From: Mathias Krause <minipli@googlemail.com>
Date: Wed, 19 Nov 2014 17:05:26 +0000 (+0100)
Subject: pptp: fix stack info leak in pptp_getname()
X-Git-Tag: v3.16.35~3528
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=29065ee599be064881d09bc389f66f4d3e744a12;p=thirdparty%2Fkernel%2Fstable.git

pptp: fix stack info leak in pptp_getname()

commit a5f6fc28d6e6cc379c6839f21820e62262419584 upstream.

pptp_getname() only partially initializes the stack variable sa,
particularly only fills the pptp part of the sa_addr union. The code
thereby discloses 16 bytes of kernel stack memory via getsockname().

Fix this by memset(0)'ing the union before.

Cc: Dmitry Kozlov <xeb@mail.ru>
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
---

diff --git a/drivers/net/ppp/pptp.c b/drivers/net/ppp/pptp.c
index 1aff970be33ec..1dc628ffce2b5 100644
--- a/drivers/net/ppp/pptp.c
+++ b/drivers/net/ppp/pptp.c
@@ -506,7 +506,9 @@ static int pptp_getname(struct socket *sock, struct sockaddr *uaddr,
 	int len = sizeof(struct sockaddr_pppox);
 	struct sockaddr_pppox sp;
 
-	sp.sa_family	  = AF_PPPOX;
+	memset(&sp.sa_addr, 0, sizeof(sp.sa_addr));
+
+	sp.sa_family    = AF_PPPOX;
 	sp.sa_protocol  = PX_PROTO_PPTP;
 	sp.sa_addr.pptp = pppox_sk(sock->sk)->proto.pptp.src_addr;