CVE-2024-26868

{"id": "CVE-2024-26868", "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": "2024-04-17T11:15:09.360", "references": [{"url": "https://git.kernel.org/stable/c/31db25e3141b20e2a76a9f219eeca52e3cab126c", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/5ada9016b1217498fad876a3d5b07645cc955608", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/719fcafe07c12646691bd62d7f8d94d657fa0766", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/7ca651b4ec4a049f5a46a0e5ff921b86b91c47c5", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/dac068f164ad05b35e7c0be13f138c3f6adca58f", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/31db25e3141b20e2a76a9f219eeca52e3cab126c", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/5ada9016b1217498fad876a3d5b07645cc955608", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/719fcafe07c12646691bd62d7f8d94d657fa0766", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/7ca651b4ec4a049f5a46a0e5ff921b86b91c47c5", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/dac068f164ad05b35e7c0be13f138c3f6adca58f", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Primary", "source": "nvd@nist.gov", "description": [{"lang": "en", "value": "CWE-476"}]}], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfs: fix panic when nfs4_ff_layout_prepare_ds() fails\n\nWe've been seeing the following panic in production\n\nBUG: kernel NULL pointer dereference, address: 0000000000000065\nPGD 2f485f067 P4D 2f485f067 PUD 2cc5d8067 PMD 0\nRIP: 0010:ff_layout_cancel_io+0x3a/0x90 [nfs_layout_flexfiles]\nCall Trace:\n <TASK>\n ? __die+0x78/0xc0\n ? page_fault_oops+0x286/0x380\n ? __rpc_execute+0x2c3/0x470 [sunrpc]\n ? rpc_new_task+0x42/0x1c0 [sunrpc]\n ? exc_page_fault+0x5d/0x110\n ? asm_exc_page_fault+0x22/0x30\n ? ff_layout_free_layoutreturn+0x110/0x110 [nfs_layout_flexfiles]\n ? ff_layout_cancel_io+0x3a/0x90 [nfs_layout_flexfiles]\n ? ff_layout_cancel_io+0x6f/0x90 [nfs_layout_flexfiles]\n pnfs_mark_matching_lsegs_return+0x1b0/0x360 [nfsv4]\n pnfs_error_mark_layout_for_return+0x9e/0x110 [nfsv4]\n ? ff_layout_send_layouterror+0x50/0x160 [nfs_layout_flexfiles]\n nfs4_ff_layout_prepare_ds+0x11f/0x290 [nfs_layout_flexfiles]\n ff_layout_pg_init_write+0xf0/0x1f0 [nfs_layout_flexfiles]\n __nfs_pageio_add_request+0x154/0x6c0 [nfs]\n nfs_pageio_add_request+0x26b/0x380 [nfs]\n nfs_do_writepage+0x111/0x1e0 [nfs]\n nfs_writepages_callback+0xf/0x30 [nfs]\n write_cache_pages+0x17f/0x380\n ? nfs_pageio_init_write+0x50/0x50 [nfs]\n ? nfs_writepages+0x6d/0x210 [nfs]\n ? nfs_writepages+0x6d/0x210 [nfs]\n nfs_writepages+0x125/0x210 [nfs]\n do_writepages+0x67/0x220\n ? generic_perform_write+0x14b/0x210\n filemap_fdatawrite_wbc+0x5b/0x80\n file_write_and_wait_range+0x6d/0xc0\n nfs_file_fsync+0x81/0x170 [nfs]\n ? nfs_file_mmap+0x60/0x60 [nfs]\n __x64_sys_fsync+0x53/0x90\n do_syscall_64+0x3d/0x90\n entry_SYSCALL_64_after_hwframe+0x46/0xb0\n\nInspecting the core with drgn I was able to pull this\n\n >>> prog.crashed_thread().stack_trace()[0]\n #0 at 0xffffffffa079657a (ff_layout_cancel_io+0x3a/0x84) in ff_layout_cancel_io at fs/nfs/flexfilelayout/flexfilelayout.c:2021:27\n >>> prog.crashed_thread().stack_trace()[0]['idx']\n (u32)1\n >>> prog.crashed_thread().stack_trace()[0]['flseg'].mirror_array[1].mirror_ds\n (struct nfs4_ff_layout_ds *)0xffffffffffffffed\n\nThis is clear from the stack trace, we call nfs4_ff_layout_prepare_ds()\nwhich could error out initializing the mirror_ds, and then we go to\nclean it all up and our check is only for if (!mirror->mirror_ds). This\nis inconsistent with the rest of the users of mirror_ds, which have\n\n if (IS_ERR_OR_NULL(mirror_ds))\n\nto keep from tripping over this exact scenario. Fix this up in\nff_layout_cancel_io() to make sure we don't panic when we get an error.