/*************************************************************************
 * (C) 2011 AITNET - Sofia/Bulgaria - <office@aitbg.com>
 *  by Michael Pounov <misho@aitbg.com>
 *
 * $Author: misho $
 * $Id: voucher.c,v 1.3 2014/02/05 15:44:06 misho Exp $
 *
 *************************************************************************
The ELWIX and AITNET software is distributed under the following
terms:

All of the documentation and software included in the ELWIX and AITNET
Releases is copyrighted by ELWIX - Sofia/Bulgaria <info@elwix.org>

Copyright 2004 - 2014
	by Michael Pounov <misho@elwix.org>.  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. All advertising materials mentioning features or use of this software
   must display the following acknowledgement:
This product includes software developed by Michael Pounov <misho@elwix.org>
ELWIX - Embedded LightWeight unIX and its contributors.
4. Neither the name of AITNET 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 AITNET 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 REGENTS 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 "global.h"
#include <openssl/pem.h>
#include <openssl/rsa.h>
#include <openssl/err.h>


cfg_root_t cfg;
array_t *vs;
FILE *output;
int Verbose;
char szConfig[MAXPATHLEN] = VOUCHER_CFG;
extern char compiled[], compiledby[], compilehost[];


static void
Usage()
{
	printf(	" -= VOUCHER =- management tool\n"
		"=== %s === %s@%s ===\n\n"
		"Syntax: voucher [options] -r <RollID> [count]\n"
		"\tvoucher [options] -t <voucher> [voucher [voucher ...]]\n\n"
		"\t-v\t\tVerbose (more -v more verbosity)\n"
		"\t-r\t\tRequest new voucher(s) mode\n"
		"\t-t\t\tTest voucher(s) mode\n"
		"\t-g\t\tRequest new RSA pair mode\n"
		"\t-c <config>\tConfig file\n"
		"\t-o <output>\tOutput file [default=-]\n"
		"\n", compiled, compiledby, compilehost);
}

static void
AtExit()
{
	ait_freeVars(&vs);
	if (output != stdout)
		fclose(output);
}

static inline int
RedirOutput(const char *name)
{
	AtExit();

	if (strcmp(name, "-")) {
		output = fopen(name, "w+");
		if (!output) {
			printf("Error:: can't redirect output #%d - %s\n", 
					errno, strerror(errno));
			return -1;
		}
	} else
		output = stdout;
	return 0;
}

static int
NewRSA()
{
	RSA *k = RSA_generate_key(VOUCHER_MAX_RSA * 8, 65537, NULL, NULL);
	if (!k) {
		printf("Error:: can't generate RSA key\n");
		return 2;
	}

	PEM_write_RSAPrivateKey(output, k, NULL, NULL, 0, NULL, NULL);
	PEM_write_RSA_PUBKEY(output, k);
	return 0;
}

static RSA *
LoadKey(char mode)
{
	FILE *f;
	RSA *key = NULL;
	ait_val_t v;

#ifndef NDEBUG
	ERR_load_crypto_strings();
#endif

	AIT_INIT_VAL(&v);
	if (mode == 1)
		cfg_loadAttribute(&cfg, "voucher", "key_private", &v, VOUCHER_KEY);
	else
		cfg_loadAttribute(&cfg, "voucher", "key_public", &v, VOUCHER_CRT);

	f = fopen(AIT_GET_STR(&v), "r");
	AIT_FREE_VAL(&v);
	if (!f) {
		printf("Error:: open key #%d - %s\n", errno, strerror(errno));
		return NULL;
	}

	if (mode == 1)
		key = PEM_read_RSAPrivateKey(f, NULL, NULL, NULL);
	else
		key = PEM_read_RSA_PUBKEY(f, NULL, NULL, NULL);

	fclose(f);

	if (!key)
		printf("Error:: wrong key !!!\n");
	return key;
}

static void
ShowConfig(char mode, int rid, int cnt)
{
	register int i;

	if (mode == 1)
		printf(">>> Request voucher ticket(s) %d for Roll %d\n", cnt, rid);
	else
		printf(">>> Test voucher ticket(s) %d\n", cnt);

