Pablo Neira Ayuso says:
====================
This small batch contains several Netfilter fixes for your net-next
tree, more specifically:
* Fix compilation warning in nft_ct in NF_CONNTRACK_MARK is not set,
from Kristian Evensen.
* Add dependency to IPV6 for NF_TABLES_INET. This one has been reported
by the several robots that are testing .config combinations, from Paul
Gortmaker.
* Fix default base chain policy setting in nf_tables, from myself.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
net/netfilter/nft_ct.c: In function 'nft_ct_set_eval':
net/netfilter/nft_ct.c:136:6: warning: unused variable 'value' [-Wunused-variable]
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Kristian Evensen <kristian.evensen@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This patch removes the net_random and net_srandom macros and replaces
them with direct calls to the prandom ones. As new commits only seem to
use prandom_u32 there is no use to keep them around.
This change makes it easier to grep for users of prandom_u32.
Signed-off-by: Aruna-Hewapathirane <aruna.hewapathirane@gmail.com>
Suggested-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit 1d49144c0a ("netfilter: nf_tables: add "inet" table for
IPv4/IPv6") allows creation of non-IPV6 enabled .config files that
will fail to configure/link as follows:
warning: (NF_TABLES_INET) selects NF_TABLES_IPV6 which has unmet direct dependencies (NET && INET && IPV6 && NETFILTER && NF_TABLES)
warning: (NF_TABLES_INET) selects NF_TABLES_IPV6 which has unmet direct dependencies (NET && INET && IPV6 && NETFILTER && NF_TABLES)
warning: (NF_TABLES_INET) selects NF_TABLES_IPV6 which has unmet direct dependencies (NET && INET && IPV6 && NETFILTER && NF_TABLES)
net/built-in.o: In function `nft_reject_eval':
nft_reject.c:(.text+0x651e8): undefined reference to `nf_ip6_checksum'
nft_reject.c:(.text+0x65270): undefined reference to `ip6_route_output'
nft_reject.c:(.text+0x656c4): undefined reference to `ip6_dst_hoplimit'
make: *** [vmlinux] Error 1
Since the feature is to allow for a mixed IPV4 and IPV6 table, it
seems sensible to make it depend on IPV6.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Acked-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Pablo Neira Ayuso says:
====================
This batch contains one single patch with the l2tp match
for xtables, from James Chapman.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
When fetching the policy attribute, the byteorder conversion was
missing, breaking the chain policy setting.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Pablo Neira Ayuso says:
====================
nf_tables updates for net-next
The following patchset contains the following nf_tables updates,
mostly updates from Patrick McHardy, they are:
* Add the "inet" table and filter chain type for this new netfilter
family: NFPROTO_INET. This special table/chain allows IPv4 and IPv6
rules, this should help to simplify the burden in the administration
of dual stack firewalls. This also includes several patches to prepare
the infrastructure for this new table and a new meta extension to
match the layer 3 and 4 protocol numbers, from Patrick McHardy.
* Load both IPv4 and IPv6 conntrack modules in nft_ct if the rule is used
in NFPROTO_INET, as we don't certainly know which one would be used,
also from Patrick McHardy.
* Do not allow to delete a table that contains sets, otherwise these
sets become orphan, from Patrick McHardy.
* Hold a reference to the corresponding nf_tables family module when
creating a table of that family type, to avoid the module deletion
when in use, from Patrick McHardy.
* Update chain counters before setting the chain policy to ensure that
we don't leave the chain in inconsistent state in case of errors (aka.
restore chain atomicity). This also fixes a possible leak if it fails
to allocate the chain counters if no counters are passed to be restored,
from Patrick McHardy.
* Don't check for overflows in the table counter if we are just renaming
a chain, from Patrick McHardy.
* Replay the netlink request after dropping the nfnl lock to load the
module that supports provides a chain type, from Patrick.
* Fix chain type module references, from Patrick.
* Several cleanups, function renames, constification and code
refactorizations also from Patrick McHardy.
* Add support to set the connmark, this can be used to set it based on
the meta mark (similar feature to -j CONNMARK --restore), from
Kristian Evensen.
* A couple of fixes to the recently added meta/set support and nft_reject,
and fix missing chain type unregistration if we fail to register our
the family table/filter chain type, from myself.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Introduce an xtables add-on for matching L2TP packets. Supports L2TPv2
and L2TPv3 over IPv4 and IPv6. As well as filtering on L2TP tunnel-id
and session-id, the filtering decision can also include the L2TP
packet type (control or data), protocol version (2 or 3) and
encapsulation type (UDP or IP).
