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" 30RCSID("$Id: gss_accept_sec_context.c,v 1.1.1.1 2011/06/10 09:34:42 andrew Exp $"); 31 32static OM_uint32 33parse_header(const gss_buffer_t input_token, gss_OID mech_oid) 34{ 35 unsigned char *p = input_token->value; 36 size_t len = input_token->length; 37 size_t a, b; 38 39 /* 40 * Token must start with [APPLICATION 0] SEQUENCE. 41 * But if it doesn't assume it is DCE-STYLE Kerberos! 42 */ 43 if (len == 0) 44 return (GSS_S_DEFECTIVE_TOKEN); 45 46 p++; 47 len--; 48 49 /* 50 * Decode the length and make sure it agrees with the 51 * token length. 52 */ 53 if (len == 0) 54 return (GSS_S_DEFECTIVE_TOKEN); 55 if ((*p & 0x80) == 0) { 56 a = *p; 57 p++; 58 len--; 59 } else { 60 b = *p & 0x7f; 61 p++; 62 len--; 63 if (len < b) 64 return (GSS_S_DEFECTIVE_TOKEN); 65 a = 0; 66 while (b) { 67 a = (a << 8) | *p; 68 p++; 69 len--; 70 b--; 71 } 72 } 73 if (a != len) 74 return (GSS_S_DEFECTIVE_TOKEN); 75 76 /* 77 * Decode the OID for the mechanism. Simplify life by 78 * assuming that the OID length is less than 128 bytes. 79 */ 80 if (len < 2 || *p != 0x06) 81 return (GSS_S_DEFECTIVE_TOKEN); 82 if ((p[1] & 0x80) || p[1] > (len - 2)) 83 return (GSS_S_DEFECTIVE_TOKEN); 84 mech_oid->length = p[1]; 85 p += 2; 86 len -= 2; 87 mech_oid->elements = p; 88 89 return GSS_S_COMPLETE; 90} 91 92static gss_OID_desc krb5_mechanism = 93 {9, rk_UNCONST("\x2a\x86\x48\x86\xf7\x12\x01\x02\x02")}; 94static gss_OID_desc ntlm_mechanism = 95 {10, rk_UNCONST("\x2b\x06\x01\x04\x01\x82\x37\x02\x02\x0a")}; 96static gss_OID_desc spnego_mechanism = 97 {6, rk_UNCONST("\x2b\x06\x01\x05\x05\x02")}; 98 99static OM_uint32 100choose_mech(const gss_buffer_t input, gss_OID mech_oid) 101{ 102 OM_uint32 status; 103 104 /* 105 * First try to parse the gssapi token header and see if it's a 106 * correct header, use that in the first hand. 107 */ 108 109 status = parse_header(input, mech_oid); 110 if (status == GSS_S_COMPLETE) 111 return GSS_S_COMPLETE; 112 113 /* 114 * Lets guess what mech is really is, callback function to mech ?? 115 */ 116 117 if (input->length > 8 && 118 memcmp((const char *)input->value, "NTLMSSP\x00", 8) == 0) 119 { 120 *mech_oid = ntlm_mechanism; 121 return GSS_S_COMPLETE; 122 } else if (input->length != 0 && 123 ((const char *)input->value)[0] == 0x6E) 124 { 125 /* Could be a raw AP-REQ (check for APPLICATION tag) */ 126 *mech_oid = krb5_mechanism; 127 return GSS_S_COMPLETE; 128 } else if (input->length == 0) { 129 /* 130 * There is the a wierd mode of SPNEGO (in CIFS and 131 * SASL GSS-SPENGO where the first token is zero 132 * length and the acceptor returns a mech_list, lets 133 * hope that is what is happening now. 134 * 135 * http://msdn.microsoft.com/en-us/library/cc213114.aspx 136 * "NegTokenInit2 Variation for Server-Initiation" 137 */ 138 *mech_oid = spnego_mechanism; 139 return GSS_S_COMPLETE; 140 } 141 return status; 142} 143 144 145OM_uint32 gss_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; 