	for (i = 0; i < array_Size(vs); i++)
		printf(" + Voucher[%d]= %s\n", i, AIT_GET_STR(ait_getVars(&vs, i)));
	printf(" + Roll ID %d bits\n", (int) 
			strtol(cfg_getAttribute(&cfg, "voucher", "rollbits"), NULL, 0));
	printf(" + Ticket ID %d bits\n", (int) 
			strtol(cfg_getAttribute(&cfg, "voucher", "ticketbits"), NULL, 0));
	printf(" + CheckSum %d bits\n", (int) 
			strtol(cfg_getAttribute(&cfg, "voucher", "cksumbits"), NULL, 0));
	printf(" + Magic 0x%llx\n", (uint64_t) 
			strtoll(cfg_getAttribute(&cfg, "voucher", "magic"), NULL, 0));
	printf(" + Charset %s\n", cfg_getAttribute(&cfg, "voucher", "charset"));
	if (!cfg_getAttribute(&cfg, "voucher", "key_private"))
		cfg_setAttribute(&cfg, "voucher", "key_private", VOUCHER_KEY);
	printf(" + Private key %s\n", cfg_getAttribute(&cfg, "voucher", "key_private"));
	if (!cfg_getAttribute(&cfg, "voucher", "key_public"))
		cfg_setAttribute(&cfg, "voucher", "key_public", VOUCHER_CRT);
	printf(" + Public key %s\n", cfg_getAttribute(&cfg, "voucher", "key_public"));
}

static int
CheckConfig(char mode, int rid, int cnt)
{
	const char *str;

	str = cfg_getAttribute(&cfg, "voucher", "charset");
	if (!str || strlen(str) < 2) {
		printf("Error:: charset too short ... '%s'\n", str);
		return -1;
	}
	if (strtol(cfg_getAttribute(&cfg, "voucher", "rollbits"), NULL, 0) > 31 || 
			strtol(cfg_getAttribute(&cfg, "voucher", "ticketbits"), NULL, 0) > 31 || 
			strtol(cfg_getAttribute(&cfg, "voucher", "cksumbits"), NULL, 0) > 31) {
		printf("Error:: bits must be between 1..31\n");
		return -1;
	}
	if (mode == 1) {
		if (rid >= 1LL << strtol(cfg_getAttribute(&cfg, "voucher", "rollbits"), NULL, 0)) {
			printf("Error:: Roll bits must be 0..%lu\n", 
					strtol(cfg_getAttribute(&cfg, "voucher", "rollbits"), NULL, 0));
			return -1;
		}
		if (cnt < 1 || cnt >= 1LL << strtol(cfg_getAttribute(&cfg, "voucher", "ticketbits"), NULL, 0)) {
			printf("Error:: Ticket bits count must be 1..%lu\n", 
					strtol(cfg_getAttribute(&cfg, "voucher", "ticketbits"), NULL, 0));
			return -1;
		}
	}

	return 0;
}

static inline void
ll2buf(uint64_t ll, u_char * __restrict buf, int len)
{
	register int i;

	for (i = len - 1; i >= 0; i--) {
		buf[i] = ll & 0xff;
		ll >>= 8;
	}
}

static inline void
buf2ll(u_char * __restrict buf, uint64_t * __restrict ll, int len)
{
	register int i;

	for (i = 1, *ll = buf[0]; i < len; i++) {
		*ll <<= 8;
		*ll += buf[i];
	}
}

static int
ComputeVouchers(int rid, int cnt, RSA * __restrict key)
{
	int base, clen, alen;
	u_int roll, ticket, cksum, mb;
	uint64_t clrcode, code, magic;
	register int i, num;
	const char *charset;
	u_char clrbuf[VOUCHER_MAX_RSA], codebuf[VOUCHER_MAX_LEN], *p = codebuf;

