+/*
+ * chap_ms.c - Microsoft MS-CHAP compatible implementation.
+ *
+ * Copyright (c) 1995 Eric Rosenquist, Strata Software Limited.
+ * http://www.strataware.com/
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by Eric Rosenquist. The name of the author may not be used to
+ * endorse or promote products derived from this software without
+ * specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+#ifndef lint
+static char rcsid[] = "$Id: chap_ms.c,v 1.1 1996/05/28 00:42:30 paulus Exp $";
+#endif
+
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/time.h>
+#include <syslog.h>
+
+#include "pppd.h"
+#include "chap.h"
+#include "chap_ms.h"
+#include "md4.h"
+
+
+#ifdef CHAPMS
+#include <des.h>
+
+typedef struct {
+ u_char LANManResp[24];
+ u_char NTResp[24];
+ u_char UseNT; /* If 1, ignore the LANMan response field */
+} MS_ChapResponse;
+/* We use MS_CHAP_RESPONSE_LEN, rather than sizeof(MS_ChapResponse),
+ in case this struct gets padded. */
+
+
+static void DesEncrypt __P((u_char *, u_char *, u_char *));
+static void MakeKey __P((u_char *, u_char *));
+
+
+static void
+ChallengeResponse(challenge, pwHash, response)
+ u_char *challenge; /* IN 8 octets */
+ u_char *pwHash; /* IN 16 octets */
+ u_char *response; /* OUT 24 octets */
+{
+ char ZPasswordHash[21];
+
+ BZERO(ZPasswordHash, sizeof(ZPasswordHash));
+ BCOPY(pwHash, ZPasswordHash, 16);
+
+#if 0
+ log_packet(ZPasswordHash, sizeof(ZPasswordHash), "ChallengeResponse - ZPasswordHash");
+#endif
+
+ DesEncrypt(challenge, ZPasswordHash + 0, response + 0);
+ DesEncrypt(challenge, ZPasswordHash + 7, response + 8);
+ DesEncrypt(challenge, ZPasswordHash + 14, response + 16);
+
+#if 0
+ log_packet(response, 24, "ChallengeResponse - response");
+#endif
+}
+
+
+static void
+DesEncrypt(clear, key, cipher)
+ u_char *clear; /* IN 8 octets */
+ u_char *key; /* IN 7 octets */
+ u_char *cipher; /* OUT 8 octets */
+{
+ des_cblock des_key;
+ des_key_schedule key_schedule;
+
+ MakeKey(key, des_key);
+
+ des_set_key(&des_key, key_schedule);
+
+#if 0
+ CHAPDEBUG((LOG_INFO, "DesEncrypt: 8 octet input : %02X%02X%02X%02X%02X%02X%02X%02X",
+ clear[0], clear[1], clear[2], clear[3], clear[4], clear[5], clear[6], clear[7]));
+#endif
+
+ des_ecb_encrypt((des_cblock *)clear, (des_cblock *)cipher, key_schedule, 1);
+
+#if 0
+ CHAPDEBUG((LOG_INFO, "DesEncrypt: 8 octet output: %02X%02X%02X%02X%02X%02X%02X%02X",
+ cipher[0], cipher[1], cipher[2], cipher[3], cipher[4], cipher[5], cipher[6], cipher[7]));
+#endif
+}
+
+
+static u_char Get7Bits(input, startBit)
+ u_char *input;
+ int startBit;
+{
+ register unsigned int word;
+
+ word = (unsigned)input[startBit / 8] << 8;
+ word |= (unsigned)input[startBit / 8 + 1];
+
+ word >>= 15 - (startBit % 8 + 7);
+
+ return word & 0xFE;
+}
+
+
+static void MakeKey(key, des_key)
+ u_char *key; /* IN 56 bit DES key missing parity bits */
+ u_char *des_key; /* OUT 64 bit DES key with parity bits added */
+{
+ des_key[0] = Get7Bits(key, 0);
+ des_key[1] = Get7Bits(key, 7);
+ des_key[2] = Get7Bits(key, 14);
+ des_key[3] = Get7Bits(key, 21);
+ des_key[4] = Get7Bits(key, 28);
+ des_key[5] = Get7Bits(key, 35);
+ des_key[6] = Get7Bits(key, 42);
+ des_key[7] = Get7Bits(key, 49);
+
+ des_set_odd_parity((des_cblock *)des_key);
+
+#if 0
+ CHAPDEBUG((LOG_INFO, "MakeKey: 56-bit input : %02X%02X%02X%02X%02X%02X%02X",
+ key[0], key[1], key[2], key[3], key[4], key[5], key[6]));
+ CHAPDEBUG((LOG_INFO, "MakeKey: 64-bit output: %02X%02X%02X%02X%02X%02X%02X%02X",
+ des_key[0], des_key[1], des_key[2], des_key[3], des_key[4], des_key[5], des_key[6], des_key[7]));
+#endif
+}
+
+#endif /* CHAPMS */
+
+
+void
+ChapMS(cstate, rchallenge, rchallenge_len, secret, secret_len)
+ chap_state *cstate;
+ char *rchallenge;
+ int rchallenge_len;
+ char *secret;
+ int secret_len;
+{
+#ifdef CHAPMS
+ int i;
+ MDstruct md4Context;
+ MS_ChapResponse response;
+ u_char unicodePassword[MAX_NT_PASSWORD * 2];
+
+#if 0
+ CHAPDEBUG((LOG_INFO, "ChapMS: secret is '%.*s'", secret_len, secret));
+#endif
+
+ BZERO(&response, sizeof(response));
+
+ /* Initialize the Unicode version of the secret (== password). */
+ /* This implicitly supports 8-bit ISO8859/1 characters. */
+ BZERO(unicodePassword, sizeof(unicodePassword));
+ for (i = 0; i < secret_len; i++)
+ unicodePassword[i * 2] = (u_char)secret[i];
+
+ MDbegin(&md4Context);
+ MDupdate(&md4Context, unicodePassword, secret_len * 2 * 8); /* Unicode is 2 bytes/char, *8 for bit count */
+ MDupdate(&md4Context, NULL, 0); /* Tell MD4 we're done */
+
+ ChallengeResponse(rchallenge, (char *)md4Context.buffer, response.NTResp);
+
+ response.UseNT = 1;
+
+ BCOPY(&response, cstate->response, MS_CHAP_RESPONSE_LEN);
+ cstate->resp_length = MS_CHAP_RESPONSE_LEN;
+#endif /* CHAPMS */
+}