// For flags

CVE-2022-48649

mm/slab_common: fix possible double free of kmem_cache

Severity Score

"-"
*CVSS v-

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

Track
*SSVC
Descriptions

In the Linux kernel, the following vulnerability has been resolved:

mm/slab_common: fix possible double free of kmem_cache

When doing slub_debug test, kfence's 'test_memcache_typesafe_by_rcu'
kunit test case cause a use-after-free error:

BUG: KASAN: use-after-free in kobject_del+0x14/0x30
Read of size 8 at addr ffff888007679090 by task kunit_try_catch/261

CPU: 1 PID: 261 Comm: kunit_try_catch Tainted: G B N 6.0.0-rc5-next-20220916 #17
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0x34/0x48
print_address_description.constprop.0+0x87/0x2a5
print_report+0x103/0x1ed
kasan_report+0xb7/0x140
kobject_del+0x14/0x30
kmem_cache_destroy+0x130/0x170
test_exit+0x1a/0x30
kunit_try_run_case+0xad/0xc0
kunit_generic_run_threadfn_adapter+0x26/0x50
kthread+0x17b/0x1b0
</TASK>

The cause is inside kmem_cache_destroy():

kmem_cache_destroy
acquire lock/mutex
shutdown_cache
schedule_work(kmem_cache_release) (if RCU flag set)
release lock/mutex
kmem_cache_release (if RCU flag not set)

In some certain timing, the scheduled work could be run before
the next RCU flag checking, which can then get a wrong value
and lead to double kmem_cache_release().

Fix it by caching the RCU flag inside protected area, just like 'refcnt'

En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: mm/slab_common: corrección posible doble liberación de kmem_cache Al realizar la prueba slub_debug, el caso de prueba kunit 'test_memcache_typesafe_by_rcu' de kfence causa un error de use-after-free: ERROR: KASAN: uso después -free en kobject_del+0x14/0x30 Lectura de tamaño 8 en addr ffff888007679090 por tarea kunit_try_catch/261 CPU: 1 PID: 261 Comm: kunit_try_catch Contaminado: GBN 6.0.0-rc5-next-20220916 #17 Nombre de hardware: PC estándar QEMU ( I440FX+PIIX, 1996), BIOS 1.15.0-1 04/01/2014 TRACE DE LLAMADA: dump_stack_lvl+0x34/0x48 print_address_description.constprop.0+0x87/0x2a5 print_rePort+0x103/0x1ed kasan_report+0xb7/0x140/0x140/0x140+0xb7/0x140/0x140/0x140/0x14/0x140/0xil 0x14/0x30 kmem_cache_destroy+0x130/0x170 test_exit+0x1a/0x30 kunit_try_run_case+0xad/0xc0 kunit_generic_run_threadfn_adapter+0x26/0x50 kthread+0x17b/0x1b0 La causa está dentro de kmem_cache_destroy (): kmem_cache_destroy adquirir bloqueo/mutex Shutdown_cache Schedule_work(kmem_cache_release) (si el indicador RCU está establecido) liberar bloqueo/mutex kmem_cache_release (si el indicador RCU no está establecido) En un momento determinado, el trabajo programado podría ejecutarse antes de la siguiente verificación del indicador RCU, lo que luego puede obtener un valor incorrecto y provocar un doble kmem_cache_release() . Solucionarlo almacenando en caché la bandera RCU dentro del área protegida, como 'refcnt'

*Credits: N/A
CVSS Scores
Attack Vector
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Attack Complexity
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Privileges Required
-
User Interaction
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Scope
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Confidentiality
-
Integrity
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Availability
-
* Common Vulnerability Scoring System
SSVC
  • Decision:Track
Exploitation
None
Automatable
No
Tech. Impact
Partial
* Organization's Worst-case Scenario
Timeline
  • 2024-02-25 CVE Reserved
  • 2024-04-28 CVE Published
  • 2024-04-29 EPSS Updated
  • 2024-09-11 CVE Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
CAPEC
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"
 >= 5.19.8 < 5.19.12
Search vendor "Linux" for product "Linux Kernel" and version " >= 5.19.8 < 5.19.12"
en
Affected