1 files changed, 47 insertions, 14 deletions

diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c
index 100ae5641162..cd25d91895a1 100644
--- a/fs/nfsd/nfsfh.c
+++ b/fs/nfsd/nfsfh.c
@@ -51,7 +51,7 @@ static int nfsd_acceptable(void *expv, struct dentry *dentry)
 		/* make sure parents give x permission to user */
 		int err;
 		parent = dget_parent(tdentry);
-		err = permission(parent->d_inode, MAY_EXEC, NULL);
+		err = inode_permission(parent->d_inode, MAY_EXEC);
 		if (err < 0) {
 			dput(parent);
 			break;
@@ -176,9 +176,24 @@ static __be32 nfsd_set_fh_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp)
 	if (IS_ERR(exp))
 		return nfserrno(PTR_ERR(exp));
 
-	error = nfsd_setuser_and_check_port(rqstp, exp);
-	if (error)
-		goto out;
+	if (exp->ex_flags & NFSEXP_NOSUBTREECHECK) {
+		/* Elevate privileges so that the lack of 'r' or 'x'
+		 * permission on some parent directory will
+		 * not stop exportfs_decode_fh from being able
+		 * to reconnect a directory into the dentry cache.
+		 * The same problem can affect "SUBTREECHECK" exports,
+		 * but as nfsd_acceptable depends on correct
+		 * access control settings being in effect, we cannot
+		 * fix that case easily.
+		 */
+		current->cap_effective =
+			cap_raise_nfsd_set(current->cap_effective,
+					   current->cap_permitted);
+	} else {
+		error = nfsd_setuser_and_check_port(rqstp, exp);
+		if (error)
+			goto out;
+	}
 
 	/*
 	 * Look up the dentry using the NFS file handle.
@@ -215,6 +230,14 @@ static __be32 nfsd_set_fh_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp)
 		goto out;
 	}
 
+	if (exp->ex_flags & NFSEXP_NOSUBTREECHECK) {
+		error = nfsd_setuser_and_check_port(rqstp, exp);
+		if (error) {
+			dput(dentry);
+			goto out;
+		}
+	}
+
 	if (S_ISDIR(dentry->d_inode->i_mode) &&
 			(dentry->d_flags & DCACHE_DISCONNECTED)) {
 		printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
@@ -279,17 +302,27 @@ fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
 	if (error)
 		goto out;
 
-	if (!(access & MAY_LOCK)) {
-		/*
-		 * pseudoflavor restrictions are not enforced on NLM,
-		 * which clients virtually always use auth_sys for,
-		 * even while using RPCSEC_GSS for NFS.
-		 */
-		error = check_nfsd_access(exp, rqstp);
-		if (error)
-			goto out;
-	}
+	/*
+	 * pseudoflavor restrictions are not enforced on NLM,
+	 * which clients virtually always use auth_sys for,
+	 * even while using RPCSEC_GSS for NFS.
+	 */
+	if (access & NFSD_MAY_LOCK)
+		goto skip_pseudoflavor_check;
+	/*
+	 * Clients may expect to be able to use auth_sys during mount,
+	 * even if they use gss for everything else; see section 2.3.2
+	 * of rfc 2623.
+	 */
+	if (access & NFSD_MAY_BYPASS_GSS_ON_ROOT
+			&& exp->ex_path.dentry == dentry)
+		goto skip_pseudoflavor_check;
+
+	error = check_nfsd_access(exp, rqstp);
+	if (error)
+		goto out;
 
+skip_pseudoflavor_check:
 	/* Finally, check access permissions. */
 	error = nfsd_permission(rqstp, exp, dentry, access);