1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2005 Doug Rabson 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 * 28 * $FreeBSD$ 29 */ 30 31 #include <gssapi/gssapi.h> 32 #include <stdlib.h> 33 #include <string.h> 34 #include <errno.h> 35 36 #include "mech_switch.h" 37 #include "context.h" 38 #include "cred.h" 39 #include "name.h" 40 #include "utils.h" 41 42 static OM_uint32 43 parse_header(const gss_buffer_t input_token, gss_OID mech_oid) 44 { 45 unsigned char *p = input_token->value; 46 size_t len = input_token->length; 47 size_t a, b; 48 49 /* 50 * Token must start with [APPLICATION 0] SEQUENCE. 51 * But if it doesn't assume it is DCE-STYLE Kerberos! 52 */ 53 if (len == 0) 54 return (GSS_S_DEFECTIVE_TOKEN); 55 56 p++; 57 len--; 58 59 /* 60 * Decode the length and make sure it agrees with the 61 * token length. 62 */ 63 if (len == 0) 64 return (GSS_S_DEFECTIVE_TOKEN); 65 if ((*p & 0x80) == 0) { 66 a = *p; 67 p++; 68 len--; 69 } else { 70 b = *p & 0x7f; 71 p++; 72 len--; 73 if (len < b) 74 return (GSS_S_DEFECTIVE_TOKEN); 75 a = 0; 76 while (b) { 77 a = (a << 8) | *p; 78 p++; 79 len--; 80 b--; 81 } 82 } 83 if (a != len) 84 return (GSS_S_DEFECTIVE_TOKEN); 85 86 /* 87 * Decode the OID for the mechanism. Simplify life by 88 * assuming that the OID length is less than 128 bytes. 89 */ 90 if (len < 2 || *p != 0x06) 91 return (GSS_S_DEFECTIVE_TOKEN); 92 if ((p[1] & 0x80) || p[1] > (len - 2)) 93 return (GSS_S_DEFECTIVE_TOKEN); 94 mech_oid->length = p[1]; 95 p += 2; 96 len -= 2; 97 mech_oid->elements = p; 98 99 return (GSS_S_COMPLETE); 100 } 101 102 static gss_OID_desc krb5_mechanism = 103 {9, (void *)(uintptr_t) "\x2a\x86\x48\x86\xf7\x12\x01\x02\x02"}; 104 static gss_OID_desc ntlm_mechanism = 105 {10, (void *)(uintptr_t) "\x2b\x06\x01\x04\x01\x82\x37\x02\x02\x0a"}; 106 static gss_OID_desc spnego_mechanism = 107 {6, (void *)(uintptr_t) "\x2b\x06\x01\x05\x05\x02"}; 108 109 static OM_uint32 110 choose_mech(const gss_buffer_t input, gss_OID mech_oid) 111 { 112 OM_uint32 status; 113 114 /* 115 * First try to parse the gssapi token header and see if it's a 116 * correct header, use that in the first hand. 117 */ 118 119 status = parse_header(input, mech_oid); 120 if (status == GSS_S_COMPLETE) 121 return (GSS_S_COMPLETE); 122 123 /* 124 * Lets guess what mech is really is, callback function to mech ?? 125 */ 126 127 if (input->length > 8 && 128 memcmp((const char *)input->value, "NTLMSSP\x00", 8) == 0) 129 { 130 *mech_oid = ntlm_mechanism; 131 return (GSS_S_COMPLETE); 132 } else if (input->length != 0 && 133 ((const char *)input->value)[0] == 0x6E) 134 { 135 /* Could be a raw AP-REQ (check for APPLICATION tag) */ 136 *mech_oid = krb5_mechanism; 137 return (GSS_S_COMPLETE); 138 } else if (input->length == 0) { 139 /* 140 * There is the a weird mode of SPNEGO (in CIFS and 141 * SASL GSS-SPENGO where the first token is zero 142 * length and the acceptor returns a mech_list, lets 143 * hope that is what is happening now. 144 */ 145 *mech_oid = spnego_mechanism; 146 return (GSS_S_COMPLETE); 147 } 148 return (status); 149 } 150 151 OM_uint32 gss_accept_sec_context(OM_uint32 *minor_status, 152 gss_ctx_id_t *context_handle, 153 const gss_cred_id_t acceptor_cred_handle, 154 const gss_buffer_t input_token, 155 const gss_channel_bindings_t input_chan_bindings, 156 gss_name_t *src_name, 157 gss_OID *mech_type, 158 gss_buffer_t output_token, 159 OM_uint32 *ret_flags, 160 OM_uint32 *time_rec, 161 gss_cred_id_t *delegated_cred_handle) 162 { 163 