	/* prepare vars */
	roll = strtol(cfg_getAttribute(&cfg, "voucher", "rollbits"), NULL, 0);
	ticket = strtol(cfg_getAttribute(&cfg, "voucher", "ticketbits"), NULL, 0);
	cksum = strtol(cfg_getAttribute(&cfg, "voucher", "cksumbits"), NULL, 0);

	magic = strtoll(cfg_getAttribute(&cfg, "voucher", "magic"), NULL, 0);

	charset = cfg_getAttribute(&cfg, "voucher", "charset");
	base = strlen(charset);
	clen = RSA_size(key);
	alen = clen < sizeof(clrcode) ? clen : sizeof(clrcode);
	if (((roll + ticket + cksum) >> 3) + 1 > alen) {
		printf("Error: roll+ticket+cksum bits too large for given key\n");
		return -1;
	}

	mb = alen * 8 - (roll + ticket + cksum + 1);
	if (mb > 0)
		magic &= (1LL << mb) - 1;
	else {
		mb ^= mb;
		magic ^= magic;
	}

	for (i = 1; i <= cnt; i++) {
		clrcode = magic << cksum;
		clrcode += (rid + i) % (1 << cksum);
		clrcode <<= ticket;
		clrcode += i;
		clrcode = (clrcode << roll) + rid;
		clrcode &= 0xffffffffffffffffLL >> (65 - 8 * clen);

		ll2buf(clrcode, clrbuf, clen);

		if (RSA_private_encrypt(clen, clrbuf, codebuf, key, RSA_NO_PADDING) == -1) {
			printf("Error:: ticket[%d] RSA private encrypt %s\n", i, 
					ERR_error_string(ERR_get_error(), NULL));
			continue;
		}

		buf2ll(codebuf, &code, clen);

		/* pretty print */
		memset(codebuf, 0, sizeof codebuf);
		for (p = codebuf, num = sizeof codebuf; code && num; num--) {
			*p++ = charset[code % base];
			code /= base;
		}
		if (code) {
			printf("Error:: voucher gets too long ... (%llu)\n", code);
			continue;
		}

		printf("Voucher[%d]= %s\n", i, codebuf);
	}

	return 0;
}

static int
TestVouchers(array_t * __restrict v, RSA * __restrict key)
{
	int base, clen, alen;
	u_int roll, ticket, cksum, mb;
	uint64_t clrcode, code, magic;
	register int i, checksum, rid, cnt;
	const char *charset, *voucher;
	u_char clrbuf[VOUCHER_MAX_RSA], codebuf[VOUCHER_MAX_LEN], *p, *s;

	/* prepare vars */
	roll = strtol(cfg_getAttribute(&cfg, "voucher", "rollbits"), NULL, 0);
	ticket = strtol(cfg_getAttribute(&cfg, "voucher", "ticketbits"), NULL, 0);
	cksum = strtol(cfg_getAttribute(&cfg, "voucher", "cksumbits"), NULL, 0);

	magic = strtoll(cfg_getAttribute(&cfg, "voucher", "magic"), NULL, 0);

	charset = cfg_getAttribute(&cfg, "voucher", "charset");
	base = strlen(charset);
	clen = RSA_size(key);
	alen = clen < sizeof(clrcode) ? clen : sizeof(clrcode);
	if (((roll + ticket + cksum) >> 3) + 1 > alen) {
		printf("Error: roll+ticket+cksum bits too large for given key\n");
		return -1;
	}

	mb = alen * 8 - (roll + ticket + cksum + 1);
	if (mb > 0)
		magic &= (1LL << mb) - 1;
	else {
		mb ^= mb;
		magic ^= magic;
	}

	for (i = 0, code = 0; i < array_Size(v); i++, code = 0) {
		voucher = AIT_GET_STR(ait_getVars((array_t**) &v, i));

