examples/client-mech.c

   1 /* client-mech.c --- Example SASL client, with a choice of mechanism to use.
   2  * Copyright (C) 2004, 2005, 2007  Simon Josefsson
   3  *
   4  * This file is part of GNU SASL.
   5  *
   6  * This program is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation, either version 3 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  *
  19  */
  20
  21 #include <stdarg.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25
  26 #include <gsasl.h>
  27
  28 static void
  29 client_authenticate (Gsasl * ctx, Gsasl_session * session)
  30 {
  31   char buf[BUFSIZ] = "";
  32   char *p;
  33   int rc;
  34
  35   /* This loop mimic a protocol where the server get to send data first. */
  36
  37   do
  38     {
  39       printf ("Input base64 encoded data from server:\n");
  40       fgets (buf, sizeof (buf) - 1, stdin);
  41       if (buf[strlen (buf) - 1] == '\n')
  42         buf[strlen (buf) - 1] = '\0';
  43
  44       rc = gsasl_step64 (session, buf, &p);
  45
  46       if (rc == GSASL_NEEDS_MORE || rc == GSASL_OK)
  47         {
  48           printf ("Output:\n%s\n", p);
  49           free (p);
  50         }
  51     }
  52   while (rc == GSASL_NEEDS_MORE);
  53
  54   printf ("\n");
  55
  56   if (rc != GSASL_OK)
  57     {
  58       printf ("Authentication error (%d): %s\n", rc, gsasl_strerror (rc));
  59       return;
  60     }
  61
  62   /* The client is done.  Here you would typically check if the server
  63      let the client in.  If not, you could try again. */
  64
  65   printf ("If server accepted us, we're done.\n");
  66 }
  67
  68 static const char *
  69 client_mechanism (Gsasl * ctx)
  70 {
  71   static char mech[GSASL_MAX_MECHANISM_SIZE + 1] = "";
  72   char mechlist[BUFSIZ] = "";
  73   const char *suggestion;
  74
  75   printf ("Enter list of mechanism that server support, separate by SPC:\n");
  76   fgets (mechlist, sizeof (mechlist) - 1, stdin);
  77
  78   suggestion = gsasl_client_suggest_mechanism (ctx, mechlist);
  79   if (suggestion)
  80     printf ("Library suggest use of `%s'.\n", suggestion);
  81
  82   printf ("Enter mechanism to use:\n");
  83   fgets (mech, sizeof (mech) - 1, stdin);
  84   mech[strlen (mech) - 1] = '\0';
  85
  86   return mech;
  87 }
  88
  89 static void
  90 client (Gsasl * ctx)
  91 {
  92   Gsasl_session *session;
  93   const char *mech;
  94   int rc;
  95
  96   /* Find out which mechanism to use. */
  97   mech = client_mechanism (ctx);
  98
  99   /* Create new authentication session. */
 100   if ((rc = gsasl_client_start (ctx, mech, &session)) != GSASL_OK)
 101     {
 102       printf ("Cannot initialize client (%d): %s\n", rc, gsasl_strerror (rc));
 103       return;
 104     }
 105
 106   /* Set username and password in session handle.  This info will be
 107      lost when this session is deallocated below.  */
 108   gsasl_property_set (session, GSASL_AUTHID, "jas");
 109   gsasl_property_set (session, GSASL_PASSWORD, "secret");
 110
 111   /* Do it. */
 112   client_authenticate (ctx, session);
 113
 114   /* Cleanup. */
 115   gsasl_finish (session);
 116 }
 117
 118 int
 119 main (int argc, char *argv[])
 120 {
 121   Gsasl *ctx = NULL;
 122   int rc;
 123
 124   /* Initialize library. */
 125   if ((rc = gsasl_init (&ctx)) != GSASL_OK)
 126     {
 127       printf ("Cannot initialize libgsasl (%d): %s", rc, gsasl_strerror (rc));
 128       return 1;
 129     }
 130
 131   /* Do it. */
 132   client (ctx);
 133
 134   /* Cleanup. */
 135   gsasl_done (ctx);
 136
 137   return 0;
 138 }