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Supporting a 1:n relationship between nft_hook and nf_hook_ops is
convenient since a chain's or flowtable's nft_hooks may remain in place
despite matching interfaces disappearing. This stabilizes ruleset dumps
in that regard and opens the possibility to claim newly added interfaces
which match the spec. Also it prepares for wildcard interface specs
since these will potentially match multiple interfaces.
All spots dealing with hook registration are updated to handle a list of
multiple nf_hook_ops, but nft_netdev_hook_alloc() only adds a single
item for now to retain the old behaviour. The only expected functional
change here is how vanishing interfaces are handled: Instead of dropping
the respective nft_hook, only the matching nf_hook_ops are dropped.
To safely remove individual ops from the list in netdev handlers, an
rcu_head is added to struct nf_hook_ops so kfree_rcu() may be used.
There is at least nft_flowtable_find_dev() which may be iterating
through the list at the same time.
Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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While nf_conntrack_id() doesn't need any functionaliy from conntrack, it
does reside in nf_conntrack_core.c -- callers add a module
dependency on conntrack.
Followup patch will need to compute the conntrack id from nf_tables_trace.c
to include it in nf_trace messages emitted to userspace via netlink.
I don't want to introduce a module dependency between nf_tables and
conntrack for this.
Since trace is slowpath, the added indirection is ok.
One alternative is to move nf_conntrack_id to the netfilter/core.c,
but I don't see a compelling reason so far.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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nf_skb_duplicated is a per-CPU variable and relies on disabled BH for its
locking. Without per-CPU locking in local_bh_disable() on PREEMPT_RT
this data structure requires explicit locking.
Due to the recursion involved, the simplest change is to make it a
per-task variable.
Move the per-CPU variable nf_skb_duplicated to task_struct and name it
in_nf_duplicate. Add it to the existing bitfield so it doesn't use
additional memory.
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ben Segall <bsegall@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Valentin Schneider <vschneid@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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For historical reasons there are two clash resolution spots in
netfilter, one in nfnetlink_queue and one in conntrack core.
nfnetlink_queue one was added first: If a colliding entry is found, NAT
NAT transformation is reversed by calling nat engine again with altered
tuple.
See commit 368982cd7d1b ("netfilter: nfnetlink_queue: resolve clash for
unconfirmed conntracks") for details.
One problem is that nf_reroute() won't take an action if the queueing
doesn't occur in the OUTPUT hook, i.e. when queueing in forward or
postrouting, packet will be sent via the wrong path.
Another problem is that the scenario addressed (2nd UDP packet sent with
identical addresses while first packet is still being processed) can also
occur without any nfqueue involvement due to threaded resolvers doing
A and AAAA requests back-to-back.
This lead us to add clash resolution logic to the conntrack core, see
commit 6a757c07e51f ("netfilter: conntrack: allow insertion of clashing
entries"). Instead of fixing the nfqueue based logic, lets remove it
and let conntrack core handle this instead.
Retain the ->update hook for sake of nfqueue based conntrack helpers.
We could axe this hook completely but we'd have to split confirm and
helper logic again, see commit ee04805ff54a ("netfilter: conntrack: make
conntrack userspace helpers work again").
This SHOULD NOT be backported to kernels earlier than v5.6; they lack
adequate clash resolution handling.
Patch was originally written by Pablo Neira Ayuso.
Reported-by: Antonio Ojea <aojea@google.com>
Closes: https://bugzilla.netfilter.org/show_bug.cgi?id=1766
Signed-off-by: Florian Westphal <fw@strlen.de>
Tested-by: Antonio Ojea <aojea@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Cross-merge networking fixes after downstream PR.
