path: root/net
diff options
authorGuillaume Nault <g.nault@alphalink.fr>2018-06-13 15:09:20 +0200
committerDavid S. Miller <davem@davemloft.net>2018-06-14 17:10:19 -0700
commit3e1bc8bf974e2d4e7beb842a4c801c2542eff3bd (patch)
tree5de6f40851edb8e21f64c182698b3b928db1b8c5 /net
parent7ac6ab1f8a38ba7f8d97f95475bb6a2575db4658 (diff)
l2tp: prevent pppol2tp_connect() from creating kernel sockets
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>
Diffstat (limited to 'net')
1 files changed, 9 insertions, 0 deletions
diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c
index 8b3b6947a07d..1b24f76ae210 100644
--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -701,6 +701,15 @@ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
.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;

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