ghsa-275j-88f3-q9g5
Vulnerability from github
Published
2025-07-03 09:30
Modified
2025-07-17 18:31
Details

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

VMCI: fix race between vmci_host_setup_notify and vmci_ctx_unset_notify

During our test, it is found that a warning can be trigger in try_grab_folio as follow:

------------[ cut here ]------------ WARNING: CPU: 0 PID: 1678 at mm/gup.c:147 try_grab_folio+0x106/0x130 Modules linked in: CPU: 0 UID: 0 PID: 1678 Comm: syz.3.31 Not tainted 6.15.0-rc5 #163 PREEMPT(undef) RIP: 0010:try_grab_folio+0x106/0x130 Call Trace: follow_huge_pmd+0x240/0x8e0 follow_pmd_mask.constprop.0.isra.0+0x40b/0x5c0 follow_pud_mask.constprop.0.isra.0+0x14a/0x170 follow_page_mask+0x1c2/0x1f0 __get_user_pages+0x176/0x950 __gup_longterm_locked+0x15b/0x1060 ? gup_fast+0x120/0x1f0 gup_fast_fallback+0x17e/0x230 get_user_pages_fast+0x5f/0x80 vmci_host_unlocked_ioctl+0x21c/0xf80 RIP: 0033:0x54d2cd ---[ end trace 0000000000000000 ]---

Digging into the source, context->notify_page may init by get_user_pages_fast and can be seen in vmci_ctx_unset_notify which will try to put_page. However get_user_pages_fast is not finished here and lead to following try_grab_folio warning. The race condition is shown as follow:

cpu0 cpu1 vmci_host_do_set_notify vmci_host_setup_notify get_user_pages_fast(uva, 1, FOLL_WRITE, &context->notify_page); lockless_pages_from_mm gup_pgd_range gup_huge_pmd // update &context->notify_page vmci_host_do_set_notify vmci_ctx_unset_notify notify_page = context->notify_page; if (notify_page) put_page(notify_page); // page is freed __gup_longterm_locked __get_user_pages follow_trans_huge_pmd try_grab_folio // warn here

To slove this, use local variable page to make notify_page can be seen after finish get_user_pages_fast.

Show details on source website


{
  "affected": [],
  "aliases": [
    "CVE-2025-38102"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-07-03T09:15:23Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nVMCI: fix race between vmci_host_setup_notify and vmci_ctx_unset_notify\n\nDuring our test, it is found that a warning can be trigger in try_grab_folio\nas follow:\n\n  ------------[ cut here ]------------\n  WARNING: CPU: 0 PID: 1678 at mm/gup.c:147 try_grab_folio+0x106/0x130\n  Modules linked in:\n  CPU: 0 UID: 0 PID: 1678 Comm: syz.3.31 Not tainted 6.15.0-rc5 #163 PREEMPT(undef)\n  RIP: 0010:try_grab_folio+0x106/0x130\n  Call Trace:\n   \u003cTASK\u003e\n   follow_huge_pmd+0x240/0x8e0\n   follow_pmd_mask.constprop.0.isra.0+0x40b/0x5c0\n   follow_pud_mask.constprop.0.isra.0+0x14a/0x170\n   follow_page_mask+0x1c2/0x1f0\n   __get_user_pages+0x176/0x950\n   __gup_longterm_locked+0x15b/0x1060\n   ? gup_fast+0x120/0x1f0\n   gup_fast_fallback+0x17e/0x230\n   get_user_pages_fast+0x5f/0x80\n   vmci_host_unlocked_ioctl+0x21c/0xf80\n  RIP: 0033:0x54d2cd\n  ---[ end trace 0000000000000000 ]---\n\nDigging into the source, context-\u003enotify_page may init by get_user_pages_fast\nand can be seen in vmci_ctx_unset_notify which will try to put_page. However\nget_user_pages_fast is not finished here and lead to following\ntry_grab_folio warning. The race condition is shown as follow:\n\ncpu0\t\t\tcpu1\nvmci_host_do_set_notify\nvmci_host_setup_notify\nget_user_pages_fast(uva, 1, FOLL_WRITE, \u0026context-\u003enotify_page);\nlockless_pages_from_mm\ngup_pgd_range\ngup_huge_pmd  // update \u0026context-\u003enotify_page\n\t\t\tvmci_host_do_set_notify\n\t\t\tvmci_ctx_unset_notify\n\t\t\tnotify_page = context-\u003enotify_page;\n\t\t\tif (notify_page)\n\t\t\tput_page(notify_page);\t// page is freed\n__gup_longterm_locked\n__get_user_pages\nfollow_trans_huge_pmd\ntry_grab_folio // warn here\n\nTo slove this, use local variable page to make notify_page can be seen\nafter finish get_user_pages_fast.",
  "id": "GHSA-275j-88f3-q9g5",
  "modified": "2025-07-17T18:31:09Z",
  "published": "2025-07-03T09:30:33Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-38102"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/00ddc7dad55b7bbb78df80d6e174d0c4764dea0c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1bd6406fb5f36c2bb1e96e27d4c3e9f4d09edde4"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/468aec888f838ce5174b96e0cb4396790d6f60ca"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/58a90db70aa6616411e5f69d1982d9b1dd97d774"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6e3af836805ed1d7a699f76ec798626198917aa4"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/74095bbbb19ca74a0368d857603a2438c88ca86c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/75b5313c80c39a26d27cbb602f968a05576c36f9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b4209e4b778e4e57d0636e1c9fc07a924dbc6043"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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