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94400f32e9
curl/lib/vauth/krb5_sspi.c
Daniel Gustafsson 94400f32e9 all: Refactor malloc+memset to use calloc 
When a zeroed out allocation is required, use calloc() rather than
malloc() followed by an explicit memset(). The result will be the
same, but using calloc() everywhere increases consistency in the
codebase and avoids the risk of subtle bugs when code is injected
between malloc and memset by accident.

Closes https://github.com/curl/curl/pull/2497
2018-04-15 03:00:37 -04:00

515 lines
16 KiB
C
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/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 2014 - 2017, Steve Holme, <steve_holme@hotmail.com>.
*
* 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.
*
* RFC4752 The Kerberos V5 ("GSSAPI") SASL Mechanism
*
***************************************************************************/
#include "curl_setup.h"
#if defined(USE_WINDOWS_SSPI) && defined(USE_KERBEROS5)
#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"
/* The last #include files should be: */
#include "curl_memory.h"
#include "memdebug.h"
/*
* Curl_auth_is_gssapi_supported()
*
* This is used to evaluate if GSSAPI (Kerberos V5) is supported.
*
* Parameters: None
*
* Returns TRUE if Kerberos V5 is supported by Windows SSPI.
*/
bool Curl_auth_is_gssapi_supported(void)
{
PSecPkgInfo SecurityPackage;
SECURITY_STATUS status;
/* Query the security package for Kerberos */
status = s_pSecFn->QuerySecurityPackageInfo((TCHAR *)
TEXT(SP_NAME_KERBEROS),
&SecurityPackage);
return (status == SEC_E_OK ? TRUE : FALSE);
}
/*
* Curl_auth_create_gssapi_user_message()
*
* This is used to generate an already encoded GSSAPI (Kerberos V5) user token
* message ready for sending to the recipient.
*
* Parameters:
*
* data [in] - The session handle.
* userp [in] - The user name in the format User or Domain\User.
* passdwp [in] - The user's password.
* service [in] - The service type such as http, smtp, pop or imap.
* host [in] - The host name.
* mutual_auth [in] - Flag specifying whether or not mutual authentication
* is enabled.
* chlg64 [in] - The optional base64 encoded challenge message.
* krb5 [in/out] - The Kerberos 5 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_gssapi_user_message(struct Curl_easy *data,
const char *userp,
const char *passwdp,
const char *service,
const char *host,
const bool mutual_auth,
const char *chlg64,
struct kerberos5data *krb5,
char **outptr, size_t *outlen)
{
CURLcode result = CURLE_OK;
size_t chlglen = 0;
unsigned char *chlg = NULL;
CtxtHandle context;
PSecPkgInfo SecurityPackage;
SecBuffer chlg_buf;
SecBuffer resp_buf;
SecBufferDesc chlg_desc;
SecBufferDesc resp_desc;
SECURITY_STATUS status;
unsigned long attrs;
TimeStamp expiry; /* For Windows 9x compatibility of SSPI calls */
if(!krb5->spn) {
/* Generate our SPN */
krb5->spn = Curl_auth_build_spn(service, host, NULL);
if(!krb5->spn)
return CURLE_OUT_OF_MEMORY;
}
if(!krb5->output_token) {
/* Query the security package for Kerberos */
status = s_pSecFn->QuerySecurityPackageInfo((TCHAR *)
TEXT(SP_NAME_KERBEROS),
&SecurityPackage);
if(status != SEC_E_OK) {
return CURLE_NOT_BUILT_IN;
}
krb5->token_max = SecurityPackage->cbMaxToken;
/* Release the package buffer as it is not required anymore */
s_pSecFn->FreeContextBuffer(SecurityPackage);
/* Allocate our response buffer */
krb5->output_token = malloc(krb5->token_max);
if(!krb5->output_token)
return CURLE_OUT_OF_MEMORY;
}
if(!krb5->credentials) {
/* Do we have credientials to use or are we using single sign-on? */
if(userp && *userp) {
/* Populate our identity structure */
result = Curl_create_sspi_identity(userp, passwdp, &krb5->identity);
if(result)
return result;
/* Allow proper cleanup of the identity structure */
krb5->p_identity = &krb5->identity;
}
else
/* Use the current Windows user */
krb5->p_identity = NULL;
/* Allocate our credentials handle */
krb5->credentials = calloc(1, sizeof(CredHandle));
if(!krb5->credentials)
return CURLE_OUT_OF_MEMORY;
/* Acquire our credentials handle */
status = s_pSecFn->AcquireCredentialsHandle(NULL,
(TCHAR *)
TEXT(SP_NAME_KERBEROS),
SECPKG_CRED_OUTBOUND, NULL,
krb5->p_identity, NULL, NULL,
krb5->credentials, &expiry);
if(status != SEC_E_OK)
return CURLE_LOGIN_DENIED;
/* Allocate our new context handle */
krb5->context = calloc(1, sizeof(CtxtHandle));
if(!krb5->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, "GSSAPI 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;
chlg_buf.BufferType = SECBUFFER_TOKEN;
chlg_buf.pvBuffer = chlg;
chlg_buf.cbBuffer = curlx_uztoul(chlglen);
}
/* 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 = krb5->output_token;
resp_buf.cbBuffer = curlx_uztoul(krb5->token_max);
/* Generate our challenge-response message */
status = s_pSecFn->InitializeSecurityContext(krb5->credentials,
chlg ? krb5->context : NULL,
krb5->spn,
(mutual_auth ?
