git.distorted.org.uk Git - u/mdw/catacomb/blob - key-pack.c

   1 /* -*-c-*-
   2  *
   3  * $Id: key-pack.c,v 1.1 2000/06/17 10:42:41 mdw Exp $
   4  *
   5  * Packing and unpacking key data
   6  *
   7  * (c) 1999 Straylight/Edgeware
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of Catacomb.
  13  *
  14  * Catacomb is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU Library General Public License as
  16  * published by the Free Software Foundation; either version 2 of the
  17  * License, or (at your option) any later version.
  18  *
  19  * Catacomb is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU Library General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU Library General Public
  25  * License along with Catacomb; if not, write to the Free
  26  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  27  * MA 02111-1307, USA.
  28  */
  29
  30 /*----- Revision history --------------------------------------------------*
  31  *
  32  * $Log: key-pack.c,v $
  33  * Revision 1.1  2000/06/17 10:42:41  mdw
  34  * Packing and unpacking structured keys.
  35  *
  36  */
  37
  38 /*----- Header files ------------------------------------------------------*/
  39
  40 #include <mLib/dstr.h>
  41
  42 #include "key.h"
  43 #include "key-data.h"
  44
  45 /*----- Generic packing and unpacking -------------------------------------*/
  46
  47 /* --- @key_pack@ --- *
  48  *
  49  * Arguments:   @key_packdef *kp@ = pointer to packing structure
  50  *              @key_data *kd@ = pointer to destination key data
  51  *              @dstr *d@ = pointer to tag string for the key data
  52  *
  53  * Returns:     Error code, or zero.
  54  *
  55  * Use:         Packs a key from a data structure.
  56  */
  57
  58 int key_pack(key_packdef *kp, key_data *kd, dstr *d)
  59 {
  60   switch (kp->kd.e & KF_ENCMASK) {
  61
  62     /* --- Binary and integer keys are easy --- */
  63
  64     case KENC_BINARY:
  65       kd->u.k = *(key_bin *)kp->p;
  66       return (0);
  67     case KENC_MP:
  68       kd->u.m = *(mp **)kp->p;
  69       return (0);
  70
  71     /* --- Encrypted keys are a little tricky --- *
  72      *
  73      * This works rather differently to unpacking.
  74      */
  75
  76     case KENC_ENCRYPT: {
  77       key_data kkd;
  78       int err = key_pack(kp->p, &kkd, d);
  79       if (!err) {
  80         if (key_plock(d->buf, &kkd, kd))
  81           err = KERR_BADPASS;
  82         key_destroy(&kkd);
  83       }
  84       return (err);
  85     }
  86
  87     /* --- Structured keys, as ever, are a nuisance --- */
  88
  89     case KENC_STRUCT: {
  90       int err;
  91       key_packstruct *p;
  92       size_t l = d->len;
  93
  94       key_structure(kd);
  95       DPUTC(d, '.');
  96       for (p = kp->p; p->name; p++) {
  97         key_data *kkd;
  98         d->len = l + 1;
  99         DPUTS(d, p->name);
 100         kkd = key_structcreate(kd, p->name);
 101         if ((err = key_pack(&p->kp, kkd, d)) != 0) {
 102           key_destroy(kd);
 103           return (err);
 104         }
 105       }
 106       d->len = l;
 107       d->buf[l] = 0;
 108       return (0);
 109     }
 110   }
 111
 112   return (KERR_BADTYPE);
 113 }
 114
 115 /* --- @key_unpack@ --- *
 116  *
 117  * Arguments:   @key_packdef *kp@ = pointer to packing structure
 118  *              @key_data *kd@ = pointer to source key data
 119  *              @dstr *d@ = pointer to tag string for the key data
 120  *
 121  * Returns:     Error code, or zero.
 122  *
 123  * Use:         Unpacks a key into an appropriate data structure.
 124  */
 125
 126 int key_unpack(key_packdef *kp, key_data *kd, dstr *d)
 127 {
 128   unsigned e = kp->kd.e & KF_ENCMASK;
 129   int err;
 130
 131   /* --- Decrypt the encrypted key --- */
 132
 133   while ((kd->e & KF_ENCMASK) == KENC_ENCRYPT) {
 134     if (key_punlock(d->buf, kd, &kp->kd)) {
 135       err = KERR_BADPASS;
 136       goto fail;
 137     }
 138     kd = &kp->kd;
 139     kd->e |= KF_TEMP;
 140   }
 141
 142   /* --- Ensure that the key has the right type --- */
 143
 144   if ((kd->e & KF_ENCMASK) != e) {
 145     err = KERR_BADTYPE;
 146     goto fail;
 147   }
 148
 149   /* --- Unpack the key --- *
 150    *
 151    * Only three possibilities left now.
 152    */
 153
 154   switch (e) {
 155
 156     /* --- Binary and integer keys are easy --- */
 157
 158     case KENC_BINARY:
 159       *(key_bin *)kp->p = kd->u.k;
 160       break;
 161     case KENC_MP:
 162       *(mp **)kp->p = kd->u.m;
 163       break;
 164
 165     /* --- Structured keys take a little care --- */
 166
 167     case KENC_STRUCT: {
 168       key_packstruct *p, *q;
 169       size_t l = d->len;
 170
 171       /* --- Iterate over the requested subparts --- */
 172
 173       DPUTC(d, '.');
 174       for (p = kp->p; p->name; p++) {
 175         key_data *kkd;
 176
 177         /* --- Build the name --- */
 178
 179         d->len = l + 1;
 180         DPUTS(d, p->name);
 181
 182         /* --- Find and unpack the subkey --- */
 183
 184         if ((kkd = key_structfind(kd, p->name)) == 0) {
 185           if (!(p->kp.kd.e & KF_OPT)) {
 186             err = KERR_NOTFOUND;
 187             goto tidy;
 188           }
 189         } else if ((err = key_unpack(&p->kp, kkd, d)) != 0) {
 190           p++;
 191           goto tidy;
 192         }
 193       }
 194
 195       /* --- Done --- */
 196
 197       d->len = l;
 198       d->buf[l] = 0;
 199       break;
 200
 201       /* --- Tidy up if something went wrong --- */
 202
 203     tidy:
 204       for (q = kp->p; q < p; q++)
 205         key_unpackdone(&q->kp);
 206       goto fail;
 207     }
 208   }
 209
 210   return (0);
 211
 212   /* --- Something went wrong --- */
 213
 214 fail:
 215   if (kd == &kp->kd)
 216     key_destroy(kd);
 217   return (err);
 218 }
 219
 220 /* --- @key_unpackdone@ --- *
 221  *
 222  * Arguments:   @key_packdef *kp@ = pointer to packing definition
 223  *
 224  * Returns:     ---
 225  *
 226  * Use:         Frees the key components contained within a packing
 227  *              definition, created during key unpacking.
 228  */
 229
 230 void key_unpackdone(key_packdef *kp)
 231 {
 232   if (kp->kd.e & KF_TEMP)
 233     key_destroy(&kp->kd);
 234   if ((kp->kd.e & KF_ENCMASK) == KENC_STRUCT) {
 235     key_packstruct *p;
 236     for (p = kp->p; p->name; p++)
 237       key_unpackdone(&p->kp);
 238   }
 239 }
 240
 241 /*----- That's all, folks -------------------------------------------------*/