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path: root/drivers/net/pppol2tp.c
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Diffstat (limited to 'drivers/net/pppol2tp.c')
-rw-r--r--drivers/net/pppol2tp.c94
1 files changed, 82 insertions, 12 deletions
diff --git a/drivers/net/pppol2tp.c b/drivers/net/pppol2tp.c
index e98d9773158d..f1a946785c6a 100644
--- a/drivers/net/pppol2tp.c
+++ b/drivers/net/pppol2tp.c
@@ -489,6 +489,30 @@ out:
spin_unlock_bh(&session->reorder_q.lock);
}
+static inline int pppol2tp_verify_udp_checksum(struct sock *sk,
+ struct sk_buff *skb)
+{
+ struct udphdr *uh = udp_hdr(skb);
+ u16 ulen = ntohs(uh->len);
+ struct inet_sock *inet;
+ __wsum psum;
+
+ if (sk->sk_no_check || skb_csum_unnecessary(skb) || !uh->check)
+ return 0;
+
+ inet = inet_sk(sk);
+ psum = csum_tcpudp_nofold(inet->saddr, 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);
+}
+
/* Internal receive frame. Do the real work of receiving an L2TP data frame
* here. The skb is not on a list when we get here.
* Returns 0 if the packet was a data packet and was successfully passed on.
@@ -509,6 +533,9 @@ static int pppol2tp_recv_core(struct sock *sock, struct sk_buff *skb)
if (tunnel == NULL)
goto no_tunnel;
+ if (tunnel->sock && pppol2tp_verify_udp_checksum(tunnel->sock, skb))
+ goto discard_bad_csum;
+
/* UDP always verifies the packet length. */
__skb_pull(skb, sizeof(struct udphdr));
@@ -725,6 +752,14 @@ discard:
return 0;
+discard_bad_csum:
+ LIMIT_NETDEBUG("%s: UDP: bad checksum\n", tunnel->name);
+ UDP_INC_STATS_USER(&init_net, UDP_MIB_INERRORS, 0);
+ tunnel->stats.rx_errors++;
+ kfree_skb(skb);
+
+ return 0;
+
error:
/* Put UDP header back */
__skb_push(skb, sizeof(struct udphdr));
@@ -851,7 +886,7 @@ static int pppol2tp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msgh
static const unsigned char ppph[2] = { 0xff, 0x03 };
struct sock *sk = sock->sk;
struct inet_sock *inet;
- __wsum csum = 0;
+ __wsum csum;
struct sk_buff *skb;
int error;
int hdr_len;
@@ -859,6 +894,8 @@ static int pppol2tp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msgh
struct pppol2tp_tunnel *tunnel;
struct udphdr *uh;
unsigned int len;
+ struct sock *sk_tun;
+ u16 udp_len;
error = -ENOTCONN;
if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
@@ -870,7 +907,8 @@ static int pppol2tp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msgh
if (session == NULL)
goto error;
- tunnel = pppol2tp_sock_to_tunnel(session->tunnel_sock);
+ sk_tun = session->tunnel_sock;
+ tunnel = pppol2tp_sock_to_tunnel(sk_tun);
if (tunnel == NULL)
goto error_put_sess;
@@ -893,11 +931,12 @@ static int pppol2tp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msgh
skb_reset_transport_header(skb);
/* Build UDP header */
- inet = inet_sk(session->tunnel_sock);
+ inet = inet_sk(sk_tun);
+ udp_len = hdr_len + sizeof(ppph) + total_len;
uh = (struct udphdr *) skb->data;
uh->source = inet->sport;
uh->dest = inet->dport;
- uh->len = htons(hdr_len + sizeof(ppph) + total_len);
+ uh->len = htons(udp_len);
uh->check = 0;
skb_put(skb, sizeof(struct udphdr));
