fs/cifs: correctly to anonymous authentication via NTLMSSP

See [MS-NLMP] 3.2.5.1.2 Server Receives an AUTHENTICATE_MESSAGE from the Client:

   ...
   Set NullSession to FALSE
   If (AUTHENTICATE_MESSAGE.UserNameLen == 0 AND
      AUTHENTICATE_MESSAGE.NtChallengeResponse.Length == 0 AND
      (AUTHENTICATE_MESSAGE.LmChallengeResponse == Z(1)
       OR
       AUTHENTICATE_MESSAGE.LmChallengeResponse.Length == 0))
       -- Special case: client requested anonymous authentication
       Set NullSession to TRUE
   ...

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

CC: Stable <stable@vger.kernel.org>
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>
This commit is contained in:
Stefan Metzmacher 2016-05-03 10:52:30 +02:00 committed by Steve French
parent 11e31647c9
commit cfda35d982

View File

@ -400,19 +400,27 @@ int build_ntlmssp_auth_blob(unsigned char *pbuffer,
sec_blob->LmChallengeResponse.MaximumLength = 0;
sec_blob->NtChallengeResponse.BufferOffset = cpu_to_le32(tmp - pbuffer);
rc = setup_ntlmv2_rsp(ses, nls_cp);
if (rc) {
cifs_dbg(VFS, "Error %d during NTLMSSP authentication\n", rc);
goto setup_ntlmv2_ret;
}
memcpy(tmp, ses->auth_key.response + CIFS_SESS_KEY_SIZE,
ses->auth_key.len - CIFS_SESS_KEY_SIZE);
tmp += ses->auth_key.len - CIFS_SESS_KEY_SIZE;
if (ses->user_name != NULL) {
rc = setup_ntlmv2_rsp(ses, nls_cp);
if (rc) {
cifs_dbg(VFS, "Error %d during NTLMSSP authentication\n", rc);
goto setup_ntlmv2_ret;
}
memcpy(tmp, ses->auth_key.response + CIFS_SESS_KEY_SIZE,
ses->auth_key.len - CIFS_SESS_KEY_SIZE);
tmp += ses->auth_key.len - CIFS_SESS_KEY_SIZE;
sec_blob->NtChallengeResponse.Length =
cpu_to_le16(ses->auth_key.len - CIFS_SESS_KEY_SIZE);
sec_blob->NtChallengeResponse.MaximumLength =
cpu_to_le16(ses->auth_key.len - CIFS_SESS_KEY_SIZE);
sec_blob->NtChallengeResponse.Length =
cpu_to_le16(ses->auth_key.len - CIFS_SESS_KEY_SIZE);
sec_blob->NtChallengeResponse.MaximumLength =
cpu_to_le16(ses->auth_key.len - CIFS_SESS_KEY_SIZE);
} else {
/*
* don't send an NT Response for anonymous access
*/
sec_blob->NtChallengeResponse.Length = 0;
sec_blob->NtChallengeResponse.MaximumLength = 0;
}
if (ses->domainName == NULL) {
sec_blob->DomainName.BufferOffset = cpu_to_le32(tmp - pbuffer);