From: Eric W. Biederman Date: Mon, 23 Sep 2013 21:41:17 +0000 (-0700) Subject: sysfs: Allow mounting without CONFIG_NET X-Git-Tag: firefly_0821_release~176^2~5227^2~1 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=667b4102b3e63856ca7770521ee74b1c44629df1;p=firefly-linux-kernel-4.4.55.git sysfs: Allow mounting without CONFIG_NET In kobj_ns_current_may_mount the default should be to allow the mount. The test is only for a single kobj_ns_type at a time, and unless there is a reason to prevent it the mounting sysfs should be allowed. Subsystems that are not registered can't have are not involved so can't have a reason to prevent mounting sysfs. This is a bug-fix to: commit 7dc5dbc879bd0779924b5132a48b731a0bc04a1e Author: Eric W. Biederman Date: Mon Mar 25 20:07:01 2013 -0700 sysfs: Restrict mounting sysfs Don't allow mounting sysfs unless the caller has CAP_SYS_ADMIN rights over the net namespace. The principle here is if you create or have capabilities over it you can mount it, otherwise you get to live with what other people have mounted. Instead of testing this with a straight forward ns_capable call, perform this check the long and torturous way with kobject helpers, this keeps direct knowledge of namespaces out of sysfs, and preserves the existing sysfs abstractions. Acked-by: Greg Kroah-Hartman Signed-off-by: "Eric W. Biederman" That came in via the userns tree during the 3.12 merge window. Reported-by: James Hogan Signed-off-by: "Eric W. Biederman" Signed-off-by: Greg Kroah-Hartman --- diff --git a/lib/kobject.c b/lib/kobject.c index 962175134702..669bf190d4fb 100644 --- a/lib/kobject.c +++ b/lib/kobject.c @@ -933,10 +933,7 @@ const struct kobj_ns_type_operations *kobj_ns_ops(struct kobject *kobj) bool kobj_ns_current_may_mount(enum kobj_ns_type type) { - bool may_mount = false; - - if (type == KOBJ_NS_TYPE_NONE) - return true; + bool may_mount = true; spin_lock(&kobj_ns_type_lock); if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&