[PATCH 3.10 14/45] pptp: fix stack info leak in pptp_getname()

From: Greg Kroah-Hartman
Date: Fri Dec 05 2014 - 18:18:42 EST

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


From: Mathias Krause <minipli@xxxxxxxxxxxxxx>

[ Upstream commit a5f6fc28d6e6cc379c6839f21820e62262419584 ]

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@xxxxxxx>
Signed-off-by: Mathias Krause <minipli@xxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
drivers/net/ppp/pptp.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/net/ppp/pptp.c
+++ b/drivers/net/ppp/pptp.c
@@ -506,7 +506,9 @@ static int pptp_getname(struct socket *s
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;

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