cve-2021-47450
Vulnerability from cvelistv5
Published
2024-05-22 06:19
Modified
2024-11-04 12:06
Severity ?
Summary
KVM: arm64: Fix host stage-2 PGD refcount
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1d58a17ef54599506d44c45ac95be27273a4d2b1
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b372264c66ef78f2cab44e877fbd765ad6d24c39
Impacted products
LinuxLinux
LinuxLinux
Show details on NVD website

To clipboard 

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          "value": "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\u0027s 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\u0027t, hence corrupting the page-table.\n\nFix this by introducing a new hyp_split_page() helper in the EL2 page\nallocator (matching the kernel\u0027s split_page() function), and make use of\nit from host_s2_zalloc_pages_exact()."
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    "nvd": "{\"cve\":{\"id\":\"CVE-2021-47450\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2024-05-22T07:15:10.143\",\"lastModified\":\"2024-05-22T12:46:53.887\",\"vulnStatus\":\"Awaiting Analysis\",\"descriptions\":[{\"lang\":\"en\",\"value\":\"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\u0027s 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\u0027t, hence corrupting the page-table.\\n\\nFix this by introducing a new hyp_split_page() helper in the EL2 page\\nallocator (matching the kernel\u0027s split_page() function), and make use of\\nit from host_s2_zalloc_pages_exact().\"},{\"lang\":\"es\",\"value\":\"En el kernel de Linux, se resolvi\u00f3 la siguiente vulnerabilidad: KVM: arm64: corrige el recuento de PGD de etapa 2 del host La librer\u00eda de tablas de p\u00e1ginas de KVM vuelve a contar las p\u00e1ginas de los PGD de etapa 2 concatenados individualmente. Sin embargo, cuando se ejecuta KVM en modo protegido, EL2 administra actualmente el PGD de etapa 2 del host como una \u00fanica p\u00e1gina compuesta de alto orden, lo que puede causar que el recuento de las p\u00e1ginas finales llegue a 0 cuando no deber\u00eda, corrompiendo as\u00ed el tabla de p\u00e1ginas. Solucione este problema introduciendo un nuevo asistente hyp_split_page() en el asignador de p\u00e1ginas EL2 (que coincida con la funci\u00f3n split_page() del kernel) y util\u00edcelo desde host_s2_zalloc_pages_exact().\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/1d58a17ef54599506d44c45ac95be27273a4d2b1\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/b372264c66ef78f2cab44e877fbd765ad6d24c39\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
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