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 40 static OM_uint32 41 parse_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 } 99 100 static gss_OID_desc krb5_mechanism = 101 {9, (void *)(uintptr_t) "\x2a\x86\x48\x86\xf7\x12\x01\x02\x02"}; 102 static gss_OID_desc ntlm_mechanism = 103 {10, (void *)(uintptr_t) "\x2b\x06\x01\x04\x01\x82\x37\x02\x02\x0a"}; 104 static gss_OID_desc spnego_mechanism = 105 {6, (void *)(uintptr_t) "\x2b\x06\x01\x05\x05\x02"}; 106 107 static OM_uint32 108 choose_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 } 148 149 OM_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; 168 169 *minor_status = 0; 170 if (src_name) 171 *src_name = GSS_C_NO_NAME; 172 if (mech_type) 173 *mech_type = GSS_C_NO_OID; 174 if (ret_flags) 175 *ret_flags = 0; 176 if (time_rec) 177 *time_rec = 0; 178 if (delegated_cred_handle) 179 *delegated_cred_handle = GSS_C_NO_CREDENTIAL; 180 _gss_buffer_zero(output_token); 181 182 /* 183 * If this is the first call (*context_handle is NULL), we must 184 * parse the input token to figure out the mechanism to use. 185 */ 186 if (*context_handle == GSS_C_NO_CONTEXT) { 187 gss_OID_desc mech_oid; 188 189 major_status = choose_mech(input_token, &mech_oid); 190 if (major_status != GSS_S_COMPLETE) 191 return (major_status); 192 193 /* 194 * Now that we have a mechanism, we can find the 195 * implementation. 196 */ 197 ctx = malloc(sizeof(struct _gss_context)); 198 if (!ctx) { 199 *minor_status = ENOMEM; 200 return (GSS_S_DEFECTIVE_TOKEN); 201 } 202 memset(ctx, 0, sizeof(struct _gss_context)); 203 m = ctx->gc_mech = _gss_find_mech_switch(&mech_oid); 204 if (!m) { 205 free(ctx); 206 return (GSS_S_BAD_MECH); 207 } 208 } else 209 m = ctx->gc_mech; 210 211 if (cred) { 212 SLIST_FOREACH(mc, &cred->gc_mc, gmc_link) 213 if (mc->gmc_mech == m) 214 break; 215 if (!mc) 216 return (GSS_S_BAD_MECH); 217 acceptor_mc = mc->gmc_cred; 218 } else { 219 acceptor_mc = GSS_C_NO_CREDENTIAL; 220 } 221 delegated_mc = GSS_C_NO_CREDENTIAL; 222 223 mech_ret_flags = 0; 224 major_status = m->gm_accept_sec_context(minor_status, 225 &ctx->gc_ctx, 226 acceptor_mc, 227 input_token, 228 input_chan_bindings, 229 &src_mn, 230 mech_type, 231 output_token, 232 &mech_ret_flags, 233 time_rec, 234 &delegated_mc); 235 if (major_status != GSS_S_COMPLETE && 236 major_status != GSS_S_CONTINUE_NEEDED) { 237 _gss_mg_error(m, major_status, *minor_status); 238 return (major_status); 239 } 240 241 if (src_name && src_mn) { 242 /* 243 * Make a new name and mark it as an MN. 244 */ 245 struct _gss_name *name = _gss_make_name(m, src_mn); 246 247 if (!name) { 248 m->gm_release_name(minor_status, &src_mn); 249 return (GSS_S_FAILURE); 250 } 251 *src_name = (gss_name_t) name; 252 } else if (src_mn) { 253 m->gm_release_name(minor_status, &src_mn); 254 } 255 256 if (delegated_mc == GSS_C_NO_CREDENTIAL) 257 mech_ret_flags &= ~GSS_C_DELEG_FLAG; 258 259 if (mech_ret_flags & GSS_C_DELEG_FLAG) { 260 if (!delegated_cred_handle) { 261 m->gm_release_cred(minor_status, &delegated_mc); 262 mech_ret_flags &= ~GSS_C_DELEG_FLAG; 263 } else { 264 struct _gss_cred *dcred; 265 struct _gss_mechanism_cred *dmc; 266 267 dcred = malloc(sizeof(struct _gss_cred)); 268 if (!dcred) { 269 *minor_status = ENOMEM; 270 return (GSS_S_FAILURE); 271 } 272 SLIST_INIT(&dcred->gc_mc); 273 dmc = malloc(sizeof(struct _gss_mechanism_cred)); 274 if (!dmc) { 275 free(dcred); 276 *minor_status = ENOMEM; 277 return (GSS_S_FAILURE); 278 } 279 dmc->gmc_mech = m; 280 dmc->gmc_mech_oid = &m->gm_mech_oid; 281 dmc->gmc_cred = delegated_mc; 282 SLIST_INSERT_HEAD(&dcred->gc_mc, dmc, gmc_link); 283 284 *delegated_cred_handle = (gss_cred_id_t) dcred; 285 } 286 } 287 288 if (ret_flags) 289 *ret_flags = mech_ret_flags; 290 *context_handle = (gss_ctx_id_t) ctx; 291 return (major_status); 292 } 293