1 files changed, 110 insertions, 3 deletions

diff --git a/fs/nfs/namespace.c b/fs/nfs/namespace.c
index b02720864ded..ad92bf731ff5 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 @@ int nfs_mountpoint_expiry_timeout = 500 * HZ;
 
 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 @@ Elong:
         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 vfsmount *nfs_d_automount(struct path *path)
         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 @@ struct vfsmount *nfs_d_automount(struct path *path)
         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 @@ struct vfsmount *nfs_d_automount(struct path *path)
         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 @@ static struct vfsmount *nfs_do_clone_mount(struct nfs_server *server,
  * @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);