops().
The user gets an -EOPNOTSUPP in both cases.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
We want to know in which cases the user explicitly sets the policy
options. In that case, we also want to dump back the info.
Signed-off-by: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This patch exposes the ruleset generation ID in three ways:
1) The new command NFT_MSG_GETGEN that exposes the 32-bits ruleset
generation ID. This ID is incremented in every commit and it
should be large enough to avoid wraparound problems.
2) The less significant 16-bits of the generation ID are exposed through
the nfgenmsg->res_id header field. This allows us to quickly catch
if the ruleset has change between two consecutive list dumps from
different object lists (in this specific case I think the risk of
wraparound is unlikely).
3) Userspace subscribers may receive notifications of new rule-set
generation after every commit. This also provides an alternative
way to monitor the generation ID. If the events are lost, the
userspace process hits a overrun error, so it knows that it is
working with a stale ruleset anyway.
Patrick spotted that rule-set transformations in userspace may take
quite some time. In that case, it annotates the 32-bits generation ID
before fetching the rule-set, then:
1) it compares it to what we obtain after the transformation to
make sure it is not working with a stale rule-set and no wraparound
has ocurred.
2) it subscribes to ruleset notifications, so it can watch for new
generation ID.
This is complementary to the NLM_F_DUMP_INTR approach, which allows
us to detect an interference in the middle one single list dumping.
There is no way to explicitly check that an interference has occurred
between two list dumps from the kernel, since it doesn't know how
many lists the userspace client is actually going to dump.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This patch extend the NFT_MSG_DELTABLE call to support flushing the entire
ruleset.
The options now are:
* No family speficied, no table specified: flush all the ruleset.
* Family specified, no table specified: flush all tables in the AF.
* Family specified, table specified: flush the given table.
Signed-off-by: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This patch refactor the code to schedule objects deletion.
They are useful in follow-up patches.
In order to be able to use these new helper functions in all the code,
they are placed in the top of the file, with all the dependant functions
and symbols.
nft_rule_disactivate_next has been renamed to nft_rule_deactivate.
Signed-off-by: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
For the sake of homogenize the function naming scheme, let's rename
nf_table_delrule_by_chain() to nft_delrule_by_chain().
Signed-off-by: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This patch adds a helper function to unregister chain hooks in the chain
deletion path. Basically, a code factorization.
The new function is useful in follow-up patches.
Signed-off-by: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This helper function always schedule the rule to be removed in the following
transaction.
In follow-up patches, it is interesting to handle separately the logic of rule
activation/disactivation from the transaction mechanism.
So, this patch simply splits the original nf_tables_delrule_one() in two
functions, allowing further control.
While at it, for the sake of homigeneize the function naming scheme, let's
rename nf_tables_delrule_one() to nft_delrule().
Signed-off-by: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Convert a zero return value on error to a negative one, as returned
elsewhere in the function.
A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)
// <smpl>
@@
identifier ret; expression e1,e2;
@@
(
if (\(ret < 0\|ret != 0\))
{ ... return ret; }
|
ret = 0
)
... when != ret = e1
when != &ret
*if(...)
{
... when != ret = e2
when forall
return ret;
}
// </smpl>
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Fix possible replacement of the per-cpu chain counters by null
pointer when updating an existing chain in the commit path.
Reported-by: Matteo Croce <technoboy85@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This should happen once the element has been effectively released in
the commit path, not before. This fixes a possible chain refcount leak
if the transaction is aborted.
Reported-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Conflicts:
drivers/net/Makefile
net/ipv6/sysctl_net_ipv6.c
Two ipv6_table_template[] additions overlap, so the index
of the ipv6_table[x] assignments needed to be adjusted.
In the drivers/net/Makefile case, we've gotten rid of the
garbage whereby we had to list every single USB networking
driver in the top-level Makefile, there is just one
"USB_NETWORKING" that guards everything.
Signed-off-by: David S. Miller <davem@davemloft.net>
nft_del_setelem() currently calls nft_data_uninit() twice on the same
key. Once to release the key which is guaranteed to be NFT_DATA_VALUE
and a second time in the error path to which it falls through.
The second call has been harmless so far though because the type
passed is always NFT_DATA_VALUE which is currently a no-op.
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Otherwise, the kernel oopses in nla_for_each_nested when iterating over
the unset attribute NFTA_SET_ELEM_LIST_ELEMENTS in the
nf_tables_{new,del}setelem() path.
netlink: 65524 bytes leftover after parsing attributes in process `nft'.
[...]
Oops: 0000 [#1] SMP
[...]
CPU: 2 PID: 6287 Comm: nft Not tainted 3.16.0-rc2+ #169
RIP: 0010:[<ffffffffa0526e61>] [<ffffffffa0526e61>] nf_tables_newsetelem+0x82/0xec [nf_tables]
[...]
Call Trace:
[<ffffffffa05178c4>] nfnetlink_rcv+0x2e7/0x3d7 [nfnetlink]
[<ffffffffa0517939>] ? nfnetlink_rcv+0x35c/0x3d7 [nfnetlink]
[<ffffffff8137d300>] netlink_unicast+0xf8/0x17a
[<ffffffff8137d6a5>] netlink_sendmsg+0x323/0x351
[...]
Fix this by returning -EINVAL if this attribute is not set, which
doesn't make sense at all since those commands are there to add and to
delete elements from the set.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This patch uses the cb->data pointer that allows us to store the
context when dumping the set list. Thus, we don't need to parse the
original netlink message containing the dump request for each recvmsg()
call when dumping the set list. The different function flavours
depending on the dump criteria has been also merged into one single
generic function. This saves us ~100 lines of code.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Use generic u64_stats_sync infrastructure to get proper 64bit stats,
even on 32bit arches, at no extra cost for 64bit arches.
Without this fix, 32bit arches can have some wrong counters at the time
the carry is propagated into upper word.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
An updater may interfer with the dumping of any of the object lists.
Fix this by using a per-net generation counter and use the
nl_dump_check_consistent() interface so the NLM_F_DUMP_INTR flag is set
to notify userspace that it has to restart the dump since an updater
has interfered.
This patch also replaces the existing consistency checking code in the
rule dumping path since it is broken. Basically, the value that the
dump callback returns is not propagated to userspace via
netlink_dump_start().
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
