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9 daysnetfilter: nft_set_pipapo: split gc into unlink and reclaim phaseFlorian Westphal-0/+5
Yiming Qian reports Use-after-free in the pipapo set type: Under a large number of expired elements, commit-time GC can run for a very long time in a non-preemptible context, triggering soft lockup warnings and RCU stall reports (local denial of service). We must split GC in an unlink and a reclaim phase. We cannot queue elements for freeing until pointers have been swapped. Expired elements are still exposed to both the packet path and userspace dumpers via the live copy of the data structure. call_rcu() does not protect us: dump operations or element lookups starting after call_rcu has fired can still observe the free'd element, unless the commit phase has made enough progress to swap the clone and live pointers before any new reader has picked up the old version. This a similar approach as done recently for the rbtree backend in commit 35f83a75529a ("netfilter: nft_set_rbtree: don't gc elements on insert"). Fixes: 3c4287f62044 ("nf_tables: Add set type for arbitrary concatenation of ranges") Reported-by: Yiming Qian <yimingqian591@gmail.com> Signed-off-by: Florian Westphal <fw@strlen.de>
9 daysnetfilter: nf_tables: clone set on flush onlyPablo Neira Ayuso-0/+2
Syzbot with fault injection triggered a failing memory allocation with GFP_KERNEL which results in a WARN splat: iter.err WARNING: net/netfilter/nf_tables_api.c:845 at nft_map_deactivate+0x34e/0x3c0 net/netfilter/nf_tables_api.c:845, CPU#0: syz.0.17/5992 Modules linked in: CPU: 0 UID: 0 PID: 5992 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:nft_map_deactivate+0x34e/0x3c0 net/netfilter/nf_tables_api.c:845 Code: 8b 05 86 5a 4e 09 48 3b 84 24 a0 00 00 00 75 62 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc e8 63 6d fa f7 90 <0f> 0b 90 43 +80 7c 35 00 00 0f 85 23 fe ff ff e9 26 fe ff ff 89 d9 RSP: 0018:ffffc900045af780 EFLAGS: 00010293 RAX: ffffffff89ca45bd RBX: 00000000fffffff4 RCX: ffff888028111e40 RDX: 0000000000000000 RSI: 00000000fffffff4 RDI: 0000000000000000 RBP: ffffc900045af870 R08: 0000000000400dc0 R09: 00000000ffffffff R10: dffffc0000000000 R11: fffffbfff1d141db R12: ffffc900045af7e0 R13: 1ffff920008b5f24 R14: dffffc0000000000 R15: ffffc900045af920 FS: 000055557a6a5500(0000) GS:ffff888125496000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb5ea271fc0 CR3: 000000003269e000 CR4: 00000000003526f0 Call Trace: <TASK> __nft_release_table+0xceb/0x11f0 net/netfilter/nf_tables_api.c:12115 nft_rcv_nl_event+0xc25/0xdb0 net/netfilter/nf_tables_api.c:12187 notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85 blocking_notifier_call_chain+0x6a/0x90 kernel/notifier.c:380 netlink_release+0x123b/0x1ad0 net/netlink/af_netlink.c:761 __sock_release net/socket.c:662 [inline] sock_close+0xc3/0x240 net/socket.c:1455 Restrict set clone to the flush set command in the preparation phase. Add NFT_ITER_UPDATE_CLONE and use it for this purpose, update the rbtree and pipapo backends to only clone the set when this iteration type is used. As for the existing NFT_ITER_UPDATE type, update the pipapo backend to use the existing set clone if available, otherwise use the existing set representation. After this update, there is no need to clone a set that is being deleted, this includes bound anonymous set. An alternative approach to NFT_ITER_UPDATE_CLONE is to add a .clone interface and call it from the flush set path. Reported-by: syzbot+4924a0edc148e8b4b342@syzkaller.appspotmail.com Fixes: 3f1d886cc7c3 ("netfilter: nft_set_pipapo: move cloning of match info to insert/removal path") Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Florian Westphal <fw@strlen.de>
2026-02-10Merge tag 'nf-next-26-02-06' of ↵Jakub Kicinski-0/+5
https://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf-next Florian Westphal says: ==================== netfilter: updates for net-next The following patchset contains Netfilter updates for *net-next*: 1) Fix net-next-only use-after-free bug in nf_tables rbtree set: Expired elements cannot be released right away after unlink anymore because there is no guarantee that the binary-search blob is going to be updated. Spotted by syzkaller. 2) Fix esoteric bug in nf_queue with udp fraglist gro, broken since 6.11. Patch 3 adds extends the nfqueue selftest for this. 4) Use dedicated slab for flowtable entries, currently the -512 cache is used, which is wasteful. From Qingfang Deng. 5) Recent net-next update extended existing test for ip6ip6 tunnels, add the required /config entry. Test still passed by accident because the previous tests network setup gets re-used, so also update the test so it will fail in case the ip6ip6 tunnel interface cannot be added. 6) Fix 'nft get element mytable myset { 1.2.3.4 }' on big endian platforms, this was broken since code was added in v5.1. 7) Fix nf_tables counter reset support on 32bit platforms, where counter reset may cause huge values to appear due to wraparound. Broken since reset feature was added in v6.11. From Anders Grahn. 8-11) update nf_tables rbtree set type to detect partial operlaps. This will eventually speed up nftables userspace: at this time userspace does a netlink dump of the set content which slows down incremental updates on interval sets. From Pablo Neira Ayuso. * tag 'nf-next-26-02-06' of https://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf-next: netfilter: nft_set_rbtree: validate open interval overlap netfilter: nft_set_rbtree: validate element belonging to interval netfilter: nft_set_rbtree: check for partial overlaps in anonymous sets netfilter: nft_set_rbtree: fix bogus EEXIST with NLM_F_CREATE with null interval netfilter: nft_counter: fix reset of counters on 32bit archs netfilter: nft_set_hash: fix get operation on big endian selftests: netfilter: add IPV6_TUNNEL to config netfilter: flowtable: dedicated slab for flow entry selftests: netfilter: nft_queue.sh: add udp fraglist gro test case netfilter: nfnetlink_queue: do shared-unconfirmed check before segmentation netfilter: nft_set_rbtree: don't gc elements on insert ==================== Link: https://patch.msgid.link/20260206153048.17570-1-fw@strlen.de Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-02-06net/ipv6: Introduce payload_len helpersAlice Mikityanska-2/+2
The next commits will transition away from using the hop-by-hop extension header to encode packet length for BIG TCP. Add wrappers around ip6->payload_len that return the actual value if it's non-zero, and calculate it from skb->len if payload_len is set to zero (and a symmetrical setter). The new helpers are used wherever the surrounding code supports the hop-by-hop jumbo header for BIG TCP IPv6, or the corresponding IPv4 code uses skb_ip_totlen (e.g., in include/net/netfilter/nf_tables_ipv6.h). No behavioral change in this commit. Signed-off-by: Alice Mikityanska <alice@isovalent.com> Acked-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20260205133925.526371-2-alice.kernel@fastmail.im Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-02-06netfilter: nft_set_rbtree: validate open interval overlapPablo Neira Ayuso-0/+4
