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+/*
+ * $Id: md5_crypt.c,v 1.1 2002-05-11 14:42:35 cpbotha Exp $
+ *
+ * ----------------------------------------------------------------------------
+ * "THE BEER-WARE LICENSE" (Revision 42):
+ * <phk@login.dknet.dk> wrote this file. As long as you retain this notice you
+ * can do whatever you want with this stuff. If we meet some day, and you think
+ * this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
+ * ----------------------------------------------------------------------------
+ *
+ * Origin: Id: crypt.c,v 1.3 1995/05/30 05:42:22 rgrimes Exp
+ *
+ */
+
+#include <string.h>
+#include "md5.h"
+
+static unsigned char itoa64[] = /* 0 ... 63 => ascii - 64 */
+"./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
+
+static void to64(char *s, unsigned long v, int n)
+{
+ while (--n >= 0) {
+ *s++ = itoa64[v & 0x3f];
+ v >>= 6;
+ }
+}
+
+/*
+ * UNIX password
+ *
+ * Use MD5 for what it is best at...
+ */
+
+char *MD5Name(crypt_md5)(const char *pw, const char *salt)
+{
+ const char *magic = "$1$";
+ /* This string is magic for this algorithm. Having
+ * it this way, we can get get better later on */
+ static char passwd[120], *p;
+ static const char *sp, *ep;
+ unsigned char final[16];
+ int sl, pl, i, j;
+ MD5_CTX ctx, ctx1;
+ unsigned long l;
+
+ /* Refine the Salt first */
+ sp = salt;
+
+ /* If it starts with the magic string, then skip that */
+ if (!strncmp(sp, magic, strlen(magic)))
+ sp += strlen(magic);
+
+ /* It stops at the first '$', max 8 chars */
+ for (ep = sp; *ep && *ep != '$' && ep < (sp + 8); ep++)
+ continue;
+
+ /* get the length of the true salt */
+ sl = ep - sp;
+
+ MD5Name(MD5Init)(&ctx);
+
+ /* The password first, since that is what is most unknown */
+ MD5Name(MD5Update)(&ctx,(unsigned const char *)pw,strlen(pw));
+
+ /* Then our magic string */
+ MD5Name(MD5Update)(&ctx,(unsigned const char *)magic,strlen(magic));
+
+ /* Then the raw salt */
+ MD5Name(MD5Update)(&ctx,(unsigned const char *)sp,sl);
+
+ /* Then just as many characters of the MD5(pw,salt,pw) */
+ MD5Name(MD5Init)(&ctx1);
+ MD5Name(MD5Update)(&ctx1,(unsigned const char *)pw,strlen(pw));
+ MD5Name(MD5Update)(&ctx1,(unsigned const char *)sp,sl);
+ MD5Name(MD5Update)(&ctx1,(unsigned const char *)pw,strlen(pw));
+ MD5Name(MD5Final)(final,&ctx1);
+ for (pl = strlen(pw); pl > 0; pl -= 16)
+ MD5Name(MD5Update)(&ctx,(unsigned const char *)final,pl>16 ? 16 : pl);
+
+ /* Don't leave anything around in vm they could use. */
+ memset(final, 0, sizeof final);
+
+ /* Then something really weird... */
+ for (j = 0, i = strlen(pw); i; i >>= 1)
+ if (i & 1)
+ MD5Name(MD5Update)(&ctx, (unsigned const char *)final+j, 1);
+ else
+ MD5Name(MD5Update)(&ctx, (unsigned const char *)pw+j, 1);
+
+ /* Now make the output string */
+ strcpy(passwd, magic);
+ strncat(passwd, sp, sl);
+ strcat(passwd, "$");
+
+ MD5Name(MD5Final)(final,&ctx);
+
+ /*
+ * and now, just to make sure things don't run too fast
+ * On a 60 Mhz Pentium this takes 34 msec, so you would
+ * need 30 seconds to build a 1000 entry dictionary...
+ */
+ for (i = 0; i < 1000; i++) {
+ MD5Name(MD5Init)(&ctx1);
+ if (i & 1)
+ MD5Name(MD5Update)(&ctx1,(unsigned const char *)pw,strlen(pw));
+ else
+ MD5Name(MD5Update)(&ctx1,(unsigned const char *)final,16);
+
+ if (i % 3)
+ MD5Name(MD5Update)(&ctx1,(unsigned const char *)sp,sl);
+
+ if (i % 7)
+ MD5Name(MD5Update)(&ctx1,(unsigned const char *)pw,strlen(pw));
+
+ if (i & 1)
+ MD5Name(MD5Update)(&ctx1,(unsigned const char *)final,16);
+ else
+ MD5Name(MD5Update)(&ctx1,(unsigned const char *)pw,strlen(pw));
+ MD5Name(MD5Final)(final,&ctx1);
+ }
+
+ p = passwd + strlen(passwd);
+
+ l = (final[0] << 16) | (final[6] << 8) | final[12];
+ to64(p, l, 4);
+ p += 4;
+ l = (final[1] << 16) | (final[7] << 8) | final[13];
+ to64(p, l, 4);
+ p += 4;
+ l = (final[2] << 16) | (final[8] << 8) | final[14];
+ to64(p, l, 4);
+ p += 4;
+ l = (final[3] << 16) | (final[9] << 8) | final[15];
+ to64(p, l, 4);
+ p += 4;
+ l = (final[4] << 16) | (final[10] << 8) | final[5];
+ to64(p, l, 4);
+ p += 4;
+ l = final[11];
+ to64(p, l, 2);
+ p += 2;
+ *p = '\0';
+
+ /* Don't leave anything around in vm they could use. */
+ memset(final, 0, sizeof final);
+
+ return passwd;
+}