In the Linux kernel, the following vulnerability has been resolved: clocksource: Use migrate_disable() to avoid calling get_random_u32() in atomic context The following bug report happened with a PREEMPT_RT kernel: BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 2012, name: kwatchdog preempt_count: 1, expected: 0 RCU nest depth: 0, expected: 0 get_random_u32+0x4f/0x110 clocksource_verify_choose_cpus+0xab/0x1a0 clocksource_verify_percpu.part.0+0x6b/0x330 clocksource_watchdog_kthread+0x193/0x1a0 It is due to the fact that clocksource_verify_choose_cpus() is invoked with preemption disabled. This function invokes get_random_u32() to obtain random numbers for choosing CPUs. The batched_entropy_32 local lock and/or the base_crng.lock spinlock in driver/char/random.c will be acquired during the call. In PREEMPT_RT kernel, they are both sleeping locks and so cannot be acquired in atomic context. Fix this problem by using migrate_disable() to allow smp_processor_id() to be reliably used without introducing atomic context. preempt_disable() is then called after clocksource_verify_choose_cpus() but before the clocksource measurement is being run to avoid introducing unexpected latency.
En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: clocksource: Use migrants_disable() para evitar llamar a get_random_u32() en un contexto atómico El siguiente informe de error ocurrió con un kernel PREEMPT_RT: ERROR: función inactiva llamada desde un contexto no válido en kernel/locking/spinlock_rt.c:48 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 2012, name: kwatchdog preempt_count: 1, expected: 0 Profundidad de anidamiento de RCU: 0, expected: 0 get_random_u32+0x4f/0x110 clocksource_verify_choose_cpus+0xab/0x1a0 clocksource_verify_percpu.part.0+0x6b/0x330 clocksource_watchdog_kthread+0x193/0x1a0 Esto se debe al hecho de que clocksource_verify_choose_cpus() se invoca con la preempción deshabilitada. Esta función invoca get_random_u32() para obtener números aleatorios para elegir las CPU. El bloqueo local batched_entropy_32 y/o el spinlock base_crng.lock en driver/char/random.c se adquirirán durante la llamada. En el kernel PREEMPT_RT, ambos son bloqueos inactivos y, por lo tanto, no se pueden adquirir en un contexto atómico. Solucione este problema utilizando migrants_disable() para permitir que smp_processor_id() se utilice de manera confiable sin introducir un contexto atómico. Luego, se llama a preempt_disable() después de clocksource_verify_choose_cpus() pero antes de que se ejecute la medición de la fuente de reloj para evitar introducir una latencia inesperada.
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
CWE-667
|
| Vendor | Product | Version | Update | Type |
|---|---|---|---|---|
| linux | linux_kernel | * | <built-in method update of dict object at 0x702bcab469c0> | Operating System |
| linux | linux_kernel | * | <built-in method update of dict object at 0x702bde4f3b80> | Operating System |
| linux | linux_kernel | * | <built-in method update of dict object at 0x702ba6c531c0> | Operating System |
| linux | linux_kernel | * | <built-in method update of dict object at 0x702bcab44840> | Operating System |
| linux | linux_kernel | * | <built-in method update of dict object at 0x702bcab44640> | Operating System |
| linux | linux_kernel | * | <built-in method update of dict object at 0x702bcab44180> | Operating System |
| linux | linux_kernel | * | <built-in method update of dict object at 0x702bde4f2f00> | Operating System |
| linux | linux_kernel | 6.14 | <built-in method update of dict object at 0x702bcab461c0> | 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:6.14:rc1:*:*:*:*:*:* |