[PATCH] fs: lockd: avoid possible wrong NULL parameter

[Su Hui]

clang's static analysis warning: fs/lockd/mon.c: line 293, column 2:
Null pointer passed as 2nd argument to memory copy function.

Assuming 'hostname' is NULL and calling 'nsm_create_handle()', this will
pass NULL as 2nd argument to memory copy function 'memcpy()'. So return
NULL if 'hostname' is invalid.

Fixes: 77a3ef33e2de ("NSM: More clean up of nsm_get_handle()")
Signed-off-by: Su Hui <suhui@xxxxxxxxxxxx>
---
 fs/lockd/mon.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/lockd/mon.c b/fs/lockd/mon.c
index 1d9488cf0534..eebab013e063 100644
--- a/fs/lockd/mon.c
+++ b/fs/lockd/mon.c
@@ -358,6 +358,9 @@ struct nsm_handle *nsm_get_handle(const struct net *net,
 
 	spin_unlock(&nsm_lock);
 
+	if (!hostname)
+		return NULL;
+
 	new = nsm_create_handle(sap, salen, hostname, hostname_len);
 	if (unlikely(new == NULL))
 		return NULL;
-- 
2.30.2