From: Eric Dumazet <edumazet@google.com> stable inclusion from stable-v4.19.131 commit 6c83456601e65a6dd371ddf595510183d198e9b1 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I6S5DO CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... --------------------------- commit 7c6d2ecbda83150b2036a2b36b21381ad4667762 upstream. Recent change in virtio_net_hdr_to_skb() broke some packetdrill tests. When --mss=XXX option is set, packetdrill always provide gso_type & gso_size for its inbound packets, regardless of packet size. if (packet->tcp && packet->mss) { if (packet->ipv4) gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4; else gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6; gso.gso_size = packet->mss; } Since many other programs could do the same, relax virtio_net_hdr_to_skb() to no longer return an error, but instead ignore gso settings. This keeps Willem intent to make sure no malicious packet could reach gso stack. Note that TCP stack has a special logic in tcp_set_skb_tso_segs() to clear gso_size for small packets. Fixes: 6dd912f82680 ("net: check untrusted gso_size at kernel entry") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Willem de Bruijn <willemb@google.com> Acked-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Cc: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Liu Jian <liujian56@huawei.com> Reviewed-by: Wei Yongjun <weiyongjun1@huawei.com> Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com> --- include/linux/virtio_net.h | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h index a7c197299fc7..0b13d8693efa 100644 --- a/include/linux/virtio_net.h +++ b/include/linux/virtio_net.h @@ -118,16 +118,17 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb, if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) { u16 gso_size = __virtio16_to_cpu(little_endian, hdr->gso_size); + struct skb_shared_info *shinfo = skb_shinfo(skb); - if (skb->len - p_off <= gso_size) - return -EINVAL; - - skb_shinfo(skb)->gso_size = gso_size; - skb_shinfo(skb)->gso_type = gso_type; + /* Too small packets are not really GSO ones. */ + if (skb->len - p_off > gso_size) { + shinfo->gso_size = gso_size; + shinfo->gso_type = gso_type; - /* Header must be checked, and gso_segs computed. */ - skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; - skb_shinfo(skb)->gso_segs = 0; + /* Header must be checked, and gso_segs computed. */ + shinfo->gso_type |= SKB_GSO_DODGY; + shinfo->gso_segs = 0; + } } return 0; -- 2.25.1