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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.c44
1 files changed, 24 insertions, 20 deletions
diff --git a/drivers/net/pppol2tp.c b/drivers/net/pppol2tp.c
index ed8ead4..440e190 100644
--- a/drivers/net/pppol2tp.c
+++ b/drivers/net/pppol2tp.c
@@ -491,44 +491,46 @@ static int pppol2tp_recv_core(struct sock *sock, struct sk_buff *skb)
u16 hdrflags;
u16 tunnel_id, session_id;
int length;
- struct udphdr *uh;
+ int offset;
tunnel = pppol2tp_sock_to_tunnel(sock);
if (tunnel == NULL)
goto error;
+ /* UDP always verifies the packet length. */
+ __skb_pull(skb, sizeof(struct udphdr));
+
/* Short packet? */
- if (skb->len < sizeof(struct udphdr)) {
+ if (!pskb_may_pull(skb, 12)) {
PRINTK(tunnel->debug, PPPOL2TP_MSG_DATA, KERN_INFO,
"%s: recv short packet (len=%d)\n", tunnel->name, skb->len);
goto error;
}
/* Point to L2TP header */
- ptr = skb->data + sizeof(struct udphdr);
+ ptr = skb->data;
/* Get L2TP header flags */
hdrflags = ntohs(*(__be16*)ptr);
/* Trace packet contents, if enabled */
if (tunnel->debug & PPPOL2TP_MSG_DATA) {
+ length = min(16u, skb->len);
+ if (!pskb_may_pull(skb, length))
+ goto error;
+
printk(KERN_DEBUG "%s: recv: ", tunnel->name);
- for (length = 0; length < 16; length++)
- printk(" %02X", ptr[length]);
+ offset = 0;
+ do {
+ printk(" %02X", ptr[offset]);
+ } while (++offset < length);
+
printk("\n");
}
/* Get length of L2TP packet */
- uh = (struct udphdr *) skb_transport_header(skb);
- length = ntohs(uh->len) - sizeof(struct udphdr);
-
- /* Too short? */
- if (length < 12) {
- PRINTK(tunnel->debug, PPPOL2TP_MSG_DATA, KERN_INFO,
- "%s: recv short L2TP packet (len=%d)\n", tunnel->name, length);
- goto error;
- }
+ length = skb->len;
/* If type is control packet, it is handled by userspace. */
if (hdrflags & L2TP_HDRFLAG_T) {
@@ -606,7 +608,6 @@ static int pppol2tp_recv_core(struct sock *sock, struct sk_buff *skb)
"%s: recv data has no seq numbers when required. "
"Discarding\n", session->name);
session->stats.rx_seq_discards++;
- session->stats.rx_errors++;
goto discard;
}
@@ -625,7 +626,6 @@ static int pppol2tp_recv_core(struct sock *sock, struct sk_buff *skb)
"%s: recv data has no seq numbers when required. "
"Discarding\n", session->name);
session->stats.rx_seq_discards++;
- session->stats.rx_errors++;
goto discard;
}
@@ -634,10 +634,14 @@ static int pppol2tp_recv_core(struct sock *sock, struct sk_buff *skb)
}
/* If offset bit set, skip it. */
- if (hdrflags & L2TP_HDRFLAG_O)
- ptr += 2 + ntohs(*(__be16 *) ptr);
+ if (hdrflags & L2TP_HDRFLAG_O) {
+ offset = ntohs(*(__be16 *)ptr);
+ skb->transport_header += 2 + offset;
+ if (!pskb_may_pull(skb, skb_transport_offset(skb) + 2))
+ goto discard;
+ }
- skb_pull(skb, ptr - skb->data);
+ __skb_pull(skb, skb_transport_offset(skb));
/* Skip PPP header, if present. In testing, Microsoft L2TP clients
* don't send the PPP header (PPP header compression enabled), but
@@ -673,7 +677,6 @@ static int pppol2tp_recv_core(struct sock *sock, struct sk_buff *skb)
*/
if (PPPOL2TP_SKB_CB(skb)->ns != session->nr) {
session->stats.rx_seq_discards++;
- session->stats.rx_errors++;
PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
"%s: oos pkt %hu len %d discarded, "
"waiting for %hu, reorder_q_len=%d\n",
@@ -698,6 +701,7 @@ static int pppol2tp_recv_core(struct sock *sock, struct sk_buff *skb)
return 0;
discard:
+ session->stats.rx_errors++;
kfree_skb(skb);
sock_put(session->sock);
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