// For flags

CVE-2023-52849

cxl/mem: Fix shutdown order

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:

cxl/mem: Fix shutdown order

Ira reports that removing cxl_mock_mem causes a crash with the following
trace:

BUG: kernel NULL pointer dereference, address: 0000000000000044
[..]
RIP: 0010:cxl_region_decode_reset+0x7f/0x180 [cxl_core]
[..]
Call Trace:
<TASK>
cxl_region_detach+0xe8/0x210 [cxl_core]
cxl_decoder_kill_region+0x27/0x40 [cxl_core]
cxld_unregister+0x29/0x40 [cxl_core]
devres_release_all+0xb8/0x110
device_unbind_cleanup+0xe/0x70
device_release_driver_internal+0x1d2/0x210
bus_remove_device+0xd7/0x150
device_del+0x155/0x3e0
device_unregister+0x13/0x60
devm_release_action+0x4d/0x90
? __pfx_unregister_port+0x10/0x10 [cxl_core]
delete_endpoint+0x121/0x130 [cxl_core]
devres_release_all+0xb8/0x110
device_unbind_cleanup+0xe/0x70
device_release_driver_internal+0x1d2/0x210
bus_remove_device+0xd7/0x150
device_del+0x155/0x3e0
? lock_release+0x142/0x290
cdev_device_del+0x15/0x50
cxl_memdev_unregister+0x54/0x70 [cxl_core]

This crash is due to the clearing out the cxl_memdev's driver context
(@cxlds) before the subsystem is done with it. This is ultimately due to
the region(s), that this memdev is a member, being torn down and expecting
to be able to de-reference @cxlds, like here:

static int cxl_region_decode_reset(struct cxl_region *cxlr, int count)
...
if (cxlds->rcd)
goto endpoint_reset;
...

Fix it by keeping the driver context valid until memdev-device
unregistration, and subsequently the entire stack of related
dependencies, unwinds.

En el kernel de Linux, se resolvió la siguiente vulnerabilidad: cxl/mem: arreglo del orden de apagado. Ira informa que la eliminación de cxl_mock_mem causa un bloqueo con el siguiente rastro: ERROR: desreferencia del puntero NULL del kernel, dirección: 0000000000000044 [..] RIP: 0010: cxl_region_decode_reset+0x7f/0x180 [cxl_core] [..] Seguimiento de llamadas: cxl_region_detach+0xe8/0x210 [cxl_core] cxl_decoder_kill_region+0x27/0x40 [cxl_core] cxld_unregister+0x29/0x40 [cxl_core] 0x110 device_unbind_cleanup+0xe/0x70 device_release_driver_internal+0x1d2/0x210 bus_remove_device+0xd7/0x150 dispositivo_del+0x155/0x3e0 device_unregister+0x13/0x60 devm_release_action+0x4d/0x90 ? __pfx_unregister_port+0x10/0x10 [cxl_core] delete_endpoint+0x121/0x130 [cxl_core] devres_release_all+0xb8/0x110 device_unbind_cleanup+0xe/0x70 dispositivo_release_driver_internal+0x1d2/0x210 bus_remove_device+0xd7/0x15 0 dispositivo_del+0x155/0x3e0? lock_release+0x142/0x290 cdev_device_del+0x15/0x50 cxl_memdev_unregister+0x54/0x70 [cxl_core] Este bloqueo se debe a que se borró el contexto del controlador de cxl_memdev (@cxlds) antes de que el subsistema termine con él. En última instancia, esto se debe a que las regiones de las que este memdev es miembro están siendo derribadas y esperan poder eliminar la referencia a @cxlds, como aquí: static int cxl_region_decode_reset(struct cxl_region *cxlr, int count) .. si (cxlds-&gt;rcd) pasa a endpoint_reset; ... Solucionelo manteniendo válido el contexto del controlador hasta que se cancele el registro del dispositivo memdev y, posteriormente, toda la pila de dependencias relacionadas.

*Credits: N/A
CVSS Scores
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* Common Vulnerability Scoring System
SSVC
  • Decision:Track
Exploitation
None
Automatable
No
Tech. Impact
Partial
* Organization's Worst-case Scenario
Timeline
  • 2024-05-21 CVE Reserved
  • 2024-05-21 CVE Published
  • 2024-05-22 EPSS Updated
  • 2024-12-19 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"
>= 5.15 < 5.15.139
Search vendor "Linux" for product "Linux Kernel" and version " >= 5.15 < 5.15.139"
en
Affected
Linux
Search vendor "Linux"
Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
>= 5.15 < 6.1.63
Search vendor "Linux" for product "Linux Kernel" and version " >= 5.15 < 6.1.63"
en
Affected
Linux
Search vendor "Linux"
Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
>= 5.15 < 6.5.12
Search vendor "Linux" for product "Linux Kernel" and version " >= 5.15 < 6.5.12"
en
Affected
Linux
Search vendor "Linux"
Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
>= 5.15 < 6.6.2
Search vendor "Linux" for product "Linux Kernel" and version " >= 5.15 < 6.6.2"
en
Affected
Linux
Search vendor "Linux"
Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
>= 5.15 < 6.7
Search vendor "Linux" for product "Linux Kernel" and version " >= 5.15 < 6.7"
en
Affected
Linux
Search vendor "Linux"
Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
5.14.8
Search vendor "Linux" for product "Linux Kernel" and version "5.14.8"
en
Affected