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/coda_linux.c b/fs/coda/coda_linux.c
index 854ace7..2849f41 100644
--- a/fs/coda/coda_linux.c
+++ b/fs/coda/coda_linux.c
@@ -100,9 +100,9 @@
if (attr->va_mode != (u_short) -1)
inode->i_mode = attr->va_mode | inode_type;
if (attr->va_uid != -1)
- inode->i_uid = (uid_t) attr->va_uid;
+ inode->i_uid = make_kuid(&init_user_ns, (uid_t) attr->va_uid);
if (attr->va_gid != -1)
- inode->i_gid = (gid_t) attr->va_gid;
+ inode->i_gid = make_kgid(&init_user_ns, (gid_t) attr->va_gid);
if (attr->va_nlink != -1)
set_nlink(inode, attr->va_nlink);
if (attr->va_size != -1)
@@ -171,10 +171,10 @@
vattr->va_mode = iattr->ia_mode;
}
if ( valid & ATTR_UID ) {
- vattr->va_uid = (vuid_t) iattr->ia_uid;
+ vattr->va_uid = (vuid_t) from_kuid(&init_user_ns, iattr->ia_uid);
}
if ( valid & ATTR_GID ) {
- vattr->va_gid = (vgid_t) iattr->ia_gid;
+ vattr->va_gid = (vgid_t) from_kgid(&init_user_ns, iattr->ia_gid);
}
if ( valid & ATTR_SIZE ) {
vattr->va_size = iattr->ia_size;