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... and must not be subjected to the 'nul terminated' constraint.
If the interface name is 15 characters long, the mask is 16-bytes
'0xff' (to cover for \0) and the valid device name is rejected.
Fixes: 8df772afc9d0 ("netfilter: x_physdev: reject empty or not-nul terminated device names")
Cc: stable@vger.kernel.org
Closes: https://bugs.launchpad.net/neutron/+bug/2159935
Signed-off-by: Florian Westphal <fw@strlen.de>
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Sashiko reports for more incorrect IPv6 transport offsets.
The app code for TCP was assuming IPv4 network header
even after the ipvsh argument was provided. This can
cause problems with apps over IPv6. As for the only
official app in the kernel tree (FTP) this problem is
harmless because we use Netfilter to mangle the FTP
ports and we do not adjust the TCP seq numbers.
Also, provide correct offset of the ICMPV6 header in
ip_vs_out_icmp_v6() for correct checksum checks when
the IPv6 packet has extension headers.
Fixes: d12e12299a69 ("ipvs: add ipv6 support to ftp")
Fixes: 2a3b791e6e11 ("IPVS: Add/adjust Netfilter hook functions and helpers for v6")
Cc: stable@vger.kernel.org
Link: https://sashiko.dev/#/patchset/20260706101624.69471-1-zhaoyz24%40mails.tsinghua.edu.cn
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Florian Westphal <fw@strlen.de>
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__ip_vs_get_out_rt() calls skb_ensure_writable() which may
reallocate skb->head.
Fixes: 8d8e20e2d7bb ("ipvs: Decrement ttl")
Cc: stable@vger.kernel.org
Assisted-by: Claude:claude-sonnet-4-6
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Florian Westphal <fw@strlen.de>
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The layer 2 encapsulation and layer 3 tunnel information in the xmit
path is taken from the other tuple, because the tunnel information that
is included in the tuple for hashtable lookups is also used to perform
the egress encapsulation in the transmit path.
This patch uses the correct direction when setting up the tunnel, the
original proposed patch to address this fix uses the reversed direction.
While at it, remove the redundant check to call dst_release() to drop
the reference on the dst that was obtained from the forward path, which
is not useful in the direct xmit path unless tunneling is performed.
Fixes: fa7395c02d95 ("netfilter: flowtable: support IPIP tunnel with direct xmit")
Cc: stable@vger.kernel.org
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
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The "already exists" dedup logic in __nf_conncount_add() decides
whether a connection has already been counted and can be skipped instead
of incrementing the connlimit count. It compares the conntrack zone of a
list entry with the zone of the connection being added using
nf_ct_zone_id() and nf_ct_zone_equal(), passing conn->zone.dir or
zone->dir as the direction argument.
Those helpers take enum ip_conntrack_dir values: IP_CT_DIR_ORIGINAL is 0
and IP_CT_DIR_REPLY is 1. However, zone->dir is a u8 bitmask:
NF_CT_ZONE_DIR_ORIG is 1, NF_CT_ZONE_DIR_REPL is 2 and
NF_CT_DEFAULT_ZONE_DIR is 3. Passing that bitmask as the enum direction
shifts the meaning of every non-zero value. An ORIG-only zone passes 1
and is tested as REPLY, while REPL-only and default zones pass 2 or 3 and
test bits beyond the valid direction range. In those cases
nf_ct_zone_id() can fall back to NF_CT_DEFAULT_ZONE_ID instead of using
the real zone id, so different zones can be treated as equal and dedup
collapses to tuple equality alone.
nf_conncount stores and compares the original-direction tuple for a
connection. If an skb already has an attached conntrack entry,
get_ct_or_tuple_from_skb() explicitly copies
ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, regardless of the packet's
ctinfo. Therefore the zone comparison in the tuple dedup path must use
IP_CT_DIR_ORIGINAL as well; the zone direction bitmask describes where a
zone id applies, not which direction this conncount tuple represents.
Fix the two dedup comparisons by passing IP_CT_DIR_ORIGINAL directly.
Do not special-case NF_CT_DEFAULT_ZONE_DIR and do not compare raw zone
ids: using the existing helpers with IP_CT_DIR_ORIGINAL preserves the
direction-aware NF_CT_DEFAULT_ZONE_ID fallback. A default bidirectional
zone contains the ORIG bit, so it naturally returns the real zone id;
reply-only zones continue to fall back for original-direction tuple
comparisons.
Fixes: 21ba8847f857 ("netfilter: nf_conncount: Fix garbage collection with zones")
Fixes: b36e4523d4d5 ("netfilter: nf_conncount: fix garbage collection confirm race")
Cc: stable@vger.kernel.org
Reported-by: Yizhou Zhao <zhaoyz24@mails.tsinghua.edu.cn>
Reported-by: Yuxiang Yang <yangyx22@mails.tsinghua.edu.cn>
Reported-by: Ao Wang <wangao@seu.edu.cn>
Reported-by: Xuewei Feng <fengxw06@126.com>
Reported-by: Qi Li <qli01@tsinghua.edu.cn>
Reported-by: Ke Xu <xuke@tsinghua.edu.cn>
Assisted-by: Claude-Code:GLM-5.2
Signed-off-by: Yizhou Zhao <zhaoyz24@mails.tsinghua.edu.cn>
Signed-off-by: Florian Westphal <fw@strlen.de>
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ecache_work_evict_list() redelivers DESTROY events for conntracks that
were moved to the per-netns dying_list after event delivery failed. It
sets a 10ms deadline:
stop = jiffies + ECACHE_MAX_JIFFIES
but then tests:
time_after(stop, jiffies)
This condition is true while the deadline is still in the future, so the
worker returns STATE_RESTART after the first successful redelivery in the
usual case. ecache_work() maps STATE_RESTART to delay 0, which turns the
redelivery path into one dying conntrack per workqueue dispatch and makes
the sent > 16 batching/cond_resched() path effectively unreachable.
A conntrack netlink listener whose receive queue is congested can make
DESTROY event delivery fail with -ENOBUFS. With sustained conntrack
churn, entries then accumulate on the dying_list and are only drained at
the degraded one-entry-per-dispatch rate once delivery succeeds again,
wasting CPU on back-to-back workqueue reschedules and prolonging
conntrack memory/resource pressure.
In a KASAN QEMU test with CONFIG_NF_CONNTRACK_EVENTS=y and
nf_conntrack.enable_hooks=1, a congested DESTROY listener caused 8192
nf_ct_delete() calls to return false and move entries to the dying_list.
After closing the listener, the unfixed kernel needed 7670 ecache_work()
entries to destroy 7669 conntracks. With this change, the same 8192
entries were destroyed by 2 ecache_work() entries.
Swap the comparison so the worker restarts only after the deadline has
expired.
