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

   1 /* -*-c-*-
   2  *
   3  * Packing and unpacking key data
   4  *
   5  * (c) 1999 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of Catacomb.
  11  *
  12  * Catacomb is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU Library General Public License as
  14  * published by the Free Software Foundation; either version 2 of the
  15  * License, or (at your option) any later version.
  16  *
  17  * Catacomb is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU Library General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Library General Public
  23  * License along with Catacomb; if not, write to the Free
  24  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  25  * MA 02111-1307, USA.
  26  */
  27
  28 /*----- Header files ------------------------------------------------------*/
  29
  30 #include <mLib/dstr.h>
  31
  32 #include "key-data.h"
  33
  34 /*----- Generic packing and unpacking -------------------------------------*/
  35
  36 /* --- @key_pack@ --- *
  37  *
  38  * Arguments:   @key_packdef *kp@ = pointer to packing structure
  39  *              @key_data **kd@ = where to put the key data pointer
  40  *              @dstr *d@ = pointer to tag string for the key data
  41  *
  42  * Returns:     Error code, or zero.
  43  *
  44  * Use:         Packs a key from a data structure.
  45  */
  46
  47 int key_pack(key_packdef *kp, key_data **kd, dstr *d)
  48 {
  49   switch (kp->e & KF_ENCMASK) {
  50
  51     /* --- Binary and integer keys are easy --- */
  52
  53     case KENC_BINARY: {
  54       key_bin *b = kp->p;
  55       *kd = key_newbinary(kp->e, b->k, b->sz);
  56       return (0);
  57     }
  58     case KENC_MP:
  59       *kd = key_newmp(kp->e, *(mp **)kp->p);
  60       return (0);
  61     case KENC_STRING:
  62       *kd = key_newstring(kp->e, *(char **)kp->p);
  63       return (0);
  64     case KENC_EC:
  65       *kd = key_newec(kp->e, (ec *)kp->p);
  66       return (0);
  67
  68     /* --- Encrypted keys are a little tricky --- *
  69      *
  70      * This works rather differently to unpacking.
  71      */
  72
  73     case KENC_ENCRYPT: {
  74       key_data *kkd;
  75       int err = key_pack(kp->p, &kkd, d);
  76       if (!err) {
  77         err = key_plock(kd, kkd, d->buf);
  78         key_drop(kkd);
  79       }
  80       return (err);
  81     }
  82
  83     /* --- Structured keys, as ever, are a nuisance --- */
  84
  85     case KENC_STRUCT: {
  86       int err;
  87       key_packstruct *p;
  88       size_t l = d->len;
  89
  90       *kd = key_newstruct();
  91       DPUTC(d, '.');
  92       for (p = kp->p; p->name; p++) {
  93         key_data *kkd;
  94         d->len = l + 1;
  95         DPUTS(d, p->name);
  96         if ((err = key_pack(&p->kp, &kkd, d)) != 0) {
  97           key_drop(*kd);
  98           return (err);
  99         }
 100         key_structsteal(*kd, p->name, kkd);
 101       }
 102       d->len = l;
 103       d->buf[l] = 0;
 104       return (0);
 105     }
 106     default:
 107       abort();
 108   }
 109 }
 110
 111 /* --- @key_unpack@ --- *
 112  *
 113  * Arguments:   @key_packdef *kp@ = pointer to packing structure
 114  *              @key_data *kd@ = pointer to source key data
 115  *              @dstr *d@ = pointer to tag string for the key data
 116  *
 117  * Returns:     Error code, or zero.
 118  *
 119  * Use:         Unpacks a key into an appropriate data structure.
 120  */
 121
 122 int key_unpack(key_packdef *kp, key_data *kd, dstr *d)
 123 {
 124   unsigned e = kp->e & KF_ENCMASK;
 125   int err;
 126
 127   /* --- Decrypt the encrypted key --- */
 128
 129   if ((kd->e & KF_ENCMASK) == KENC_ENCRYPT) {
 130     if ((err = key_punlock(&kp->kd, kd, d->buf)) != 0)
 131       goto fail;
 132     kd = kp->kd;
 133   }
 134
 135   /* --- Ensure that the key has the right type --- */
 136
 137   if ((kd->e & KF_ENCMASK) != e) {
 138     err = KERR_WRONGTYPE;
 139     goto fail;
 140   }
 141
 142   /* --- Unpack the key --- *
 143    *
 144    * Only three possibilities left now.
 145    */
 146
 147   switch (e) {
 148
 149     /* --- Binary and integer keys are easy --- */
 150
 151     case KENC_BINARY:
 152       *(key_bin *)kp->p = kd->u.k;
 153       break;
 154     case KENC_MP:
 155       *(mp **)kp->p = kd->u.m;
 156       break;
 157     case KENC_STRING:
 158       *(char **)kp->p = kd->u.p;
 159       break;
 160     case KENC_EC:
 161       *(ec *)kp->p = kd->u.e;
 162       break;
 163
 164     /* --- Structured keys take a little care --- */
 165
 166     case KENC_STRUCT: {
 167       key_packstruct *p, *q;
 168       size_t l = d->len;
 169
 170       /* --- Iterate over the requested subparts --- */
 171
 172       DPUTC(d, '.');
 173       for (p = kp->p; p->name; p++) {
 174         key_data *kkd;
 175
 176         /* --- Build the name --- */
 177
 178         d->len = l + 1;
 179         DPUTS(d, p->name);
 180
 181         /* --- Find and unpack the subkey --- */
 182
 183         if ((kkd = key_structfind(kd, p->name)) == 0) {
 184           if (!(p->kp.e & KF_OPT)) {
 185             err = KERR_NOTFOUND;
 186             goto tidy;
 187           }
 188         } else if ((err = key_unpack(&p->kp, kkd, d)) != 0) {
 189           p++;
 190           goto tidy;
 191         }
 192       }
 193
 194       /* --- Done --- */
 195
 196       d->len = l;
 197       d->buf[l] = 0;
 198       break;
 199
 200       /* --- Tidy up if something went wrong --- */
 201
 202     tidy:
 203       for (q = kp->p; q < p; q++)
 204         key_unpackdone(&q->kp);
 205       goto fail;
 206     }
 207
 208     default:
 209       abort();
 210   }
 211
 212   return (0);
 213
 214   /* --- Something went wrong --- */
 215
 216 fail:
 217   if (kp->kd) {
 218     key_drop(kp->kd);
 219     kp->kd = 0;
 220   }
 221   return (err);
 222 }
 223
 224 /* --- @key_unpackdone@ --- *
 225  *
 226  * Arguments:   @key_packdef *kp@ = pointer to packing definition
 227  *
 228  * Returns:     ---
 229  *
 230  * Use:         Frees the key components contained within a packing
 231  *              definition, created during key unpacking.
 232  */
 233
 234 void key_unpackdone(key_packdef *kp)
 235 {
 236   if (kp->kd) {
 237     key_drop(kp->kd);
 238     kp->kd = 0;
 239   }
 240   if ((kp->e & KF_ENCMASK) == KENC_STRUCT) {
 241     key_packstruct *p;
 242     for (p = kp->p; p->name; p++)
 243       key_unpackdone(&p->kp);
 244   }
 245 }
 246
 247 /*----- That's all, folks -------------------------------------------------*/