[nfs-utils PATCH] mount: reject "namlen=" option for a NFSv4 mount

From: Chen Hanxiao <chenhx.fnst@fujitsu.com>
To: Steve Dickson <steved@redhat.com>
Cc: linux-nfs@vger.kernel.org
Subject: [nfs-utils PATCH] mount: reject "namlen=" option for a NFSv4 mount
Date: Fri, 22 Mar 2024 18:36:18 +0800	[thread overview]
Message-ID: <20240322103618.1270-1-chenhx.fnst@fujitsu.com> (raw)

namlen is not a valid option for NFSv4.
Currently, we could pass a namlen=xxx in a NFSv4 mount,
the mount command succeed and namlen is ignored silently

# mount -o vers=4,namlen=100 192.168.122.19:/nfsroot /mnt/ -vvv
mount.nfs: timeout set for Fri Mar 22 14:22:18 2024
mount.nfs: trying text-based options 'namlen=100,vers=4.2,
	   addr=192.168.122.19,clientaddr=192.168.122.15'

This patch reject "namlen=" option in a NFSv4 mount.

Signed-off-by: Chen Hanxiao <chenhx.fnst@fujitsu.com>
---
 utils/mount/stropts.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/utils/mount/stropts.c b/utils/mount/stropts.c
index dbdd11e7..028ff6a6 100644
--- a/utils/mount/stropts.c
+++ b/utils/mount/stropts.c
@@ -780,6 +780,15 @@ static int nfs_do_mount_v4(struct nfsmount_info *mi,
 		goto out_fail;
 	}
 
+	if (po_contains(options, "namlen")) {
+		if (verbose) {
+			printf(_("%s: Unsupported nfs4 mount option(s) passed '%s'\n"),
+				progname, *mi->extra_opts);
+		}
+		errno = EINVAL;
+		goto out_fail;
+	}
+
 	if (mi->version.v_mode != V_SPECIFIC) {
 		char *fmt;
 		switch (mi->version.minor) {
-- 
2.39.1

