1/*************************************************************************** 2 * _ _ ____ _ 3 * Project ___| | | | _ \| | 4 * / __| | | | |_) | | 5 * | (__| |_| | _ <| |___ 6 * \___|\___/|_| \_\_____| 7 * 8 * Copyright (C) Steve Holme, <steve_holme@hotmail.com>. 9 * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al. 10 * 11 * This software is licensed as described in the file COPYING, which 12 * you should have received as part of this distribution. The terms 13 * are also available at https://curl.se/docs/copyright.html. 14 * 15 * You may opt to use, copy, modify, merge, publish, distribute and/or sell 16 * copies of the Software, and permit persons to whom the Software is 17 * furnished to do so, under the terms of the COPYING file. 18 * 19 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY 20 * KIND, either express or implied. 21 * 22 * SPDX-License-Identifier: curl 23 * 24 * RFC4752 The Kerberos V5 ("GSSAPI") SASL Mechanism 25 * 26 ***************************************************************************/ 27 28#include "curl_setup.h" 29 30#if defined(HAVE_GSSAPI) && defined(USE_KERBEROS5) 31 32#include <curl/curl.h> 33 34#include "vauth/vauth.h" 35#include "curl_sasl.h" 36#include "urldata.h" 37#include "curl_gssapi.h" 38#include "sendf.h" 39#include "curl_printf.h" 40 41/* The last #include files should be: */ 42#include "curl_memory.h" 43#include "memdebug.h" 44 45/* 46 * Curl_auth_is_gssapi_supported() 47 * 48 * This is used to evaluate if GSSAPI (Kerberos V5) is supported. 49 * 50 * Parameters: None 51 * 52 * Returns TRUE if Kerberos V5 is supported by the GSS-API library. 53 */ 54bool Curl_auth_is_gssapi_supported(void) 55{ 56 return TRUE; 57} 58 59/* 60 * Curl_auth_create_gssapi_user_message() 61 * 62 * This is used to generate an already encoded GSSAPI (Kerberos V5) user token 63 * message ready for sending to the recipient. 64 * 65 * Parameters: 66 * 67 * data [in] - The session handle. 68 * userp [in] - The user name. 69 * passwdp [in] - The user's password. 70 * service [in] - The service type such as http, smtp, pop or imap. 71 * host [in[ - The host name. 72 * mutual_auth [in] - Flag specifying whether or not mutual authentication 73 * is enabled. 74 * chlg [in] - Optional challenge message. 75 * krb5 [in/out] - The Kerberos 5 data struct being used and modified. 76 * out [out] - The result storage. 77 * 78 * Returns CURLE_OK on success. 79 */ 80CURLcode Curl_auth_create_gssapi_user_message(struct Curl_easy *data, 81 const char *userp, 82 const char *passwdp, 83 const char *service, 84 const char *host, 85 const bool mutual_auth, 86 const struct bufref *chlg, 87 struct kerberos5data *krb5, 88 struct bufref *out) 89{ 90 CURLcode result = CURLE_OK; 91 OM_uint32 major_status; 92 OM_uint32 minor_status; 93 OM_uint32 unused_status; 94 gss_buffer_desc spn_token = GSS_C_EMPTY_BUFFER; 95 gss_buffer_desc input_token = GSS_C_EMPTY_BUFFER; 96 gss_buffer_desc output_token = GSS_C_EMPTY_BUFFER; 97 98 (void) userp; 99 (void) passwdp; 100 101 if(!krb5->spn) { 102 /* Generate our SPN */ 103 char *spn = Curl_auth_build_spn(service, NULL, host); 104 if(!spn) 105 return CURLE_OUT_OF_MEMORY; 106 107 /* Populate the SPN structure */ 108 spn_token.value = spn; 109 spn_token.length = strlen(spn); 110 111 /* Import the SPN */ 112 major_status = gss_import_name(&minor_status, &spn_token, 113 GSS_C_NT_HOSTBASED_SERVICE, &krb5->spn); 114 if(GSS_ERROR(major_status)) { 115 Curl_gss_log_error(data, "gss_import_name() failed: ", 116 major_status, minor_status); 117 118 free(spn); 119 120 return CURLE_AUTH_ERROR; 121 } 122 123 free(spn); 124 } 125 126 if(chlg) { 127 if(!Curl_bufref_len(chlg)) { 128 infof(data, "GSSAPI handshake failure (empty challenge message)"); 129 return CURLE_BAD_CONTENT_ENCODING; 130 } 131 input_token.value = (void *) Curl_bufref_ptr(chlg); 132 input_token.length = Curl_bufref_len(chlg); 133 } 134 135 major_status = Curl_gss_init_sec_context(data, 136 &minor_status, 137 &krb5->context, 138 krb5->spn, 139 &Curl_krb5_mech_oid, 140 GSS_C_NO_CHANNEL_BINDINGS, 141 &input_token, 142 &output_token, 143 mutual_auth, 144 NULL); 145 146 if(GSS_ERROR(major_status)) { 147 if(output_token.value) 148 gss_release_buffer(&unused_status, &output_token); 149 150 Curl_gss_log_error(data, "gss_init_sec_context() failed: ", 151 major_status, minor_status); 152 153 return CURLE_AUTH_ERROR; 154 } 155 156 if(output_token.value && output_token.length) { 157 result = Curl_bufref_memdup(out, output_token.value, output_token.length); 158 gss_release_buffer(&unused_status, &output_token); 159 } 160 else 161 Curl_bufref_set(out, mutual_auth? "": NULL, 0, NULL); 162 163 return result; 164} 165 166/* 167 * Curl_auth_create_gssapi_security_message() 168 * 169 * This is used to generate an already encoded GSSAPI (Kerberos V5) security 170 * token message ready for sending to the recipient. 171 * 172 * Parameters: 173 * 174 * data [in] - The session handle. 175 * authzid [in] - The authorization identity if some. 176 * chlg [in] - Optional challenge message. 177 * krb5 [in/out] - The Kerberos 5 data struct being used and modified. 178 * out [out] - The result storage. 179 * 180 * Returns CURLE_OK on success. 181 */ 182CURLcode Curl_auth_create_gssapi_security_message(struct Curl_easy *data, 183 const char *authzid, 184 const struct bufref *chlg, 185 struct kerberos5data *krb5, 186 struct bufref *out) 187{ 188 CURLcode result = CURLE_OK; 189 size_t messagelen = 0; 190 unsigned char *message = NULL; 191 OM_uint32 major_status; 192 OM_uint32 minor_status; 193 OM_uint32 unused_status; 194 gss_buffer_desc input_token = GSS_C_EMPTY_BUFFER; 195 gss_buffer_desc output_token = GSS_C_EMPTY_BUFFER; 196 unsigned char *indata; 197 gss_qop_t qop = GSS_C_QOP_DEFAULT; 198 unsigned int sec_layer = 0; 199 unsigned int max_size = 0; 200 201 /* Ensure we have a valid challenge message */ 202 if(!Curl_bufref_len(chlg)) { 203 infof(data, "GSSAPI handshake failure (empty security message)"); 204 return CURLE_BAD_CONTENT_ENCODING; 205 } 206 207 /* Setup the challenge "input" security buffer */ 208 input_token.value = (void *) Curl_bufref_ptr(chlg); 209 input_token.length = Curl_bufref_len(chlg); 210 211 /* Decrypt the inbound challenge and obtain the qop */ 212 major_status = gss_unwrap(&minor_status, krb5->context, &input_token, 213 &output_token, NULL, &qop); 214 if(GSS_ERROR(major_status)) { 215 Curl_gss_log_error(data, "gss_unwrap() failed: ", 216 major_status, minor_status); 217 return