coda: Restrict coda messages to the initial user namespace
Remove the slight chance that uids and gids in coda messages will be
interpreted in the wrong user namespace.
- Only allow processes in the initial user namespace to open the coda
character device to communicate with coda filesystems.
- Explicitly convert the uids in the coda header into the initial user
namespace.
- In coda_vattr_to_attr make kuids and kgids from the initial user
namespace uids and gids in struct coda_vattr that just came from
userspace.
- In coda_iattr_to_vattr convert kuids and kgids into uids and gids
in the intial user namespace and store them in struct coda_vattr for
sending to coda userspace programs.
Nothing needs to be changed with mounts as coda does not support
being mounted in anything other than the initial user namespace.
Cc: Jan Harkes <jaharkes@cs.cmu.edu>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
diff --git a/fs/coda/psdev.c b/fs/coda/psdev.c
index dd60f90..ebc2bae 100644
--- a/fs/coda/psdev.c
+++ b/fs/coda/psdev.c
@@ -270,6 +270,9 @@
if (task_active_pid_ns(current) != &init_pid_ns)
return -EINVAL;
+ if (current_user_ns() != &init_user_ns)
+ return -EINVAL;
+
idx = iminor(inode);
if (idx < 0 || idx >= MAX_CODADEVS)
return -ENODEV;