digest_md5.c

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/*
 * digest_md5.c taken for Manvendra's Indimail
 * adjusted for use with s/qmail by permission
 *
 * Note: DIGEST-MD5 appeared in RFC 2831 and is historic now (RFC 6331).
 *       Though it originates from M$ and the year 2000, it already 
 *       looks like an AI slop, pretending to be better than CRAM-MD5
 *
 */
#include "global.h"
#include "md5.h"
#include "str.h"
#include "stralloc.h"
 
static char hextab[] = "0123456789abcdef";
 
int digest_md5(unsigned char *digestmd5,stralloc *user,stralloc *realm,stralloc *pass,
               char *authzid,stralloc *nonce,stralloc *digesturi, 
               char *cnonce,const char *nc,const char *qop)
{
  int j;
  unsigned char digest[20], ea1[33], ea2[33];
  MD5_CTX md5;
 
  if (user->len < 2) return 0;
  if (pass->len < 2) return 0;
  if (realm->len < 2) return 0;
  if (nonce->len < 2) return 0;
  if (digesturi->len < 2) return 0;
  if (!cnonce || !nc || !qop) return 0;
 
  MD5Init(&md5);
  MD5Update(&md5,(unsigned char *)user->s,user->len);
  MD5Update(&md5,(unsigned char *)":",1);
  MD5Update(&md5,(unsigned char *)realm->s,realm->len);
  MD5Update(&md5,(unsigned char *)":",1);
  MD5Update(&md5,(unsigned char *)pass->s,pass->len);
  MD5Final(digest,&md5);
 
  MD5Init(&md5);
  MD5Update(&md5,digest,16);                     /* md5(user+realm+pass) */
  MD5Update(&md5,(unsigned char *)":",1);
  MD5Update(&md5,(unsigned char *)nonce->s,nonce->len);
  MD5Update(&md5,(unsigned char *)":",1);
  MD5Update(&md5,(unsigned char *)cnonce,32);
  if (authzid && *authzid) {                     /* warning: not tested with authzid! */
    MD5Update(&md5,(unsigned char *)":",1);
    MD5Update(&md5,(unsigned char *)authzid,str_len(authzid));
  }
  MD5Final(digest,&md5);
  for (j = 0; j < 16; j++) {
    ea1[j]     = hextab[digest[j] / 16]; 
    ea1[j + 1] = hextab[digest[j] % 16]; 
  }
  ea1[32] = 0;                                   /* ea1 = ready */
 
  MD5Init(&md5);
  MD5Update(&md5,(unsigned char *)"AUTHENTICATE:",13);
  MD5Update(&md5,(unsigned char *)digesturi->s,digesturi->len);
  if (str_len(qop) > 4)                          /* for auth-* type */
    MD5Update(&md5,(unsigned char *)":00000000000000000000000000000000",32);
  MD5Final(digest,&md5);
 
  for (j = 0; j < 16; j++) {
    ea2[j]     = hextab[digest[j] / 16]; 
    ea2[j + 1] = hextab[digest[j] % 16]; 
  }
  ea2[32] = 0;                                   /* ea2 = ready */
 
  /* digestmd5 = hex(a1) + nonce + nc + cnonce + qop + hex(a2) */
 
  MD5Init(&md5);
  MD5Update(&md5,ea1,32);
  MD5Update(&md5,(unsigned char *)":",1);
  MD5Update(&md5,(unsigned char *)nonce->s,nonce->len);
  MD5Update(&md5,(unsigned char *)":",1);
  MD5Update(&md5,(unsigned char *)nc,str_len(nc));
  MD5Update(&md5,(unsigned char *) ":",1);
  MD5Update(&md5,(unsigned char *)cnonce, 32);
  MD5Update(&md5,(unsigned char *) ":",1);
  MD5Update(&md5,(unsigned char *)qop, str_len(qop));
  MD5Update(&md5,(unsigned char *)":",1);
  MD5Update(&md5,ea2, 32);
  MD5Final(digest,&md5);
 
  for (j = 0; j < 16; j++) {
    digestmd5[j]     = hextab[digest[j] / 16];
    digestmd5[j + 1] = hextab[digest[j] % 16];
  }
  digestmd5[32] = 0;                             /* done */
 
  return 1;
}