diff options
| author | Eric Dumazet <edumazet@google.com> | 2018-01-18 19:59:19 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-01-22 16:00:05 -0500 |
| commit | 7c68d1a6b4db9012790af7ac0f0fdc0d2083422a (patch) | |
| tree | 080fa20981e54ee032dc59e2e80a925f9d7c4dd7 /net/core | |
| parent | 18b0affaf40cf5f320258d28f7069dfff76da184 (diff) | |
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@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Cc: Jason Wang <jasowang@redhat.com>
Reported-by: syzbot+9da69ebac7dddd804552@syzkaller.appspotmail.com
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/dev.c | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index 0e0ba36eeac9..613fb4066be7 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -3151,10 +3151,21 @@ static void qdisc_pkt_len_init(struct sk_buff *skb) hdr_len = skb_transport_header(skb) - skb_mac_header(skb); /* + transport layer */ - if (likely(shinfo->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))) - hdr_len += tcp_hdrlen(skb); - else - hdr_len += sizeof(struct udphdr); + if (likely(shinfo->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))) { + const struct tcphdr *th; + struct tcphdr _tcphdr; + + th = skb_header_pointer(skb, skb_transport_offset(skb), + sizeof(_tcphdr), &_tcphdr); + if (likely(th)) + hdr_len += __tcp_hdrlen(th); + } else { + struct udphdr _udphdr; + + if (skb_header_pointer(skb, skb_transport_offset(skb), + sizeof(_udphdr), &_udphdr)) + hdr_len += sizeof(struct udphdr); + } if (shinfo->gso_type & SKB_GSO_DODGY) gso_segs = DIV_ROUND_UP(skb->len - hdr_len, |