@@ -495,52 +495,6 @@ out:
spin_unlock_bh(&session->reorder_q.lock);
}
-static inline int l2tp_verify_udp_checksum(struct sock *sk,
- struct sk_buff *skb)
-{
- struct udphdr *uh = udp_hdr(skb);
- u16 ulen = ntohs(uh->len);
- __wsum psum;
-
- if (sk->sk_no_check || skb_csum_unnecessary(skb))
- return 0;
-
-#if IS_ENABLED(CONFIG_IPV6)
- if (sk->sk_family == PF_INET6 && !l2tp_tunnel(sk)->v4mapped) {
- if (!uh->check) {
- LIMIT_NETDEBUG(KERN_INFO "L2TP: IPv6: checksum is 0\n");
- return 1;
- }
- if ((skb->ip_summed == CHECKSUM_COMPLETE) &&
- !csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
- &ipv6_hdr(skb)->daddr, ulen,
- IPPROTO_UDP, skb->csum)) {
- skb->ip_summed = CHECKSUM_UNNECESSARY;
- return 0;
- }
- skb->csum = ~csum_unfold(csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
- &ipv6_hdr(skb)->daddr,
- skb->len, IPPROTO_UDP,
- 0));
- } else
-#endif
- {
- struct inet_sock *inet;
- if (!uh->check)
- return 0;
- inet = inet_sk(sk);
- psum = csum_tcpudp_nofold(inet->inet_saddr, inet->inet_daddr,
- ulen, IPPROTO_UDP, 0);
-
- if ((skb->ip_summed == CHECKSUM_COMPLETE) &&
- !csum_fold(csum_add(psum, skb->csum)))
- return 0;
- skb->csum = psum;
- }
-
- return __skb_checksum_complete(skb);
-}
-
static int l2tp_seq_check_rx_window(struct l2tp_session *session, u32 nr)
{
u32 nws;
@@ -895,8 +849,7 @@ static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb,
u16 version;
int length;
- if (tunnel->sock && l2tp_verify_udp_checksum(tunnel->sock, skb))
- goto discard_bad_csum;
+ /* UDP has verifed checksum */
/* UDP always verifies the packet length. */
__skb_pull(skb, sizeof(struct udphdr));
@@ -979,14 +932,6 @@ static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb,
return 0;
-discard_bad_csum:
- LIMIT_NETDEBUG("%s: UDP: bad checksum\n", tunnel->name);
- UDP_INC_STATS_USER(tunnel->l2tp_net, UDP_MIB_INERRORS, 0);
- atomic_long_inc(&tunnel->stats.rx_errors);
- kfree_skb(skb);
-
- return 0;
-
error:
/* Put UDP header back */
__skb_push(skb, sizeof(struct udphdr));
Validating the UDP checksum is now done in UDP before handing packets to the encapsulation layer. Note that this also eliminates the "feature" where L2TP can ignore a non-zero UDP checksum (doing this was contrary to RFC 1122). Signed-off-by: Tom Herbert <therbert@google.com> --- net/l2tp/l2tp_core.c | 57 +--------------------------------------------------- 1 file changed, 1 insertion(+), 56 deletions(-)