ghsa-m9fq-g2m8-9p75
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
ext4: only dirty folios when data journaling regular files
fstest generic/388 occasionally reproduces a crash that looks as follows:
BUG: kernel NULL pointer dereference, address: 0000000000000000 ... Call Trace: ext4_block_zero_page_range+0x30c/0x380 [ext4] ext4_truncate+0x436/0x440 [ext4] ext4_process_orphan+0x5d/0x110 [ext4] ext4_orphan_cleanup+0x124/0x4f0 [ext4] ext4_fill_super+0x262d/0x3110 [ext4] get_tree_bdev_flags+0x132/0x1d0 vfs_get_tree+0x26/0xd0 vfs_cmd_create+0x59/0xe0 __do_sys_fsconfig+0x4ed/0x6b0 do_syscall_64+0x82/0x170 ...
This occurs when processing a symlink inode from the orphan list. The partial block zeroing code in the truncate path calls ext4_dirty_journalled_data() -> folio_mark_dirty(). The latter calls mapping->a_ops->dirty_folio(), but symlink inodes are not assigned an a_ops vector in ext4, hence the crash.
To avoid this problem, update the ext4_dirty_journalled_data() helper to only mark the folio dirty on regular files (for which a_ops is assigned). This also matches the journaling logic in the ext4_symlink() creation path, where ext4_handle_dirty_metadata() is called directly.
{
"affected": [],
"aliases": [
"CVE-2025-38220"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-07-04T14:15:30Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: only dirty folios when data journaling regular files\n\nfstest generic/388 occasionally reproduces a crash that looks as\nfollows:\n\nBUG: kernel NULL pointer dereference, address: 0000000000000000\n...\nCall Trace:\n \u003cTASK\u003e\n ext4_block_zero_page_range+0x30c/0x380 [ext4]\n ext4_truncate+0x436/0x440 [ext4]\n ext4_process_orphan+0x5d/0x110 [ext4]\n ext4_orphan_cleanup+0x124/0x4f0 [ext4]\n ext4_fill_super+0x262d/0x3110 [ext4]\n get_tree_bdev_flags+0x132/0x1d0\n vfs_get_tree+0x26/0xd0\n vfs_cmd_create+0x59/0xe0\n __do_sys_fsconfig+0x4ed/0x6b0\n do_syscall_64+0x82/0x170\n ...\n\nThis occurs when processing a symlink inode from the orphan list. The\npartial block zeroing code in the truncate path calls\next4_dirty_journalled_data() -\u003e folio_mark_dirty(). The latter calls\nmapping-\u003ea_ops-\u003edirty_folio(), but symlink inodes are not assigned an\na_ops vector in ext4, hence the crash.\n\nTo avoid this problem, update the ext4_dirty_journalled_data() helper to\nonly mark the folio dirty on regular files (for which a_ops is\nassigned). This also matches the journaling logic in the ext4_symlink()\ncreation path, where ext4_handle_dirty_metadata() is called directly.",
"id": "GHSA-m9fq-g2m8-9p75",
"modified": "2025-07-04T15:31:10Z",
"published": "2025-07-04T15:31:10Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-38220"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/be5f3061a6f904e3674257879e71881ceee5b673"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/cf6a4c4ac7b6e3214f25df594c9689a62f1bb456"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d7af6eee8cd60f55aa8c5fe2b91f11ec0c9a0f27"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e26268ff1dcae5662c1b96c35f18cfa6ab73d9de"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
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