ISC_REQ_MUTUAL_AUTH : 0),
0, SECURITY_NATIVE_DREP,
chlg ? &chlg_desc : NULL, 0,
&context,
&resp_desc, &attrs,
&expiry);
/* Free the decoded challenge as it is not required anymore */
free(chlg);
if(status != SEC_E_OK && status != SEC_I_CONTINUE_NEEDED) {
return CURLE_RECV_ERROR;
}
if(memcmp(&context, krb5->context, sizeof(context))) {
s_pSecFn->DeleteSecurityContext(krb5->context);
memcpy(krb5->context, &context, sizeof(context));
}
if(resp_buf.cbBuffer) {
/* Base64 encode the response */
result = Curl_base64_encode(data, (char *) resp_buf.pvBuffer,
resp_buf.cbBuffer, outptr, outlen);
}
else if(mutual_auth) {
*outptr = strdup("");
if(!*outptr)
result = CURLE_OUT_OF_MEMORY;
}
return result;
}
/*
* Curl_auth_create_gssapi_security_message()
*
* This is used to generate an already encoded GSSAPI (Kerberos V5) security
* token message ready for sending to the recipient.
*
* Parameters:
*
* data [in] - The session handle.
* chlg64 [in] - The optional base64 encoded challenge message.
* krb5 [in/out] - The Kerberos 5 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_gssapi_security_message(struct Curl_easy *data,
const char *chlg64,
struct kerberos5data *krb5,
char **outptr,
size_t *outlen)
{
CURLcode result = CURLE_OK;
size_t offset = 0;
size_t chlglen = 0;
size_t messagelen = 0;
size_t appdatalen = 0;
unsigned char *chlg = NULL;
unsigned char *trailer = NULL;
unsigned char *message = NULL;
unsigned char *padding = NULL;
unsigned char *appdata = NULL;
SecBuffer input_buf[2];
SecBuffer wrap_buf[3];
SecBufferDesc input_desc;
SecBufferDesc wrap_desc;
unsigned long indata = 0;
unsigned long outdata = 0;
unsigned long qop = 0;
unsigned long sec_layer = 0;
unsigned long max_size = 0;
SecPkgContext_Sizes sizes;
SecPkgCredentials_Names names;
SECURITY_STATUS status;
char *user_name;
/* Decode the base-64 encoded input message */
if(strlen(chlg64) && *chlg64 != '=') {
result = Curl_base64_decode(chlg64, &chlg, &chlglen);
if(result)
return result;
}
/* Ensure we have a valid challenge message */
if(!chlg) {
infof(data, "GSSAPI handshake failure (empty security message)\n");
return CURLE_BAD_CONTENT_ENCODING;
}
/* Get our response size information */
status = s_pSecFn->QueryContextAttributes(krb5->context,
SECPKG_ATTR_SIZES,
&sizes);
if(status != SEC_E_OK) {
free(chlg);
return CURLE_OUT_OF_MEMORY;
}
/* Get the fully qualified username back from the context */
status = s_pSecFn->QueryCredentialsAttributes(krb5->credentials,
SECPKG_CRED_ATTR_NAMES,
&names);
if(status != SEC_E_OK) {
free(chlg);
return CURLE_RECV_ERROR;
}
/* Setup the "input" security buffer */
input_desc.ulVersion = SECBUFFER_VERSION;
input_desc.cBuffers = 2;
input_desc.pBuffers = input_buf;
input_buf[0].BufferType = SECBUFFER_STREAM;
input_buf[0].pvBuffer = chlg;
input_buf[0].cbBuffer = curlx_uztoul(chlglen);
input_buf[1].BufferType = SECBUFFER_DATA;
input_buf[1].pvBuffer = NULL;
input_buf[1].cbBuffer = 0;
/* Decrypt the inbound challenge and obtain the qop */
status = s_pSecFn->DecryptMessage(krb5->context, &input_desc, 0, &qop);
if(status != SEC_E_OK) {
infof(data, "GSSAPI handshake failure (empty security message)\n");
free(chlg);
return CURLE_BAD_CONTENT_ENCODING;
}
/* Not 4 octets long so fail as per RFC4752 Section 3.1 */
if(input_buf[1].cbBuffer != 4) {
infof(data, "GSSAPI handshake failure (invalid security data)\n");
free(chlg);
return CURLE_BAD_CONTENT_ENCODING;
}
/* Copy the data out and free the challenge as it is not required anymore */
memcpy(&indata, input_buf[1].pvBuffer, 4);
s_pSecFn->FreeContextBuffer(input_buf[1].pvBuffer);
free(chlg);
/* Extract the security layer */
sec_layer = indata & 0x000000FF;
if(!(sec_layer & KERB_WRAP_NO_ENCRYPT)) {
infof(data, "GSSAPI handshake failure (invalid security layer)\n");
return CURLE_BAD_CONTENT_ENCODING;
}
