src/auth-pam.c

   1 /* auth-pam.c -- PAM authentification routine for vlock,
   2  *               the VT locking program for linux
   3  *
   4  * This program is copyright (C) 2007 Frank Benkstein, and is free
   5  * software which is freely distributable under the terms of the
   6  * GNU General Public License version 2, included as the file COPYING in this
   7  * distribution.  It is NOT public domain software, and any
   8  * redistribution not permitted by the GNU General Public License is
   9  * expressly forbidden without prior written permission from
  10  * the author.
  11  *
  12  */
  13
  14 #include <stdio.h>
  15
  16 #include <security/pam_appl.h>
  17 #include <security/pam_misc.h>
  18
  19 int auth(const char *user) {
  20   pam_handle_t *pamh;
  21   int pam_status;
  22   int pam_end_status;
  23   struct pam_conv pamc = {
  24     &misc_conv,
  25     NULL
  26   };
  27
  28   /* initialize pam */
  29   pam_status = pam_start("vlock", user, &pamc, &pamh);
  30
  31   if (pam_status != PAM_SUCCESS) {
  32     fprintf(stderr, "vlock-auth: %s\n", pam_strerror(pamh, pam_status));
  33     goto end;
  34   }
  35
  36   /* put the username before the password prompt */
  37   fprintf(stderr, "%s's ", user); fflush(stderr);
  38   /* authenticate the user */
  39   pam_status = pam_authenticate(pamh, 0);
  40
  41   if (pam_status != PAM_SUCCESS) {
  42     fprintf(stderr, "vlock-auth: %s\n", pam_strerror(pamh, pam_status));
  43   }
  44
  45 end:
  46   /* finish pam */
  47   pam_end_status = pam_end(pamh, pam_status);
  48
  49   if (pam_end_status != PAM_SUCCESS) {
  50     fprintf(stderr, "vlock-auth: %s\n", pam_strerror(pamh, pam_end_status));
  51   }
  52
  53   return (pam_status == PAM_SUCCESS);
  54 }