curl/lib/http_negotiate.c
Daniel Stenberg 5c314c6bb4 Curl_input_negotiate: do not delegate GSSAPI credentials
This is a security flaw. See curl advisory 20110623 for details.

Reported by: Richard Silverman
2011-06-22 23:04:26 +02:00

371 lines
11 KiB
C

/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2011, 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 http://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.
*
***************************************************************************/
#include "setup.h"
#ifdef HAVE_GSSAPI
#ifdef HAVE_OLD_GSSMIT
#define GSS_C_NT_HOSTBASED_SERVICE gss_nt_service_name
#endif
#ifndef CURL_DISABLE_HTTP
/* -- WIN32 approved -- */
#include <stdio.h>
#include <string.h>
#include <stdarg.h>
#include <stdlib.h>
#include <ctype.h>
#include "urldata.h"
#include "sendf.h"
#include "rawstr.h"
#include "curl_base64.h"
#include "http_negotiate.h"
#include "curl_memory.h"
#ifdef HAVE_SPNEGO
# include <spnegohelp.h>
# ifdef USE_SSLEAY
# ifdef USE_OPENSSL
# include <openssl/objects.h>
# else
# include <objects.h>
# endif
# else
# error "Can't compile SPNEGO support without OpenSSL."
# endif
#endif
#define _MPRINTF_REPLACE /* use our functions only */
#include <curl/mprintf.h>
/* The last #include file should be: */
#include "memdebug.h"
static int
get_gss_name(struct connectdata *conn, bool proxy, gss_name_t *server)
{
struct negotiatedata *neg_ctx = proxy?&conn->data->state.proxyneg:
&conn->data->state.negotiate;
OM_uint32 major_status, minor_status;
gss_buffer_desc token = GSS_C_EMPTY_BUFFER;
char name[2048];
const char* service;
/* GSSAPI implementation by Globus (known as GSI) requires the name to be
of form "<service>/<fqdn>" instead of <service>@<fqdn> (ie. slash instead
of at-sign). Also GSI servers are often identified as 'host' not 'khttp'.
Change following lines if you want to use GSI */
/* IIS uses the <service>@<fqdn> form but uses 'http' as the service name */
if(neg_ctx->gss)
service = "KHTTP";
else
service = "HTTP";
token.length = strlen(service) + 1 + strlen(proxy ? conn->proxy.name :
conn->host.name) + 1;
if(token.length + 1 > sizeof(name))
return EMSGSIZE;
snprintf(name, sizeof(name), "%s@%s", service, proxy ? conn->proxy.name :
conn->host.name);
token.value = (void *) name;
major_status = gss_import_name(&minor_status,
&token,
GSS_C_NT_HOSTBASED_SERVICE,
server);
return GSS_ERROR(major_status) ? -1 : 0;
}
static void
log_gss_error(struct connectdata *conn, OM_uint32 error_status,
const char *prefix)
{
OM_uint32 maj_stat, min_stat;
OM_uint32 msg_ctx = 0;
gss_buffer_desc status_string;
char buf[1024];
size_t len;
snprintf(buf, sizeof(buf), "%s", prefix);
len = strlen(buf);
do {
maj_stat = gss_display_status(&min_stat,
error_status,
GSS_C_MECH_CODE,
GSS_C_NO_OID,
&msg_ctx,
&status_string);
if(sizeof(buf) > len + status_string.length + 1) {
snprintf(buf + len, sizeof(buf) - len,
": %s", (char*) status_string.value);
len += status_string.length;
}
gss_release_buffer(&min_stat, &status_string);
} while(!GSS_ERROR(maj_stat) && msg_ctx != 0);
infof(conn->data, "%s", buf);
}
/* returning zero (0) means success, everything else is treated as "failure"
with no care exactly what the failure was */
int Curl_input_negotiate(struct connectdata *conn, bool proxy,
const char *header)
{
struct negotiatedata *neg_ctx = proxy?&conn->data->state.proxyneg:
&conn->data->state.negotiate;
OM_uint32 major_status, minor_status, minor_status2;
gss_buffer_desc input_token = GSS_C_EMPTY_BUFFER;
gss_buffer_desc output_token = GSS_C_EMPTY_BUFFER;
int ret;
size_t len, rawlen;
bool gss;
const char* protocol;
while(*header && ISSPACE(*header))
header++;
if(checkprefix("GSS-Negotiate", header)) {
protocol = "GSS-Negotiate";
gss = TRUE;
}
else if(checkprefix("Negotiate", header)) {
protocol = "Negotiate";
gss = FALSE;
}
else
return -1;
if(neg_ctx->context) {
if(neg_ctx->gss != gss) {
return -1;
}
}
else {
neg_ctx->protocol = protocol;
neg_ctx->gss = gss;
}
if(neg_ctx->context && neg_ctx->status == GSS_S_COMPLETE) {
/* 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_cleanup_negotiate(conn->data);
return -1;
}
if(neg_ctx->server_name == NULL &&
(ret = get_gss_name(conn, proxy, &neg_ctx->server_name)))
return ret;
header += strlen(neg_ctx->protocol);
while(*header && ISSPACE(*header))