Conflicts:
net/mptcp/protocol.c
adf1bb78dab5 ("mptcp: fix snd_wnd initialization for passive socket")
9426ce476a70 ("mptcp: annotate lockless access for RX path fields")
https://lore.kernel.org/all/20240228103048.19255709@canb.auug.org.au/
Adjacent changes:
drivers/dpll/dpll_core.c
0d60d8df6f49 ("dpll: rely on rcu for netdev_dpll_pin()")
e7f8df0e81bf ("dpll: move xa_erase() call in to match dpll_pin_alloc() error path order")
drivers/net/veth.c
1ce7d306ea63 ("veth: try harder when allocating queue memory")
0bef512012b1 ("net: add netdev_lockdep_set_classes() to virtual drivers")
drivers/net/wireless/intel/iwlwifi/mvm/d3.c
8c9bef26e98b ("wifi: iwlwifi: mvm: d3: implement suspend with MLO")
78f65fbf421a ("wifi: iwlwifi: mvm: ensure offloading TID queue exists")
net/wireless/nl80211.c
f78c1375339a ("wifi: nl80211: reject iftype change with mesh ID change")
414532d8aa89 ("wifi: cfg80211: use IEEE80211_MAX_MESH_ID_LEN appropriately")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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conntrack nf_confirm logic cannot handle cloned skbs referencing
the same nf_conn entry, which will happen for multicast (broadcast)
frames on bridges.
Example:
macvlan0
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br0
/ \
ethX ethY
ethX (or Y) receives a L2 multicast or broadcast packet containing
an IP packet, flow is not yet in conntrack table.
1. skb passes through bridge and fake-ip (br_netfilter)Prerouting.
-> skb->_nfct now references a unconfirmed entry
2. skb is broad/mcast packet. bridge now passes clones out on each bridge
interface.
3. skb gets passed up the stack.
4. In macvlan case, macvlan driver retains clone(s) of the mcast skb
and schedules a work queue to send them out on the lower devices.
The clone skb->_nfct is not a copy, it is the same entry as the
original skb. The macvlan rx handler then returns RX_HANDLER_PASS.
5. Normal conntrack hooks (in NF_INET_LOCAL_IN) confirm the orig skb.
The Macvlan broadcast worker and normal confirm path will race.
This race will not happen if step 2 already confirmed a clone. In that
case later steps perform skb_clone() with skb->_nfct already confirmed (in
hash table). This works fine.
But such confirmation won't happen when eb/ip/nftables rules dropped the
packets before they reached the nf_confirm step in postrouting.
Pablo points out that nf_conntrack_bridge doesn't allow use of stateful
nat, so we can safely discard the nf_conn entry and let inet call
conntrack again.
This doesn't work for bridge netfilter: skb could have a nat
transformation. Also bridge nf prevents re-invocation of inet prerouting
via 'sabotage_in' hook.
Work around this problem by explicit confirmation of the entry at LOCAL_IN
time, before upper layer has a chance to clone the unconfirmed entry.
The downside is that this disables NAT and conntrack helpers.
Alternative fix would be to add locking to all code parts that deal with
unconfirmed packets, but even if that could be done in a sane way this
opens up other problems, for example:
-m physdev --physdev-out eth0 -j SNAT --snat-to 1.2.3.4
-m physdev --physdev-out eth1 -j SNAT --snat-to 1.2.3.5
For multicast case, only one of such conflicting mappings will be
created, conntrack only handles 1:1 NAT mappings.
Users should set create a setup that explicitly marks such traffic
NOTRACK (conntrack bypass) to avoid this, but we cannot auto-bypass
them, ruleset might have accept rules for untracked traffic already,
so user-visible behaviour would change.
Suggested-by: Pablo Neira Ayuso <pablo@netfilter.org>
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217777
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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No need to keep this in the core, move it to the nfnetlink_queue module.
nf_reroute is moved too, there were no other callers.
Signed-off-by: Florian Westphal <fw@strlen.de>
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net_dropmonitor blames core.c:nf_hook_slow.
Add NF_DROP_REASON() helper and use it in nft_do_chain().
The helper releases the skb, so exact drop location becomes
available. Calling code will observe the NF_STOLEN verdict
instead.
Adjust nf_hook_slow so we can embed an erro value wih
NF_STOLEN verdicts, just like we do for NF_DROP.
After this, drop in nftables can be pinpointed to a drop due
to a rule or the chain policy.
Signed-off-by: Florian Westphal <fw@strlen.de>
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We want to be able to enable/disable IP packet defrag from core
bpf/netfilter code. In other words, execute code from core that could
possibly be built as a module.
