CVE-2024-44950 serial: sc16is7xx: fix invalid FIFO access with special register set
A race condition in the sc16is7xx serial driver causes invalid FIFO access, potentially leading to system instability or denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2024-44950?
CVE-2024-44950 is a high-severity vulnerability in Linux kernel, published on 4 Sep 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
serial: sc16is7xx: fix invalid FIFO access with special register set
When enabling access to the special register set, Receiver time-out and RHR interrupts can happen. In this case, the IRQ handler will try to read from the FIFO thru the RHR register at address 0x00, but address 0x00 is mapped to DLL register, resulting in erroneous FIFO reading.
Call graph example: sc16is7xx_startup(): entry sc16is7xx_ms_proc(): entry sc16is7xx_set_termios(): entry sc16is7xx_set_baud(): DLH/DLL = $009C --> access special register set sc16is7xx_port_irq() entry --> IIR is 0x0C sc16is7xx_handle_rx() entry sc16is7xx_fifo_read(): --> unable to access FIFO (RHR) because it is mapped to DLL (LCR=LCR_CONF_MODE_A) sc16is7xx_set_baud(): exit --> Restore access to general register set
Fix the problem by claiming the efr_lock mutex when accessing the Special register set.
Which versions are affected by CVE-2024-44950?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2024-44950?
Apply the vendor's patch.
Is CVE-2024-44950 being exploited?
There is no known exploitation of CVE-2024-44950 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-50204, AZL-50239, BELL-CVE-2024-44950, DEBIAN-CVE-2024-44950, GHSA-hw6f-2v4x-m477, ROOT-OS-DEBIAN-11-CVE-2024-44950 and 2 more.