CVE-2022-50486

A type confusion flaw was found in the Linux kernel's Texas Instruments NETCP Ethernet driver in the packet transmit function signature. A local user can trigger this issue on systems with kernel Control Flow Integrity enabled, where the incorrect return type of the ndo_start_xmit function causes CFI validation failures during indirect function calls. This results in either a kernel panic or thread termination, leading to denial of service.

The netcp_ndo_start_xmit function is declared with a return type of 'int' instead of the expected 'netdev_tx_t' enum. When CONFIG_CFI_CLANG is enabled, the kernel validates indirect function call targets against their expected prototypes to prevent control-flow hijacking attacks. The type mismatch causes CFI to reject the call, triggering either a kernel panic or killing the calling thread. This only affects systems compiled with Clang's CFI support enabled and running on Texas Instruments NETCP hardware. Without CFI enabled, the incorrect return type is harmless due to ABI compatibility between int and the enum.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

To mitigate this issue, prevent the netcp_core module from being loaded. See https://access.redhat.com/solutions/41278 for instructions on blacklisting kernel modules.