g10/skclist.c

   1 /* skclist.c - Build a list of secret keys
   2  * Copyright (C) 1998, 1999, 2000, 2001, 2006 Free Software Foundation, Inc.
   3  *
   4  * This file is part of GnuPG.
   5  *
   6  * GnuPG is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 3 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * GnuPG is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <config.h>
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <errno.h>
  25 #include <assert.h>
  26
  27 #include "gpg.h"
  28 #include "options.h"
  29 #include "packet.h"
  30 #include "errors.h"
  31 #include "keydb.h"
  32 #include "util.h"
  33 #include "i18n.h"
  34 #include "cipher.h"
  35
  36 #ifndef GCRYCTL_FAKED_RANDOM_P
  37 #define GCRYCTL_FAKED_RANDOM_P 51
  38 #endif
  39
  40 /* Return true if Libgcrypt's RNG is in faked mode.  */
  41 int
  42 random_is_faked (void)
  43 {
  44   /* We use a runtime check to allow for slow migrattion of libgcrypt.
  45      We can't use the constant becuase that one is actually an enum
  46      value.  */
  47   gpg_error_t err = gcry_control ( 51 /*GCRYCTL_FAKED_RANDOM_P*/, 0);
  48
  49   if (!err)
  50     return 0;
  51   if (gpg_err_code (err) != GPG_ERR_INV_OP)
  52     return 1;
  53   log_info ("WARNING: libgcrypt too old.\n");
  54   log_info ("         can't check whether we are in faked RNG mode\n");
  55   return 0; /* Need to return false.  */
  56 }
  57
  58
  59
  60 void
  61 release_sk_list( SK_LIST sk_list )
  62 {
  63     SK_LIST sk_rover;
  64
  65     for( ; sk_list; sk_list = sk_rover ) {
  66         sk_rover = sk_list->next;
  67         free_secret_key( sk_list->sk );
  68         xfree( sk_list );
  69     }
  70 }
  71
  72
  73 /* Check that we are only using keys which don't have
  74  * the string "(insecure!)" or "not secure" or "do not use"
  75  * in one of the user ids
  76  */
  77 static int
  78 is_insecure( PKT_secret_key *sk )
  79 {
  80     u32 keyid[2];
  81     KBNODE node = NULL, u;
  82     int insecure = 0;
  83
  84     keyid_from_sk( sk, keyid );
  85     node = get_pubkeyblock( keyid );
  86     for ( u = node; u; u = u->next ) {
  87         if ( u->pkt->pkttype == PKT_USER_ID ) {
  88             PKT_user_id *id = u->pkt->pkt.user_id;
  89             if ( id->attrib_data )
  90                 continue; /* skip attribute packets */
  91             if ( strstr( id->name, "(insecure!)" )
  92                  || strstr( id->name, "not secure" )
  93                  || strstr( id->name, "do not use" )
  94                  || strstr( id->name, "(INSECURE!)" ) ) {
  95                 insecure = 1;
  96                 break;
  97             }
  98         }
  99     }
 100     release_kbnode( node );
 101
 102     return insecure;
 103 }
 104
 105 static int
 106 key_present_in_sk_list(SK_LIST sk_list, PKT_secret_key *sk)
 107 {
 108     for (; sk_list; sk_list = sk_list->next) {
 109         if ( !cmp_secret_keys(sk_list->sk, sk) )
 110             return 0;
 111     }
 112     return -1;
 113 }
 114
 115 static int
 116 is_duplicated_entry (strlist_t list, strlist_t item)
 117 {
 118     for(; list && list != item; list = list->next) {
 119         if ( !strcmp (list->d, item->d) )
 120             return 1;
 121     }
 122     return 0;
 123 }
 124
 125
 126 int
 127 build_sk_list( strlist_t locusr, SK_LIST *ret_sk_list,
 128                int unlock, unsigned int use )
 129 {
 130     SK_LIST sk_list = NULL;
 131     int rc;
 132
 133     if( !locusr )
 134       { /* use the default one */
 135         PKT_secret_key *sk;
 136
 137         sk = xmalloc_clear( sizeof *sk );
 138         sk->req_usage = use;
 139         if( (rc = get_seckey_byname( sk, NULL, unlock )) ) {
 140           free_secret_key( sk ); sk = NULL;
 141           log_error("no default secret key: %s\n", g10_errstr(rc) );
 142         }
 143         else if( !(rc=openpgp_pk_test_algo2 (sk->pubkey_algo, use)) )
 144           {