Open intervals do not have an end element, in particular an open interval at the end of the set is hard to validate because of it is lacking the end element, and interval validation relies on such end element to perform the checks. This patch adds a new flag field to struct nft_set_elem, this is not an issue because this is a temporary object that is allocated in the stack from the insert/deactivate path. This flag field is used to specify that this is the last element in this add/delete command. The last flag is used, in combination with the start element cookie, to check if there is a partial overlap, eg. Already exists: 255.255.255.0-255.255.255.254 Add interval: 255.255.255.0-255.255.255.255 ~~~~~~~~~~~~~ start element overlap Basically, the idea is to check for an existing end element in the set if there is an overlap with an existing start element. However, the last open interval can come in any position in the add command, the corner case can get a bit more complicated: Already exists: 255.255.255.0-255.255.255.254 Add intervals: 255.255.255.0-255.255.255.255,255.255.255.0-255.255.255.254 ~~~~~~~~~~~~~ start element overlap To catch this overlap, annotate that the new start element is a possible overlap, then report the overlap if the next element is another start element that confirms that previous element in an open interval at the end of the set. For deletions, do not update the start cookie when deleting an open interval, otherwise this can trigger spurious EEXIST when adding new elements. Unfortunately, there is no NFT_SET_ELEM_INTERVAL_OPEN flag which would make easier to detect open interval overlaps. Fixes: 7c84d41416d8 ("netfilter: nft_set_rbtree: Detect partial overlaps on insertion") Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Florian Westphal <fw@strlen.de>
2026-02-06netfilter: nfnetlink_queue: do shared-unconfirmed check before segmentationFlorian Westphal-0/+1
Ulrich reports a regression with nfqueue: If an application did not set the 'F_GSO' capability flag and a gso packet with an unconfirmed nf_conn entry is received all packets are now dropped instead of queued, because the check happens after skb_gso_segment(). In that case, we did have exclusive ownership of the skb and its associated conntrack entry. The elevated use count is due to skb_clone happening via skb_gso_segment(). Move the check so that its peformed vs. the aggregated packet. Then, annotate the individual segments except the first one so we can do a 2nd check at reinject time. For the normal case, where userspace does in-order reinjects, this avoids packet drops: first reinjected segment continues traversal and confirms entry, remaining segments observe the confirmed entry. While at it, simplify nf_ct_drop_unconfirmed(): We only care about unconfirmed entries with a refcnt > 1, there is no need to special-case dying entries. This only happens with UDP. With TCP, the only unconfirmed packet will be the TCP SYN, those aren't aggregated by GRO. Next patch adds a udpgro test case to cover this scenario. Reported-by: Ulrich Weber <ulrich.weber@gmail.com> Fixes: 7d8dc1c7be8d ("netfilter: nf_queue: drop packets with cloned unconfirmed conntracks") Signed-off-by: Florian Westphal <fw@strlen.de>
2026-01-29netfilter: nfnetlink_queue: optimize verdict lookup with hash tableScott Mitchell-0/+3
The current implementation uses a linear list to find queued packets by ID when processing verdicts from userspace. With large queue depths and out-of-order verdicting, this O(n) lookup becomes a significant bottleneck, causing userspace verdict processing to dominate CPU time. Replace the linear search with a hash table for O(1) average-case packet lookup by ID. A global rhashtable spanning all network namespaces attributes hash bucket memory to kernel but is subject to fixed upper bound. Signed-off-by: Scott Mitchell <scott.k.mitch1@gmail.com> Signed-off-by: Florian Westphal <fw@strlen.de>
2026-01-22netfilter: nf_tables: add .abort_skip_removal flag for set typesPablo Neira Ayuso-0/+2
The pipapo set backend is the only user of the .abort interface so far. To speed up pipapo abort path, removals are skipped. The follow up patch updates the rbtree to use to build an array of ordered elements, then use binary search. This needs a new .abort interface but, unlike pipapo, it also need to undo/remove elements. Add a flag and use it from the pipapo set backend. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Florian Westphal <fw@strlen.de>
2026-01-20netfilter: nf_conntrack: don't rely on implicit includesFlorian Westphal-0/+1
several netfilter compilation units rely on implicit includes coming from nf_conntrack_proto_gre.h. Clean this up and add the required dependencies where needed. nf_conntrack.h requires net_generic() helper. Place various gre/ppp/vlan includes to where they are needed. Signed-off-by: Florian Westphal <fw@strlen.de>
2026-01-20netfilter: don't include xt and nftables.h in unrelated subsystemsFlorian Westphal-2/+1
conntrack, xtables and nftables are distinct subsystems, don't use them in other subystems. Signed-off-by: Florian Westphal <fw@strlen.de>
2026-01-20netfilter: nf_conncount: increase the connection clean up limit to 64Fernando Fernandez Mancera-0/+1
After the optimization to only perform one GC per jiffy, a new problem was introduced. If more than 8 new connections are tracked per jiffy the list won't be cleaned up fast enough possibly reaching the limit wrongly. In order to prevent this issue, only skip the GC if it was already triggered during the same jiffy and the increment is lower than the clean up limit. In addition, increase the clean up limit to 64 connections to avoid triggering GC too often and do more effective GCs. This has been tested using a HTTP server and several performance tools while having nft_connlimit/xt_connlimit or OVS limit configured. Output of slowhttptest + OVS limit at 52000 connections: slow HTTP test status on 340th second: initializing: 0 pending: 432 connected: 51998 error: 0 closed: 0 service available: YES Fixes: d265929930e2 ("netfilter: nf_conncount: reduce unnecessary GC") Reported-by: Aleksandra Rukomoinikova <ARukomoinikova@k2.cloud> Closes: https://lore.kernel.org/netfilter/b2064e7b-0776-4e14-adb6-c68080987471@k2.cloud/ Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de> Signed-off-by: Florian Westphal <fw@strlen.de>
2025-12-15netfilter: nf_tables: avoid chain re-validation if possibleFlorian Westphal-8/+26
