imap_gssapi.h

   1 /*@ S-nail - a mail user agent derived from Berkeley Mail.
   2  *@ Implementation of IMAP GSS-API authentication according to RFC 1731.
   3  *@ TODO GSS-API should also be joined into "a VFS".  TODO LEAKS (error path)
   4  *
   5  * Copyright (c) 2000-2004 Gunnar Ritter, Freiburg i. Br., Germany.
   6  * Copyright (c) 2012 - 2014 Steffen (Daode) Nurpmeso <sdaoden@users.sf.net>.
   7  */
   8 /*
   9  * Copyright (c) 2004 Gunnar Ritter.
  10  * All rights reserved.
  11  *
  12  * Redistribution and use in source and binary forms, with or without
  13  * modification, are permitted provided that the following conditions
  14  * are met:
  15  * 1. Redistributions of source code must retain the above copyright
  16  *    notice, this list of conditions and the following disclaimer.
  17  * 2. Redistributions in binary form must reproduce the above copyright
  18  *    notice, this list of conditions and the following disclaimer in the
  19  *    documentation and/or other materials provided with the distribution.
  20  * 3. All advertising materials mentioning features or use of this software
  21  *    must display the following acknowledgement:
  22  *    This product includes software developed by Gunnar Ritter
  23  *    and his contributors.
  24  * 4. Neither the name of Gunnar Ritter nor the names of his contributors
  25  *    may be used to endorse or promote products derived from this software
  26  *    without specific prior written permission.
  27  *
  28  * THIS SOFTWARE IS PROVIDED BY GUNNAR RITTER AND CONTRIBUTORS ``AS IS'' AND
  29  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  30  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  31  * ARE DISCLAIMED.  IN NO EVENT SHALL GUNNAR RITTER OR CONTRIBUTORS BE LIABLE
  32  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  33  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  34  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  35  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  36  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  37  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  38  * SUCH DAMAGE.
  39  */
  40
  41 /*
  42  * Partially derived from sample code in:
  43  *
  44  * GSS-API Programming Guide
  45  * Part No: 816-1331-11
  46  * Sun Microsystems, Inc. 4150 Network Circle Santa Clara, CA 95054 U.S.A.
  47  *
  48  * (c) 2002 Sun Microsystems
  49  */
  50 /*
  51  * Copyright 1994 by OpenVision Technologies, Inc.
  52  *
  53  * Permission to use, copy, modify, distribute, and sell this software
  54  * and its documentation for any purpose is hereby granted without fee,
  55  * provided that the above copyright notice appears in all copies and
  56  * that both that copyright notice and this permission notice appear in
  57  * supporting documentation, and that the name of OpenVision not be used
  58  * in advertising or publicity pertaining to distribution of the software
  59  * without specific, written prior permission. OpenVision makes no
  60  * representations about the suitability of this software for any
  61  * purpose.  It is provided "as is" without express or implied warranty.
  62  *
  63  * OPENVISION DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
  64  * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
  65  * EVENT SHALL OPENVISION BE LIABLE FOR ANY SPECIAL, INDIRECT OR
  66  * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
  67  * USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
  68  * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  69  * PERFORMANCE OF THIS SOFTWARE.
