gss-genr.c - third_party/openssh-portable - Git at Google

 /* $OpenBSD: gss-genr.c,v 1.23 2015/01/20 23:14:00 deraadt Exp $ */

 /*
  * Copyright (c) 2001-2007 Simon Wilkinson. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR `AS IS'' AND ANY EXPRESS OR
  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */

 #include "includes.h"

 #ifdef GSSAPI

 #include <sys/types.h>
 #include <sys/param.h>

 #include <limits.h>
 #include <stdarg.h>
 #include <string.h>
 #include <signal.h>
 #include <unistd.h>

 #include "xmalloc.h"
 #include "buffer.h"
 #include "log.h"
 #include "ssh2.h"

 #include "ssh-gss.h"

 extern u_char *session_id2;
 extern u_int session_id2_len;

 /* Check that the OID in a data stream matches that in the context */
 int
 ssh_gssapi_check_oid(Gssctxt *ctx, void *data, size_t len)
 {
 	return (ctx != NULL && ctx->oid != GSS_C_NO_OID &&
 	    ctx->oid->length == len &&
 	    memcmp(ctx->oid->elements, data, len) == 0);
 }

 /* Set the contexts OID from a data stream */
 void
 ssh_gssapi_set_oid_data(Gssctxt *ctx, void *data, size_t len)
 {
 	if (ctx->oid != GSS_C_NO_OID) {
 		free(ctx->oid->elements);
 		free(ctx->oid);
 	}
 	ctx->oid = xcalloc(1, sizeof(gss_OID_desc));
 	ctx->oid->length = len;
 	ctx->oid->elements = xmalloc(len);
 	memcpy(ctx->oid->elements, data, len);
 }

 /* Set the contexts OID */
 void
 ssh_gssapi_set_oid(Gssctxt *ctx, gss_OID oid)
 {
 	ssh_gssapi_set_oid_data(ctx, oid->elements, oid->length);
 }

 /* All this effort to report an error ... */
 void
 ssh_gssapi_error(Gssctxt *ctxt)
 {
 	char *s;

 	s = ssh_gssapi_last_error(ctxt, NULL, NULL);
 	debug("%s", s);
 	free(s);
 }

 char *
 ssh_gssapi_last_error(Gssctxt *ctxt, OM_uint32 *major_status,
     OM_uint32 *minor_status)
 {
 	OM_uint32 lmin;
 	gss_buffer_desc msg = GSS_C_EMPTY_BUFFER;
 	OM_uint32 ctx;
 	Buffer b;
 	char *ret;

 	buffer_init(&b);

 	if (major_status != NULL)
 		*major_status = ctxt->major;
 	if (minor_status != NULL)
 		*minor_status = ctxt->minor;

 	ctx = 0;
 	/* The GSSAPI error */
 	do {
 		gss_display_status(&lmin, ctxt->major,
 		    GSS_C_GSS_CODE, ctxt->oid, &ctx, &msg);

 		buffer_append(&b, msg.value, msg.length);
 		buffer_put_char(&b, '\n');

 		gss_release_buffer(&lmin, &msg);
 	} while (ctx != 0);

 	/* The mechanism specific error */
 	do {
 		gss_display_status(&lmin, ctxt->minor,
 		    GSS_C_MECH_CODE, ctxt->oid, &ctx, &msg);

 		buffer_append(&b, msg.value, msg.length);
 		buffer_put_char(&b, '\n');

 		gss_release_buffer(&lmin, &msg);
 	} while (ctx != 0);

 	buffer_put_char(&b, '\0');
 	ret = xmalloc(buffer_len(&b));
 	buffer_get(&b, ret, buffer_len(&b));
 	buffer_free(&b);
 	return (ret);
 }

 /*
  * Initialise our GSSAPI context. We use this opaque structure to contain all
  * of the data which both the client and server need to persist across
  * {accept,init}_sec_context calls, so that when we do it from the userauth
  * stuff life is a little easier
  */
 void
 ssh_gssapi_build_ctx(Gssctxt **ctx)
 {
 	*ctx = xcalloc(1, sizeof (Gssctxt));
 	(*ctx)->context = GSS_C_NO_CONTEXT;
 	(*ctx)->name = GSS_C_NO_NAME;
 	(*ctx)->oid = GSS_C_NO_OID;
 	(*ctx)->creds = GSS_C_NO_CREDENTIAL;
 	(*ctx)->client = GSS_C_NO_NAME;
 	(*ctx)->client_creds = GSS_C_NO_CREDENTIAL;
 }