Hamza Mahfooz reports cpu soft lock-ups in nft_chain_validate(): watchdog: BUG: soft lockup - CPU#1 stuck for 27s! [iptables-nft-re:37547] [..] RIP: 0010:nft_chain_validate+0xcb/0x110 [nf_tables] [..] nft_immediate_validate+0x36/0x50 [nf_tables] nft_chain_validate+0xc9/0x110 [nf_tables] nft_immediate_validate+0x36/0x50 [nf_tables] nft_chain_validate+0xc9/0x110 [nf_tables] nft_immediate_validate+0x36/0x50 [nf_tables] nft_chain_validate+0xc9/0x110 [nf_tables] nft_immediate_validate+0x36/0x50 [nf_tables] nft_chain_validate+0xc9/0x110 [nf_tables] nft_immediate_validate+0x36/0x50 [nf_tables] nft_chain_validate+0xc9/0x110 [nf_tables] nft_immediate_validate+0x36/0x50 [nf_tables] nft_chain_validate+0xc9/0x110 [nf_tables] nft_table_validate+0x6b/0xb0 [nf_tables] nf_tables_validate+0x8b/0xa0 [nf_tables] nf_tables_commit+0x1df/0x1eb0 [nf_tables] [..] Currently nf_tables will traverse the entire table (chain graph), starting from the entry points (base chains), exploring all possible paths (chain jumps). But there are cases where we could avoid revalidation. Consider: 1 input -> j2 -> j3 2 input -> j2 -> j3 3 input -> j1 -> j2 -> j3 Then the second rule does not need to revalidate j2, and, by extension j3, because this was already checked during validation of the first rule. We need to validate it only for rule 3. This is needed because chain loop detection also ensures we do not exceed the jump stack: Just because we know that j2 is cycle free, its last jump might now exceed the allowed stack size. We also need to update all reachable chains with the new largest observed call depth. Care has to be taken to revalidate even if the chain depth won't be an issue: chain validation also ensures that expressions are not called from invalid base chains. For example, the masquerade expression can only be called from NAT postrouting base chains. Therefore we also need to keep record of the base chain context (type, hooknum) and revalidate if the chain becomes reachable from a different hook location. Reported-by: Hamza Mahfooz <hamzamahfooz@linux.microsoft.com> Closes: https://lore.kernel.org/netfilter-devel/20251118221735.GA5477@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net/ Tested-by: Hamza Mahfooz <hamzamahfooz@linux.microsoft.com> Signed-off-by: Florian Westphal <fw@strlen.de>
2025-11-28netfilter: nf_conncount: rework API to use sk_buff directlyFernando Fernandez Mancera-9/+8
When using nf_conncount infrastructure for non-confirmed connections a duplicated track is possible due to an optimization introduced since commit d265929930e2 ("netfilter: nf_conncount: reduce unnecessary GC"). In order to fix this introduce a new conncount API that receives directly an sk_buff struct. It fetches the tuple and zone and the corresponding ct from it. It comes with both existing conncount variants nf_conncount_count_skb() and nf_conncount_add_skb(). In addition remove the old API and adjust all the users to use the new one. This way, for each sk_buff struct it is possible to check if there is a ct present and already confirmed. If so, skip the add operation. Fixes: d265929930e2 ("netfilter: nf_conncount: reduce unnecessary GC") Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2025-11-28netfilter: flowtable: Add IPIP rx sw accelerationLorenzo Bianconi-0/+18
Introduce sw acceleration for rx path of IPIP tunnels relying on the netfilter flowtable infrastructure. Subsequent patches will add sw acceleration for IPIP tunnels tx path. This series introduces basic infrastructure to accelerate other tunnel types (e.g. IP6IP6). IPIP rx sw acceleration can be tested running the following scenario where the traffic is forwarded between two NICs (eth0 and eth1) and an IPIP tunnel is used to access a remote site (using eth1 as the underlay device): ETH0 -- TUN0 <==> ETH1 -- [IP network] -- TUN1 (192.168.100.2) $ip addr show 6: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000 link/ether 00:00:22:33:11:55 brd ff:ff:ff:ff:ff:ff inet 192.168.0.2/24 scope global eth0 valid_lft forever preferred_lft forever 7: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000 link/ether 00:11:22:33:11:55 brd ff:ff:ff:ff:ff:ff inet 192.168.1.1/24 scope global eth1 valid_lft forever preferred_lft forever 8: tun0@NONE: <POINTOPOINT,NOARP,UP,LOWER_UP> mtu 1480 qdisc noqueue state UNKNOWN group default qlen 1000 link/ipip 192.168.1.1 peer 192.168.1.2 inet 192.168.100.1/24 scope global tun0 valid_lft forever preferred_lft forever $ip route show default via 192.168.100.2 dev tun0 192.168.0.0/24 dev eth0 proto kernel scope link src 192.168.0.2 192.168.1.0/24 dev eth1 proto kernel scope link src 192.168.1.1 192.168.100.0/24 dev tun0 proto kernel scope link src 192.168.100.1 $nft list ruleset table inet filter { flowtable ft { hook ingress priority filter devices = { eth0, eth1 } } chain forward { type filter hook forward priority filter; policy accept; meta l4proto { tcp, udp } flow add @ft } } Reproducing the scenario described above using veths I got the following results: - TCP stream received from the IPIP tunnel: - net-next: (baseline) ~ 71Gbps - net-next + IPIP flowtbale support: ~101Gbps Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2025-11-28netfilter: flowtable: remove hw_ifidxPablo Neira Ayuso-1/+0
hw_ifidx was originally introduced to store the real netdevice as a requirement for the hardware offload support in: 73f97025a972 ("netfilter: nft_flow_offload: use direct xmit if hardware offload is enabled") Since ("netfilter: flowtable: consolidate xmit path"), ifidx and hw_ifidx points to the real device in the xmit path, remove it. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2025-11-27netfilter: flowtable: consolidate xmit pathPablo Neira Ayuso-0/+1
Use dev_queue_xmit() for the XMIT_NEIGH case. Store the interface index of the real device behind the vlan/pppoe device, this introduces an extra lookup for the real device in the xmit path because rt->dst.dev provides the vlan/pppoe device. XMIT_NEIGH now looks more similar to XMIT_DIRECT but the check for stale dst and the neighbour lookup still remain in place which is convenient to deal with network topology changes. Note that nft_flow_route() needs to relax the check for _XMIT_NEIGH so the existing basic xfrm offload (which only works in one direction) does not break. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2025-11-27netfilter: flowtable: move path discovery infrastructure to its own filePablo Neira Ayuso-0/+6
This file contains the path discovery that is run from the forward chain for the packet offloading the flow into the flowtable. This consists of a series of calls to dev_fill_forward_path() for each device stack. More topologies may be supported in the future, so move this code to its own file to separate it from the nftables flow_offload expression. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2025-10-30netfilter: fix typo in nf_conntrack_l4proto.h commentcaivive (Weibiao Tu)-1/+1
In the comment for nf_conntrack_l4proto.h, the word "nfnetink" was incorrectly spelled. It has been corrected to "nfnetlink". Fixes a typo to enhance readability and ensure consistency. Signed-off-by: caivive (Weibiao Tu) <cavivie@gmail.com> Signed-off-by: Florian Westphal <fw@strlen.de>
2025-09-11Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski-9/+2
Cross-merge networking fixes after downstream PR (net-6.17-rc6). Conflicts: net/netfilter/nft_set_pipapo.c net/netfilter/nft_set_pipapo_avx2.c c4eaca2e1052 ("netfilter: nft_set_pipapo: don't check genbit from packetpath lookups") 84c1da7b38d9 ("netfilter: nft_set_pipapo: use avx2 algorithm for insertions too") Only trivial adjacent changes (in a doc and a Makefile). Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-10netfilter: nf_tables: make nft_set_do_lookup available unconditionallyFlorian Westphal-8/+2
