ceph: Only allow mounts in the initial network namespace

Today ceph opens tcp sockets from a delayed work callback.  Delayed
work happens from kernel threads which are always in the initial
network namespace.   Therefore fail early if someone attempts
to mount a ceph filesystem from something other than the initial
network namespace.

Cc: Sage Weil <sage@inktank.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/net/ceph/ceph_common.c b/net/ceph/ceph_common.c
index ee71ea26777a..1deb29af82fd 100644
--- a/net/ceph/ceph_common.c
+++ b/net/ceph/ceph_common.c
@@ -15,6 +15,8 @@
 #include <linux/slab.h>
 #include <linux/statfs.h>
 #include <linux/string.h>
+#include <linux/nsproxy.h>
+#include <net/net_namespace.h>
 
 
 #include <linux/ceph/ceph_features.h>
@@ -292,6 +294,9 @@ ceph_parse_options(char *options, const char *dev_name,
         int err = -ENOMEM;
         substring_t argstr[MAX_OPT_ARGS];
 
+        if (current->nsproxy->net_ns != &init_net)
+                return ERR_PTR(-EINVAL);
+
         opt = kzalloc(sizeof(*opt), GFP_KERNEL);
         if (!opt)
                 return ERR_PTR(-ENOMEM);