[ 15/17] l2tp: Fix PPP header erasure and memory leak

From: Greg Kroah-Hartman
Date: Tue Jun 25 2013 - 14:41:39 EST


3.0-stable review patch. If anyone has any objections, please let me know.

------------------

From: Guillaume Nault <g.nault@xxxxxxxxxxxx>

[ Upstream commit 55b92b7a11690bc377b5d373872a6b650ae88e64 ]

Copy user data after PPP framing header. This prevents erasure of the
added PPP header and avoids leaking two bytes of uninitialised memory
at the end of skb's data buffer.

Signed-off-by: Guillaume Nault <g.nault@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/l2tp/l2tp_ppp.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -350,12 +350,12 @@ static int pppol2tp_sendmsg(struct kiocb
skb_put(skb, 2);

/* Copy user data into skb */
- error = memcpy_fromiovec(skb->data, m->msg_iov, total_len);
+ error = memcpy_fromiovec(skb_put(skb, total_len), m->msg_iov,
+ total_len);
if (error < 0) {
kfree_skb(skb);
goto error_put_sess_tun;
}
- skb_put(skb, total_len);

l2tp_xmit_skb(session, skb, session->hdr_len);



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