diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 4a71d78d0c6ad9c16bca9b0ec15eced717f601e7..7164569c1ec8076a89c29e378ca769344d8122c4 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -3094,6 +3094,25 @@ struct sk_buff *skb_segment(struct sk_buff *head_skb, int pos; int dummy; + if (list_skb && !list_skb->head_frag && skb_headlen(list_skb) && + (skb_shinfo(head_skb)->gso_type & SKB_GSO_DODGY)) { + /* gso_size is untrusted, and we have a frag_list with a linear + * non head_frag head. + * + * (we assume checking the first list_skb member suffices; + * i.e if either of the list_skb members have non head_frag + * head, then the first one has too). + * + * If head_skb's headlen does not fit requested gso_size, it + * means that the frag_list members do NOT terminate on exact + * gso_size boundaries. Hence we cannot perform skb_frag_t page + * sharing. Therefore we must fallback to copying the frag_list + * skbs; we do so by disabling SG. + */ + if (mss != GSO_BY_FRAGS && mss != skb_headlen(head_skb)) + features &= ~NETIF_F_SG; + } + __skb_push(head_skb, doffset); proto = skb_network_protocol(head_skb, &dummy); if (unlikely(!proto))