/* Extract the maximum message size the server can receive */
max_size = ntohl(indata & 0xFFFFFF00);
if(max_size > 0) {
/* The server has told us it supports a maximum receive buffer, however, as
we don't require one unless we are encrypting data, we tell the server
our receive buffer is zero. */
max_size = 0;
}
/* Allocate the trailer */
trailer = malloc(sizes.cbSecurityTrailer);
if(!trailer)
return CURLE_OUT_OF_MEMORY;
/* Convert the user name to UTF8 when operating with Unicode */
user_name = Curl_convert_tchar_to_UTF8(names.sUserName);
if(!user_name) {
free(trailer);
return CURLE_OUT_OF_MEMORY;
}
/* Allocate our message */
messagelen = sizeof(outdata) + strlen(user_name) + 1;
message = malloc(messagelen);
if(!message) {
free(trailer);
Curl_unicodefree(user_name);
return CURLE_OUT_OF_MEMORY;
}
/* Populate the message with the security layer, client supported receive
message size and authorization identity including the 0x00 based
terminator. Note: Despite RFC4752 Section 3.1 stating "The authorization
identity is not terminated with the zero-valued (%x00) octet." it seems
necessary to include it. */
outdata = htonl(max_size) | sec_layer;
memcpy(message, &outdata, sizeof(outdata));
strcpy((char *) message + sizeof(outdata), user_name);
Curl_unicodefree(user_name);
/* Allocate the padding */
padding = malloc(sizes.cbBlockSize);
if(!padding) {
free(message);
free(trailer);
return CURLE_OUT_OF_MEMORY;
}
/* Setup the "authentication data" security buffer */
wrap_desc.ulVersion = SECBUFFER_VERSION;
wrap_desc.cBuffers = 3;
wrap_desc.pBuffers = wrap_buf;
wrap_buf[0].BufferType = SECBUFFER_TOKEN;
wrap_buf[0].pvBuffer = trailer;
wrap_buf[0].cbBuffer = sizes.cbSecurityTrailer;
wrap_buf[1].BufferType = SECBUFFER_DATA;
wrap_buf[1].pvBuffer = message;
wrap_buf[1].cbBuffer = curlx_uztoul(messagelen);
wrap_buf[2].BufferType = SECBUFFER_PADDING;
wrap_buf[2].pvBuffer = padding;
wrap_buf[2].cbBuffer = sizes.cbBlockSize;
/* Encrypt the data */
status = s_pSecFn->EncryptMessage(krb5->context, KERB_WRAP_NO_ENCRYPT,
&wrap_desc, 0);
if(status != SEC_E_OK) {
free(padding);
free(message);
free(trailer);
return CURLE_OUT_OF_MEMORY;
}
/* Allocate the encryption (wrap) buffer */
appdatalen = wrap_buf[0].cbBuffer + wrap_buf[1].cbBuffer +
wrap_buf[2].cbBuffer;
appdata = malloc(appdatalen);
if(!appdata) {
free(padding);
free(message);
free(trailer);
return CURLE_OUT_OF_MEMORY;
}
/* Populate the encryption buffer */
memcpy(appdata, wrap_buf[0].pvBuffer, wrap_buf[0].cbBuffer);
offset += wrap_buf[0].cbBuffer;
memcpy(appdata + offset, wrap_buf[1].pvBuffer, wrap_buf[1].cbBuffer);
offset += wrap_buf[1].cbBuffer;
memcpy(appdata + offset, wrap_buf[2].pvBuffer, wrap_buf[2].cbBuffer);
/* Base64 encode the response */
result = Curl_base64_encode(data, (char *) appdata, appdatalen, outptr,
outlen);
/* Free all of our local buffers */
free(appdata);
free(padding);
free(message);
free(trailer);
return result;
}
/*
* Curl_auth_gssapi_cleanup()
*
* This is used to clean up the GSSAPI (Kerberos V5) specific data.
*
* Parameters:
*
* krb5 [in/out] - The Kerberos 5 data struct being cleaned up.
*
*/
void Curl_auth_gssapi_cleanup(struct kerberos5data *krb5)
{
/* Free our security context */
if(krb5->context) {
s_pSecFn->DeleteSecurityContext(krb5->context);
free(krb5->context);
krb5->context = NULL;
}
/* Free our credentials handle */
if(krb5->credentials) {
s_pSecFn->FreeCredentialsHandle(krb5->credentials);
free(krb5->credentials);
krb5->credentials = NULL;
}
/* Free our identity */
Curl_sspi_free_identity(krb5->p_identity);
krb5->p_identity = NULL;
/* Free the SPN and output token */
Curl_safefree(krb5->spn);
Curl_safefree(krb5->output_token);
/* Reset any variables */
krb5->token_max = 0;
}
#endif /* USE_WINDOWS_SSPI && USE_KERBEROS5*/
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