In the Linux kernel, the following vulnerability has been resolved: net/sched: Only allow act_ct to bind to clsact/ingress qdiscs and shared blocks As Paolo said earlier [1]: "Since the blamed commit below, classify can return TC_ACT_CONSUMED while the current skb being held by the defragmentation engine. As reported by GangMin Kim, if such packet is that may cause a UaF when the defrag engine later on tries to tuch again such packet." act_ct was never meant to be used in the egress path, however some users are attaching it to egress today [2]. Attempting to reach a middle ground, we noticed that, while most qdiscs are not handling TC_ACT_CONSUMED, clsact/ingress qdiscs are. With that in mind, we address the issue by only allowing act_ct to bind to clsact/ingress qdiscs and shared blocks. That way it's still possible to attach act_ct to egress (albeit only with clsact). [1] https://lore.kernel.org/netdev/674b8cbfc385c6f37fb29a1de08d8fe5c2b0fbee.1771321118.git.pabeni@redhat.com/ [2] https://lore.kernel.org/netdev/[email protected]/
En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta: net/sched: Solo permitir que act_ct se vincule a qdiscs clsact/de entrada y bloques compartidos Como Paolo dijo anteriormente [1]: 'Desde el commit culpado a continuación, classify puede devolver TC_ACT_CONSUMED mientras el skb actual está siendo retenido por el motor de desfragmentación. Según lo informado por GangMin Kim, si dicho paquete es uno que puede causar un UaF cuando el motor de desfragmentación más tarde intente tocar de nuevo dicho paquete.' act_ct nunca estuvo destinado a ser usado en la ruta de salida, sin embargo, algunos usuarios lo están adjuntando a la salida hoy [2]. Intentando llegar a un punto intermedio, notamos que, mientras que la mayoría de los qdiscs no están manejando TC_ACT_CONSUMED, los qdiscs clsact/de entrada sí lo están. Con eso en mente, abordamos el problema permitiendo solo que act_ct se vincule a qdiscs clsact/de entrada y bloques compartidos. De esa manera, todavía es posible adjuntar act_ct a la salida (aunque solo con clsact). [1] https://lore.kernel.org/netdev/674b8cbfc385c6f37fb29a1de08d8fe5c2b0fbee.1771321118.git.pabeni@redhat.com/ [2] https://lore.kernel.org/netdev/[email protected]/
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
| Attack Vector | LOCAL |
|---|---|
| Attack Complexity | LOW |
| Privileges Required | LOW |
| User Interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality Impact | HIGH |
| Integrity Impact | HIGH |
| Availability Impact | HIGH |
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Type: Secondary
Exploitability Score: 1.8
Impact Score: 5.9
| Source | Type | Description |
|---|---|---|
| [email protected] | Primary |
en
CWE-416
|
| Vendor | Product | Version | Update | Type |
|---|---|---|---|---|
| linux | linux_kernel | * | <built-in method update of dict object at 0x702bdc9f5480> | Operating System |
| linux | linux_kernel | * | <built-in method update of dict object at 0x702bdc9f4b80> | Operating System |
| linux | linux_kernel | * | <built-in method update of dict object at 0x702bdc9f67c0> | Operating System |
| linux | linux_kernel | * | <built-in method update of dict object at 0x702bdc5e83c0> | Operating System |
| linux | linux_kernel | * | <built-in method update of dict object at 0x702bdc9f7fc0> | Operating System |
| linux | linux_kernel | * | <built-in method update of dict object at 0x702bdc9f5f80> | Operating System |
| linux | linux_kernel | * | <built-in method update of dict object at 0x702b5025e3c0> | Operating System |
| linux | linux_kernel | 7.0 | <built-in method update of dict object at 0x702bdc9f4fc0> | Operating System |
| linux | linux_kernel | 7.0 | <built-in method update of dict object at 0x702bdc9f6740> | Operating System |
| Vulnerable | CPE |
|---|---|
| Yes | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:* |