To help avoid symbol resolution errors, use glue hooks that the modules
will register callbacks with during module init.
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Reviewed-by: Florian Westphal <fw@strlen.de>
Link: https://lore.kernel.org/r/f6a8824052441b72afe5285acedbd634bd3384c1.1689970773.git.dxu@dxuuu.xyz
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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kernel-doc does not support DECLARE_PER_CPU(), so don't mark it with
kernel-doc notation.
One comment block is not kernel-doc notation, so just use
"/*" to begin the comment.
Quietens these warnings:
netfilter.h:493: warning: Function parameter or member 'bool' not described in 'DECLARE_PER_CPU'
netfilter.h:493: warning: Function parameter or member 'nf_skb_duplicated' not described in 'DECLARE_PER_CPU'
netfilter.h:493: warning: expecting prototype for nf_skb_duplicated(). Prototype was for DECLARE_PER_CPU() instead
netfilter.h:496: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
* Contains bitmask of ctnetlink event subscribers, if any.
Fixes: e7c8899f3e6f ("netfilter: move tee_active to core")
Fixes: fdf6491193e4 ("netfilter: ctnetlink: make event listener tracking global")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Add bpf_link support skeleton. To keep this reviewable, no bpf program
can be invoked yet, if a program is attached only a c-stub is called and
not the actual bpf program.
Defaults to 'y' if both netfilter and bpf syscall are enabled in kconfig.
Uapi example usage:
union bpf_attr attr = { };
attr.link_create.prog_fd = progfd;
attr.link_create.attach_type = 0; /* unused */
attr.link_create.netfilter.pf = PF_INET;
attr.link_create.netfilter.hooknum = NF_INET_LOCAL_IN;
attr.link_create.netfilter.priority = -128;
err = bpf(BPF_LINK_CREATE, &attr, sizeof(attr));
... this would attach progfd to ipv4:input hook.
Such hook gets removed automatically if the calling program exits.
BPF_NETFILTER program invocation is added in followup change.
NF_HOOK_OP_BPF enum will eventually be read from nfnetlink_hook, it
allows to tell userspace which program is attached at the given hook
when user runs 'nft hook list' command rather than just the priority
and not-very-helpful 'this hook runs a bpf prog but I can't tell which
one'.
Will also be used to disallow registration of two bpf programs with
same priority in a followup patch.
v4: arm32 cmpxchg only supports 32bit operand
s/prio/priority/
v3: restrict prog attachment to ip/ip6 for now, lets lift restrictions if
more use cases pop up (arptables, ebtables, netdev ingress/egress etc).
Signed-off-by: Florian Westphal <fw@strlen.de>
Link: https://lore.kernel.org/r/20230421170300.24115-2-fw@strlen.de
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Pablo Neira Ayuso says:
====================
Netfilter fixes for net
1) Fix broken listing of set elements when table has an owner.
2) Fix conntrack refcount leak in ctnetlink with related conntrack
entries, from Hangyu Hua.
3) Fix use-after-free/double-free in ctnetlink conntrack insert path,
from Florian Westphal.
4) Fix ip6t_rpfilter with VRF, from Phil Sutter.
5) Fix use-after-free in ebtables reported by syzbot, also from Florian.
6) Use skb->len in xt_length to deal with IPv6 jumbo packets,
from Xin Long.
7) Fix NETLINK_LISTEN_ALL_NSID with ctnetlink, from Florian Westphal.
8) Fix memleak in {ip_,ip6_,arp_}tables in ENOMEM error case,
from Pavel Tikhomirov.
* git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf:
netfilter: x_tables: fix percpu counter block leak on error path when creating new netns
netfilter: ctnetlink: make event listener tracking global
netfilter: xt_length: use skb len to match in length_mt6
netfilter: ebtables: fix table blob use-after-free
netfilter: ip6t_rpfilter: Fix regression with VRF interfaces
netfilter: conntrack: fix rmmod double-free race
netfilter: ctnetlink: fix possible refcount leak in ctnetlink_create_conntrack()
netfilter: nf_tables: allow to fetch set elements when table has an owner
====================
Link: https://lore.kernel.org/r/20230222092137.88637-1-pablo@netfilter.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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pernet tracking doesn't work correctly because other netns might have
set NETLINK_LISTEN_ALL_NSID on its event socket.
