usb: gadget: u_serial: Fix the issue that gs_start_io crashed due to accessing null pointer

{
  "id": "f39c3cae2726f0f4ae266b903eaa2336d477ad1073601d5b82db2882ce2ff2d9",
  "url": "https://osv.dev/vulnerability/CVE-2024-56670",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "usb: gadget: u_serial: Fix the issue that gs_start_io crashed due to accessing null pointer",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: usb: gadget: u_serial: Fix the issue that gs_start_io crashed due to accessing null pointer Considering that in some extreme cases, when u_serial driver is accessed by multiple threads, Thread A is executing the open operation and calling the gs_open, Thread B is executing the disconnect operation and calling the gserial_disconnect function,The port->port_usb pointer will be set to NULL. E.g. Thread A Thread B gs_open() gadget_unbind_driver() gs_start_io() composite_disconnect() gs_start_rx() gserial_disconnect() ... ... spin_unlock(&port->port_lock) status = usb_ep_queue() spin_lock(&port->port_lock) spin_lock(&port->port_lock) port->port_usb = NULL gs_free_requests(port->port_usb->in) spin_unlock(&port->port_lock) Crash This causes thread A to access a null pointer (port->port_usb is null) when calling the gs_free_requests function, causing a crash. If port_usb is NULL, the release request will be skipped as it will be done by gserial_disconnect. So add a null pointer check to gs_start_io before attempting to access the value of the pointer port->port_usb. Call trace: gs_start_io+0x164/0x25c gs_open+0x108/0x13c tty_open+0x314/0x638 chrdev_open+0x1b8/0x258 do_dentry_open+0x2c4/0x700 vfs_open+0x2c/0x3c path_openat+0xa64/0xc60 do_filp_open+0xb8/0x164 do_sys_openat2+0x84/0xf0 __arm64_sys_openat+0x70/0x9c invoke_syscall+0x58/0x114 el0_svc_common+0x80/0xe0 do_el0_svc+0x1c/0x28 el0_svc+0x38/0x68",
    "evidence": "osv:CVE-2024-56670",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.4.288",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.10.232",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.15.175",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.121",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.67",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.6",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "CVE-2024-56670",
      "aliases": [
        "CVE-2024-56670"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
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                  "introduced": "c1dca562be8ada614ef193aa246c6f8705bcd6b9"
                },
                {
                  "fixed": "4efdfdc32d8d6307f968cd99f1db64468471bab1"
                },
                {
                  "fixed": "28b3c03a6790de1f6f2683919ad657840f0f0f58"
                },
                {
                  "fixed": "1247e1df086aa6c17ab53cd1bedce70dd7132765"
                },
                {
                  "fixed": "c83213b6649d22656b3a4e92544ceeea8a2c6c07"
                },
                {
                  "fixed": "8ca07a3d18f39b1669927ef536e485787e856df6"
                },
                {
                  "fixed": "dd6b0ca6025f64ccb465a6a3460c5b0307ed9c44"
                },
                {
                  "fixed": "4cfbca86f6a8b801f3254e0e3c8f2b1d2d64be2b"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-56670.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "2.6.27"
                },
                {
                  "fixed": "5.4.288"
                }
              ]
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            {
              "type": "ECOSYSTEM",
              "events": [
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                  "introduced": "5.5.0"
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                  "fixed": "5.15.175"
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            {
              "type": "ECOSYSTEM",
              "events": [
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                  "introduced": "5.16.0"
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                {
                  "fixed": "6.1.121"
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              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.2.0"
                },
                {
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                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.7.0"
                },
                {
                  "fixed": "6.12.6"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-56670.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:26.575632549Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/1247e1df086aa6c17ab53cd1bedce70dd7132765",
        "https://git.kernel.org/stable/c/28b3c03a6790de1f6f2683919ad657840f0f0f58",
        "https://git.kernel.org/stable/c/4cfbca86f6a8b801f3254e0e3c8f2b1d2d64be2b",
        "https://git.kernel.org/stable/c/4efdfdc32d8d6307f968cd99f1db64468471bab1",
        "https://git.kernel.org/stable/c/8ca07a3d18f39b1669927ef536e485787e856df6",
        "https://git.kernel.org/stable/c/c83213b6649d22656b3a4e92544ceeea8a2c6c07",
        "https://git.kernel.org/stable/c/dd6b0ca6025f64ccb465a6a3460c5b0307ed9c44",
        "https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html",
        "https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/56xxx/CVE-2024-56670.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2024-56670",
        "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/2024/56xxx/CVE-2024-56670.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2024-56670",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 493201,
  "published_at": "2024-12-27T15:06:31.611+00:00"
}