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

   1 /* -*-c-*-
   2  *
   3  * $Id$
   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 /*----- Header files ------------------------------------------------------*/
  31
  32 #include <mLib/dstr.h>
  33
  34 #include "key-data.h"
  35
  36 /*----- Generic packing and unpacking -------------------------------------*/
  37
  38 /* --- @key_pack@ --- *
  39  *
  40  * Arguments:   @key_packdef *kp@ = pointer to packing structure
  41  *              @key_data **kd@ = where to put the key data pointer
  42  *              @dstr *d@ = pointer to tag string for the key data
  43  *
  44  * Returns:     Error code, or zero.
  45  *
  46  * Use:         Packs a key from a data structure.
  47  */
  48
  49 int key_pack(key_packdef *kp, key_data **kd, dstr *d)
  50 {
  51   switch (kp->e & KF_ENCMASK) {
  52
  53     /* --- Binary and integer keys are easy --- */
  54
  55     case KENC_BINARY: {
  56       key_bin *b = kp->p;
  57       *kd = key_newbinary(kp->e, b->k, b->sz);
  58       return (0);
  59     }
  60     case KENC_MP:
  61       *kd = key_newmp(kp->e, *(mp **)kp->p);
  62       return (0);
  63     case KENC_STRING:
  64       *kd = key_newstring(kp->e, *(char **)kp->p);
  65       return (0);
  66     case KENC_EC:
  67       *kd = key_newec(kp->e, (ec *)kp->p);
  68       return (0);
  69
  70     /* --- Encrypted keys are a little tricky --- *
  71      *
  72      * This works rather differently to unpacking.
  73      */
  74
  75     case KENC_ENCRYPT: {
  76       key_data *kkd;
  77       int err = key_pack(kp->p, &kkd, d);
  78       if (!err) {
  79         err = key_plock(kd, kkd, d->buf);
  80         key_drop(kkd);
  81       }
  82       return (err);
  83     }
  84
  85     /* --- Structured keys, as ever, are a nuisance --- */
  86
  87     case KENC_STRUCT: {
  88       int err;
  89       key_packstruct *p;
  90       size_t l = d->len;
  91
  92       *kd = key_newstruct();
  93       DPUTC(d, '.');
  94       for (p = kp->p; p->name; p++) {
  95         key_data *kkd;
  96         d->len = l + 1;
  97         DPUTS(d, p->name);
  98         if ((err = key_pack(&p->kp, &kkd, d)) != 0) {
  99           key_drop(*kd);
 100           return (err);
 101         }
 102         key_structsteal(*kd, p->name, kkd);
 103       }
 104       d->len = l;
 105       d->buf[l] = 0;
 106       return (0);
 107     }
 108     default:
 109       abort();
 110   }
 111 }
 112
 113 /* --- @key_unpack@ --- *
 114  *
 115  * Arguments:   @key_packdef *kp@ = pointer to packing structure
 116  *              @key_data *kd@ = pointer to source key data
 117  *              @dstr *d@ = pointer to tag string for the key data
 118  *
 119  * Returns:     Error code, or zero.
 120  *
 121  * Use:         Unpacks a key into an appropriate data structure.
 122  */
 123
 124 int key_unpack(key_packdef *kp, key_data *kd, dstr *d)
 125 {
 126   unsigned e = kp->e & KF_ENCMASK;
 127   int err;
 128
 129   /* --- Decrypt the encrypted key --- */
 130
 131   if ((kd->e & KF_ENCMASK) == KENC_ENCRYPT) {
 132     if ((err = key_punlock(&kp->kd, kd, d->buf)) != 0)
 133       goto fail;
 134     kd = kp->kd;
 135   }
 136
 137   /* --- Ensure that the key has the right type --- */
 138
 139   if ((kd->e & KF_ENCMASK) != e) {
 140     err = KERR_WRONGTYPE;
 141     goto fail;
 142   }
 143
 144   /* --- Unpack the key --- *
 145    *
 146    * Only three possibilities left now.
 147    */
 148
 149   switch (e) {
 150
 151     /* --- Binary and integer keys are easy --- */
 152
 153     case KENC_BINARY:
 154       *(key_bin *)kp->p = kd->u.k;
 155       break;
 156     case KENC_MP:
 157       *(mp **)kp->p = kd->u.m;
 158       break;
 159     case KENC_STRING:
 160       *(char **)kp->p = kd->u.p;
 161       break;
 162     case KENC_EC:
 163       *(ec *)kp->p = kd->u.e;
 164       break;
 165
 166     /* --- Structured keys take a little care --- */
 167
 168     case KENC_STRUCT: {
 169       key_packstruct *p, *q;
 170       size_t l = d->len;
 171
 172       /* --- Iterate over the requested subparts --- */
 173
 174       DPUTC(d, '.');
 175       for (p = kp->p; p->name; p++) {
 176         key_data *kkd;
 177
 178         /* --- Build the name --- */
 179
 180         d->len = l + 1;
 181         DPUTS(d, p->name);
 182
 183         /* --- Find and unpack the subkey --- */
 184
 185         if ((kkd = key_structfind(kd, p->name)) == 0) {
 186           if (!(p->kp.e & KF_OPT)) {
 187             err = KERR_NOTFOUND;
 188             goto tidy;
 189           }
 190         } else if ((err = key_unpack(&p->kp, kkd, d)) != 0) {
 191           p++;
 192           goto tidy;
 193         }
 194       }
 195
 196       /* --- Done --- */
 197
 198       d->len = l;
 199       d->buf[l] = 0;
 200       break;
 201
 202       /* --- Tidy up if something went wrong --- */
 203
 204     tidy:
 205       for (q = kp->p; q < p; q++)
 206         key_unpackdone(&q->kp);
 207       goto fail;
 208     }
 209
 210     default:
 211       abort();
 212   }
 213
 214   return (0);
 215
 216   /* --- Something went wrong --- */
 217
 218 fail:
 219   if (kp->kd) {
 220     key_drop(kp->kd);
 221     kp->kd = 0;
 222   }
 223   return (err);
 224 }
 225
 226 /* --- @key_unpackdone@ --- *
 227  *
 228  * Arguments:   @key_packdef *kp@ = pointer to packing definition
 229  *
 230  * Returns:     ---
 231  *
 232  * Use:         Frees the key components contained within a packing
 233  *              definition, created during key unpacking.
 234  */
 235
 236 void key_unpackdone(key_packdef *kp)
 237 {
 238   if (kp->kd) {
 239     key_drop(kp->kd);
 240     kp->kd = 0;
 241   }
 242   if ((kp->e & KF_ENCMASK) == KENC_STRUCT) {
 243     key_packstruct *p;
 244     for (p = kp->p; p->name; p++)
 245       key_unpackdone(&p->kp);
 246   }
 247 }
 248
 249 /*----- That's all, folks -------------------------------------------------*/