linux-stable.git/net/netfilter, branch v6.2.6

netfilter: ctnetlink: make event listener tracking global

2023-03-11T12:50:30+00:00

[ Upstream commit fdf6491193e411087ae77bcbc6468e3e1cff99ed ]

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

netfilter: xt_length: use skb len to match in length_mt6

2023-03-11T12:50:30+00:00

[ Upstream commit 05c07c0c6cc8ec2278ace9871618c41f1365d1f5 ]

For IPv6 Jumbo packets, the ipv6_hdr(skb)->payload_len is always 0,
and its real payload_len ( > 65535) is saved in hbh exthdr. With 0
length for the jumbo packets, it may mismatch.

To fix this, we can just use skb->len instead of parsing exthdrs, as
the hbh exthdr parsing has been done before coming to length_mt6 in
ip6_rcv_core() and br_validate_ipv6() and also the packet has been
trimmed according to the correct IPv6 (ext)hdr length there, and skb
len is trustable in length_mt6().

Note that this patch is especially needed after the IPv6 BIG TCP was
supported in kernel, which is using IPv6 Jumbo packets. Besides, to
match the packets greater than 65535 more properly, a v1 revision of
xt_length may be needed to extend "min, max" to u32 in the future,
and for now the IPv6 Jumbo packets can be matched by:

  # ip6tables -m length ! --length 0:65535

Fixes: 7c4e983c4f3c ("net: allow gso_max_size to exceed 65536")
Fixes: 0fe79f28bfaf ("net: allow gro_max_size to exceed 65536")
Signed-off-by: Xin Long 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Sasha Levin

netfilter: conntrack: fix rmmod double-free race

2023-03-11T12:50:29+00:00

[ Upstream commit e6d57e9ff0aec323717ee36fc9ea34ad89217151 ]

nf_conntrack_hash_check_insert() callers free the ct entry directly, via
nf_conntrack_free.

This isn't safe anymore because
nf_conntrack_hash_check_insert() might place the entry into the conntrack
table and then delteted the entry again because it found that a conntrack
extension has been removed at the same time.

In this case, the just-added entry is removed again and an error is
returned to the caller.

Problem is that another cpu might have picked up this entry and
incremented its reference count.

This results in a use-after-free/double-free, once by the other cpu and
once by the caller of nf_conntrack_hash_check_insert().

Fix this by making nf_conntrack_hash_check_insert() not fail anymore
after the insertion, just like before the 'Fixes' commit.

This is safe because a racing nf_ct_iterate() has to wait for us
to release the conntrack hash spinlocks.

While at it, make the function return -EAGAIN in the rmmod (genid
changed) case, this makes nfnetlink replay the command (suggested
by Pablo Neira).

Fixes: c56716c69ce1 ("netfilter: extensions: introduce extension genid count")
Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Sasha Levin

netfilter: ctnetlink: fix possible refcount leak in ctnetlink_create_conntrack()

2023-03-11T12:50:29+00:00

[ Upstream commit ac4893980bbe79ce383daf9a0885666a30fe4c83 ]

nf_ct_put() needs to be called to put the refcount got by
nf_conntrack_find_get() to avoid refcount leak when
nf_conntrack_hash_check_insert() fails.

Fixes: 7d367e06688d ("netfilter: ctnetlink: fix soft lockup when netlink adds new entries (v2)")
Signed-off-by: Hangyu Hua 
Acked-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Sasha Levin

netfilter: nf_tables: allow to fetch set elements when table has an owner

2023-03-11T12:50:27+00:00

[ Upstream commit 92f3e96d642f5e05b9dc710c06fedc669f1b4f00 ]

NFT_MSG_GETSETELEM returns -EPERM when fetching set elements that belong
to table that has an owner. This results in empty set/map listing from
userspace.

Fixes: 6001a930ce03 ("netfilter: nftables: introduce table ownership")
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Sasha Levin

netfilter: nf_tables: NULL pointer dereference in nf_tables_updobj()

2023-03-10T08:29:11+00:00

[ Upstream commit dac7f50a45216d652887fb92d6cd3b7ca7f006ea ]

static analyzer detect null pointer dereference case for 'type'
function __nft_obj_type_get() can return NULL value which require to handle
if type is NULL pointer return -ENOENT.

This is a theoretical issue, since an existing object has a type, but
better add this failsafe check.

Signed-off-by: Alok Tiwari 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Sasha Levin

Revert "netfilter: conntrack: fix bug in for_each_sctp_chunk"

2023-01-31T13:02:48+00:00

There is no bug.  If sch->length == 0, this would result in an infinite
loop, but first caller, do_basic_checks(), errors out in this case.

After this change, packets with bogus zero-length chunks are no longer
detected as invalid, so revert & add comment wrt. 0 length check.

Fixes: 98ee00774525 ("netfilter: conntrack: fix bug in for_each_sctp_chunk")
Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso

netfilter: conntrack: unify established states for SCTP paths

2023-01-24T08:52:52+00:00

An SCTP endpoint can start an association through a path and tear it
down over another one. That means the initial path will not see the
shutdown sequence, and the conntrack entry will remain in ESTABLISHED
state for 5 days.

By merging the HEARTBEAT_ACKED and ESTABLISHED states into one
ESTABLISHED state, there remains no difference between a primary or
secondary path. The timeout for the merged ESTABLISHED state is set to
210 seconds (hb_interval * max_path_retrans + rto_max). So, even if a
path doesn't see the shutdown sequence, it will expire in a reasonable
amount of time.

With this change in place, there is now more than one state from which
we can transition to ESTABLISHED, COOKIE_ECHOED and HEARTBEAT_SENT, so
handle the setting of ASSURED bit whenever a state change has happened
and the new state is ESTABLISHED. Removed the check for dir==REPLY since
the transition to ESTABLISHED can happen only in the reply direction.

Fixes: 9fb9cbb1082d ("[NETFILTER]: Add nf_conntrack subsystem.")
Signed-off-by: Sriram Yagnaraman 
Signed-off-by: Pablo Neira Ayuso

Revert "netfilter: conntrack: add sctp DATA_SENT state"

2023-01-24T08:52:32+00:00

This reverts commit (bff3d0534804: "netfilter: conntrack: add sctp
DATA_SENT state")

Using DATA/SACK to detect a new connection on secondary/alternate paths
works only on new connections, while a HEARTBEAT is required on
connection re-use. It is probably consistent to wait for HEARTBEAT to
create a secondary connection in conntrack.

Signed-off-by: Sriram Yagnaraman 
Signed-off-by: Pablo Neira Ayuso

netfilter: conntrack: fix bug in for_each_sctp_chunk

2023-01-24T08:52:31+00:00

skb_header_pointer() will return NULL if offset + sizeof(_sch) exceeds
skb->len, so this offset < skb->len test is redundant.

if sch->length == 0, this will end up in an infinite loop, add a check
for sch->length > 0

Fixes: 9fb9cbb1082d ("[NETFILTER]: Add nf_conntrack subsystem.")
Suggested-by: Florian Westphal 
Signed-off-by: Sriram Yagnaraman 
Signed-off-by: Pablo Neira Ayuso