Fixes: 2ed3bf188b33 ("netfilter: ecache: use dedicated list for event redelivery")
Cc: stable@vger.kernel.org
Reported-by: Yizhou Zhao <zhaoyz24@mails.tsinghua.edu.cn>
Reported-by: Yuxiang Yang <yangyx22@mails.tsinghua.edu.cn>
Reported-by: Ao Wang <wangao@seu.edu.cn>
Reported-by: Xuewei Feng <fengxw06@126.com>
Reported-by: Qi Li <qli01@tsinghua.edu.cn>
Reported-by: Ke Xu <xuke@tsinghua.edu.cn>
Assisted-by: Claude-Code:GLM-5.2
Signed-off-by: Yizhou Zhao <zhaoyz24@mails.tsinghua.edu.cn>
Signed-off-by: Florian Westphal <fw@strlen.de>
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xt_nat SNAT and DNAT target handlers assume IP-family conntrack state
is present and can dereference a NULL pointer when instantiated from an
unsupported family through nft_compat. A bridge-family compat rule can
therefore trigger a NULL-dereference in nf_nat_setup_info().
Reject non-IP families in xt_nat_checkentry() so unsupported targets
cannot be installed. Keep NFPROTO_INET allowed for valid inet NAT
compat users and leave the runtime fast path unchanged.
[ The crash was fixed via
9dbba7e694ec ("netfilter: nft_compat: ebtables emulation must reject non-bridge targets"),
so this patch is no longer critical.
Nevertheless, NAT is only relevant for ipv4/ipv6, so this extra
family check is a good idea in any case. ]
Fixes: c7232c9979cb ("netfilter: add protocol independent NAT core")
Cc: stable@vger.kernel.org
Reported-by: Yuan Tan <yuantan098@gmail.com>
Reported-by: Yifan Wu <yifanwucs@gmail.com>
Reported-by: Juefei Pu <tomapufckgml@gmail.com>
Reported-by: Zhengchuan Liang <zcliangcn@gmail.com>
Reported-by: Xin Liu <bird@lzu.edu.cn>
Assisted-by: Codex:GPT-5.4
Signed-off-by: Wyatt Feng <bronzed_45_vested@icloud.com>
Signed-off-by: Ren Wei <n05ec@lzu.edu.cn>
Signed-off-by: Florian Westphal <fw@strlen.de>
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Sashiko points out that after stripping the outer headers
with pskb_pull() we should ensure the inner IP headers
in ICMP errors from tunnels are present in the skb headroom
for functions like ipv4_update_pmtu(), icmp_send() and
IP_VS_DBG().
Also, add more checks for the length of the inner headers.
Fixes: f2edb9f7706d ("ipvs: implement passive PMTUD for IPIP packets")
Link: https://sashiko.dev/#/patchset/20260702073430.67680-1-zhaoyz24%40mails.tsinghua.edu.cn
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Florian Westphal <fw@strlen.de>
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set_sctp_state() reads the SCTP chunk header again in order to drive the
IPVS SCTP state table. For IPv6 it computes the offset with
sizeof(struct ipv6hdr), while the surrounding IPVS code uses iph.len from
ip_vs_fill_iph_skb(), where ipv6_find_hdr() has already skipped
extension headers and found the real transport header.
This makes the state machine read from the wrong offset for IPv6 SCTP
packets that carry extension headers. For example, an INIT packet with an
8-byte destination options header can be scheduled correctly by
sctp_conn_schedule(), but set_sctp_state() reads the first byte of the
SCTP verification tag as a DATA chunk type. The connection then moves
from NONE to ESTABLISHED instead of INIT1, gets the longer established
timeout, and updates the active/inactive destination counters
incorrectly. This happens even though the SCTP handshake has not
completed.
Use the parsed transport offset passed down from ip_vs_set_state() for
the SCTP chunk-header lookup. For IPv4 and IPv6 packets without
extension headers this preserves the existing offset.
Fixes: 2906f66a5682 ("ipvs: SCTP Trasport Loadbalancing Support")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/netdev/20260705123040.35755-1-zhaoyz24@mails.tsinghua.edu.cn/
Reported-by: Yizhou Zhao <zhaoyz24@mails.tsinghua.edu.cn>
Reported-by: Yuxiang Yang <yangyx22@mails.tsinghua.edu.cn>
Reported-by: Ao Wang <wangao@seu.edu.cn>
Reported-by: Xuewei Feng <fengxw06@126.com>
Reported-by: Qi Li <qli01@tsinghua.edu.cn>
Reported-by: Ke Xu <xuke@tsinghua.edu.cn>
Assisted-by: Claude Code:GLM-5.2
Signed-off-by: Yizhou Zhao <zhaoyz24@mails.tsinghua.edu.cn>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Florian Westphal <fw@strlen.de>
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TCP state handling reparses the skb to find the TCP header. For IPv6 it
uses sizeof(struct ipv6hdr), while the surrounding IPVS code already
parsed the packet with ip_vs_fill_iph_skb() and has the real
transport-header offset in iph.len.
This makes TCP state handling look at the wrong bytes when an IPv6
packet carries extension headers. Use the parsed transport offset passed
down from ip_vs_set_state() when reading the TCP header.
For IPv4 and for IPv6 packets without extension headers, the passed
offset matches the previous value.
Fixes: 0bbdd42b7efa6 ("IPVS: Extend protocol DNAT/SNAT and state handlers")
Link: https://lore.kernel.org/netdev/20260705125659.37744-1-zhaoyz24@mails.tsinghua.edu.cn/
Reported-by: Yizhou Zhao <zhaoyz24@mails.tsinghua.edu.cn>
Reported-by: Yuxiang Yang <yangyx22@mails.tsinghua.edu.cn>
Reported-by: Ao Wang <wangao@seu.edu.cn>
Reported-by: Xuewei Feng <fengxw06@126.com>
Reported-by: Qi Li <qli01@tsinghua.edu.cn>
Reported-by: Ke Xu <xuke@tsinghua.edu.cn>
Assisted-by: Claude Code:GLM-5.2
Signed-off-by: Yizhou Zhao <zhaoyz24@mails.tsinghua.edu.cn>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Florian Westphal <fw@strlen.de>
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IPVS callers already parse the packet into struct ip_vs_iphdr before
updating connection state. For IPv6 this records the real
transport-header offset after extension headers in iph.len.
Pass this parsed transport offset through ip_vs_set_state() and the
protocol state_transition() callback so protocol handlers can use the
same packet context as scheduling and NAT handling. This patch only
changes the common callback plumbing and adapts the protocol callback
signatures; TCP and SCTP start using the value in follow-up patches.
Signed-off-by: Yizhou Zhao <zhaoyz24@mails.tsinghua.edu.cn>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Florian Westphal <fw@strlen.de>
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sashiko reports:
When an skb with unreadable fragments (such as from devmem TCP, where
skb_frags_readable(skb) returns false) is processed by the u32 module,
skb_copy_bits() will safely return a negative error code [..]
xt_u32: bail out with hotdrop in this case.
gather_frags: return -1, just as if we had no fragment header.
nfnetlink_queue: restrict to the linear part.
nfnetlink_log: restrict to the linear part.
v2:
- skb_zerocopy helpers don't copy readable flag, i.e. nfnetlink_queue
is broken too
xt_u32 shouldn't return true if hotdrop was set.
