In the Linux kernel, the following vulnerability has been resolved:
serial: 8250_mid: Fix NULL function pointer dereference on DNV/ICX-D/SNR platforms
Commit b1b4efea05a5 (serial: 8250_mid: Disable DMA for selected platforms) replaced the dnv_board setup and exit callbacks with PTR_IF(false, …), which evaluates to NULL. However, the three call sites in mid8250_probe() and mid8250_remove() unconditionally dereference these function pointers without NULL checks, causing a NULL pointer dereference (kernel oops) on any Denverton (DNV), Ice Lake Xeon D (ICX-D/CDF), or Snowridge (SNR) platform.
Fix this by adding the missing NULL checks before calling the setup and exit callbacks.
References
- https://git.kernel.org/stable/c/1096397c31f6bffa95e77bdd18fbca085be83e10
- https://git.kernel.org/stable/c/600dcd548fb2b00a69f447684f52ba45d5a3540e
- https://git.kernel.org/stable/c/7fb13fd7e9a59a37cd911efff83abe19e3ee029d
- https://git.kernel.org/stable/c/8cbad52ccfa6a7f089cfab34979bc6cc3bff25be
- https://git.kernel.org/stable/c/b2a3eeb57ba24f8a0e34a69d40adcc63e5b9ca56