libs/libhmac/hmac.c

   1 /*
   2 ** Copyright 1998 - 1999 Double Precision, Inc.
   3 ** See COPYING for distribution information.
   4 */
   5
   6 #if     HAVE_CONFIG_H
   7 #include        "config.h"
   8 #endif
   9
  10 #include        "hmac.h"
  11
  12
  13 struct hmac_hashinfo *hmac_list[]= {HMAC_LIST};
  14
  15 struct hhki {
  16         const struct hmac_hashinfo *hh;
  17         const char *k;
  18         size_t kl;
  19         unsigned char *kxopad;
  20         unsigned char *kxipad;
  21
  22         void *context;
  23         } ;
  24
  25 static void dohashkey(unsigned char *, void *);
  26 static void docalcc(void *, void *);
  27
  28 void hmac_hashkey(const struct hmac_hashinfo *hh, const char *k,
  29         size_t kl, unsigned char *kxopad, unsigned char *kxipad)
  30 {
  31 struct hhki i;
  32
  33         i.hh=hh;
  34         i.k=k;
  35         i.kl=kl;
  36         i.kxopad=kxopad;
  37         i.kxipad=kxipad;
  38
  39         (*hh->hh_allocacontext)( docalcc, (void *)&i );
  40 }
  41
  42 static void dokeycalc(struct hhki *);
  43
  44 static void docalcc(void *c, void *v)
  45 {
  46 struct hhki *i=(struct hhki *)v;
  47
  48         i->context=c;
  49
  50         if (i->kl > i->hh->hh_B)
  51                 (*i->hh->hh_allocaval)(dohashkey, (void *)i);
  52         else
  53                 dokeycalc( i );
  54 }
  55
  56 static void dohashkey(unsigned char *keybuf, void *v)
  57 {
  58 struct hhki *i=(struct hhki *)v;
  59
  60         (*i->hh->hh_init)(i->context);
  61         (*i->hh->hh_hash)(i->context, i->k, i->kl);
  62         (*i->hh->hh_endhash)(i->context, i->kl);
  63         (*i->hh->hh_getdigest)(i->context, keybuf);
  64         i->k=(char *)keybuf;
  65         i->kl=i->hh->hh_L;
  66         dokeycalc(i);
  67 }
  68
  69 static void dokeycalc(struct hhki *i)
  70 {
  71 char    buf[64];        /* Random guess :-) */
  72 unsigned n;
  73 unsigned l;
  74
  75         (*i->hh->hh_init)(i->context);
  76         n=0;
  77         for (l=0; l<i->hh->hh_B; l++)
  78         {
  79                 buf[n] = ( l < i->kl ? i->k[l]:0) ^ 0x5C;
  80                 if ( ++n >= sizeof(buf))
  81                 {
  82                         (*i->hh->hh_hash)(i->context, buf, sizeof(buf));
  83                         n=0;
  84                 }
  85         }
  86         if (n)
  87                 (*i->hh->hh_hash)(i->context, buf, n);
  88         (*i->hh->hh_getdigest)(i->context, i->kxopad);
  89
  90         (*i->hh->hh_init)(i->context);
  91         n=0;
  92         for (l=0; l<i->hh->hh_B; l++)
  93         {
  94                 buf[n] = ( l < i->kl ? i->k[l]:0) ^ 0x36;
  95                 if ( ++n >= sizeof(buf))
  96                 {
  97                         (*i->hh->hh_hash)(i->context, buf, sizeof(buf));
  98                         n=0;
  99                 }
 100         }
 101         if (n)
 102                 (*i->hh->hh_hash)(i->context, buf, n);
 103         (*i->hh->hh_getdigest)(i->context, i->kxipad);
 104 }
 105
 106 struct hhko {
 107         const struct hmac_hashinfo *hh;
 108         const char *t;
 109         size_t tl;
 110         const unsigned char *kxopad;
 111         const unsigned char *kxipad;
 112         unsigned char *hash;
 113         } ;
 114
 115 static void docalch(void *, void *);
 116
 117 void hmac_hashtext (
 118         const struct hmac_hashinfo *hh,
 119         const char *t,
 120         size_t tl,
 121         const unsigned char *kxopad,
 122         const unsigned char *kxipad,
 123         unsigned char *hash)
 124 {
 125 struct hhko o;
 126
 127         o.hh=hh;
 128         o.t=t;
 129         o.tl=tl;
 130         o.kxopad=kxopad;
 131         o.kxipad=kxipad;
 132         o.hash=hash;
 133
 134         (*hh->hh_allocacontext)( docalch, (void *)&o );
 135 }
 136
 137 static void docalch(void *c, void *v)
 138 {
 139 struct hhko *o=(struct hhko *)v;
 140
 141         (o->hh->hh_setdigest)(c, o->kxipad);
 142         (o->hh->hh_hash)(c, o->t, o->tl);
 143         (o->hh->hh_endhash)(c, o->tl+o->hh->hh_B);
 144         (o->hh->hh_getdigest)(c, o->hash);
 145
 146         (o->hh->hh_setdigest)(c, o->kxopad);
 147         (o->hh->hh_hash)(c, o->hash, o->hh->hh_L);
 148         (o->hh->hh_endhash)(c, o->hh->hh_L + o->hh->hh_B);
 149         (o->hh->hh_getdigest)(c, o->hash);
 150 }