Linux vulnerability

What happened

In the Linux kernel, the following vulnerability has been resolved: xen/netfront: drop RX packets with a short Ethernet header handle_incoming_queue() pulls pull_to bytes into the head before calling eth_type_trans(). pull_to is the length of the first RX slot, capped at RX_COPY_THRESHOLD, and that length comes from the backend. Nothing checks it against ETH_HLEN. If the first slot is shorter than ETH_HLEN and more slots follow, the head ends up shorter than an Ethernet header while skb->len is longer, and eth_type_trans() BUG()s in __skb_pull(). If the whole packet is shorter than ETH_HLEN, eth_type_trans() reads the header past the end of the data instead. Pull at least ETH_HLEN, and drop the packet if that fails, which also drops packets too short to hold an Ethernet header. This also checks the return value of the pull, which was ignored.

Affected versions

Linux: 0d160211965b79de989cf2d170985abeb8da5ec6 through before 72d2f54367895d6e236b9857892e2e6b6036e067 (git); 0d160211965b79de989cf2d170985abeb8da5ec6 through before e2b721bc30f40ffa7ccc36a56d4e8990b8c0538e (git); 0d160211965b79de989cf2d170985abeb8da5ec6 through before 089e58805c452e52179482b1025a8e309a57f801 (git); 2.6.23 Fixed: See vendor advisory.

Why it matters

Review the vendor advisory and exposure of the affected product to determine operational impact.

Detection & mitigation

• Apply vendor-provided updates or mitigations.
• Review affected product exposure and access logs.