Pileus Git - ~andy/fetchmail/blob - gssapi.c

   1 /*
   2  * gssapi.c -- GSSAPI authentication (see RFC 1508)
   3  *
   4  * For license terms, see the file COPYING in this directory.
   5  */
   6
   7 #include  "config.h"
   8 #include  <stdio.h>
   9 #include  <string.h>
  10 #include  <ctype.h>
  11 #if defined(STDC_HEADERS)
  12 #include  <stdlib.h>
  13 #endif
  14 #include  "fetchmail.h"
  15 #include  "socket.h"
  16
  17 #include  "i18n.h"
  18 #include "md5.h"
  19
  20 #include <sys/types.h>
  21 #include <netinet/in.h>  /* for htonl/ntohl */
  22
  23 #ifdef GSSAPI
  24 #  ifdef HAVE_GSS_H
  25 #    include <gss.h>
  26 #  else
  27 #  ifdef HAVE_GSSAPI_H
  28 #    include <gssapi.h>
  29 #  endif
  30 #  ifdef HAVE_GSSAPI_GSSAPI_H
  31 #    include <gssapi/gssapi.h>
  32 #  endif
  33 #  ifdef HAVE_GSSAPI_GSSAPI_GENERIC_H
  34 #    include <gssapi/gssapi_generic.h>
  35 #  endif
  36 #  ifndef HAVE_GSS_C_NT_HOSTBASED_SERVICE
  37 #    define GSS_C_NT_HOSTBASED_SERVICE gss_nt_service_name
  38 #  endif
  39 #  endif
  40
  41 #define GSSAUTH_P_NONE      1
  42 #define GSSAUTH_P_INTEGRITY 2
  43 #define GSSAUTH_P_PRIVACY   4
  44
  45 int do_gssauth(int sock, char *command, char *service, char *hostname, char *username)
  46 {
  47     gss_buffer_desc request_buf, send_token;
  48     gss_buffer_t sec_token;
  49     gss_name_t target_name;
  50     gss_ctx_id_t context;
  51     gss_OID mech_name;
  52     gss_qop_t quality;
  53     int cflags;
  54     OM_uint32 maj_stat, min_stat;
  55     char buf1[8192], buf2[8192], server_conf_flags;
  56     unsigned long buf_size;
  57     int result;
  58
  59     /* first things first: get an imap ticket for host */
  60     snprintf(buf1, sizeof(buf1), "%s@%s", service, hostname);
  61     request_buf.value = buf1;
  62     request_buf.length = strlen(buf1) + 1;
  63     maj_stat = gss_import_name(&min_stat, &request_buf, GSS_C_NT_HOSTBASED_SERVICE,
  64         &target_name);
  65     if (maj_stat != GSS_S_COMPLETE) {
  66         report(stderr, GT_("Couldn't get service name for [%s]\n"), buf1);
  67         return PS_AUTHFAIL;
  68     }
  69     else if (outlevel >= O_DEBUG) {
  70         maj_stat = gss_display_name(&min_stat, target_name, &request_buf,
  71             &mech_name);
  72         report(stderr, GT_("Using service name [%s]\n"),
  73                (char *)request_buf.value);
  74         maj_stat = gss_release_buffer(&min_stat, &request_buf);
  75     }
  76
  77     gen_send(sock, "%s GSSAPI", command);
  78
  79     /* upon receipt of the GSSAPI authentication request, server returns
  80      * null data ready response. */
  81     result = gen_recv(sock, buf1, sizeof buf1);
  82     if (result)
  83         return result;
  84
  85     /* now start the security context initialisation loop... */
  86     sec_token = GSS_C_NO_BUFFER;
  87     context = GSS_C_NO_CONTEXT;
  88     if (outlevel >= O_VERBOSE)
  89         report(stdout, GT_("Sending credentials\n"));
  90     do {
  91         send_token.length = 0;
  92         send_token.value = NULL;
  93         maj_stat = gss_init_sec_context(&min_stat,
  94                                         GSS_C_NO_CREDENTIAL,
  95                                         &context,
  96                                         target_name,
  97                                         GSS_C_NO_OID,
  98                                         GSS_C_MUTUAL_FLAG | GSS_C_SEQUENCE_FLAG,
  99                                         0,
 100                                         GSS_C_NO_CHANNEL_BINDINGS,
 101                                         sec_token,
 102                                         NULL,
 103                                         &send_token,
 104                                         NULL,
 105                                         NULL);
 106         if (maj_stat!=GSS_S_COMPLETE && maj_stat!=GSS_S_CONTINUE_NEEDED) {
 107             report(stderr, GT_("Error exchanging credentials\n"));
 108             gss_release_name(&min_stat, &target_name);
 109             /* wake up server and await NO response */
 110             SockWrite(sock, "\r\n", 2);
 111             result = gen_recv(sock, buf1, sizeof buf1);
 112             if (result)
 113                 return result;
 114             return PS_AUTHFAIL;
 115         }
 116         to64frombits(buf1, send_token.value, send_token.length);
