Damien Miller | d783435 | 2006-08-05 12:39:39 +1000 | [diff] [blame^] | 1 | /* $OpenBSD: gss-serv.c,v 1.20 2006/08/03 03:34:42 deraadt Exp $ */ |
Darren Tucker | 0efd155 | 2003-08-26 11:49:55 +1000 | [diff] [blame] | 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 | |
Damien Miller | d783435 | 2006-08-05 12:39:39 +1000 | [diff] [blame^] | 31 | #include <sys/types.h> |
| 32 | |
Damien Miller | e3476ed | 2006-07-24 14:13:33 +1000 | [diff] [blame] | 33 | #include <string.h> |
Damien Miller | b8fe89c | 2006-07-24 14:51:00 +1000 | [diff] [blame] | 34 | #include <unistd.h> |
Damien Miller | e3476ed | 2006-07-24 14:13:33 +1000 | [diff] [blame] | 35 | |
Damien Miller | d783435 | 2006-08-05 12:39:39 +1000 | [diff] [blame^] | 36 | #include "xmalloc.h" |
| 37 | #include "buffer.h" |
| 38 | #include "key.h" |
| 39 | #include "hostfile.h" |
Darren Tucker | 0efd155 | 2003-08-26 11:49:55 +1000 | [diff] [blame] | 40 | #include "auth.h" |
| 41 | #include "log.h" |
| 42 | #include "channels.h" |
| 43 | #include "session.h" |
Damien Miller | 3f94188 | 2006-03-31 23:13:02 +1100 | [diff] [blame] | 44 | #include "misc.h" |
Darren Tucker | 0efd155 | 2003-08-26 11:49:55 +1000 | [diff] [blame] | 45 | |
| 46 | #include "ssh-gss.h" |
| 47 | |
Darren Tucker | 0efd155 | 2003-08-26 11:49:55 +1000 | [diff] [blame] | 48 | static ssh_gssapi_client gssapi_client = |
| 49 | { GSS_C_EMPTY_BUFFER, GSS_C_EMPTY_BUFFER, |
| 50 | GSS_C_NO_CREDENTIAL, NULL, {NULL, NULL, NULL}}; |
| 51 | |
| 52 | ssh_gssapi_mech gssapi_null_mech = |
| 53 | { NULL, NULL, {0, NULL}, NULL, NULL, NULL, NULL}; |
| 54 | |
| 55 | #ifdef KRB5 |
| 56 | extern ssh_gssapi_mech gssapi_kerberos_mech; |
| 57 | #endif |
| 58 | |
| 59 | ssh_gssapi_mech* supported_mechs[]= { |
| 60 | #ifdef KRB5 |
| 61 | &gssapi_kerberos_mech, |
| 62 | #endif |
| 63 | &gssapi_null_mech, |
| 64 | }; |
| 65 | |
Damien Miller | 9fac263 | 2005-11-05 15:03:48 +1100 | [diff] [blame] | 66 | /* Unprivileged */ |
Darren Tucker | 0efd155 | 2003-08-26 11:49:55 +1000 | [diff] [blame] | 67 | void |
| 68 | ssh_gssapi_supported_oids(gss_OID_set *oidset) |
| 69 | { |
| 70 | int i = 0; |
| 71 | OM_uint32 min_status; |
| 72 | int present; |
| 73 | gss_OID_set supported; |
| 74 | |
| 75 | gss_create_empty_oid_set(&min_status, oidset); |
| 76 | gss_indicate_mechs(&min_status, &supported); |
| 77 | |
| 78 | while (supported_mechs[i]->name != NULL) { |
| 79 | if (GSS_ERROR(gss_test_oid_set_member(&min_status, |
| 80 | &supported_mechs[i]->oid, supported, &present))) |
| 81 | present = 0; |
| 82 | if (present) |
| 83 | gss_add_oid_set_member(&min_status, |
| 84 | &supported_mechs[i]->oid, oidset); |
| 85 | i++; |
| 86 | } |
Damien Miller | 91a2d97 | 2006-03-26 00:05:44 +1100 | [diff] [blame] | 87 | |
| 88 | gss_release_oid_set(&min_status, &supported); |
Darren Tucker | 0efd155 | 2003-08-26 11:49:55 +1000 | [diff] [blame] | 89 | } |
| 90 | |
| 91 | |
| 92 | /* Wrapper around accept_sec_context |
| 93 | * Requires that the context contains: |
