diff options
| author | Simon Arlott | 2010-05-03 10:19:33 +0000 |
|---|---|---|
| committer | David S. Miller | 2010-05-03 13:27:00 -0700 |
| commit | ea8420e9f5dff7324607671f0b7ab7fbf726339d (patch) | |
| tree | dc7b905fd3a5b76f00705cd76d25e12cced842f5 | |
| parent | 1183f3838c588545592c042c0ce15015661ce7f2 (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.c | 29 |
1 files changed, 18 insertions, 11 deletions
diff --git a/drivers/net/ppp_generic.c b/drivers/net/ppp_generic.c index 6e281bc825e5..75e8903c3754 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 |