+/*
+ * pppcrypt.c - PPP/DES linkage for MS-CHAP and EAP SRP-SHA1
+ *
+ * Extracted from chap_ms.c by James Carlson.
+ *
+ * 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.
+ */
+
+#include <errno.h>
+#include "pppd.h"
+#include "pppcrypt.h"
+
+static u_char
+Get7Bits(input, startBit)
+u_char *input;
+int startBit;
+{
+ 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);
+
+#ifndef USE_CRYPT
+ des_set_odd_parity((des_cblock *)des_key);
+#endif
+}
+
+#ifdef USE_CRYPT
+/*
+ * in == 8-byte string (expanded version of the 56-bit key)
+ * out == 64-byte string where each byte is either 1 or 0
+ * Note that the low-order "bit" is always ignored by by setkey()
+ */
+static void
+Expand(in, out)
+u_char *in;
+u_char *out;
+{
+ int j, c;
+ int i;
+
+ for (i = 0; i < 64; in++){
+ c = *in;
+ for (j = 7; j >= 0; j--)
+ *out++ = (c >> j) & 01;
+ i += 8;
+ }
+}
+
+/* The inverse of Expand
+ */
+static void
+Collapse(in, out)
+u_char *in;
+u_char *out;
+{
+ int j;
+ int i;
+ unsigned int c;
+
+ for (i = 0; i < 64; i += 8, out++) {
+ c = 0;
+ for (j = 7; j >= 0; j--, in++)
+ c |= *in << j;
+ *out = c & 0xff;
+ }
+}
+
+bool
+DesSetkey(key)
+u_char *key;
+{
+ u_char des_key[8];
+ u_char crypt_key[66];
+
+ MakeKey(key, des_key);
+ Expand(des_key, crypt_key);
+ errno = 0;
+ setkey((const char *)crypt_key);
+ if (errno != 0)
+ return (0);
+ return (1);
+}
+
+bool
+DesEncrypt(clear, cipher)
+u_char *clear; /* IN 8 octets */
+u_char *cipher; /* OUT 8 octets */
+{
+ u_char des_input[66];
+
+ Expand(clear, des_input);
+ errno = 0;
+ encrypt((char *)des_input, 0);
+ if (errno != 0)
+ return (0);
+ Collapse(des_input, cipher);
+ return (1);
+}
+
+bool
+DesDecrypt(cipher, clear)
+u_char *cipher; /* IN 8 octets */
+u_char *clear; /* OUT 8 octets */
+{
+ u_char des_input[66];
+
+ Expand(cipher, des_input);
+ errno = 0;
+ encrypt((char *)des_input, 1);
+ if (errno != 0)
+ return (0);
+ Collapse(des_input, clear);
+ return (1);
+}
+
+#else /* USE_CRYPT */
+static des_key_schedule key_schedule;
+
+bool
+DesSetkey(key)
+u_char *key;
+{
+ des_cblock des_key;
+ MakeKey(key, des_key);
+ des_set_key(&des_key, key_schedule);
+ return (1);
+}
+
+bool
+DesEncrypt(clear, key, cipher)
+u_char *clear; /* IN 8 octets */
+u_char *cipher; /* OUT 8 octets */
+{
+ des_ecb_encrypt((des_cblock *)clear, (des_cblock *)cipher,
+ key_schedule, 1);
+ return (1);
+}
+
+bool
+DesDecrypt(cipher, clear)
+u_char *cipher; /* IN 8 octets */
+u_char *clear; /* OUT 8 octets */
+{
+ des_ecb_encrypt((des_cblock *)cipher, (des_cblock *)clear,
+ key_schedule, 0);
+ return (1);
+}
+
+#endif /* USE_CRYPT */