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

   1 /* -*-c-*-
   2  *
   3  * $Id: passphrase.c,v 1.2 2000/06/17 11:49:37 mdw Exp $
   4  *
   5  * Reading of passphrases (Unix-specific)
   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: passphrase.c,v $
  33  * Revision 1.2  2000/06/17 11:49:37  mdw
  34  * New pixie protocol allowing application to request passphrases and send
  35  * them to the pixie.
  36  *
  37  * Revision 1.1  1999/12/22 15:58:20  mdw
  38  * Portable interface to reading passphrases.
  39  *
  40  */
  41
  42 /*----- Header files ------------------------------------------------------*/
  43
  44 #include <errno.h>
  45 #include <stdio.h>
  46 #include <stdlib.h>
  47 #include <string.h>
  48
  49 #include <unistd.h>
  50
  51 #include <mLib/dstr.h>
  52
  53 #include "passphrase.h"
  54 #include "pixie.h"
  55
  56 /*----- Static variables --------------------------------------------------*/
  57
  58 static int fd = -1;
  59 static unsigned flags = 0;
  60
  61 enum {
  62   f_fail = 1
  63 };
  64
  65 /*----- Main code ---------------------------------------------------------*/
  66
  67 /* --- @pconn@ --- *
  68  *
  69  * Arguments:   ---
  70  *
  71  * Returns:     Zero if OK, nonzero if it failed
  72  *
  73  * Use:         Attempts to connect to the passphrase pixie.
  74  */
  75
  76 static int pconn(void)
  77 {
  78   if (fd != -1)
  79     return (0);
  80   if (flags & f_fail)
  81     return (-1);
  82   if ((fd = pixie_open(0)) < 0) {
  83     flags |= f_fail;
  84     return (-1);
  85   }
  86   return (0);
  87 }
  88
  89 /* --- @passphrase_read@ --- *
  90  *
  91  * Arguments:   @const char *tag@ = pointer to passphrase tag string
  92  *              @unsigned mode@ = reading mode
  93  *              @char *buf@ = pointer to destination buffer
  94  *              @size_t sz@ = size of destination buffer
  95  *
  96  * Returns:     Zero if successful, nonzero on failure.
  97  *
  98  * Use:         Reads a passphrase from the user, using some system-specific
  99  *              secure mechanism.  The mechanism may keep a cache of
 100  *              passphrases, so the user may not necessarily be prompted.
 101  */
 102
 103 int passphrase_read(const char *tag, unsigned mode, char *buf, size_t sz)
 104 {
 105   dstr d = DSTR_INIT;
 106   int rc = 1;
 107
 108   /* --- Try talking to the pixie --- */
 109
 110   if (!pconn()) {
 111     rc = pixie_read(fd, tag, mode, buf, sz);
 112     if (rc < 0) {
 113       close(fd);
 114       fd = -1;
 115       return (-1);
 116     }
 117     if (rc == 0)
 118       return (0);
 119   }
 120
 121   /* --- Read from the terminal --- */
 122
 123   dstr_putf(&d, "%s %s: ",
 124             mode == PMODE_READ ? "Passphrase" : "New passphrase",
 125             tag);
 126   if (pixie_getpass(d.buf, buf, sz))
 127     goto fail;
 128   if (mode == PMODE_VERIFY) {
 129     char b[1024];
 130     DRESET(&d);
 131     dstr_putf(&d, "Verify passphrase %s: ", tag);
 132     if (pixie_getpass(d.buf, b, sizeof(b)) ||
 133         strcmp(b, buf) != 0) {
 134       memset(b, 0, sizeof(b));
 135       goto fail;
 136     }
 137   }
 138   dstr_destroy(&d);
 139
 140   /* --- If the pixie is interested, tell it the new passphrase --- */
 141
 142   if (fd >= 0)
 143     pixie_set(fd, tag, buf);
 144   return (0);
 145
 146   /* --- Tidy up after a failure --- */
 147
 148 fail:
 149   dstr_destroy(&d);
 150   memset(buf, 0, sz);
 151   return (-1);
 152 }
 153
 154 /* --- @passphrase_cancel@ --- *
 155  *
 156  * Arguments:   @const char *tag@ = pointer to passphrase tag string
 157  *
 158  * Returns:     ---
 159  *
 160  * Use:         Attempts to make the passphrase cache forget about a
 161  *              particular passphrase.  This may be useful if the passphrase
 162  *              turns out to be wrong, or if the user is attempting to change
 163  *              the passphrase.
 164  */
 165
 166 void passphrase_cancel(const char *tag)
 167 {
 168   if (!pconn())
 169     pixie_cancel(fd, tag);
 170 }
 171
 172 /*----- That's all, folks -------------------------------------------------*/