1/*- 2 * Copyright (c) 2005 Doug Rabson 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * $FreeBSD$ 27 */ 28 29#include <gssapi/gssapi.h> 30#include <stdlib.h> 31#include <string.h> 32#include <errno.h> 33 34#include "mech_switch.h" 35#include "context.h" 36#include "cred.h" 37#include "name.h" 38#include "utils.h" 39 40static OM_uint32 41parse_header(const gss_buffer_t input_token, gss_OID mech_oid) 42{ 43 unsigned char *p = input_token->value; 44 size_t len = input_token->length; 45 size_t a, b; 46 47 /* 48 * Token must start with [APPLICATION 0] SEQUENCE. 49 * But if it doesn't assume it is DCE-STYLE Kerberos! 50 */ 51 if (len == 0) 52 return (GSS_S_DEFECTIVE_TOKEN); 53 54 p++; 55 len--; 56 57 /* 58 * Decode the length and make sure it agrees with the 59 * token length. 60 */ 61 if (len == 0) 62 return (GSS_S_DEFECTIVE_TOKEN); 63 if ((*p & 0x80) == 0) { 64 a = *p; 65 p++; 66 len--; 67 } else { 68 b = *p & 0x7f; 69 p++; 70 len--; 71 if (len < b) 72 return (GSS_S_DEFECTIVE_TOKEN); 73 a = 0; 74 while (b) { 75 a = (a << 8) | *p; 76 p++; 77 len--; 78 b--; 79 } 80 } 81 if (a != len) 82 return (GSS_S_DEFECTIVE_TOKEN); 83 84 /* 85 * Decode the OID for the mechanism. Simplify life by 86 * assuming that the OID length is less than 128 bytes. 87 */ 88 if (len < 2 || *p != 0x06) 89 return (GSS_S_DEFECTIVE_TOKEN); 90 if ((p[1] & 0x80) || p[1] > (len - 2)) 91 return (GSS_S_DEFECTIVE_TOKEN); 92 mech_oid->length = p[1]; 93 p += 2; 94 len -= 2; 95 mech_oid->elements = p; 96 97 return (GSS_S_COMPLETE); 98} 99 100static gss_OID_desc krb5_mechanism = 101{9, (void *)(uintptr_t) "\x2a\x86\x48\x86\xf7\x12\x01\x02\x02"}; 102static gss_OID_desc ntlm_mechanism = 103{10, (void *)(uintptr_t) "\x2b\x06\x01\x04\x01\x82\x37\x02\x02\x0a"}; 104static gss_OID_desc spnego_mechanism = 105{6, (void *)(uintptr_t) "\x2b\x06\x01\x05\x05\x02"}; 106 107static OM_uint32 108choose_mech(const gss_buffer_t input, gss_OID mech_oid) 109{ 110 OM_uint32 status; 111 112 /* 113 * First try to parse the gssapi token header and see if it's a 114 * correct header, use that in the first hand. 115 */ 116 117 status = parse_header(input, mech_oid); 118 if (status == GSS_S_COMPLETE) 119 return (GSS_S_COMPLETE); 120 121 /* 122 * Lets guess what mech is really is, callback function to mech ?? 123 */ 124 125 if (input->length > 8 && 126 memcmp((const char *)input->value, "NTLMSSP\x00", 8) == 0) 127 { 128 *mech_oid = ntlm_mechanism; 129 return (GSS_S_COMPLETE); 130 } else if (input->length != 0 && 131 ((const char *)input->value)[0] == 0x6E) 132 { 133 /* Could be a raw AP-REQ (check for APPLICATION tag) */ 134 *mech_oid = krb5_mechanism; 135 return (GSS_S_COMPLETE); 136 } else if (input->length == 0) { 137 /* 138 * There is the a wierd mode of SPNEGO (in CIFS and 139 * SASL GSS-SPENGO where the first token is zero 140 * length and the acceptor returns a mech_list, lets 141 * hope that is what is happening now. 142 */ 143 *mech_oid = spnego_mechanism; 144 return (GSS_S_COMPLETE); 145 } 146 return (status); 147} 148 149OM_uint32 gss_accept_sec_context(OM_uint32 *minor_status, 150 gss_ctx_id_t *context_handle, 151 const gss_cred_id_t acceptor_cred_handle, 152 const gss_buffer_t input_token, 153 const gss_channel_bindings_t input_chan_bindings, 154 gss_name_t *src_name, 155 gss_OID *mech_type, 156 gss_buffer_t output_token, 157 OM_uint32 *ret_flags, 158 OM_uint32 *time_rec, 159 gss_cred_id_t *delegated_cred_handle) 160{ 161 OM_uint32 major_status, mech_ret_flags; 162 struct _gss_mech_switch *m; 