Bug 2307866 (CVE-2024-43893)
| Summary: | CVE-2024-43893 kernel: serial: core: check uartclk for zero to avoid divide by zero | ||
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| Product: | [Other] Security Response | Reporter: | OSIDB Bzimport <bzimport> |
| Component: | vulnerability | Assignee: | Product Security DevOps Team <prodsec-dev> |
| Status: | NEW --- | QA Contact: | |
| Severity: | low | Docs Contact: | |
| Priority: | low | ||
| Version: | unspecified | CC: | dfreiber, drow, jburrell, vkumar |
| Target Milestone: | --- | Keywords: | Security |
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | If docs needed, set a value | |
| Doc Text: |
A divide by zero vulnerability was found in the uart_get_divisor() function in the Linux Kernel's serial core subsystem. This issue is caused by the improper handling of invalid baud rates. When an invalid baud_base is specified using the TIOCSSERIAL ioctl command, if uartclk is zero, a subsequent call to uart_get_divisor() results in a divide by zero error. A local attacker could exploit this vulnerability by issuing a specially crafted TIOCSSERIAL ioctl call with an invalid baud_base value. This could cause a divide by zero error, leading to a kernel crash and denial of service.
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Story Points: | --- |
| Clone Of: | Environment: | ||
| Last Closed: | Type: | --- | |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
| Bug Depends On: | 2308174 | ||
| Bug Blocks: | |||
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