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: fd558d186d ("l2tp: Split pppol2tp patch into separate l2tp and ppp parts")
Reported-by: syzbot+a70ac890b23b1bf29f5c@syzkaller.appspotmail.com
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Guillaume Nault 2018-04-23 16:15:14 +02:00 committed by David S. Miller
parent b6a930fa88
commit eb1c28c058

View File

@ -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;