From: Guillaume Nault gnault@redhat.com
[ Upstream commit 143a8526ab5fd4f8a0c4fe2a9cb28c181dc5a95f ]
Data beyond the UDP header might not be part of the skb's linear data. Use skb_copy_bits() instead of direct access to skb->data+X, so that we read the correct bytes even on a fragmented skb.
Fixes: 4b5f67232d95 ("net: Special handling for IP & MPLS.") Signed-off-by: Guillaume Nault gnault@redhat.com Link: https://lore.kernel.org/r/7741c46545c6ef02e70c80a9b32814b22d9616b3.162826497... Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/bareudp.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-)
diff --git a/drivers/net/bareudp.c b/drivers/net/bareudp.c index edfad93e7b68..22e26458a86e 100644 --- a/drivers/net/bareudp.c +++ b/drivers/net/bareudp.c @@ -71,12 +71,18 @@ static int bareudp_udp_encap_recv(struct sock *sk, struct sk_buff *skb) family = AF_INET6;
if (bareudp->ethertype == htons(ETH_P_IP)) { - struct iphdr *iphdr; + __u8 ipversion;
- iphdr = (struct iphdr *)(skb->data + BAREUDP_BASE_HLEN); - if (iphdr->version == 4) { - proto = bareudp->ethertype; - } else if (bareudp->multi_proto_mode && (iphdr->version == 6)) { + if (skb_copy_bits(skb, BAREUDP_BASE_HLEN, &ipversion, + sizeof(ipversion))) { + bareudp->dev->stats.rx_dropped++; + goto drop; + } + ipversion >>= 4; + + if (ipversion == 4) { + proto = htons(ETH_P_IP); + } else if (ipversion == 6 && bareudp->multi_proto_mode) { proto = htons(ETH_P_IPV6); } else { bareudp->dev->stats.rx_dropped++;