		/* convert from voucher string to number */
		p = (u_char*) strrchr(voucher, '\0'); 
		while (p > (u_char*) voucher) {
			p--;
			if (*p == ' ')
				break;
			code *= base;
			s = (u_char*) strchr(charset, *p);
			if (!s) {
				VERB(1) printf("Error:: illegal character (%c) found in %s\n", 
						*p, voucher);
				printf("Ticket[%d] = %s \"%s\"\n", i, VOUCHER_ERR, voucher);
				break;
			}
			code += (s - (u_char*) charset);
		}

		ll2buf(code, codebuf, clen);

		if (RSA_public_decrypt(clen, codebuf, clrbuf, key, RSA_NO_PADDING) == -1) {
			VERB(1) printf("Error:: ticket[%d] RSA decrypt failed %s\n", i, 
					ERR_error_string(ERR_get_error(), NULL));
			printf("Ticket[%d] = %s \"%s\"\n", i, VOUCHER_ERR, voucher);
			continue;
		}

		buf2ll(clrbuf, &clrcode, clen);

		rid = clrcode & ((1 << roll) - 1);
		cnt = (clrcode >> roll) & ((1 << ticket) - 1);
		checksum = (clrcode >> (ticket + roll)) & ((1 << cksum) - 1);
		if (magic != ((clrcode >> (roll + ticket + cksum)))) {
			VERB(1) printf("Error:: ticket[%d] invalid magic\n", i);
			printf("Ticket[%d] = %s \"%s\"\n", i, VOUCHER_ERR, voucher);
			continue;
		}
		if ((cnt + rid) % (1L << cksum) != checksum) {
			VERB(1) printf("Error:: ticket[%d] invalid checksum\n", i);
			printf("Ticket[%d] = %s \"%s\"\n", i, VOUCHER_ERR, voucher);
			continue;
		}

		printf("Ticket[%d] = %s \"%s\" %d %d\n", i, VOUCHER_OK, voucher, rid, cnt);
	}

	return 0;
}


int
main(int argc, char **argv)
{
	char ch, mode = 0;
	int rid = 0, cnt = 1;
	register int i;
	RSA *key;

	output = stdout;
	atexit(AtExit);

#ifdef __NetBSD__
	srandom(getpid() ^ time(NULL));
#else
	srandomdev();
#endif

	while ((ch = getopt(argc, argv, "hvrtgc:o:")) != -1)
		switch (ch) {
			case 'r':
				mode = 1;
				break;
			case 't':
				mode = 2;
				break;
			case 'g':
				return NewRSA();
			case 'c':
				strlcpy(szConfig, optarg, sizeof szConfig);
				break;
			case 'o':
				RedirOutput(optarg);
				break;
			case 'v':
				Verbose++;
				break;
			case 'h':
			default:
				Usage();
				return 1;
		}
	argc -= optind;
	argv += optind;
	if (!argc || !mode || mode > 2) {
		printf("Error:: not enough parameter or unspecified mode ...\n\n");
		Usage();
		return 1;
	}
	if (mode == 1) {
		if (argc > 1)
			cnt = strtol(argv[1], NULL, 0);
		rid = strtol(argv[0], NULL, 0);
	} else {
		cnt = argc;
		vs = ait_allocVars(cnt);
		for (i = 0; i < argc; i++)
			AIT_SET_STR(ait_getVars(&vs, i), argv[i]);
	}

	if (cfgLoadConfig(szConfig, &cfg)) {
		printf("Error:: load config #%d - %s\n", cfg_GetErrno(), cfg_GetError());
		return 3;
	} else {
		VERB(1) ShowConfig(mode, rid, cnt);
		if (CheckConfig(mode, rid, cnt)) {
			cfgUnloadConfig(&cfg);
			return 3;
		}
	}

	if (!(key = LoadKey(mode))) {
		cfgUnloadConfig(&cfg);
		return 4;
	}
	if (RSA_size(key) > VOUCHER_MAX_RSA) {
		printf("Error:: RSA key size %d bits. Max %d bits\n", 
				RSA_size(key) * 8, VOUCHER_MAX_RSA * 8);
		RSA_free(key);
		cfgUnloadConfig(&cfg);
		return 5;
	} else
		VERB(1) printf(" + Key size %d bits\n\n", RSA_size(key) * 8);

	if (mode == 1) {
		if (ComputeVouchers(rid, cnt, key)) {
			RSA_free(key);
			cfgUnloadConfig(&cfg);
			return 6;
		}
	} else {
		if (TestVouchers(vs, key)) {
			RSA_free(key);
			cfgUnloadConfig(&cfg);
			return 6;
		}
	}

	RSA_free(key);
	cfgUnloadConfig(&cfg);
	return 0;
}