In the Linux kernel, the following vulnerability has been resolved: net: missing check virtio Two missing check in virtio_net_hdr_to_skb() allowed syzbot to crash kernels again 1. After the skb_segment function the buffer may become non-linear (nr_frags != 0), but since the SKBTX_SHARED_FRAG flag is not set anywhere the __skb_linearize function will not be executed, then the buffer will remain non-linear. Then the condition (offset >= skb_headlen(skb)) becomes true, which causes WARN_ON_ONCE in skb_checksum_help. 2. The struct sk_buff and struct virtio_net_hdr members must be mathematically related. (gso_size) must be greater than (needed) otherwise WARN_ON_ONCE. (remainder) must be greater than (needed) otherwise WARN_ON_ONCE. (remainder) may be 0 if division is without remainder. offset+2 (4191) > skb_headlen() (1116) WARNING: CPU: 1 PID: 5084 at net/core/dev.c:3303 skb_checksum_help+0x5e2/0x740 net/core/dev.c:3303 Modules linked in: CPU: 1 PID: 5084 Comm: syz-executor336 Not t…