From eb1c28c05894a4b1f6b56c5bf072205e64cfa280 Mon Sep 17 00:00:00 2001 From: Guillaume Nault Date: Mon, 23 Apr 2018 16:15:14 +0200 Subject: [PATCH] l2tp: check sockaddr length in pppol2tp_connect() Check sockaddr_len before dereferencing sp->sa_protocol, to ensure that it actually points to valid data. Fixes: fd558d186df2 ("l2tp: Split pppol2tp patch into separate l2tp and ppp parts") Reported-by: syzbot+a70ac890b23b1bf29f5c@syzkaller.appspotmail.com Signed-off-by: Guillaume Nault Signed-off-by: David S. Miller --- net/l2tp/l2tp_ppp.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c index 1404bc1c1bb7..1fd9e145076a 100644 --- a/net/l2tp/l2tp_ppp.c +++ b/net/l2tp/l2tp_ppp.c @@ -619,6 +619,13 @@ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr, lock_sock(sk); error = -EINVAL; + + if (sockaddr_len != sizeof(struct sockaddr_pppol2tp) && + sockaddr_len != sizeof(struct sockaddr_pppol2tpv3) && + sockaddr_len != sizeof(struct sockaddr_pppol2tpin6) && + sockaddr_len != sizeof(struct sockaddr_pppol2tpv3in6)) + goto end; + if (sp->sa_protocol != PX_PROTO_OL2TP) goto end; -- 2.30.2