imap_gssapi.c

   1 /*@ S-nail - a mail user agent derived from Berkeley Mail.
   2  *@ Implementation of IMAP GSSAPI authentication according to RFC 1731.
   3  *
   4  * Copyright (c) 2000-2004 Gunnar Ritter, Freiburg i. Br., Germany.
   5  * Copyright (c) 2012 - 2013 Steffen "Daode" Nurpmeso <sdaoden@users.sf.net>.
   6  */
   7 /*
   8  * Copyright (c) 2004
   9  *      Gunnar Ritter.  All rights reserved.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions and the following disclaimer.
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer in the
  18  *    documentation and/or other materials provided with the distribution.
  19  * 3. All advertising materials mentioning features or use of this software
  20  *    must display the following acknowledgement:
  21  *      This product includes software developed by Gunnar Ritter
  22  *      and his contributors.
  23  * 4. Neither the name of Gunnar Ritter nor the names of his contributors
  24  *    may be used to endorse or promote products derived from this software
  25  *    without specific prior written permission.
  26  *
  27  * THIS SOFTWARE IS PROVIDED BY GUNNAR RITTER AND CONTRIBUTORS ``AS IS'' AND
  28  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  29  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  30  * ARE DISCLAIMED.  IN NO EVENT SHALL GUNNAR RITTER OR CONTRIBUTORS BE LIABLE
  31  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  32  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  33  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  34  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  35  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  36  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  37  * SUCH DAMAGE.
  38  */
  39
  40 /*
  41  * Partially derived from sample code in:
  42  *
  43  * GSS-API Programming Guide
  44  * Part No: 816-1331-11
  45  * Sun Microsystems, Inc. 4150 Network Circle Santa Clara, CA 95054 U.S.A.
  46  *
  47  * (c) 2002 Sun Microsystems
  48  */
  49 /*
  50  * Copyright 1994 by OpenVision Technologies, Inc.
  51  *
  52  * Permission to use, copy, modify, distribute, and sell this software
  53  * and its documentation for any purpose is hereby granted without fee,
  54  * provided that the above copyright notice appears in all copies and
  55  * that both that copyright notice and this permission notice appear in
  56  * supporting documentation, and that the name of OpenVision not be used
  57  * in advertising or publicity pertaining to distribution of the software
  58  * without specific, written prior permission. OpenVision makes no
  59  * representations about the suitability of this software for any
  60  * purpose.  It is provided "as is" without express or implied warranty.
  61  *
  62  * OPENVISION DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
  63  * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
  64  * EVENT SHALL OPENVISION BE LIABLE FOR ANY SPECIAL, INDIRECT OR
  65  * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
  66  * USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
  67  * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  68  * PERFORMANCE OF THIS SOFTWARE.