  70  */
  71
  72 #ifdef HAVE_GSSAPI
  73 #ifndef GSSAPI_REG_INCLUDE
  74 # include <gssapi/gssapi.h>
  75 # ifdef GSSAPI_OLD_STYLE
  76 #  include <gssapi/gssapi_generic.h>
  77 #  define GSS_C_NT_HOSTBASED_SERVICE   gss_nt_service_name
  78 # endif
  79 #else
  80 # include <gssapi.h>
  81 #endif
  82
  83 static void _imap_gssapi_error1(const char *s, OM_uint32 code, int typ);
  84 static void _imap_gssapi_error(const char *s, OM_uint32 maj_stat,
  85                OM_uint32 min_stat);
  86
  87 static void
  88 _imap_gssapi_error1(const char *s, OM_uint32 code, int typ)
  89 {
  90    OM_uint32 maj_stat, min_stat;
  91    gss_buffer_desc msg = GSS_C_EMPTY_BUFFER;
  92    OM_uint32 msg_ctx = 0;
  93    NYD_ENTER;
  94
  95    do {
  96       maj_stat = gss_display_status(&min_stat, code, typ, GSS_C_NO_OID,
  97             &msg_ctx, &msg);
  98       if (maj_stat == GSS_S_COMPLETE) {
  99          fprintf(stderr, "GSS error: %s / %s\n", s, (char*)msg.value);
 100          if (msg.length != 0)
 101             gss_release_buffer(&min_stat, &msg);
 102       } else {
 103          fprintf(stderr, "GSS error: %s / unknown\n", s);
 104          break;
 105       }
 106    } while (msg_ctx);
 107    NYD_LEAVE;
 108 }
 109
 110 static void
 111 _imap_gssapi_error(const char *s, OM_uint32 maj_stat, OM_uint32 min_stat)
 112 {
 113    NYD_ENTER;
 114    _imap_gssapi_error1(s, maj_stat, GSS_C_GSS_CODE);
 115    _imap_gssapi_error1(s, min_stat, GSS_C_MECH_CODE);
 116    NYD_LEAVE;
 117 }
 118
 119 static enum okay
 120 _imap_gssapi(struct mailbox *mp, struct ccred *ccred)
 121 {
 122    char o[LINESIZE];
 123    struct str in, out;
 124    gss_buffer_desc send_tok, recv_tok, *token_ptr;
 125    gss_name_t target_name;
 126    gss_ctx_id_t gss_context;
 127    OM_uint32 maj_stat, min_stat, ret_flags;
 128    int conf_state;
 129    FILE *queuefp = NULL;
 130    char *server, *cp;
 131    enum okay ok = STOP;
 132    NYD_X;
 133
 134    {  size_t i = strlen(mp->mb_imap_account) +1;
 135       server = salloc(i);
 136       memcpy(server, mp->mb_imap_account, i);
 137    }
 138    if (!strncmp(server, "imap://", 7))
 139       server += 7;
 140    else if (!strncmp(server, "imaps://", 8))
 141       server += 8;
 142    if ((cp = UNCONST(last_at_before_slash(server))) != NULL)
 143       server = &cp[1];
 144    for (cp = server; *cp; cp++)
 145       *cp = lowerconv(*cp);
 146    send_tok.value = salloc(send_tok.length = strlen(server) + 6);
 147    snprintf(send_tok.value, send_tok.length, "imap@%s", server);
 148    maj_stat = gss_import_name(&min_stat, &send_tok, GSS_C_NT_HOSTBASED_SERVICE,
 149          &target_name);
 150    if (maj_stat != GSS_S_COMPLETE) {
 151       _imap_gssapi_error(send_tok.value, maj_stat, min_stat);
 152       return STOP;
 153    }
 154    token_ptr = GSS_C_NO_BUFFER;
 155    gss_context = GSS_C_NO_CONTEXT;
 156    maj_stat = gss_init_sec_context(&min_stat,
 157          GSS_C_NO_CREDENTIAL,
 158          &gss_context,
 159          target_name,
 160          GSS_C_NO_OID,
 161          GSS_C_MUTUAL_FLAG|GSS_C_SEQUENCE_FLAG,
 162          0,
 163          GSS_C_NO_CHANNEL_BINDINGS,
 164          token_ptr,
 165          NULL,
 166          &send_tok,
 167          &ret_flags,
 168          NULL);
 169    if (maj_stat != GSS_S_COMPLETE && maj_stat != GSS_S_CONTINUE_NEEDED) {
 170       _imap_gssapi_error("initializing GSS context", maj_stat, min_stat);
 171       gss_release_name(&min_stat, &target_name);
 172       return STOP;
 173    }
 174    snprintf(o, sizeof o, "%s AUTHENTICATE GSSAPI\r\n", tag(1));
 175    IMAP_OUT(o, 0, return STOP);
 176    /*
 177     * No response data expected.
 178     */
 179    imap_answer(mp, 1);
 180    if (response_type != RESPONSE_CONT)
 181       return STOP;
 182    while (maj_stat == GSS_S_CONTINUE_NEEDED) {
 183       /*
 184        * Pass token obtained from first gss_init_sec_context() call.
