fs/cifs: correctly to anonymous authentication for the NTLM(v2) authentication

Only server which map unknown users to guest will allow
access using a non-null NTLMv2_Response.

For Samba it's the "map to guest = bad user" option.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=11913

Signed-off-by: Stefan Metzmacher <metze@samba.org>
CC: Stable <stable@vger.kernel.org>
Signed-off-by: Steve French <smfrench@gmail.com>

diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c
index 5d5d11ea0251fe8e663233a186c3b809dde70cda..af0ec2d5ad0e9da25af4ec8528266451a42cc8b5 100644 (file)
--- a/fs/cifs/sess.c
+++ b/fs/cifs/sess.c
@@ -895,22 +895,26 @@ sess_auth_ntlmv2(struct sess_data *sess_data)
        /* LM2 password would be here if we supported it */
        pSMB->req_no_secext.CaseInsensitivePasswordLength = 0;
 
-       /* calculate nlmv2 response and session key */
-       rc = setup_ntlmv2_rsp(ses, sess_data->nls_cp);
-       if (rc) {
-               cifs_dbg(VFS, "Error %d during NTLMv2 authentication\n", rc);
-               goto out;
-       }
+       if (ses->user_name != NULL) {
+               /* calculate nlmv2 response and session key */
+               rc = setup_ntlmv2_rsp(ses, sess_data->nls_cp);
+               if (rc) {
+                       cifs_dbg(VFS, "Error %d during NTLMv2 authentication\n", rc);
+                       goto out;
+               }
 
-       memcpy(bcc_ptr, ses->auth_key.response + CIFS_SESS_KEY_SIZE,
-                       ses->auth_key.len - CIFS_SESS_KEY_SIZE);
-       bcc_ptr += ses->auth_key.len - CIFS_SESS_KEY_SIZE;
+               memcpy(bcc_ptr, ses->auth_key.response + CIFS_SESS_KEY_SIZE,
+                               ses->auth_key.len - CIFS_SESS_KEY_SIZE);
+               bcc_ptr += ses->auth_key.len - CIFS_SESS_KEY_SIZE;
 
-       /* set case sensitive password length after tilen may get
-        * assigned, tilen is 0 otherwise.
-        */
-       pSMB->req_no_secext.CaseSensitivePasswordLength =
-               cpu_to_le16(ses->auth_key.len - CIFS_SESS_KEY_SIZE);
+               /* set case sensitive password length after tilen may get
+                * assigned, tilen is 0 otherwise.
+                */
+               pSMB->req_no_secext.CaseSensitivePasswordLength =
+                       cpu_to_le16(ses->auth_key.len - CIFS_SESS_KEY_SIZE);
+       } else {
+               pSMB->req_no_secext.CaseSensitivePasswordLength = 0;
+       }
 
        if (ses->capabilities & CAP_UNICODE) {
                if (sess_data->iov[0].iov_len % 2) {