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{
    "id": 2228490,
    "url": "http://patchwork.ozlabs.org/api/1.1/covers/2228490/?format=api",
    "web_url": "http://patchwork.ozlabs.org/project/netfilter-devel/cover/cover.1777214801.git.lucien.xin@gmail.com/",
    "project": {
        "id": 26,
        "url": "http://patchwork.ozlabs.org/api/1.1/projects/26/?format=api",
        "name": "Netfilter Development",
        "link_name": "netfilter-devel",
        "list_id": "netfilter-devel.vger.kernel.org",
        "list_email": "netfilter-devel@vger.kernel.org",
        "web_url": null,
        "scm_url": null,
        "webscm_url": null
    },
    "msgid": "<cover.1777214801.git.lucien.xin@gmail.com>",
    "date": "2026-04-26T14:46:39",
    "name": "[net,v2,0/2] sctp: fix a vtag verification failure caused by stale INITs",
    "submitter": {
        "id": 61073,
        "url": "http://patchwork.ozlabs.org/api/1.1/people/61073/?format=api",
        "name": "Xin Long",
        "email": "lucien.xin@gmail.com"
    },
    "mbox": "http://patchwork.ozlabs.org/project/netfilter-devel/cover/cover.1777214801.git.lucien.xin@gmail.com/mbox/",
    "series": [
        {
            "id": 501540,
            "url": "http://patchwork.ozlabs.org/api/1.1/series/501540/?format=api",
            "web_url": "http://patchwork.ozlabs.org/project/netfilter-devel/list/?series=501540",
            "date": "2026-04-26T14:46:39",
            "name": "sctp: fix a vtag verification failure caused by stale INITs",
            "version": 2,
            "mbox": "http://patchwork.ozlabs.org/series/501540/mbox/"
        }
    ],
    "comments": "http://patchwork.ozlabs.org/api/covers/2228490/comments/",
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        "From": "Xin Long <lucien.xin@gmail.com>",
        "To": "network dev <netdev@vger.kernel.org>,\n\tnetfilter-devel@vger.kernel.org,\n\tlinux-sctp@vger.kernel.org",
        "Cc": "davem@davemloft.net,\n\tkuba@kernel.org,\n\tEric Dumazet <edumazet@google.com>,\n\tPaolo Abeni <pabeni@redhat.com>,\n\tSimon Horman <horms@kernel.org>,\n\tPablo Neira Ayuso <pablo@netfilter.org>,\n\tFlorian Westphal <fw@strlen.de>,\n\tPhil Sutter <phil@nwl.cc>,\n\tMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>,\n\tYi Chen <yiche.cy@gmail.com>",
        "Subject": "[PATCH net v2 0/2] sctp: fix a vtag verification failure caused by\n stale INITs",
        "Date": "Sun, 26 Apr 2026 10:46:39 -0400",
        "Message-ID": "<cover.1777214801.git.lucien.xin@gmail.com>",
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    },
    "content": "Similar to Scenario B in commit 8e56b063c865 ( netfilter: handle the\nconnecting collision properly in nf_conntrack_proto_sctp\"):\n\nScenario B: INIT_ACK is delayed until the peer completes its own handshake\n\n  192.168.1.2 > 192.168.1.1: sctp (1) [INIT] [init tag: 3922216408]\n    192.168.1.1 > 192.168.1.2: sctp (1) [INIT] [init tag: 144230885]\n    192.168.1.2 > 192.168.1.1: sctp (1) [INIT ACK] [init tag: 3922216408]\n    192.168.1.1 > 192.168.1.2: sctp (1) [COOKIE ECHO]\n    192.168.1.2 > 192.168.1.1: sctp (1) [COOKIE ACK]\n  192.168.1.1 > 192.168.1.2: sctp (1) [INIT ACK] [init tag: 3914796021] *\n\nThere is another case:\n\nScenario F: INIT is delayed until the peer completes its own handshake\n\n  192.168.1.2 > 192.168.1.1: sctp (1) [INIT] [init tag: 3922216408]\n  (OVS upcall)\n    192.168.1.1 > 192.168.1.2: sctp (1) [INIT] [init tag: 144230885]\n    192.168.1.2 > 192.168.1.1: sctp (1) [INIT ACK] [init tag: 3922216408]\n    192.168.1.1 > 192.168.1.2: sctp (1) [COOKIE ECHO]\n    192.168.1.2 > 192.168.1.1: sctp (1) [COOKIE ACK]\n  192.168.1.2 > 192.168.1.1: sctp (1) [INIT] [init tag: 3922216408]\n  (delayed)\n  192.168.1.1 > 192.168.1.2: sctp (1) [INIT ACK] [init tag: 3914796021] *\n\nIn this case, the delayed INIT (e.g. due to OVS upcall) is recorded by\nconntrack, which prevents vtag verification from dropping the unexpected\nINIT-ACK in nf_conntrack_sctp_packet():\n\n  vtag = ct->proto.sctp.vtag[!dir];\n  if (!ct->proto.sctp.init[!dir] && vtag && vtag != ih->init_tag)\n          goto out_unlock;\n\nThis happens because ct->proto.sctp.init[!dir] is set by the delayed INIT,\neven though it is stale.\n\nFix this in two parts:\n\n- In netfilter: Do not record INITs whose init_tag matches the peer vtag,\n  as they carry no new handshake state in the 1st patch.\n\n- In SCTP: Prevent endpoints from responding to such INITs with INIT-ACK,\n  ensuring correctness even when middleboxes lack the netfilter fix in\n  the 2nd patch.\n\nA follow-up selftest for this scenario will be posted in a separate patch\nby Yi Chen.\n\nXin Long (2):\n  netfilter: skip recording stale or retransmitted INIT\n  sctp: discard stale INIT after handshake completion\n\n net/netfilter/nf_conntrack_proto_sctp.c | 10 +++++++---\n net/sctp/sm_statefuns.c                 |  6 ++++++\n 2 files changed, 13 insertions(+), 3 deletions(-)"
}