 /* Delete our context, providing it has been built correctly */
 void
 ssh_gssapi_delete_ctx(Gssctxt **ctx)
 {
 	OM_uint32 ms;

 	if ((*ctx) == NULL)
 		return;
 	if ((*ctx)->context != GSS_C_NO_CONTEXT)
 		gss_delete_sec_context(&ms, &(*ctx)->context, GSS_C_NO_BUFFER);
 	if ((*ctx)->name != GSS_C_NO_NAME)
 		gss_release_name(&ms, &(*ctx)->name);
 	if ((*ctx)->oid != GSS_C_NO_OID) {
 		free((*ctx)->oid->elements);
 		free((*ctx)->oid);
 		(*ctx)->oid = GSS_C_NO_OID;
 	}
 	if ((*ctx)->creds != GSS_C_NO_CREDENTIAL)
 		gss_release_cred(&ms, &(*ctx)->creds);
 	if ((*ctx)->client != GSS_C_NO_NAME)
 		gss_release_name(&ms, &(*ctx)->client);
 	if ((*ctx)->client_creds != GSS_C_NO_CREDENTIAL)
 		gss_release_cred(&ms, &(*ctx)->client_creds);

 	free(*ctx);
 	*ctx = NULL;
 }

 /*
  * Wrapper to init_sec_context
  * Requires that the context contains:
  *	oid
  *	server name (from ssh_gssapi_import_name)
  */
 OM_uint32
 ssh_gssapi_init_ctx(Gssctxt *ctx, int deleg_creds, gss_buffer_desc *recv_tok,
     gss_buffer_desc* send_tok, OM_uint32 *flags)
 {
 	int deleg_flag = 0;

 	if (deleg_creds) {
 		deleg_flag = GSS_C_DELEG_FLAG;
 		debug("Delegating credentials");
 	}

 	ctx->major = gss_init_sec_context(&ctx->minor,
 	    GSS_C_NO_CREDENTIAL, &ctx->context, ctx->name, ctx->oid,
 	    GSS_C_MUTUAL_FLAG | GSS_C_INTEG_FLAG | deleg_flag,
 	    0, NULL, recv_tok, NULL, send_tok, flags, NULL);

 	if (GSS_ERROR(ctx->major))
 		ssh_gssapi_error(ctx);

 	return (ctx->major);
 }

 /* Create a service name for the given host */
 OM_uint32
 ssh_gssapi_import_name(Gssctxt *ctx, const char *host)
 {
 	gss_buffer_desc gssbuf;
 	char *val;

 	xasprintf(&val, "host@%s", host);
 	gssbuf.value = val;
 	gssbuf.length = strlen(gssbuf.value);

 	if ((ctx->major = gss_import_name(&ctx->minor,
 	    &gssbuf, GSS_C_NT_HOSTBASED_SERVICE, &ctx->name)))
 		ssh_gssapi_error(ctx);

 	free(gssbuf.value);
 	return (ctx->major);
 }

 OM_uint32
 ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash)
 {
 	if ((ctx->major = gss_get_mic(&ctx->minor, ctx->context,
 	    GSS_C_QOP_DEFAULT, buffer, hash)))
 		ssh_gssapi_error(ctx);

 	return (ctx->major);
 }

 void
 ssh_gssapi_buildmic(Buffer *b, const char *user, const char *service,
     const char *context)
 {
 	buffer_init(b);
 	buffer_put_string(b, session_id2, session_id2_len);
 	buffer_put_char(b, SSH2_MSG_USERAUTH_REQUEST);
 	buffer_put_cstring(b, user);
 	buffer_put_cstring(b, service);
 	buffer_put_cstring(b, context);
 }

 int
 ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host)
 {
 	gss_buffer_desc token = GSS_C_EMPTY_BUFFER;
 	OM_uint32 major, minor;
 	gss_OID_desc spnego_oid = {6, (void *)"\x2B\x06\x01\x05\x05\x02"};

 	/* RFC 4462 says we MUST NOT do SPNEGO */
 	if (oid->length == spnego_oid.length &&
 	    (memcmp(oid->elements, spnego_oid.elements, oid->length) == 0))
 		return 0; /* false */

 	ssh_gssapi_build_ctx(ctx);
 	ssh_gssapi_set_oid(*ctx, oid);
 	major = ssh_gssapi_import_name(*ctx, host);
 	if (!GSS_ERROR(major)) {
 		major = ssh_gssapi_init_ctx(*ctx, 0, GSS_C_NO_BUFFER, &token,
 		    NULL);
 		gss_release_buffer(&minor, &token);
 		if ((*ctx)->context != GSS_C_NO_CONTEXT)
 			gss_delete_sec_context(&minor, &(*ctx)->context,
 			    GSS_C_NO_BUFFER);
 	}

 	if (GSS_ERROR(major))
 		ssh_gssapi_delete_ctx(ctx);

 	return (!GSS_ERROR(major));
 }

 #endif /* GSSAPI */
	/* $OpenBSD: gss-genr.c,v 1.23 2015/01/20 23:14:00 deraadt Exp $ */

