fs/cifs: correctly to anonymous authentication for the NTLM(v1) authentication

commit 777f69b8d26bf35ade4a76b08f203c11e048365d upstream.

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

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 587037f..d440e40 100644 (file)
--- a/fs/cifs/sess.c
+++ b/fs/cifs/sess.c
@@ -686,26 +686,32 @@ ssetup_ntlmssp_authenticate:
 #endif
        } else if (type == NTLM) {
                pSMB->req_no_secext.Capabilities = cpu_to_le32(capabilities);
-               pSMB->req_no_secext.CaseInsensitivePasswordLength =
-                       cpu_to_le16(CIFS_AUTH_RESP_SIZE);
-               pSMB->req_no_secext.CaseSensitivePasswordLength =
-                       cpu_to_le16(CIFS_AUTH_RESP_SIZE);
+               if (ses->user_name != NULL) {
+                       pSMB->req_no_secext.CaseInsensitivePasswordLength =
+                                       cpu_to_le16(CIFS_AUTH_RESP_SIZE);
+                       pSMB->req_no_secext.CaseSensitivePasswordLength =
+                                       cpu_to_le16(CIFS_AUTH_RESP_SIZE);
+
+                       /* calculate ntlm response and session key */
+                       rc = setup_ntlm_response(ses, nls_cp);
+                       if (rc) {
+                               cERROR(1, "Error %d during NTLM authentication",
+                                                rc);
+                               goto ssetup_exit;
+                       }
 
-               /* calculate ntlm response and session key */
-               rc = setup_ntlm_response(ses, nls_cp);
-               if (rc) {
-                       cERROR(1, "Error %d during NTLM authentication", rc);
-                       goto ssetup_exit;
+                       /* copy ntlm response */
+                       memcpy(bcc_ptr, ses->auth_key.response + CIFS_SESS_KEY_SIZE,
+                                       CIFS_AUTH_RESP_SIZE);
+                       bcc_ptr += CIFS_AUTH_RESP_SIZE;
+                       memcpy(bcc_ptr, ses->auth_key.response + CIFS_SESS_KEY_SIZE,
+                                       CIFS_AUTH_RESP_SIZE);
+                       bcc_ptr += CIFS_AUTH_RESP_SIZE;
+               } else {
+                       pSMB->req_no_secext.CaseInsensitivePasswordLength = 0;
+                       pSMB->req_no_secext.CaseSensitivePasswordLength = 0;
                }
 
-               /* copy ntlm response */
-               memcpy(bcc_ptr, ses->auth_key.response + CIFS_SESS_KEY_SIZE,
-                               CIFS_AUTH_RESP_SIZE);
-               bcc_ptr += CIFS_AUTH_RESP_SIZE;
-               memcpy(bcc_ptr, ses->auth_key.response + CIFS_SESS_KEY_SIZE,
-                               CIFS_AUTH_RESP_SIZE);
-               bcc_ptr += CIFS_AUTH_RESP_SIZE;
-
                if (ses->capabilities & CAP_UNICODE) {
                        /* unicode strings must be word aligned */
                        if (iov[0].iov_len % 2) {