CVE-2025-40337

In the Linux kernel, the following vulnerability has been resolved:

net: stmmac: Correctly handle Rx checksum offload errors

The stmmacrx function would previously set skb->ipsummed to CHECKSUM_UNNECESSARY if hardware checksum offload (CoE) was enabled and the packet was of a known IP ethertype.

However, this logic failed to check if the hardware had actually reported a checksum error. The hardware status, indicating a header or payload checksum failure, was being ignored at this stage. This could cause corrupt packets to be passed up the network stack as valid.

This patch corrects the logic by checking the csum_none status flag, which is set when the hardware reports a checksum error. If this flag is set, skb->ipsummed is now correctly set to CHECKSUMNONE, ensuring the kernel's network stack will perform its own validation and properly handle the corrupt packet.