In this case its expected that events originating in other net
namespaces are also received.
Making pernet-tracking work while also honoring NETLINK_LISTEN_ALL_NSID
requires much more intrusive changes both in netlink and nfnetlink,
f.e. adding a 'setsockopt' callback that lets nfnetlink know that the
event socket entered (or left) ALL_NSID mode.
Move to global tracking instead: if there is an event socket anywhere
on the system, all net namespaces which have conntrack enabled and
use autobind mode will allocate the ecache extension.
netlink_has_listeners() returns false only if the given group has no
subscribers in any net namespace, the 'net' argument passed to
nfnetlink_has_listeners is only used to derive the protocol (nfnetlink),
it has no other effect.
For proper NETLINK_LISTEN_ALL_NSID-aware pernet tracking of event
listeners a new netlink_has_net_listeners() is also needed.
Fixes: 90d1daa45849 ("netfilter: conntrack: add nf_conntrack_events autodetect mode")
Reported-by: Bryce Kahle <bryce.kahle@datadoghq.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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iptables/nftables support responding to tcp packets with tcp resets.
The generated tcp reset packet passes through both output and postrouting
netfilter hooks, but conntrack will never see them because the generated
skb has its ->nfct pointer copied over from the packet that triggered the
reset rule.
If the reset rule is used for established connections, this
may result in the conntrack entry to be around for a very long
time (default timeout is 5 days).
One way to avoid this would be to not copy the nf_conn pointer
so that the rest packet passes through conntrack too.
Problem is that output rules might not have the same conntrack
zone setup as the prerouting ones, so its possible that the
reset skb won't find the correct entry. Generating a template
entry for the skb seems error prone as well.
Add an explicit "closing" function that switches a confirmed
conntrack entry to closed state and wire this up for tcp.
If the entry isn't confirmed, no action is needed because
the conntrack entry will never be committed to the table.
Reported-by: Russel King <linux@armlinux.org.uk>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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DECnet is an obsolete network protocol that receives more attention
from kernel janitors than users. It belongs in computer protocol
history museum not in Linux kernel.
It has been "Orphaned" in kernel since 2010. The iproute2 support
for DECnet was dropped in 5.0 release. The documentation link on
Sourceforge says it is abandoned there as well.
Leave the UAPI alone to keep userspace programs compiling.
This means that there is still an empty neighbour table
for AF_DECNET.
The table of /proc/sys/net entries was updated to match
current directories and reformatted to be alphabetical.
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Acked-by: David Ahern <dsahern@kernel.org>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The nat module already exposes a few functions to the conntrack core.
Move the nat extension destroy hook to it.
After this, no conntrack extension needs a destroy hook.
'struct nf_ct_ext_type' and the register/unregister api can be removed
in a followup patch.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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No functional changes, these structures should be const.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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ip_ct_attach predates struct nf_ct_hook, we can place it there and
remove the exported symbol.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This will allow a followup patch to treat the 'ops->priv' pointer
as nft_chain argument without having to first walk the table/chains
to check if there is a matching base chain pointer.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Reduce size from 28 to 24 bytes on 32bit platforms.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Use nf_ct_get() directly, its a small inline helper without dependencies.
Add CONFIG_NF_CONNTRACK guards to elide the relevant part when conntrack
isn't available at all.
v2: add ifdef guard around nf_ct_get call (kernel test robot)
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Pass a sockptr_t to prepare for set_fs-less handling of the kernel
pointer from bpf-cgroup.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
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All instances handle compat sockopts via in_compat_syscall() now, so
remove the compat_{get,set} methods as well as the
compat_nf_{get,set}sockopt wrappers.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
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At this time, NF_HOOK_LIST() macro will iterate the list and then calls
nf_hook() for each individual skb.
This makes it so the entire list is passed into the netfilter core.
The advantage is that we only need to fetch the rule blob once per list
instead of per-skb.
