cifs: fix NULL pointer dereference in cifs_find_smb_ses

cifs_find_smb_ses assumes that the vol->password field is a valid
pointer, but that's only the case if a password was passed in via
the options string. It's possible that one won't be if there is
no mount helper on the box.

Reported-by: diabel <gacek-2004@wp.pl>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 95c2ea6..446e248 100644 (file)
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -1673,7 +1673,8 @@ cifs_find_smb_ses(struct TCP_Server_Info *server, struct smb_vol *vol)
                                    MAX_USERNAME_SIZE))
                                continue;
                        if (strlen(vol->username) != 0 &&
-                           strncmp(ses->password, vol->password,
+                           strncmp(ses->password,
+                                   vol->password ? vol->password : "",
                                    MAX_PASSWORD_SIZE))
                                continue;
                }