While reading sysctl_ip_default_ttl, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its readers.
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
BUG_ON can be triggered from userspace with an element with a large
userdata area. Replace it by length check and return EINVAL instead.
Over time extensions have been growing in size.
Pick a sufficiently old Fixes: tag to propagate this fix.
Fixes: 7d7402642e ("netfilter: nf_tables: variable sized set element keys / data")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
NFPROTO_ARP is expecting to find the ARP header at the network offset.
In the particular case of ARP, HTYPE= field shows the initial bytes of
the ethernet header destination MAC address.
netdev out: IN= OUT=bridge0 MACSRC=c2:76:e5:71:e1:de MACDST=36:b0:4a:e2:72:ea MACPROTO=0806 ARP HTYPE=14000 PTYPE=0x4ae2 OPCODE=49782
NFPROTO_NETDEV egress hook is also expecting to find the IP headers at
the network offset.
Fixes: 35b9395104 ("netfilter: add generic ARP packet logger")
Reported-by: Tom Yan <tom.ty89@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Kajetan Puchalski reports crash on ARM, with backtrace of:
__nf_ct_delete_from_lists
nf_ct_delete
early_drop
__nf_conntrack_alloc
Unlike atomic_inc_not_zero, refcount_inc_not_zero is not a full barrier.
conntrack uses SLAB_TYPESAFE_BY_RCU, i.e. it is possible that a 'newly'
allocated object is still in use on another CPU:
CPU1 CPU2
encounter 'ct' during hlist walk
delete_from_lists
refcount drops to 0
kmem_cache_free(ct);
__nf_conntrack_alloc() // returns same object
refcount_inc_not_zero(ct); /* might fail */
/* If set, ct is public/in the hash table */
test_bit(IPS_CONFIRMED_BIT, &ct->status);
In case CPU1 already set refcount back to 1, refcount_inc_not_zero()
will succeed.
The expected possibilities for a CPU that obtained the object 'ct'
(but no reference so far) are:
1. refcount_inc_not_zero() fails. CPU2 ignores the object and moves to
the next entry in the list. This happens for objects that are about
to be free'd, that have been free'd, or that have been reallocated
by __nf_conntrack_alloc(), but where the refcount has not been
increased back to 1 yet.
2. refcount_inc_not_zero() succeeds. CPU2 checks the CONFIRMED bit
in ct->status. If set, the object is public/in the table.
If not, the object must be skipped; CPU2 calls nf_ct_put() to
un-do the refcount increment and moves to the next object.
Parallel deletion from the hlists is prevented by a
'test_and_set_bit(IPS_DYING_BIT, &ct->status);' check, i.e. only one
cpu will do the unlink, the other one will only drop its reference count.
Because refcount_inc_not_zero is not a full barrier, CPU2 may try to
delete an object that is not on any list:
1. refcount_inc_not_zero() successful (refcount inited to 1 on other CPU)
2. CONFIRMED test also successful (load was reordered or zeroing
of ct->status not yet visible)
3. delete_from_lists unlinks entry not on the hlist, because
IPS_DYING_BIT is 0 (already cleared).
2) is already wrong: CPU2 will handle a partially initited object
that is supposed to be private to CPU1.
Add needed barriers when refcount_inc_not_zero() is successful.
It also inserts a smp_wmb() before the refcount is set to 1 during
allocation.
Because other CPU might still see the object, refcount_set(1)
"resurrects" it, so we need to make sure that other CPUs will also observe
the right content. In particular, the CONFIRMED bit test must only pass
once the object is fully initialised and either in the hash or about to be
inserted (with locks held to delay possible unlink from early_drop or
gc worker).
I did not change flow_offload_alloc(), as far as I can see it should call
refcount_inc(), not refcount_inc_not_zero(): the ct object is attached to
the skb so its refcount should be >= 1 in all cases.
v2: prefer smp_acquire__after_ctrl_dep to smp_rmb (Will Deacon).
v3: keep smp_acquire__after_ctrl_dep close to refcount_inc_not_zero call
add comment in nf_conntrack_netlink, no control dependency there
due to locks.
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/all/Yr7WTfd6AVTQkLjI@e126311.manchester.arm.com/
Reported-by: Kajetan Puchalski <kajetan.puchalski@arm.com>
Diagnosed-by: Will Deacon <will@kernel.org>
Fixes: 7197743776 ("netfilter: conntrack: convert to refcount_t api")
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Will Deacon <will@kernel.org>
New elements that reside in the clone are not released in case that the
transaction is aborted.
[16302.231754] ------------[ cut here ]------------
[16302.231756] WARNING: CPU: 0 PID: 100509 at net/netfilter/nf_tables_api.c:1864 nf_tables_chain_destroy+0x26/0x127 [nf_tables]
[...]
