CVE-2024-42256

{"id": "CVE-2024-42256", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 9.8, "attackVector": "NETWORK", "baseSeverity": "CRITICAL", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "HIGH"}, "impactScore": 5.9, "exploitabilityScore": 3.9}]}, "published": "2024-08-08T09:15:08.553", "references": [{"url": "https://git.kernel.org/stable/c/b1d0a566769b6fb3795b5289fc1daf9e0638d97a", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/de40579b903883274fe203865f29d66b168b7236", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "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\ncifs: Fix server re-repick on subrequest retry\n\nWhen a subrequest is marked for needing retry, netfs will call\ncifs_prepare_write() which will make cifs repick the server for the op\nbefore renegotiating credits; it then calls cifs_issue_write() which\ninvokes smb2_async_writev() - which re-repicks the server.\n\nIf a different server is then selected, this causes the increment of\nserver->in_flight to happen against one record and the decrement to happen\nagainst another, leading to misaccounting.\n\nFix this by just removing the repick code in smb2_async_writev(). As this\nis only called from netfslib-driven code, cifs_prepare_write() should\nalways have been called first, and so server should never be NULL and the\npreparatory step is repeated in the event that we do a retry.\n\nThe problem manifests as a warning looking something like:\n\n WARNING: CPU: 4 PID: 72896 at fs/smb/client/smb2ops.c:97 smb2_add_credits+0x3f0/0x9e0 [cifs]\n ...\n RIP: 0010:smb2_add_credits+0x3f0/0x9e0 [cifs]\n ...\n smb2_writev_callback+0x334/0x560 [cifs]\n cifs_demultiplex_thread+0x77a/0x11b0 [cifs]\n kthread+0x187/0x1d0\n ret_from_fork+0x34/0x60\n ret_from_fork_asm+0x1a/0x30\n\nWhich may be triggered by a number of different xfstests running against an\nAzure server in multichannel mode. generic/249 seems the most repeatable,\nbut generic/215, generic/249 and generic/308 may also show it."}, {"lang": "es", "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: cifs: corrige la repetici\u00f3n del servidor en el reintento de subrequest Cuando se marca una subrequest para necesitar un reintento, netfs llamar\u00e1 a cifs_prepare_write(), lo que har\u00e1 que cifs vuelva a seleccionar el servidor para la operaci\u00f3n antes de renegociar los cr\u00e9ditos; luego llama a cifs_issue_write(), que invoca a smb2_async_writev(), que vuelve a seleccionar el servidor. Si luego se selecciona un servidor diferente, esto hace que el incremento de server->in_flight ocurra en un registro y la disminuci\u00f3n en otro, lo que lleva a una contabilidad err\u00f3nea. Solucione este problema simplemente eliminando el c\u00f3digo de repetici\u00f3n en smb2_async_writev(). Como esto solo se llama desde c\u00f3digo controlado por netfslib, siempre se deber\u00eda haber llamado primero a cifs_prepare_write(), por lo que el servidor nunca deber\u00eda ser NULL y el paso preparatorio se repite en caso de que hagamos un reintento. El problema se manifiesta como una advertencia similar a: ADVERTENCIA: CPU: 4 PID: 72896 en fs/smb/client/smb2ops.c:97 smb2_add_credits+0x3f0/0x9e0 [cifs] ... RIP: 0010:smb2_add_credits+0x3f0/0x9e0 [cifs] ... smb2_writev_callback+0x334/0x560 [cifs] cifs_demultiplex_thread+0x77a/0x11b0 [cifs] kthread+0x187/0x1d0 ret_from_fork+0x34/0x60 ret_from_fork_asm+0x1a/0x30 Que puede ser activado por varios xfstests corriendo contra un Servidor Azure en modo multicanal. generic/249 parece el m\u00e1s repetible, pero generic/215, generic/249 y generic/308 tambi\u00e9n pueden mostrarlo."}], "lastModified": "2024-09-06T13:56:00.207", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "CC5B6890-A2E7-41F8-AA56-E3202E9FB075", "versionEndExcluding": "6.10.1", "versionStartIncluding": "6.10"}], "operator": "OR"}]}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}