OM_uint32 major_status, mech_ret_flags; 164 struct _gss_mech_switch *m; 165 struct _gss_context *ctx = (struct _gss_context *) *context_handle; 166 struct _gss_cred *cred = (struct _gss_cred *) acceptor_cred_handle; 167 struct _gss_mechanism_cred *mc; 168 gss_cred_id_t acceptor_mc, delegated_mc; 169 gss_name_t src_mn; 170 171 *minor_status = 0; 172 if (src_name) 173 *src_name = GSS_C_NO_NAME; 174 if (mech_type) 175 *mech_type = GSS_C_NO_OID; 176 if (ret_flags) 177 *ret_flags = 0; 178 if (time_rec) 179 *time_rec = 0; 180 if (delegated_cred_handle) 181 *delegated_cred_handle = GSS_C_NO_CREDENTIAL; 182 _gss_buffer_zero(output_token); 183 184 /* 185 * If this is the first call (*context_handle is NULL), we must 186 * parse the input token to figure out the mechanism to use. 187 */ 188 if (*context_handle == GSS_C_NO_CONTEXT) { 189 gss_OID_desc mech_oid; 190 191 major_status = choose_mech(input_token, &mech_oid); 192 if (major_status != GSS_S_COMPLETE) 193 return (major_status); 194 195 /* 196 * Now that we have a mechanism, we can find the 197 * implementation. 198 */ 199 ctx = malloc(sizeof(struct _gss_context)); 200 if (!ctx) { 201 *minor_status = ENOMEM; 202 return (GSS_S_DEFECTIVE_TOKEN); 203 } 204 memset(ctx, 0, sizeof(struct _gss_context)); 205 m = ctx->gc_mech = _gss_find_mech_switch(&mech_oid); 206 if (!m) { 207 free(ctx); 208 return (GSS_S_BAD_MECH); 209 } 210 } else 211 m = ctx->gc_mech; 212 213 if (cred) { 214 SLIST_FOREACH(mc, &cred->gc_mc, gmc_link) 215 if (mc->gmc_mech == m) 216 break; 217 if (!mc) 218 return (GSS_S_BAD_MECH); 219 acceptor_mc = mc->gmc_cred; 220 } else { 221 acceptor_mc = GSS_C_NO_CREDENTIAL; 222 } 223 delegated_mc = GSS_C_NO_CREDENTIAL; 224 225 mech_ret_flags = 0; 226 major_status = m->gm_accept_sec_context(minor_status, 227 &ctx->gc_ctx, 228 acceptor_mc, 229 input_token, 230 input_chan_bindings, 231 &src_mn, 232 mech_type, 233 output_token, 234 &mech_ret_flags, 235 time_rec, 236 &delegated_mc); 237 if (major_status != GSS_S_COMPLETE && 238 major_status != GSS_S_CONTINUE_NEEDED) { 239 _gss_mg_error(m, major_status, *minor_status); 240 return (major_status); 241 } 242 243 if (src_name && src_mn) { 244 /* 245 * Make a new name and mark it as an MN. 246 */ 247 struct _gss_name *name = _gss_make_name(m, src_mn); 248 249 if (!name) { 250 m->gm_release_name(minor_status, &src_mn); 251 return (GSS_S_FAILURE); 252 } 253 *src_name = (gss_name_t) name; 254 } else if (src_mn) { 255 m->gm_release_name(minor_status, &src_mn); 256 } 257 258 if (delegated_mc == GSS_C_NO_CREDENTIAL) 259 mech_ret_flags &= ~GSS_C_DELEG_FLAG; 260 261 if (mech_ret_flags & GSS_C_DELEG_FLAG) { 262 if (!delegated_cred_handle) { 263 m->gm_release_cred(minor_status, &delegated_mc); 264 mech_ret_flags &= ~GSS_C_DELEG_FLAG; 265 } else { 266 struct _gss_cred *dcred; 267 struct _gss_mechanism_cred *dmc; 268 269 dcred = malloc(sizeof(struct _gss_cred)); 270 if (!dcred) { 271 *minor_status = ENOMEM; 272 return (GSS_S_FAILURE); 273 } 274 SLIST_INIT(&dcred->gc_mc); 275 dmc = malloc(sizeof(struct _gss_mechanism_cred)); 276 if (!dmc) { 277 free(dcred); 278 *minor_status = ENOMEM; 279 return (GSS_S_FAILURE); 280 } 281 dmc->gmc_mech = m; 282 dmc->gmc_mech_oid = &m->gm_mech_oid; 283 dmc->gmc_cred = delegated_mc; 284 SLIST_INSERT_HEAD(&dcred->gc_mc, dmc, gmc_link); 285 286 *delegated_cred_handle = (gss_cred_id_t) dcred; 287 } 288 } 289 290 if (ret_flags) 291 *ret_flags = mech_ret_flags; 292 *context_handle = (gss_ctx_id_t) ctx; 293 return (major_status); 294 } 295