NF_HOOK_LIST now only works for ipv4 and ipv6, as those are the only
callers.
v2: use skb_list_del_init() instead of list_del (Edward Cree)
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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`struct nf_hook_ops`, `struct nf_hook_state` and the `nf_hookfn`
function typedef appear in function and struct declarations and
definitions in a number of netfilter headers. The structs and typedef
themselves are defined by linux/netfilter.h but only when
CONFIG_NETFILTER is enabled. Define them unconditionally and add
forward declarations in order to remove CONFIG_NETFILTER conditionals
from the other headers.
Signed-off-by: Jeremy Sowden <jeremy@azazel.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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IS_ENABLED(CONFIG...).
A few headers contain instances of:
#if defined(CONFIG_XXX) or defined(CONFIG_XXX_MODULE)
Replace them with:
#if IS_ENABLED(CONFIG_XXX)
Signed-off-by: Jeremy Sowden <jeremy@azazel.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This converts all remaining users and then removes skb_make_writable.
Suggested-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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using 64bit computation to slightly optimize nf_inet_addr_mask
Signed-off-by: Li RongQing <lirongqing@baidu.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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NF_NAT_NEEDED is true whenever nat support for either ipv4 or ipv6 is
enabled. Now that the af-specific nat configuration switches have been
removed, IS_ENABLED(CONFIG_NF_NAT) has the same effect.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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optimize nf_inet_addr_cmp by 64bit xor computation
similar to ipv6_addr_equal()
Signed-off-by: Yuan Linsi <yuanlinsi01@baidu.com>
Signed-off-by: Li RongQing <lirongqing@baidu.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Currently, CONFIG_JUMP_LABEL just means "I _want_ to use jump label".
The jump label is controlled by HAVE_JUMP_LABEL, which is defined
like this:
#if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL)
# define HAVE_JUMP_LABEL
#endif
We can improve this by testing 'asm goto' support in Kconfig, then
make JUMP_LABEL depend on CC_HAS_ASM_GOTO.
Ugly #ifdef HAVE_JUMP_LABEL will go away, and CONFIG_JUMP_LABEL will
match to the real kernel capability.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
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Unfortunately some versions of gcc emit following warning:
$ make net/xfrm/xfrm_output.o
linux/compiler.h:252:20: warning: array subscript is above array bounds [-Warray-bounds]
hook_head = rcu_dereference(net->nf.hooks_arp[hook]);
^~~~~~~~~~~~~~~~~~~~~
xfrm_output_resume passes skb_dst(skb)->ops->family as its 'pf' arg so compiler
can't know that we'll never access hooks_arp[].
(NFPROTO_IPV4 or NFPROTO_IPV6 are only possible cases).
Avoid this by adding an explicit WARN_ON_ONCE() check.
This patch has no effect if the family is a compile-time constant as gcc
will remove the switch() construct entirely.
Reported-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This adds a global netfilter function to extract a conntrack tuple from an
skb. The function uses a new function added to nf_ct_hook, which will try
to get the tuple from skb->_nfct, and do a full lookup if that fails. This
makes it possible to use the lookup function before the skb has passed
through the conntrack init hooks (e.g., in an ingress qdisc). The tuple is
copied to the caller to avoid issues with reference counting.
The function returns false if conntrack is not loaded, allowing it to be
used without incurring a module dependency on conntrack. This is used by
the NAT mode in sch_cake.
Cc: netfilter-devel@vger.kernel.org
Signed-off-by: Toke Høiland-Jørgensen <toke@toke.dk>
Signed-off-by: David S. Miller <davem@davemloft.net>
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nf_hook() can free the skb, so we need to remove it from the list before
calling, and add passed skbs to a sublist afterwards.
Fixes: 17266ee93984 ("net: ipv4: listified version of ip_rcv")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Also involved adding a way to run a netfilter hook over a list of packets.
Rather than attempting to make netfilter know about lists (which would be
a major project in itself) we just let it call the regular okfn (in this
case ip_rcv_finish()) for any packets it steals, and have it give us back
a list of packets it's synchronously accepted (which normally NF_HOOK
would automatically call okfn() on, but we want to be able to potentially
pass the list to a listified version of okfn().)
