/*
 * Copyright (c) 1997 - 2007 Kungliga Tekniska Högskolan
 * (Royal Institute of Technology, Stockholm, Sweden). 
 * 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. 
 *
 * 3. Neither the name of the Institute nor the names of its contributors 
 *    may be used to endorse or promote products derived from this software 
 *    without specific prior written permission. 
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``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 INSTITUTE OR CONTRIBUTORS 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 "krb5/gsskrb5_locl.h"

RCSID("$Id: init_sec_context.c 22071 2007-11-14 20:04:50Z lha $");

/*
 * copy the addresses from `input_chan_bindings' (if any) to
 * the auth context `ac'
 */

static OM_uint32
set_addresses (krb5_context context,
	       krb5_auth_context ac,
	       const gss_channel_bindings_t input_chan_bindings)	       
{
    /* Port numbers are expected to be in application_data.value, 
     * initator's port first */ 

    krb5_address initiator_addr, acceptor_addr;
    krb5_error_code kret;
       
    if (input_chan_bindings == GSS_C_NO_CHANNEL_BINDINGS
	|| input_chan_bindings->application_data.length !=
	2 * sizeof(ac->local_port))
	return 0;

    memset(&initiator_addr, 0, sizeof(initiator_addr));
    memset(&acceptor_addr, 0, sizeof(acceptor_addr));
       
    ac->local_port =
	*(int16_t *) input_chan_bindings->application_data.value;
       
    ac->remote_port =
	*((int16_t *) input_chan_bindings->application_data.value + 1);
       
    kret = _gsskrb5i_address_to_krb5addr(context,
					 input_chan_bindings->acceptor_addrtype,
					 &input_chan_bindings->acceptor_address,
					 ac->remote_port,
					 &acceptor_addr);
    if (kret)
	return kret;
           
    kret = _gsskrb5i_address_to_krb5addr(context,
					 input_chan_bindings->initiator_addrtype,
					 &input_chan_bindings->initiator_address,
					 ac->local_port,
					 &initiator_addr);
    if (kret) {
	krb5_free_address (context, &acceptor_addr);
	return kret;
    }
       
    kret = krb5_auth_con_setaddrs(context,
				  ac,
				  &initiator_addr,  /* local address */
				  &acceptor_addr);  /* remote address */
       
    krb5_free_address (context, &initiator_addr);
    krb5_free_address (context, &acceptor_addr);
       
#if 0
    free(input_chan_bindings->application_data.value);
    input_chan_bindings->application_data.value = NULL;
    input_chan_bindings->application_data.length = 0;
#endif

    return kret;
}

OM_uint32
_gsskrb5_create_ctx(
        OM_uint32 * minor_status,
	gss_ctx_id_t * context_handle,
	krb5_context context,
 	const gss_channel_bindings_t input_chan_bindings,
 	enum gss_ctx_id_t_state state)
{
    krb5_error_code kret;
    gsskrb5_ctx ctx;

    *context_handle = NULL;

    ctx = malloc(sizeof(*ctx));
    if (ctx == NULL) {
	*minor_status = ENOMEM;
	return GSS_S_FAILURE;
    }
    ctx->auth_context		= NULL;
    ctx->source			= NULL;
    ctx->target			= NULL;
    ctx->state			= state;
    ctx->flags			= 0;
    ctx->more_flags		= 0;
    ctx->service_keyblock	= NULL;
    ctx->ticket			= NULL;
    krb5_data_zero(&ctx->fwd_data);
    ctx->lifetime		= GSS_C_INDEFINITE;
    ctx->order			= NULL;
    HEIMDAL_MUTEX_init(&ctx->ctx_id_mutex);

    kret = krb5_auth_con_init (context, &ctx->auth_context);
    if (kret) {
	*minor_status = kret;

	HEIMDAL_MUTEX_destroy(&ctx->ctx_id_mutex);
		
	return GSS_S_FAILURE;
    }

    kret = set_addresses(context, ctx->auth_context, input_chan_bindings);
    if (kret) {
	*minor_status = kret;