	/*
	* Copyright (c) 2001-2007 Simon Wilkinson. All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution.
	*
	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR `AS IS'' AND ANY EXPRESS OR
	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	#include "includes.h"

	#ifdef GSSAPI

	#include <sys/types.h>
	#include <sys/param.h>

	#include <limits.h>
	#include <stdarg.h>
	#include <string.h>
	#include <signal.h>
	#include <unistd.h>

	#include "xmalloc.h"
	#include "buffer.h"
	#include "log.h"
	#include "ssh2.h"

	#include "ssh-gss.h"

	extern u_char *session_id2;
	extern u_int session_id2_len;

	/* Check that the OID in a data stream matches that in the context */
	int
	ssh_gssapi_check_oid(Gssctxt ctx, void data, size_t len)
	{
	return (ctx != NULL && ctx->oid != GSS_C_NO_OID &&
	ctx->oid->length == len &&
	memcmp(ctx->oid->elements, data, len) == 0);
	}

	/* Set the contexts OID from a data stream */
	void
	ssh_gssapi_set_oid_data(Gssctxt ctx, void data, size_t len)
	{
	if (ctx->oid != GSS_C_NO_OID) {
	free(ctx->oid->elements);
	free(ctx->oid);
	}
	ctx->oid = xcalloc(1, sizeof(gss_OID_desc));
	ctx->oid->length = len;
	ctx->oid->elements = xmalloc(len);
	memcpy(ctx->oid->elements, data, len);
	}

	/* Set the contexts OID */
	void
	ssh_gssapi_set_oid(Gssctxt *ctx, gss_OID oid)
	{
	ssh_gssapi_set_oid_data(ctx, oid->elements, oid->length);
	}

	/* All this effort to report an error ... */
	void
	ssh_gssapi_error(Gssctxt *ctxt)
	{
	char *s;

	s = ssh_gssapi_last_error(ctxt, NULL, NULL);
	debug("%s", s);
	free(s);
	}

	char *
	ssh_gssapi_last_error(Gssctxt ctxt, OM_uint32 major_status,
	OM_uint32 *minor_status)
	{
	OM_uint32 lmin;
	gss_buffer_desc msg = GSS_C_EMPTY_BUFFER;
	OM_uint32 ctx;
	Buffer b;
	char *ret;

	buffer_init(&b);

	if (major_status != NULL)
	*major_status = ctxt->major;
	if (minor_status != NULL)
	*minor_status = ctxt->minor;

	ctx = 0;
	/* The GSSAPI error */
	do {
	gss_display_status(&lmin, ctxt->major,
	GSS_C_GSS_CODE, ctxt->oid, &ctx, &msg);

	buffer_append(&b, msg.value, msg.length);
	buffer_put_char(&b, '\n');

	gss_release_buffer(&lmin, &msg);
	} while (ctx != 0);

	/* The mechanism specific error */
	do {
	gss_display_status(&lmin, ctxt->minor,
	GSS_C_MECH_CODE, ctxt->oid, &ctx, &msg);

	buffer_append(&b, msg.value, msg.length);
	buffer_put_char(&b, '\n');

	gss_release_buffer(&lmin, &msg);
	} while (ctx != 0);

	buffer_put_char(&b, '\0');
	ret = xmalloc(buffer_len(&b));
	buffer_get(&b, ret, buffer_len(&b));
	buffer_free(&b);
	return (ret);
	}

	/*
	* Initialise our GSSAPI context. We use this opaque structure to contain all
	* of the data which both the client and server need to persist across
	* {accept,init}_sec_context calls, so that when we do it from the userauth
	* stuff life is a little easier
	*/
	void
	ssh_gssapi_build_ctx(Gssctxt **ctx)
	{
	*ctx = xcalloc(1, sizeof (Gssctxt));
	(*ctx)->context = GSS_C_NO_CONTEXT;
	(*ctx)->name = GSS_C_NO_NAME;
	(*ctx)->oid = GSS_C_NO_OID;
	(*ctx)->creds = GSS_C_NO_CREDENTIAL;
	(*ctx)->client = GSS_C_NO_NAME;
	(*ctx)->client_creds = GSS_C_NO_CREDENTIAL;
	}