The most common use for this will likely be to filter L2TP data
packets of individual L2TP tunnels or sessions. While a u32 match can
be used, the L2TP protocol headers are such that field offsets differ
depending on bits set in the header, making rules for matching generic
L2TP connections cumbersome. This match extension takes care of all
that.
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
We don't encode argument types into function names and since besides
nft_do_chain() there are only AF-specific versions, there is no risk
of confusion.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
We currently leak the set memory when deleting a table that still has
sets in it. Return EBUSY when attempting to delete a table with sets.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The table refers to data of the AF module, so we need to make sure the
module isn't unloaded while the table exists.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Simplifies error handling. Additionally use the correct type u32 for the
host byte order flags value.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Minor nf_chain_type cleanups:
- reorder struct to plug a hoe
- rename struct module member to "owner" for consistency
- rename nf_hookfn array to "hooks" for consistency
- reorder initializers for better readability
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
To avoid races, we need to replay to request after dropping the nfnl_mutex
to auto-load the chain type module.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
In some cases we neither take a reference to the AF info nor to the
chain type, allowing the module to be unloaded while in use.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The chain type module reference handling makes no sense at all: we take
a reference immediately when the module is registered, preventing the
module from ever being unloaded.
Fix by taking a reference when we're actually creating a chain of the
chain type and release the reference when destroying the chain.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The table use counter is only increased for new chains, so move the check
to the correct position.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Chain counter validation is performed after the chain policy has
potentially been changed. Move counter validation/setting before
changing of the chain policy to fix this.
Additionally fix a memory leak if chain counter allocation fails
for new chains, remove an unnecessary free_percpu() and move
counter allocation for new chains
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Currently nf_tables_newchain() atomicity is broken because of having
validation of some netlink attributes performed after changing attributes
of the chain. The chain policy is (currently) fine, but split it up as
preparation for the following fixes and to avoid future mistakes.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
We have to validate that the input register is in the range of
allowed registers, otherwise we can take a incorrect register
value as input that may lead us to a crash.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This patch adds kernel support for setting properties of tracked
connections. Currently, only connmark is supported. One use-case
for this feature is to provide the same functionality as
-j CONNMARK --save-mark in iptables.
Some restructuring was needed to implement the set op. The new
structure follows that of nft_meta.
Signed-off-by: Kristian Evensen <kristian.evensen@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Pablo Neira Ayuso says:
====================
Netfilter updates for net-next
The following patchset contains three Netfilter updates, they are:
* Fix wrong usage of skb_header_pointer in the DCCP protocol helper that
has been there for quite some time. It was resulting in copying the dccp
header to a pointer allocated in the stack. Fortunately, this pointer
provides room for the dccp header is 4 bytes long, so no crashes have been
reported so far. From Daniel Borkmann.
* Use format string to print in the invocation of nf_log_packet(), again
in the DCCP helper. Also from Daniel Borkmann.
* Revert "netfilter: avoid get_random_bytes call" as prandom32 does not
guarantee enough entropy when being calling this at boot time, that may
happen when reloading the rule.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
The ct expression can currently not be used in the inet family since
we don't have a conntrack module for NFPROTO_INET, so
nf_ct_l3proto_try_module_get() fails. Add some manual handling to
load the modules for both NFPROTO_IPV4 and NFPROTO_IPV6 if the
ct expression is used in the inet family.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
For L3-proto independant rules we need to get at the L4 protocol value
directly. Add it to the nft_pktinfo struct and use the meta expression
to retrieve it.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Needed by multi-family tables to distinguish IPv4 and IPv6 packets.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This patch adds a new table family and a new filter chain that you can
use to attach IPv4 and IPv6 rules. This should help to simplify
rule-set maintainance in dual-stack setups.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Add support to register chains to multiple hooks for different address
families for mixed IPv4/IPv6 tables.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Multi-family tables need the AF from the hook ops. Add a pointer to the
hook ops and replace usage of the hooknum member in struct nft_pktinfo.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Currently the AF-specific hook functions override the chain-type specific
hook functions. That doesn't make too much sense since the chain types
are a special case of the AF-specific hooks.
Make the AF-specific hook functions the default and make the optional
chain type hooks override them.
