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

commit 1a967d6c9b39c226be1b45f13acd4d8a5ab3dc44 upstream.

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>
Signed-off-by: Steve French <smfrench@gmail.com>
[bwh: Backported to 3.2:
 - Adjust context, indentation
 - Keep using cERROR()]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c
index d440e40..8dbfa3e 100644 (file)
--- a/fs/cifs/sess.c
+++ b/fs/cifs/sess.c
@@ -727,21 +727,26 @@ ssetup_ntlmssp_authenticate:
                /* 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, nls_cp);
-               if (rc) {
-                       cERROR(1, "Error %d during NTLMv2 authentication", rc);
-                       goto ssetup_exit;
-               }
-               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;
+               if (ses->user_name != NULL) {
+                       /* calculate nlmv2 response and session key */
+                       rc = setup_ntlmv2_rsp(ses, nls_cp);
+                       if (rc) {
+                               cERROR(1, "Error %d during NTLMv2 authentication", rc);
+                               goto ssetup_exit;
+                       }
 
-               /* 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);
+                       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);
+               } else {
+                       pSMB->req_no_secext.CaseSensitivePasswordLength = 0;
+               }
 
                if (ses->capabilities & CAP_UNICODE) {
                        if (iov[0].iov_len % 2) {