header++;
len = strlen(header);
if(len > 0) {
rawlen = Curl_base64_decode(header,
(unsigned char **)&input_token.value);
if(rawlen == 0)
return -1;
input_token.length = rawlen;
#ifdef HAVE_SPNEGO /* Handle SPNEGO */
if(checkprefix("Negotiate", header)) {
ASN1_OBJECT * object = NULL;
int rc = 1;
unsigned char * spnegoToken = NULL;
size_t spnegoTokenLength = 0;
unsigned char * mechToken = NULL;
size_t mechTokenLength = 0;
if(input_token.value == NULL)
return CURLE_OUT_OF_MEMORY;
spnegoToken = malloc(input_token.length);
if(spnegoToken == NULL)
return CURLE_OUT_OF_MEMORY;
spnegoTokenLength = input_token.length;
object = OBJ_txt2obj ("1.2.840.113554.1.2.2", 1);
if(!parseSpnegoTargetToken(spnegoToken,
spnegoTokenLength,
NULL,
NULL,
&mechToken,
&mechTokenLength,
NULL,
NULL)) {
free(spnegoToken);
spnegoToken = NULL;
infof(conn->data, "Parse SPNEGO Target Token failed\n");
}
else {
free(input_token.value);
input_token.value = malloc(mechTokenLength);
if(input_token.value == NULL)
return CURLE_OUT_OF_MEMORY;
memcpy(input_token.value, mechToken,mechTokenLength);
input_token.length = mechTokenLength;
free(mechToken);
mechToken = NULL;
infof(conn->data, "Parse SPNEGO Target Token succeeded\n");
}
}
#endif
}
major_status = gss_init_sec_context(&minor_status,
GSS_C_NO_CREDENTIAL,
&neg_ctx->context,
neg_ctx->server_name,
GSS_C_NO_OID,
0,
0,
GSS_C_NO_CHANNEL_BINDINGS,
&input_token,
NULL,
&output_token,
NULL,
NULL);
if(input_token.length > 0)
gss_release_buffer(&minor_status2, &input_token);
neg_ctx->status = major_status;
if(GSS_ERROR(major_status)) {
/* Curl_cleanup_negotiate(conn->data) ??? */
log_gss_error(conn, minor_status,
"gss_init_sec_context() failed: ");
return -1;
}
if(output_token.length == 0) {
return -1;
}
neg_ctx->output_token = output_token;
/* conn->bits.close = FALSE; */
return 0;
}
CURLcode Curl_output_negotiate(struct connectdata *conn, bool proxy)
{
struct negotiatedata *neg_ctx = proxy?&conn->data->state.proxyneg:
&conn->data->state.negotiate;
char *encoded = NULL;
size_t len;
char *userp;
#ifdef HAVE_SPNEGO /* Handle SPNEGO */
if(checkprefix("Negotiate", neg_ctx->protocol)) {
ASN1_OBJECT * object = NULL;
int rc = 1;
unsigned char * spnegoToken = NULL;
size_t spnegoTokenLength = 0;
unsigned char * responseToken = NULL;
size_t responseTokenLength = 0;
responseToken = malloc(neg_ctx->output_token.length);
if(responseToken == NULL)
return CURLE_OUT_OF_MEMORY;
memcpy(responseToken, neg_ctx->output_token.value,
neg_ctx->output_token.length);
responseTokenLength = neg_ctx->output_token.length;
object=OBJ_txt2obj ("1.2.840.113554.1.2.2", 1);
if(!makeSpnegoInitialToken (object,
responseToken,
responseTokenLength,
&spnegoToken,
&spnegoTokenLength)) {
free(responseToken);
responseToken = NULL;
infof(conn->data, "Make SPNEGO Initial Token failed\n");
}
else {
free(responseToken);
responseToken = NULL;
free(neg_ctx->output_token.value);
neg_ctx->output_token.value = malloc(spnegoTokenLength);
if(neg_ctx->output_token.value == NULL) {
free(spnegoToken);
spnegoToken = NULL;
return CURLE_OUT_OF_MEMORY;
}
memcpy(neg_ctx->output_token.value, spnegoToken,spnegoTokenLength);
neg_ctx->output_token.length = spnegoTokenLength;
free(spnegoToken);
spnegoToken = NULL;
infof(conn->data, "Make SPNEGO Initial Token succeeded\n");
}
}
#endif
len = Curl_base64_encode(conn->data,
neg_ctx->output_token.value,
neg_ctx->output_token.length,
&encoded);
if(len == 0)
return CURLE_OUT_OF_MEMORY;
userp = aprintf("%sAuthorization: %s %s\r\n", proxy ? "Proxy-" : "",
neg_ctx->protocol, encoded);
if(proxy)
conn->allocptr.proxyuserpwd = userp;
else
conn->allocptr.userpwd = userp;
free(encoded);
Curl_cleanup_negotiate (conn->data);
return (userp == NULL) ? CURLE_OUT_OF_MEMORY : CURLE_OK;
}
static void cleanup(struct negotiatedata *neg_ctx)
{
OM_uint32 minor_status;
if(neg_ctx->context != GSS_C_NO_CONTEXT)
gss_delete_sec_context(&minor_status, &neg_ctx->context, GSS_C_NO_BUFFER);
if(neg_ctx->output_token.length != 0)
gss_release_buffer(&minor_status, &neg_ctx->output_token);
if(neg_ctx->server_name != GSS_C_NO_NAME)
gss_release_name(&minor_status, &neg_ctx->server_name);
memset(neg_ctx, 0, sizeof(*neg_ctx));
}
void Curl_cleanup_negotiate(struct SessionHandle *data)
{
cleanup(&data->state.negotiate);
cleanup(&data->state.proxyneg);
}
#endif
#endif