	/* Delete our context, providing it has been built correctly */
	void
	ssh_gssapi_delete_ctx(Gssctxt **ctx)
	{
	OM_uint32 ms;

	if ((*ctx) == NULL)
	return;
	if ((*ctx)->context != GSS_C_NO_CONTEXT)
	gss_delete_sec_context(&ms, &(*ctx)->context, GSS_C_NO_BUFFER);
	if ((*ctx)->name != GSS_C_NO_NAME)
	gss_release_name(&ms, &(*ctx)->name);
	if ((*ctx)->oid != GSS_C_NO_OID) {
	free((*ctx)->oid->elements);
	free((*ctx)->oid);
	(*ctx)->oid = GSS_C_NO_OID;
	}
	if ((*ctx)->creds != GSS_C_NO_CREDENTIAL)
	gss_release_cred(&ms, &(*ctx)->creds);
	if ((*ctx)->client != GSS_C_NO_NAME)
	gss_release_name(&ms, &(*ctx)->client);
	if ((*ctx)->client_creds != GSS_C_NO_CREDENTIAL)
	gss_release_cred(&ms, &(*ctx)->client_creds);

	free(*ctx);
	*ctx = NULL;
	}

	/*
	* Wrapper to init_sec_context
	* Requires that the context contains:
	* oid
	* server name (from ssh_gssapi_import_name)
	*/
	OM_uint32
	ssh_gssapi_init_ctx(Gssctxt ctx, int deleg_creds, gss_buffer_desc recv_tok,
	gss_buffer_desc* send_tok, OM_uint32 *flags)
	{
	int deleg_flag = 0;

	if (deleg_creds) {
	deleg_flag = GSS_C_DELEG_FLAG;
	debug("Delegating credentials");
	}

	ctx->major = gss_init_sec_context(&ctx->minor,
	GSS_C_NO_CREDENTIAL, &ctx->context, ctx->name, ctx->oid,
	GSS_C_MUTUAL_FLAG \| GSS_C_INTEG_FLAG \| deleg_flag,
	0, NULL, recv_tok, NULL, send_tok, flags, NULL);

	if (GSS_ERROR(ctx->major))
	ssh_gssapi_error(ctx);

	return (ctx->major);
	}

	/* Create a service name for the given host */
	OM_uint32
	ssh_gssapi_import_name(Gssctxt ctx, const char host)
	{
	gss_buffer_desc gssbuf;
	char *val;

	xasprintf(&val, "host@%s", host);
	gssbuf.value = val;
	gssbuf.length = strlen(gssbuf.value);

	if ((ctx->major = gss_import_name(&ctx->minor,
	&gssbuf, GSS_C_NT_HOSTBASED_SERVICE, &ctx->name)))
	ssh_gssapi_error(ctx);

	free(gssbuf.value);
	return (ctx->major);
	}

	OM_uint32
	ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash)
	{
	if ((ctx->major = gss_get_mic(&ctx->minor, ctx->context,
	GSS_C_QOP_DEFAULT, buffer, hash)))
	ssh_gssapi_error(ctx);

	return (ctx->major);
	}

	void
	ssh_gssapi_buildmic(Buffer b, const char user, const char *service,
	const char *context)
	{
	buffer_init(b);
	buffer_put_string(b, session_id2, session_id2_len);
	buffer_put_char(b, SSH2_MSG_USERAUTH_REQUEST);
	buffer_put_cstring(b, user);
	buffer_put_cstring(b, service);
	buffer_put_cstring(b, context);
	}

	int
	ssh_gssapi_check_mechanism(Gssctxt *ctx, gss_OID oid, const char host)
	{
	gss_buffer_desc token = GSS_C_EMPTY_BUFFER;
	OM_uint32 major, minor;
	gss_OID_desc spnego_oid = {6, (void *)"\x2B\x06\x01\x05\x05\x02"};

	/* RFC 4462 says we MUST NOT do SPNEGO */
	if (oid->length == spnego_oid.length &&
	(memcmp(oid->elements, spnego_oid.elements, oid->length) == 0))
	return 0; /* false */

	ssh_gssapi_build_ctx(ctx);
	ssh_gssapi_set_oid(*ctx, oid);
	major = ssh_gssapi_import_name(*ctx, host);
	if (!GSS_ERROR(major)) {
	major = ssh_gssapi_init_ctx(*ctx, 0, GSS_C_NO_BUFFER, &token,
	NULL);
	gss_release_buffer(&minor, &token);
	if ((*ctx)->context != GSS_C_NO_CONTEXT)
	gss_delete_sec_context(&minor, &(*ctx)->context,
	GSS_C_NO_BUFFER);
	}

	if (GSS_ERROR(major))
	ssh_gssapi_delete_ctx(ctx);

	return (!GSS_ERROR(major));
	}

	#endif /* GSSAPI */