VMCI: Fix memcpy() run-time warning in dg_dispatch_as_host()

{
  "id": "bbc309e14285fc506359b0f8a895be293051fbebbb9e5547649c73bcb0a4edfd",
  "url": "https://osv.dev/vulnerability/CVE-2024-35944",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "VMCI: Fix memcpy() run-time warning in dg_dispatch_as_host()",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: VMCI: Fix memcpy() run-time warning in dg_dispatch_as_host() Syzkaller hit 'WARNING in dg_dispatch_as_host' bug. memcpy: detected field-spanning write (size 56) of single field \"&dg_info->msg\" at drivers/misc/vmw_vmci/vmci_datagram.c:237 (size 24) WARNING: CPU: 0 PID: 1555 at drivers/misc/vmw_vmci/vmci_datagram.c:237 dg_dispatch_as_host+0x88e/0xa60 drivers/misc/vmw_vmci/vmci_datagram.c:237 Some code commentry, based on my understanding: 544 #define VMCI_DG_SIZE(_dg) (VMCI_DG_HEADERSIZE + (size_t)(_dg)->payload_size) /// This is 24 + payload_size memcpy(&dg_info->msg, dg, dg_size); Destination = dg_info->msg ---> this is a 24 byte structure(struct vmci_datagram) Source = dg --> this is a 24 byte structure (struct vmci_datagram) Size = dg_size = 24 + payload_size {payload_size = 56-24 =32} -- Syzkaller managed to set payload_size to 32. 35 struct delayed_datagram_info { 36 struct datagram_entry *entry; 37 struct work_struct work; 38 bool in_dg_host_queue; 39 /* msg and msg_payload must be together. */ 40 struct vmci_datagram msg; 41 u8 msg_payload[]; 42 }; So those extra bytes of payload are copied into msg_payload[], a run time warning is seen while fuzzing with Syzkaller. One possible way to fix the warning is to split the memcpy() into two parts -- one -- direct assignment of msg and second taking care of payload. Gustavo quoted: \"Under FORTIFY_SOURCE we should not copy data across multiple members in a stru",
    "evidence": "osv:CVE-2024-35944",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "4.19.312",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.4.274",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.10.215",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.15.155",
            "evidence": "/affected/1/ranges"
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          {
            "value": "6.1.86",
            "evidence": "/affected/1/ranges"
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          {
            "value": "6.6.27",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.8.6",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2024-35944",
      "aliases": [
        "CVE-2024-35944"
      ],
      "affected": [
        {
          "ranges": [
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              "type": "GIT",
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                {
                  "fixed": "f15eca95138b3d4ec17b63c3c1937b0aa0d3624b"
                },
                {
                  "fixed": "ad78c5047dc4076d0b3c4fad4f42ffe9c86e8100"
                },
                {
                  "fixed": "130b0cd064874e0d0f58e18fb00e6f3993e90c74"
                },
                {
                  "fixed": "feacd430b42bbfa9ab3ed9e4f38b86c43e348c75"
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                {
                  "fixed": "dae70a57565686f16089737adb8ac64471570f73"
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                {
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          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-35944.json"
          }
        },
        {
          "ranges": [
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              "type": "ECOSYSTEM",
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                  "introduced": "3.9.0"
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          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-35944.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:46.692605031Z",
      "provider": "osv",
      "references": [
        "https://cert-portal.siemens.com/productcert/html/ssa-265688.html",
        "https://cert-portal.siemens.com/productcert/html/ssa-398330.html",
        "https://git.kernel.org/stable/c/130b0cd064874e0d0f58e18fb00e6f3993e90c74",
        "https://git.kernel.org/stable/c/19b070fefd0d024af3daa7329cbc0d00de5302ec",
        "https://git.kernel.org/stable/c/491a1eb07c2bd8841d63cb5263455e185be5866f",
        "https://git.kernel.org/stable/c/ad78c5047dc4076d0b3c4fad4f42ffe9c86e8100",
        "https://git.kernel.org/stable/c/dae70a57565686f16089737adb8ac64471570f73",
        "https://git.kernel.org/stable/c/e87bb99d2df6512d8ee37a5d63d2ca9a39a8c051",
        "https://git.kernel.org/stable/c/f15eca95138b3d4ec17b63c3c1937b0aa0d3624b",
        "https://git.kernel.org/stable/c/feacd430b42bbfa9ab3ed9e4f38b86c43e348c75",
        "https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html",
        "https://lists.debian.org/debian-lts-announce/2024/06/msg00020.html",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/35xxx/CVE-2024-35944.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2024-35944",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/35xxx/CVE-2024-35944.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2024-35944",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 514487,
  "published_at": "2024-05-19T10:10:48.183+00:00"
}