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

   1 /* -*-c-*-
   2  *
   3  * Reading of passphrases (Unix-specific)
   4  *
   5  * (c) 1999 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of Catacomb.
  11  *
  12  * Catacomb is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU Library General Public License as
  14  * published by the Free Software Foundation; either version 2 of the
  15  * License, or (at your option) any later version.
  16  *
  17  * Catacomb is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU Library General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Library General Public
  23  * License along with Catacomb; if not, write to the Free
  24  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  25  * MA 02111-1307, USA.
  26  */
  27
  28 /*----- Header files ------------------------------------------------------*/
  29
  30 #include <errno.h>
  31 #include <stdio.h>
  32 #include <stdlib.h>
  33 #include <string.h>
  34
  35 #include <unistd.h>
  36
  37 #include <mLib/dstr.h>
  38
  39 #include "passphrase.h"
  40 #include "pixie.h"
  41
  42 /*----- Static variables --------------------------------------------------*/
  43
  44 static int fd = -1;
  45 static unsigned flags = 0;
  46
  47 #define f_fail 1u
  48
  49 /*----- Main code ---------------------------------------------------------*/
  50
  51 /* --- @passphrase_connect@ ---
  52  *
  53  * Arguments:   @const char *sock@ = socket name to connect to, or null for
  54  *              default
  55  *
  56  * Returns:     Zero if OK, nonzero if it failed
  57  *
  58  * Use:         Attempts to connect to the passphrase pixie.
  59  */
  60
  61 int passphrase_connect(const char *sock)
  62 {
  63   if (fd != -1)
  64     close(fd);
  65   if ((fd = pixie_open(sock)) < 0) {
  66     flags |= f_fail;
  67     return (-1);
  68   }
  69   flags &= ~f_fail;
  70   return (0);
  71 }
  72
  73 static int pconn(void)
  74 {
  75   if (fd != -1)
  76     return (0);
  77   if (flags & f_fail)
  78     return (-1);
  79   return (passphrase_connect(0));
  80 }
  81
  82 /* --- @passphrase_read@ --- *
  83  *
  84  * Arguments:   @const char *tag@ = pointer to passphrase tag string
  85  *              @unsigned mode@ = reading mode
  86  *              @char *buf@ = pointer to destination buffer
  87  *              @size_t sz@ = size of destination buffer
  88  *
  89  * Returns:     Zero if successful, nonzero on failure.
  90  *
  91  * Use:         Reads a passphrase from the user, using some system-specific
  92  *              secure mechanism.  The mechanism may keep a cache of
  93  *              passphrases, so the user may not necessarily be prompted.
  94  */
  95
  96 int passphrase_read(const char *tag, unsigned mode, char *buf, size_t sz)
  97 {
  98   dstr d = DSTR_INIT;
  99   int rc = 1;
 100
 101   /* --- Try talking to the pixie --- */
 102
 103   if (!pconn()) {
 104     rc = pixie_read(fd, tag, mode, buf, sz);
 105     if (rc < 0) {
 106       close(fd);
 107       fd = -1;
 108       return (-1);
 109     }
 110     if (rc == 0)
 111       return (0);
 112   }
 113
 114   /* --- Read from the terminal --- */
 115
 116   dstr_putf(&d, "%s %s: ",
 117             mode == PMODE_READ ? "Passphrase" : "New passphrase",
 118             tag);
 119   if (pixie_getpass(d.buf, buf, sz))
 120     goto fail;
 121   if (mode == PMODE_VERIFY) {
 122     char b[1024];
 123     DRESET(&d);
 124     dstr_putf(&d, "Verify passphrase %s: ", tag);
 125     if (pixie_getpass(d.buf, b, sizeof(b)) || strcmp(b, buf) != 0) {
 126       memset(b, 0, sizeof(b));
 127       goto fail;
 128     }
 129   }
 130   dstr_destroy(&d);
 131
 132   /* --- If the pixie is interested, tell it the new passphrase --- */
 133
 134   if (fd >= 0)
 135     pixie_set(fd, tag, buf);
 136   return (0);
 137
 138   /* --- Tidy up after a failure --- */
 139
 140 fail:
 141   dstr_destroy(&d);
 142   memset(buf, 0, sz);
 143   return (-1);
 144 }
 145
 146 /* --- @passphrase_cancel@ --- *
 147  *
 148  * Arguments:   @const char *tag@ = pointer to passphrase tag string
 149  *
 150  * Returns:     ---
 151  *
 152  * Use:         Attempts to make the passphrase cache forget about a
 153  *              particular passphrase.  This may be useful if the passphrase
 154  *              turns out to be wrong, or if the user is attempting to change
 155  *              the passphrase.
 156  */
 157
 158 void passphrase_cancel(const char *tag)
 159 {
 160   if (!pconn())
 161     pixie_cancel(fd, tag);
 162 }
 163
 164 /*----- That's all, folks -------------------------------------------------*/