CVE-2021-47256

{"id": "CVE-2021-47256", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 5.5, "attackVector": "LOCAL", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 1.8}]}, "published": "2024-05-21T15:15:14.380", "references": [{"url": "https://git.kernel.org/stable/c/28788dc5c70597395b6b451dae4549bbaa8e2c56", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/566345aaabac853aa866f53a219c4b02a6beb527", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/6d210d547adc2218ef8b5bcf23518c5f2f1fd872", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/9e379da727a7a031be9b877cde7b9c34a0fb8306", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/d05267fd27a5c4f54e06daefa3035995d765ca0c", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/e8675d291ac007e1c636870db880f837a9ea112a", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/28788dc5c70597395b6b451dae4549bbaa8e2c56", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/566345aaabac853aa866f53a219c4b02a6beb527", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/6d210d547adc2218ef8b5bcf23518c5f2f1fd872", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/9e379da727a7a031be9b877cde7b9c34a0fb8306", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/d05267fd27a5c4f54e06daefa3035995d765ca0c", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/e8675d291ac007e1c636870db880f837a9ea112a", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Primary", "source": "nvd@nist.gov", "description": [{"lang": "en", "value": "NVD-CWE-noinfo"}]}], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/memory-failure: make sure wait for page writeback in memory_failure\n\nOur syzkaller trigger the \"BUG_ON(!list_empty(&inode->i_wb_list))\" in\nclear_inode:\n\n kernel BUG at fs/inode.c:519!\n Internal error: Oops - BUG: 0 [#1] SMP\n Modules linked in:\n Process syz-executor.0 (pid: 249, stack limit = 0x00000000a12409d7)\n CPU: 1 PID: 249 Comm: syz-executor.0 Not tainted 4.19.95\n Hardware name: linux,dummy-virt (DT)\n pstate: 80000005 (Nzcv daif -PAN -UAO)\n pc : clear_inode+0x280/0x2a8\n lr : clear_inode+0x280/0x2a8\n Call trace:\n clear_inode+0x280/0x2a8\n ext4_clear_inode+0x38/0xe8\n ext4_free_inode+0x130/0xc68\n ext4_evict_inode+0xb20/0xcb8\n evict+0x1a8/0x3c0\n iput+0x344/0x460\n do_unlinkat+0x260/0x410\n __arm64_sys_unlinkat+0x6c/0xc0\n el0_svc_common+0xdc/0x3b0\n el0_svc_handler+0xf8/0x160\n el0_svc+0x10/0x218\n Kernel panic - not syncing: Fatal exception\n\nA crash dump of this problem show that someone called __munlock_pagevec\nto clear page LRU without lock_page: do_mmap -> mmap_region -> do_munmap\n-> munlock_vma_pages_range -> __munlock_pagevec.\n\nAs a result memory_failure will call identify_page_state without\nwait_on_page_writeback. And after truncate_error_page clear the mapping\nof this page. end_page_writeback won't call sb_clear_inode_writeback to\nclear inode->i_wb_list. That will trigger BUG_ON in clear_inode!\n\nFix it by checking PageWriteback too to help determine should we skip\nwait_on_page_writeback."}, {"lang": "es", "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: mm/memory-failure: aseg\u00farese de esperar la reescritura de la p\u00e1gina en Memory_failure. Nuestro syzkaller activa el \"BUG_ON(!list_empty(&inode->i_wb_list))\" en clear_inode: kernel BUG en fs /inodo.c:519! Error interno: Oops - BUG: 0 [#1] M\u00f3dulos SMP vinculados en: Proceso syz-executor.0 (pid: 249, l\u00edmite de pila = 0x00000000a12409d7) CPU: 1 PID: 249 Comm: syz-executor.0 No contaminado 4.19. 95 Nombre de hardware: linux,dummy-virt (DT) pstate: 80000005 (Nzcv daif -PAN -UAO) pc: clear_inode+0x280/0x2a8 lr: clear_inode+0x280/0x2a8 Rastreo de llamadas: clear_inode+0x280/0x2a8 ext4_clear_inode+0x38/0xe8 ext4_free_inode+0x130/0xc68 ext4_evict_inode+0xb20/0xcb8 desalojar+0x1a8/0x3c0 iput+0x344/0x460 do_unlinkat+0x260/0x410 __arm64_sys_unlinkat+0x6c/0xc0 el0_svc_common+0xdc /0x3b0 el0_svc_handler+0xf8/0x160 el0_svc+0x10/0x218 P\u00e1nico del kernel: no se sincroniza : Excepci\u00f3n fatal Un volcado de memoria de este problema muestra que alguien llam\u00f3 a __munlock_pagevec para borrar la p\u00e1gina LRU sin lock_page: do_mmap -> mmap_region -> do_munmap -> munlock_vma_pages_range -> __munlock_pagevec. Como resultado, Memory_failure llamar\u00e1 a identify_page_state sin wait_on_page_writeback. Y despu\u00e9s de truncate_error_page, borre el mapeo de esta p\u00e1gina. end_page_writeback no llamar\u00e1 a sb_clear_inode_writeback para borrar inode->i_wb_list. \u00a1Eso activar\u00e1 BUG_ON en clear_inode! Solucionarlo marcando tambi\u00e9n PageWriteback para ayudar a determinar si debemos omitir wait_on_page_writeback."}], "lastModified": "2025-04-30T15:05:57.057", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "CC6F60EE-EF5A-4213-9927-5F26053B4B41", "versionEndExcluding": "4.14.238", "versionStartIncluding": "3.16"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "F3CAB837-7D38-4934-AD4F-195CEFD754E6", "versionEndExcluding": "4.19.196", "versionStartIncluding": "4.15"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "6267BD4E-BE25-48B5-B850-4B493440DAFA", "versionEndExcluding": "5.4.128", "versionStartIncluding": "4.20"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "59455D13-A902-42E1-97F7-5ED579777193", "versionEndExcluding": "5.10.46", "versionStartIncluding": "5.5"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "7806E7E5-6D4F-4E18-81C1-79B3C60EE855", "versionEndExcluding": "5.12.13", "versionStartIncluding": "5.11"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:5.13:rc1:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "0CBAD0FC-C281-4666-AB2F-F8E6E1165DF7"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:5.13:rc2:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "96AC23B2-D46A-49D9-8203-8E1BEDCA8532"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:5.13:rc3:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "DA610E30-717C-4700-9F77-A3C9244F3BFD"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:5.13:rc4:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "1ECD33F5-85BE-430B-8F86-8D7BD560311D"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:5.13:rc5:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "CF351855-2437-4CF5-AD7C-BDFA51F27683"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:5.13:rc6:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "25A855BA-2118-44F2-90EF-EBBB12AF51EF"}], "operator": "OR"}]}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}