As a side effect, the necessary code restructuring reduces the code size,
f.i. in case of nf_tables_ipv4.o:
nf_tables_ipv4_init_net | -24
nft_do_chain_ipv4 | -113
2 functions changed, 137 bytes removed, diff: -137
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
net/netfilter/nft_reject.c: In function 'nft_reject_eval':
net/netfilter/nft_reject.c:37:14: warning: unused variable 'net' [-Wunused-variable]
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Jesse Gross says:
====================
[GIT net-next] Open vSwitch
Open vSwitch changes for net-next/3.14. Highlights are:
* Performance improvements in the mechanism to get packets to userspace
using memory mapped netlink and skb zero copy where appropriate.
* Per-cpu flow stats in situations where flows are likely to be shared
across CPUs. Standard flow stats are used in other situations to save
memory and allocation time.
* A handful of code cleanups and rationalization.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Make the skb zerocopy logic written for nfnetlink queue available for
use by other modules.
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Reviewed-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jesse Gross <jesse@nicira.com>
Conflicts:
drivers/net/ethernet/qlogic/qlcnic/qlcnic_sriov_pf.c
net/ipv6/ip6_tunnel.c
net/ipv6/ip6_vti.c
ipv6 tunnel statistic bug fixes conflicting with consolidation into
generic sw per-cpu net stats.
qlogic conflict between queue counting bug fix and the addition
of multiple MAC address support.
Signed-off-by: David S. Miller <davem@davemloft.net>
net/netfilter/nfnetlink_queue_core.c: In function 'nfqnl_put_sk_uidgid':
net/netfilter/nfnetlink_queue_core.c:304:35: error: 'TCP_TIME_WAIT' undeclared (first use in this function)
net/netfilter/nfnetlink_queue_core.c:304:35: note: each undeclared identifier is reported only once for each function it appears in
make[3]: *** [net/netfilter/nfnetlink_queue_core.o] Error 1
Just a missing include of net/tcp_states.h
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pablo Neira Ayuso says: <pablo@netfilter.org>
====================
nftables updates for net-next
The following patchset contains nftables updates for your net-next tree,
they are:
* Add set operation to the meta expression by means of the select_ops()
infrastructure, this allows us to set the packet mark among other things.
From Arturo Borrero Gonzalez.
* Fix wrong format in sscanf in nf_tables_set_alloc_name(), from Daniel
Borkmann.
* Add new queue expression to nf_tables. These comes with two previous patches
to prepare this new feature, one to add mask in nf_tables_core to
evaluate the queue verdict appropriately and another to refactor common
code with xt_NFQUEUE, from Eric Leblond.
* Do not hide nftables from Kconfig if nfnetlink is not enabled, also from
Eric Leblond.
* Add the reject expression to nf_tables, this adds the missing TCP RST
support. It comes with an initial patch to refactor common code with
xt_NFQUEUE, again from Eric Leblond.
* Remove an unused variable assignment in nf_tables_dump_set(), from Michal
Nazarewicz.
* Remove the nft_meta_target code, now that Arturo added the set operation
to the meta expression, from me.
* Add help information for nf_tables to Kconfig, also from me.
* Allow to dump all sets by specifying NFPROTO_UNSPEC, similar feature is
available to other nf_tables objects, requested by Arturo, from me.
* Expose the table usage counter, so we can know how many chains are using
this table without dumping the list of chains, from Tomasz Bursztyka.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Some occurences in the netfilter tree use skb_header_pointer() in
the following way ...
struct dccp_hdr _dh, *dh;
...
skb_header_pointer(skb, dataoff, sizeof(_dh), &dh);
... where dh itself is a pointer that is being passed as the copy
buffer. Instead, we need to use &_dh as the forth argument so that
we're copying the data into an actual buffer that sits on the stack.
Currently, we probably could overwrite memory on the stack (e.g.
with a possibly mal-formed DCCP packet), but unintentionally, as
we only want the buffer to be placed into _dh variable.
Fixes: 2bc780499a ("[NETFILTER]: nf_conntrack: add DCCP protocol support")
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Avoid potentially spamming the kernel log with WARN splash messages
when catching wrong usage of seqadj, by simply using WARN_ONCE.
This is a followup to commit db12cf2743 (netfilter: WARN about
wrong usage of sequence number adjustments)
Suggested-by: Flavio Leitner <fbl@redhat.com>
Suggested-by: Daniel Borkmann <dborkman@redhat.com>
Suggested-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Some invocations of nf_log_packet() use arg buffer directly instead of
"%s" format string with follow-up buffer pointer. Currently, these two
usages are not really critical, but we should fix this up nevertheless
so that we don't run into trouble if that changes one day.