Fixes: 65249feb6b3d ("net: add support for skbs with unreadable frags")
Cc: stable@vger.kernel.org
Acked-by: Mina Almasry <almasrymina@google.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
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The combination of IPIP tunnel with direct xmit, eg. bridge device,
breaks because no dst_entry is provided to check the skb headroom and to
set the iph->frag_off field. This leads to invalid dst usage and can
trigger a crash in the tunnel transmit path.
Fix this by moving dst_cache and dst_cookie out of the runtime union so
that they can be shared by neighbour, xfrm, and direct tunnel flows.
For FLOW_OFFLOAD_XMIT_DIRECT tuples carrying tunnel metadata, preserve
route state in these shared fields and release it through the common
dst release path.
Since dst_entry is now available to the three supported xmit modes and
dst_release() already deals with NULL dst, remove the xmit type check
in nft_flow_dst_release(). Moreover, skip the check if the dst entry
is NULL in nf_flow_dst_check() which is now the case for the direct
xmit case.
Based on patch from Rein Wei <n05ec@lzu.edu.cn>.
Fixes: d30301ba4b07 ("netfilter: flowtable: Add IPIP tx sw acceleration")
Cc: stable@vger.kernel.org
Reported-by: Yuan Tan <yuantan098@gmail.com>
Reported-by: Xin Liu <bird@lzu.edu.cn>
Reported-by: Zhengyang Chen <chzhengyang2023@lzu.edu.cn>
Reported-by: Ren Wei <n05ec@lzu.edu.cn>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
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No driver supports for IPIP tunnels yet, give up early on setting up the
hardware offload for this scenario.
This patch adds a stub that can be enhanced to add more configuration
that are currently not supported. As of now, the offload work is
enqueued to the worker, then ignored if the hardware offload
configuration is not supported.
Check the NF_FLOW_HW flag to know if this entry was already tried once
to be offloaded so this is not retried on refresh when unsupported. Move
NF_FLOW_HW flag check to nf_flow_offload_add(). If this NF_FLOW_HW flag
is unset the _del and _stats variants are never called.
This can be updated later on to skip hardware offload work to be queued
in case hardware offload does not support it.
Fixes: d98103575dcd ("netfilter: flowtable: Add IP6IP6 rx sw acceleration")
Fixes: ab427db17885 ("netfilter: flowtable: Add IPIP rx sw acceleration")
Cc: stable@vger.kernel.org
Reported-by: Yuan Tan <yuantan098@gmail.com>
Reported-by: Xin Liu <bird@lzu.edu.cn>
Reported-by: Zhengyang Chen <chzhengyang2023@lzu.edu.cn>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
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When pushing the IPIP header, the route of the other direction is used
to calculate the headroom, use the route in this direction. Accessing
the other tuple to set the IP source and destination is fine because
this tuple does not provide such information to avoid storing redundant
information. However, this tuple already provides the dst for this
direction, this went unnoticed because this bug affects headroom and
iph->frag_off only at this stage.
Fixes: d30301ba4b07 ("netfilter: flowtable: Add IPIP tx sw acceleration")
Fixes: 93cf357fa797 ("netfilter: flowtable: Add IP6IP6 tx sw acceleration")
Cc: stable@vger.kernel.org
Acked-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
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Because a single create function is emitted for every hash type,
from the IPv4 and IPv6 generic hash structure definitions the last
one, i.e. the IPv6 was in effect for IPv4 too. Use the proper size
when allocating the structure. Comment properly that because create()
refers to elements of the generic hash structure, all referred ones
must come before the IPv4/IPv6 dependent 'next' member.
Signed-off-by: Jozsef Kadlecsik <kadlec@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
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Sashiko pointed out that the add/del backlog was not cleaned up
when resize failed. Fix it in the corresponding error path. Also,
make sure that the add/del backlog is htable-specific so when
resize creates a new htable, old/new backlog can't be mixed up.
Signed-off-by: Jozsef Kadlecsik <kadlec@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
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Zhengchuan Liang and Eulgyu Kim reported that because resize
does not copy the comment extension into the resized set but
uses it's pointer, ongoing gc can free the extension in the
original set which then results stale pointer in the resized
one. The proposed patch was to recreate the extensions for
every element in the resized set. It is both expensive and
wastes memory, so better exclude gc when resizing in progress
detected: resizing will destroy the original set anyway,
so doing gc on it is unnecessary.
Introduce a new spinlock to exclude parallel gc and resize.
Because we just set and check a bool value, there's no need
for the parameter to be atomic_t and rename it for better
readability.
Reported-by: Yuan Tan <yuantan098@gmail.com>
Reported-by: Yifan Wu <yifanwucs@gmail.com>
Reported-by: Juefei Pu <tomapufckgml@gmail.com>
Reported-by: Xin Liu <bird@lzu.edu.cn>
Reported by: Zhengchuan Liang <zcliangcn@gmail.com>
Reported by: Eulgyu Kim <eulgyukim@snu.ac.kr>
Signed-off-by: Jozsef Kadlecsik <kadlec@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
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When we bump the uref counter, there's no need to keep
the rcu lock because the referred hash table can't
disappear. Also, from the same reason in mtype_gc we
need the rcu lock and not a spinlock.
Signed-off-by: Jozsef Kadlecsik <kadlec@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
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nft_lookup_eval() decides whether a lookup matched (`found`) from the
direct set lookup and priv->invert before falling back to the
catchall element used by interval sets (e.g. nft_set_rbtree) for the
open-ended default range. Since `found` is never recomputed after
`ext` is replaced by the catchall lookup, inverted lookups
(NFT_LOOKUP_F_INV, "!= @set") can wrongly match or wrongly skip the
catchall element, producing the wrong verdict. Fold the catchall
lookup into `ext` before computing `found`, matching the order
already used by nft_objref_map_eval().
Fixes: aaa31047a6d2 ("netfilter: nftables: add catch-all set element support")
Signed-off-by: Tamaki Yanagawa <ty@000ty.net>
Assisted-by: Claude:claude-sonnet-5
Signed-off-by: Florian Westphal <fw@strlen.de>
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Revision 2 of the CONNMARK target accepts user-controlled shift
parameters and applies them to 32-bit mark values in
connmark_tg_shift().
A shift_bits value of 32 or more triggers an undefined-shift bug when
the rule is evaluated. Invalid shift_dir values are also accepted and
silently fall back to the left-shift path.
Reject invalid revision-2 shift parameters in connmark_tg_check() so
malformed rules fail at installation time, before they can reach the
packet path.
Fixes: 472a73e00757 ("netfilter: xt_conntrack: Support bit-shifting for CONNMARK & MARK targets.")