	HEIMDAL_MUTEX_destroy(&ctx->ctx_id_mutex);

	krb5_auth_con_free(context, ctx->auth_context);

	return GSS_S_BAD_BINDINGS;
    }

    /*
     * We need a sequence number
     */

    krb5_auth_con_addflags(context,
			   ctx->auth_context,
			   KRB5_AUTH_CONTEXT_DO_SEQUENCE |
			   KRB5_AUTH_CONTEXT_CLEAR_FORWARDED_CRED,
			   NULL);

    *context_handle = (gss_ctx_id_t)ctx;

    return GSS_S_COMPLETE;
}


static OM_uint32
gsskrb5_get_creds(
        OM_uint32 * minor_status,
	krb5_context context,
	krb5_ccache ccache,
	gsskrb5_ctx ctx,
	krb5_const_principal target_name,
	OM_uint32 time_req,
	OM_uint32 * time_rec,
	krb5_creds ** cred)
{
    OM_uint32 ret;
    krb5_error_code kret;
    krb5_creds this_cred;
    OM_uint32 lifetime_rec;

    *cred = NULL;

    memset(&this_cred, 0, sizeof(this_cred));
    this_cred.client = ctx->source;
    this_cred.server = ctx->target;

    if (time_req && time_req != GSS_C_INDEFINITE) {
	krb5_timestamp ts;

	krb5_timeofday (context, &ts);
	this_cred.times.endtime = ts + time_req;
    } else {
	this_cred.times.endtime   = 0;
    }

    this_cred.session.keytype = KEYTYPE_NULL;

    kret = krb5_get_credentials(context,
				0,
				ccache,
				&this_cred,
				cred);
    if (kret) {
	*minor_status = kret;
	return GSS_S_FAILURE;
    }

    ctx->lifetime = (*cred)->times.endtime;

    ret = _gsskrb5_lifetime_left(minor_status, context,
				 ctx->lifetime, &lifetime_rec);
    if (ret) return ret;

    if (lifetime_rec == 0) {
	*minor_status = 0;
	return GSS_S_CONTEXT_EXPIRED;
    }

    if (time_rec) *time_rec = lifetime_rec;

    return GSS_S_COMPLETE;
}

static OM_uint32
gsskrb5_initiator_ready(
	OM_uint32 * minor_status,
	gsskrb5_ctx ctx,
	krb5_context context)
{
	OM_uint32 ret;
	int32_t seq_number;
	int is_cfx = 0;
	OM_uint32 flags = ctx->flags;

	krb5_auth_getremoteseqnumber (context,
				      ctx->auth_context,
				      &seq_number);

	_gsskrb5i_is_cfx(ctx, &is_cfx);

	ret = _gssapi_msg_order_create(minor_status,
				       &ctx->order,
				       _gssapi_msg_order_f(flags),
				       seq_number, 0, is_cfx);
	if (ret) return ret;

	ctx->state	= INITIATOR_READY;
	ctx->more_flags	|= OPEN;

	return GSS_S_COMPLETE;
}

/*
 * handle delegated creds in init-sec-context
 */

static void
do_delegation (krb5_context context,
	       krb5_auth_context ac,
	       krb5_ccache ccache,
	       krb5_creds *cred,
	       krb5_const_principal name,
	       krb5_data *fwd_data,
	       uint32_t *flags)
{
    krb5_creds creds;
    KDCOptions fwd_flags;
    krb5_error_code kret;
       
    memset (&creds, 0, sizeof(creds));
    krb5_data_zero (fwd_data);
       
    kret = krb5_cc_get_principal(context, ccache, &creds.client);
    if (kret) 
	goto out;
       
    kret = krb5_build_principal(context,
				&creds.server,
				strlen(creds.client->realm),
				creds.client->realm,
				KRB5_TGS_NAME,
				creds.client->realm,
				NULL);
    if (kret)
	goto out; 
       