  69  */
  70
  71 #ifdef HAVE_GSSAPI
  72
  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_gss_error1(const char *s, OM_uint32 code, int type);
  84 static void imap_gss_error(const char *s, OM_uint32 maj_stat,
  85                 OM_uint32 min_stat);
  86 static void
  87 imap_gss_error1(const char *s, OM_uint32 code, int type)
  88 {
  89         OM_uint32       maj_stat, min_stat;
  90         gss_buffer_desc msg = GSS_C_EMPTY_BUFFER;
  91         OM_uint32       msg_ctx = 0;
  92
  93         do {
  94                 maj_stat = gss_display_status(&min_stat, code, type,
  95                                 GSS_C_NO_OID, &msg_ctx, &msg);
  96                 if (maj_stat == GSS_S_COMPLETE) {
  97                         fprintf(stderr, "GSS error: %s / %s\n",
  98                                         s,
  99                                         (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 }
 108
 109 static void
 110 imap_gss_error(const char *s, OM_uint32 maj_stat, OM_uint32 min_stat)
 111 {
 112         imap_gss_error1(s, maj_stat, GSS_C_GSS_CODE);
 113         imap_gss_error1(s, min_stat, GSS_C_MECH_CODE);
 114 }
 115
 116 static enum okay
 117 imap_gss(struct mailbox *mp, char *user)
 118 {
 119         gss_buffer_desc send_tok, recv_tok, *token_ptr;
 120         gss_name_t      target_name;
 121         gss_ctx_id_t    gss_context;
 122         OM_uint32       maj_stat, min_stat, ret_flags;
 123         int     conf_state;
 124         struct str      in, out;
 125         FILE    *queuefp = NULL;
 126         char    *server, *cp;
 127         char    o[LINESIZE];
 128         enum okay       ok = STOP;
 129
 130         if (user == NULL) {
 131                 if ((user = getuser(NULL)) == NULL)
 132                         return STOP;
 133                 user = savestr(user);
 134         }
 135         {       size_t i = strlen(mp->mb_imap_account) + 1;
 136                 server = salloc(i);
 137                 memcpy(server, mp->mb_imap_account, i);
 138         }
 139         if (strncmp(server, "imap://", 7) == 0)
 140                 server += 7;
 141         else if (strncmp(server, "imaps://", 8) == 0)
 142                 server += 8;
 143         if ((cp = UNCONST(last_at_before_slash(server))) != NULL)
 144                 server = &cp[1];
 145         for (cp = server; *cp; cp++)
 146                 *cp = lowerconv(*cp);
 147         send_tok.value = salloc(send_tok.length = strlen(server) + 6);
 148         snprintf(send_tok.value, send_tok.length, "imap@%s", server);
 149         maj_stat = gss_import_name(&min_stat, &send_tok,
 150                         GSS_C_NT_HOSTBASED_SERVICE, &target_name);
 151         if (maj_stat != GSS_S_COMPLETE) {
 152                 imap_gss_error(send_tok.value, maj_stat, min_stat);
 153                 return STOP;
 154         }
 155         token_ptr = GSS_C_NO_BUFFER;
 156         gss_context = GSS_C_NO_CONTEXT;
 157         maj_stat = gss_init_sec_context(&min_stat,
 158                         GSS_C_NO_CREDENTIAL,
 159                         &gss_context,
 160                         target_name,
 161                         GSS_C_NO_OID,
 162                         GSS_C_MUTUAL_FLAG|GSS_C_SEQUENCE_FLAG,
 163                         0,
 164                         GSS_C_NO_CHANNEL_BINDINGS,
 165                         token_ptr,
 166                         NULL,
 167                         &send_tok,
 168                         &ret_flags,
 169                         NULL);
 170         if (maj_stat != GSS_S_COMPLETE && maj_stat != GSS_S_CONTINUE_NEEDED) {
 171                 imap_gss_error("initializing GSS context", maj_stat, min_stat);
 172                 gss_release_name(&min_stat, &target_name);
 173                 return STOP;
 174         }
 175         snprintf(o, sizeof o, "%s AUTHENTICATE GSSAPI\r\n", tag(1));
 176         IMAP_OUT(o, 0, return STOP);
 177         /*
 178          * No response data expected.
 179          */
 180         imap_answer(mp, 1);
 181         if (response_type != RESPONSE_CONT)
 182                 return STOP;
 183         while (maj_stat == GSS_S_CONTINUE_NEEDED) {
 184                 /*
 185                  * Pass token obtained from first gss_init_sec_context() call.
