CVE-2024-26757
md: Don't ignore read-only array in md_check_recovery()
Severity Score
Exploit Likelihood
Affected Versions
Public Exploits
0Exploited in Wild
-Decision
Descriptions
In the Linux kernel, the following vulnerability has been resolved:
md: Don't ignore read-only array in md_check_recovery()
Usually if the array is not read-write, md_check_recovery() won't
register new sync_thread in the first place. And if the array is
read-write and sync_thread is registered, md_set_readonly() will
unregister sync_thread before setting the array read-only. md/raid
follow this behavior hence there is no problem.
After commit f52f5c71f3d4 ("md: fix stopping sync thread"), following
hang can be triggered by test shell/integrity-caching.sh:
1) array is read-only. dm-raid update super block:
rs_update_sbs
ro = mddev->ro
mddev->ro = 0
-> set array read-write
md_update_sb
2) register new sync thread concurrently.
3) dm-raid set array back to read-only:
rs_update_sbs
mddev->ro = ro
4) stop the array:
raid_dtr
md_stop
stop_sync_thread
set_bit(MD_RECOVERY_INTR, &mddev->recovery);
md_wakeup_thread_directly(mddev->sync_thread);
wait_event(..., !test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
5) sync thread done:
md_do_sync
set_bit(MD_RECOVERY_DONE, &mddev->recovery);
md_wakeup_thread(mddev->thread);
6) daemon thread can't unregister sync thread:
md_check_recovery
if (!md_is_rdwr(mddev) &&
!test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))
return;
-> -> MD_RECOVERY_RUNNING can't be cleared, hence step 4 hang;
The root cause is that dm-raid manipulate 'mddev->ro' by itself,
however, dm-raid really should stop sync thread before setting the
array read-only. Unfortunately, I need to read more code before I
can refacter the handler of 'mddev->ro' in dm-raid, hence let's fix
the problem the easy way for now to prevent dm-raid regression.
En el kernel de Linux, se resolvió la siguiente vulnerabilidad: md: No ignorar la matriz de solo lectura en md_check_recovery() Generalmente, si la matriz no es de lectura y escritura, md_check_recovery() no registrará un nuevo sync_thread en primer lugar. Y si la matriz es de lectura y escritura y sync_thread está registrado, md_set_readonly() cancelará el registro de sync_thread antes de configurar la matriz como de solo lectura. md/raid sigue este comportamiento, por lo que no hay problema. Después de commit f52f5c71f3d4 ("md: arreglar la detención del hilo de sincronización"), el siguiente bloqueo puede activarse mediante test shell/integrity-caching.sh: 1) la matriz es de solo lectura. Superbloque de actualización dm-raid: rs_update_sbs ro = mddev->ro mddev->ro = 0 -> establecer matriz de lectura y escritura md_update_sb 2) registrar un nuevo hilo de sincronización simultáneamente. 3) dm-raid vuelve a configurar la matriz en solo lectura: rs_update_sbs mddev->ro = ro 4) detiene la matriz: raid_dtr md_stop stop_sync_thread set_bit(MD_RECOVERY_INTR, &mddev->recovery); md_wakeup_thread_directly(mddev->sync_thread); wait_event(..., !test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) 5) hilo de sincronización realizado: md_do_sync set_bit(MD_RECOVERY_DONE, &mddev->recovery); md_wakeup_thread(mddev->thread); 6) el hilo del demonio no puede cancelar el registro del hilo de sincronización: md_check_recovery if (!md_is_rdwr(mddev) && !test_bit(MD_RECOVERY_NEEDED, &mddev->recovery)) return; -> -> MD_RECOVERY_RUNNING no se puede borrar, por lo tanto el paso 4 se bloquea; La causa principal es que dm-raid manipula 'mddev->ro' por sí solo; sin embargo, dm-raid realmente debería detener el hilo de sincronización antes de configurar la matriz como de solo lectura. Desafortunadamente, necesito leer más código antes de poder refactorizar el controlador de 'mddev->ro' en dm-raid, por lo tanto, solucionemos el problema de la manera más fácil por ahora para evitar la regresión de dm-raid.
CVSS Scores
SSVC
- Decision:Track
Timeline
- 2024-02-19 CVE Reserved
- 2024-04-03 CVE Published
- 2024-04-04 EPSS Updated
- 2024-12-19 CVE Updated
- ---------- Exploited in Wild
- ---------- KEV Due Date
- ---------- First Exploit
CWE
- CWE-20: Improper Input Validation
- CWE-404: Improper Resource Shutdown or Release
CAPEC
References (5)
URL | Tag | Source |
---|---|---|
https://git.kernel.org/stable/c/ecbfb9f118bce49f571675929160e4ecef91cc8a | Vuln. Introduced |
URL | Date | SRC |
---|
URL | Date | SRC |
---|---|---|
https://git.kernel.org/stable/c/2ea169c5a0b1134d573d07fc27a16f327ad0e7d3 | 2024-03-01 | |
https://git.kernel.org/stable/c/55a48ad2db64737f7ffc0407634218cc6e4c513b | 2024-02-15 |
URL | Date | SRC |
---|---|---|
https://access.redhat.com/security/cve/CVE-2024-26757 | 2024-11-12 | |
https://bugzilla.redhat.com/show_bug.cgi?id=2273208 | 2024-11-12 |
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" | >= 4.8 < 6.7.7 Search vendor "Linux" for product "Linux Kernel" and version " >= 4.8 < 6.7.7" | en |
Affected
| ||||||
Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 4.8 < 6.8 Search vendor "Linux" for product "Linux Kernel" and version " >= 4.8 < 6.8" | en |
Affected
|