ghsa-2wc3-h48p-9gpq
Vulnerability from github
Published
2024-05-01 06:31
Modified
2024-05-03 03:30
Details

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

usb: gadget: f_ncm: Fix UAF ncm object at re-bind after usb ep transport error

When ncm function is working and then stop usb0 interface for link down, eth_stop() is called. At this piont, accidentally if usb transport error should happen in usb_ep_enable(), 'in_ep' and/or 'out_ep' may not be enabled.

After that, ncm_disable() is called to disable for ncm unbind but gether_disconnect() is never called since 'in_ep' is not enabled.

As the result, ncm object is released in ncm unbind but 'dev->port_usb' associated to 'ncm->port' is not NULL.

And when ncm bind again to recover netdev, ncm object is reallocated but usb0 interface is already associated to previous released ncm object.

Therefore, once usb0 interface is up and eth_start_xmit() is called, released ncm object is dereferrenced and it might cause use-after-free memory.

[function unlink via configfs] usb0: eth_stop dev->port_usb=ffffff9b179c3200 --> error happens in usb_ep_enable(). NCM: ncm_disable: ncm=ffffff9b179c3200 --> no gether_disconnect() since ncm->port.in_ep->enabled is false. NCM: ncm_unbind: ncm unbind ncm=ffffff9b179c3200 NCM: ncm_free: ncm free ncm=ffffff9b179c3200 <-- released ncm

[function link via configfs] NCM: ncm_alloc: ncm alloc ncm=ffffff9ac4f8a000 NCM: ncm_bind: ncm bind ncm=ffffff9ac4f8a000 NCM: ncm_set_alt: ncm=ffffff9ac4f8a000 alt=0 usb0: eth_open dev->port_usb=ffffff9b179c3200 <-- previous released ncm usb0: eth_start dev->port_usb=ffffff9b179c3200 <-- eth_start_xmit() --> dev->wrap() Unable to handle kernel paging request at virtual address dead00000000014f

This patch addresses the issue by checking if 'ncm->netdev' is not NULL at ncm_disable() to call gether_disconnect() to deassociate 'dev->port_usb'. It's more reasonable to check 'ncm->netdev' to call gether_connect/disconnect rather than check 'ncm->port.in_ep->enabled' since it might not be enabled but the gether connection might be established.

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{
  "affected": [],
  "aliases": [
    "CVE-2024-26996"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-05-01T06:15:17Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: f_ncm: Fix UAF ncm object at re-bind after usb ep transport error\n\nWhen ncm function is working and then stop usb0 interface for link down,\neth_stop() is called. At this piont, accidentally if usb transport error\nshould happen in usb_ep_enable(), \u0027in_ep\u0027 and/or \u0027out_ep\u0027 may not be enabled.\n\nAfter that, ncm_disable() is called to disable for ncm unbind\nbut gether_disconnect() is never called since \u0027in_ep\u0027 is not enabled.\n\nAs the result, ncm object is released in ncm unbind\nbut \u0027dev-\u003eport_usb\u0027 associated to \u0027ncm-\u003eport\u0027 is not NULL.\n\nAnd when ncm bind again to recover netdev, ncm object is reallocated\nbut usb0 interface is already associated to previous released ncm object.\n\nTherefore, once usb0 interface is up and eth_start_xmit() is called,\nreleased ncm object is dereferrenced and it might cause use-after-free memory.\n\n[function unlink via configfs]\n  usb0: eth_stop dev-\u003eport_usb=ffffff9b179c3200\n  --\u003e error happens in usb_ep_enable().\n  NCM: ncm_disable: ncm=ffffff9b179c3200\n  --\u003e no gether_disconnect() since ncm-\u003eport.in_ep-\u003eenabled is false.\n  NCM: ncm_unbind: ncm unbind ncm=ffffff9b179c3200\n  NCM: ncm_free: ncm free ncm=ffffff9b179c3200   \u003c-- released ncm\n\n[function link via configfs]\n  NCM: ncm_alloc: ncm alloc ncm=ffffff9ac4f8a000\n  NCM: ncm_bind: ncm bind ncm=ffffff9ac4f8a000\n  NCM: ncm_set_alt: ncm=ffffff9ac4f8a000 alt=0\n  usb0: eth_open dev-\u003eport_usb=ffffff9b179c3200  \u003c-- previous released ncm\n  usb0: eth_start dev-\u003eport_usb=ffffff9b179c3200 \u003c--\n  eth_start_xmit()\n  --\u003e dev-\u003ewrap()\n  Unable to handle kernel paging request at virtual address dead00000000014f\n\nThis patch addresses the issue by checking if \u0027ncm-\u003enetdev\u0027 is not NULL at\nncm_disable() to call gether_disconnect() to deassociate \u0027dev-\u003eport_usb\u0027.\nIt\u0027s more reasonable to check \u0027ncm-\u003enetdev\u0027 to call gether_connect/disconnect\nrather than check \u0027ncm-\u003eport.in_ep-\u003eenabled\u0027 since it might not be enabled\nbut the gether connection might be established.",
  "id": "GHSA-2wc3-h48p-9gpq",
  "modified": "2024-05-03T03:30:46Z",
  "published": "2024-05-01T06:31:43Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-26996"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0588bbbd718a8130b98c54518f1e0b569ce60a93"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6334b8e4553cc69f51e383c9de545082213d785e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7250326cbb1f4f90391ac511a126b936cefb5bb7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7f67c2020cb08499c400abf0fc32c65e4d9a09ca"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f356fd0cbd9c9cbd0854657a80d1608d0d732db3"
    },
    {
      "type": "WEB",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/4EZ6PJW7VOZ224TD7N4JZNU6KV32ZJ53"
    },
    {
      "type": "WEB",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/DAMSOZXJEPUOXW33WZYWCVAY7Z5S7OOY"
    },
    {
      "type": "WEB",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/GCBZZEC7L7KTWWAS2NLJK6SO3IZIL4WW"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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