ghsa-677c-pqcw-qh84
Vulnerability from github
Published
2024-06-19 15:30
Modified
2024-11-01 15:31
Severity ?
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Details

In the Linux kernel, the following vulnerability has been resolved:

mptcp: clear 'kern' flag from fallback sockets

The mptcp ULP extension relies on sk->sk_sock_kern being set correctly: It prevents setsockopt(fd, IPPROTO_TCP, TCP_ULP, "mptcp", 6); from working for plain tcp sockets (any userspace-exposed socket).

But in case of fallback, accept() can return a plain tcp sk. In such case, sk is still tagged as 'kernel' and setsockopt will work.

This will crash the kernel, The subflow extension has a NULL ctx->conn mptcp socket:

BUG: KASAN: null-ptr-deref in subflow_data_ready+0x181/0x2b0 Call Trace: tcp_data_ready+0xf8/0x370 [..]

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{
  "affected": [],
  "aliases": [
    "CVE-2021-47593"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-476"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-06-19T15:15:53Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: clear \u0027kern\u0027 flag from fallback sockets\n\nThe mptcp ULP extension relies on sk-\u003esk_sock_kern being set correctly:\nIt prevents setsockopt(fd, IPPROTO_TCP, TCP_ULP, \"mptcp\", 6); from\nworking for plain tcp sockets (any userspace-exposed socket).\n\nBut in case of fallback, accept() can return a plain tcp sk.\nIn such case, sk is still tagged as \u0027kernel\u0027 and setsockopt will work.\n\nThis will crash the kernel, The subflow extension has a NULL ctx-\u003econn\nmptcp socket:\n\nBUG: KASAN: null-ptr-deref in subflow_data_ready+0x181/0x2b0\nCall Trace:\n tcp_data_ready+0xf8/0x370\n [..]",
  "id": "GHSA-677c-pqcw-qh84",
  "modified": "2024-11-01T15:31:45Z",
  "published": "2024-06-19T15:30:55Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-47593"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/451f1eded7f56e93aaf52eb547ba97742d9c0e97"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c26ac0ea3a91c210cf90452e625dc441adf3e549"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d6692b3b97bdc165d150f4c1505751a323a80717"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}


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