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

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