In the Linux kernel, the following vulnerability has been resolved: net: add proper RCU protection to /proc/net/ptype Yin Fengwei reported an RCU stall in ptype_seq_show() and provided a patch. Real issue is that ptype_seq_next() and ptype_seq_show() violate RCU rules. ptype_seq_show() runs under rcu_read_lock(), and reads pt->dev to get device name without any barrier. At the same time, concurrent writers can remove a packet_type structure (which is correctly freed after an RCU grace period) and clear pt->dev without an RCU grace period. Define ptype_iter_state to carry a dev pointer along seq_net_private: struct ptype_iter_state { struct seq_net_private p; struct net_device *dev; // added in this patch }; We need to record the device pointer in ptype_get_idx() and ptype_seq_next() so that ptype_seq_show() is safe against concurrent pt->dev changes. We also need to add full RCU protection in ptype_seq_next(). (Missing READ_ONCE() when reading list.next values) Many thanks to Dong Chenchen for providing a repro.
En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta: net: añadir protección RCU adecuada a /proc/net/ptype Yin Fengwei informó de un bloqueo RCU en ptype_seq_show() y proporcionó un parche. El problema real es que ptype_seq_next() y ptype_seq_show() violan las reglas RCU. ptype_seq_show() se ejecuta bajo rcu_read_lock(), y lee pt->dev para obtener el nombre del dispositivo sin ninguna barrera. Al mismo tiempo, los escritores concurrentes pueden eliminar una estructura packet_type (que se libera correctamente después de un período de gracia RCU) y borrar pt->dev sin un período de gracia RCU. Definir ptype_iter_state para llevar un puntero dev junto con seq_net_private: struct ptype_iter_state { struct seq_net_private p; struct net_device *dev; // añadido en este parche }; Necesitamos registrar el puntero del dispositivo en ptype_get_idx() y ptype_seq_next() para que ptype_seq_show() esté a salvo de cambios concurrentes en pt->dev. También necesitamos añadir protección RCU completa en ptype_seq_next(). (Falta READ_ONCE() al leer los valores de list.next) Muchas gracias a Dong Chenchen por proporcionar una reproducción.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
| Attack Vector | LOCAL |
|---|---|
| Attack Complexity | LOW |
| Privileges Required | LOW |
| User Interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality Impact | NONE |
| Integrity Impact | NONE |
| Availability Impact | HIGH |
| Source | Type | Description |
|---|---|---|
| [email protected] | Primary |
en
NVD-CWE-noinfo
|
| Vendor | Product | Version | Update | Type |
|---|---|---|---|---|
| linux | linux_kernel | * | <built-in method update of dict object at 0x7d23a59865c0> | Operating System |
| linux | linux_kernel | * | <built-in method update of dict object at 0x7d23a5984f40> | Operating System |
| linux | linux_kernel | * | <built-in method update of dict object at 0x7d23a5987cc0> | Operating System |
| linux | linux_kernel | 2.6.12 | <built-in method update of dict object at 0x7d24246c0880> | Operating System |
| linux | linux_kernel | 2.6.12 | <built-in method update of dict object at 0x7d23a59848c0> | Operating System |
| linux | linux_kernel | 2.6.12 | <built-in method update of dict object at 0x7d23a59850c0> | Operating System |
| linux | linux_kernel | 2.6.12 | <built-in method update of dict object at 0x7d24246c1a80> | Operating System |
| linux | linux_kernel | 2.6.12 | <built-in method update of dict object at 0x7d24246c18c0> | Operating System |
| linux | linux_kernel | 6.19 | <built-in method update of dict object at 0x7d24246c1640> | Operating System |
| linux | linux_kernel | 6.19 | <built-in method update of dict object at 0x7d23a59859c0> | Operating System |
| linux | linux_kernel | 6.19 | <built-in method update of dict object at 0x7d23beb81200> | Operating System |
| linux | linux_kernel | 6.19 | <built-in method update of dict object at 0x7d2424504940> | Operating System |
| linux | linux_kernel | 6.19 | <built-in method update of dict object at 0x7d23a5984e80> | Operating System |
| linux | linux_kernel | 6.19 | <built-in method update of dict object at 0x7d24246c1800> | Operating System |
| linux | linux_kernel | 6.19 | <built-in method update of dict object at 0x7d23a5985280> | Operating System |
| linux | linux_kernel | 6.19 | <built-in method update of dict object at 0x7d23a5984540> | 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:2.6.12:-:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:2.6.12:rc2:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:2.6.12:rc3:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:2.6.12:rc4:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:2.6.12:rc5:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:6.19:rc1:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:6.19:rc2:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:6.19:rc3:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:6.19:rc4:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:6.19:rc5:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:6.19:rc6:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:6.19:rc7:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:6.19:rc8:*:*:*:*:*:* |