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authorSimon Arlott <simon@fire.lp0.eu>2010-05-03 10:19:33 +0000
committerDavid S. Miller <davem@davemloft.net>2010-05-03 13:27:00 -0700
commitea8420e9f5dff7324607671f0b7ab7fbf726339d (patch)
treedc7b905fd3a5b76f00705cd76d25e12cced842f5
parent1183f3838c588545592c042c0ce15015661ce7f2 (diff)
ppp_generic: pull 2 bytes so that PPP_PROTO(skb) is valid
In ppp_input(), PPP_PROTO(skb) may refer to invalid data in the skb. If this happens and (proto >= 0xc000 || proto == PPP_CCPFRAG) then the packet is passed directly to pppd. This occurs frequently when using PPPoE with an interface MTU greater than 1500 because the skb is more likely to be non-linear. The next 2 bytes need to be pulled in ppp_input(). The pull of 2 bytes in ppp_receive_frame() has been removed as it is no longer required. Signed-off-by: Simon Arlott <simon@fire.lp0.eu> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/net/ppp_generic.c29
1 files changed, 18 insertions, 11 deletions
diff --git a/drivers/net/ppp_generic.c b/drivers/net/ppp_generic.c
index 6e281bc825e..75e8903c375 100644
--- a/drivers/net/ppp_generic.c
+++ b/drivers/net/ppp_generic.c
@@ -1567,13 +1567,22 @@ ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
struct channel *pch = chan->ppp;
int proto;
- if (!pch || skb->len == 0) {
+ if (!pch) {
kfree_skb(skb);
return;
}
- proto = PPP_PROTO(skb);
read_lock_bh(&pch->upl);
+ if (!pskb_may_pull(skb, 2)) {
+ kfree_skb(skb);
+ if (pch->ppp) {
+ ++pch->ppp->dev->stats.rx_length_errors;
+ ppp_receive_error(pch->ppp);
+ }
+ goto done;
+ }
+
+ proto = PPP_PROTO(skb);
if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
/* put it on the channel queue */
skb_queue_tail(&pch->file.rq, skb);
@@ -1585,6 +1594,8 @@ ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
} else {
ppp_do_recv(pch->ppp, skb, pch);
}
+
+done:
read_unlock_bh(&pch->upl);
}
@@ -1617,7 +1628,8 @@ ppp_input_error(struct ppp_channel *chan, int code)
static void
ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
{
- if (pskb_may_pull(skb, 2)) {
+ /* note: a 0-length skb is used as an error indication */
+ if (skb->len > 0) {
#ifdef CONFIG_PPP_MULTILINK
/* XXX do channel-level decompression here */
if (PPP_PROTO(skb) == PPP_MP)
@@ -1625,15 +1637,10 @@ ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
else
#endif /* CONFIG_PPP_MULTILINK */
ppp_receive_nonmp_frame(ppp, skb);
- return;
+ } else {
+ kfree_skb(skb);
+ ppp_receive_error(ppp);
}
-
- if (skb->len > 0)
- /* note: a 0-length skb is used as an error indication */
- ++ppp->dev->stats.rx_length_errors;
-
- kfree_skb(skb);
- ppp_receive_error(ppp);
}
static void