    creds.times.endtime = 0;
       
    memset(&fwd_flags, 0, sizeof(fwd_flags));
    fwd_flags.forwarded = 1;
    fwd_flags.forwardable = 1;
       
    if ( /*target_name->name.name_type != KRB5_NT_SRV_HST ||*/
	name->name.name_string.len < 2) 
	goto out;
       
    kret = krb5_get_forwarded_creds(context,
				    ac,
				    ccache,
				    KDCOptions2int(fwd_flags),
				    name->name.name_string.val[1],
				    &creds,
				    fwd_data);
       
 out:
    if (kret)
	*flags &= ~GSS_C_DELEG_FLAG;
    else
	*flags |= GSS_C_DELEG_FLAG;
       
    if (creds.client)
	krb5_free_principal(context, creds.client);
    if (creds.server)
	krb5_free_principal(context, creds.server);
}

/*
 * first stage of init-sec-context
 */

static OM_uint32
init_auth
(OM_uint32 * minor_status,
 gsskrb5_cred initiator_cred_handle,
 gsskrb5_ctx ctx,
 krb5_context context,
 krb5_const_principal name,
 const gss_OID mech_type,
 OM_uint32 req_flags,
 OM_uint32 time_req,
 const gss_channel_bindings_t input_chan_bindings,
 const gss_buffer_t input_token,
 gss_OID * actual_mech_type,
 gss_buffer_t output_token,
 OM_uint32 * ret_flags,
 OM_uint32 * time_rec
    )
{
    OM_uint32 ret = GSS_S_FAILURE;
    krb5_error_code kret;
    krb5_flags ap_options;
    krb5_creds *cred = NULL;
    krb5_data outbuf;
    krb5_ccache ccache = NULL;
    uint32_t flags;
    krb5_data authenticator;
    Checksum cksum;
    krb5_enctype enctype;
    krb5_data fwd_data;
    OM_uint32 lifetime_rec;

    krb5_data_zero(&outbuf);
    krb5_data_zero(&fwd_data);

    *minor_status = 0;

    if (actual_mech_type)
	*actual_mech_type = GSS_KRB5_MECHANISM;

    if (initiator_cred_handle == NULL) {
	kret = krb5_cc_default (context, &ccache);
	if (kret) {
	    *minor_status = kret;
	    ret = GSS_S_FAILURE;
	    goto failure;
	}
    } else
	ccache = initiator_cred_handle->ccache;

    kret = krb5_cc_get_principal (context, ccache, &ctx->source);
    if (kret) {
	*minor_status = kret;
	ret = GSS_S_FAILURE;
	goto failure;
    }

    kret = krb5_copy_principal (context, name, &ctx->target);
    if (kret) {
	*minor_status = kret;
	ret = GSS_S_FAILURE;
	goto failure;
    }

    ret = _gss_DES3_get_mic_compat(minor_status, ctx, context);
    if (ret)
	goto failure;


    /*
     * This is hideous glue for (NFS) clients that wants to limit the
     * available enctypes to what it can support (encryption in
     * kernel). If there is no enctypes selected for this credential,
     * reset it to the default set of enctypes.
     */
    {
	krb5_enctype *enctypes = NULL;

	if (initiator_cred_handle && initiator_cred_handle->enctypes)
	    enctypes = initiator_cred_handle->enctypes;
	krb5_set_default_in_tkt_etypes(context, enctypes);
    }

    ret = gsskrb5_get_creds(minor_status,
			    context,
			    ccache,
			    ctx,
			    ctx->target,
			    time_req,
			    time_rec,
			    &cred);
    if (ret)
	goto failure;

    ctx->lifetime = cred->times.endtime;

    ret = _gsskrb5_lifetime_left(minor_status,
				 context,
				 ctx->lifetime,
				 &lifetime_rec);
    if (ret) {
	goto failure;
    }

    if (lifetime_rec == 0) {
	*minor_status = 0;
	ret = GSS_S_CONTEXT_EXPIRED;
	goto failure;
    }

    krb5_auth_con_setkey(context, 
			 ctx->auth_context, 
			 &cred->session);

    kret = krb5_auth_con_generatelocalsubkey(context, 
					     ctx->auth_context,
					     &cred->session);
    if(kret) {
	*minor_status = kret;
	ret = GSS_S_FAILURE;
	goto failure;
    }
    