CURLE_BAD_CONTENT_ENCODING; 218 } 219 220 /* Not 4 octets long so fail as per RFC4752 Section 3.1 */ 221 if(output_token.length != 4) { 222 infof(data, "GSSAPI handshake failure (invalid security data)"); 223 return CURLE_BAD_CONTENT_ENCODING; 224 } 225 226 /* Extract the security layer and the maximum message size */ 227 indata = output_token.value; 228 sec_layer = indata[0]; 229 max_size = ((unsigned int)indata[1] << 16) | 230 ((unsigned int)indata[2] << 8) | indata[3]; 231 232 /* Free the challenge as it is not required anymore */ 233 gss_release_buffer(&unused_status, &output_token); 234 235 /* Process the security layer */ 236 if(!(sec_layer & GSSAUTH_P_NONE)) { 237 infof(data, "GSSAPI handshake failure (invalid security layer)"); 238 239 return CURLE_BAD_CONTENT_ENCODING; 240 } 241 sec_layer &= GSSAUTH_P_NONE; /* We do not support a security layer */ 242 243 /* Process the maximum message size the server can receive */ 244 if(max_size > 0) { 245 /* The server has told us it supports a maximum receive buffer, however, as 246 we don't require one unless we are encrypting data, we tell the server 247 our receive buffer is zero. */ 248 max_size = 0; 249 } 250 251 /* Allocate our message */ 252 messagelen = 4; 253 if(authzid) 254 messagelen += strlen(authzid); 255 message = malloc(messagelen); 256 if(!message) 257 return CURLE_OUT_OF_MEMORY; 258 259 /* Populate the message with the security layer and client supported receive 260 message size. */ 261 message[0] = sec_layer & 0xFF; 262 message[1] = (max_size >> 16) & 0xFF; 263 message[2] = (max_size >> 8) & 0xFF; 264 message[3] = max_size & 0xFF; 265 266 /* If given, append the authorization identity. */ 267 268 if(authzid && *authzid) 269 memcpy(message + 4, authzid, messagelen - 4); 270 271 /* Setup the "authentication data" security buffer */ 272 input_token.value = message; 273 input_token.length = messagelen; 274 275 /* Encrypt the data */ 276 major_status = gss_wrap(&minor_status, krb5->context, 0, 277 GSS_C_QOP_DEFAULT, &input_token, NULL, 278 &output_token); 279 if(GSS_ERROR(major_status)) { 280 Curl_gss_log_error(data, "gss_wrap() failed: ", 281 major_status, minor_status); 282 free(message); 283 return CURLE_AUTH_ERROR; 284 } 285 286 /* Return the response. */ 287 result = Curl_bufref_memdup(out, output_token.value, output_token.length); 288 /* Free the output buffer */ 289 gss_release_buffer(&unused_status, &output_token); 290 291 /* Free the message buffer */ 292 free(message); 293 294 return result; 295} 296 297/* 298 * Curl_auth_cleanup_gssapi() 299 * 300 * This is used to clean up the GSSAPI (Kerberos V5) specific data. 301 * 302 * Parameters: 303 * 304 * krb5 [in/out] - The Kerberos 5 data struct being cleaned up. 305 * 306 */ 307void Curl_auth_cleanup_gssapi(struct kerberos5data *krb5) 308{ 309 OM_uint32 minor_status; 310 311 /* Free our security context */ 312 if(krb5->context != GSS_C_NO_CONTEXT) { 313 gss_delete_sec_context(&minor_status, &krb5->context, GSS_C_NO_BUFFER); 314 krb5->context = GSS_C_NO_CONTEXT; 315 } 316 317 /* Free the SPN */ 318 if(krb5->spn != GSS_C_NO_NAME) { 319 gss_release_name(&minor_status, &krb5->spn); 320 krb5->spn = GSS_C_NO_NAME; 321 } 322} 323 324#endif /* HAVE_GSSAPI && USE_KERBEROS5 */ 325