summaryrefslogtreecommitdiff
path: root/net/l2tp
diff options
context:
space:
mode:
authorGuillaume Nault <g.nault@alphalink.fr>2017-09-01 17:58:51 +0200
committerDavid S. Miller <davem@davemloft.net>2017-09-03 11:04:21 -0700
commitf026bc29a8e093edfbb2a77700454b285c97e8ad (patch)
tree7dfc0aa94822a5d36f1f63f2e07fa7dae339a6c2 /net/l2tp
parentf3c66d4e144a0904ea9b95d23ed9f8eb38c11bfb (diff)
l2tp: pass tunnel pointer to ->session_create()
Using l2tp_tunnel_find() in pppol2tp_session_create() and l2tp_eth_create() is racy, because no reference is held on the returned session. These functions are only used to implement the ->session_create callback which is run by l2tp_nl_cmd_session_create(). Therefore searching for the parent tunnel isn't necessary because l2tp_nl_cmd_session_create() already has a pointer to it and holds a reference. This patch modifies ->session_create()'s prototype to directly pass the the parent tunnel as parameter, thus avoiding searching for it in pppol2tp_session_create() and l2tp_eth_create(). Since we have to touch the ->session_create() call in l2tp_nl_cmd_session_create(), let's also remove the useless conditional: we know that ->session_create isn't NULL at this point because it's already been checked earlier in this same function. Finally, one might be tempted to think that the removed l2tp_tunnel_find() calls were harmless because they would return the same tunnel as the one held by l2tp_nl_cmd_session_create() anyway. But that tunnel might be removed and a new one created with same tunnel Id before the l2tp_tunnel_find() call. In this case l2tp_tunnel_find() would return the new tunnel which wouldn't be protected by the reference held by l2tp_nl_cmd_session_create(). Fixes: 309795f4bec2 ("l2tp: Add netlink control API for L2TP") Fixes: d9e31d17ceba ("l2tp: Add L2TP ethernet pseudowire support") Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/l2tp')
-rw-r--r--net/l2tp/l2tp_core.h4
-rw-r--r--net/l2tp/l2tp_eth.c11
-rw-r--r--net/l2tp/l2tp_netlink.c8
-rw-r--r--net/l2tp/l2tp_ppp.c19
4 files changed, 17 insertions, 25 deletions
diff --git a/net/l2tp/l2tp_core.h b/net/l2tp/l2tp_core.h
index 4593d48df953..a305e0c5925a 100644
--- a/net/l2tp/l2tp_core.h
+++ b/net/l2tp/l2tp_core.h
@@ -201,7 +201,9 @@ struct l2tp_tunnel {
};
struct l2tp_nl_cmd_ops {
- int (*session_create)(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg);
+ int (*session_create)(struct net *net, struct l2tp_tunnel *tunnel,
+ u32 session_id, u32 peer_session_id,
+ struct l2tp_session_cfg *cfg);
int (*session_delete)(struct l2tp_session *session);
};
diff --git a/net/l2tp/l2tp_eth.c b/net/l2tp/l2tp_eth.c
index 4de2ec94b08c..87da9ef61860 100644
--- a/net/l2tp/l2tp_eth.c
+++ b/net/l2tp/l2tp_eth.c
@@ -262,24 +262,19 @@ static void l2tp_eth_adjust_mtu(struct l2tp_tunnel *tunnel,
dev->needed_headroom += session->hdr_len;
}
-static int l2tp_eth_create(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg)
+static int l2tp_eth_create(struct net *net, struct l2tp_tunnel *tunnel,
+ u32 session_id, u32 peer_session_id,
+ struct l2tp_session_cfg *cfg)
{
unsigned char name_assign_type;
struct net_device *dev;
char name[IFNAMSIZ];
- struct l2tp_tunnel *tunnel;
struct l2tp_session *session;
struct l2tp_eth *priv;
struct l2tp_eth_sess *spriv;
int rc;
struct l2tp_eth_net *pn;
- tunnel = l2tp_tunnel_find(net, tunnel_id);
- if (!tunnel) {
- rc = -ENODEV;
- goto out;
- }
-
if (cfg->ifname) {
strlcpy(name, cfg->ifname, IFNAMSIZ);
name_assign_type = NET_NAME_USER;
diff --git a/net/l2tp/l2tp_netlink.c b/net/l2tp/l2tp_netlink.c
index 57427d430f10..7135f4645d3a 100644
--- a/net/l2tp/l2tp_netlink.c
+++ b/net/l2tp/l2tp_netlink.c
@@ -643,10 +643,10 @@ static int l2tp_nl_cmd_session_create(struct sk_buff *skb, struct genl_info *inf
break;
}
- ret = -EPROTONOSUPPORT;
- if (l2tp_nl_cmd_ops[cfg.pw_type]->session_create)
- ret = (*l2tp_nl_cmd_ops[cfg.pw_type]->session_create)(net, tunnel_id,
- session_id, peer_session_id, &cfg);
+ ret = l2tp_nl_cmd_ops[cfg.pw_type]->session_create(net, tunnel,
+ session_id,
+ peer_session_id,
+ &cfg);
if (ret >= 0) {
session = l2tp_session_get(net, tunnel, session_id, false);
diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c
index f0edb7209079..50e3ee9a9d61 100644
--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -788,25 +788,20 @@ end:
#ifdef CONFIG_L2TP_V3
-/* Called when creating sessions via the netlink interface.
- */
-static int pppol2tp_session_create(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg)
+/* Called when creating sessions via the netlink interface. */
+static int pppol2tp_session_create(struct net *net, struct l2tp_tunnel *tunnel,
+ u32 session_id, u32 peer_session_id,
+ struct l2tp_session_cfg *cfg)
{
int error;
- struct l2tp_tunnel *tunnel;
struct l2tp_session *session;
struct pppol2tp_session *ps;
- tunnel = l2tp_tunnel_find(net, tunnel_id);
-
- /* Error if we can't find the tunnel */
- error = -ENOENT;
- if (tunnel == NULL)
- goto out;
-
/* Error if tunnel socket is not prepped */
- if (tunnel->sock == NULL)
+ if (!tunnel->sock) {
+ error = -ENOENT;
goto out;
+ }
/* Default MTU values. */
if (cfg->mtu == 0)