@@ -919,8 +958,22 @@ static int pppol2tp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msgh
skb_put(skb, total_len);
/* Calculate UDP checksum if configured to do so */
- if (session->tunnel_sock->sk_no_check != UDP_CSUM_NOXMIT)
- csum = udp_csum_outgoing(sk, skb);
+ if (sk_tun->sk_no_check == UDP_CSUM_NOXMIT)
+ skb->ip_summed = CHECKSUM_NONE;
+ else if (!(skb->dst->dev->features & NETIF_F_V4_CSUM)) {
+ skb->ip_summed = CHECKSUM_COMPLETE;
+ csum = skb_checksum(skb, 0, udp_len, 0);
+ uh->check = csum_tcpudp_magic(inet->saddr, inet->daddr,
+ udp_len, IPPROTO_UDP, csum);
+ if (uh->check == 0)
+ uh->check = CSUM_MANGLED_0;
+ } else {
+ skb->ip_summed = CHECKSUM_PARTIAL;
+ skb->csum_start = skb_transport_header(skb) - skb->head;
+ skb->csum_offset = offsetof(struct udphdr, check);
+ uh->check = ~csum_tcpudp_magic(inet->saddr, inet->daddr,
+ udp_len, IPPROTO_UDP, 0);
+ }
/* Debug */
if (session->send_seq)
@@ -1008,13 +1061,14 @@ static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
struct sock *sk = (struct sock *) chan->private;
struct sock *sk_tun;
int hdr_len;
+ u16 udp_len;
struct pppol2tp_session *session;
struct pppol2tp_tunnel *tunnel;
int rc;
int headroom;
int data_len = skb->len;
struct inet_sock *inet;
- __wsum csum = 0;
+ __wsum csum;
struct udphdr *uh;
unsigned int len;
int old_headroom;
@@ -1060,6 +1114,8 @@ static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
/* Setup L2TP header */
pppol2tp_build_l2tp_header(session, __skb_push(skb, hdr_len));
+ udp_len = sizeof(struct udphdr) + hdr_len + sizeof(ppph) + data_len;
+
/* Setup UDP header */
inet = inet_sk(sk_tun);
__skb_push(skb, sizeof(*uh));
@@ -1067,13 +1123,9 @@ static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
uh = udp_hdr(skb);
uh->source = inet->sport;
uh->dest = inet->dport;
- uh->len = htons(sizeof(struct udphdr) + hdr_len + sizeof(ppph) + data_len);
+ uh->len = htons(udp_len);
uh->check = 0;
- /* *BROKEN* Calculate UDP checksum if configured to do so */
- if (sk_tun->sk_no_check != UDP_CSUM_NOXMIT)
- csum = udp_csum_outgoing(sk_tun, skb);
-
/* Debug */
if (session->send_seq)
PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
@@ -1108,6 +1160,24 @@ static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
skb->dst = dst_clone(__sk_dst_get(sk_tun));
pppol2tp_skb_set_owner_w(skb, sk_tun);
+ /* Calculate UDP checksum if configured to do so */
+ if (sk_tun->sk_no_check == UDP_CSUM_NOXMIT)
+ skb->ip_summed = CHECKSUM_NONE;
+ else if (!(skb->dst->dev->features & NETIF_F_V4_CSUM)) {
+ skb->ip_summed = CHECKSUM_COMPLETE;
+ csum = skb_checksum(skb, 0, udp_len, 0);
+ uh->check = csum_tcpudp_magic(inet->saddr, inet->daddr,
+ udp_len, IPPROTO_UDP, csum);
+ if (uh->check == 0)
+ uh->check = CSUM_MANGLED_0;
+ } else {
+ skb->ip_summed = CHECKSUM_PARTIAL;
+ skb->csum_start = skb_transport_header(skb) - skb->head;
+ skb->csum_offset = offsetof(struct udphdr, check);
+ uh->check = ~csum_tcpudp_magic(inet->saddr, inet->daddr,
+ udp_len, IPPROTO_UDP, 0);
+ }
+
/* Queue the packet to IP for output */
len = skb->len;
rc = ip_queue_xmit(skb, 1);
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.