crypto/openssh-4/gss-genr.c

   1 /*      $OpenBSD: gss-genr.c,v 1.3 2003/11/21 11:57:03 djm Exp $        */
   2
   3 /*
   4  * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR `AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  */
  26
  27 #include "includes.h"
  28
  29 #ifdef GSSAPI
  30
  31 #include "xmalloc.h"
  32 #include "bufaux.h"
  33 #include "compat.h"
  34 #include "log.h"
  35 #include "monitor_wrap.h"
  36 #include "ssh2.h"
  37
  38 #include "ssh-gss.h"
  39
  40 extern u_char *session_id2;
  41 extern u_int session_id2_len;
  42
  43 /* Check that the OID in a data stream matches that in the context */
  44 int
  45 ssh_gssapi_check_oid(Gssctxt *ctx, void *data, size_t len)
  46 {
  47         return (ctx != NULL && ctx->oid != GSS_C_NO_OID &&
  48             ctx->oid->length == len &&
  49             memcmp(ctx->oid->elements, data, len) == 0);
  50 }
  51
  52 /* Set the contexts OID from a data stream */
  53 void
  54 ssh_gssapi_set_oid_data(Gssctxt *ctx, void *data, size_t len)
  55 {
  56         if (ctx->oid != GSS_C_NO_OID) {
  57                 xfree(ctx->oid->elements);
  58                 xfree(ctx->oid);
  59         }
  60         ctx->oid = xmalloc(sizeof(gss_OID_desc));
  61         ctx->oid->length = len;
  62         ctx->oid->elements = xmalloc(len);
  63         memcpy(ctx->oid->elements, data, len);
  64 }
  65
  66 /* Set the contexts OID */
  67 void
  68 ssh_gssapi_set_oid(Gssctxt *ctx, gss_OID oid)
  69 {
  70         ssh_gssapi_set_oid_data(ctx, oid->elements, oid->length);
  71 }
  72
  73 /* All this effort to report an error ... */
  74 void
  75 ssh_gssapi_error(Gssctxt *ctxt)
  76 {
  77         debug("%s", ssh_gssapi_last_error(ctxt, NULL, NULL));
  78 }
  79
  80 char *
  81 ssh_gssapi_last_error(Gssctxt *ctxt,
  82                       OM_uint32 *major_status, OM_uint32 *minor_status)
  83 {
  84         OM_uint32 lmin;
  85         gss_buffer_desc msg = GSS_C_EMPTY_BUFFER;
  86         OM_uint32 ctx;
  87         Buffer b;
  88         char *ret;
  89
  90         buffer_init(&b);
  91
  92         if (major_status != NULL)
  93                 *major_status = ctxt->major;
  94         if (minor_status != NULL)
  95                 *minor_status = ctxt->minor;
  96
  97         ctx = 0;
  98         /* The GSSAPI error */
  99         do {
 100                 gss_display_status(&lmin, ctxt->major,
 101                     GSS_C_GSS_CODE, GSS_C_NULL_OID, &ctx, &msg);
 102
 103                 buffer_append(&b, msg.value, msg.length);
 104                 buffer_put_char(&b, '\n');
 105
 106                 gss_release_buffer(&lmin, &msg);
 107         } while (ctx != 0);
 108
 109         /* The mechanism specific error */
 110         do {
 111                 gss_display_status(&lmin, ctxt->minor,
 112                     GSS_C_MECH_CODE, GSS_C_NULL_OID, &ctx, &msg);
 113
 114                 buffer_append(&b, msg.value, msg.length);
 115                 buffer_put_char(&b, '\n');
 116
 117                 gss_release_buffer(&lmin, &msg);
 118         } while (ctx != 0);
 119
 120         buffer_put_char(&b, '\0');
 121         ret = xmalloc(buffer_len(&b));
 122         buffer_get(&b, ret, buffer_len(&b));
 123         buffer_free(&b);
 124         return (ret);
 125 }
 126
 127 /*
 128  * Initialise our GSSAPI context. We use this opaque structure to contain all
 129  * of the data which both the client and server need to persist across
 130  * {accept,init}_sec_context calls, so that when we do it from the userauth
 131  * stuff life is a little easier
 132  */
 133 void
 134 ssh_gssapi_build_ctx(Gssctxt **ctx)
 135 {
 136         *ctx = xmalloc(sizeof (Gssctxt));
 137         (*ctx)->major = 0;
 138         (*ctx)->minor = 0;
 139         (*ctx)->context = GSS_C_NO_CONTEXT;
 140         (*ctx)->name = GSS_C_NO_NAME;
 141         (*ctx)->oid = GSS_C_NO_OID;
 142         (*ctx)->creds = GSS_C_NO_CREDENTIAL;
 143         (*ctx)->client = GSS_C_NO_NAME;
 144         (*ctx)->client_creds = GSS_C_NO_CREDENTIAL;
 145 }
 146
 147 /* Delete our context, providing it has been built correctly */
 148 void
 149 ssh_gssapi_delete_ctx(Gssctxt **ctx)
 150 {
 151         OM_uint32 ms;
 152
 153         if ((*ctx) == NULL)
 154                 return;
 155         if ((*ctx)->context != GSS_C_NO_CONTEXT)