This function was added for retpoline mitigation and is replaced by a static inline helper if mitigations are not enabled. Enable this helper function unconditionally so next patch can add a lookup restart mechanism to fix possible false negatives while transactions are in progress. Adding lookup restarts in nft_lookup_eval doesn't work as nft_objref would then need the same copypaste loop. This patch is separate to ease review of the actual bug fix. Suggested-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Florian Westphal <fw@strlen.de>
2025-09-10netfilter: nf_tables: place base_seq in struct netFlorian Westphal-1/+0
This will soon be read from packet path around same time as the gencursor. Both gencursor and base_seq get incremented almost at the same time, so it makes sense to place them in the same structure. This doesn't increase struct net size on 64bit due to padding. Signed-off-by: Florian Westphal <fw@strlen.de>
2025-09-02netfilter: nft_payload: extend offset to 65535 bytesFernando Fernandez Mancera-1/+1
In some situations 255 bytes offset is not enough to match or manipulate the desired packet field. Increase the offset limit to 65535 or U16_MAX. In addition, the nla policy maximum value is not set anymore as it is limited to s16. Instead, the maximum value is checked during the payload expression initialization function. Tested with the nft command line tool. table ip filter { chain output { @nh,2040,8 set 0xff @nh,524280,8 set 0xff @nh,524280,8 0xff @nh,2040,8 0xff } } Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de> Signed-off-by: Florian Westphal <fw@strlen.de>
2025-09-02netfilter: nf_reject: remove unneeded exportsFlorian Westphal-18/+0
These functions have no external callers and can be static. Signed-off-by: Florian Westphal <fw@strlen.de>
2025-09-02netfilter: nf_tables: allow iter callbacks to sleepFlorian Westphal-0/+2
Quoting Sven Auhagen: we do see on occasions that we get the following error message, more so on x86 systems than on arm64: Error: Could not process rule: Cannot allocate memory delete table inet filter It is not a consistent error and does not happen all the time. We are on Kernel 6.6.80, seems to me like we have something along the lines of the nf_tables: allow clone callbacks to sleep problem using GFP_ATOMIC. As hinted at by Sven, this is because of GFP_ATOMIC allocations during set flush. When set is flushed, all elements are deactivated. This triggers a set walk and each element gets added to the transaction list. The rbtree and rhashtable sets don't allow the iter callback to sleep: rbtree walk acquires read side of an rwlock with bh disabled, rhashtable walk happens with rcu read lock held. Rbtree is simple enough to resolve: When the walk context is ITER_READ, no change is needed (the iter callback must not deactivate elements; we're not in a transaction). When the iter type is ITER_UPDATE, the rwlock isn't needed because the caller holds the transaction mutex, this prevents any and all changes to the ruleset, including add/remove of set elements. Rhashtable is slightly more complex. When the iter type is ITER_READ, no change is needed, like rbtree. For ITER_UPDATE, we hold transaction mutex which prevents elements from getting free'd, even outside of rcu read lock section. So build a temporary list of all elements while doing the rcu iteration and then call the iterator in a second pass. The disadvantage is the need to iterate twice, but this cost comes with the benefit to allow the iter callback to use GFP_KERNEL allocations in a followup patch. The new list based logic makes it necessary to catch recursive calls to the same set earlier. Such walk -> iter -> walk recursion for the same set can happen during ruleset validation in case userspace gave us a bogus (cyclic) ruleset where verdict map m jumps to chain that sooner or later also calls "vmap @m". Before the new ->in_update_walk test, the ruleset is rejected because the infinite recursion causes ctx->level to exceed the allowed maximum. But with the new logic added here, elements would get skipped: nft_rhash_walk_update would see elements that are on the walk_list of an older stack frame. As all recursive calls into same map results in -EMLINK, we can avoid this problem by using the new in_update_walk flag and reject immediately. Next patch converts the problematic GFP_ATOMIC allocations. Reported-by: Sven Auhagen <Sven.Auhagen@belden.com> Closes: https://lore.kernel.org/netfilter-devel/BY1PR18MB5874110CAFF1ED098D0BC4E7E07BA@BY1PR18MB5874.namprd18.prod.outlook.com/ Signed-off-by: Florian Westphal <fw@strlen.de>
2025-07-25netfilter: nft_set: remove indirection from update API callFlorian Westphal-4/+3
This stems from a time when sets and nft_dynset resided in different kernel modules. We can replace this with a direct call. We could even remove both ->update and ->delete, given its only supported by rhashtable, but on the off-chance we'll see runtime add/delete for other types or a new set type keep that as-is for now. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2025-07-25netfilter: nft_set: remove one argument from lookup and update functionsFlorian Westphal-26/+31
Return the extension pointer instead of passing it as a function argument to be filled in by the callee. As-is, whenever false is returned, the extension pointer is not used. For all set types, when true is returned, the extension pointer was set to the matching element. Only exception: nft_set_bitmap doesn't support extensions. Return a pointer to a static const empty element extension container. return false -> return NULL return true -> return the elements' extension pointer. This saves one function argument. Signed-off-by: Florian Westphal <fw@strlen.de> Reviewed-by: Stefano Brivio <sbrivio@redhat.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2025-07-25netfilter: nf_tables: Remove unused nft_reduce_is_readonly()Yue Haibing-5/+0
Since commit 9e539c5b6d9c ("netfilter: nf_tables: disable expression reduction infra") this is unused. Signed-off-by: Yue Haibing <yuehaibing@huawei.com> Reviewed-by: Simon Horman <horms@kernel.org> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2025-07-25netfilter: load nf_log_syslog on enabling nf_conntrack_log_invalidLance Yang-0/+3
When no logger is registered, nf_conntrack_log_invalid fails to log invalid packets, leaving users unaware of actual invalid traffic. Improve this by loading nf_log_syslog, similar to how 'iptables -I FORWARD 1 -m conntrack --ctstate INVALID -j LOG' triggers it. Suggested-by: Florian Westphal <fw@strlen.de> Signed-off-by: Zi Li <zi.li@linux.dev> Signed-off-by: Lance Yang <lance.yang@linux.dev> Acked-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2025-07-17Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski-7/+13
