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authorEric W. Biederman <ebiederm@xmission.com>2016-08-08 14:33:23 -0500
committerEric W. Biederman <ebiederm@xmission.com>2016-08-08 14:42:04 -0500
commit703286608a220d53584cca5986aad5305eec75ed (patch)
tree2f0476d44dcd98e891697ef7aaef9653b06b1b4e /net/core/net_namespace.c
parentcgroupns: Add a limit on the number of cgroup namespaces (diff)
downloadlinux-dev-703286608a220d53584cca5986aad5305eec75ed.tar.xz
linux-dev-703286608a220d53584cca5986aad5305eec75ed.zip
netns: Add a limit on the number of net namespaces
Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'net/core/net_namespace.c')
-rw-r--r--net/core/net_namespace.c22
1 files changed, 21 insertions, 1 deletions
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index 2c2eb1b629b1..3e2812aeceb7 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -266,6 +266,16 @@ struct net *get_net_ns_by_id(struct net *net, int id)
return peer;
}
+static struct ucounts *inc_net_namespaces(struct user_namespace *ns)
+{
+ return inc_ucount(ns, current_euid(), UCOUNT_NET_NAMESPACES);
+}
+
+static void dec_net_namespaces(struct ucounts *ucounts)
+{
+ dec_ucount(ucounts, UCOUNT_NET_NAMESPACES);
+}
+
/*
* setup_net runs the initializers for the network namespace object.
*/
@@ -351,19 +361,27 @@ void net_drop_ns(void *p)
struct net *copy_net_ns(unsigned long flags,
struct user_namespace *user_ns, struct net *old_net)
{
+ struct ucounts *ucounts;
struct net *net;
int rv;
if (!(flags & CLONE_NEWNET))
return get_net(old_net);
+ ucounts = inc_net_namespaces(user_ns);
+ if (!ucounts)
+ return ERR_PTR(-ENFILE);
+
net = net_alloc();
- if (!net)
+ if (!net) {
+ dec_net_namespaces(ucounts);
return ERR_PTR(-ENOMEM);
+ }
get_user_ns(user_ns);
mutex_lock(&net_mutex);
+ net->ucounts = ucounts;
rv = setup_net(net, user_ns);
if (rv == 0) {
rtnl_lock();
@@ -372,6 +390,7 @@ struct net *copy_net_ns(unsigned long flags,
}
mutex_unlock(&net_mutex);
if (rv < 0) {
+ dec_net_namespaces(ucounts);
put_user_ns(user_ns);
net_drop_ns(net);
return ERR_PTR(rv);
@@ -444,6 +463,7 @@ static void cleanup_net(struct work_struct *work)
/* Finally it is safe to free my network namespace structure */
list_for_each_entry_safe(net, tmp, &net_exit_list, exit_list) {
list_del_init(&net->exit_list);
+ dec_net_namespaces(net->ucounts);
put_user_ns(net->user_ns);
net_drop_ns(net);
}