CVE-2021-47214
Vulnerability from cvelistv5
Published
2024-04-10 19:01
Modified
2024-11-04 12:01
Severity ?
Summary
hugetlb, userfaultfd: fix reservation restore on userfaultfd error
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b5069d44e2fbc4a9093d005b3ef0949add3dd27e
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/cc30042df6fcc82ea18acf0dace831503e60a0b7
af854a3a-2127-422b-91ae-364da2661108https://git.kernel.org/stable/c/b5069d44e2fbc4a9093d005b3ef0949add3dd27e
af854a3a-2127-422b-91ae-364da2661108https://git.kernel.org/stable/c/cc30042df6fcc82ea18acf0dace831503e60a0b7
Impacted products
Vendor Product Version
Linux Linux Version: 5.14
Show details on NVD website

To clipboard 

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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nhugetlb, userfaultfd: fix reservation restore on userfaultfd error\n\nCurrently in the is_continue case in hugetlb_mcopy_atomic_pte(), if we\nbail out using \"goto out_release_unlock;\" in the cases where idx \u003e=\nsize, or !huge_pte_none(), the code will detect that new_pagecache_page\n== false, and so call restore_reserve_on_error().  In this case I see\nrestore_reserve_on_error() delete the reservation, and the following\ncall to remove_inode_hugepages() will increment h-\u003eresv_hugepages\ncausing a 100% reproducible leak.\n\nWe should treat the is_continue case similar to adding a page into the\npagecache and set new_pagecache_page to true, to indicate that there is\nno reservation to restore on the error path, and we need not call\nrestore_reserve_on_error().  Rename new_pagecache_page to\npage_in_pagecache to make that clear."
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    "nvd": "{\"cve\":{\"id\":\"CVE-2021-47214\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2024-04-10T19:15:48.680\",\"lastModified\":\"2024-11-21T06:35:38.583\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nhugetlb, userfaultfd: fix reservation restore on userfaultfd error\\n\\nCurrently in the is_continue case in hugetlb_mcopy_atomic_pte(), if we\\nbail out using \\\"goto out_release_unlock;\\\" in the cases where idx \u003e=\\nsize, or !huge_pte_none(), the code will detect that new_pagecache_page\\n== false, and so call restore_reserve_on_error().  In this case I see\\nrestore_reserve_on_error() delete the reservation, and the following\\ncall to remove_inode_hugepages() will increment h-\u003eresv_hugepages\\ncausing a 100% reproducible leak.\\n\\nWe should treat the is_continue case similar to adding a page into the\\npagecache and set new_pagecache_page to true, to indicate that there is\\nno reservation to restore on the error path, and we need not call\\nrestore_reserve_on_error().  Rename new_pagecache_page to\\npage_in_pagecache to make that clear.\"},{\"lang\":\"es\",\"value\":\"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: hugetlb, userfaultfd: se corrige el error de restauraci\u00f3n de reserva en userfaultfd Actualmente, en el caso is_continue en hugetlb_mcopy_atomic_pte(), si salimos usando \\\"goto out_release_unlock;\\\" en los casos donde idx \u0026gt;= size, o !huge_pte_none(), el c\u00f3digo detectar\u00e1 que new_pagecache_page == false, y por lo tanto llamar\u00e1 a restore_reserve_on_error(). En este caso, veo que restore_reserve_on_error() elimina la reserva, y la siguiente llamada a remove_inode_hugepages() incrementar\u00e1 h-\u0026gt;resv_hugepages causando una fuga 100% reproducible. Deber\u00edamos tratar el caso is_continue de forma similar a agregar una p\u00e1gina al pagecache y establecer new_pagecache_page en true, para indicar que no hay ninguna reserva para restaurar en la ruta del error, y no necesitamos llamar a restore_reserve_on_error(). Cambie el nombre new_pagecache_page a page_in_pagecache para que quede claro.\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/b5069d44e2fbc4a9093d005b3ef0949add3dd27e\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/cc30042df6fcc82ea18acf0dace831503e60a0b7\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/b5069d44e2fbc4a9093d005b3ef0949add3dd27e\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\"},{\"url\":\"https://git.kernel.org/stable/c/cc30042df6fcc82ea18acf0dace831503e60a0b7\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\"}]}}"
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