Commit 19937d04 authored May 03, 2010 by Simon Arlott Committed by David S. Miller May 03, 2010

ppp_generic: handle non-linear skbs when passing them to pppd



Frequently when using PPPoE with an interface MTU greater than 1500,
the skb is likely to be non-linear. If the skb needs to be passed to
pppd then the skb data must be read correctly.

The previous commit fixes an issue with accidentally sending skbs
to pppd based on an invalid read of the protocol type. When that
error occurred pppd was reading invalid skb data too.

Signed-off-by: Simon Arlott <simon@fire.lp0.eu>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent ea8420e9

drivers/net/ppp_generic.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -405,6 +405,7 @@ static ssize_t ppp_read(struct file file, char __user buf,
		DECLARE_WAITQUEUE(wait, current);
		ssize_t ret;
		struct sk_buff *skb = NULL;
		struct iovec iov;

		ret = count;

		@@ -448,7 +449,9 @@ static ssize_t ppp_read(struct file file, char __user buf,
		if (skb->len > count)
		goto outf;
		ret = -EFAULT;
		if (copy_to_user(buf, skb->data, skb->len))
		iov.iov_base = buf;
		iov.iov_len = count;
		if (skb_copy_datagram_iovec(skb, 0, &iov, skb->len))
		goto outf;
		ret = skb->len;