 117         gss_release_buffer(&min_stat, &send_token);
 118
 119         suppress_tags = TRUE;
 120         gen_send(sock, buf1, strlen(buf1));
 121         suppress_tags = FALSE;
 122
 123         if (maj_stat == GSS_S_CONTINUE_NEEDED) {
 124             result = gen_recv(sock, buf1, sizeof buf1);
 125             if (result) {
 126                 gss_release_name(&min_stat, &target_name);
 127                 return result;
 128             }
 129             request_buf.length = from64tobits(buf2, buf1 + 2, sizeof(buf2));
 130             if ((int)request_buf.length == -1)  /* in case of bad data */
 131                 request_buf.length = 0;
 132             request_buf.value = buf2;
 133             sec_token = &request_buf;
 134         }
 135     } while
 136         (maj_stat == GSS_S_CONTINUE_NEEDED);
 137     gss_release_name(&min_stat, &target_name);
 138
 139     /* get security flags and buffer size */
 140     result = gen_recv(sock, buf1, sizeof buf1);
 141     if (result)
 142         return result;
 143
 144     request_buf.length = from64tobits(buf2, buf1 + 2, sizeof(buf2));
 145     if ((int)request_buf.length == -1)  /* in case of bad data */
 146         request_buf.length = 0;
 147     request_buf.value = buf2;
 148
 149     maj_stat = gss_unwrap(&min_stat, context,
 150                           &request_buf, &send_token, &cflags, &quality);
 151     if (maj_stat != GSS_S_COMPLETE) {
 152         report(stderr, GT_("Couldn't unwrap security level data\n"));
 153         gss_release_buffer(&min_stat, &send_token);
 154         return PS_AUTHFAIL;
 155     }
 156     if (outlevel >= O_DEBUG)
 157         report(stdout, GT_("Credential exchange complete\n"));
 158     /* first octet is security levels supported. We want none, for now */
 159     server_conf_flags = ((char *)send_token.value)[0];
 160     if ( !(((char *)send_token.value)[0] & GSSAUTH_P_NONE) ) {
 161         report(stderr, GT_("Server requires integrity and/or privacy\n"));
 162         gss_release_buffer(&min_stat, &send_token);
 163         return PS_AUTHFAIL;
 164     }
 165     ((char *)send_token.value)[0] = 0;
 166     buf_size = ntohl(*((long *)send_token.value));
 167     /* we don't care about buffer size if we don't wrap data */
 168     gss_release_buffer(&min_stat, &send_token);
 169     if (outlevel >= O_DEBUG) {
 170         report(stdout, GT_("Unwrapped security level flags: %s%s%s\n"),
 171             server_conf_flags & GSSAUTH_P_NONE ? "N" : "-",
 172             server_conf_flags & GSSAUTH_P_INTEGRITY ? "I" : "-",
 173             server_conf_flags & GSSAUTH_P_PRIVACY ? "C" : "-");
 174         report(stdout, GT_("Maximum GSS token size is %ld\n"),buf_size);
 175     }
 176
 177     /* now respond in kind (hack!!!) */
 178     buf_size = htonl(buf_size); /* do as they do... only matters if we do enc */
 179     memcpy(buf1, &buf_size, 4);
 180     buf1[0] = GSSAUTH_P_NONE;
 181     strlcpy(buf1+4, username, sizeof(buf1) - 4); /* server decides if princ is user */
 182     request_buf.length = 4 + strlen(username) + 1;
 183     request_buf.value = buf1;
 184     maj_stat = gss_wrap(&min_stat, context, 0, GSS_C_QOP_DEFAULT, &request_buf,
 185         &cflags, &send_token);
 186     if (maj_stat != GSS_S_COMPLETE) {
 187         report(stderr, GT_("Error creating security level request\n"));
 188         return PS_AUTHFAIL;
 189     }
 190     to64frombits(buf1, send_token.value, send_token.length);
 191
 192     suppress_tags = TRUE;
 193     result = gen_transact(sock, buf1, strlen(buf1));
 194     suppress_tags = FALSE;
 195
 196     /* flush security context */
 197     if (outlevel >= O_DEBUG)
 198         report(stdout, GT_("Releasing GSS credentials\n"));
 199     maj_stat = gss_delete_sec_context(&min_stat, &context, &send_token);
 200     if (maj_stat != GSS_S_COMPLETE) {
 201         report(stderr, GT_("Error releasing credentials\n"));
 202         return PS_AUTHFAIL;
 203     }
 204     /* send_token may contain a notification to the server to flush
 205      * credentials. RFC 1731 doesn't specify what to do, and since this
 206      * support is only for authentication, we'll assume the server
 207      * knows enough to flush its own credentials */
 208     gss_release_buffer(&min_stat, &send_token);
 209
 210     if (result)
 211         return(result);
 212     else
 213         return(PS_SUCCESS);
 214 }
 215 #endif /* GSSAPI */
 216
 217 /* gssapi.c ends here */