cortina RxOverrun Panic

Vulnerability analysis

The Cortina Gemini ethernet driver detects RX overrun interrupts from one status register but attempts to clear them using an incorrect bit from a different register context. For the first port this accidentally clears the second port's overrun status, and for the second port the bit shift produces no valid bit at all, so the interrupt is never acknowledged. The interrupt then fires repeatedly in a tight loop, monopolizing the CPU and hanging the system. The fix changes the acknowledgment to use the same per-port RX overrun bit that was originally detected, properly clearing the interrupt. The vulnerability is triggered by network traffic that causes an RX overrun — an attacker on the network can flood the interface with packets to induce this condition. No special privileges are required, but the device must use the specific Cortina Gemini ethernet hardware.