/*
 * Portions Copyright (C) 2004  Internet Systems Consortium, Inc. ("ISC")
 * Portions Copyright (C) 1999-2002  Internet Software Consortium.
 * Portions Copyright (C) 1995-2000 by Network Associates, Inc.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC AND NETWORK ASSOCIATES DISCLAIMS
 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE
 * FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
 * IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

/*
 * Principal Author: Brian Wellington
 * $Id: dst_parse.c,v 1.1.4.1 2004/12/09 04:07:17 marka Exp $
 */

#include <config.h>

#include <isc/base64.h>
#include <isc/dir.h>
#include <isc/fsaccess.h>
#include <isc/lex.h>
#include <isc/mem.h>
#include <isc/string.h>
#include <isc/util.h>

#include "dst_internal.h"
#include "dst_parse.h"
#include "dst/result.h"

#define DST_AS_STR(t) ((t).value.as_textregion.base)

#define PRIVATE_KEY_STR "Private-key-format:"
#define ALGORITHM_STR "Algorithm:"

struct parse_map {
	const int value;
	const char *tag;
};

static struct parse_map map[] = {
	{TAG_RSA_MODULUS, "Modulus:"},
	{TAG_RSA_PUBLICEXPONENT, "PublicExponent:"},
	{TAG_RSA_PRIVATEEXPONENT, "PrivateExponent:"},
	{TAG_RSA_PRIME1, "Prime1:"},
	{TAG_RSA_PRIME2, "Prime2:"},
	{TAG_RSA_EXPONENT1, "Exponent1:"},
	{TAG_RSA_EXPONENT2, "Exponent2:"},
	{TAG_RSA_COEFFICIENT, "Coefficient:"},

	{TAG_DH_PRIME, "Prime(p):"},
	{TAG_DH_GENERATOR, "Generator(g):"},
	{TAG_DH_PRIVATE, "Private_value(x):"},
	{TAG_DH_PUBLIC, "Public_value(y):"},

	{TAG_DSA_PRIME, "Prime(p):"},
	{TAG_DSA_SUBPRIME, "Subprime(q):"},
	{TAG_DSA_BASE, "Base(g):"},
	{TAG_DSA_PRIVATE, "Private_value(x):"},
	{TAG_DSA_PUBLIC, "Public_value(y):"},

	{TAG_HMACMD5_KEY, "Key:"},
	{0, NULL}
};

static int
find_value(const char *s, const unsigned int alg) {
	int i;

	for (i = 0; ; i++) {
		if (map[i].tag == NULL)
			return (-1);
		else if (strcasecmp(s, map[i].tag) == 0 &&
			 TAG_ALG(map[i].value) == alg)
			return (map[i].value);
	}
}

static const char *
find_tag(const int value) {
	int i;

	for (i = 0; ; i++) {
		if (map[i].tag == NULL)
			return (NULL);
		else if (value == map[i].value)
			return (map[i].tag);
	}
}

static int
check_rsa(const dst_private_t *priv) {
	int i, j;
	if (priv->nelements != RSA_NTAGS)
		return (-1);
	for (i = 0; i < RSA_NTAGS; i++) {
		for (j = 0; j < priv->nelements; j++)
			if (priv->elements[j].tag == TAG(DST_ALG_RSAMD5, i))
				break;
		if (j == priv->nelements)
			return (-1);
	}
	return (0);
}

static int
check_dh(const dst_private_t *priv) {
	int i, j;
	if (priv->nelements != DH_NTAGS)
		return (-1);
	for (i = 0; i < DH_NTAGS; i++) {
		for (j = 0; j < priv->nelements; j++)
			if (priv->elements[j].tag == TAG(DST_ALG_DH, i))
				break;
		if (j == priv->nelements)
			return (-1);
	}
	return (0);
}

static int
check_dsa(const dst_private_t *priv) {
	int i, j;
	if (priv->nelements != DSA_NTAGS)
		return (-1);
	for (i = 0; i < DSA_NTAGS; i++) {
		for (j = 0; j < priv->nelements; j++)
			if (priv->elements[j].tag == TAG(DST_ALG_DSA, i))
				break;
		if (j == priv->nelements)
			return (-1);
	}
	return (0);
}

