From 7dc5dbc879bd0779924b5132a48b731a0bc04a1e Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Mon, 25 Mar 2013 20:07:01 -0700 Subject: 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" --- fs/sysfs/mount.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) (limited to 'fs/sysfs/mount.c') diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c index 4a2da3a4b1b1..8c69ef49c7f3 100644 --- a/fs/sysfs/mount.c +++ b/fs/sysfs/mount.c @@ -112,9 +112,15 @@ static struct dentry *sysfs_mount(struct file_system_type *fs_type, struct super_block *sb; int error; - if (!(flags & MS_KERNMOUNT) && !capable(CAP_SYS_ADMIN) && - !fs_fully_visible(fs_type)) - return ERR_PTR(-EPERM); + if (!(flags & MS_KERNMOUNT)) { + if (!capable(CAP_SYS_ADMIN) && !fs_fully_visible(fs_type)) + return ERR_PTR(-EPERM); + + for (type = KOBJ_NS_TYPE_NONE; type < KOBJ_NS_TYPES; type++) { + if (!kobj_ns_current_may_mount(type)) + return ERR_PTR(-EPERM); + } + } info = kzalloc(sizeof(*info), GFP_KERNEL); if (!info) -- cgit v1.2.3-59-g8ed1b