    /* 
     * If the credential doesn't have ok-as-delegate, check what local
     * policy say about ok-as-delegate, default is FALSE that makes
     * code ignore the KDC setting and follow what the application
     * requested. If it is TRUE, strip of the GSS_C_DELEG_FLAG if the
     * KDC doesn't set ok-as-delegate.
     */
    if (!cred->flags.b.ok_as_delegate) {
	krb5_boolean delegate;
    
	krb5_appdefault_boolean(context,
				"gssapi", name->realm,
				"ok-as-delegate", FALSE, &delegate);
	if (delegate)
	    req_flags &= ~GSS_C_DELEG_FLAG;
    }

    flags = 0;
    ap_options = 0;
    if (req_flags & GSS_C_DELEG_FLAG)
	do_delegation (context,
		       ctx->auth_context,
		       ccache, cred, name, &fwd_data, &flags);
    
    if (req_flags & GSS_C_MUTUAL_FLAG) {
	flags |= GSS_C_MUTUAL_FLAG;
	ap_options |= AP_OPTS_MUTUAL_REQUIRED;
    }
    
    if (req_flags & GSS_C_REPLAY_FLAG)
	flags |= GSS_C_REPLAY_FLAG;
    if (req_flags & GSS_C_SEQUENCE_FLAG)
	flags |= GSS_C_SEQUENCE_FLAG;
    if (req_flags & GSS_C_ANON_FLAG)
	;                               /* XXX */
    if (req_flags & GSS_C_DCE_STYLE) {
	/* GSS_C_DCE_STYLE implies GSS_C_MUTUAL_FLAG */
	flags |= GSS_C_DCE_STYLE | GSS_C_MUTUAL_FLAG;
	ap_options |= AP_OPTS_MUTUAL_REQUIRED;
    }
    if (req_flags & GSS_C_IDENTIFY_FLAG)
	flags |= GSS_C_IDENTIFY_FLAG;
    if (req_flags & GSS_C_EXTENDED_ERROR_FLAG)
	flags |= GSS_C_EXTENDED_ERROR_FLAG;

    flags |= GSS_C_CONF_FLAG;
    flags |= GSS_C_INTEG_FLAG;
    flags |= GSS_C_TRANS_FLAG;
    
    if (ret_flags)
	*ret_flags = flags;
    ctx->flags = flags;
    ctx->more_flags |= LOCAL;
    
    ret = _gsskrb5_create_8003_checksum (minor_status,
					 input_chan_bindings,
					 flags,
					 &fwd_data,
					 &cksum);
    krb5_data_free (&fwd_data);
    if (ret)
	goto failure;

    enctype = ctx->auth_context->keyblock->keytype;

    kret = krb5_build_authenticator (context,
				     ctx->auth_context,
				     enctype,
				     cred,
				     &cksum,
				     NULL,
				     &authenticator,
				     KRB5_KU_AP_REQ_AUTH);

    if (kret) {
	*minor_status = kret;
	ret = GSS_S_FAILURE;
	goto failure;
    }

    kret = krb5_build_ap_req (context,
			      enctype,
			      cred,
			      ap_options,
			      authenticator,
			      &outbuf);

    if (kret) {
	*minor_status = kret;
	ret = GSS_S_FAILURE;
	goto failure;
    }

    ret = _gsskrb5_encapsulate (minor_status, &outbuf, output_token,
				   (u_char *)"\x01\x00", GSS_KRB5_MECHANISM);
    if (ret)
	goto failure;