| 94 | * oid |
| 95 | * credentials (from ssh_gssapi_acquire_cred) |
| 96 | */ |
Damien Miller | 9fac263 | 2005-11-05 15:03:48 +1100 | [diff] [blame] | 97 | /* Privileged */ |
Darren Tucker | 0efd155 | 2003-08-26 11:49:55 +1000 | [diff] [blame] | 98 | OM_uint32 |
| 99 | ssh_gssapi_accept_ctx(Gssctxt *ctx, gss_buffer_desc *recv_tok, |
| 100 | gss_buffer_desc *send_tok, OM_uint32 *flags) |
| 101 | { |
| 102 | OM_uint32 status; |
| 103 | gss_OID mech; |
| 104 | |
| 105 | ctx->major = gss_accept_sec_context(&ctx->minor, |
| 106 | &ctx->context, ctx->creds, recv_tok, |
| 107 | GSS_C_NO_CHANNEL_BINDINGS, &ctx->client, &mech, |
| 108 | send_tok, flags, NULL, &ctx->client_creds); |
| 109 | |
| 110 | if (GSS_ERROR(ctx->major)) |
| 111 | ssh_gssapi_error(ctx); |
| 112 | |
| 113 | if (ctx->client_creds) |
| 114 | debug("Received some client credentials"); |
| 115 | else |
| 116 | debug("Got no client credentials"); |
| 117 | |
| 118 | status = ctx->major; |
| 119 | |
| 120 | /* Now, if we're complete and we have the right flags, then |
| 121 | * we flag the user as also having been authenticated |
| 122 | */ |
| 123 | |
| 124 | if (((flags == NULL) || ((*flags & GSS_C_MUTUAL_FLAG) && |
| 125 | (*flags & GSS_C_INTEG_FLAG))) && (ctx->major == GSS_S_COMPLETE)) { |
| 126 | if (ssh_gssapi_getclient(ctx, &gssapi_client)) |
| 127 | fatal("Couldn't convert client name"); |
| 128 | } |
| 129 | |
| 130 | return (status); |
| 131 | } |
| 132 | |
| 133 | /* |
| 134 | * This parses an exported name, extracting the mechanism specific portion |
| 135 | * to use for ACL checking. It verifies that the name belongs the mechanism |
| 136 | * originally selected. |
| 137 | */ |
| 138 | static OM_uint32 |
| 139 | ssh_gssapi_parse_ename(Gssctxt *ctx, gss_buffer_t ename, gss_buffer_t name) |
| 140 | { |
Damien Miller | eccb9de | 2005-06-17 12:59:34 +1000 | [diff] [blame] | 141 | u_char *tok; |
Darren Tucker | 0efd155 | 2003-08-26 11:49:55 +1000 | [diff] [blame] | 142 | OM_uint32 offset; |
| 143 | OM_uint32 oidl; |
Damien Miller | 134350c | 2003-09-02 22:56:42 +1000 | [diff] [blame] | 144 | |
Damien Miller | 6fd6def | 2005-11-05 15:07:05 +1100 | [diff] [blame] | 145 | tok = ename->value; |
Damien Miller | 134350c | 2003-09-02 22:56:42 +1000 | [diff] [blame] | 146 | |
| 147 | /* |
| 148 | * Check that ename is long enough for all of the fixed length |
Darren Tucker | 0efd155 | 2003-08-26 11:49:55 +1000 | [diff] [blame] | 149 | * header, and that the initial ID bytes are correct |
| 150 | */ |
| 151 | |
Damien Miller | 6fd6def | 2005-11-05 15:07:05 +1100 | [diff] [blame] | 152 | if (ename->length < 6 || memcmp(tok, "\x04\x01", 2) != 0) |
Darren Tucker | 0efd155 | 2003-08-26 11:49:55 +1000 | [diff] [blame] | 153 | return GSS_S_FAILURE; |
| 154 | |
| 155 | /* |
| 156 | * Extract the OID, and check it. Here GSSAPI breaks with tradition |
| 157 | * and does use the OID type and length bytes. To confuse things |
| 158 | * there are two lengths - the first including these, and the |
