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CVE-2025-38220 (GCVE-0-2025-38220)

Vulnerability from cvelistv5 – Published: 2025-07-04 13:37 – Updated: 2026-05-11 21:23
VLAI
Title
ext4: only dirty folios when data journaling regular files
Summary
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: <TASK> 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.
Severity
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: d84c9ebdac1e39bc7b036c0c829ee8c1956edabc , < cf6a4c4ac7b6e3214f25df594c9689a62f1bb456 (git)
Affected: d84c9ebdac1e39bc7b036c0c829ee8c1956edabc , < be5f3061a6f904e3674257879e71881ceee5b673 (git)
Affected: d84c9ebdac1e39bc7b036c0c829ee8c1956edabc , < d7af6eee8cd60f55aa8c5fe2b91f11ec0c9a0f27 (git)
Affected: d84c9ebdac1e39bc7b036c0c829ee8c1956edabc , < e26268ff1dcae5662c1b96c35f18cfa6ab73d9de (git)
guessed Create a notification for this product.
Linux Linux Affected: 6.4
Unaffected: 0 , < 6.4 (semver)
Unaffected: 6.6.95 , ≤ 6.6.* (semver)
Unaffected: 6.12.35 , ≤ 6.12.* (semver)
Unaffected: 6.15.4 , ≤ 6.15.* (semver)
Unaffected: 6.16 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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            "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: ext4: solo folios sucios cuando se registran datos de archivos normales fstest generic/388 ocasionalmente reproduce un fallo que se parece a lo siguiente: ERROR: desreferencia de puntero NULL del kernel, direcci\u00f3n: 0000000000000000 ... Seguimiento de llamadas: 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 ... Esto ocurre al procesar un inodo de enlace simb\u00f3lico de la lista de hu\u00e9rfanos. El c\u00f3digo de puesta a cero parcial de bloques en la ruta de truncamiento llama a ext4_dirty_journalled_data() -\u0026gt; folio_mark_dirty(). Este \u00faltimo llama a mapping-\u0026gt;a_ops-\u0026gt;dirty_folio(), pero los inodos de enlace simb\u00f3lico no tienen asignado un vector a_ops en ext4, lo que explica el fallo. Para evitar este problema, actualice el asistente ext4_dirty_journalled_data() para que solo marque el folio como sucio en archivos normales (para los que se asigna a_ops). Esto tambi\u00e9n coincide con la l\u00f3gica de registro en la ruta de creaci\u00f3n de ext4_symlink(), donde se llama directamente a ext4_handle_dirty_metadata()."
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}



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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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