164 165 *minor_status = 0; 166 if (src_name) 167 *src_name = GSS_C_NO_NAME; 168 if (mech_type) 169 *mech_type = GSS_C_NO_OID; 170 if (ret_flags) 171 *ret_flags = 0; 172 if (time_rec) 173 *time_rec = 0; 174 if (delegated_cred_handle) 175 *delegated_cred_handle = GSS_C_NO_CREDENTIAL; 176 _mg_buffer_zero(output_token); 177 178 179 /* 180 * If this is the first call (*context_handle is NULL), we must 181 * parse the input token to figure out the mechanism to use. 182 */ 183 if (*context_handle == GSS_C_NO_CONTEXT) { 184 gss_OID_desc mech_oid; 185 186 major_status = choose_mech(input_token, &mech_oid); 187 if (major_status != GSS_S_COMPLETE) 188 return major_status; 189 190 /* 191 * Now that we have a mechanism, we can find the 192 * implementation. 193 */ 194 ctx = malloc(sizeof(struct _gss_context)); 195 if (!ctx) { 196 *minor_status = ENOMEM; 197 return (GSS_S_DEFECTIVE_TOKEN); 198 } 199 memset(ctx, 0, sizeof(struct _gss_context)); 200 m = ctx->gc_mech = __gss_get_mechanism(&mech_oid); 201 if (!m) { 202 free(ctx); 203 return (GSS_S_BAD_MECH); 204 } 205 *context_handle = (gss_ctx_id_t) ctx; 206 } else { 207 m = ctx->gc_mech; 208 } 209 210 if (cred) { 211 SLIST_FOREACH(mc, &cred->gc_mc, gmc_link) 212 if (mc->gmc_mech == m) 213 break; 214 if (!mc) { 215 gss_delete_sec_context(&junk, context_handle, NULL); 216 return (GSS_S_BAD_MECH); 217 } 218 acceptor_mc = mc->gmc_cred; 219 } else { 220 acceptor_mc = GSS_C_NO_CREDENTIAL; 221 } 222 delegated_mc = GSS_C_NO_CREDENTIAL; 223 224 mech_ret_flags = 0; 225 major_status = m->gm_accept_sec_context(minor_status, 226 &ctx->gc_ctx, 227 acceptor_mc, 228 input_token, 229 input_chan_bindings, 230 &src_mn, 231 mech_type, 232 output_token, 233 &mech_ret_flags, 234 time_rec, 235 &delegated_mc); 236 if (major_status != GSS_S_COMPLETE && 237 major_status != GSS_S_CONTINUE_NEEDED) 238 { 239 _gss_mg_error(m, major_status, *minor_status); 240 gss_delete_sec_context(&junk, context_handle, NULL); 241 return (major_status); 242 } 243 244 if (src_name && src_mn) { 245 /* 246 * Make a new name and mark it as an MN. 247 */ 248 struct _gss_name *name = _gss_make_name(m, src_mn); 249 250 if (!name) { 251 m->gm_release_name(minor_status, &src_mn); 252 gss_delete_sec_context(&junk, context_handle, NULL); 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 (mech_ret_flags & GSS_C_DELEG_FLAG) { 261 if (!delegated_cred_handle) { 262 m->gm_release_cred(minor_status, &delegated_mc); 263 if (ret_flags) 264 *ret_flags &= ~GSS_C_DELEG_FLAG; 265 } else if (delegated_mc) { 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 gss_delete_sec_context(&junk, context_handle, NULL); 273 return (GSS_S_FAILURE); 274 } 275 SLIST_INIT(&dcred->gc_mc); 276 dmc = malloc(sizeof(struct _gss_mechanism_cred)); 277 if (!dmc) { 278 free(dcred); 279 *minor_status = ENOMEM; 280 gss_delete_sec_context(&junk, context_handle, NULL); 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 return (major_status); 295} 296