ghsa-cmcr-4938-mjgj
Vulnerability from github
Published
2024-05-22 09:31
Modified
2024-05-22 09:31
Details

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

KVM: arm64: Fix host stage-2 PGD refcount

The KVM page-table library refcounts the pages of concatenated stage-2 PGDs individually. However, when running KVM in protected mode, the host's stage-2 PGD is currently managed by EL2 as a single high-order compound page, which can cause the refcount of the tail pages to reach 0 when they shouldn't, hence corrupting the page-table.

Fix this by introducing a new hyp_split_page() helper in the EL2 page allocator (matching the kernel's split_page() function), and make use of it from host_s2_zalloc_pages_exact().

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{
   affected: [],
   aliases: [
      "CVE-2021-47450",
   ],
   database_specific: {
      cwe_ids: [],
      github_reviewed: false,
      github_reviewed_at: null,
      nvd_published_at: "2024-05-22T07:15:10Z",
      severity: null,
   },
   details: "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: arm64: Fix host stage-2 PGD refcount\n\nThe KVM page-table library refcounts the pages of concatenated stage-2\nPGDs individually. However, when running KVM in protected mode, the\nhost's stage-2 PGD is currently managed by EL2 as a single high-order\ncompound page, which can cause the refcount of the tail pages to reach 0\nwhen they shouldn't, hence corrupting the page-table.\n\nFix this by introducing a new hyp_split_page() helper in the EL2 page\nallocator (matching the kernel's split_page() function), and make use of\nit from host_s2_zalloc_pages_exact().",
   id: "GHSA-cmcr-4938-mjgj",
   modified: "2024-05-22T09:31:45Z",
   published: "2024-05-22T09:31:45Z",
   references: [
      {
         type: "ADVISORY",
         url: "https://nvd.nist.gov/vuln/detail/CVE-2021-47450",
      },
      {
         type: "WEB",
         url: "https://git.kernel.org/stable/c/1d58a17ef54599506d44c45ac95be27273a4d2b1",
      },
      {
         type: "WEB",
         url: "https://git.kernel.org/stable/c/b372264c66ef78f2cab44e877fbd765ad6d24c39",
      },
   ],
   schema_version: "1.4.0",
   severity: [],
}


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