[CIFS] Support for older servers which require plaintext passwords

disabled by default, but can be enabled via proc for servers which
require such support.  Also includes support for setting security
flags for cifs.  See fs/cifs/README

Signed-off-by: Steve French <sfrench@us.ibm.com>

fs/cifs/cifssmb.c

@@ -492,6 +492,13 @@ CIFSSMBNegotiate(unsigned int xid, struct cifsSesInfo *ses)
 		server->secMode = pSMBr->SecurityMode;
 		if((server->secMode & SECMODE_USER) == 0)
 			cFYI(1,("share mode security"));
+
+		if((server->secMode & SECMODE_PW_ENCRYPT) == 0)
+#ifdef CONFIG_CIFS_WEAK_PW_HASH
+			if ((extended_security & CIFSSEC_MAY_PLNTXT) == 0)
+#endif /* CIFS_WEAK_PW_HASH */
+				cERROR(1,("Server requests plain text password"
+					" but client support disabled"));
 		
 		if(extended_security & CIFSSEC_MUST_NTLMV2)
 			server->secType = NTLMv2;