{"id":"CVE-2023-53311","summary":"nilfs2: fix use-after-free of nilfs_root in dirtying inodes via iput","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnilfs2: fix use-after-free of nilfs_root in dirtying inodes via iput\n\nDuring unmount process of nilfs2, nothing holds nilfs_root structure after\nnilfs2 detaches its writer in nilfs_detach_log_writer().  Previously,\nnilfs_evict_inode() could cause use-after-free read for nilfs_root if\ninodes are left in \"garbage_list\" and released by nilfs_dispose_list at\nthe end of nilfs_detach_log_writer(), and this bug was fixed by commit\n9b5a04ac3ad9 (\"nilfs2: fix use-after-free bug of nilfs_root in\nnilfs_evict_inode()\").\n\nHowever, it turned out that there is another possibility of UAF in the\ncall path where mark_inode_dirty_sync() is called from iput():\n\nnilfs_detach_log_writer()\n  nilfs_dispose_list()\n    iput()\n      mark_inode_dirty_sync()\n        __mark_inode_dirty()\n          nilfs_dirty_inode()\n            __nilfs_mark_inode_dirty()\n              nilfs_load_inode_block() --\u003e causes UAF of nilfs_root struct\n\nThis can happen after commit 0ae45f63d4ef (\"vfs: add support for a\nlazytime mount option\"), which changed iput() to call\nmark_inode_dirty_sync() on its final reference if i_state has I_DIRTY_TIME\nflag and i_nlink is non-zero.\n\nThis issue appears after commit 28a65b49eb53 (\"nilfs2: do not write dirty\ndata after degenerating to read-only\") when using the syzbot reproducer,\nbut the issue has potentially existed before.\n\nFix this issue by adding a \"purging flag\" to the nilfs structure, setting\nthat flag while disposing the \"garbage_list\" and checking it in\n__nilfs_mark_inode_dirty().\n\nUnlike commit 9b5a04ac3ad9 (\"nilfs2: fix use-after-free bug of nilfs_root\nin nilfs_evict_inode()\"), this patch does not rely on ns_writer to\ndetermine whether to skip operations, so as not to break recovery on\nmount.  The nilfs_salvage_orphan_logs routine dirties the buffer of\nsalvaged data before attaching the log writer, so changing\n__nilfs_mark_inode_dirty() to skip the operation when ns_writer is NULL\nwill cause recovery write to fail.  The purpose of using the cleanup-only\nflag is to allow for narrowing of such conditions.","modified":"2026-04-02T09:43:59.058663Z","published":"2025-09-16T16:11:49.099Z","related":["SUSE-SU-2025:03600-1","SUSE-SU-2025:03615-1","SUSE-SU-2025:03628-1","SUSE-SU-2025:03634-1","SUSE-SU-2025:20851-1","SUSE-SU-2025:20861-1","SUSE-SU-2025:20870-1","SUSE-SU-2025:20898-1","SUSE-SU-2025:3716-1","SUSE-SU-2025:3751-1","SUSE-SU-2025:3761-1","SUSE-SU-2025:4057-1","SUSE-SU-2025:4132-1","SUSE-SU-2025:4141-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/53xxx/CVE-2023-53311.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/11afd67f1b3c28eb216e50a3ca8dbcb69bb71793"},{"type":"WEB","url":"https://git.kernel.org/stable/c/3645510cf926e6af2f4d44899370d7e5331c93bd"},{"type":"WEB","url":"https://git.kernel.org/stable/c/37207240872456fbab44a110bde6640445233963"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5828d5f5dc877dcfdd7b23102e978e2ecfd86d82"},{"type":"WEB","url":"https://git.kernel.org/stable/c/7532ff6edbf5242376b24a95a2fefb59bb653e5a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a3c3b4cbf9b8554120fb230e6516e980c6277487"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d2c539c216cce74837a9cf5804eb205939b82227"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f8654743a0e6909dc634cbfad6db6816f10f3399"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/53xxx/CVE-2023-53311.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2023-53311"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"0ae45f63d4ef8d8eeec49c7d8b44a1775fff13e8"},{"fixed":"11afd67f1b3c28eb216e50a3ca8dbcb69bb71793"},{"fixed":"a3c3b4cbf9b8554120fb230e6516e980c6277487"},{"fixed":"d2c539c216cce74837a9cf5804eb205939b82227"},{"fixed":"37207240872456fbab44a110bde6640445233963"},{"fixed":"3645510cf926e6af2f4d44899370d7e5331c93bd"},{"fixed":"7532ff6edbf5242376b24a95a2fefb59bb653e5a"},{"fixed":"5828d5f5dc877dcfdd7b23102e978e2ecfd86d82"},{"fixed":"f8654743a0e6909dc634cbfad6db6816f10f3399"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-53311.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}]}