    krb5_data_free (&outbuf);
    krb5_free_creds(context, cred);
    free_Checksum(&cksum);
    if (initiator_cred_handle == NULL)
	krb5_cc_close(context, ccache);

    if (flags & GSS_C_MUTUAL_FLAG) {
	ctx->state = INITIATOR_WAIT_FOR_MUTAL;
	return GSS_S_CONTINUE_NEEDED;
    }

    return gsskrb5_initiator_ready(minor_status, ctx, context);
failure:
    if(cred)
	krb5_free_creds(context, cred);
    if (ccache && initiator_cred_handle == NULL)
	krb5_cc_close(context, ccache);

    return ret;

}

static OM_uint32
repl_mutual
(OM_uint32 * minor_status,
 gsskrb5_ctx ctx,
 krb5_context context,
 const gss_OID mech_type,
 OM_uint32 req_flags,
 OM_uint32 time_req,
 const gss_channel_bindings_t input_chan_bindings,
 const gss_buffer_t input_token,
 gss_OID * actual_mech_type,
 gss_buffer_t output_token,
 OM_uint32 * ret_flags,
 OM_uint32 * time_rec
    )
{
    OM_uint32 ret;
    krb5_error_code kret;
    krb5_data indata;
    krb5_ap_rep_enc_part *repl;
    int is_cfx = 0;

    output_token->length = 0;
    output_token->value = NULL;

    if (actual_mech_type)
	*actual_mech_type = GSS_KRB5_MECHANISM;

    if (ctx->flags & GSS_C_DCE_STYLE) {
	/* There is no OID wrapping. */
	indata.length	= input_token->length;
	indata.data	= input_token->value;
    } else {
	ret = _gsskrb5_decapsulate (minor_status,
				    input_token,
				    &indata,
				    "\x02\x00",
				    GSS_KRB5_MECHANISM);
	if (ret) {
	    /* XXX - Handle AP_ERROR */
	    return ret;
	}
    }

    kret = krb5_rd_rep (context,
			ctx->auth_context,
			&indata,
			&repl);
    if (kret) {
	*minor_status = kret;
	return GSS_S_FAILURE;
    }
    krb5_free_ap_rep_enc_part (context,
			       repl);
    
    _gsskrb5i_is_cfx(ctx, &is_cfx);
    if (is_cfx) {
	krb5_keyblock *key = NULL;

	kret = krb5_auth_con_getremotesubkey(context,
					     ctx->auth_context, 
					     &key);
	if (kret == 0 && key != NULL) {
    	    ctx->more_flags |= ACCEPTOR_SUBKEY;
	    krb5_free_keyblock (context, key);
	}
    }


    *minor_status = 0;
    if (time_rec) {
	ret = _gsskrb5_lifetime_left(minor_status,
				     context,
				     ctx->lifetime,
				     time_rec);
    } else {
	ret = GSS_S_COMPLETE;
    }
    if (ret_flags)
	*ret_flags = ctx->flags;

    if (req_flags & GSS_C_DCE_STYLE) {
	int32_t con_flags;
	krb5_data outbuf;

	/* Do don't do sequence number for the mk-rep */
	krb5_auth_con_removeflags(context,
				  ctx->auth_context,
				  KRB5_AUTH_CONTEXT_DO_SEQUENCE,
				  &con_flags);

	kret = krb5_mk_rep(context,
			   ctx->auth_context,
			   &outbuf);
	if (kret) {
	    *minor_status = kret;
	    return GSS_S_FAILURE;
	}
	
	output_token->length = outbuf.length;
	output_token->value  = outbuf.data;

	krb5_auth_con_removeflags(context,
				  ctx->auth_context,
				  KRB5_AUTH_CONTEXT_DO_SEQUENCE,
				  NULL);
    }

