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: src/lib/libgssapi/gss_accept_sec_context.c,v 1.1 2005/12/29 14:40:20 dfr Exp $ 27 */ 28 29#include "mech_locl.h" 30 31static OM_uint32 32parse_header(const gss_buffer_t input_token, gss_OID mech_oid) 33{ 34 unsigned char *p = input_token->value; 35 size_t len = input_token->length; 36 size_t a, b; 37 38 /* 39 * Token must start with [APPLICATION 0] SEQUENCE. 40 * But if it doesn't assume it is DCE-STYLE Kerberos! 41 */ 42 if (len == 0) 43 return (GSS_S_DEFECTIVE_TOKEN); 44 45 p++; 46 len--; 47 48 /* 49 * Decode the length and make sure it agrees with the 50 * token length. 51 */ 52 if (len == 0) 53 return (GSS_S_DEFECTIVE_TOKEN); 54 if ((*p & 0x80) == 0) { 55 a = *p; 56 p++; 57 len--; 58 } else { 59 b = *p & 0x7f; 60 p++; 61 len--; 62 if (len < b) 63 return (GSS_S_DEFECTIVE_TOKEN); 64 a = 0; 65 while (b) { 66 a = (a << 8) | *p; 67 p++; 68 len--; 69 b--; 70 } 71 } 72 if (a != len) 73 return (GSS_S_DEFECTIVE_TOKEN); 74 75 /* 76 * Decode the OID for the mechanism. Simplify life by 77 * assuming that the OID length is less than 128 bytes. 78 */ 79 if (len < 2 || *p != 0x06) 80 return (GSS_S_DEFECTIVE_TOKEN); 81 if ((p[1] & 0x80) || p[1] > (len - 2)) 82 return (GSS_S_DEFECTIVE_TOKEN); 83 mech_oid->length = p[1]; 84 p += 2; 85 len -= 2; 86 mech_oid->elements = p; 87 88 return GSS_S_COMPLETE; 89} 90 91static gss_OID_desc krb5_mechanism = 92 {9, rk_UNCONST("\x2a\x86\x48\x86\xf7\x12\x01\x02\x02")}; 93static gss_OID_desc ntlm_mechanism = 94 {10, rk_UNCONST("\x2b\x06\x01\x04\x01\x82\x37\x02\x02\x0a")}; 95static gss_OID_desc spnego_mechanism = 96 {6, rk_UNCONST("\x2b\x06\x01\x05\x05\x02")}; 97 98static OM_uint32 99choose_mech(const gss_buffer_t input, gss_OID mech_oid) 100{ 101 OM_uint32 status; 102 103 /* 104 * First try to parse the gssapi token header and see if it's a 105 * correct header, use that in the first hand. 106 */ 107 108 status = parse_header(input, mech_oid); 109 if (status == GSS_S_COMPLETE) 110 return GSS_S_COMPLETE; 111 112 /* 113 * Lets guess what mech is really is, callback function to mech ?? 114 */ 115 116 if (input->length > 8 && 117 memcmp((const char *)input->value, "NTLMSSP\x00", 8) == 0) 118 { 119 *mech_oid = ntlm_mechanism; 120 return GSS_S_COMPLETE; 121 } else if (input->length != 0 && 122 ((const char *)input->value)[0] == 0x6E) 123 { 124 /* Could be a raw AP-REQ (check for APPLICATION tag) */ 125 *mech_oid = krb5_mechanism; 126 return GSS_S_COMPLETE; 127 } else if (input->length == 0) { 128 /* 129 * There is the a wierd mode of SPNEGO (in CIFS and 130 * SASL GSS-SPENGO where the first token is zero 131 * length and the acceptor returns a mech_list, lets 132 * hope that is what is happening now. 133 * 134 * http://msdn.microsoft.com/en-us/library/cc213114.aspx 135 * "NegTokenInit2 Variation for Server-Initiation" 136 */ 137 *mech_oid = spnego_mechanism; 138 return GSS_S_COMPLETE; 139 } 140 return status; 141} 142 143 144GSSAPI_LIB_FUNCTION OM_uint32 GSSAPI_LIB_CALL 145gss_accept_sec_context(OM_uint32 *minor_status, 146 gss_ctx_id_t *context_handle, 147 const gss_cred_id_t acceptor_cred_handle, 148 const gss_buffer_t input_token, 149 const gss_channel_bindings_t input_chan_bindings, 150 gss_name_t *src_name, 151 gss_OID *mech_type, 152 gss_buffer_t output_token, 153 OM_uint32 *ret_flags, 154 OM_uint32 *time_rec, 155 gss_cred_id_t *delegated_cred_handle) 156{ 157 OM_uint32 major_status, mech_ret_flags, junk; 158 gssapi_mech_interface m; 159 struct _gss_context *ctx = (struct _gss_context *) *context_handle; 160 struct _gss_cred *cred = (struct _gss_cred *) acceptor_cred_handle; 161 struct _gss_mechanism_cred *mc; 162 gss_cred_id_t acceptor_mc, delegated_mc; 163 gss_name_t src_mn; 164 gss_OID mech_ret_type = NULL; 165 166 *minor_status = 0; 167 if (src_name) 168 *src_name = GSS_C_NO_NAME; 169 if (mech_type) 170 *mech_type = GSS_C_NO_OID; 171 if (ret_flags) 172 *ret_flags = 0; 173 if (time_rec) 174 *time_rec = 0; 175 if (delegated_cred_handle) 176 *delegated_cred_handle = GSS_C_NO_CREDENTIAL; 177 _mg_buffer_zero(output_token); 178 179 180 /* 181 * If this is the first call (*context_handle is NULL), we must 182 * parse the input token to figure out the mechanism to use. 183 */ 184 if (*context_handle == GSS_C_NO_CONTEXT) { 185 gss_OID_desc mech_oid; 186 187 major_status = choose_mech(input_token, &mech_oid); 188 if (major_status != GSS_S_COMPLETE) 189 return major_status; 190 191 /* 192 * Now that we have a mechanism, we can find the 193 * implementation. 194 */ 195 ctx = malloc(sizeof(struct _gss_context)); 196 if (!ctx) { 197 *minor_status = ENOMEM; 198 return (GSS_S_DEFECTIVE_TOKEN); 199 } 200 memset(ctx, 0, sizeof(struct _gss_context)); 201 m = ctx->gc_mech = __gss_get_mechanism(&mech_oid); 202 if (!m) { 203 free(ctx); 204 return (GSS_S_BAD_MECH); 205 } 206 *context_handle = (gss_ctx_id_t) ctx; 207 } else { 208 m = ctx->gc_mech; 209 } 210 211 if (cred) { 212 HEIM_SLIST_FOREACH(mc, &cred->gc_mc, gmc_link) 213 if (mc->gmc_mech == m) 214 break; 215 if (!mc) { 216 gss_delete_sec_context(&junk, context_handle, NULL); 217 return (GSS_S_BAD_MECH); 218 } 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_ret_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 { 240 _gss_mg_error(m, major_status, *minor_status); 241 gss_delete_sec_context(&junk, context_handle, NULL); 242 return (major_status); 243 } 244 245 if (mech_type) 246 *mech_type = mech_ret_type; 247 248 if (src_name && src_mn) { 249 /* 250 * Make a new name and mark it as an MN. 251 */ 252 struct _gss_name *name = _gss_make_name(m, src_mn); 253 254 if (!name) { 255 m->gm_release_name(minor_status, &src_mn); 256 gss_delete_sec_context(&junk, context_handle, NULL); 257 return (GSS_S_FAILURE); 258 } 259 *src_name = (gss_name_t) name; 260 } else if (src_mn) { 261 m->gm_release_name(minor_status, &src_mn); 262 } 263 264 if (mech_ret_flags & GSS_C_DELEG_FLAG) { 265 if (!delegated_cred_handle) { 266 m->gm_release_cred(minor_status, &delegated_mc); 267 mech_ret_flags &= 268 ~(GSS_C_DELEG_FLAG|GSS_C_DELEG_POLICY_FLAG); 269 } else if (gss_oid_equal(mech_ret_type, &m->gm_mech_oid) == 0) { 270 /* 271 * If the returned mech_type is not the same 272 * as the mech, assume its pseudo mech type 273 * and the returned type is already a 274 * mech-glue object 275 */ 276 *delegated_cred_handle = delegated_mc; 277 278 } else if (delegated_mc) { 279 struct _gss_cred *dcred; 280 struct _gss_mechanism_cred *dmc; 281 282 dcred = malloc(sizeof(struct _gss_cred)); 283 if (!dcred) { 284 *minor_status = ENOMEM; 285 gss_delete_sec_context(&junk, context_handle, NULL); 286 return (GSS_S_FAILURE); 287 } 288 HEIM_SLIST_INIT(&dcred->gc_mc); 289 dmc = malloc(sizeof(struct _gss_mechanism_cred)); 290 if (!dmc) { 291 free(dcred); 292 *minor_status = ENOMEM; 293 gss_delete_sec_context(&junk, context_handle, NULL); 294 return (GSS_S_FAILURE); 295 } 296 dmc->gmc_mech = m; 297 dmc->gmc_mech_oid = &m->gm_mech_oid; 298 dmc->gmc_cred = delegated_mc; 299 HEIM_SLIST_INSERT_HEAD(&dcred->gc_mc, dmc, gmc_link); 300 301 *delegated_cred_handle = (gss_cred_id_t) dcred; 302 } 303 } 304 305 if (ret_flags) 306 *ret_flags = mech_ret_flags; 307 return (major_status); 308} 309