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Commit 5901b6be88 attempted to introduce IPv6 support into
IRC NAT helper. By doing so, the following code seemed to be removed
by accident:
ip = ntohl(exp->master->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3.ip);
sprintf(buffer, "%u %u", ip, port);
pr_debug("nf_nat_irc: inserting '%s' == %pI4, port %u\n", buffer, &ip, port);
This leads to the fact that buffer[] was left uninitialized and
contained some stack value. When we call nf_nat_mangle_tcp_packet(),
we call strlen(buffer) on excatly this uninitialized buffer. If we
are unlucky and the skb has enough tailroom, we overwrite resp. leak
contents with values that sit on our stack into the packet and send
that out to the receiver.
Since the rather informal DCC spec [1] does not seem to specify
IPv6 support right now, we log such occurences so that admins can
act accordingly, and drop the packet. I've looked into XChat source,
and IPv6 is not supported there: addresses are in u32 and print
via %u format string.
Therefore, restore old behaviour as in IPv4, use snprintf(). The
IRC helper does not support IPv6 by now. By this, we can safely use
strlen(buffer) in nf_nat_mangle_tcp_packet() and prevent a buffer
overflow. Also simplify some code as we now have ct variable anyway.
[1] http://www.irchelp.org/irchelp/rfc/ctcpspec.html
Fixes: 5901b6be88 ("netfilter: nf_nat: support IPv6 in IRC NAT helper")
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Cc: Harald Welte <laforge@gnumonks.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This reverts commit a42b99a6e3.
Hannes Frederic Sowa reported some problems with this patch, more specifically
that prandom_u32() may not be ready at boot time, see:
http://marc.info/?l=linux-netdev&m=138896532403533&w=2
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Pablo Neira Ayuso says:
====================
netfilter/IPVS updates for net-next
The following patchset contains Netfilter updates for your net-next tree,
they are:
* Add full port randomization support. Some crazy researchers found a way
to reconstruct the secure ephemeral ports that are allocated in random mode
by sending off-path bursts of UDP packets to overrun the socket buffer of
the DNS resolver to trigger retransmissions, then if the timing for the
DNS resolution done by a client is larger than usual, then they conclude
that the port that received the burst of UDP packets is the one that was
opened. It seems a bit aggressive method to me but it seems to work for
them. As a result, Daniel Borkmann and Hannes Frederic Sowa came up with a
new NAT mode to fully randomize ports using prandom.
* Add a new classifier to x_tables based on the socket net_cls set via
cgroups. These includes two patches to prepare the field as requested by
Zefan Li. Also from Daniel Borkmann.
* Use prandom instead of get_random_bytes in several locations of the
netfilter code, from Florian Westphal.
* Allow to use the CTA_MARK_MASK in ctnetlink when mangling the conntrack
mark, also from Florian Westphal.
* Fix compilation warning due to unused variable in IPVS, from Geert
Uytterhoeven.
* Add support for UID/GID via nfnetlink_queue, from Valentina Giusti.
* Add IPComp extension to x_tables, from Fan Du.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch allows you to dump all sets available in all of
the registered families. This allows you to use NFPROTO_UNSPEC
to dump all existing sets, similarly to other existing table,
chain and rule operations.
This patch is based on original patch from Arturo Borrero
González.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
It would be useful e.g. in a server or desktop environment to have
a facility in the notion of fine-grained "per application" or "per
application group" firewall policies. Probably, users in the mobile,
embedded area (e.g. Android based) with different security policy
requirements for application groups could have great benefit from
that as well. For example, with a little bit of configuration effort,
an admin could whitelist well-known applications, and thus block
otherwise unwanted "hard-to-track" applications like [1] from a
user's machine. Blocking is just one example, but it is not limited
to that, meaning we can have much different scenarios/policies that
netfilter allows us than just blocking, e.g. fine grained settings
where applications are allowed to connect/send traffic to, application
traffic marking/conntracking, application-specific packet mangling,
and so on.
Implementation of PID-based matching would not be appropriate
as they frequently change, and child tracking would make that
even more complex and ugly. Cgroups would be a perfect candidate
for accomplishing that as they associate a set of tasks with a
set of parameters for one or more subsystems, in our case the
netfilter subsystem, which, of course, can be combined with other
cgroup subsystems into something more complex if needed.
As mentioned, to overcome this constraint, such processes could
be placed into one or multiple cgroups where different fine-grained
rules can be defined depending on the application scenario, while
e.g. everything else that is not part of that could be dropped (or
vice versa), thus making life harder for unwanted processes to
communicate to the outside world. So, we make use of cgroups here
to track jobs and limit their resources in terms of iptables
policies; in other words, limiting, tracking, etc what they are
allowed to communicate.
