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

   1 /* -*-c-*-
   2  *
   3  * $Id: passphrase.c,v 1.3 2000/12/06 20:33:27 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 1.3  2000/12/06 20:33:27  mdw
  34  * Make flags be macros rather than enumerations, to ensure that they're
  35  * unsigned.
  36  *
  37  * Revision 1.2  2000/06/17 11:49:37  mdw
  38  * New pixie protocol allowing application to request passphrases and send
  39  * them to the pixie.
  40  *
  41  * Revision 1.1  1999/12/22 15:58:20  mdw
  42  * Portable interface to reading passphrases.
  43  *
  44  */
  45
  46 /*----- Header files ------------------------------------------------------*/
  47
  48 #include <errno.h>
  49 #include <stdio.h>
  50 #include <stdlib.h>
  51 #include <string.h>
  52
  53 #include <unistd.h>
  54
  55 #include <mLib/dstr.h>
  56
  57 #include "passphrase.h"
  58 #include "pixie.h"
  59
  60 /*----- Static variables --------------------------------------------------*/
  61
  62 static int fd = -1;
  63 static unsigned flags = 0;
  64
  65 #define f_fail 1u
  66
  67 /*----- Main code ---------------------------------------------------------*/
  68
  69 /* --- @pconn@ --- *
  70  *
  71  * Arguments:   ---
  72  *
  73  * Returns:     Zero if OK, nonzero if it failed
  74  *
  75  * Use:         Attempts to connect to the passphrase pixie.
  76  */
  77
  78 static int pconn(void)
  79 {
  80   if (fd != -1)
  81     return (0);
  82   if (flags & f_fail)
  83     return (-1);
  84   if ((fd = pixie_open(0)) < 0) {
  85     flags |= f_fail;
  86     return (-1);
  87   }
  88   return (0);
  89 }
  90
  91 /* --- @passphrase_read@ --- *
  92  *
  93  * Arguments:   @const char *tag@ = pointer to passphrase tag string
  94  *              @unsigned mode@ = reading mode
  95  *              @char *buf@ = pointer to destination buffer
  96  *              @size_t sz@ = size of destination buffer
  97  *
  98  * Returns:     Zero if successful, nonzero on failure.
  99  *
 100  * Use:         Reads a passphrase from the user, using some system-specific
 101  *              secure mechanism.  The mechanism may keep a cache of
 102  *              passphrases, so the user may not necessarily be prompted.
 103  */
 104
 105 int passphrase_read(const char *tag, unsigned mode, char *buf, size_t sz)
 106 {
 107   dstr d = DSTR_INIT;
 108   int rc = 1;
 109
 110   /* --- Try talking to the pixie --- */
 111
 112   if (!pconn()) {
 113     rc = pixie_read(fd, tag, mode, buf, sz);
 114     if (rc < 0) {
 115       close(fd);
 116       fd = -1;
 117       return (-1);
 118     }
 119     if (rc == 0)
 120       return (0);
 121   }
 122
 123   /* --- Read from the terminal --- */
 124
 125   dstr_putf(&d, "%s %s: ",
 126             mode == PMODE_READ ? "Passphrase" : "New passphrase",
 127             tag);
 128   if (pixie_getpass(d.buf, buf, sz))
 129     goto fail;
 130   if (mode == PMODE_VERIFY) {
 131     char b[1024];
 132     DRESET(&d);
 133     dstr_putf(&d, "Verify passphrase %s: ", tag);
 134     if (pixie_getpass(d.buf, b, sizeof(b)) ||
 135         strcmp(b, buf) != 0) {
 136       memset(b, 0, sizeof(b));
 137       goto fail;
 138     }
 139   }
 140   dstr_destroy(&d);
 141
 142   /* --- If the pixie is interested, tell it the new passphrase --- */
 143
 144   if (fd >= 0)
 145     pixie_set(fd, tag, buf);
 146   return (0);
 147
 148   /* --- Tidy up after a failure --- */
 149
 150 fail:
 151   dstr_destroy(&d);
 152   memset(buf, 0, sz);
 153   return (-1);
 154 }
 155
 156 /* --- @passphrase_cancel@ --- *
 157  *
 158  * Arguments:   @const char *tag@ = pointer to passphrase tag string
 159  *
 160  * Returns:     ---
 161  *
 162  * Use:         Attempts to make the passphrase cache forget about a
 163  *              particular passphrase.  This may be useful if the passphrase
 164  *              turns out to be wrong, or if the user is attempting to change
 165  *              the passphrase.
 166  */
 167
 168 void passphrase_cancel(const char *tag)
 169 {
 170   if (!pconn())
 171     pixie_cancel(fd, tag);
 172 }
 173
 174 /*----- That's all, folks -------------------------------------------------*/