X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=kernel%2Fuser_namespace.c;h=7af90fc4f0fd3d870c1f5dbb3b0771fc16bbc5a4;hb=5ef43567c55c758c651f8339d01678f12d54ac2a;hp=3d79642097748c0b89ad2ac4c3141ab601489fcb;hpb=acce292c82d4d82d35553b928df2b0597c3a9c78;p=linux-2.6

diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index 3d79642097..7af90fc4f0 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -21,6 +21,45 @@ EXPORT_SYMBOL_GPL(init_user_ns);
 
 #ifdef CONFIG_USER_NS
 
+/*
+ * Clone a new ns copying an original user ns, setting refcount to 1
+ * @old_ns: namespace to clone
+ * Return NULL on error (failure to kmalloc), new ns otherwise
+ */
+static struct user_namespace *clone_user_ns(struct user_namespace *old_ns)
+{
+	struct user_namespace *ns;
+	struct user_struct *new_user;
+	int n;
+
+	ns = kmalloc(sizeof(struct user_namespace), GFP_KERNEL);
+	if (!ns)
+		return ERR_PTR(-ENOMEM);
+
+	kref_init(&ns->kref);
+
+	for (n = 0; n < UIDHASH_SZ; ++n)
+		INIT_HLIST_HEAD(ns->uidhash_table + n);
+
+	/* Insert new root user.  */
+	ns->root_user = alloc_uid(ns, 0);
+	if (!ns->root_user) {
+		kfree(ns);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	/* Reset current->user with a new one */
+	new_user = alloc_uid(ns, current->uid);
+	if (!new_user) {
+		free_uid(ns->root_user);
+		kfree(ns);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	switch_uid(new_user);
+	return ns;
+}
+
 struct user_namespace * copy_user_ns(int flags, struct user_namespace *old_ns)
 {
 	struct user_namespace *new_ns;
@@ -28,7 +67,12 @@ struct user_namespace * copy_user_ns(int flags, struct user_namespace *old_ns)
 	BUG_ON(!old_ns);
 	get_user_ns(old_ns);
 
-	new_ns = old_ns;
+	if (!(flags & CLONE_NEWUSER))
+		return old_ns;
+
+	new_ns = clone_user_ns(old_ns);
+
+	put_user_ns(old_ns);
 	return new_ns;
 }
 
@@ -37,6 +81,7 @@ void free_user_ns(struct kref *kref)
 	struct user_namespace *ns;
 
 	ns = container_of(kref, struct user_namespace, kref);
+	release_uids(ns);
 	kfree(ns);
 }