/* $OpenBSD: cryptutil.c,v 1.10 2015/07/23 22:19:03 tedu Exp $ */
/*
 * Copyright (c) 2014 Ted Unangst <tedu@openbsd.org>
 *
 * 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 THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR 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.
 */
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <pwd.h>
#include <login_cap.h>
#include <errno.h>

int bcrypt_autorounds(void);

int
crypt_checkpass(const char *pass, const char *goodhash)
{
	char dummy[_PASSWORD_LEN];

	if (goodhash == NULL) {
		/* fake it */
		goto fake;
	}

	/* empty password */
	if (strlen(goodhash) == 0 && strlen(pass) == 0)
		return 0;

	if (goodhash[0] == '$' && goodhash[1] == '2') {
		if (bcrypt_checkpass(pass, goodhash))
			goto fail;
		return 0;
	}

	/* unsupported. fake it. */
fake:
	bcrypt_newhash(pass, 8, dummy, sizeof(dummy));
fail:
	errno = EACCES;
	return -1;
}

int
crypt_newhash(const char *pass, const char *pref, char *hash, size_t hashlen)
{
	int rv = -1;
	const char *defaultpref = "blowfish,8";
	const char *errstr;
	const char *choices[] = { "blowfish", "bcrypt" };
	size_t maxchoice = sizeof(choices) / sizeof(choices[0]);
	int i;
	int rounds;

	if (pref == NULL)
		pref = defaultpref;

	for (i = 0; i < maxchoice; i++) {
		const char *choice = choices[i];
		size_t len = strlen(choice);
		if (strcmp(pref, choice) == 0) {
			rounds = bcrypt_autorounds();
			break;
		} else if (strncmp(pref, choice, len) == 0 &&
		    pref[len] == ',') {
			if (strcmp(pref + len + 1, "a") == 0) {
				rounds = bcrypt_autorounds();
			} else {
				rounds = strtonum(pref + len + 1, 4, 31, &errstr);
				if (errstr) {
					errno = EINVAL;
					goto err;
				}
			}
			break;
		}
	}
	if (i == maxchoice) {
		errno = EINVAL;
		goto err;
	}

	rv = bcrypt_newhash(pass, rounds, hash, hashlen);

err:
	return rv;
}