Reported-by: Yuan Tan <yuantan098@gmail.com>
Reported-by: Zhengchuan Liang <zcliangcn@gmail.com>
Reported-by: Xin Liu <dstsmallbird@foxmail.com>
Assisted-by: Codex:GPT-5.4
Signed-off-by: Wyatt Feng <bronzed_45_vested@icloud.com>
Reviewed-by: Ren Wei <enjou1224z@gmail.com>
Reviewed-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Florian Westphal <fw@strlen.de>
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Commit 9a05475cebdd ("ipvs: avoid kmem_cache_zalloc in
ip_vs_conn_new") changed ip_vs_conn_new() to allocate an ip_vs_conn
object with kmem_cache_alloc(). The function then initializes many
fields explicitly, but only resets in_seq.delta and out_seq.delta in the
two struct ip_vs_seq members.
That leaves init_seq and previous_delta uninitialized. This is normally
harmless while the corresponding IP_VS_CONN_F_IN_SEQ or
IP_VS_CONN_F_OUT_SEQ flag is clear. For connections learned from a sync
message, however, ip_vs_proc_conn() preserves those flags from
IP_VS_CONN_F_BACKUP_MASK and passes opt=NULL when the message omits
IPVS_OPT_SEQ_DATA. In that case the new connection can be hashed with
SEQ flags set but with the rest of in_seq/out_seq still containing stale
slab data.
When a packet for such a connection is later handled by an IPVS
application helper, vs_fix_seq() and vs_fix_ack_seq() use
previous_delta and init_seq to rewrite TCP sequence numbers. A malformed
sync message can therefore make forwarded packets carry stale slab bytes
in their TCP seq/ack numbers, and can also corrupt the forwarded TCP
flow.
Reset both struct ip_vs_seq members completely before publishing the
connection. This matches the existing "reset struct ip_vs_seq" comment
and keeps the sequence-adjustment gates inactive unless valid sequence
data is installed later.
Fixes: 9a05475cebdd ("ipvs: avoid kmem_cache_zalloc in ip_vs_conn_new")
Cc: stable@vger.kernel.org
Reported-by: Yizhou Zhao <zhaoyz24@mails.tsinghua.edu.cn>
Reported-by: Yuxiang Yang <yangyx22@mails.tsinghua.edu.cn>
Reported-by: Ao Wang <wangao@seu.edu.cn>
Reported-by: Xuewei Feng <fengxw06@126.com>
Reported-by: Qi Li <qli01@tsinghua.edu.cn>
Reported-by: Ke Xu <xuke@tsinghua.edu.cn>
Assisted-by: Claude-Code:GLM-5.2
Signed-off-by: Yizhou Zhao <zhaoyz24@mails.tsinghua.edu.cn>
Signed-off-by: Florian Westphal <fw@strlen.de>
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When an ICMP Fragmentation Needed error is received for a tunneled IPVS
connection, ip_vs_in_icmp() recomputes the MTU that the original packet
can use by subtracting the tunnel overhead from the reported next-hop
MTU.
The current code always subtracts sizeof(struct iphdr), which is only
the IPIP overhead. For GUE and GRE tunnels, ipvs_udp_decap() and
ipvs_gre_decap() already compute the additional tunnel header length,
but that value is scoped to the decapsulation block and is lost before
the ICMP_FRAG_NEEDED handling. As a result, the ICMP error sent back to
the client advertises an MTU that is too large, so PMTUD can fail to
converge for GUE/GRE-tunneled real servers.
With a reported next-hop MTU of 1400, a GUE tunnel currently returns
1380 to the client. The correct value is 1368:
1400 - sizeof(struct iphdr) - sizeof(struct udphdr) -
sizeof(struct guehdr)
Hoist the tunnel header length into the main ip_vs_in_icmp() scope and
subtract sizeof(struct iphdr) + ulen in the Fragmentation Needed path.
The IPIP path keeps ulen as 0, so its existing 1400 - 20 = 1380 result
is unchanged.
Fixes: 508f744c0de3 ("ipvs: strip udp tunnel headers from icmp errors")
Cc: stable@vger.kernel.org
Reported-by: Yizhou Zhao <zhaoyz24@mails.tsinghua.edu.cn>
Reported-by: Yuxiang Yang <yangyx22@mails.tsinghua.edu.cn>
Reported-by: Ao Wang <wangao@seu.edu.cn>
Reported-by: Xuewei Feng <fengxw06@126.com>
Reported-by: Qi Li <qli01@tsinghua.edu.cn>
Reported-by: Ke Xu <xuke@tsinghua.edu.cn>
Assisted-by: Claude-Code:GLM-5.2
Signed-off-by: Yizhou Zhao <zhaoyz24@mails.tsinghua.edu.cn>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Florian Westphal <fw@strlen.de>
|
|
The get command on intervals provide partial matches such as subranges
for usability reasons. However, an open interval has no closing end
element. If the closing element matches within the range of the open
internal, ie. its closest match is the start element of the open range,
then, return 0 but offer no matching element to userspace through
netlink as a special case. Userspace provides at least a matching start
element in this case and the closing end element matching the open
interal is ignored.
Another possibility is to report the matching start element of the open
interval for this end interval. However, this results in duplicated
matching being listed in userspace because userspace does not expect a
start element as response to a end element.
Fixes: 2aa34191f06f ("netfilter: nft_set_rbtree: use binary search array in get command")
Reported-by: Melbin K Mathew <mlbnkm1@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
|
|
master on updates
Really cap it to NF_CT_EXPECT_MAX_CNT (255) on updates.
The commit ("netfilter: nfnetlink_cthelper: cap to maximum number of
expectation per master") only covers creation of helpers, not updates.
Fixes: 397c8300972f ("netfilter: nf_conntrack_helper: cap maximum number of expectation at helper registration")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
|
|
On links faster than ~34 Gbps, where byte rate may exceed 2^32-1
(~ 4.3 GBps), the comparison result becomes incorrect because the
truncated value no longer reflects the actual estimator rate.
Fix by changing the local variables to u64.
Fixes: 1c0d32fde5bd ("net_sched: gen_estimator: complete rewrite of rate estimators")
Signed-off-by: Feng Wu <wufengwufengwufeng@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
|
|
u32_match_it() executes rule-supplied shift operands on a 32-bit
value. A malformed u32 rule can provide a shift count of 32 or more,
triggering an undefined shift out-of-bounds during packet evaluation.
Validate XT_U32_LEFTSH and XT_U32_RIGHTSH operands in
u32_mt_checkentry() and reject malformed rules before they reach the
packet path.
