CVE-2021-47225
mac80211: fix deadlock in AP/VLAN handling
Severity Score
Exploit Likelihood
Affected Versions
Public Exploits
0Exploited in Wild
-Decision
Descriptions
In the Linux kernel, the following vulnerability has been resolved:
mac80211: fix deadlock in AP/VLAN handling
Syzbot reports that when you have AP_VLAN interfaces that are up
and close the AP interface they belong to, we get a deadlock. No
surprise - since we dev_close() them with the wiphy mutex held,
which goes back into the netdev notifier in cfg80211 and tries to
acquire the wiphy mutex there.
To fix this, we need to do two things:
1) prevent changing iftype while AP_VLANs are up, we can't
easily fix this case since cfg80211 already calls us with
the wiphy mutex held, but change_interface() is relatively
rare in drivers anyway, so changing iftype isn't used much
(and userspace has to fall back to down/change/up anyway)
2) pull the dev_close() loop over VLANs out of the wiphy mutex
section in the normal stop case
En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: mac80211: corrige el punto muerto en el manejo de AP/VLAN. Syzbot informa que cuando tienes interfaces AP_VLAN activas y cierras la interfaz AP a la que pertenecen, obtenemos un punto muerto. No es de extrañar, ya que los dev_close() los usamos con el mutex wiphy retenido, lo que regresa al notificador netdev en cfg80211 e intenta adquirir el mutex wiphy allí. Para solucionar esto, debemos hacer dos cosas: 1) evitar cambiar iftype mientras las AP_VLAN estén activas, no podemos solucionar fácilmente este caso ya que cfg80211 ya nos llama con el mutex wiphy retenido, pero change_interface() es relativamente raro en los controladores de todos modos , por lo que cambiar iftype no se usa mucho (y el espacio de usuario tiene que volver a bajar/cambiar/arriba de todos modos) 2) extraiga el bucle dev_close() sobre las VLAN de la sección wiphy mutex en el caso de detención normal
CVSS Scores
SSVC
- Decision:Track
Timeline
- 2024-04-10 CVE Reserved
- 2024-05-21 CVE Published
- 2024-05-22 EPSS Updated
- 2024-08-04 CVE Updated
- ---------- Exploited in Wild
- ---------- KEV Due Date
- ---------- First Exploit
CWE
CAPEC
References (3)
| URL | Tag | Source |
|---|---|---|
| https://git.kernel.org/stable/c/a05829a7222e9d10c416dd2dbbf3929fe6646b89 | Vuln. Introduced |
| URL | Date | SRC |
|---|
| URL | Date | SRC |
|---|---|---|
| https://git.kernel.org/stable/c/8043903fcb72f545c52e3ec74d6fd82ef79ce7c5 | 2021-06-23 | |
| https://git.kernel.org/stable/c/d5befb224edbe53056c2c18999d630dafb4a08b9 | 2021-06-08 |
| URL | Date | SRC |
|---|
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" | >= 5.12 < 5.12.13 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.12 < 5.12.13" | en |
Affected
| ||||||
| Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 5.12 < 5.13 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.12 < 5.13" | en |
Affected
| ||||||