Merge tag 'drm-for-v4.9' of git://people.freedesktop.org/~airlied/linux

[cascardo/linux.git] / kernel / pid_namespace.c

diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index a65ba13..df9e8e9 100644 (file)
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -79,23 +79,36 @@ static void proc_cleanup_work(struct work_struct *work)
 /* MAX_PID_NS_LEVEL is needed for limiting size of 'struct pid' */
 #define MAX_PID_NS_LEVEL 32
 
+static struct ucounts *inc_pid_namespaces(struct user_namespace *ns)
+{
+       return inc_ucount(ns, current_euid(), UCOUNT_PID_NAMESPACES);
+}
+
+static void dec_pid_namespaces(struct ucounts *ucounts)
+{
+       dec_ucount(ucounts, UCOUNT_PID_NAMESPACES);
+}
+
 static struct pid_namespace *create_pid_namespace(struct user_namespace *user_ns,
        struct pid_namespace *parent_pid_ns)
 {
        struct pid_namespace *ns;
        unsigned int level = parent_pid_ns->level + 1;
+       struct ucounts *ucounts;
        int i;
        int err;
 
-       if (level > MAX_PID_NS_LEVEL) {
-               err = -EINVAL;
+       err = -ENOSPC;
+       if (level > MAX_PID_NS_LEVEL)
+               goto out;
+       ucounts = inc_pid_namespaces(user_ns);
+       if (!ucounts)
                goto out;
-       }
 
        err = -ENOMEM;
        ns = kmem_cache_zalloc(pid_ns_cachep, GFP_KERNEL);
        if (ns == NULL)
-               goto out;
+               goto out_dec;
 
        ns->pidmap[0].page = kzalloc(PAGE_SIZE, GFP_KERNEL);
        if (!ns->pidmap[0].page)
@@ -114,6 +127,7 @@ static struct pid_namespace *create_pid_namespace(struct user_namespace *user_ns
        ns->level = level;
        ns->parent = get_pid_ns(parent_pid_ns);
        ns->user_ns = get_user_ns(user_ns);
+       ns->ucounts = ucounts;
        ns->nr_hashed = PIDNS_HASH_ADDING;
        INIT_WORK(&ns->proc_work, proc_cleanup_work);
 
@@ -129,6 +143,8 @@ out_free_map:
        kfree(ns->pidmap[0].page);
 out_free:
        kmem_cache_free(pid_ns_cachep, ns);
+out_dec:
+       dec_pid_namespaces(ucounts);
 out:
        return ERR_PTR(err);
 }
@@ -146,6 +162,7 @@ static void destroy_pid_namespace(struct pid_namespace *ns)
        ns_free_inum(&ns->ns);
        for (i = 0; i < PIDMAP_ENTRIES; i++)
                kfree(ns->pidmap[i].page);
+       dec_pid_namespaces(ns->ucounts);
        put_user_ns(ns->user_ns);
        call_rcu(&ns->rcu, delayed_free_pidns);
 }
@@ -388,12 +405,37 @@ static int pidns_install(struct nsproxy *nsproxy, struct ns_common *ns)
        return 0;
 }
 
+static struct ns_common *pidns_get_parent(struct ns_common *ns)
+{
+       struct pid_namespace *active = task_active_pid_ns(current);
+       struct pid_namespace *pid_ns, *p;
+
+       /* See if the parent is in the current namespace */
+       pid_ns = p = to_pid_ns(ns)->parent;
+       for (;;) {
+               if (!p)
+                       return ERR_PTR(-EPERM);
+               if (p == active)
+                       break;
+               p = p->parent;
+       }
+
+       return &get_pid_ns(pid_ns)->ns;
+}
+
+static struct user_namespace *pidns_owner(struct ns_common *ns)
+{
+       return to_pid_ns(ns)->user_ns;
+}
+
 const struct proc_ns_operations pidns_operations = {
        .name           = "pid",
        .type           = CLONE_NEWPID,
        .get            = pidns_get,
        .put            = pidns_put,
        .install        = pidns_install,
+       .owner          = pidns_owner,
+       .get_parent     = pidns_get_parent,
 };
 
 static __init int pid_namespaces_init(void)