[PATCH 3.16 095/305] fs/cifs: correctly to anonymous authentication for the NTLM(v2) authentication

Ben Hutchings
2016-08-14T11:59:41Z

From: Stefan Metzmacher <metze@samba.org>

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 3.16:adjust context, indentation]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
--- a/fs/cifs/sess.c
+++ b/fs/cifs/sess.c
@@ -703,22 +703,26 @@ 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) {
- cifs_dbg(VFS, "Error %d during NTLMv2 authentication\n",
- 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) {
+ cifs_dbg(VFS, "Error %d during NTLMv2 authentication\n", 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;

- /* 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 (iov[0].iov_len % 2) {