[PATCH 3.16 205/366] pppoe: check sockaddr length in pppoe_connect()

Ben Hutchings
2018-10-14T23:24:35Z

From: Guillaume Nault <g.nault@alphalink.fr>

commit a49e2f5d5fb141884452ddb428f551b123d436b5 upstream.

We must validate sockaddr_len, otherwise userspace can pass fewer data
than we expect and we end up accessing invalid data.

Fixes: 224cf5ad14c0 ("ppp: Move the PPP drivers")
Reported-by: syzbot+4f03bdf92fdf9ef5ddab@syzkaller.appspotmail.com
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/net/ppp/pppoe.c | 4 ++++
1 file changed, 4 insertions(+)

--- a/drivers/net/ppp/pppoe.c
+++ b/drivers/net/ppp/pppoe.c
@@ -615,6 +615,10 @@ static int pppoe_connect(struct socket *
lock_sock(sk);

error = -EINVAL;
+
+ if (sockaddr_len != sizeof(struct sockaddr_pppox))
+ goto end;
+
if (sp->sa_protocol != PX_PROTO_OE)
goto end;