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

   1 /* -*-c-*-
   2  *
   3  * $Id: passphrase.c,v 1.6 2004/04/08 01:36:15 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 /*----- Header files ------------------------------------------------------*/
  31
  32 #include <errno.h>
  33 #include <stdio.h>
  34 #include <stdlib.h>
  35 #include <string.h>
  36
  37 #include <unistd.h>
  38
  39 #include <mLib/dstr.h>
  40
  41 #include "passphrase.h"
  42 #include "pixie.h"
  43
  44 /*----- Static variables --------------------------------------------------*/
  45
  46 static int fd = -1;
  47 static unsigned flags = 0;
  48
  49 #define f_fail 1u
  50
  51 /*----- Main code ---------------------------------------------------------*/
  52
  53 /* --- @pconn@ --- *
  54  *
  55  * Arguments:   ---
  56  *
  57  * Returns:     Zero if OK, nonzero if it failed
  58  *
  59  * Use:         Attempts to connect to the passphrase pixie.
  60  */
  61
  62 static int pconn(void)
  63 {
  64   if (fd != -1)
  65     return (0);
  66   if (flags & f_fail)
  67     return (-1);
  68   if ((fd = pixie_open(0)) < 0) {
  69     flags |= f_fail;
  70     return (-1);
  71   }
  72   return (0);
  73 }
  74
  75 /* --- @passphrase_read@ --- *
  76  *
  77  * Arguments:   @const char *tag@ = pointer to passphrase tag string
  78  *              @unsigned mode@ = reading mode
  79  *              @char *buf@ = pointer to destination buffer
  80  *              @size_t sz@ = size of destination buffer
  81  *
  82  * Returns:     Zero if successful, nonzero on failure.
  83  *
  84  * Use:         Reads a passphrase from the user, using some system-specific
  85  *              secure mechanism.  The mechanism may keep a cache of
  86  *              passphrases, so the user may not necessarily be prompted.
  87  */
  88
  89 int passphrase_read(const char *tag, unsigned mode, char *buf, size_t sz)
  90 {
  91   dstr d = DSTR_INIT;
  92   int rc = 1;
  93
  94   /* --- Try talking to the pixie --- */
  95
  96   if (!pconn()) {
  97     rc = pixie_read(fd, tag, mode, buf, sz);
  98     if (rc < 0) {
  99       close(fd);
 100       fd = -1;
 101       return (-1);
 102     }
 103     if (rc == 0)
 104       return (0);
 105   }
 106
 107   /* --- Read from the terminal --- */
 108
 109   dstr_putf(&d, "%s %s: ",
 110             mode == PMODE_READ ? "Passphrase" : "New passphrase",
 111             tag);
 112   if (pixie_getpass(d.buf, buf, sz))
 113     goto fail;
 114   if (mode == PMODE_VERIFY) {
 115     char b[1024];
 116     DRESET(&d);
 117     dstr_putf(&d, "Verify passphrase %s: ", tag);
 118     if (pixie_getpass(d.buf, b, sizeof(b)) || strcmp(b, buf) != 0) {
 119       memset(b, 0, sizeof(b));
 120       goto fail;
 121     }
 122   }
 123   dstr_destroy(&d);
 124
 125   /* --- If the pixie is interested, tell it the new passphrase --- */
 126
 127   if (fd >= 0)
 128     pixie_set(fd, tag, buf);
 129   return (0);
 130
 131   /* --- Tidy up after a failure --- */
 132
 133 fail:
 134   dstr_destroy(&d);
 135   memset(buf, 0, sz);
 136   return (-1);
 137 }
 138
 139 /* --- @passphrase_cancel@ --- *
 140  *
 141  * Arguments:   @const char *tag@ = pointer to passphrase tag string
 142  *
 143  * Returns:     ---
 144  *
 145  * Use:         Attempts to make the passphrase cache forget about a
 146  *              particular passphrase.  This may be useful if the passphrase
 147  *              turns out to be wrong, or if the user is attempting to change
 148  *              the passphrase.
 149  */
 150
 151 void passphrase_cancel(const char *tag)
 152 {
 153   if (!pconn())
 154     pixie_cancel(fd, tag);
 155 }
 156
 157 /*----- That's all, folks -------------------------------------------------*/