Cross-merge networking fixes after downstream PR (net-6.16-rc7). Conflicts: Documentation/netlink/specs/ovpn.yaml 880d43ca9aa4 ("netlink: specs: clean up spaces in brackets") af52020fc599 ("ovpn: reject unexpected netlink attributes") drivers/net/phy/phy_device.c a44312d58e78 ("net: phy: Don't register LEDs for genphy") f0f2b992d818 ("net: phy: Don't register LEDs for genphy") https://lore.kernel.org/20250710114926.7ec3a64f@kernel.org drivers/net/wireless/intel/iwlwifi/fw/regulatory.c drivers/net/wireless/intel/iwlwifi/mld/regulatory.c 5fde0fcbd760 ("wifi: iwlwifi: mask reserved bits in chan_state_active_bitmap") ea045a0de3b9 ("wifi: iwlwifi: add support for accepting raw DSM tables by firmware") net/ipv6/mcast.c ae3264a25a46 ("ipv6: mcast: Delay put pmc->idev in mld_del_delrec()") a8594c956cc9 ("ipv6: mcast: Avoid a duplicate pointer check in mld_del_delrec()") https://lore.kernel.org/8cc52891-3653-4b03-a45e-05464fe495cf@kernel.org No adjacent changes. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-07-17netfilter: nf_conntrack: fix crash due to removal of uninitialised entryFlorian Westphal-2/+13
A crash in conntrack was reported while trying to unlink the conntrack entry from the hash bucket list: [exception RIP: __nf_ct_delete_from_lists+172] [..] #7 [ff539b5a2b043aa0] nf_ct_delete at ffffffffc124d421 [nf_conntrack] #8 [ff539b5a2b043ad0] nf_ct_gc_expired at ffffffffc124d999 [nf_conntrack] #9 [ff539b5a2b043ae0] __nf_conntrack_find_get at ffffffffc124efbc [nf_conntrack] [..] The nf_conn struct is marked as allocated from slab but appears to be in a partially initialised state: ct hlist pointer is garbage; looks like the ct hash value (hence crash). ct->status is equal to IPS_CONFIRMED|IPS_DYING, which is expected ct->timeout is 30000 (=30s), which is unexpected. Everything else looks like normal udp conntrack entry. If we ignore ct->status and pretend its 0, the entry matches those that are newly allocated but not yet inserted into the hash: - ct hlist pointers are overloaded and store/cache the raw tuple hash - ct->timeout matches the relative time expected for a new udp flow rather than the absolute 'jiffies' value. If it were not for the presence of IPS_CONFIRMED, __nf_conntrack_find_get() would have skipped the entry. Theory is that we did hit following race: cpu x cpu y cpu z found entry E found entry E E is expired <preemption> nf_ct_delete() return E to rcu slab init_conntrack E is re-inited, ct->status set to 0 reply tuplehash hnnode.pprev stores hash value. cpu y found E right before it was deleted on cpu x. E is now re-inited on cpu z. cpu y was preempted before checking for expiry and/or confirm bit. ->refcnt set to 1 E now owned by skb ->timeout set to 30000 If cpu y were to resume now, it would observe E as expired but would skip E due to missing CONFIRMED bit. nf_conntrack_confirm gets called sets: ct->status |= CONFIRMED This is wrong: E is not yet added to hashtable. cpu y resumes, it observes E as expired but CONFIRMED: <resumes> nf_ct_expired() -> yes (ct->timeout is 30s) confirmed bit set. cpu y will try to delete E from the hashtable: nf_ct_delete() -> set DYING bit __nf_ct_delete_from_lists Even this scenario doesn't guarantee a crash: cpu z still holds the table bucket lock(s) so y blocks: wait for spinlock held by z CONFIRMED is set but there is no guarantee ct will be added to hash: "chaintoolong" or "clash resolution" logic both skip the insert step. reply hnnode.pprev still stores the hash value. unlocks spinlock return NF_DROP <unblocks, then crashes on hlist_nulls_del_rcu pprev> In case CPU z does insert the entry into the hashtable, cpu y will unlink E again right away but no crash occurs. Without 'cpu y' race, 'garbage' hlist is of no consequence: ct refcnt remains at 1, eventually skb will be free'd and E gets destroyed via: nf_conntrack_put -> nf_conntrack_destroy -> nf_ct_destroy. To resolve this, move the IPS_CONFIRMED assignment after the table insertion but before the unlock. Pablo points out that the confirm-bit-store could be reordered to happen before hlist add resp. the timeout fixup, so switch to set_bit and before_atomic memory barrier to prevent this. It doesn't matter if other CPUs can observe a newly inserted entry right before the CONFIRMED bit was set: Such event cannot be distinguished from above "E is the old incarnation" case: the entry will be skipped. Also change nf_ct_should_gc() to first check the confirmed bit. The gc sequence is: 1. Check if entry has expired, if not skip to next entry 2. Obtain a reference to the expired entry. 3. Call nf_ct_should_gc() to double-check step 1. nf_ct_should_gc() is thus called only for entries that already failed an expiry check. After this patch, once the confirmed bit check passes ct->timeout has been altered to reflect the absolute 'best before' date instead of a relative time. Step 3 will therefore not remove the entry. Without this change to nf_ct_should_gc() we could still get this sequence: 1. Check if entry has expired. 2. Obtain a reference. 3. Call nf_ct_should_gc() to double-check step 1: 4 - entry is still observed as expired 5 - meanwhile, ct->timeout is corrected to absolute value on other CPU and confirm bit gets set 6 - confirm bit is seen 7 - valid entry is removed again First do check 6), then 4) so the gc expiry check always picks up either confirmed bit unset (entry gets skipped) or expiry re-check failure for re-inited conntrack objects. This change cannot be backported to releases before 5.19. Without commit 8a75a2c17410 ("netfilter: conntrack: remove unconfirmed list") |= IPS_CONFIRMED line cannot be moved without further changes. Cc: Razvan Cojocaru <rzvncj@gmail.com> Link: https://lore.kernel.org/netfilter-devel/20250627142758.25664-1-fw@strlen.de/ Link: https://lore.kernel.org/netfilter-devel/4239da15-83ff-4ca4-939d-faef283471bb@gmail.com/ Fixes: 1397af5bfd7d ("netfilter: conntrack: remove the percpu dying list") Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2025-07-14Revert "netfilter: nf_tables: Add notifications for hook changes"Phil Sutter-5/+0
This reverts commit 465b9ee0ee7bc268d7f261356afd6c4262e48d82. Such notifications fit better into core or nfnetlink_hook code, following the NFNL_MSG_HOOK_GET message format. Signed-off-by: Phil Sutter <phil@nwl.cc> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2025-07-11Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski-1/+1
Cross-merge networking fixes after downstream PR (net-6.16-rc6-2). No conflicts. Adjacent changes: drivers/net/wireless/mediatek/mt76/mt7925/mcu.c c701574c5412 ("wifi: mt76: mt7925: fix invalid array index in ssid assignment during hw scan") b3a431fe2e39 ("wifi: mt76: mt7925: fix off by one in mt7925_mcu_hw_scan()") drivers/net/wireless/mediatek/mt76/mt7996/mac.c 62da647a2b20 ("wifi: mt76: mt7996: Add MLO support to mt7996_tx_check_aggr()") dc66a129adf1 ("wifi: mt76: add a wrapper for wcid access with validation") drivers/net/wireless/mediatek/mt76/mt7996/main.c 3dd6f67c669c ("wifi: mt76: Move RCU section in mt7996_mcu_add_rate_ctrl()") 8989d8e90f5f ("wifi: mt76: mt7996: Do not set wcid.sta to 1 in mt7996_mac_sta_event()") net/mac80211/cfg.c 58fcb1b4287c ("wifi: mac80211: reject VHT opmode for unsupported channel widths") 037dc18ac3fb ("wifi: mac80211: add support for storing station S1G capabilities") Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-07-10netfilter: flowtable: account for Ethernet header in nf_flow_pppoe_proto()Eric Dumazet-1/+1
