net: qdisc_pkt_len_init() should be more robust
Without proper validation of DODGY packets, we might very well
feed qdisc_pkt_len_init() with invalid GSO packets.
tcp_hdrlen() might access out-of-bound data, so let's use
skb_header_pointer() and proper checks.
Whole story is described in commit d0c081b49137 ("flow_dissector:
properly cap thoff field")
We have the goal of validating DODGY packets earlier in the stack,
so we might very well revert this fix in the future.
Signed-off-by: Eric Dumazet <edumazet at google.com>
Cc: Willem de Bruijn <willemb at google.com>
Cc: Jason Wang <jasowang at redhat.com>
Reported-by: syzbot+9da69ebac7dddd804552 at syzkaller.appspotmail.com
Acked-by: Jason Wang <jasowang at redhat.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
UnifiedSplitRaw