static int
check_hmac_md5(const dst_private_t *priv) {
	if (priv->nelements != HMACMD5_NTAGS)
		return (-1);
	if (priv->elements[0].tag != TAG_HMACMD5_KEY)
		return (-1);
	return (0);
}

static int
check_data(const dst_private_t *priv, const unsigned int alg) {
	/* XXXVIX this switch statement is too sparse to gen a jump table. */
	switch (alg) {
	case DST_ALG_RSAMD5:
	case DST_ALG_RSASHA1:
		return (check_rsa(priv));
	case DST_ALG_DH:
		return (check_dh(priv));
	case DST_ALG_DSA:
		return (check_dsa(priv));
	case DST_ALG_HMACMD5:
		return (check_hmac_md5(priv));
	default:
		return (DST_R_UNSUPPORTEDALG);
	}
}

void
dst__privstruct_free(dst_private_t *priv, isc_mem_t *mctx) {
	int i;

	if (priv == NULL)
		return;
	for (i = 0; i < priv->nelements; i++) {
		if (priv->elements[i].data == NULL)
			continue;
		memset(priv->elements[i].data, 0, MAXFIELDSIZE);
		isc_mem_put(mctx, priv->elements[i].data, MAXFIELDSIZE);
	}
	priv->nelements = 0;
}

int
dst__privstruct_parse(dst_key_t *key, unsigned int alg, isc_lex_t *lex,
		      isc_mem_t *mctx, dst_private_t *priv)
{
	int n = 0, major, minor;
	isc_buffer_t b;
	isc_token_t token;
	unsigned char *data = NULL;
	unsigned int opt = ISC_LEXOPT_EOL;
	isc_result_t ret;

	REQUIRE(priv != NULL);

	priv->nelements = 0;

#define NEXTTOKEN(lex, opt, token)				\
	do {							\
		ret = isc_lex_gettoken(lex, opt, token);	\
		if (ret != ISC_R_SUCCESS)			\
			goto fail;				\
	} while (0)

#define READLINE(lex, opt, token)				\
	do {							\
		ret = isc_lex_gettoken(lex, opt, token);	\
		if (ret == ISC_R_EOF)				\
			break;					\
		else if (ret != ISC_R_SUCCESS)			\
			goto fail;				\
	} while ((*token).type != isc_tokentype_eol)

	/*
	 * Read the description line.
	 */
	NEXTTOKEN(lex, opt, &token);
	if (token.type != isc_tokentype_string ||
	    strcmp(DST_AS_STR(token), PRIVATE_KEY_STR) != 0)
	{
		ret = DST_R_INVALIDPRIVATEKEY;
		goto fail;
	}

	NEXTTOKEN(lex, opt, &token);
	if (token.type != isc_tokentype_string ||
	    (DST_AS_STR(token))[0] != 'v')
	{
		ret = DST_R_INVALIDPRIVATEKEY;
		goto fail;
	}
	if (sscanf(DST_AS_STR(token), "v%d.%d", &major, &minor) != 2)
	{
		ret = DST_R_INVALIDPRIVATEKEY;
		goto fail;
	}

	if (major > MAJOR_VERSION ||
	    (major == MAJOR_VERSION && minor > MINOR_VERSION))
	{
		ret = DST_R_INVALIDPRIVATEKEY;
		goto fail;
	}

	READLINE(lex, opt, &token);

	/*
	 * Read the algorithm line.
	 */
	NEXTTOKEN(lex, opt, &token);
	if (token.type != isc_tokentype_string ||
	    strcmp(DST_AS_STR(token), ALGORITHM_STR) != 0)
	{
		ret = DST_R_INVALIDPRIVATEKEY;
		goto fail;
	}

	NEXTTOKEN(lex, opt | ISC_LEXOPT_NUMBER, &token);
	if (token.type != isc_tokentype_number ||
	    token.value.as_ulong != (unsigned long) dst_key_alg(key))
	{
		ret = DST_R_INVALIDPRIVATEKEY;
		goto fail;
	}

	READLINE(lex, opt, &token);