syzbot found a potential access to uninit-value in nf_flow_pppoe_proto() Blamed commit forgot the Ethernet header. BUG: KMSAN: uninit-value in nf_flow_offload_inet_hook+0x7e4/0x940 net/netfilter/nf_flow_table_inet.c:27 nf_flow_offload_inet_hook+0x7e4/0x940 net/netfilter/nf_flow_table_inet.c:27 nf_hook_entry_hookfn include/linux/netfilter.h:157 [inline] nf_hook_slow+0xe1/0x3d0 net/netfilter/core.c:623 nf_hook_ingress include/linux/netfilter_netdev.h:34 [inline] nf_ingress net/core/dev.c:5742 [inline] __netif_receive_skb_core+0x4aff/0x70c0 net/core/dev.c:5837 __netif_receive_skb_one_core net/core/dev.c:5975 [inline] __netif_receive_skb+0xcc/0xac0 net/core/dev.c:6090 netif_receive_skb_internal net/core/dev.c:6176 [inline] netif_receive_skb+0x57/0x630 net/core/dev.c:6235 tun_rx_batched+0x1df/0x980 drivers/net/tun.c:1485 tun_get_user+0x4ee0/0x6b40 drivers/net/tun.c:1938 tun_chr_write_iter+0x3e9/0x5c0 drivers/net/tun.c:1984 new_sync_write fs/read_write.c:593 [inline] vfs_write+0xb4b/0x1580 fs/read_write.c:686 ksys_write fs/read_write.c:738 [inline] __do_sys_write fs/read_write.c:749 [inline] Reported-by: syzbot+bf6ed459397e307c3ad2@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/686bc073.a00a0220.c7b3.0086.GAE@google.com/T/#u Fixes: 87b3593bed18 ("netfilter: flowtable: validate pppoe header") Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Pablo Neira Ayuso <pablo@netfilter.org> Link: https://patch.msgid.link/20250707124517.614489-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-07-03netfilter: conntrack: remove DCCP protocol supportPablo Neira Ayuso-19/+0
The DCCP socket family has now been removed from this tree, see: 8bb3212be4b4 ("Merge branch 'net-retire-dccp-socket'") Remove connection tracking and NAT support for this protocol, this should not pose a problem because no DCCP traffic is expected to be seen on the wire. As for the code for matching on dccp header for iptables and nftables, mark it as deprecated and keep it in place. Ruleset restoration is an atomic operation. Without dccp matching support, an astray match on dccp could break this operation leaving your computer with no policy in place, so let's follow a more conservative approach for matches. Add CONFIG_NFT_EXTHDR_DCCP which is set to 'n' by default to deprecate dccp extension support. Similarly, label CONFIG_NETFILTER_XT_MATCH_DCCP as deprecated too and also set it to 'n' by default. Code to match on DCCP protocol from ebtables also remains in place, this is just a few checks on IPPROTO_DCCP from _check() path which is exercised when ruleset is loaded. There is another use of IPPROTO_DCCP from the _check() path in the iptables multiport match. Another check for IPPROTO_DCCP from the packet in the reject target is also removed. So let's schedule removal of the dccp matching for a second stage, this should not interfer with the dccp retirement since this is only matching on the dccp header. Cc: "David S. Miller" <davem@davemloft.net> Cc: Eric Dumazet <edumazet@google.com> Cc: Jakub Kicinski <kuba@kernel.org> Cc: Paolo Abeni <pabeni@redhat.com> Cc: Kuniyuki Iwashima <kuniyu@amazon.com> Reviewed-by: Simon Horman <horms@kernel.org> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2025-05-23netfilter: nf_tables: Add notifications for hook changesPhil Sutter-0/+5
Notify user space if netdev hooks are updated due to netdev add/remove events. Send minimal notification messages by introducing NFT_MSG_NEWDEV/DELDEV message types describing a single device only. Upon NETDEV_CHANGENAME, the callback has no information about the interface's old name. To provide a clear message to user space, include the hook's stored interface name in the notification. Signed-off-by: Phil Sutter <phil@nwl.cc> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2025-05-23netfilter: nf_tables: Have a list of nf_hook_ops in nft_hookPhil Sutter-1/+1
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>
2025-05-23netfilter: nf_tables: Introduce nft_hook_find_ops{,_rcu}()Phil Sutter-0/+5
Also a pretty dull wrapper around the hook->ops.dev comparison for now. Will search the embedded nf_hook_ops list in future. The ugly cast to eliminate the const qualifier will vanish then, too. Since this future list will be RCU-protected, also introduce an _rcu() variant here. Signed-off-by: Phil Sutter <phil@nwl.cc> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2025-05-23netfilter: nf_tables: nft_fib: consistent l3mdev handlingFlorian Westphal-0/+9
fib has two modes: 1. Obtain output device according to source or destination address 2. Obtain the type of the address, e.g. local, unicast, multicast. 'fib daddr type' should return 'local' if the address is configured in this netns or unicast otherwise. 'fib daddr . iif type' should return 'local' if the address is configured on the input interface or unicast otherwise, i.e. more restrictive. However, if the interface is part of a VRF, then 'fib daddr type' returns unicast even if the address is configured on the incoming interface. This is broken for both ipv4 and ipv6. In the ipv4 case, inet_dev_addr_type must only be used if the 'iif' or 'oif' (strict mode) was requested. Else inet_addr_type_dev_table() needs to be used and the correct dev argument must be passed as well so the correct fib (vrf) table is used. In the ipv6 case, the bug is similar, without strict mode, dev is NULL so .flowi6_l3mdev will be set to 0. Add a new 'nft_fib_l3mdev_master_ifindex_rcu()' helper and use that to init the .l3mdev structure member. For ipv6, use it from nft_fib6_flowi_init() which gets called from both the 'type' and the 'route' mode eval functions. This provides consistent behaviour for all modes for both ipv4 and ipv6: If strict matching is requested, the input respectively output device of the netfilter hooks is used. Otherwise, use skb->dev to obtain the l3mdev ifindex. Without this, most type checks in updated nft_fib.sh selftest fail: FAIL: did not find veth0 . 10.9.9.1 . local in fibtype4 FAIL: did not find veth0 . dead:1::1 . local in fibtype6 FAIL: did not find veth0 . dead:9::1 . local in fibtype6 FAIL: did not find tvrf . 10.0.1.1 . local in fibtype4 FAIL: did not find tvrf . 10.9.9.1 . local in fibtype4 FAIL: did not find tvrf . dead:1::1 . local in fibtype6 FAIL: did not find tvrf . dead:9::1 . local in fibtype6 FAIL: fib expression address types match (iif in vrf) (fib errounously returns 'unicast' for all of them, even though all of these addresses are local to the vrf). Fixes: f6d0cbcf09c5 ("netfilter: nf_tables: add fib expression") Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2025-03-25Merge tag 'nf-next-25-03-23' of ↵Jakub Kicinski-0/+21
