At this point, skb->data points to skb_transport_header. So, headroom check is wrong. For some case:bridge(UFO is on) + eth device(UFO is off), there is no enough headroom for IPv6 frag head. But headroom check is always false. This will bring about data be moved to there prior to skb->head, when adding IPv6 frag header to skb.
Unified · Split
| @@ -1335,7 +1335,7 @@ static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb, u32 features) · 1334 unmodified lines | ||
| 1335 | 1335 | skb->ip_summed = CHECKSUM_NONE; |
| 1336 | 1336 | |
| 1337 | 1337 | /* Check if there is enough headroom to insert fragment header. */ |
| 1338 | − if ((skb_headroom(skb) < frag_hdr_sz) && | |
| 1338 | + if ((skb_mac_header(skb) < skb->head + frag_hdr_sz) && | |
| 1339 | 1339 | pskb_expand_head(skb, frag_hdr_sz, 0, GFP_ATOMIC)) |
| 1340 | 1340 | goto out; |
| 1341 | 1341 | |