	/*
	 * Read the key data.
	 */
	for (n = 0; n < MAXFIELDS; n++) {
		int tag;
		isc_region_t r;

		do {
			ret = isc_lex_gettoken(lex, opt, &token);
			if (ret == ISC_R_EOF)
				goto done;
			if (ret != ISC_R_SUCCESS)
				goto fail;
		} while (token.type == isc_tokentype_eol);

		if (token.type != isc_tokentype_string) {
			ret = DST_R_INVALIDPRIVATEKEY;
			goto fail;
		}

		memset(&priv->elements[n], 0, sizeof(dst_private_element_t));
		tag = find_value(DST_AS_STR(token), alg);
		if (tag < 0 || TAG_ALG(tag) != alg) {
			ret = DST_R_INVALIDPRIVATEKEY;
			goto fail;
		}
		priv->elements[n].tag = tag;

		data = (unsigned char *) isc_mem_get(mctx, MAXFIELDSIZE);
		if (data == NULL)
			goto fail;

		isc_buffer_init(&b, data, MAXFIELDSIZE);
		ret = isc_base64_tobuffer(lex, &b, -1);
		if (ret != ISC_R_SUCCESS)
			goto fail;
		isc_buffer_usedregion(&b, &r);
		priv->elements[n].length = r.length;
		priv->elements[n].data = r.base;

		READLINE(lex, opt, &token);
		data = NULL;
	}
 done:
	priv->nelements = n;

	if (check_data(priv, alg) < 0)
		goto fail;

	return (ISC_R_SUCCESS);

fail:
	priv->nelements = n;
	dst__privstruct_free(priv, mctx);
	if (data != NULL)
		isc_mem_put(mctx, data, MAXFIELDSIZE);

	return (ret);
}

int
dst__privstruct_writefile(const dst_key_t *key, const dst_private_t *priv,
			  const char *directory)
{
	FILE *fp;
	int ret, i;
	isc_result_t iret;
	char filename[ISC_DIR_NAMEMAX];
	char buffer[MAXFIELDSIZE * 2];
	isc_buffer_t b;
	isc_fsaccess_t access;

	REQUIRE(priv != NULL);

	if (check_data(priv, dst_key_alg(key)) < 0)
		return (DST_R_INVALIDPRIVATEKEY);

	isc_buffer_init(&b, filename, sizeof(filename));
	ret = dst_key_buildfilename(key, DST_TYPE_PRIVATE, directory, &b);
	if (ret != ISC_R_SUCCESS)
		return (ret);

	if ((fp = fopen(filename, "w")) == NULL)
		return (DST_R_WRITEERROR);

	access = 0;
	isc_fsaccess_add(ISC_FSACCESS_OWNER,
			 ISC_FSACCESS_READ | ISC_FSACCESS_WRITE,
			 &access);
	(void)isc_fsaccess_set(filename, access);

	/* XXXDCL return value should be checked for full filesystem */
	fprintf(fp, "%s v%d.%d\n", PRIVATE_KEY_STR, MAJOR_VERSION,
		MINOR_VERSION);

	fprintf(fp, "%s %d ", ALGORITHM_STR, dst_key_alg(key));
	/* XXXVIX this switch statement is too sparse to gen a jump table. */
	switch (dst_key_alg(key)) {
	case DST_ALG_RSAMD5:
		fprintf(fp, "(RSA)\n");
		break;
	case DST_ALG_DH:
		fprintf(fp, "(DH)\n");
		break;
	case DST_ALG_DSA:
		fprintf(fp, "(DSA)\n");
		break;
	case DST_ALG_RSASHA1:
		fprintf(fp, "(RSASHA1)\n");
		break;
	case DST_ALG_HMACMD5:
		fprintf(fp, "(HMAC_MD5)\n");
		break;
	default:
		fprintf(fp, "(?)\n");
		break;
	}

	for (i = 0; i < priv->nelements; i++) {
		isc_buffer_t b;
		isc_region_t r;
		const char *s;

		s = find_tag(priv->elements[i].tag);

		r.base = priv->elements[i].data;
		r.length = priv->elements[i].length;
		isc_buffer_init(&b, buffer, sizeof(buffer));
		iret = isc_base64_totext(&r, sizeof(buffer), "", &b);
		if (iret != ISC_R_SUCCESS) {
			fclose(fp);
			return (DST_R_INVALIDPRIVATEKEY);
		}
		isc_buffer_usedregion(&b, &r);

		fprintf(fp, "%s ", s);
		fwrite(r.base, 1, r.length, fp);
		fprintf(fp, "\n");
	}

	fclose(fp);
	return (ISC_R_SUCCESS);
}