阿里云漏洞库

In the Linux kernel, the following vulnerability has been resolved:

serial: core: Clearing the circular buffer before NULLifying it

The circular buffer is NULLified in uart_tty_port_shutdown()

under the spin lock. However, the PM or other timer based callbacks

may still trigger after this event without knowning that buffer pointer

is not valid. Since the serial code is a bit inconsistent in checking

the buffer state (some rely on the head-tail positions, some on the

buffer pointer), it's better to have both aligned, i.e. buffer pointer

to be NULL and head-tail possitions to be the same, meaning it's empty.

This will prevent asynchronous calls to dereference NULL pointer as

reported recently in 8250 case:

BUG: kernel NULL pointer dereference, address: 00000cf5

Workqueue: pm pm_runtime_work

EIP: serial8250_tx_chars (drivers/tty/serial/8250/8250_port.c:1809)

...

? serial8250_tx_chars (drivers/tty/serial/8250/8250_port.c:1809)

__start_tx (drivers/tty/serial/8250/8250_port.c:1551)

serial8250_start_tx (drivers/tty/serial/8250/8250_port.c:1654)

serial_port_runtime_suspend (include/linux/serial_core.h:667 drivers/tty/serial/serial_port.c:63)

__rpm_callback (drivers/base/power/runtime.c:393)

? serial_port_remove (drivers/tty/serial/serial_port.c:50)

rpm_suspend (drivers/base/power/runtime.c:447)

The proposed change will prevent ->start_tx() to be called during

suspend on shut down port.

建议您更新当前系统或软件至最新版，完成漏洞的修复。

参考链接
https://git.kernel.org/stable/c/7ae7104d54342433a3a73975f6569beefdd86350
https://git.kernel.org/stable/c/9cf7ea2eeb745213dc2a04103e426b960e807940
https://git.kernel.org/stable/c/bb1118905e875c111d7ccef9aee86ac5e4e7f985

CWE-ID	漏洞类型