| 159 | * second without. |
| 160 | */ |
| 161 | |
Damien Miller | 3f94188 | 2006-03-31 23:13:02 +1100 | [diff] [blame] | 162 | oidl = get_u16(tok+2); /* length including next two bytes */ |
Darren Tucker | 0efd155 | 2003-08-26 11:49:55 +1000 | [diff] [blame] | 163 | oidl = oidl-2; /* turn it into the _real_ length of the variable OID */ |
| 164 | |
| 165 | /* |
| 166 | * Check the BER encoding for correct type and length, that the |
| 167 | * string is long enough and that the OID matches that in our context |
| 168 | */ |
| 169 | if (tok[4] != 0x06 || tok[5] != oidl || |
Damien Miller | 134350c | 2003-09-02 22:56:42 +1000 | [diff] [blame] | 170 | ename->length < oidl+6 || |
Damien Miller | 6fd6def | 2005-11-05 15:07:05 +1100 | [diff] [blame] | 171 | !ssh_gssapi_check_oid(ctx, tok+6, oidl)) |
Darren Tucker | 0efd155 | 2003-08-26 11:49:55 +1000 | [diff] [blame] | 172 | return GSS_S_FAILURE; |
| 173 | |
| 174 | offset = oidl+6; |
Damien Miller | 134350c | 2003-09-02 22:56:42 +1000 | [diff] [blame] | 175 | |
Darren Tucker | 0efd155 | 2003-08-26 11:49:55 +1000 | [diff] [blame] | 176 | if (ename->length < offset+4) |
| 177 | return GSS_S_FAILURE; |
Damien Miller | 134350c | 2003-09-02 22:56:42 +1000 | [diff] [blame] | 178 | |
Damien Miller | 3f94188 | 2006-03-31 23:13:02 +1100 | [diff] [blame] | 179 | name->length = get_u32(tok+offset); |
Darren Tucker | 0efd155 | 2003-08-26 11:49:55 +1000 | [diff] [blame] | 180 | offset += 4; |
Damien Miller | 134350c | 2003-09-02 22:56:42 +1000 | [diff] [blame] | 181 | |
Darren Tucker | 0efd155 | 2003-08-26 11:49:55 +1000 | [diff] [blame] | 182 | if (ename->length < offset+name->length) |
Damien Miller | 134350c | 2003-09-02 22:56:42 +1000 | [diff] [blame] | 183 | return GSS_S_FAILURE; |
| 184 | |
Damien Miller | a0c4ad2 | 2003-09-02 22:56:18 +1000 | [diff] [blame] | 185 | name->value = xmalloc(name->length+1); |
Damien Miller | 0b70b54 | 2006-03-15 11:20:03 +1100 | [diff] [blame] | 186 | memcpy(name->value, tok+offset, name->length); |
Damien Miller | a0c4ad2 | 2003-09-02 22:56:18 +1000 | [diff] [blame] | 187 | ((char *)name->value)[name->length] = 0; |
| 188 | |
Darren Tucker | 0efd155 | 2003-08-26 11:49:55 +1000 | [diff] [blame] | 189 | return GSS_S_COMPLETE; |
Damien Miller | 134350c | 2003-09-02 22:56:42 +1000 | [diff] [blame] | 190 | } |
Darren Tucker | 0efd155 | 2003-08-26 11:49:55 +1000 | [diff] [blame] | 191 | |
| 192 | /* Extract the client details from a given context. This can only reliably |
| 193 | * be called once for a context */ |
| 194 | |
Damien Miller | 9fac263 | 2005-11-05 15:03:48 +1100 | [diff] [blame] | 195 | /* Privileged (called from accept_secure_ctx) */ |
Darren Tucker | 0efd155 | 2003-08-26 11:49:55 +1000 | [diff] [blame] | 196 | OM_uint32 |
| 197 | ssh_gssapi_getclient(Gssctxt *ctx, ssh_gssapi_client *client) |
| 198 | { |
| 199 | int i = 0; |
| 200 | |
| 201 | gss_buffer_desc ename; |
Damien Miller | 134350c | 2003-09-02 22:56:42 +1000 | [diff] [blame] | 202 | |
