[CIFS] Support for setting up SMB sessions to legacy lanman servers

fs/cifs/cifsencrypt.c

diff --git a/fs/cifs/cifsencrypt.c b/fs/cifs/cifsencrypt.c
index e7d6373..08781a4 100644
--- a/fs/cifs/cifsencrypt.c
+++ b/fs/cifs/cifsencrypt.c
@@ -225,6 +225,8 @@
 	user_name_len = strlen(ses->userName);
 	if(user_name_len > MAX_USERNAME_SIZE)
 		return -EINVAL;
+	if(ses->domainName == NULL)
+		return -EINVAL; /* BB should we use CIFS_LINUX_DOM */
 	dom_name_len = strlen(ses->domainName);
 	if(dom_name_len > MAX_USERNAME_SIZE)
 		return -EINVAL;