 145             SK_LIST r;
 146
 147             if( random_is_faked() && !is_insecure( sk ) )
 148               {
 149                 log_info(_("key is not flagged as insecure - "
 150                            "can't use it with the faked RNG!\n"));
 151                 free_secret_key( sk ); sk = NULL;
 152               }
 153             else
 154               {
 155                 r = xmalloc( sizeof *r );
 156                 r->sk = sk; sk = NULL;
 157                 r->next = sk_list;
 158                 r->mark = 0;
 159                 sk_list = r;
 160               }
 161           }
 162         else
 163           {
 164             free_secret_key( sk ); sk = NULL;
 165             log_error("invalid default secret key: %s\n", g10_errstr(rc) );
 166           }
 167       }
 168     else {
 169         strlist_t locusr_orig = locusr;
 170         for(; locusr; locusr = locusr->next ) {
 171             PKT_secret_key *sk;
 172
 173             rc = 0;
 174             /* Do an early check agains duplicated entries.  However this
 175              * won't catch all duplicates because the user IDs may be
 176              * specified in different ways.
 177              */
 178             if ( is_duplicated_entry ( locusr_orig, locusr ) )
 179               {
 180                 log_error(_("skipped \"%s\": duplicated\n"), locusr->d );
 181                 continue;
 182               }
 183             sk = xmalloc_clear( sizeof *sk );
 184             sk->req_usage = use;
 185             if( (rc = get_seckey_byname( sk, locusr->d, 0 )) )
 186               {
 187                 free_secret_key( sk ); sk = NULL;
 188                 log_error(_("skipped \"%s\": %s\n"),
 189                           locusr->d, g10_errstr(rc) );
 190               }
 191             else if ( key_present_in_sk_list(sk_list, sk) == 0) {
 192                 free_secret_key(sk); sk = NULL;
 193                 log_info(_("skipped: secret key already present\n"));
 194             }
 195             else if ( unlock && (rc = check_secret_key( sk, 0 )) )
 196               {
 197                 free_secret_key( sk ); sk = NULL;
 198                 log_error(_("skipped \"%s\": %s\n"),
 199                           locusr->d, g10_errstr(rc) );
 200               }
 201             else if( !(rc=openpgp_pk_test_algo2 (sk->pubkey_algo, use)) ) {
 202                 SK_LIST r;
 203
 204                 if( sk->version == 4 && (use & PUBKEY_USAGE_SIG)
 205                     && sk->pubkey_algo == PUBKEY_ALGO_ELGAMAL_E )
 206                   {
 207                     log_info(_("skipped \"%s\": %s\n"),locusr->d,
 208                              _("this is a PGP generated Elgamal key which"
 209                                " is not secure for signatures!"));
 210                     free_secret_key( sk ); sk = NULL;
 211                   }
 212                 else if( random_is_faked() && !is_insecure( sk ) ) {
 213                     log_info(_("key is not flagged as insecure - "
 214                                "can't use it with the faked RNG!\n"));
 215                     free_secret_key( sk ); sk = NULL;
 216                 }
 217                 else {
 218                     r = xmalloc( sizeof *r );
 219                     r->sk = sk; sk = NULL;
 220                     r->next = sk_list;
 221                     r->mark = 0;
 222                     sk_list = r;
 223                 }
 224             }
 225             else {
 226                 free_secret_key( sk ); sk = NULL;
 227                 log_error("skipped \"%s\": %s\n", locusr->d, g10_errstr(rc) );
 228             }
 229         }
 230     }
 231
 232
 233     if( !rc && !sk_list ) {
 234         log_error("no valid signators\n");
 235         rc = G10ERR_NO_USER_ID;
 236     }
 237
 238     if( rc )
 239         release_sk_list( sk_list );
 240     else
 241         *ret_sk_list = sk_list;
 242     return rc;
 243 }
 244