Vulnerability CVE-2024-43893
Published: 2024-08-26

Description:
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

 References:
https://git.kernel.org/stable/c/3bbd90fca824e6fd61fb20f6dd2b0fa5f8b14bba
https://git.kernel.org/stable/c/55b2a5d331a6ceb1c4372945fdb77181265ba24f
https://git.kernel.org/stable/c/52b138f1021113e593ee6ad258ce08fe90693a9e
https://git.kernel.org/stable/c/9196e42a3b8eeff1707e6ef769112b4b6096be49
https://git.kernel.org/stable/c/e13ba3fe5ee070f8a9dab60029d52b1f61da5051
https://git.kernel.org/stable/c/e3ad503876283ac3fcca922a1bf243ef9eb0b0e2
https://git.kernel.org/stable/c/68dc02f319b9ee54dc23caba742a5c754d1cccc8
https://git.kernel.org/stable/c/6eabce6608d6f3440f4c03aa3d3ef50a47a3d193
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