    return gsskrb5_initiator_ready(minor_status, ctx, context);
}

/*
 * gss_init_sec_context
 */

OM_uint32 _gsskrb5_init_sec_context
(OM_uint32 * minor_status,
 const gss_cred_id_t initiator_cred_handle,
 gss_ctx_id_t * context_handle,
 const gss_name_t target_name,
 const gss_OID mech_type,
 OM_uint32 req_flags,
 OM_uint32 time_req,
 const gss_channel_bindings_t input_chan_bindings,
 const gss_buffer_t input_token,
 gss_OID * actual_mech_type,
 gss_buffer_t output_token,
 OM_uint32 * ret_flags,
 OM_uint32 * time_rec
    )
{
    krb5_context context;
    gsskrb5_cred cred = (gsskrb5_cred)initiator_cred_handle;
    krb5_const_principal name = (krb5_const_principal)target_name;
    gsskrb5_ctx ctx;
    OM_uint32 ret;

    GSSAPI_KRB5_INIT (&context);

    output_token->length = 0;
    output_token->value  = NULL;

    if (context_handle == NULL) {
	*minor_status = 0;
	return GSS_S_FAILURE | GSS_S_CALL_BAD_STRUCTURE;
    }

    if (ret_flags)
	*ret_flags = 0;
    if (time_rec)
	*time_rec = 0;

    if (target_name == GSS_C_NO_NAME) {
	if (actual_mech_type)
	    *actual_mech_type = GSS_C_NO_OID;
	*minor_status = 0;
	return GSS_S_BAD_NAME;
    }

    if (mech_type != GSS_C_NO_OID && 
	!gss_oid_equal(mech_type, GSS_KRB5_MECHANISM))
	return GSS_S_BAD_MECH;

    if (input_token == GSS_C_NO_BUFFER || input_token->length == 0) {
	OM_uint32 ret;

	if (*context_handle != GSS_C_NO_CONTEXT) {
	    *minor_status = 0;
	    return GSS_S_FAILURE | GSS_S_CALL_BAD_STRUCTURE;
	}
    
	ret = _gsskrb5_create_ctx(minor_status,
				  context_handle,
				  context,
				  input_chan_bindings,
				  INITIATOR_START);
	if (ret)
	    return ret;
    }

    if (*context_handle == GSS_C_NO_CONTEXT) {
	*minor_status = 0;
	return GSS_S_FAILURE | GSS_S_CALL_BAD_STRUCTURE;
    }

    ctx = (gsskrb5_ctx) *context_handle;

    HEIMDAL_MUTEX_lock(&ctx->ctx_id_mutex);

    switch (ctx->state) {
    case INITIATOR_START:
	ret = init_auth(minor_status,
			cred,
			ctx,
			context,
			name,
			mech_type,
			req_flags,
			time_req,
			input_chan_bindings,
			input_token,
			actual_mech_type,
			output_token,
			ret_flags,
			time_rec);
	break;
    case INITIATOR_WAIT_FOR_MUTAL:
	ret = repl_mutual(minor_status,
			  ctx,
			  context,
			  mech_type,
			  req_flags,
			  time_req,
			  input_chan_bindings,
			  input_token,
			  actual_mech_type,
			  output_token,
			  ret_flags,
			  time_rec);
	break;
    case INITIATOR_READY:
	/* 
	 * If we get there, the caller have called
	 * gss_init_sec_context() one time too many.
	 */
	*minor_status = 0;
	ret = GSS_S_BAD_STATUS;
	break;
    default:
	*minor_status = 0;
	ret = GSS_S_BAD_STATUS;
	break;
    }
    HEIMDAL_MUTEX_unlock(&ctx->ctx_id_mutex);

    /* destroy context in case of error */
    if (GSS_ERROR(ret)) {
	OM_uint32 min2;
	_gsskrb5_delete_sec_context(&min2, context_handle, GSS_C_NO_BUFFER);
    }

    return ret;

}