net pppoe: Check packet length on all receive paths
The length field in the PPPOE header wasn't checked completely.
This patch causes all packets shorter than the declared length
to be dropped.
It also changes the memcpy_toiovec call to skb_copy_datagram_iovec
so that paged packets (rare for PPPOE) are handled properly.
Thanks to Ilja of the Netric Security Team for discovering and
reporting this bug, and Chris Wright for the total_len check.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/pppoe.c b/drivers/net/pppoe.c
index 58a26a4..d89ccfd 100644
--- a/drivers/net/pppoe.c
+++ b/drivers/net/pppoe.c
@@ -341,12 +341,6 @@
struct pppox_sock *relay_po;
if (sk->sk_state & PPPOX_BOUND) {
- struct pppoe_hdr *ph = pppoe_hdr(skb);
- int len = ntohs(ph->length);
- skb_pull_rcsum(skb, sizeof(struct pppoe_hdr));
- if (pskb_trim_rcsum(skb, len))
- goto abort_kfree;
-
ppp_input(&po->chan, skb);
} else if (sk->sk_state & PPPOX_RELAY) {
relay_po = get_item_by_addr(&po->pppoe_relay);
@@ -357,7 +351,6 @@
if ((sk_pppox(relay_po)->sk_state & PPPOX_CONNECTED) == 0)
goto abort_put;
- skb_pull(skb, sizeof(struct pppoe_hdr));
if (!__pppoe_xmit(sk_pppox(relay_po), skb))
goto abort_put;
} else {
@@ -388,6 +381,7 @@
{
struct pppoe_hdr *ph;
struct pppox_sock *po;
+ int len;
if (!(skb = skb_share_check(skb, GFP_ATOMIC)))
goto out;
@@ -399,10 +393,21 @@
goto drop;
ph = pppoe_hdr(skb);
+ len = ntohs(ph->length);
+
+ skb_pull_rcsum(skb, sizeof(*ph));
+ if (skb->len < len)
+ goto drop;
po = get_item(ph->sid, eth_hdr(skb)->h_source, dev->ifindex);
- if (po != NULL)
- return sk_receive_skb(sk_pppox(po), skb, 0);
+ if (!po)
+ goto drop;
+
+ if (pskb_trim_rcsum(skb, len))
+ goto drop;
+
+ return sk_receive_skb(sk_pppox(po), skb, 0);
+
drop:
kfree_skb(skb);
out:
@@ -937,12 +942,10 @@
m->msg_namelen = 0;
if (skb) {
- struct pppoe_hdr *ph = pppoe_hdr(skb);
- const int len = ntohs(ph->length);
-
- error = memcpy_toiovec(m->msg_iov, (unsigned char *) &ph->tag[0], len);
+ total_len = min(total_len, skb->len);
+ error = skb_copy_datagram_iovec(skb, 0, m->msg_iov, total_len);
if (error == 0)
- error = len;
+ error = total_len;
}
kfree_skb(skb);