[16302.231882] CPU: 0 PID: 100509 Comm: nft Tainted: G W 5.19.0-rc3+ #155
[...]
[16302.231887] RIP: 0010:nf_tables_chain_destroy+0x26/0x127 [nf_tables]
[16302.231899] Code: f3 fe ff ff 41 55 41 54 55 53 48 8b 6f 10 48 89 fb 48 c7 c7 82 96 d9 a0 8b 55 50 48 8b 75 58 e8 de f5 92 e0 83 7d 50 00 74 09 <0f> 0b 5b 5d 41 5c 41 5d c3 4c 8b 65 00 48 8b 7d 08 49 39 fc 74 05
[...]
[16302.231917] Call Trace:
[16302.231919] <TASK>
[16302.231921] __nf_tables_abort.cold+0x23/0x28 [nf_tables]
[16302.231934] nf_tables_abort+0x30/0x50 [nf_tables]
[16302.231946] nfnetlink_rcv_batch+0x41a/0x840 [nfnetlink]
[16302.231952] ? __nla_validate_parse+0x48/0x190
[16302.231959] nfnetlink_rcv+0x110/0x129 [nfnetlink]
[16302.231963] netlink_unicast+0x211/0x340
[16302.231969] netlink_sendmsg+0x21e/0x460
Add nft_set_pipapo_match_destroy() helper function to release the
elements in the lookup tables.
Stefano Brivio says: "We additionally look for elements pointers in the
cloned matching data if priv->dirty is set, because that means that
cloned data might point to additional elements we did not commit to the
working copy yet (such as the abort path case, but perhaps not limited
to it)."
Fixes: 3c4287f620 ("nf_tables: Add set type for arbitrary concatenation of ranges")
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Make sure element data type and length do not mismatch the one specified
by the set declaration.
Fixes: 7d7402642e ("netfilter: nf_tables: variable sized set element keys / data")
Reported-by: Hugues ANGUELKOV <hanguelkov@randorisec.fr>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
When verdict is NF_STOLEN, the skb might have been freed.
When tracing is enabled, this can result in a use-after-free:
1. access to skb->nf_trace
2. access to skb->mark
3. computation of trace id
4. dump of packet payload
To avoid 1, keep a cached copy of skb->nf_trace in the
trace state struct.
Refresh this copy whenever verdict is != STOLEN.
Avoid 2 by skipping skb->mark access if verdict is STOLEN.
3 is avoided by precomputing the trace id.
Only dump the packet when verdict is not "STOLEN".
Reported-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This patch fixes a race condition.
nft_rhash_update() might fail for two reasons:
- Element already exists in the hashtable.
- Another packet won race to insert an entry in the hashtable.
In both cases, new() has already bumped the counter via atomic_add_unless(),
therefore, decrement the set element counter.
Fixes: 22fe54d5fe ("netfilter: nf_tables: add support for dynamic set updates")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Now that the egress function can be called from egress hook, we need
to avoid recursive calls into the nf_tables traverser, else crash.
Fixes: f87b9464d1 ("netfilter: nft_fwd_netdev: Support egress hook")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Eric reports skb_under_panic when using dup/fwd via bond+egress hook.
Before pushing mac header, we should make sure that we're called from
ingress to put back what was pulled earlier.
In egress case, the MAC header is already there; we should leave skb
alone.
While at it be more careful here: skb might have been altered and
headroom reduced, so add a skb_cow() before so that headroom is
increased if necessary.
nf_do_netdev_egress() assumes skb ownership (it normally ends with
a call to dev_queue_xmit), so we must free the packet on error.
Fixes: f87b9464d1 ("netfilter: nft_fwd_netdev: Support egress hook")
Reported-by: Eric Garver <eric@garver.life>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
syzbot reports:
BUG: KASAN: slab-out-of-bounds in __list_del_entry_valid+0xcc/0xf0 lib/list_debug.c:42
[..]
list_del include/linux/list.h:148 [inline]
cttimeout_net_exit+0x211/0x540 net/netfilter/nfnetlink_cttimeout.c:617
Problem is the wrong name of the list member, so container_of() result is wrong.
Reported-by: <syzbot+92968395eedbdbd3617d@syzkaller.appspotmail.com>
Fixes: 78222bacfc ("netfilter: cttimeout: decouple unlink and free on netns destruction")
Signed-off-by: Florian Westphal <fw@strlen.de>
bh might occur while updating per-cpu rnd_state from user context,
ie. local_out path.
BUG: using smp_processor_id() in preemptible [00000000] code: nginx/2725
caller is nft_ng_random_eval+0x24/0x54 [nft_numgen]
Call Trace:
check_preemption_disabled+0xde/0xe0
nft_ng_random_eval+0x24/0x54 [nft_numgen]
Use the random driver instead, this also avoids need for local prandom
state. Moreover, prandom now uses the random driver since d4150779e6
("random32: use real rng for non-deterministic randomness").
