Divide By Zero Affecting kernel-rt-core package, versions *

Note: Versions mentioned in the description apply only to the upstream kernel-rt-core package and not the kernel-rt-core package as distributed by Centos. See How to fix? for Centos:8 relevant fixed versions and status.

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

• https://access.redhat.com/security/cve/CVE-2024-43893
• https://git.kernel.org/stable/c/3bbd90fca824e6fd61fb20f6dd2b0fa5f8b14bba
• https://git.kernel.org/stable/c/52b138f1021113e593ee6ad258ce08fe90693a9e
• https://git.kernel.org/stable/c/55b2a5d331a6ceb1c4372945fdb77181265ba24f
• https://git.kernel.org/stable/c/68dc02f319b9ee54dc23caba742a5c754d1cccc8
• https://git.kernel.org/stable/c/6eabce6608d6f3440f4c03aa3d3ef50a47a3d193
• https://git.kernel.org/stable/c/9196e42a3b8eeff1707e6ef769112b4b6096be49
• https://git.kernel.org/stable/c/e13ba3fe5ee070f8a9dab60029d52b1f61da5051
• https://git.kernel.org/stable/c/e3ad503876283ac3fcca922a1bf243ef9eb0b0e2