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curl/lib/vauth/spnego_sspi.c
georgeok a730432e59
spnego_sspi: add support for channel binding
Attempt to add support for Secure Channel binding when negotiate
authentication is used. The problem to solve is that by default IIS
accepts channel binding and curl doesn't utilise them. The result was a
401 response. Scope affects only the Schannel(winssl)-SSPI combination.

Fixes https://github.com/curl/curl/issues/3503
Closes https://github.com/curl/curl/pull/3509
2019-02-01 09:56:27 +01:00

348 lines
11 KiB
C

/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
* are also available at https://curl.haxx.se/docs/copyright.html.
*
* You may opt to use, copy, modify, merge, publish, distribute and/or sell
* copies of the Software, and permit persons to whom the Software is
* furnished to do so, under the terms of the COPYING file.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
* RFC4178 Simple and Protected GSS-API Negotiation Mechanism
*
***************************************************************************/
#include "curl_setup.h"
#if defined(USE_WINDOWS_SSPI) && defined(USE_SPNEGO)
#include <curl/curl.h>
#include "vauth/vauth.h"
#include "urldata.h"
#include "curl_base64.h"
#include "warnless.h"
#include "curl_multibyte.h"
#include "sendf.h"
#include "strerror.h"
/* The last #include files should be: */
#include "curl_memory.h"
#include "memdebug.h"
/*
* Curl_auth_is_spnego_supported()
*
* This is used to evaluate if SPNEGO (Negotiate) is supported.
*
* Parameters: None
*
* Returns TRUE if Negotiate is supported by Windows SSPI.
*/
bool Curl_auth_is_spnego_supported(void)
{
PSecPkgInfo SecurityPackage;
SECURITY_STATUS status;
/* Query the security package for Negotiate */
status = s_pSecFn->QuerySecurityPackageInfo((TCHAR *)
TEXT(SP_NAME_NEGOTIATE),
&SecurityPackage);
return (status == SEC_E_OK ? TRUE : FALSE);
}
/*
* Curl_auth_decode_spnego_message()
*
* This is used to decode an already encoded SPNEGO (Negotiate) challenge
* message.
*
* Parameters:
*
* data [in] - The session handle.
* user [in] - The user name in the format User or Domain\User.
* password [in] - The user's password.
* service [in] - The service type such as http, smtp, pop or imap.
* host [in] - The host name.
* chlg64 [in] - The optional base64 encoded challenge message.
* nego [in/out] - The Negotiate data struct being used and modified.
*
* Returns CURLE_OK on success.
*/
CURLcode Curl_auth_decode_spnego_message(struct Curl_easy *data,
const char *user,
const char *password,
const char *service,
const char *host,
const char *chlg64,
struct negotiatedata *nego)
{
CURLcode result = CURLE_OK;
size_t chlglen = 0;
unsigned char *chlg = NULL;
PSecPkgInfo SecurityPackage;
SecBuffer chlg_buf[2];
SecBuffer resp_buf;
SecBufferDesc chlg_desc;
SecBufferDesc resp_desc;
unsigned long attrs;
TimeStamp expiry; /* For Windows 9x compatibility of SSPI calls */
#if defined(CURL_DISABLE_VERBOSE_STRINGS)
(void) data;
#endif
if(nego->context && nego->status == SEC_E_OK) {
/* We finished successfully our part of authentication, but server
* rejected it (since we're again here). Exit with an error since we
* can't invent anything better */
Curl_auth_spnego_cleanup(nego);
return CURLE_LOGIN_DENIED;
}
if(!nego->spn) {
/* Generate our SPN */
nego->spn = Curl_auth_build_spn(service, host, NULL);
if(!nego->spn)
return CURLE_OUT_OF_MEMORY;
}
if(!nego->output_token) {
/* Query the security package for Negotiate */
nego->status = s_pSecFn->QuerySecurityPackageInfo((TCHAR *)
TEXT(SP_NAME_NEGOTIATE),
&SecurityPackage);
if(nego->status != SEC_E_OK)
return CURLE_NOT_BUILT_IN;
nego->token_max = SecurityPackage->cbMaxToken;
/* Release the package buffer as it is not required anymore */
s_pSecFn->FreeContextBuffer(SecurityPackage);
/* Allocate our output buffer */
nego->output_token = malloc(nego->token_max);
if(!nego->output_token)
return CURLE_OUT_OF_MEMORY;
}
if(!nego->credentials) {
/* Do we have credentials to use or are we using single sign-on? */
if(user && *user) {
/* Populate our identity structure */
result = Curl_create_sspi_identity(user, password, &nego->identity);
if(result)
return result;
/* Allow proper cleanup of the identity structure */
nego->p_identity = &nego->identity;
}
else
/* Use the current Windows user */
nego->p_identity = NULL;
/* Allocate our credentials handle */
nego->credentials = calloc(1, sizeof(CredHandle));
if(!nego->credentials)
return CURLE_OUT_OF_MEMORY;
/* Acquire our credentials handle */
nego->status =
s_pSecFn->AcquireCredentialsHandle(NULL,
(TCHAR *)TEXT(SP_NAME_NEGOTIATE),