163 struct _gss_context *ctx = (struct _gss_context *) *context_handle; 164 struct _gss_cred *cred = (struct _gss_cred *) acceptor_cred_handle; 165 struct _gss_mechanism_cred *mc; 166 gss_cred_id_t acceptor_mc, delegated_mc; 167 gss_name_t src_mn; 168 int allocated_ctx; 169 170 *minor_status = 0; 171 if (src_name) 172 *src_name = GSS_C_NO_NAME; 173 if (mech_type) 174 *mech_type = GSS_C_NO_OID; 175 if (ret_flags) 176 *ret_flags = 0; 177 if (time_rec) 178 *time_rec = 0; 179 if (delegated_cred_handle) 180 *delegated_cred_handle = GSS_C_NO_CREDENTIAL; 181 _gss_buffer_zero(output_token); 182 183 /* 184 * If this is the first call (*context_handle is NULL), we must 185 * parse the input token to figure out the mechanism to use. 186 */ 187 if (*context_handle == GSS_C_NO_CONTEXT) { 188 gss_OID_desc mech_oid; 189 190 major_status = choose_mech(input_token, &mech_oid); 191 if (major_status != GSS_S_COMPLETE) 192 return (major_status); 193 194 /* 195 * Now that we have a mechanism, we can find the 196 * implementation. 197 */ 198 ctx = malloc(sizeof(struct _gss_context)); 199 if (!ctx) { 200 *minor_status = ENOMEM; 201 return (GSS_S_DEFECTIVE_TOKEN); 202 } 203 memset(ctx, 0, sizeof(struct _gss_context)); 204 m = ctx->gc_mech = _gss_find_mech_switch(&mech_oid); 205 if (!m) { 206 free(ctx); 207 return (GSS_S_BAD_MECH); 208 } 209 allocated_ctx = 1; 210 } else { 211 m = ctx->gc_mech; 212 allocated_ctx = 0; 213 } 214 215 if (cred) { 216 SLIST_FOREACH(mc, &cred->gc_mc, gmc_link) 217 if (mc->gmc_mech == m) 218 break; 219 if (!mc) 220 return (GSS_S_BAD_MECH); 221 acceptor_mc = mc->gmc_cred; 222 } else { 223 acceptor_mc = GSS_C_NO_CREDENTIAL; 224 } 225 delegated_mc = GSS_C_NO_CREDENTIAL; 226 227 mech_ret_flags = 0; 228 major_status = m->gm_accept_sec_context(minor_status, 229 &ctx->gc_ctx, 230 acceptor_mc, 231 input_token, 232 input_chan_bindings, 233 &src_mn, 234 mech_type, 235 output_token, 236 &mech_ret_flags, 237 time_rec, 238 &delegated_mc); 239 if (major_status != GSS_S_COMPLETE && 240 major_status != GSS_S_CONTINUE_NEEDED) { 241 _gss_mg_error(m, major_status, *minor_status); 242 return (major_status); 243 } 244 245 if (src_name && src_mn) { 246 /* 247 * Make a new name and mark it as an MN. 248 */ 249 struct _gss_name *name = _gss_make_name(m, src_mn); 250 251 if (!name) { 252 m->gm_release_name(minor_status, &src_mn); 253 return (GSS_S_FAILURE); 254 } 255 *src_name = (gss_name_t) name; 256 } else if (src_mn) { 257 m->gm_release_name(minor_status, &src_mn); 258 } 259 260 if (delegated_mc == GSS_C_NO_CREDENTIAL) 261 mech_ret_flags &= ~GSS_C_DELEG_FLAG; 262 263 if (mech_ret_flags & GSS_C_DELEG_FLAG) { 264 if (!delegated_cred_handle) { 265 m->gm_release_cred(minor_status, &delegated_mc); 266 mech_ret_flags &= ~GSS_C_DELEG_FLAG; 267 } else { 268 struct _gss_cred *dcred; 269 struct _gss_mechanism_cred *dmc; 270 271 dcred = malloc(sizeof(struct _gss_cred)); 272 if (!dcred) { 273 *minor_status = ENOMEM; 274 return (GSS_S_FAILURE); 275 } 276 SLIST_INIT(&dcred->gc_mc); 277 dmc = malloc(sizeof(struct _gss_mechanism_cred)); 278 if (!dmc) { 279 free(dcred); 280 *minor_status = ENOMEM; 281 return (GSS_S_FAILURE); 282 } 283 dmc->gmc_mech = m; 284 dmc->gmc_mech_oid = &m->gm_mech_oid; 285 dmc->gmc_cred = delegated_mc; 286 SLIST_INSERT_HEAD(&dcred->gc_mc, dmc, gmc_link); 287 288 *delegated_cred_handle = (gss_cred_id_t) dcred; 289 } 290 } 291 292 if (ret_flags) 293 *ret_flags = mech_ret_flags; 294 *context_handle = (gss_ctx_id_t) ctx; 295 return (major_status); 296} 297