git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf-next Pablo Neira Ayuso says: ==================== Netfilter updates for net-next The following batch contains Netfilter updates for net-next: 1) Use kvmalloc in xt_hashlimit, from Denis Kirjanov. 2) Tighten nf_conntrack sysctl accepted values for nf_conntrack_max and nf_ct_expect_max, from Nicolas Bouchinet. 3) Avoid lookup in nft_fib if socket is available, from Florian Westphal. 4) Initialize struct lsm_context in nfnetlink_queue to avoid hypothetical ENOMEM errors, Chenyuan Yang. 5) Use strscpy() instead of _pad when initializing xtables table name, kzalloc is already used to initialized the table memory area. From Thorsten Blum. 6) Missing socket lookup by conntrack information for IPv6 traffic in nft_socket, there is a similar chunk in IPv4, this was never added when IPv6 NAT was introduced. From Maxim Mikityanskiy. 7) Fix clang issues with nf_tables CONFIG_MITIGATION_RETPOLINE, from WangYuli. * tag 'nf-next-25-03-23' of git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf-next: netfilter: nf_tables: Only use nf_skip_indirect_calls() when MITIGATION_RETPOLINE netfilter: socket: Lookup orig tuple for IPv6 SNAT netfilter: xtables: Use strscpy() instead of strscpy_pad() netfilter: nfnetlink_queue: Initialize ctx to avoid memory allocation error netfilter: fib: avoid lookup if socket is available netfilter: conntrack: Bound nf_conntrack sysctl writes netfilter: xt_hashlimit: replace vmalloc calls with kvmalloc ==================== Link: https://patch.msgid.link/20250323100922.59983-1-pablo@netfilter.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-03-21netfilter: fib: avoid lookup if socket is availableFlorian Westphal-0/+21
In case the fib match is used from the input hook we can avoid the fib lookup if early demux assigned a socket for us: check that the input interface matches sk-cached one. Rework the existing 'lo bypass' logic to first check sk, then for loopback interface type to elide the fib lookup. This speeds up fib matching a little, before: 93.08 GBit/s (no rules at all) 75.1 GBit/s ("fib saddr . iif oif missing drop" in prerouting) 75.62 GBit/s ("fib saddr . iif oif missing drop" in input) After: 92.48 GBit/s (no rules at all) 75.62 GBit/s (fib rule in prerouting) 90.37 GBit/s (fib rule in input). Numbers for the 'no rules' and 'prerouting' are expected to closely match in-between runs, the 3rd/input test case exercises the the 'avoid lookup if cached ifindex in sk matches' case. Test used iperf3 via veth interface, lo can't be used due to existing loopback test. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2025-03-06netfilter: nf_tables: make destruction work queue pernetFlorian Westphal-1/+3
The call to flush_work before tearing down a table from the netlink notifier was supposed to make sure that all earlier updates (e.g. rule add) that might reference that table have been processed. Unfortunately, flush_work() waits for the last queued instance. This could be an instance that is different from the one that we must wait for. This is because transactions are protected with a pernet mutex, but the work item is global, so holding the transaction mutex doesn't prevent another netns from queueing more work. Make the work item pernet so that flush_work() will wait for all transactions queued from this netns. A welcome side effect is that we no longer need to wait for transaction objects from foreign netns. The gc work queue is still global. This seems to be ok because nft_set structures are reference counted and each container structure owns a reference on the net namespace. The destroy_list is still protected by a global spinlock rather than pernet one but the hold time is very short anyway. v2: call cancel_work_sync before reaping the remaining tables (Pablo). Fixes: 9f6958ba2e90 ("netfilter: nf_tables: unconditionally flush pending work before notifier") Reported-by: syzbot+5d8c5789c8cb076b2c25@syzkaller.appspotmail.com Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2025-01-19netfilter: flowtable: add CLOSING statePablo Neira Ayuso-0/+1
tcp rst/fin packet triggers an immediate teardown of the flow which results in sending flows back to the classic forwarding path. This behaviour was introduced by: da5984e51063 ("netfilter: nf_flow_table: add support for sending flows back to the slow path") b6f27d322a0a ("netfilter: nf_flow_table: tear down TCP flows if RST or FIN was seen") whose goal is to expedite removal of flow entries from the hardware table. Before these patches, the flow was released after the flow entry timed out. However, this approach leads to packet races when restoring the conntrack state as well as late flow re-offload situations when the TCP connection is ending. This patch adds a new CLOSING state that is is entered when tcp rst/fin packet is seen. This allows for an early removal of the flow entry from the hardware table. But the flow entry still remains in software, so tcp packets to shut down the flow are not sent back to slow path. If syn packet is seen from this new CLOSING state, then this flow enters teardown state, ct state is set to TCP_CONNTRACK_CLOSE state and packet is sent to slow path, so this TCP reopen scenario can be handled by conntrack. TCP_CONNTRACK_CLOSE provides a small timeout that aims at quickly releasing this stale entry from the conntrack table. Moreover, skip hardware re-offload from flowtable software packet if the flow is in CLOSING state. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2025-01-19netfilter: conntrack: rework offload nf_conn timeout extension logicFlorian Westphal-10/+0
Offload nf_conn entries may not see traffic for a very long time. To prevent incorrect 'ct is stale' checks during nf_conntrack table lookup, the gc worker extends the timeout nf_conn entries marked for offload to a large value. The existing logic suffers from a few problems. Garbage collection runs without locks, its unlikely but possible that @ct is removed right after the 'offload' bit test. In that case, the timeout of a new/reallocated nf_conn entry will be increased. Prevent this by obtaining a reference count on the ct object and re-check of the confirmed and offload bits. If those are not set, the ct is being removed, skip the timeout extension in this case. Parallel teardown is also problematic: cpu1 cpu2 gc_worker calls flow_offload_teardown() tests OFFLOAD bit, set clear OFFLOAD bit ct->timeout is repaired (e.g. set to timeout[UDP_CT_REPLIED]) nf_ct_offload_timeout() called expire value is fetched <INTERRUPT> -> NF_CT_DAY timeout for flow that isn't offloaded (and might not see any further packets). Use cmpxchg: if ct->timeout was repaired after the 2nd 'offload bit' test passed, then ct->timeout will only be updated of ct->timeout was not altered in between. As we already have a gc worker for flowtable entries, ct->timeout repair can be handled from the flowtable gc worker. This avoids having flowtable specific logic in the conntrack core and avoids checking entries that were never offloaded. This allows to remove the nf_ct_offload_timeout helper. Its safe to use in the add case, but not on teardown. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2025-01-19netfilter: conntrack: remove skb argument from nf_ct_refreshFlorian Westphal-5/+3