 156                 gss_delete_sec_context(&ms, &(*ctx)->context, GSS_C_NO_BUFFER);
 157         if ((*ctx)->name != GSS_C_NO_NAME)
 158                 gss_release_name(&ms, &(*ctx)->name);
 159         if ((*ctx)->oid != GSS_C_NO_OID) {
 160                 xfree((*ctx)->oid->elements);
 161                 xfree((*ctx)->oid);
 162                 (*ctx)->oid = GSS_C_NO_OID;
 163         }
 164         if ((*ctx)->creds != GSS_C_NO_CREDENTIAL)
 165                 gss_release_cred(&ms, &(*ctx)->creds);
 166         if ((*ctx)->client != GSS_C_NO_NAME)
 167                 gss_release_name(&ms, &(*ctx)->client);
 168         if ((*ctx)->client_creds != GSS_C_NO_CREDENTIAL)
 169                 gss_release_cred(&ms, &(*ctx)->client_creds);
 170
 171         xfree(*ctx);
 172         *ctx = NULL;
 173 }
 174
 175 /*
 176  * Wrapper to init_sec_context
 177  * Requires that the context contains:
 178  *      oid
 179  *      server name (from ssh_gssapi_import_name)
 180  */
 181 OM_uint32
 182 ssh_gssapi_init_ctx(Gssctxt *ctx, int deleg_creds, gss_buffer_desc *recv_tok,
 183     gss_buffer_desc* send_tok, OM_uint32 *flags)
 184 {
 185         int deleg_flag = 0;
 186
 187         if (deleg_creds) {
 188                 deleg_flag = GSS_C_DELEG_FLAG;
 189                 debug("Delegating credentials");
 190         }
 191
 192         ctx->major = gss_init_sec_context(&ctx->minor,
 193             GSS_C_NO_CREDENTIAL, &ctx->context, ctx->name, ctx->oid,
 194             GSS_C_MUTUAL_FLAG | GSS_C_INTEG_FLAG | deleg_flag,
 195             0, NULL, recv_tok, NULL, send_tok, flags, NULL);
 196
 197         if (GSS_ERROR(ctx->major))
 198                 ssh_gssapi_error(ctx);
 199
 200         return (ctx->major);
 201 }
 202
 203 /* Create a service name for the given host */
 204 OM_uint32
 205 ssh_gssapi_import_name(Gssctxt *ctx, const char *host)
 206 {
 207         gss_buffer_desc gssbuf;
 208
 209         gssbuf.length = sizeof("host@") + strlen(host);
 210         gssbuf.value = xmalloc(gssbuf.length);
 211         snprintf(gssbuf.value, gssbuf.length, "host@%s", host);
 212
 213         if ((ctx->major = gss_import_name(&ctx->minor,
 214             &gssbuf, GSS_C_NT_HOSTBASED_SERVICE, &ctx->name)))
 215                 ssh_gssapi_error(ctx);
 216
 217         xfree(gssbuf.value);
 218         return (ctx->major);
 219 }
 220
 221 /* Acquire credentials for a server running on the current host.
 222  * Requires that the context structure contains a valid OID
 223  */
 224
 225 /* Returns a GSSAPI error code */
 226 OM_uint32
 227 ssh_gssapi_acquire_cred(Gssctxt *ctx)
 228 {
 229         OM_uint32 status;
 230         char lname[MAXHOSTNAMELEN];
 231         gss_OID_set oidset;
 232
 233         gss_create_empty_oid_set(&status, &oidset);
 234         gss_add_oid_set_member(&status, ctx->oid, &oidset);
 235
 236         if (gethostname(lname, MAXHOSTNAMELEN))
 237                 return (-1);
 238
 239         if (GSS_ERROR(ssh_gssapi_import_name(ctx, lname)))
 240                 return (ctx->major);
 241
 242         if ((ctx->major = gss_acquire_cred(&ctx->minor,
 243             ctx->name, 0, oidset, GSS_C_ACCEPT, &ctx->creds, NULL, NULL)))
 244                 ssh_gssapi_error(ctx);
 245
 246         gss_release_oid_set(&status, &oidset);
 247         return (ctx->major);
 248 }
 249
 250 OM_uint32
 251 ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash)
 252 {
 253         if ((ctx->major = gss_get_mic(&ctx->minor, ctx->context,
 254             GSS_C_QOP_DEFAULT, buffer, hash)))
 255                 ssh_gssapi_error(ctx);
 256
 257         return (ctx->major);
 258 }
 259
 260 void
 261 ssh_gssapi_buildmic(Buffer *b, const char *user, const char *service,
 262     const char *context)
 263 {
 264         buffer_init(b);
 265         buffer_put_string(b, session_id2, session_id2_len);
 266         buffer_put_char(b, SSH2_MSG_USERAUTH_REQUEST);
 267         buffer_put_cstring(b, user);
 268         buffer_put_cstring(b, service);
 269         buffer_put_cstring(b, context);
 270 }
 271
 272 OM_uint32
 273 ssh_gssapi_server_ctx(Gssctxt **ctx, gss_OID oid) {
 274         if (*ctx)
 275                 ssh_gssapi_delete_ctx(ctx);
 276         ssh_gssapi_build_ctx(ctx);
 277         ssh_gssapi_set_oid(*ctx, oid);
 278         return (ssh_gssapi_acquire_cred(*ctx));
 279 }
 280
 281 #endif /* GSSAPI */