\nI also spot checked all the other instances of checking mirror_ds and we\nappear to be doing the correct checks everywhere, only unconditionally\ndereferencing mirror_ds when we know it would be valid."}, {"lang": "es", "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: nfs: soluciona el p\u00e1nico cuando falla nfs4_ff_layout_prepare_ds() Hemos estado viendo el siguiente error de p\u00e1nico en producci\u00f3n: desreferencia del puntero NULL del kernel, direcci\u00f3n: 0000000000000065 PGD 2f485f067 P4D 2f485f067 PUD 2cc5d8067 PMD RIP : 0010:ff_layout_cancel_io+0x3a/0x90 [nfs_layout_flexfiles] Seguimiento de llamadas: ? __die+0x78/0xc0 ? page_fault_oops+0x286/0x380? __rpc_execute+0x2c3/0x470 [sunrpc] ? rpc_new_task+0x42/0x1c0 [sunrpc] ? exc_page_fault+0x5d/0x110? asm_exc_page_fault+0x22/0x30? ff_layout_free_layoutreturn+0x110/0x110 [nfs_layout_flexfiles]? ff_layout_cancel_io+0x3a/0x90 [nfs_layout_flexfiles]? ff_layout_cancel_io+0x6f/0x90 [nfs_layout_flexfiles] pnfs_mark_matching_lsegs_return+0x1b0/0x360 [nfsv4] pnfs_error_mark_layout_for_return+0x9e/0x110 [nfsv4] ? ff_layout_send_layouterror+0x50/0x160 [nfs_layout_flexfiles] nfs4_ff_layout_prepare_ds+0x11f/0x290 [nfs_layout_flexfiles] ff_layout_pg_init_write+0xf0/0x1f0 [nfs_layout_flexfiles] __nfs_pageio_add_re b\u00fasqueda+0x154/0x6c0 [nfs] nfs_pageio_add_request+0x26b/0x380 [nfs] nfs_do_writepage+0x111/0x1e0 [nfs] nfs_writepages_callback+ 0xf/0x30 [nfs] write_cache_pages+0x17f/0x380 ? nfs_pageio_init_write+0x50/0x50 [nfs] ? nfs_writepages+0x6d/0x210 [nfs]? nfs_writepages+0x6d/0x210 [nfs] nfs_writepages+0x125/0x210 [nfs] do_writepages+0x67/0x220? generic_perform_write+0x14b/0x210 filemap_fdatawrite_wbc+0x5b/0x80 file_write_and_wait_range+0x6d/0xc0 nfs_file_fsync+0x81/0x170 [nfs] ? nfs_file_mmap+0x60/0x60 [nfs] __x64_sys_fsync+0x53/0x90 do_syscall_64+0x3d/0x90 Entry_SYSCALL_64_after_hwframe+0x46/0xb0 Inspeccionando el n\u00facleo con drgn pude extraer esto &gt;&gt;&gt; prog.crashed_thread().stack_trace()[0 ] # 0 en 0xffffffffa079657a (ff_layout_cancel_io+0x3a/0x84) en ff_layout_cancel_io en fs/nfs/flexfilelayout/flexfilelayout.c:2021:27 &gt;&gt;&gt; prog.crashed_thread().stack_trace()[0]['idx'] (u32)1 &gt;&gt;&gt; prog.crashed_thread().stack_trace()[0]['flseg'].mirror_array[1].mirror_ds (struct nfs4_ff_layout_ds *)0xffffffffffffffed Esto queda claro en el seguimiento de la pila, llamamos a nfs4_ff_layout_prepare_ds(), lo que podr\u00eda generar un error inicializando mirror_ds, y luego vamos a limpiarlo todo y nuestra verificaci\u00f3n es solo para if (!mirror-&gt;mirror_ds). Esto es inconsistente con el resto de usuarios de mirror_ds, que tienen if (IS_ERR_OR_NULL(mirror_ds)) para evitar tropezar con este escenario exacto. Solucione esto en ff_layout_cancel_io() para asegurarnos de que no entremos en p\u00e1nico cuando recibamos un error. Tambi\u00e9n revis\u00e9 todas las dem\u00e1s instancias de verificaci\u00f3n de mirror_ds y parece que estamos haciendo las verificaciones correctas en todas partes, solo desreferenciando incondicionalmente mirror_ds cuando sabemos que ser\u00eda v\u00e1lido."}], "lastModified": "2025-01-14T14:45:52.020", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "3057E4AB-0FB4-49B3-B63D-10D187B96B1B", "versionEndExcluding": "6.1.83", "versionStartIncluding": "6.1"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "E00814DC-0BA7-431A-9926-80FEB4A96C68", "versionEndExcluding": "6.6.23", "versionStartIncluding": "6.2"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "9B95D3A6-E162-47D5-ABFC-F3FA74FA7CFD", "versionEndExcluding": "6.7.11", "versionStartIncluding": "6.7"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "543A75FF-25B8-4046-A514-1EA8EDD87AB1", "versionEndExcluding": "6.8.2", "versionStartIncluding": "6.8"}], "operator": "OR"}]}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}