Fixes: 1b50b8a371e9 ("[NETFILTER]: Add u32 match")
Reported-by: Yuan Tan <yuantan098@gmail.com>
Reported-by: Yifan Wu <yifanwucs@gmail.com>
Reported-by: Juefei Pu <tomapufckgml@gmail.com>
Reported-by: Zhengchuan Liang <zcliangcn@gmail.com>
Reported-by: Xin Liu <bird@lzu.edu.cn>
Assisted-by: Codex:GPT-5.4
Signed-off-by: Wyatt Feng <bronzed_45_vested@icloud.com>
Signed-off-by: Ren Wei <n05ec@lzu.edu.cn>
Signed-off-by: Florian Westphal <fw@strlen.de>
|
|
quoting sashiko:
------------------------------------------------------------------------
[..] noticed a potential memory bug and header corruption involving the
SIP NAT helper.
In net/netfilter/nf_nat_sip.c:nf_nat_sip():
if (skb_ensure_writable(skb, skb->len)) {
nf_ct_helper_log(skb, ct, "cannot mangle packet");
return NF_DROP;
}
uh = (void *)skb->data + protoff;
uh->dest = ct_sip_info->forced_dport;
if (!nf_nat_mangle_udp_packet(skb, ct, ctinfo, protoff,
0, 0, NULL, 0)) {
If a cloned or fragmented SKB is reallocated by skb_ensure_writable(), the
old data buffer is freed. However, nf_nat_sip() fails to update *dptr to
point to the new buffer.
It also appears to use nf_nat_mangle_udp_packet() on what could be a TCP
packet, which would overwrite the sequence number with a checksum update.
------------------------------------------------------------------------
nf_conntrack_sip linerizes skbs, hence no fragmented skb can be seen.
But clones are possible, so rebuild dptr.
Disable nf_nat_mangle_udp_packet() branch for TCP streams.
It doesn't look like this can ever happen, else we should have received
bug reports about this, so just check the conntrack is UDP and drop
otherwise.
The calling conntrack_sip set ->forced_dport for SIP_HDR_VIA_UDP messages,
so I don't think this is ever expected to be true for a TCP stream.
Fixes: 7266507d8999 ("netfilter: nf_ct_sip: support Cisco 7941/7945 IP phones")
Cc: stable@vger.kernel.org
Assisted-by: Claude:claude-sonnet-4-6
Signed-off-by: Florian Westphal <fw@strlen.de>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Pull networking fixes from Paolo Abeni:
"Including fixes from netfilter and batman-adv.
Current release - new code bugs:
- netfilter: cthelper: cap to maximum number of expectation per master
Previous releases - regressions:
- netpoll: fix a use-after-free on shutdown path
- tcp: restore RCU grace period in tcp_ao_destroy_sock
- ipv6: fix NULL deref in fib6_walk_continiue() on multi-batch dump
- batman-adv: dat: ensure accessible eth_hdr proto field
- eth:
- virtio_net: disable cb when NAPI is busy-polled
- lan743x: Initialize eth_syslock spinlock before use
Previous releases - always broken:
- netfilter:
- nft_set_pipapo: don't leak bad clone into future transaction
- sched:
- sch_teql: Introduce slaves_lock to avoid race condition and UAF
- replace direct dequeue call with peek and qdisc_dequeue_peeked
- sctp: add INIT verification after cookie unpacking
- tipc: fix out-of-bounds read in broadcast Gap ACK blocks
- seg6: validate SRH length before reading fixed fields
- eth:
- mlx5e: fix use-after-free of metadata_dst on RX SC delete
- enetc: check the number of BDs needed for xdp_frame
- fbnic: don't cache shinfo across skb realloc"
* tag 'net-7.2-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (58 commits)
net/mlx5: HWS, fix matcher leak on resize target setup failure
net/sched: hhf: clear heavy-hitter state on reset
net/sched: dualpi2: clear stale classification on filter miss
net/sched: act_bpf: use rcu_dereference_bh() to read the filter
selftests: drv-net: tso: don't touch dangerous feature bits
cxgb4: Fix decode strings dump for T6 adapters
virtio_net: disable cb when NAPI is busy-polled
sctp: fix addr_wq_timer race in sctp_free_addr_wq()
selftests: net: bump default cmd() timeout to 20 seconds
bridge: stp: Fix a potential use-after-free when deleting a bridge
net/sched: sch_teql: Introduce slaves_lock to avoid race condition and UAF
net: gianfar: dispose irq mappings on probe failure and device removal
net: lan743x: Initialize eth_syslock spinlock before use
net: libwx: fix VMDQ mask for 1-queue mode
net: airoha: fix max receive size configuration
fsl/fman: Free init resources on KeyGen failure in fman_init()
netfilter: nftables: restrict checkum update offset
netfilter: nftables: restrict linklayer and network header writes
netfilter: nfnetlink_queue: restrict writes to network header
netfilter: nft_fib: reject fib expression on the netdev egress hook
...
|
|
After previous patch, writes to network header are restricted.
However, there is another way to manipulate the l3 header: The
checksum update function.
Restrict this for network header writes, only the ipv4 header is
allowed. This needs run-time checks because BRIDGE, INET, NETDEV
families can carry l3 headers other than IP.
checksum updates to the udp/tcp (l4) headers are not restricted.
Signed-off-by: Florian Westphal <fw@strlen.de>
|
|
Don't permit arbitrary writes to linklayer and network header data.
Several spots in network stack trust header validation performed in
ipv4/ipv6 before PRE_ROUTING hook.
For linklayer, allow writes for netdev ingress. For other hooks, only
allow link layer writes that do not spill into network header.
For network header, check the offset/length combinations:
- changing dscp requires store at offset 0 for checsum fixups, so
make sure ip version + length field isn't altered.
- ip6 dscp starts directly after the version field, so make sure it
remains 6.
Several of these checks could already be done at rule insertion time.
Risk is that this might cause ruleset load failures for existing
rulesets. With this change such writes are silently skipped and packet
passes unchanged.
Transport and inner header bases are not checked / restricted.
Signed-off-by: Florian Westphal <fw@strlen.de>
|
|
nfnetlink_queue doesn't allow selective replacements of some part of the
payload, only complete replacement.
If the new data is shorter, skb is trimmed, otherwise expanded.
Add minimal validation of the new ip/ipv6 header. Check total len
matches skb length. Disallow ip option modifications.
IPv6 extension headers are also disabled.
IP options and exthdrs could be allowed later after validation pass or
ip option recompile.
Transport header is not checked.
Bridge modifications are rejected. Given userspace doesn't even receive
L2 headers, use is limited and I don't think there are any users of
bridge nfnetlink_queue, let alone users that modifiy payload.
Arp isn't supported at all.
Signed-off-by: Florian Westphal <fw@strlen.de>
|
|
A fib expression in a netdev egress base chain dereferences nft_in(pkt),
NULL on the transmit path, causing a NULL pointer dereference at eval.
nft_fib_validate() masks the hook with NF_INET_* values, but netdev hook
numbers are a separate enum that aliases them (NF_NETDEV_EGRESS ==
NF_INET_LOCAL_IN), so an egress chain passes validation and then faults.
