pppd/plugins/passwordfd.c

   1
   2 /*
   3  *  Author: Arvin Schnell <arvin@suse.de>
   4  *
   5  *  This plugin let's you pass the password to the pppd via
   6  *  a file descriptor. That's easy and secure - no fiddling
   7  *  with pap- and chap-secrets files.
   8  */
   9
  10 #include <stdio.h>
  11 #include <errno.h>
  12 #include <string.h>
  13 #include <unistd.h>
  14
  15 #include "pppd.h"
  16
  17 char pppd_version[] = VERSION;
  18
  19 static int passwdfd = -1;
  20 static char save_passwd[MAXSECRETLEN];
  21
  22 static option_t options[] = {
  23     { "passwordfd", o_int, &passwdfd,
  24       "Receive password on this file descriptor" },
  25     { NULL }
  26 };
  27
  28 static int pwfd_check (void)
  29 {
  30     return 1;
  31 }
  32
  33 static int pwfd_passwd (char *user, char *passwd)
  34 {
  35     int readgood, red;
  36
  37     if (passwdfd == -1)
  38         return -1;
  39
  40     if (passwd == NULL)
  41         return 1;
  42
  43     if (passwdfd == -2) {
  44         strcpy (passwd, save_passwd);
  45         return 1;
  46     }
  47
  48     readgood = 0;
  49     do {
  50         red = read (passwdfd, passwd + readgood, MAXSECRETLEN - 1 - readgood);
  51         if (red == 0)
  52             break;
  53         if (red < 0) {
  54             error ("Can't read secret from fd\n");
  55             readgood = -1;
  56             break;
  57         }
  58         readgood += red;
  59     } while (readgood < MAXSECRETLEN - 1);
  60
  61     close (passwdfd);
  62
  63     if (readgood < 0)
  64         return 0;
  65
  66     passwd[readgood] = 0;
  67     strcpy (save_passwd, passwd);
  68     passwdfd = -2;
  69
  70     return 1;
  71 }
  72
  73 void plugin_init (void)
  74 {
  75     add_options (options);
  76
  77     pap_check_hook = pwfd_check;
  78     pap_passwd_hook = pwfd_passwd;
  79
  80     chap_check_hook = pwfd_check;
  81     chap_passwd_hook = pwfd_passwd;
  82 }