Darren Tucker | 0efd155 | 2003-08-26 11:49:55 +1000 | [diff] [blame] | 203 | client->mech = NULL; |
| 204 | |
| 205 | while (supported_mechs[i]->name != NULL) { |
| 206 | if (supported_mechs[i]->oid.length == ctx->oid->length && |
| 207 | (memcmp(supported_mechs[i]->oid.elements, |
| 208 | ctx->oid->elements, ctx->oid->length) == 0)) |
| 209 | client->mech = supported_mechs[i]; |
| 210 | i++; |
| 211 | } |
| 212 | |
Damien Miller | 134350c | 2003-09-02 22:56:42 +1000 | [diff] [blame] | 213 | if (client->mech == NULL) |
Darren Tucker | 0efd155 | 2003-08-26 11:49:55 +1000 | [diff] [blame] | 214 | return GSS_S_FAILURE; |
Damien Miller | 134350c | 2003-09-02 22:56:42 +1000 | [diff] [blame] | 215 | |
| 216 | if ((ctx->major = gss_display_name(&ctx->minor, ctx->client, |
Darren Tucker | 0efd155 | 2003-08-26 11:49:55 +1000 | [diff] [blame] | 217 | &client->displayname, NULL))) { |
Damien Miller | 134350c | 2003-09-02 22:56:42 +1000 | [diff] [blame] | 218 | ssh_gssapi_error(ctx); |
| 219 | return (ctx->major); |
Darren Tucker | 0efd155 | 2003-08-26 11:49:55 +1000 | [diff] [blame] | 220 | } |
Damien Miller | 134350c | 2003-09-02 22:56:42 +1000 | [diff] [blame] | 221 | |
| 222 | if ((ctx->major = gss_export_name(&ctx->minor, ctx->client, |
Darren Tucker | 0efd155 | 2003-08-26 11:49:55 +1000 | [diff] [blame] | 223 | &ename))) { |
| 224 | ssh_gssapi_error(ctx); |
| 225 | return (ctx->major); |
| 226 | } |
Damien Miller | 134350c | 2003-09-02 22:56:42 +1000 | [diff] [blame] | 227 | |
Darren Tucker | 0efd155 | 2003-08-26 11:49:55 +1000 | [diff] [blame] | 228 | if ((ctx->major = ssh_gssapi_parse_ename(ctx,&ename, |
| 229 | &client->exportedname))) { |
| 230 | return (ctx->major); |
| 231 | } |
| 232 | |
| 233 | /* We can't copy this structure, so we just move the pointer to it */ |
| 234 | client->creds = ctx->client_creds; |
| 235 | ctx->client_creds = GSS_C_NO_CREDENTIAL; |
| 236 | return (ctx->major); |
| 237 | } |
| 238 | |
Darren Tucker | 3e33cec | 2003-10-02 16:12:36 +1000 | [diff] [blame] | 239 | /* As user - called on fatal/exit */ |
Darren Tucker | 0efd155 | 2003-08-26 11:49:55 +1000 | [diff] [blame] | 240 | void |
Darren Tucker | 3e33cec | 2003-10-02 16:12:36 +1000 | [diff] [blame] | 241 | ssh_gssapi_cleanup_creds(void) |
Darren Tucker | 0efd155 | 2003-08-26 11:49:55 +1000 | [diff] [blame] | 242 | { |
| 243 | if (gssapi_client.store.filename != NULL) { |
| 244 | /* Unlink probably isn't sufficient */ |
Damien Miller | 0b70b54 | 2006-03-15 11:20:03 +1100 | [diff] [blame] | 245 | debug("removing gssapi cred file\"%s\"", |
| 246 | gssapi_client.store.filename); |
Darren Tucker | 0efd155 | 2003-08-26 11:49:55 +1000 | [diff] [blame] | 247 | unlink(gssapi_client.store.filename); |
| 248 | } |
| 249 | } |
| 250 | |
| 251 | /* As user */ |
| 252 | void |
| 253 | ssh_gssapi_storecreds(void) |
| 254 | { |
| 255 | if (gssapi_client.mech && gssapi_client.mech->storecreds) { |
| 256 | (*gssapi_client.mech->storecreds)(&gssapi_client); |