Its not used (and could be NULL), so remove it. This allows to use nf_ct_refresh in places where we don't have an skb without having to double-check that skb == NULL would be safe. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2025-01-19netfilter: nf_tables: Tolerate chains with no remaining hooksPhil Sutter-2/+0
Do not drop a netdev-family chain if the last interface it is registered for vanishes. Users dumping and storing the ruleset upon shutdown to restore it upon next boot may otherwise lose the chain and all contained rules. They will still lose the list of devices, a later patch will fix that. For now, this aligns the event handler's behaviour with that for flowtables. The controversal situation at netns exit should be no problem here: event handler will unregister the hooks, core nftables cleanup code will drop the chain itself. Signed-off-by: Phil Sutter <phil@nwl.cc> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2025-01-19netfilter: nf_tables: Store user-defined hook ifnamePhil Sutter-0/+2
Prepare for hooks with NULL ops.dev pointer (due to non-existent device) and store the interface name and length as specified by the user upon creation. No functional change intended. Signed-off-by: Phil Sutter <phil@nwl.cc> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2025-01-19netfilter: nf_tables: fix set size with rbtree backendPablo Neira Ayuso-0/+6
The existing rbtree implementation uses singleton elements to represent ranges, however, userspace provides a set size according to the number of ranges in the set. Adjust provided userspace set size to the number of singleton elements in the kernel by multiplying the range by two. Check if the no-match all-zero element is already in the set, in such case release one slot in the set size. Fixes: 0ed6389c483d ("netfilter: nf_tables: rename set implementations") Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2025-01-09netfilter: conntrack: add conntrack event timestampFlorian Westphal-0/+12
Nadia Pinaeva writes: I am working on a tool that allows collecting network performance metrics by using conntrack events. Start time of a conntrack entry is used to evaluate seen_reply latency, therefore the sooner it is timestamped, the better the precision is. In particular, when using this tool to compare the performance of the same feature implemented using iptables/nftables/OVS it is crucial to have the entry timestamped earlier to see any difference. At this time, conntrack events can only get timestamped at recv time in userspace, so there can be some delay between the event being generated and the userspace process consuming the message. There is sys/net/netfilter/nf_conntrack_timestamp, which adds a 64bit timestamp (ns resolution) that records start and stop times, but its not suited for this either, start time is the 'hashtable insertion time', not 'conntrack allocation time'. There is concern that moving the start-time moment to conntrack allocation will add overhead in case of flooding, where conntrack entries are allocated and released right away without getting inserted into the hashtable. Also, even if this was changed it would not with events other than new (start time) and destroy (stop time). Pablo suggested to add new CTA_TIMESTAMP_EVENT, this adds this feature. The timestamp is recorded in case both events are requested and the sys/net/netfilter/nf_conntrack_timestamp toggle is enabled. Reported-by: Nadia Pinaeva <n.m.pinaeva@gmail.com> Suggested-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2025-01-03Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski-2/+5
Cross-merge networking fixes after downstream PR (net-6.13-rc6). No conflicts. Adjacent changes: include/linux/if_vlan.h f91a5b808938 ("af_packet: fix vlan_get_protocol_dgram() vs MSG_PEEK") 3f330db30638 ("net: reformat kdoc return statements") Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-12-25netfilter: nft_set_hash: unaligned atomic read on struct nft_set_extPablo Neira Ayuso-2/+5
Access to genmask field in struct nft_set_ext results in unaligned atomic read: [ 72.130109] Unable to handle kernel paging request at virtual address ffff0000c2bb708c [ 72.131036] Mem abort info: [ 72.131213] ESR = 0x0000000096000021 [ 72.131446] EC = 0x25: DABT (current EL), IL = 32 bits [ 72.132209] SET = 0, FnV = 0 [ 72.133216] EA = 0, S1PTW = 0 [ 72.134080] FSC = 0x21: alignment fault [ 72.135593] Data abort info: [ 72.137194] ISV = 0, ISS = 0x00000021, ISS2 = 0x00000000 [ 72.142351] CM = 0, WnR = 0, TnD = 0, TagAccess = 0 [ 72.145989] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 [ 72.150115] swapper pgtable: 4k pages, 48-bit VAs, pgdp=0000000237d27000 [ 72.154893] [ffff0000c2bb708c] pgd=0000000000000000, p4d=180000023ffff403, pud=180000023f84b403, pmd=180000023f835403, +pte=0068000102bb7707 [ 72.163021] Internal error: Oops: 0000000096000021 [#1] SMP [...] [ 72.170041] CPU: 7 UID: 0 PID: 54 Comm: kworker/7:0 Tainted: G E 6.13.0-rc3+ #2 [ 72.170509] Tainted: [E]=UNSIGNED_MODULE [ 72.170720] Hardware name: QEMU QEMU Virtual Machine, BIOS edk2-stable202302-for-qemu 03/01/2023 [ 72.171192] Workqueue: events_power_efficient nft_rhash_gc [nf_tables] [ 72.171552] pstate: 21400005 (nzCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--) [ 72.171915] pc : nft_rhash_gc+0x200/0x2d8 [nf_tables] [ 72.172166] lr : nft_rhash_gc+0x128/0x2d8 [nf_tables] [ 72.172546] sp : ffff800081f2bce0 [ 72.172724] x29: ffff800081f2bd40 x28: ffff0000c2bb708c x27: 0000000000000038 [ 72.173078] x26: ffff0000c6780ef0 x25: ffff0000c643df00 x24: ffff0000c6778f78 [ 72.173431] x23: 000000000000001a x22: ffff0000c4b1f000 x21: ffff0000c6780f78 [ 72.173782] x20: ffff0000c2bb70dc x19: ffff0000c2bb7080 x18: 0000000000000000 [ 72.174135] x17: ffff0000c0a4e1c0 x16: 0000000000003000 x15: 0000ac26d173b978 [ 72.174485] x14: ffffffffffffffff x13: 0000000000000030 x12: ffff0000c6780ef0 [ 72.174841] x11: 0000000000000000 x10: ffff800081f2bcf8 x9 : ffff0000c3000000 [ 72.175193] x8 : 00000000000004be x7 : 0000000000000000 x6 : 0000000000000000 [ 72.175544] x5 : 0000000000000040 x4 : ffff0000c3000010 x3 : 0000000000000000 [ 72.175871] x2 : 0000000000003a98 x1 : ffff0000c2bb708c x0 : 0000000000000004 [ 72.176207] Call trace: [ 72.176316] nft_rhash_gc+0x200/0x2d8 [nf_tables] (P) [ 72.176653] process_one_work+0x178/0x3d0 [ 72.176831] worker_thread+0x200/0x3f0 [ 72.176995] kthread+0xe8/0xf8 [ 72.177130] ret_from_fork+0x10/0x20 [ 72.177289] Code: 54fff984 d503201f d2800080 91003261 (f820303f) [ 72.177557] ---[ end trace 0000000000000000 ]--- Align struct nft_set_ext to word size to address this and documentation it. pahole reports that this increases the size of elements for rhash and pipapo in 8 bytes on x86_64. Fixes: 7ffc7481153b ("netfilter: nft_set_hash: skip duplicated elements pending gc run") Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>