CVE-2024-47679

{"id": "CVE-2024-47679", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Primary", "source": "[email protected]", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 4.7, "attackVector": "LOCAL", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "HIGH", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 1.0}]}, "published": "2024-10-21T12:15:04.920", "references": [{"url": "https://git.kernel.org/stable/c/0eed942bc65de1f93eca7bda51344290f9c573bb", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/0f8a5b6d0dafa4f533ac82e98f8b812073a7c9d1", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/3721a69403291e2514d13a7c3af50a006ea1153b", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/47a68c75052a660e4c37de41e321582ec9496195", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/489faddb1ae75b0e1a741fe5ca2542a2b5e794a5", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/540fb13120c9eab3ef203f90c00c8e69f37449d1", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/6c857fb12b9137fee574443385d53914356bbe11", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/6cc13a80a26e6b48f78c725c01b91987d61563ef", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/88b1afbf0f6b221f6c5bb66cc80cd3b38d696687", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html", "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html", "source": "af854a3a-2127-422b-91ae-364da2661108"}], "vulnStatus": "Modified", "weaknesses": [{"type": "Primary", "source": "[email protected]", "description": [{"lang": "en", "value": "CWE-362"}]}], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvfs: fix race between evice_inodes() and find_inode()&iput()\n\nHi, all\n\nRecently I noticed a bug[1] in btrfs, after digged it into\nand I believe it'a race in vfs.\n\nLet's assume there's a inode (ie ino 261) with i_count 1 is\ncalled by iput(), and there's a concurrent thread calling\ngeneric_shutdown_super().\n\ncpu0: cpu1:\niput() // i_count is 1\n ->spin_lock(inode)\n ->dec i_count to 0\n ->iput_final() generic_shutdown_super()\n ->__inode_add_lru() ->evict_inodes()\n // cause some reason[2] ->if (atomic_read(inode->i_count)) continue;\n // return before // inode 261 passed the above check\n // list_lru_add_obj() // and then schedule out\n ->spin_unlock()\n// note here: the inode 261\n// was still at sb list and hash list,\n// and I_FREEING|I_WILL_FREE was not been set\n\nbtrfs_iget()\n // after some function calls\n ->find_inode()\n // found the above inode 261\n ->spin_lock(inode)\n // check I_FREEING|I_WILL_FREE\n // and passed\n ->__iget()\n ->spin_unlock(inode) // schedule back\n ->spin_lock(inode)\n // check (I_NEW|I_FREEING|I_WILL_FREE) flags,\n // passed and set I_FREEING\niput() ->spin_unlock(inode)\n ->spin_lock(inode)\t\t\t ->evict()\n // dec i_count to 0\n ->iput_final()\n ->spin_unlock()\n ->evict()\n\nNow, we have two threads simultaneously evicting\nthe same inode, which may trigger the BUG(inode->i_state & I_CLEAR)\nstatement both within clear_inode() and iput().\n\nTo fix the bug, recheck the inode->i_count after holding i_lock.\nBecause in the most scenarios, the first check is valid, and\nthe overhead of spin_lock() can be reduced.\n\nIf there is any misunderstanding, please let me know, thanks.\n\n[1]: https://lore.kernel.org/linux-btrfs/[email protected]/\n[2]: The reason might be 1. SB_ACTIVE was removed or 2. mapping_shrinkable()\nreturn false when I reproduced the bug."}, {"lang": "es", "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: vfs: arregla la ejecuci\u00f3n entre evice_inodes() y find_inode()&iput() Hola a todos Recientemente not\u00e9 un error[1] en btrfs, despu\u00e9s de investigarlo y creo que es una ejecuci\u00f3n en vfs. Supongamos que hay un inodo (es decir, ino 261) con i_count 1 que es llamado por iput(), y hay un hilo concurrente que llama a generic_shutdown_super(). cpu0: cpu1: iput() // i_count es 1 ->spin_lock(inode) ->dec i_count a 0 ->iput_final() generic_shutdown_super() ->__inode_add_lru() ->evict_inodes() // por alguna raz\u00f3n[2] ->if (atomic_read(inode->i_count)) continue; // regresar antes // el inodo 261 pas\u00f3 la verificaci\u00f3n anterior // list_lru_add_obj() // y luego programar la salida ->spin_unlock() // nota aqu\u00ed: el inodo 261 // todav\u00eda estaba en la lista sb y la lista hash, // y I_FREEING|I_WILL_FREE no se hab\u00eda establecido btrfs_iget() // despu\u00e9s de algunas llamadas de funci\u00f3n ->find_inode() // encontr\u00f3 el inodo 261 anterior ->spin_lock(inode) // verific\u00f3 I_FREEING|I_WILL_FREE // y pas\u00f3 ->__iget() ->spin_unlock(inode) // program\u00f3 de regreso ->spin_lock(inode) // verific\u00f3 los indicadores (I_NEW|I_FREEING|I_WILL_FREE), // pas\u00f3 y estableci\u00f3 I_FREEING iput() ->spin_unlock(inode) ->spin_lock(inode) ->evict() // dec i_count a 0 ->iput_final() ->spin_unlock() ->evict() Ahora, tenemos dos subprocesos expulsando simult\u00e1neamente el mismo inodo, lo que puede activar la declaraci\u00f3n BUG(inode->i_state & I_CLEAR) tanto dentro de clear_inode() como de iput(). Para corregir el error, vuelva a verificar inode->i_count despu\u00e9s de mantener i_lock. Porque en la mayor\u00eda de los escenarios, la primera verificaci\u00f3n es v\u00e1lida y se puede reducir la sobrecarga de spin_lock(). Si hay alg\u00fan malentendido, h\u00e1gamelo saber, gracias. [1]: https://lore.kernel.org/linux-btrfs/[email protected]/ [2]: La raz\u00f3n podr\u00eda ser 1. SB_ACTIVE fue eliminado o 2. mapping_shrinkable() devolvi\u00f3 falso cuando reproduje el error."}], "lastModified": "2025-11-03T23:16:15.737", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "205A6F87-4258-4528-8078-AC66AD2A7B07", "versionEndExcluding": "5.10.227", "versionStartIncluding": "2.6.37"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "4D51C05D-455B-4D8D-89E7-A58E140B864C", "versionEndExcluding": "5.15.168", "versionStartIncluding": "5.11"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "D01BD22E-ACD1-4618-9D01-6116570BE1EE", "versionEndExcluding": "6.1.113", "versionStartIncluding": "5.16"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "D448821D-C085-4CAF-88FA-2DDE7BE21976", "versionEndExcluding": "6.6.54", "versionStartIncluding": "6.2"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "CE94BB8D-B0AB-4563-9ED7-A12122B56EBE", "versionEndExcluding": "6.10.13", "versionStartIncluding": "6.7"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "AB755D26-97F4-43B6-8604-CD076811E181", "versionEndExcluding": "6.11.2", "versionStartIncluding": "6.11"}], "operator": "OR"}]}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}