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