Add nft_fib_netdev_validate() that limits each result/flag to the netdev
hook where the device it reads exists: the input-device cases (OIF,
OIFNAME, ADDRTYPE with F_IIF) to ingress, the output-device case (ADDRTYPE
with F_OIF) to egress, ADDRTYPE with no device flag to both. Also restrict
nft_fib_validate() to NFPROTO_IPV4/IPV6/INET so its NF_INET_* masks are
not applied to another family's hooks.
Fixes: 42df6e1d221d ("netfilter: Introduce egress hook")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/netfilter-devel/ajxsjcDOnwllMfoR@strlen.de/
Signed-off-by: Theodor Arsenij Larionov-Trichkine <theodorlarionov@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
|
|
If userspace helper policy updates sets maximum number of expectation to
zero, cap it to NF_CT_EXPECT_MAX_CNT (255) on updates too.
Fixes: 397c8300972f ("netfilter: nf_conntrack_helper: cap maximum number of expectation at helper registration")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
|
|
tc ingress and openvswitch do not guarantee routing information to be
available. These subsystems use the conntrack helper infrastructure, and
the SIP helper relies on the skb_dst() to be present if
sip_external_media is set to 1 (which is disabled by default as a module
parameter).
This effectively disables the sip_external_media toggle for these
subsystems without resulting in a crash.
Fixes: cae3a2627520 ("openvswitch: Allow attaching helpers to ct action")
Fixes: b57dc7c13ea9 ("net/sched: Introduce action ct")
Cc: stable@vger.kernel.org
Reported-by: Ren Wei <n05ec@lzu.edu.cn>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
|
|
The release path of ip_set_dump_do() and ip_set_dump_done() read
inst->ip_set_list via ip_set_ref_netlink(), a plain rcu_dereference_raw()
of the array pointer. These run from netlink_recvmsg() without the nfnl
mutex and without an RCU read-side critical section.
A concurrent ip_set_create() can grow the array: it publishes the new
array, calls synchronize_net() and then kvfree()s the old one. Since the
dump paths read the array outside any RCU reader, synchronize_net() does
not wait for them and the old array can be freed while they still index
into it, causing a use-after-free.
The dumped set itself stays pinned via set->ref_netlink, so only the
array load needs protecting. Take rcu_read_lock() around it, matching
ip_set_get_byname() and __ip_set_put_byindex().
BUG: KASAN: slab-use-after-free in ip_set_dump_do (net/netfilter/ipset/ip_set_core.c:1697)
Read of size 8 at addr ffff88800b5c4018 by task exploit/150
Call Trace:
...
kasan_report (mm/kasan/report.c:595)
ip_set_dump_do (net/netfilter/ipset/ip_set_core.c:1697)
netlink_dump (net/netlink/af_netlink.c:2325)
netlink_recvmsg (net/netlink/af_netlink.c:1976)
sock_recvmsg (net/socket.c:1159)
__sys_recvfrom (net/socket.c:2315)
...
Oops: general protection fault, probably for non-canonical address ... KASAN NOPTI
KASAN: maybe wild-memory-access in range [0x02d6...d0-0x02d6...d7]
RIP: 0010:ip_set_dump_do (net/netfilter/ipset/ip_set_core.c:1698)
Kernel panic - not syncing: Fatal exception
Fixes: 8a02bdd50b2e ("netfilter: ipset: Fix calling ip_set() macro at dumping")
Cc: stable@vger.kernel.org
Reported-by: Weiming Shi <bestswngs@gmail.com>
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Xiang Mei <xmei5@asu.edu>
Acked-by: Jozsef Kadlecsik <kadlec@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
|
|
On memory allocation failure the cloned nft_pipapo_match can enter a bad
state:
- some fields can have their lookup tables resized while others did
not
- bits might have been toggled
- scratch map can be undersized which also means m->bsize_max can be
lower than what is required
This means that the next insertion in the same batch can trigger
out-of-bounds writes.
Furthermore, a failure in the first can result in the bad clone to
leak into the next transaction because the abort callback is never
executed in this case (the upper layer saw an error and no attempt to
allocate a transactional request was made).
Record a state for the nft_pipapo_match structure:
- NEW (pristine clone)
- MOD (modified clone with good state)
- ERR (potentially bogus content)
Then make it so that deletes and insertions fail when the clone
entered ERR state.
In case the very first insert attempt results in an error, free the
clone right away.
Fixes: 3c4287f62044 ("nf_tables: Add set type for arbitrary concatenation of ranges")
Cc: stable@vger.kernel.org
Reported-and-tested-by: Seesee <cjc000013@gmail.com>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
|
|
There are occasional LLM hints wrt. leaking uninitialized data to
userspace via ctnetlink. Just zero at allocation time,
expectations are not frequently used these days.
Intentionally keeps _init as-is because we could theoretically
support re-init, so add the missing exp->dir there.
Signed-off-by: Florian Westphal <fw@strlen.de>
|
|
Pull bpf fixes from Alexei Starovoitov:
- Fix effective prog array index with BPF_F_PREORDER (Amery Hung)
- Zero-initialize the fib lookup flow struct (Avinash Duduskar)
- Disable xfrm_decode_session hook attachment (Bradley Morgan)
- Allow type tag BTF records to succeed other modifier records (Emil
Tsalapatis)
- Fix build_id caching in stack_map_get_build_id_offset() (Ihor
Solodrai)
- Add missing access_ok call to copy_user_syms (Jiri Olsa)
- Fix stack slot index in nospec checks (Nuoqi Gui)
- Preserve pointer spill metadata during half-slot cleanup (Nuoqi Gui)
- Fix partial copy of non-linear test_run output (Sun Jian)
- Fix BPF_PROG_ASSOC_STRUCT_OPS last field check (Thiébaud Weksteen)
- Reset register bounds before narrowing retval range (Tristan Madani)
- Fix vmlinux BTF leak in bpftool cgroup commands (Yichong Chen)
- Guard error writes in conntrack kfuncs (Yiyang Chen)
* tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
bpf: Disable xfrm_decode_session hook attachment
selftests/bpf: Add test for stale bounds on LSM retval context load
bpf: Reset register bounds before narrowing retval range in check_mem_access()
selftests/bpf: Cover small conntrack opts error writes
bpf: Guard conntrack opts error writes
selftests/bpf: Cover half-slot cleanup of pointer spills
bpf: Preserve pointer spill metadata during half-slot cleanup
selftests/bpf: Test cgroup link replace with BPF_F_PREORDER
bpf: Fix effective prog array index with BPF_F_PREORDER
bpf: Fix BPF_PROG_ASSOC_STRUCT_OPS last field check
bpf: zero-initialize the fib lookup flow struct
bpftool: Fix vmlinux BTF leak in cgroup commands
bpf: Add missing access_ok call to copy_user_syms
bpf: Allow type tag BTF records to succeed other modifier records
bpf: Emit verbose message when prog-specific btf_struct_access rejects a write
bpf: Fix build_id caching in stack_map_get_build_id_offset()
bpf: Fix partial copy of non-linear test_run output
selftests/bpf: Cover stack nospec slot indexing
bpf: Fix stack slot index in nospec checks
|
|
registration
On helper registration, the maximum number of expectations cannot go over
NF_CT_EXPECT_MAX_CNT (255), but zero can be specified then
nf_conntrack_expect_max applies. Turn zero into NF_CT_EXPECT_MAX_CNT
otherwise, expectation LRU eviction on insertion is disabled.
