CVE-2024-43893

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

serial: core: check uartclk for zero to avoid divide by zero

Calling ioctl TIOCSSERIAL with an invalid baud_base can

result in uartclk being zero, which will result in a

divide by zero error in uart_get_divisor(). The check for

uartclk being zero in uart_set_info() needs to be done

before other settings are made as subsequent calls to

ioctl TIOCSSERIAL for the same port would be impacted if

the uartclk check was done where uartclk gets set.

Oops: divide error: 0000 PREEMPT SMP KASAN PTI

RIP: 0010:uart_get_divisor (drivers/tty/serial/serial_core.c:580)

Call Trace:

<TASK>

serial8250_get_divisor (drivers/tty/serial/8250/8250_port.c:2576

drivers/tty/serial/8250/8250_port.c:2589)

serial8250_do_set_termios (drivers/tty/serial/8250/8250_port.c:502

drivers/tty/serial/8250/8250_port.c:2741)

serial8250_set_termios (drivers/tty/serial/8250/8250_port.c:2862)

uart_change_line_settings (./include/linux/spinlock.h:376

./include/linux/serial_core.h:608 drivers/tty/serial/serial_core.c:222)

uart_port_startup (drivers/tty/serial/serial_core.c:342)

uart_startup (drivers/tty/serial/serial_core.c:368)

uart_set_info (drivers/tty/serial/serial_core.c:1034)

uart_set_info_user (drivers/tty/serial/serial_core.c:1059)

tty_set_serial (drivers/tty/tty_io.c:2637)

tty_ioctl (drivers/tty/tty_io.c:2647 drivers/tty/tty_io.c:2791)

__x64_sys_ioctl (fs/ioctl.c:52 fs/ioctl.c:907

fs/ioctl.c:893 fs/ioctl.c:893)

do_syscall_64 (arch/x86/entry/common.c:52

(discriminator 1) arch/x86/entry/common.c:83 (discriminator 1))

entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)

Rule: add