authsaslcram.c

   1 /* $Id: authsaslcram.c,v 1.6 2006/06/01 10:47:32 mrsam Exp $ */
   2
   3 /*
   4 ** Copyright 1998 - 2006 Double Precision, Inc.  See COPYING for
   5 ** distribution information.
   6 */
   7
   8 #include        "courier_auth_config.h"
   9 #include        "random128/random128.h"
  10 #include        "courierauthsasl.h"
  11 #include        <stdlib.h>
  12 #include        <string.h>
  13 #if     HAVE_UNISTD_H
  14 #include        <unistd.h>
  15 #endif
  16 #include        <ctype.h>
  17 #include        <stdio.h>
  18 #include        <errno.h>
  19
  20 extern char *strdupdefdomain(const char *userid, const char *s1,
  21                              const char *s2, const char *s3);
  22
  23 int authsasl_cram(const char *method, const char *initresponse,
  24                   char *(*getresp)(const char *, void *),
  25                   void *callback_arg,
  26                   char **authtype,
  27                   char **authdata)
  28 {
  29 const   char *randtoken;
  30 char    hostnamebuf[256];
  31 char    *challenge;
  32 char    *challenge_base64;
  33 char    *response;
  34 char    *chrsp;
  35 char    *q, *r, *s, *t;
  36 int     plen;
  37
  38         if (initresponse && *initresponse)
  39         {
  40                 if (write(2, "authsasl_cram: invalid request.\n", 32) < 0)
  41                         ; /* ignore gcc warning */
  42                 return (AUTHSASL_ERROR);
  43         }
  44
  45         randtoken=random128();
  46         hostnamebuf[0]=0;
  47         if (gethostname(hostnamebuf, sizeof(hostnamebuf)-1))
  48                 strcpy(hostnamebuf, "cram");
  49
  50         challenge=malloc(strlen(randtoken)+strlen(hostnamebuf)
  51                         +sizeof("<@>"));
  52         if (!challenge)
  53         {
  54                 perror("malloc");
  55                 return (AUTHSASL_ERROR);
  56         }
  57         strcat(strcat(strcat(strcat(strcpy(challenge, "<"),
  58                 randtoken), "@"), hostnamebuf), ">");
  59
  60         challenge_base64=authsasl_tobase64(challenge, -1);
  61         free(challenge);
  62         if (!challenge_base64)
  63         {
  64                 perror("malloc");
  65                 return (AUTHSASL_ERROR);
  66         }
  67
  68         response=getresp(challenge_base64, callback_arg);
  69         if (!response)
  70         {
  71                 free(challenge_base64);
  72                 return (AUTHSASL_ERROR);
  73         }
  74
  75         if (*response == '*')
  76         {
  77                 free(challenge_base64);
  78                 free(response);
  79                 return (AUTHSASL_ABORTED);
  80         }
  81
  82         /* If DEFDOMAIN is set, pick apart the response and reassemble
  83          * it, potentially with a default domain appended to the username */
  84         q=getenv("DEFDOMAIN");
  85         if (q && q[0])
  86         {
  87                 r = 0;
  88                 if (    (plen = authsasl_frombase64(response)) > 0 &&
  89                         (response[plen]=0, (s = strchr(response, ' ')) != 0) &&
  90                         (*s++ = 0, (t = strdupdefdomain(response, " ", s, "")) != 0) )
  91                 {
  92                         r = authsasl_tobase64(t, -1);
  93                         free(t);
  94                 }
  95                 free(response);
  96                 if ((response = r) == 0)
  97                 {
  98                         free(challenge_base64);
  99                         return (AUTHSASL_ERROR);
 100                 }
 101         }
 102
 103         chrsp=malloc(strlen(challenge_base64)+strlen(response)+3);
 104         if (!chrsp)
 105         {
 106                 free(challenge_base64);
 107                 free(response);
 108                 perror("malloc");
 109                 return (AUTHSASL_ERROR);
 110         }
 111
 112         strcat(strcat(strcat(strcpy(chrsp, challenge_base64), "\n"),
 113                 response), "\n");
 114         free(challenge_base64);
 115         free(response);
 116
 117         if ( (*authtype=malloc(strlen(method)+1)) == 0)
 118         {
 119                 free(chrsp);
 120                 perror("malloc");
 121                 return (AUTHSASL_ERROR);
 122         }
 123         strcpy( *authtype, method );
 124         *authdata=chrsp;
 125
 126         for (chrsp= *authtype; *chrsp; chrsp++)
 127                 *chrsp= tolower( (int)(unsigned char)*chrsp );
 128
 129         return (AUTHSASL_OK);
 130 }