Darren Tucker | 0efd155 | 2003-08-26 11:49:55 +1000 | [diff] [blame] | 257 | } else |
| 258 | debug("ssh_gssapi_storecreds: Not a GSSAPI mechanism"); |
| 259 | } |
| 260 | |
| 261 | /* This allows GSSAPI methods to do things to the childs environment based |
| 262 | * on the passed authentication process and credentials. |
| 263 | */ |
| 264 | /* As user */ |
| 265 | void |
| 266 | ssh_gssapi_do_child(char ***envp, u_int *envsizep) |
| 267 | { |
| 268 | |
| 269 | if (gssapi_client.store.envvar != NULL && |
| 270 | gssapi_client.store.envval != NULL) { |
Darren Tucker | 0efd155 | 2003-08-26 11:49:55 +1000 | [diff] [blame] | 271 | debug("Setting %s to %s", gssapi_client.store.envvar, |
Damien Miller | 6fd6def | 2005-11-05 15:07:05 +1100 | [diff] [blame] | 272 | gssapi_client.store.envval); |
Darren Tucker | 0efd155 | 2003-08-26 11:49:55 +1000 | [diff] [blame] | 273 | child_set_env(envp, envsizep, gssapi_client.store.envvar, |
Damien Miller | 0dc1bef | 2005-07-17 17:22:45 +1000 | [diff] [blame] | 274 | gssapi_client.store.envval); |
Darren Tucker | 0efd155 | 2003-08-26 11:49:55 +1000 | [diff] [blame] | 275 | } |
| 276 | } |
| 277 | |
Darren Tucker | 8813bbb | 2005-10-03 18:17:02 +1000 | [diff] [blame] | 278 | /* Privileged */ |
Darren Tucker | 0efd155 | 2003-08-26 11:49:55 +1000 | [diff] [blame] | 279 | int |
| 280 | ssh_gssapi_userok(char *user) |
| 281 | { |
Damien Miller | da9984f | 2005-08-31 19:46:26 +1000 | [diff] [blame] | 282 | OM_uint32 lmin; |
| 283 | |
Darren Tucker | 0efd155 | 2003-08-26 11:49:55 +1000 | [diff] [blame] | 284 | if (gssapi_client.exportedname.length == 0 || |
| 285 | gssapi_client.exportedname.value == NULL) { |
| 286 | debug("No suitable client data"); |
| 287 | return 0; |
| 288 | } |
| 289 | if (gssapi_client.mech && gssapi_client.mech->userok) |
Damien Miller | da9984f | 2005-08-31 19:46:26 +1000 | [diff] [blame] | 290 | if ((*gssapi_client.mech->userok)(&gssapi_client, user)) |
| 291 | return 1; |
| 292 | else { |
| 293 | /* Destroy delegated credentials if userok fails */ |
| 294 | gss_release_buffer(&lmin, &gssapi_client.displayname); |
| 295 | gss_release_buffer(&lmin, &gssapi_client.exportedname); |
| 296 | gss_release_cred(&lmin, &gssapi_client.creds); |
| 297 | memset(&gssapi_client, 0, sizeof(ssh_gssapi_client)); |
| 298 | return 0; |
| 299 | } |
Darren Tucker | 0efd155 | 2003-08-26 11:49:55 +1000 | [diff] [blame] | 300 | else |
| 301 | debug("ssh_gssapi_userok: Unknown GSSAPI mechanism"); |
| 302 | return (0); |
| 303 | } |
| 304 | |
Damien Miller | 9fac263 | 2005-11-05 15:03:48 +1100 | [diff] [blame] | 305 | /* Privileged */ |
Damien Miller | 0425d40 | 2003-11-17 22:18:21 +1100 | [diff] [blame] | 306 | OM_uint32 |
| 307 | ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic) |
| 308 | { |
| 309 | ctx->major = gss_verify_mic(&ctx->minor, ctx->context, |
| 310 | gssbuf, gssmic, NULL); |
| 311 | |
| 312 | return (ctx->major); |
| 313 | } |
| 314 | |
Darren Tucker | 0efd155 | 2003-08-26 11:49:55 +1000 | [diff] [blame] | 315 | #endif |