 185        */
 186       b64_encode_buf(&out, send_tok.value, send_tok.length,
 187          B64_SALLOC | B64_CRLF);
 188       gss_release_buffer(&min_stat, &send_tok);
 189       IMAP_OUT(out.s, 0, return STOP);
 190       imap_answer(mp, 1);
 191       if (response_type != RESPONSE_CONT)
 192          return STOP;
 193       out.s = NULL;
 194       in.s = responded_text;
 195       in.l = strlen(responded_text);
 196       b64_decode(&out, &in, NULL);
 197       recv_tok.value = out.s;
 198       recv_tok.length = out.l;
 199       token_ptr = &recv_tok;
 200       maj_stat = gss_init_sec_context(&min_stat,
 201             GSS_C_NO_CREDENTIAL,
 202             &gss_context,
 203             target_name,
 204             GSS_C_NO_OID,
 205             GSS_C_MUTUAL_FLAG|GSS_C_SEQUENCE_FLAG,
 206             0,
 207             GSS_C_NO_CHANNEL_BINDINGS,
 208             token_ptr,
 209             NULL,
 210             &send_tok,
 211             &ret_flags,
 212             NULL);
 213       free(out.s);
 214       if (maj_stat != GSS_S_COMPLETE && maj_stat != GSS_S_CONTINUE_NEEDED) {
 215          _imap_gssapi_error("initializing context", maj_stat, min_stat);
 216          gss_release_name(&min_stat, &target_name);
 217          return STOP;
 218       }
 219    }
 220    /*
 221     * Pass token obtained from second gss_init_sec_context() call.
 222     */
 223    gss_release_name(&min_stat, &target_name);
 224    b64_encode_buf(&out, send_tok.value, send_tok.length, B64_SALLOC | B64_CRLF);
 225    gss_release_buffer(&min_stat, &send_tok);
 226    IMAP_OUT(out.s, 0, return STOP);
 227    /*
 228     * First octet: bit-mask with protection mechanisms.
 229     * Second to fourth octet: maximum message size in network byte order.
 230     *
 231     * This code currently does not care about the values.
 232     */
 233    imap_answer(mp, 1);
 234    if (response_type != RESPONSE_CONT)
 235       return STOP;
 236    out.s = NULL;
 237    in.s = responded_text;
 238    in.l = strlen(responded_text);
 239    b64_decode(&out, &in, NULL);
 240    recv_tok.value = out.s;
 241    recv_tok.length = out.l;
 242    maj_stat = gss_unwrap(&min_stat, gss_context, &recv_tok, &send_tok,
 243          &conf_state, NULL);
 244    free(out.s);
 245    if (maj_stat != GSS_S_COMPLETE) {
 246       _imap_gssapi_error("unwrapping data", maj_stat, min_stat);
 247       return STOP;
 248    }
 249    /*
 250     * First octet: bit-mask with protection mechanisms (1 = no protection
 251     *    mechanism).
 252     * Second to fourth octet: maximum message size in network byte order.
 253     * Fifth and following octets: user name string.
 254     */
 255    o[0] = 1;
 256    o[1] = 0;
 257    o[2] = o[3] = (char)0377;
 258    snprintf(&o[4], sizeof o - 4, "%s", ccred->cc_user.s);
 259    send_tok.value = o;
 260    send_tok.length = strlen(&o[4]) + 5;
 261    maj_stat = gss_wrap(&min_stat, gss_context, 0, GSS_C_QOP_DEFAULT, &send_tok,
 262          &conf_state, &recv_tok);
 263    if (maj_stat != GSS_S_COMPLETE) {
 264       _imap_gssapi_error("wrapping data", maj_stat, min_stat);
 265       return STOP;
 266    }
 267    b64_encode_buf(&out, recv_tok.value, recv_tok.length, B64_SALLOC | B64_CRLF);
 268    IMAP_OUT(out.s, MB_COMD, return STOP);
 269    while (mp->mb_active & MB_COMD)
 270       ok = imap_answer(mp, 1);
 271    gss_delete_sec_context(&min_stat, &gss_context, &recv_tok);
 272    gss_release_buffer(&min_stat, &recv_tok);
 273    return ok;
 274 }
 275
 276 # undef GSS_C_NT_HOSTBASED_SERVICE
 277 #endif /* HAVE_GSSAPI */
 278
 279 /* vim:set fenc=utf-8:s-it-mode */