Moreover, expand this sanity check all expectation classes.
This max_expecy policy is only tunable since userspace helpers are
available, set Fixes: tag to the commit that adds such infrastructure.
Remove the check for p->max_expected given this field must always
be non-zero after this patch.
Fixes: 12f7a505331e ("netfilter: add user-space connection tracking helper infrastructure")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
|
|
Userspace passes '5000' in case user asks for 5 seconds.
Allowing for sub-second expectation lifetimes makes sense to me. so
fix up the kernel side instead of munging nft to send a value rounded
up to next second.
Also note that this violates nft convention of passing integers in
network byte order, but we can't change this anymore.
Fixes: 857b46027d6f ("netfilter: nft_ct: add ct expectations support")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
|
|
Run expectation eviction if no helper is specified to deal with the
nft_ct expectation support.
Cap the maximum expectation limit per master conntrack to
NF_CT_EXPECT_MAX_CNT (255).
Fixes: 857b46027d6f ("netfilter: nft_ct: add ct expectations support")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
|
|
Store master conntrack tuple in the expectation since exp->master might
refer to a different conntrack when accessed from rcu read side lock
area due to typesafe rcu rules.
Fixes: 02a3231b6d82 ("netfilter: nf_conntrack_expect: store netns and zone in expectation")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
|
|
IRC Direct client-to-client requires plaintext. IRC over TLS should be
preferred, making this helper ineffective. Add a deprecation warning and
update the help text to better reflect that this is needed for the DCC
extension, not IRC itself.
PPTP is esoteric these days and it is the only helper that requires the
destroy callback in the conntrack helper API.
Removal would simplify the conntrack core.
Both helpers are IPv4 only.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
|
|
This feature allows to reset a helper for an existing conntrack, but it
is not safe. This requires a synchronized_rcu() call after resetting the
helper, which is going to be expensive for a large batch of conntrack
entries. This also needs to call to the .destroy callback to release the
GRE/PPTP mappings to fix it.
This feature antedates the creation of the conntrack-tools and I cannot
find a good use-case for this. Given that I cannot find any user in the
netfilter.org userspace tree, I prefer to remove this feature.
Fixes: c1d10adb4a52 ("[NETFILTER]: Add ctnetlink port for nf_conntrack")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
|
|
xtables targets return netfilter verdicts: NF_ACCEPT, NF_DROP, and so
on. ebtables targets return incompatible verdicts: EBT_ACCEPT,
EBT_DROP, ... We cannot allow fallback to NFPROTO_UNSPEC.
ebtables doesn't permit this since
11ff7288beb2 ("netfilter: ebtables: reject non-bridge targets")
but that commit missed the nft_compat layer.
Reported-by: Ren Wei <n05ec@lzu.edu.cn>
Reported-by: Wyatt Feng <bronzed_45_vested@icloud.com>
Reported-by: Yuan Tan <yuantan098@gmail.com>
Reported-by: Yifan Wu <yifanwucs@gmail.com>
Reported-by: Juefei Pu <tomapufckgml@gmail.com>
Reported-by: Zhengchuan Liang <zcliangcn@gmail.com>
Reported-by: Xin Liu <bird@lzu.edu.cn>
Fixes: 0ca743a55991 ("netfilter: nf_tables: add compatibility layer for x_tables")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
|
|
nft_synproxy_eval_v4() and nft_synproxy_eval_v6() already take a
whole-object READ_ONCE() snapshot of the shared priv->info state before
building the SYNACK reply, but nft_synproxy_tcp_options() still masks
opts->options with priv->info.options from the live shared object.
When a named synproxy object is updated concurrently with SYN traffic,
the eval path can then mix mss and timestamp handling from the local
snapshot with an options mask taken from a newer configuration, so one
SYNACK no longer reflects a coherent synproxy configuration.
Use info->options so nft_synproxy_tcp_options() stays on the same local
snapshot that the eval path already copied from priv->info.
Fixes: ee394f96ad75 ("netfilter: nft_synproxy: add synproxy stateful object support")
Signed-off-by: Runyu Xiao <runyu.xiao@seu.edu.cn>
Reviewed-by: Fernando Fernandez Mancera <fmancera@suse.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
|
|
Add sanity check for iph->ihl field in nf_flow_ip4_tunnel_proto() before
using it to compute the header size, avoiding out-of-bounds access with
malformed IP headers.
While at it, use iph->protocol instead of the hardcoded IPPROTO_IPIP
constant when setting ctx->tun.proto and reference ctx->tun.hdr_size
when updating ctx->offset.
Fixes: ab427db178858 ("netfilter: flowtable: Add IPIP rx sw acceleration")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
|
|
Commit 69894e5b4c5e ("netfilter: nft_connlimit: update the count if add
was skipped") introduced a regression where packets for valid
connections are dropped when using connlimit for soft-limiting
scenarios.
The issue occurs when a new connection reuses a socket currently in
the TIME_WAIT state. In this scenario, the connection tracking entry
is evaluated as already confirmed. Previously, __nf_conncount_add()
assumed that if a connection was confirmed and did not originate from
the loopback interface, it should skip the addition and return -EEXIST.
Skipping the addition triggers a garbage collection run that cleans up
the TIME_WAIT connection. Consequently, the active connection count
drops to 0, which xt_connlimit mishandles, leading to the false rejection
of the perfectly valid new connection.
Fix this by replacing the interface check with protocol-agnostic state
checks. We now skip the tree insertion and preserve the lockless garbage
collection optimization only if the connection is IPS_ASSURED. This
allows early-confirmed setup packets (such as reused TIME_WAIT sockets
or locally generated SYN-ACKs) to be properly evaluated and counted
without falsely dropping. The goto check_connections path is maintained
to ensure these setup packets are deduplicated correctly.
This has been tested with slowhttptest and HTTP server configured
locally to ensure we are not breaking soft-limiting scenarios for local
or external connections. In addition, it was tested with a OVS zone
limit too.
