netdev - [PATCH net,stable 1/2] l2tp: Fix PPP header erasure and memory leak

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Message-ID: <20130612140723.GB3500@alphalink.fr>
Date:	Wed, 12 Jun 2013 16:07:23 +0200
From:	Guillaume Nault <g.nault@...halink.fr>
To:	netdev@...r.kernel.org
Cc:	James Chapman <jchapman@...alix.com>,
	David Miller <davem@...emloft.net>
Subject: [PATCH net,stable 1/2] l2tp: Fix PPP header erasure and memory leak

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@...halink.fr>
---
 net/l2tp/l2tp_ppp.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c
index 637a341..681c626 100644
--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -346,12 +346,12 @@ static int pppol2tp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msgh
 	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);
 
-- 
1.7.10.4


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