SECPKG_CRED_OUTBOUND, NULL,
nego->p_identity, NULL, NULL,
nego->credentials, &expiry);
if(nego->status != SEC_E_OK)
return CURLE_LOGIN_DENIED;
/* Allocate our new context handle */
nego->context = calloc(1, sizeof(CtxtHandle));
if(!nego->context)
return CURLE_OUT_OF_MEMORY;
}
if(chlg64 && *chlg64) {
/* Decode the base-64 encoded challenge message */
if(*chlg64 != '=') {
result = Curl_base64_decode(chlg64, &chlg, &chlglen);
if(result)
return result;
}
/* Ensure we have a valid challenge message */
if(!chlg) {
infof(data, "SPNEGO handshake failure (empty challenge message)\n");
return CURLE_BAD_CONTENT_ENCODING;
}
/* Setup the challenge "input" security buffer */
chlg_desc.ulVersion = SECBUFFER_VERSION;
chlg_desc.cBuffers = 1;
chlg_desc.pBuffers = &chlg_buf[0];
chlg_buf[0].BufferType = SECBUFFER_TOKEN;
chlg_buf[0].pvBuffer = chlg;
chlg_buf[0].cbBuffer = curlx_uztoul(chlglen);
#ifdef SECPKG_ATTR_ENDPOINT_BINDINGS
/* ssl context comes from Schannel.
* When extended protection is used in IIS server,
* we have to pass a second SecBuffer to the SecBufferDesc
* otherwise IIS will not pass the authentication (401 response).
* Minimum supported version is Windows 7.
* https://docs.microsoft.com/en-us/security-updates
* /SecurityAdvisories/2009/973811
*/
if(nego->sslContext) {
SEC_CHANNEL_BINDINGS channelBindings;
SecPkgContext_Bindings pkgBindings;
pkgBindings.Bindings = &channelBindings;
nego->status = s_pSecFn->QueryContextAttributes(
nego->sslContext,
SECPKG_ATTR_ENDPOINT_BINDINGS,
&pkgBindings
);
if(nego->status == SEC_E_OK) {
chlg_desc.cBuffers++;
chlg_buf[1].BufferType = SECBUFFER_CHANNEL_BINDINGS;
chlg_buf[1].cbBuffer = pkgBindings.BindingsLength;
chlg_buf[1].pvBuffer = pkgBindings.Bindings;
}
}
#endif
}
/* Setup the response "output" security buffer */
resp_desc.ulVersion = SECBUFFER_VERSION;
resp_desc.cBuffers = 1;
resp_desc.pBuffers = &resp_buf;
resp_buf.BufferType = SECBUFFER_TOKEN;
resp_buf.pvBuffer = nego->output_token;
resp_buf.cbBuffer = curlx_uztoul(nego->token_max);
/* Generate our challenge-response message */
nego->status = s_pSecFn->InitializeSecurityContext(nego->credentials,
chlg ? nego->context :
NULL,
nego->spn,
ISC_REQ_CONFIDENTIALITY,
0, SECURITY_NATIVE_DREP,
chlg ? &chlg_desc : NULL,
0, nego->context,
&resp_desc, &attrs,
&expiry);
/* Free the decoded challenge as it is not required anymore */
free(chlg);
if(GSS_ERROR(nego->status)) {
failf(data, "InitializeSecurityContext failed: %s",
Curl_sspi_strerror(data->conn, nego->status));
return CURLE_OUT_OF_MEMORY;
}
if(nego->status == SEC_I_COMPLETE_NEEDED ||
nego->status == SEC_I_COMPLETE_AND_CONTINUE) {
nego->status = s_pSecFn->CompleteAuthToken(nego->context, &resp_desc);
if(GSS_ERROR(nego->status)) {
return CURLE_RECV_ERROR;
}
}
nego->output_token_length = resp_buf.cbBuffer;
return result;
}
/*
* Curl_auth_create_spnego_message()
*
* This is used to generate an already encoded SPNEGO (Negotiate) response
* message ready for sending to the recipient.
*
* Parameters:
*
* data [in] - The session handle.
* nego [in/out] - The Negotiate data struct being used and modified.
* outptr [in/out] - The address where a pointer to newly allocated memory
* holding the result will be stored upon completion.
* outlen [out] - The length of the output message.
*
* Returns CURLE_OK on success.
*/
CURLcode Curl_auth_create_spnego_message(struct Curl_easy *data,
struct negotiatedata *nego,
char **outptr, size_t *outlen)
{
CURLcode result;
/* Base64 encode the already generated response */
result = Curl_base64_encode(data,
(const char *) nego->output_token,
nego->output_token_length,
outptr, outlen);
if(result)
return result;
if(!*outptr || !*outlen) {
free(*outptr);
return CURLE_REMOTE_ACCESS_DENIED;
}
return CURLE_OK;
}
/*
* Curl_auth_spnego_cleanup()
*
* This is used to clean up the SPNEGO (Negotiate) specific data.
*
* Parameters:
*
* nego [in/out] - The Negotiate data struct being cleaned up.
*
*/
void Curl_auth_spnego_cleanup(struct negotiatedata *nego)
{
/* Free our security context */
if(nego->context) {
s_pSecFn->DeleteSecurityContext(nego->context);
free(nego->context);
nego->context = NULL;
}
/* Free our credentials handle */
if(nego->credentials) {
s_pSecFn->FreeCredentialsHandle(nego->credentials);
free(nego->credentials);
nego->credentials = NULL;
}
/* Free our identity */
Curl_sspi_free_identity(nego->p_identity);
nego->p_identity = NULL;
/* Free the SPN and output token */
Curl_safefree(nego->spn);
Curl_safefree(nego->output_token);
/* Reset any variables */
nego->status = 0;
nego->token_max = 0;
}
#endif /* USE_WINDOWS_SSPI && USE_SPNEGO */