{"id":"CVE-2024-26956","summary":"nilfs2: fix failure to detect DAT corruption in btree and direct mappings","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnilfs2: fix failure to detect DAT corruption in btree and direct mappings\n\nPatch series \"nilfs2: fix kernel bug at submit_bh_wbc()\".\n\nThis resolves a kernel BUG reported by syzbot.  Since there are two\nflaws involved, I've made each one a separate patch.\n\nThe first patch alone resolves the syzbot-reported bug, but I think\nboth fixes should be sent to stable, so I've tagged them as such.\n\n\nThis patch (of 2):\n\nSyzbot has reported a kernel bug in submit_bh_wbc() when writing file data\nto a nilfs2 file system whose metadata is corrupted.\n\nThere are two flaws involved in this issue.\n\nThe first flaw is that when nilfs_get_block() locates a data block using\nbtree or direct mapping, if the disk address translation routine\nnilfs_dat_translate() fails with internal code -ENOENT due to DAT metadata\ncorruption, it can be passed back to nilfs_get_block().  This causes\nnilfs_get_block() to misidentify an existing block as non-existent,\ncausing both data block lookup and insertion to fail inconsistently.\n\nThe second flaw is that nilfs_get_block() returns a successful status in\nthis inconsistent state.  This causes the caller __block_write_begin_int()\nor others to request a read even though the buffer is not mapped,\nresulting in a BUG_ON check for the BH_Mapped flag in submit_bh_wbc()\nfailing.\n\nThis fixes the first issue by changing the return value to code -EINVAL\nwhen a conversion using DAT fails with code -ENOENT, avoiding the\nconflicting condition that leads to the kernel bug described above.  Here,\ncode -EINVAL indicates that metadata corruption was detected during the\nblock lookup, which will be properly handled as a file system error and\nconverted to -EIO when passing through the nilfs2 bmap layer.","modified":"2026-03-20T12:35:19.507129Z","published":"2024-05-01T05:18:56.101Z","related":["SUSE-SU-2024:1644-1","SUSE-SU-2024:1659-1","SUSE-SU-2024:1663-1","SUSE-SU-2024:2135-1","SUSE-SU-2025:20008-1","SUSE-SU-2025:20028-1"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/26xxx/CVE-2024-26956.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/2e2619ff5d0def4bb6c2037a32a6eaa28dd95c84"},{"type":"WEB","url":"https://git.kernel.org/stable/c/46b832e09d43b394ac0f6d9485d2b1a06593f0b7"},{"type":"WEB","url":"https://git.kernel.org/stable/c/82827ca21e7c8a91384c5baa656f78a5adfa4ab4"},{"type":"WEB","url":"https://git.kernel.org/stable/c/9cbe1ad5f4354f4df1445e5f4883983328cd6d8e"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a8e4d098de1c0f4c5c1f2ed4633a860f0da6d713"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b67189690eb4b7ecc84ae16fa1e880e0123eaa35"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c3b5c5c31e723b568f83d8cafab8629d9d830ffb"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f2f26b4a84a0ef41791bd2d70861c8eac748f4ba"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f69e81396aea66304d214f175aa371f1b5578862"},{"type":"WEB","url":"https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html"},{"type":"WEB","url":"https://lists.debian.org/debian-lts-announce/2024/06/msg00020.html"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/26xxx/CVE-2024-26956.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2024-26956"},{"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":"c3a7abf06ce719a51139e62a034590be99abbc2c"},{"fixed":"b67189690eb4b7ecc84ae16fa1e880e0123eaa35"},{"fixed":"9cbe1ad5f4354f4df1445e5f4883983328cd6d8e"},{"fixed":"c3b5c5c31e723b568f83d8cafab8629d9d830ffb"},{"fixed":"2e2619ff5d0def4bb6c2037a32a6eaa28dd95c84"},{"fixed":"46b832e09d43b394ac0f6d9485d2b1a06593f0b7"},{"fixed":"f69e81396aea66304d214f175aa371f1b5578862"},{"fixed":"a8e4d098de1c0f4c5c1f2ed4633a860f0da6d713"},{"fixed":"82827ca21e7c8a91384c5baa656f78a5adfa4ab4"},{"fixed":"f2f26b4a84a0ef41791bd2d70861c8eac748f4ba"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2024-26956.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:N/I:N/A:H"}]}