mdw@git.distorted.org.uk Git - catacomb/blob - key/passphrase.c

   1 /* -*-c-*-
   2  *
   3  * Reading of passphrases (Unix-specific)
   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 <errno.h>
  31 #include <stdio.h>
  32 #include <stdlib.h>
  33 #include <string.h>
  34
  35 #include <unistd.h>
  36
  37 #include <mLib/dstr.h>
  38 #include <mLib/macros.h>
  39
  40 #include "passphrase.h"
  41 #include "pixie.h"
  42
  43 /*----- Static variables --------------------------------------------------*/
  44
  45 static int fd = -1;
  46 static unsigned flags = 0;
  47
  48 #define f_fail 1u
  49
  50 /*----- Main code ---------------------------------------------------------*/
  51
  52 /* --- @passphrase_connect@ ---
  53  *
  54  * Arguments:   @const char *sock@ = socket name to connect to, or null for
  55  *              default
  56  *
  57  * Returns:     Zero if OK, nonzero if it failed
  58  *
  59  * Use:         Attempts to connect to the passphrase pixie.
  60  */
  61
  62 int passphrase_connect(const char *sock)
  63 {
  64   if (fd != -1)
  65     close(fd);
  66   if ((fd = pixie_open(sock)) < 0) {
  67     flags |= f_fail;
  68     return (-1);
  69   }
  70   flags &= ~f_fail;
  71   return (0);
  72 }
  73
  74 static int pconn(void)
  75 {
  76   if (fd != -1)
  77     return (0);
  78   if (flags & f_fail)
  79     return (-1);
  80   return (passphrase_connect(0));
  81 }
  82
  83 /* --- @passphrase_read@ --- *
  84  *
  85  * Arguments:   @const char *tag@ = pointer to passphrase tag string
  86  *              @unsigned mode@ = reading mode
  87  *              @char *buf@ = pointer to destination buffer
  88  *              @size_t sz@ = size of destination buffer
  89  *
  90  * Returns:     Zero if successful, nonzero on failure.
  91  *
  92  * Use:         Reads a passphrase from the user, using some system-specific
  93  *              secure mechanism.  The mechanism may keep a cache of
  94  *              passphrases, so the user may not necessarily be prompted.
  95  */
  96
  97 int passphrase_read(const char *tag, unsigned mode, char *buf, size_t sz)
  98 {
  99   dstr d = DSTR_INIT;
 100   int rc = 1;
 101
 102   /* --- Try talking to the pixie --- */
 103
 104   if (!pconn()) {
 105     rc = pixie_read(fd, tag, mode, buf, sz);
 106     if (rc < 0) {
 107       close(fd);
 108       fd = -1;
 109       return (-1);
 110     }
 111     if (rc == 0)
 112       return (0);
 113   }
 114
 115   /* --- Read from the terminal --- */
 116
 117   dstr_putf(&d, "%s %s: ",
 118             mode == PMODE_READ ? "Passphrase" : "New passphrase",
 119             tag);
 120   if (pixie_getpass(d.buf, buf, sz))
 121     goto fail;
 122   if (mode == PMODE_VERIFY) {
 123     char b[1024];
 124     DRESET(&d);
 125     dstr_putf(&d, "Verify passphrase %s: ", tag);
 126     if (pixie_getpass(d.buf, b, sizeof(b)) || STRCMP(b, !=, buf)) {
 127       memset(b, 0, sizeof(b));
 128       goto fail;
 129     }
 130   }
 131   dstr_destroy(&d);
 132
 133   /* --- If the pixie is interested, tell it the new passphrase --- */
 134
 135   if (fd >= 0)
 136     pixie_set(fd, tag, buf);
 137   return (0);
 138
 139   /* --- Tidy up after a failure --- */
 140
 141 fail:
 142   dstr_destroy(&d);
 143   memset(buf, 0, sz);
 144   return (-1);
 145 }
 146
 147 /* --- @passphrase_cancel@ --- *
 148  *
 149  * Arguments:   @const char *tag@ = pointer to passphrase tag string
 150  *
 151  * Returns:     ---
 152  *
 153  * Use:         Attempts to make the passphrase cache forget about a
 154  *              particular passphrase.  This may be useful if the passphrase
 155  *              turns out to be wrong, or if the user is attempting to change
 156  *              the passphrase.
 157  */
 158
 159 void passphrase_cancel(const char *tag)
 160 {
 161   if (!pconn())
 162     pixie_cancel(fd, tag);
 163 }
 164
 165 /*----- That's all, folks -------------------------------------------------*/