The netfilter hooks themselves are indirect calls that still happen per-
packet (see nf_hook_entry_hookfn()), but again, changing that can be left
for future work.
There is potential for out-of-order receives if the netfilter hook ends up
synchronously stealing packets, as they will be processed before any
accepts earlier in the list. However, it was already possible for an
asynchronous accept to cause out-of-order receives, so presumably this is
considered OK.
Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Add null check for nat_hook in nf_nat_decode_session()
[ 195.648098] UBSAN: Undefined behaviour in ./include/linux/netfilter.h:348:14
[ 195.651366] BUG: KASAN: null-ptr-deref in __xfrm_policy_check+0x208/0x1d70
[ 195.653888] member access within null pointer of type 'struct nf_nat_hook'
[ 195.653896] CPU: 3 PID: 0 Comm: swapper/3 Not tainted 4.17.0-rc6+ #5
[ 195.656320] Read of size 8 at addr 0000000000000008 by task ping/2469
[ 195.658715] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
[ 195.658721] Call Trace:
[ 195.661087]
[ 195.669341] <IRQ>
[ 195.670574] dump_stack+0xc6/0x150
[ 195.672156] ? dump_stack_print_info.cold.0+0x1b/0x1b
[ 195.674121] ? ubsan_prologue+0x31/0x92
[ 195.676546] ubsan_epilogue+0x9/0x49
[ 195.678159] handle_null_ptr_deref+0x11a/0x130
[ 195.679800] ? sprint_OID+0x1a0/0x1a0
[ 195.681322] __ubsan_handle_type_mismatch_v1+0xd5/0x11d
[ 195.683146] ? ubsan_prologue+0x92/0x92
[ 195.684642] __xfrm_policy_check+0x18ef/0x1d70
[ 195.686294] ? rt_cache_valid+0x118/0x180
[ 195.687804] ? __xfrm_route_forward+0x410/0x410
[ 195.689463] ? fib_multipath_hash+0x700/0x700
[ 195.691109] ? kvm_sched_clock_read+0x23/0x40
[ 195.692805] ? pvclock_clocksource_read+0xf6/0x280
[ 195.694409] ? graph_lock+0xa0/0xa0
[ 195.695824] ? pvclock_clocksource_read+0xf6/0x280
[ 195.697508] ? pvclock_read_flags+0x80/0x80
[ 195.698981] ? kvm_sched_clock_read+0x23/0x40
[ 195.700347] ? sched_clock+0x5/0x10
[ 195.701525] ? sched_clock_cpu+0x18/0x1a0
[ 195.702846] tcp_v4_rcv+0x1d32/0x1de0
[ 195.704115] ? lock_repin_lock+0x70/0x270
[ 195.707072] ? pvclock_read_flags+0x80/0x80
[ 195.709302] ? tcp_v4_early_demux+0x4b0/0x4b0
[ 195.711833] ? lock_acquire+0x195/0x380
[ 195.714222] ? ip_local_deliver_finish+0xfc/0x770
[ 195.716967] ? raw_rcv+0x2b0/0x2b0
[ 195.718856] ? lock_release+0xa00/0xa00
[ 195.720938] ip_local_deliver_finish+0x1b9/0x770
[...]
Fixes: 2c205dd3981f ("netfilter: add struct nf_nat_hook and use it")
Signed-off-by: Prashant Bhole <bhole_prashant_q7@lab.ntt.co.jp>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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In nfqueue, two consecutive skbuffs may race to create the conntrack
entry. Hence, the one that loses the race gets dropped due to clash in
the insertion into the hashes from the nf_conntrack_confirm() path.
This patch adds a new nf_conntrack_update() function which searches for
possible clashes and resolve them. NAT mangling for the packet losing
race is corrected by using the conntrack information that won race.
In order to avoid direct module dependencies with conntrack and NAT, the
nf_ct_hook and nf_nat_hook structures are used for this purpose.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Move decode_session() and parse_nat_setup_hook() indirections to struct
nf_nat_hook structure.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Move the nf_ct_destroy indirection to the struct nf_ct_hook.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This reverts commit f92b40a8b2645
("netfilter: core: only allow one nat hook per hook point"), this
limitation is no longer needed. The nat core now invokes these
functions and makes sure that hook evaluation stops after a mapping is
created and a null binding is created otherwise.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This abstraction has no clients anymore, remove it.