 186                  */
 187                 (void)b64_encode_buf(&out, send_tok.value, send_tok.length,
 188                         B64_SALLOC|B64_CRLF);
 189                 gss_release_buffer(&min_stat, &send_tok);
 190                 IMAP_OUT(out.s, 0, return STOP);
 191                 imap_answer(mp, 1);
 192                 if (response_type != RESPONSE_CONT)
 193                         return STOP;
 194                 out.s = NULL;
 195                 in.s = responded_text;
 196                 in.l = strlen(responded_text);
 197                 (void)b64_decode(&out, &in, NULL);
 198                 recv_tok.value = out.s;
 199                 recv_tok.length = out.l;
 200                 token_ptr = &recv_tok;
 201                 maj_stat = gss_init_sec_context(&min_stat,
 202                                 GSS_C_NO_CREDENTIAL,
 203                                 &gss_context,
 204                                 target_name,
 205                                 GSS_C_NO_OID,
 206                                 GSS_C_MUTUAL_FLAG|GSS_C_SEQUENCE_FLAG,
 207                                 0,
 208                                 GSS_C_NO_CHANNEL_BINDINGS,
 209                                 token_ptr,
 210                                 NULL,
 211                                 &send_tok,
 212                                 &ret_flags,
 213                                 NULL);
 214                 if (maj_stat != GSS_S_COMPLETE &&
 215                                 maj_stat != GSS_S_CONTINUE_NEEDED) {
 216                         imap_gss_error("initializing context",
 217                                         maj_stat, min_stat);
 218                         gss_release_name(&min_stat, &target_name);
 219                         return STOP;
 220                 }
 221                 free(out.s);
 222         }
 223         /*
 224          * Pass token obtained from second gss_init_sec_context() call.
 225          */
 226         gss_release_name(&min_stat, &target_name);
 227         (void)b64_encode_buf(&out, send_tok.value, send_tok.length,
 228                 B64_SALLOC|B64_CRLF);
 229         gss_release_buffer(&min_stat, &send_tok);
 230         IMAP_OUT(out.s, 0, return STOP);
 231         /*
 232          * First octet: bit-mask with protection mechanisms.
 233          * Second to fourth octet: maximum message size in network byte order.
 234          *
 235          * This code currently does not care about the values.
 236          */
 237         imap_answer(mp, 1);
 238         if (response_type != RESPONSE_CONT)
 239                 return STOP;
 240         out.s = NULL;
 241         in.s = responded_text;
 242         in.l = strlen(responded_text);
 243         (void)b64_decode(&out, &in, NULL);
 244         recv_tok.value = out.s;
 245         recv_tok.length = out.l;
 246         maj_stat = gss_unwrap(&min_stat, gss_context, &recv_tok,
 247                         &send_tok, &conf_state, NULL);
 248         free(out.s);
 249         if (maj_stat != GSS_S_COMPLETE) {
 250                 imap_gss_error("unwrapping data", maj_stat, min_stat);
 251                 return STOP;
 252         }
 253         /*
 254          * First octet: bit-mask with protection mechanisms (1 = no protection
 255          *      mechanism).
 256          * Second to fourth octet: maximum message size in network byte order.
 257          * Fifth and following octets: user name string.
 258          */
 259         o[0] = 1;
 260         o[1] = 0;
 261         o[2] = o[3] = (char)0377;
 262         snprintf(&o[4], sizeof o - 4, "%s", user);
 263         send_tok.value = o;
 264         send_tok.length = strlen(&o[4]) + 5;
 265         maj_stat = gss_wrap(&min_stat, gss_context, 0, GSS_C_QOP_DEFAULT,
 266                         &send_tok, &conf_state, &recv_tok);
 267         if (maj_stat != GSS_S_COMPLETE) {
 268                 imap_gss_error("wrapping data", maj_stat, min_stat);
 269                 return STOP;
 270         }
 271         (void)b64_encode_buf(&out, recv_tok.value, recv_tok.length,
 272                 B64_SALLOC|B64_CRLF);
 273         IMAP_OUT(out.s, MB_COMD, return STOP);
 274         while (mp->mb_active & MB_COMD)
 275                 ok = imap_answer(mp, 1);
 276         gss_delete_sec_context(&min_stat, &gss_context, &recv_tok);
 277         gss_release_buffer(&min_stat, &recv_tok);
 278         return ok;
 279 }
 280
 281 #endif /* HAVE_GSSAPI */