/*
   Unix SMB/CIFS implementation.
   dump the remote SAM using rpc samsync operations

   Copyright (C) Guenther Deschner 2008.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "includes.h"
#include "libnet/libnet.h"

#ifdef HAVE_KRB5

/****************************************************************
****************************************************************/

static int keytab_close(struct libnet_keytab_context *ctx)
{
	if (!ctx) {
		return 0;
	}

	if (ctx->keytab && ctx->context) {
		krb5_kt_close(ctx->context, ctx->keytab);
	}

	if (ctx->context) {
		krb5_free_context(ctx->context);
	}

	if (ctx->ads) {
		ads_destroy(&ctx->ads);
	}

	TALLOC_FREE(ctx);

	return 0;
}

/****************************************************************
****************************************************************/

krb5_error_code libnet_keytab_init(TALLOC_CTX *mem_ctx,
				   const char *keytab_name,
				   struct libnet_keytab_context **ctx)
{
	krb5_error_code ret = 0;
	krb5_context context = NULL;
	krb5_keytab keytab = NULL;
	const char *keytab_string = NULL;

	struct libnet_keytab_context *r;

	r = TALLOC_ZERO_P(mem_ctx, struct libnet_keytab_context);
	if (!r) {
		return ENOMEM;
	}

	talloc_set_destructor(r, keytab_close);

	initialize_krb5_error_table();
	ret = krb5_init_context(&context);
	if (ret) {
		DEBUG(1,("keytab_init: could not krb5_init_context: %s\n",
			error_message(ret)));
		return ret;
	}

	ret = smb_krb5_open_keytab(context, keytab_name, true, &keytab);
	if (ret) {
		DEBUG(1,("keytab_init: smb_krb5_open_keytab failed (%s)\n",
			error_message(ret)));
		krb5_free_context(context);
		return ret;
	}

	ret = smb_krb5_keytab_name(mem_ctx, context, keytab, &keytab_string);
	if (ret) {
		krb5_kt_close(context, keytab);
		krb5_free_context(context);
		return ret;
	}

	r->context = context;
	r->keytab = keytab;
	r->keytab_name = keytab_string;

	*ctx = r;

	return 0;
}

/****************************************************************
****************************************************************/

krb5_error_code libnet_keytab_add(struct libnet_keytab_context *ctx)
{
#if defined(ENCTYPE_ARCFOUR_HMAC)
	krb5_error_code ret = 0;
	krb5_enctype enctypes[2] = { ENCTYPE_ARCFOUR_HMAC, 0 };
	int i;

	for (i=0; i<ctx->count; i++) {

		struct libnet_keytab_entry *entry = &ctx->entries[i];
		krb5_data password;

		password.data = (char *)entry->password.data;
		password.length = entry->password.length;

		ret = smb_krb5_kt_add_entry_ext(ctx->context,
						ctx->keytab,
						entry->kvno,
						entry->principal,
						enctypes,
						password,
						true,
						true);
		if (ret) {
			DEBUG(1,("libnet_keytab_add: "
				"Failed to add entry to keytab file\n"));
			return ret;
		}
	}

	return ret;
#else
	return -1;
#endif /* defined(ENCTYPE_ARCFOUR_HMAC) */
}

struct libnet_keytab_entry *libnet_keytab_search(struct libnet_keytab_context *ctx,
						 const char *principal,
						 int kvno,
						 const krb5_enctype enctype,
						 TALLOC_CTX *mem_ctx)
{
	krb5_error_code ret = 0;
	krb5_kt_cursor cursor;
	krb5_keytab_entry kt_entry;
	struct libnet_keytab_entry *entry = NULL;