Based on earlier patch from Pablo Neira.
Fixes: 6b2faee0ca ("netfilter: nft_meta: place prandom handling in a helper")
Fixes: 978d8f9055 ("netfilter: nft_numgen: add map lookups for numgen random operations")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
If user requests for NFT_CHAIN_HW_OFFLOAD, then check if either device
provides the .ndo_setup_tc interface or there is an indirect flow block
that has been registered. Otherwise, bail out early from the preparation
phase. Moreover, validate that family == NFPROTO_NETDEV and hook is
NF_NETDEV_INGRESS.
Fixes: c9626a2cbd ("netfilter: nf_tables: add hardware offload support")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Abort path release flow rule object, however, commit path does not.
Update code to destroy these objects before releasing the transaction.
Fixes: c9626a2cbd ("netfilter: nf_tables: add hardware offload support")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Release the list of new hooks that are pending to be registered in case
that unsupported flowtable flags are provided.
Fixes: 78d9f48f7f ("netfilter: nf_tables: add devices to existing flowtable")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The hook list is used if nft_trans_flowtable_update(trans) == true. However,
initialize this list for other cases for safety reasons.
Fixes: 78d9f48f7f ("netfilter: nf_tables: add devices to existing flowtable")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Remove inactive bool field in nft_hook object that was introduced in
abadb2f865 ("netfilter: nf_tables: delete devices from flowtable").
Move stale flowtable hooks to transaction list instead.
Deleting twice the same device does not result in ENOENT.
Fixes: abadb2f865 ("netfilter: nf_tables: delete devices from flowtable")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Use kfree_rcu(ptr, rcu) variant instead as described by ae089831ff
("netfilter: nf_tables: prefer kfree_rcu(ptr, rcu) variant").
Fixes: f9a43007d3 ("netfilter: nf_tables: double hook unregistration in netns path")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
When no l3 address is given, priv->family is set to NFPROTO_INET and
the evaluation function isn't called.
Call it too so l4-only rewrite can work.
Also add a test case for this.
Fixes: a33f387ecd ("netfilter: nft_nat: allow to specify layer 4 protocol NAT only")
Reported-by: Yi Chen <yiche@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
For snat and dnat cases, the saddr should be taken from reverse tuple.
Fixes: 3412e16418 (netfilter: flowtable: nft_flow_route use more data for reverse route)
Signed-off-by: wenxu <wenxu@chinatelecom.cn>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The nf_flow_table gets route through ip_route_output_key. If the saddr
is not local one, then FLOWI_FLAG_ANYSRC flag should be set. Without
this flag, the route lookup for other_dst will fail.
Fixes: 3412e16418 (netfilter: flowtable: nft_flow_route use more data for reverse route)
Signed-off-by: wenxu <wenxu@chinatelecom.cn>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
__nft_release_hooks() is called from pre_netns exit path which
unregisters the hooks, then the NETDEV_UNREGISTER event is triggered
which unregisters the hooks again.
[ 565.221461] WARNING: CPU: 18 PID: 193 at net/netfilter/core.c:495 __nf_unregister_net_hook+0x247/0x270
[...]
[ 565.246890] CPU: 18 PID: 193 Comm: kworker/u64:1 Tainted: G E 5.18.0-rc7+ #27
[ 565.253682] Workqueue: netns cleanup_net
[ 565.257059] RIP: 0010:__nf_unregister_net_hook+0x247/0x270
[...]
[ 565.297120] Call Trace:
[ 565.300900] <TASK>
[ 565.304683] nf_tables_flowtable_event+0x16a/0x220 [nf_tables]
[ 565.308518] raw_notifier_call_chain+0x63/0x80
[ 565.312386] unregister_netdevice_many+0x54f/0xb50
Unregister and destroy netdev hook from netns pre_exit via kfree_rcu
so the NETDEV_UNREGISTER path see unregistered hooks.
Fixes: 767d1216bf ("netfilter: nftables: fix possible UAF over chains from packet path in netns")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
clean_net() runs in workqueue while walking over the lists, grab mutex.
Fixes: 767d1216bf ("netfilter: nftables: fix possible UAF over chains from packet path in netns")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Add several sanity checks for nft_set_desc_concat_parse():
- validate desc->field_count not larger than desc->field_len array.
- field length cannot be larger than desc->field_len (ie. U8_MAX)
- total length of the concatenation cannot be larger than register array.
Joint work with Florian Westphal.
Fixes: f3a2181e16 ("netfilter: nf_tables: Support for sets with multiple ranged fields")
Reported-by: <zhangziming.zzm@antgroup.com>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
