NFS: use secinfo when crossing mountpoints
A submount may use different security than the parent
mount does. We should figure out what sec flavor the
submount uses at mount time.
Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/namespace.c b/fs/nfs/namespace.c
index b027208..ad92bf7 100644
--- a/fs/nfs/namespace.c
+++ b/fs/nfs/namespace.c
@@ -15,6 +15,7 @@
#include <linux/string.h>
#include <linux/sunrpc/clnt.h>
#include <linux/vfs.h>
+#include <linux/sunrpc/gss_api.h>
#include "internal.h"
#define NFSDBG_FACILITY NFSDBG_VFS
@@ -27,7 +28,8 @@
static struct vfsmount *nfs_do_submount(struct dentry *dentry,
struct nfs_fh *fh,
- struct nfs_fattr *fattr);
+ struct nfs_fattr *fattr,
+ rpc_authflavor_t authflavor);
/*
* nfs_path - reconstruct the path given an arbitrary dentry
@@ -116,6 +118,100 @@
return ERR_PTR(-ENAMETOOLONG);
}
+#ifdef CONFIG_NFS_V4
+static rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *flavors, struct inode *inode)
+{
+ struct gss_api_mech *mech;
+ struct xdr_netobj oid;
+ int i;
+ rpc_authflavor_t pseudoflavor = RPC_AUTH_UNIX;
+
+ for (i = 0; i < flavors->num_flavors; i++) {
+ struct nfs4_secinfo_flavor *flavor;
+ flavor = &flavors->flavors[i];
+
+ if (flavor->flavor == RPC_AUTH_NULL || flavor->flavor == RPC_AUTH_UNIX) {
+ pseudoflavor = flavor->flavor;
+ break;
+ } else if (flavor->flavor == RPC_AUTH_GSS) {
+ oid.len = flavor->gss.sec_oid4.len;
+ oid.data = flavor->gss.sec_oid4.data;
+ mech = gss_mech_get_by_OID(&oid);
+ if (!mech)
+ continue;
+ pseudoflavor = gss_svc_to_pseudoflavor(mech, flavor->gss.service);
+ gss_mech_put(mech);
+ break;
+ }
+ }
+
+ return pseudoflavor;
+}
+
+static rpc_authflavor_t nfs_negotiate_security(const struct dentry *parent, const struct dentry *dentry)
+{
+ int status = 0;
+ struct page *page;
+ struct nfs4_secinfo_flavors *flavors;
+ int (*secinfo)(struct inode *, const struct qstr *, struct nfs4_secinfo_flavors *);
+ rpc_authflavor_t flavor = RPC_AUTH_UNIX;
+
+ secinfo = NFS_PROTO(parent->d_inode)->secinfo;
+ if (secinfo != NULL) {
+ page = alloc_page(GFP_KERNEL);
+ if (!page) {
+ status = -ENOMEM;
+ goto out;
+ }
+ flavors = page_address(page);
+ status = secinfo(parent->d_inode, &dentry->d_name, flavors);
+ flavor = nfs_find_best_sec(flavors, dentry->d_inode);
+ put_page(page);
+ }
+
+ return flavor;
+
+out:
+ status = -ENOMEM;
+ return status;
+}
+
+static rpc_authflavor_t nfs_lookup_with_sec(struct nfs_server *server, struct dentry *parent,
+ struct dentry *dentry, struct path *path,
+ struct nfs_fh *fh, struct nfs_fattr *fattr)
+{
+ rpc_authflavor_t flavor;
+ struct rpc_clnt *clone;
+ struct rpc_auth *auth;
+ int err;
+
+ flavor = nfs_negotiate_security(parent, path->dentry);
+ if (flavor < 0)
+ goto out;
+ clone = rpc_clone_client(server->client);
+ auth = rpcauth_create(flavor, clone);
+ if (!auth) {
+ flavor = -EIO;
+ goto out;
+ }
+ err = server->nfs_client->rpc_ops->lookup(clone, parent->d_inode,
+ &path->dentry->d_name,
+ fh, fattr);
+ if (err < 0)
+ flavor = err;
+out:
+ return flavor;
+}
+#else /* CONFIG_NFS_V4 */
+static inline rpc_authflavor_t nfs_lookup_with_sec(struct nfs_server *server,
+ struct dentry *parent, struct dentry *dentry,
+ struct path *path, struct nfs_fh *fh,
+ struct nfs_fattr *fattr)
+{
+ return -EPERM;
+}
+#endif /* CONFIG_NFS_V4 */
+
/*
* nfs_d_automount - Handle crossing a mountpoint on the server
* @path - The mountpoint
@@ -136,6 +232,7 @@
struct nfs_fh *fh = NULL;
struct nfs_fattr *fattr = NULL;
int err;
+ rpc_authflavor_t flavor = 1;
dprintk("--> nfs_d_automount()\n");
@@ -156,6 +253,13 @@
err = server->nfs_client->rpc_ops->lookup(server->client, parent->d_inode,
&path->dentry->d_name,
fh, fattr);
+ if (err == -EPERM) {
+ flavor = nfs_lookup_with_sec(server, parent, path->dentry, path, fh, fattr);
+ if (flavor < 0)
+ err = flavor;
+ else
+ err = 0;
+ }
dput(parent);
if (err != 0) {
mnt = ERR_PTR(err);
@@ -165,7 +269,7 @@
if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL)
mnt = nfs_do_refmount(path->dentry);
else
- mnt = nfs_do_submount(path->dentry, fh, fattr);
+ mnt = nfs_do_submount(path->dentry, fh, fattr, flavor);
if (IS_ERR(mnt))
goto out;
@@ -232,17 +336,20 @@
* @dentry - parent directory
* @fh - filehandle for new root dentry
* @fattr - attributes for new root inode
+ * @authflavor - security flavor to use when performing the mount
*
*/
static struct vfsmount *nfs_do_submount(struct dentry *dentry,
struct nfs_fh *fh,
- struct nfs_fattr *fattr)
+ struct nfs_fattr *fattr,
+ rpc_authflavor_t authflavor)
{
struct nfs_clone_mount mountdata = {
.sb = dentry->d_sb,
.dentry = dentry,
.fh = fh,
.fattr = fattr,
+ .authflavor = authflavor,
};
struct vfsmount *mnt = ERR_PTR(-ENOMEM);
char *page = (char *) __get_free_page(GFP_USER);