Fixes: 69894e5b4c5e ("netfilter: nft_connlimit: update the count if add was skipped")
Reported-by: Alejandro Olivan Alvarez <alejandro.olivan.alvarez@gmail.com>
Closes: https://lore.kernel.org/netfilter-devel/177349610461.3071718.4083978280323144323@eldamar.lan/
Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
|
|
We ran into below KASAN splat, which is mostly uninteresting, beside
for having nf_nat_register_fn() in the call chain as a cause for the
offending access:
==================================================================
BUG: KASAN: slab-out-of-bounds in nf_nat_register_fn+0x5f9/0x640
Read of size 8 at addr ffff890031e54c20 by task iptables/9510
CPU: 0 UID: 0 PID: 9510 Comm: iptables Not tainted 6.18.18-grsec-full-20260320181326 #1 PREEMPT(voluntary)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
<TASK>
[…] dump_stack_lvl+0xee/0x160 ffff88004117eeb8
[…] print_report+0x6e/0x640 ffff88004117eee0
[…] ? __phys_addr+0x8e/0x140 ffff88004117eef0
[…] ? kasan_addr_to_slab+0x51/0xe0 ffff88004117ef08
[…] ? complete_report_info+0xec/0x1c0 ffff88004117ef20
[…] ? nf_nat_register_fn+0x5f9/0x640 ffff88004117ef48
[…] kasan_report+0xbc/0x140 ffff88004117ef50
[…] ? nf_nat_register_fn+0x5f9/0x640 ffff88004117ef90
[…] nf_nat_register_fn+0x5f9/0x640 ffff88004117eff8
[…] ? nf_nat_icmp_reply_translation+0x6e0/0x6e0 ffff88004117f070
[…] nf_tables_register_hook.part.0+0xa0/0x220 ffff88004117f080
[…] nf_tables_addchain.constprop.0+0x1054/0x1fc0 ffff88004117f0b8
[…] ? nft_chain_lookup.part.0+0x4ce/0xac0 ffff88004117f130
[…] ? nf_tables_abort+0x3d80/0x3d80 ffff88004117f190
[…] ? nf_tables_dumpreset_obj+0x100/0x100 ffff88004117f1c8
[…] ? nft_table_lookup.part.0+0x255/0x300 ffff88004117f310
[…] ? nf_tables_newchain+0x21a4/0x2fa0 ffff88004117f358
[…] nf_tables_newchain+0x21a4/0x2fa0 ffff88004117f360
[…] ? nf_tables_addchain.constprop.0+0x1fc0/0x1fc0 ffff88004117f458
[…] ? nla_get_range_signed+0x4a0/0x4a0 ffff88004117f488
[…] ? lock_acquire+0x16f/0x320 ffff88004117f490
[…] ? find_held_lock+0x3b/0xe0 ffff88004117f4b0
[…] ? __nla_parse+0x45/0x80 ffff88004117f500
[…] nfnetlink_rcv_batch+0xbca/0x19a0 ffff88004117f550
[…] ? nfnetlink_net_exit_batch+0x120/0x120 ffff88004117f618
[…] ? __sanitizer_cov_trace_switch+0x63/0xe0 ffff88004117f720
[…] ? gr_acl_handle_mmap+0x1c4/0x320 ffff88004117f7c0
[…] ? nla_get_range_signed+0x4a0/0x4a0 ffff88004117f7e8
[…] ? gr_is_capable+0x6f/0xe0 ffff88004117f830
[…] ? __nla_parse+0x45/0x80 ffff88004117f860
[…] ? skb_pull+0x103/0x1a0 ffff88004117f880
[…] nfnetlink_rcv+0x3db/0x4a0 ffff88004117f8b0
[…] ? nfnetlink_rcv_batch+0x19a0/0x19a0 ffff88004117f8d8
[…] ? netlink_lookup+0xe2/0x240 ffff88004117f900
[…] netlink_unicast+0x74b/0xb00 ffff88004117f930
[…] ? netlink_attachskb+0xb20/0xb20 ffff88004117f980
[…] ? __check_object_size+0x3e/0xaa0 ffff88004117f998
[…] ? security_netlink_send+0x51/0x160 ffff88004117f9c8
[…] netlink_sendmsg+0xa03/0x1200 ffff88004117f9f8
[…] ? netlink_unicast+0xb00/0xb00 ffff88004117fa70
[…] ? netlink_unicast+0xb00/0xb00 ffff88004117fac8
[…] ? ____sys_sendmsg+0xe2a/0x1040 ffff88004117faf8
[…] ____sys_sendmsg+0xe2a/0x1040 ffff88004117fb00
[…] ? kernel_recvmsg+0x300/0x300 ffff88004117fb60
[…] ? reacquire_held_locks+0xe9/0x260 ffff88004117fbc8
[…] ___sys_sendmsg+0x138/0x200 ffff88004117fbf8
[…] ? do_recvmmsg+0x7e0/0x7e0 ffff88004117fc30
[…] ? lockdep_hardirqs_on_prepare+0x101/0x1e0 ffff88004117fc50
[…] ? lock_acquire+0x16f/0x320 ffff88004117fd20
[…] ? lock_acquire+0x16f/0x320 ffff88004117fd58
[…] ? find_held_lock+0x3b/0xe0 ffff88004117fd70
[…] __sys_sendmsg+0x17a/0x260 ffff88004117fdc8
[…] ? __sys_sendmsg_sock+0x80/0x80 ffff88004117fdf0
[…] ? syscall_trace_enter+0x15e/0x2c0 ffff88004117fe98
[…] do_syscall_64+0x7d/0x400 ffff88004117fec8
[…] entry_SYSCALL_64_safe_stack+0x4a/0x60 ffff88004117fef8
</TASK>
==================================================================
The out-of-bounds report, though, is a red herring as it is for an
access that shouldn't have happened in the first place.
When nf_nat_init() fails to register its BPF kfuncs, it'll unwind and,
among others, call unregister_pernet_subsys() to deregister its per-net
ops. This makes the previously allocated net id available for reuse by
the next caller of register_pernet_subsys(), in our case, synproxy.
However, 'nat_net_id' will still hold the previously allocated value.
If nf_nat.o gets build as a module, all this doesn't matter. A failed
initialization routine makes the module fail to load and any dependent
module won't be able to load either. However, if nf_nat.o is built-in,
a failing init won't /completely/ make its functionality unavailable to
dependent modules, namely the code and static data is still there, free
to be called by modules like nft_chain_nat.ko.
Case in point, nft_chain_nat registers hooks that'll call into nf_nat
which, in our case, failed to initialize and therefore won't have a
valid net id nor related net_nat object any more.
Code in nf_nat, namely nf_nat_register_fn() and nf_nat_unregister_fn(),
still making use of the reallocated net id, lead to a type confusion as
the call to net_generic() will no longer return memory belonging to an
object suited to fit 'struct nat_net' but 'struct synproxy_net' instead.
The latter is only 24 bytes on 64-bit systems, much smaller than struct
nat_net which is 176 bytes, perfectly explaining the OOB KASAN report.
Detect and handle a failed nf_nat_init() by testing the 'nf_nat_hook'
pointer which will be reset to NULL on initialization errors to prevent
the usage of an invalid nat_net pointer.
As this check is only needed when nf_nat.o is built-in, guard it by
'#ifndef MODULE...'.
Fixes: cbc1dd5b659f ("netfilter: nf_nat: Fix possible memory leak in nf_nat_init()")
Signed-off-by: Mathias Krause <minipli@grsecurity.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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