153 lines
4.1 KiB
C
153 lines
4.1 KiB
C
/*
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* $Id$
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*
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* ----------------------------------------------------------------------------
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* "THE BEER-WARE LICENSE" (Revision 42):
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* <phk@login.dknet.dk> wrote this file. As long as you retain this notice you
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* can do whatever you want with this stuff. If we meet some day, and you think
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* this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
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* ----------------------------------------------------------------------------
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*
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* Origin: Id: crypt.c,v 1.3 1995/05/30 05:42:22 rgrimes Exp
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*
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*/
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#include "pam_inline.h"
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#include <string.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include "md5.h"
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static const unsigned char itoa64[] = /* 0 ... 63 => ascii - 64 */
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"./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
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static void to64(char *s, unsigned long v, int n)
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{
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while (--n >= 0) {
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*s++ = itoa64[v & 0x3f];
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v >>= 6;
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}
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}
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/*
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* UNIX password
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*
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* Use MD5 for what it is best at...
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*/
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char *MD5Name(crypt_md5)(const char *pw, const char *salt)
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{
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const char *magic = "$1$";
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/* This string is magic for this algorithm. Having
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* it this way, we can get better later on */
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char *passwd, *p;
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const char *sp, *ep;
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char buf[23];
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unsigned char final[16];
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int sl, pl, i, j;
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MD5_CTX ctx, ctx1;
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unsigned long l;
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/* Refine the Salt first */
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sp = salt;
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/* If it starts with the magic string, then skip that */
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if ((ep = pam_str_skip_prefix_len(sp, magic, strlen(magic))) != NULL)
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sp = ep;
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/* It stops at the first '$', max 8 chars */
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for (ep = sp; *ep && *ep != '$' && ep < (sp + 8); ep++)
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continue;
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/* get the length of the true salt */
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sl = ep - sp;
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MD5Name(MD5Init)(&ctx);
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/* The password first, since that is what is most unknown */
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MD5Name(MD5Update)(&ctx,(unsigned const char *)pw,strlen(pw));
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/* Then our magic string */
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MD5Name(MD5Update)(&ctx,(unsigned const char *)magic,strlen(magic));
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/* Then the raw salt */
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MD5Name(MD5Update)(&ctx,(unsigned const char *)sp,sl);
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/* Then just as many characters of the MD5(pw,salt,pw) */
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MD5Name(MD5Init)(&ctx1);
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MD5Name(MD5Update)(&ctx1,(unsigned const char *)pw,strlen(pw));
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MD5Name(MD5Update)(&ctx1,(unsigned const char *)sp,sl);
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MD5Name(MD5Update)(&ctx1,(unsigned const char *)pw,strlen(pw));
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MD5Name(MD5Final)(final,&ctx1);
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for (pl = strlen(pw); pl > 0; pl -= 16)
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MD5Name(MD5Update)(&ctx,(unsigned const char *)final,pl>16 ? 16 : pl);
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/* Don't leave anything around in vm they could use. */
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pam_overwrite_array(final);
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/* Then something really weird... */
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for (j = 0, i = strlen(pw); i; i >>= 1)
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if (i & 1)
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MD5Name(MD5Update)(&ctx, (unsigned const char *)final+j, 1);
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else
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MD5Name(MD5Update)(&ctx, (unsigned const char *)pw+j, 1);
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MD5Name(MD5Final)(final,&ctx);
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/*
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* and now, just to make sure things don't run too fast
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* On a 60 Mhz Pentium this takes 34 msec, so you would
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* need 30 seconds to build a 1000 entry dictionary...
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*/
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for (i = 0; i < 1000; i++) {
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MD5Name(MD5Init)(&ctx1);
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if (i & 1)
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MD5Name(MD5Update)(&ctx1,(unsigned const char *)pw,strlen(pw));
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else
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MD5Name(MD5Update)(&ctx1,(unsigned const char *)final,16);
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if (i % 3)
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MD5Name(MD5Update)(&ctx1,(unsigned const char *)sp,sl);
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if (i % 7)
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MD5Name(MD5Update)(&ctx1,(unsigned const char *)pw,strlen(pw));
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if (i & 1)
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MD5Name(MD5Update)(&ctx1,(unsigned const char *)final,16);
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else
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MD5Name(MD5Update)(&ctx1,(unsigned const char *)pw,strlen(pw));
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MD5Name(MD5Final)(final,&ctx1);
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}
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p = buf;
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l = (final[0] << 16) | (final[6] << 8) | final[12];
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to64(p, l, 4);
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p += 4;
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l = (final[1] << 16) | (final[7] << 8) | final[13];
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to64(p, l, 4);
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p += 4;
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l = (final[2] << 16) | (final[8] << 8) | final[14];
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to64(p, l, 4);
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p += 4;
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l = (final[3] << 16) | (final[9] << 8) | final[15];
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to64(p, l, 4);
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p += 4;
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l = (final[4] << 16) | (final[10] << 8) | final[5];
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to64(p, l, 4);
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p += 4;
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l = final[11];
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to64(p, l, 2);
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p += 2;
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*p = '\0';
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/* Now make the output string */
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if (asprintf(&passwd, "%s%.*s$%s", magic, sl, sp, buf) < 0)
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passwd = NULL;
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/* Don't leave anything around in vm they could use. */
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pam_overwrite_array(buf);
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pam_overwrite_array(final);
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return passwd;
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}
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