[PATCH] nfsd/idmap: return nfserr_inval for zero length principals

[Kinglong Mee <kinglongmee@gmail.com>]

Tigran Mkrtchyan's pynfs testcase for zero length principals fail as,

SATT16   st_setattr.testEmptyPrincipal                            : FAILURE
           Setting empty owner should return NFS4ERR_INVAL,
           instead got NFS4ERR_BADOWNER
SATT17   st_setattr.testEmptyGroupPrincipal                       : FAILURE
           Setting empty owner_group should return NFS4ERR_INVAL,
           instead got NFS4ERR_BADOWNER

This patch checks the principal and return nfserr_inval directly.
It should be check after decoding in nfs4xdr.c, but it's simple before
process in nfsd_map_xxxx, so adds it in nfs4idmap.c.

Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
---
 fs/nfsd/nfs4idmap.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/fs/nfsd/nfs4idmap.c b/fs/nfsd/nfs4idmap.c
index 5b20577..6b9b6cc 100644
--- a/fs/nfsd/nfs4idmap.c
+++ b/fs/nfsd/nfs4idmap.c
@@ -628,6 +628,10 @@ nfsd_map_name_to_uid(struct svc_rqst *rqstp, const char *name, size_t namelen,
 {
 	__be32 status;
 	u32 id = -1;
+
+	if (name == NULL || namelen == 0)
+		return nfserr_inval;
+
 	status = do_name_to_id(rqstp, IDMAP_TYPE_USER, name, namelen, &id);
 	*uid = make_kuid(&init_user_ns, id);
 	if (!uid_valid(*uid))
@@ -641,6 +645,10 @@ nfsd_map_name_to_gid(struct svc_rqst *rqstp, const char *name, size_t namelen,
 {
 	__be32 status;
 	u32 id = -1;
+
+	if (name == NULL || namelen == 0)
+		return nfserr_inval;
+
 	status = do_name_to_id(rqstp, IDMAP_TYPE_GROUP, name, namelen, &id);
 	*gid = make_kgid(&init_user_ns, id);
 	if (!gid_valid(*gid))
-- 
2.9.3