In the Linux kernel, the following vulnerability has been resolved:
vmxnet3: fix BUG_ON in vmxnet3_get_hdr_len() for Geneve packets
vmxnet3_get_hdr_len() assumes gdesc->rcd.v4/v6/tcp always describe the
outer header, but for a Geneve-encapsulated packet the device can set
them based on the inner header instead, signalled by the
VMXNET3_RCD_HDR_INNER_SHIFT bit in the completion descriptor. Since the
function never skips the outer encapsulation, this mismatch triggers:
– BUG_ON(hdr.ipv4->protocol != IPPROTO_TCP), because the outer
protocol is UDP (Geneve), not TCP.
– BUG_ON(hdr.eth->h_proto != …), when the tunnel’s outer and inner
IP versions differ (e.g. outer IPv6/inner IPv4 or vice versa).
Check VMXNET3_RCD_HDR_INNER_SHIFT up front and bail out, since the
function cannot locate the inner header it would need to parse. Also
convert the remaining BUG_ON()s in this function to return 0
defensively.
