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

   1 /* -*-c-*-
   2  *
   3  * $Id: passphrase.c,v 1.5 2002/01/13 13:41:37 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 1.5  2002/01/13 13:41:37  mdw
  34  * Fix stupidity in passphrase verification.
  35  *
  36  * Revision 1.4  2001/04/19 18:26:01  mdw
  37  * Re-request broken passphrases.
  38  *
  39  * Revision 1.3  2000/12/06 20:33:27  mdw
  40  * Make flags be macros rather than enumerations, to ensure that they're
  41  * unsigned.
  42  *
  43  * Revision 1.2  2000/06/17 11:49:37  mdw
  44  * New pixie protocol allowing application to request passphrases and send
  45  * them to the pixie.
  46  *
  47  * Revision 1.1  1999/12/22 15:58:20  mdw
  48  * Portable interface to reading passphrases.
  49  *
  50  */
  51
  52 /*----- Header files ------------------------------------------------------*/
  53
  54 #include <errno.h>
  55 #include <stdio.h>
  56 #include <stdlib.h>
  57 #include <string.h>
  58
  59 #include <unistd.h>
  60
  61 #include <mLib/dstr.h>
  62
  63 #include "passphrase.h"
  64 #include "pixie.h"
  65
  66 /*----- Static variables --------------------------------------------------*/
  67
  68 static int fd = -1;
  69 static unsigned flags = 0;
  70
  71 #define f_fail 1u
  72
  73 /*----- Main code ---------------------------------------------------------*/
  74
  75 /* --- @pconn@ --- *
  76  *
  77  * Arguments:   ---
  78  *
  79  * Returns:     Zero if OK, nonzero if it failed
  80  *
  81  * Use:         Attempts to connect to the passphrase pixie.
  82  */
  83
  84 static int pconn(void)
  85 {
  86   if (fd != -1)
  87     return (0);
  88   if (flags & f_fail)
  89     return (-1);
  90   if ((fd = pixie_open(0)) < 0) {
  91     flags |= f_fail;
  92     return (-1);
  93   }
  94   return (0);
  95 }
  96
  97 /* --- @passphrase_read@ --- *
  98  *
  99  * Arguments:   @const char *tag@ = pointer to passphrase tag string
 100  *              @unsigned mode@ = reading mode
 101  *              @char *buf@ = pointer to destination buffer
 102  *              @size_t sz@ = size of destination buffer
 103  *
 104  * Returns:     Zero if successful, nonzero on failure.
 105  *
 106  * Use:         Reads a passphrase from the user, using some system-specific
 107  *              secure mechanism.  The mechanism may keep a cache of
 108  *              passphrases, so the user may not necessarily be prompted.
 109  */
 110
 111 int passphrase_read(const char *tag, unsigned mode, char *buf, size_t sz)
 112 {
 113   dstr d = DSTR_INIT;
 114   int rc = 1;
 115
 116   /* --- Try talking to the pixie --- */
 117
 118   if (!pconn()) {
 119     rc = pixie_read(fd, tag, mode, buf, sz);
 120     if (rc < 0) {
 121       close(fd);
 122       fd = -1;
 123       return (-1);
 124     }
 125     if (rc == 0)
 126       return (0);
 127   }
 128
 129   /* --- Read from the terminal --- */
 130
 131   dstr_putf(&d, "%s %s: ",
 132             mode == PMODE_READ ? "Passphrase" : "New passphrase",
 133             tag);
 134   if (pixie_getpass(d.buf, buf, sz))
 135     goto fail;
 136   if (mode == PMODE_VERIFY) {
 137     char b[1024];
 138     DRESET(&d);
 139     dstr_putf(&d, "Verify passphrase %s: ", tag);
 140     if (pixie_getpass(d.buf, b, sizeof(b)) || strcmp(b, buf) != 0) {
 141       memset(b, 0, sizeof(b));
 142       goto fail;
 143     }
 144   }
 145   dstr_destroy(&d);
 146
 147   /* --- If the pixie is interested, tell it the new passphrase --- */
 148
 149   if (fd >= 0)
 150     pixie_set(fd, tag, buf);
 151   return (0);
 152
 153   /* --- Tidy up after a failure --- */
 154
 155 fail:
 156   dstr_destroy(&d);
 157   memset(buf, 0, sz);
 158   return (-1);
 159 }
 160
 161 /* --- @passphrase_cancel@ --- *
 162  *
 163  * Arguments:   @const char *tag@ = pointer to passphrase tag string
 164  *
 165  * Returns:     ---
 166  *
 167  * Use:         Attempts to make the passphrase cache forget about a
 168  *              particular passphrase.  This may be useful if the passphrase
 169  *              turns out to be wrong, or if the user is attempting to change
 170  *              the passphrase.
 171  */
 172
 173 void passphrase_cancel(const char *tag)
 174 {
 175   if (!pconn())
 176     pixie_cancel(fd, tag);
 177 }
 178
 179 /*----- That's all, folks -------------------------------------------------*/