In our case we're working on outgoing traffic based on which local
socket that originated from. Also, one doesn't even need to have
an a-prio knowledge of the application internals regarding their
particular use of ports or protocols. Matching is *extremly*
lightweight as we just test for the sk_classid marker of sockets,
originating from net_cls. net_cls and netfilter do not contradict
each other; in fact, each construct can live as standalone or they
can be used in combination with each other, which is perfectly fine,
plus it serves Tejun's requirement to not introduce a new cgroups
subsystem. Through this, we result in a very minimal and efficient
module, and don't add anything except netfilter code.
One possible, minimal usage example (many other iptables options
can be applied obviously):
1) Configuring cgroups if not already done, e.g.:
mkdir /sys/fs/cgroup/net_cls
mount -t cgroup -o net_cls net_cls /sys/fs/cgroup/net_cls
mkdir /sys/fs/cgroup/net_cls/0
echo 1 > /sys/fs/cgroup/net_cls/0/net_cls.classid
(resp. a real flow handle id for tc)
2) Configuring netfilter (iptables-nftables), e.g.:
iptables -A OUTPUT -m cgroup ! --cgroup 1 -j DROP
3) Running applications, e.g.:
ping 208.67.222.222 <pid:1799>
echo 1799 > /sys/fs/cgroup/net_cls/0/tasks
64 bytes from 208.67.222.222: icmp_seq=44 ttl=49 time=11.9 ms
[...]
ping 208.67.220.220 <pid:1804>
ping: sendmsg: Operation not permitted
[...]
echo 1804 > /sys/fs/cgroup/net_cls/0/tasks
64 bytes from 208.67.220.220: icmp_seq=89 ttl=56 time=19.0 ms
[...]
Of course, real-world deployments would make use of cgroups user
space toolsuite, or own custom policy daemons dynamically moving
applications from/to various cgroups.
[1] http://www.blackhat.com/presentations/bh-europe-06/bh-eu-06-biondi/bh-eu-06-biondi-up.pdf
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: cgroups@vger.kernel.org
Acked-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
If setting event mask fails then we were returning 0 for success.
This patch updates return code to -EINVAL in case of problem.
Signed-off-by: Eric Leblond <eric@regit.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The following code is not used in current upstream code.
Some of this seems to be old hooks, other might be used by some
out of tree module (which I don't care about breaking), and
the need_ipv4_conntrack was used by old NAT code but no longer
called.
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Function never used in current upstream code.
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
We currently use prandom_u32() for allocation of ports in tcp bind(0)
and udp code. In case of plain SNAT we try to keep the ports as is
or increment on collision.
SNAT --random mode does use per-destination incrementing port
allocation. As a recent paper pointed out in [1] that this mode of
port allocation makes it possible to an attacker to find the randomly
allocated ports through a timing side-channel in a socket overloading
attack conducted through an off-path attacker.
So, NF_NAT_RANGE_PROTO_RANDOM actually weakens the port randomization
in regard to the attack described in this paper. As we need to keep
compatibility, add another flag called NF_NAT_RANGE_PROTO_RANDOM_FULLY
that would replace the NF_NAT_RANGE_PROTO_RANDOM hash-based port
selection algorithm with a simple prandom_u32() in order to mitigate
this attack vector. Note that the lfsr113's internal state is
periodically reseeded by the kernel through a local secure entropy
source.
More details can be found in [1], the basic idea is to send bursts
of packets to a socket to overflow its receive queue and measure
the latency to detect a possible retransmit when the port is found.
Because of increasing ports to given destination and port, further
allocations can be predicted. This information could then be used by
an attacker for e.g. for cache-poisoning, NS pinning, and degradation
of service attacks against DNS servers [1]:
The best defense against the poisoning attacks is to properly
deploy and validate DNSSEC; DNSSEC provides security not only
against off-path attacker but even against MitM attacker. We hope
that our results will help motivate administrators to adopt DNSSEC.
However, full DNSSEC deployment make take significant time, and
until that happens, we recommend short-term, non-cryptographic
defenses. We recommend to support full port randomisation,
according to practices recommended in [2], and to avoid
per-destination sequential port allocation, which we show may be
vulnerable to derandomisation attacks.
Joint work between Hannes Frederic Sowa and Daniel Borkmann.
[1] https://sites.google.com/site/hayashulman/files/NIC-derandomisation.pdf
[2] http://arxiv.org/pdf/1205.5190v1.pdf
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
