CVE-2024-26696
nilfs2: fix hang in nilfs_lookup_dirty_data_buffers()
Severity Score
Exploit Likelihood
Affected Versions
Public Exploits
0Exploited in Wild
-Decision
Descriptions
In the Linux kernel, the following vulnerability has been resolved:
nilfs2: fix hang in nilfs_lookup_dirty_data_buffers()
Syzbot reported a hang issue in migrate_pages_batch() called by mbind()
and nilfs_lookup_dirty_data_buffers() called in the log writer of nilfs2.
While migrate_pages_batch() locks a folio and waits for the writeback to
complete, the log writer thread that should bring the writeback to
completion picks up the folio being written back in
nilfs_lookup_dirty_data_buffers() that it calls for subsequent log
creation and was trying to lock the folio. Thus causing a deadlock.
In the first place, it is unexpected that folios/pages in the middle of
writeback will be updated and become dirty. Nilfs2 adds a checksum to
verify the validity of the log being written and uses it for recovery at
mount, so data changes during writeback are suppressed. Since this is
broken, an unclean shutdown could potentially cause recovery to fail.
Investigation revealed that the root cause is that the wait for writeback
completion in nilfs_page_mkwrite() is conditional, and if the backing
device does not require stable writes, data may be modified without
waiting.
Fix these issues by making nilfs_page_mkwrite() wait for writeback to
finish regardless of the stable write requirement of the backing device.
En el kernel de Linux, se resolvió la siguiente vulnerabilidad: nilfs2: corrige un bloqueo en nilfs_lookup_dirty_data_buffers() Syzbot informó un problema de bloqueo en migrar_pages_batch() llamado por mbind() y nilfs_lookup_dirty_data_buffers() llamado en el escritor de registros de nilfs2. Mientras migrar_pages_batch() bloquea una publicación y espera a que se complete la reescritura, el subproceso del escritor de registros que debería completar la reescritura recoge la publicación que se está reescribiendo en nilfs_lookup_dirty_data_buffers() que solicita la creación de registros posteriores y estaba intentando bloquear la fol. Provocando así un punto muerto. En primer lugar, es inesperado que los folios/páginas en medio de la reescritura se actualicen y se ensucien. Nilfs2 agrega una suma de verificación para verificar la validez del registro que se está escribiendo y la usa para la recuperación en el montaje, de modo que se suprimen los cambios de datos durante la reescritura. Dado que esto no funciona, un cierre incorrecto podría provocar que falle la recuperación. La investigación reveló que la causa principal es que la espera para que se complete la reescritura en nilfs_page_mkwrite() es condicional, y si el dispositivo de respaldo no requiere escrituras estables, los datos se pueden modificar sin esperar. Solucione estos problemas haciendo que nilfs_page_mkwrite() espere a que finalice la reescritura independientemente del requisito de escritura estable del dispositivo de respaldo.
CVSS Scores
SSVC
- Decision:Track
Timeline
- 2024-02-19 CVE Reserved
- 2024-04-03 CVE Published
- 2024-04-04 EPSS Updated
- 2024-09-11 CVE Updated
- ---------- Exploited in Wild
- ---------- KEV Due Date
- ---------- First Exploit
CWE
CAPEC
References (11)
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Affected Vendors, Products, and Versions
| Vendor | Product | Version | Other | Status | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Vendor | Product | Version | Other | Status | <-- --> | Vendor | Product | Version | Other | Status |
| Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 3.9 < 4.19.307 Search vendor "Linux" for product "Linux Kernel" and version " >= 3.9 < 4.19.307" | en |
Affected
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| Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 3.9 < 5.4.269 Search vendor "Linux" for product "Linux Kernel" and version " >= 3.9 < 5.4.269" | en |
Affected
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| Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 3.9 < 5.10.210 Search vendor "Linux" for product "Linux Kernel" and version " >= 3.9 < 5.10.210" | en |
Affected
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| Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 3.9 < 5.15.149 Search vendor "Linux" for product "Linux Kernel" and version " >= 3.9 < 5.15.149" | en |
Affected
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| Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 3.9 < 6.1.79 Search vendor "Linux" for product "Linux Kernel" and version " >= 3.9 < 6.1.79" | en |
Affected
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| Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 3.9 < 6.6.18 Search vendor "Linux" for product "Linux Kernel" and version " >= 3.9 < 6.6.18" | en |
Affected
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| Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 3.9 < 6.7.6 Search vendor "Linux" for product "Linux Kernel" and version " >= 3.9 < 6.7.6" | en |
Affected
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| Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 3.9 < 6.8 Search vendor "Linux" for product "Linux Kernel" and version " >= 3.9 < 6.8" | en |
Affected
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