This is what remains from previous authors, so correct copyright
statement after recent modifications and code removal.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This is only needed by nf_queue, place this code where it belongs.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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We cannot make a direct call to nf_ip6_reroute() because that would result
in autoloading the 'ipv6' module because of symbol dependencies.
Therefore, define reroute indirection in nf_ipv6_ops where this really
belongs to.
For IPv4, we can indeed make a direct function call, which is faster,
given IPv4 is built-in in the networking code by default. Still,
CONFIG_INET=n and CONFIG_NETFILTER=y is possible, so define empty inline
stub for IPv4 in such case.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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We cannot make a direct call to nf_ip6_route() because that would result
in autoloading the 'ipv6' module because of symbol dependencies.
Therefore, define route indirection in nf_ipv6_ops where this really
belongs to.
For IPv4, we can indeed make a direct function call, which is faster,
given IPv4 is built-in in the networking code by default. Still,
CONFIG_INET=n and CONFIG_NETFILTER=y is possible, so define empty inline
stub for IPv4 in such case.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This is only used by nf_queue.c and this function comes with no symbol
dependencies with IPv6, it just refers to structure layouts. Therefore,
we can replace it by a direct function call from where it belongs.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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We cannot make a direct call to nf_ip6_checksum_partial() because that
would result in autoloading the 'ipv6' module because of symbol
dependencies. Therefore, define checksum_partial indirection in
nf_ipv6_ops where this really belongs to.
For IPv4, we can indeed make a direct function call, which is faster,
given IPv4 is built-in in the networking code by default. Still,
CONFIG_INET=n and CONFIG_NETFILTER=y is possible, so define empty inline
stub for IPv4 in such case.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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We cannot make a direct call to nf_ip6_checksum() because that would
result in autoloading the 'ipv6' module because of symbol dependencies.
Therefore, define checksum indirection in nf_ipv6_ops where this really
belongs to.
For IPv4, we can indeed make a direct function call, which is faster,
given IPv4 is built-in in the networking code by default. Still,
CONFIG_INET=n and CONFIG_NETFILTER=y is possible, so define empty inline
stub for IPv4 in such case.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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The netfilter NAT core cannot deal with more than one NAT hook per hook
location (prerouting, input ...), because the NAT hooks install a NAT null
binding in case the iptables nat table (iptable_nat hooks) or the
corresponding nftables chain (nft nat hooks) doesn't specify a nat
transformation.
Null bindings are needed to detect port collsisions between NAT-ed and
non-NAT-ed connections.
This causes nftables NAT rules to not work when iptable_nat module is
loaded, and vice versa because nat binding has already been attached
when the second nat hook is consulted.
The netfilter core is not really the correct location to handle this
(hooks are just hooks, the core has no notion of what kinds of side
effects a hook implements), but its the only place where we can check
for conflicts between both iptables hooks and nftables hooks without
adding dependencies.
So add nat annotation to hook_ops to describe those hooks that will
add NAT bindings and then make core reject if such a hook already exists.
The annotation fills a padding hole, in case further restrictions appar
we might change this to a 'u8 type' instead of bool.
iptables error if nft nat hook active:
iptables -t nat -A POSTROUTING -j MASQUERADE
iptables v1.4.21: can't initialize iptables table `nat': File exists
Perhaps iptables or your kernel needs to be upgraded.
nftables error if iptables nat table present:
nft -f /etc/nftables/ipv4-nat
/usr/etc/nftables/ipv4-nat:3:1-2: Error: Could not process rule: File exists
table nat {
^^
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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no need to define hook points if the family isn't supported.
Because we need these hooks for either nftables, arp/ebtables
or the 'call-iptables' hack we have in the bridge layer add two
new dependencies, NETFILTER_FAMILY_{ARP,BRIDGE}, and have the
users select them.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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no need to define hook points if the family isn't supported.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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