	ZERO_STRUCT(kt_entry);
	ZERO_STRUCT(cursor);

	ret = krb5_kt_start_seq_get(ctx->context, ctx->keytab, &cursor);
	if (ret) {
		return NULL;
	}

	while (krb5_kt_next_entry(ctx->context, ctx->keytab, &kt_entry, &cursor) == 0)
	{
		char *princ_s = NULL;

		if (kt_entry.vno != kvno) {
			goto cont;
		}

		if (kt_entry.key.enctype != enctype) {
			goto cont;
		}

		ret = smb_krb5_unparse_name(ctx->context, kt_entry.principal,
					    &princ_s);
		if (ret) {
			goto cont;
		}

		if (strcmp(principal, princ_s) != 0) {
			goto cont;
		}

		entry = talloc_zero(mem_ctx, struct libnet_keytab_entry);
		if (!entry) {
			goto fail;
		}

		entry->name = talloc_strdup(entry, princ_s);
		if (!entry->name) {
			goto fail;
		}

		entry->principal = talloc_strdup(entry, princ_s);
		if (!entry->principal) {
			goto fail;
		}

		entry->password = data_blob_talloc(entry, kt_entry.key.contents,
						   kt_entry.key.length);
		if (!entry->password.data) {
			goto fail;
		}

		smb_krb5_kt_free_entry(ctx->context, &kt_entry);
		SAFE_FREE(princ_s);
		break;

fail:
		smb_krb5_kt_free_entry(ctx->context, &kt_entry);
		SAFE_FREE(princ_s);
		TALLOC_FREE(entry);
		break;

cont:
		smb_krb5_kt_free_entry(ctx->context, &kt_entry);
		SAFE_FREE(princ_s);
		continue;
	}

	krb5_kt_end_seq_get(ctx->context, ctx->keytab, &cursor);
	return entry;
}

/**
 * Remove all entries that have the given principal, kvno and enctype.
 */
krb5_error_code libnet_keytab_remove_entries(struct libnet_keytab_context *ctx,
					     const char *principal,
					     int kvno,
					     const krb5_enctype enctype)
{
	krb5_error_code ret;
	krb5_kt_cursor cursor;
	krb5_keytab_entry kt_entry;

	ZERO_STRUCT(kt_entry);
	ZERO_STRUCT(cursor);

	ret = krb5_kt_start_seq_get(ctx->context, ctx->keytab, &cursor);
	if (ret) {
		return 0;
	}

	while (krb5_kt_next_entry(ctx->context, ctx->keytab, &kt_entry, &cursor) == 0)
	{
		char *princ_s = NULL;

		if (kt_entry.vno != kvno) {
			goto cont;
		}

		if (kt_entry.key.enctype != enctype) {
			goto cont;
		}

		ret = smb_krb5_unparse_name(ctx->context, kt_entry.principal,
					    &princ_s);
		if (ret) {
			DEBUG(5, ("smb_krb5_unparse_name failed (%s)\n",
				  error_message(ret)));
			goto cont;
		}

		if (strcmp(principal, princ_s) != 0) {
			goto cont;
		}

		/* match found - remove */

		DEBUG(10, ("found entry for principal %s, kvno %d, "
			   "enctype %d - trying to remove it\n",
			   princ_s, kt_entry.vno, kt_entry.key.enctype));

		ret = krb5_kt_end_seq_get(ctx->context, ctx->keytab, &cursor);
		ZERO_STRUCT(cursor);
		if (ret) {
			DEBUG(5, ("krb5_kt_end_seq_get failed (%s)\n",
				  error_message(ret)));
			goto cont;
		}

		ret = krb5_kt_remove_entry(ctx->context, ctx->keytab,
					   &kt_entry);
		if (ret) {
			DEBUG(5, ("krb5_kt_remove_entry failed (%s)\n",
				  error_message(ret)));
			goto cont;
		}
		DEBUG(10, ("removed entry for principal %s, kvno %d, "
			   "enctype %d\n", princ_s, kt_entry.vno,
			   kt_entry.key.enctype));

		ret = krb5_kt_start_seq_get(ctx->context, ctx->keytab, &cursor);
		if (ret) {
			DEBUG(5, ("krb5_kt_start_seq_get failed (%s)\n",
				  error_message(ret)));
			goto cont;
		}

cont:
		smb_krb5_kt_free_entry(ctx->context, &kt_entry);
		SAFE_FREE(princ_s);
	}

	ret = krb5_kt_end_seq_get(ctx->context, ctx->keytab, &cursor);
	if (ret) {
		DEBUG(5, ("krb5_kt_end_seq_get failed (%s)\n",
			  error_message(ret)));
	}

	return ret;
}

#endif /* HAVE_KRB5 */