3.16.61-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Guillaume Nault g.nault@alphalink.fr
commit 3e1bc8bf974e2d4e7beb842a4c801c2542eff3bd upstream.
If 'fd' is negative, l2tp_tunnel_create() creates a tunnel socket using the configuration passed in 'tcfg'. Currently, pppol2tp_connect() sets the relevant fields to zero, tricking l2tp_tunnel_create() into setting up an unusable kernel socket.
We can't set 'tcfg' with the required fields because there's no way to get them from the current connect() parameters. So let's restrict kernel sockets creation to the netlink API, which is the original use case.
Fixes: 789a4a2c61d8 ("l2tp: Add support for static unmanaged L2TPv3 tunnels") 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 --- net/l2tp/l2tp_ppp.c | 9 +++++++++ 1 file changed, 9 insertions(+)
--- a/net/l2tp/l2tp_ppp.c +++ b/net/l2tp/l2tp_ppp.c @@ -723,6 +723,15 @@ static int pppol2tp_connect(struct socke .encap = L2TP_ENCAPTYPE_UDP, .debug = 0, }; + + /* Prevent l2tp_tunnel_register() from trying to set up + * a kernel socket. + */ + if (fd < 0) { + error = -EBADF; + goto end; + } + error = l2tp_tunnel_create(sock_net(sk), fd, ver, tunnel_id, peer_tunnel_id, &tcfg, &tunnel); if (error < 0) goto end;