/*      $OpenBSD: mount_vnd.c,v 1.22 2019/06/28 13:32:45 deraadt Exp $  */
/*
 * Copyright (c) 1993 University of Utah.
 * Copyright (c) 1990, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * the Systems Programming Group of the University of Utah Computer
 * Science Department.
 *
 * 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 University 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 REGENTS 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 <sys/param.h>  /* DEV_BSIZE */
#include <sys/ioctl.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/disklabel.h>

#include <dev/vndioctl.h>

#include <blf.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <readpassphrase.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <limits.h>
#include <util.h>

__dead void      usage(void);
int              config(char *, char *, struct disklabel *, char *, size_t);
char            *get_pkcs_key(char *, char *);

int
main(int argc, char **argv)
{
        int      ch, rv, opt_k = 0, opt_K = 0;
        char    *key = NULL, *mntopts = NULL, *rounds = NULL, *saltopt = NULL;
        size_t   keylen = 0;
        struct disklabel *dp = NULL;

        while ((ch = getopt(argc, argv, "kK:o:S:t:")) != -1) {
                switch (ch) {
                case 'k':
                        opt_k = 1;
                        break;
                case 'K':
                        opt_K = 1;
                        rounds = optarg;
                        break;
                case 'o':
                        mntopts = optarg;
                        break;
                case 'S':
                        saltopt = optarg;
                        break;
                case 't':
                        dp = getdiskbyname(optarg);
                        if (dp == NULL)
                                errx(1, "unknown disk type: %s", optarg);
                        break;
                default:
                        usage();
                        /* NOTREACHED */
                }
        }
        argc -= optind;
        argv += optind;

        if (saltopt && !opt_K)
                errx(1, "-S only makes sense when used with -K");

        if (argc != 2)
                usage();

        if (opt_k || opt_K)
                fprintf(stderr, "WARNING: Consider using softraid crypto.\n");
        if (opt_k) {
                if (opt_K)
                        errx(1, "-k and -K are mutually exclusive");
                key = getpass("Encryption key: ");
                if (key == NULL || (keylen = strlen(key)) == 0)
                        errx(1, "Need an encryption key");
        } else if (opt_K) {
                key = get_pkcs_key(rounds, saltopt);
                keylen = BLF_MAXUTILIZED;
        }
        rv = config(argv[1], argv[0], dp, key, keylen);

        exit(rv);
}

char *
get_pkcs_key(char *arg, char *saltopt)
{
        char             passphrase[128] = {'\0'};
        char             saltbuf[128] = {'\0'}, saltfilebuf[PATH_MAX];
        char            *key = NULL;
        char            *saltfile;
        const char      *errstr;
        int              rounds;

        rounds = strtonum(arg, 1000, INT_MAX, &errstr);
        if (errstr)
                err(1, "rounds: %s", errstr);
        if (readpassphrase("Encryption key: ", passphrase, sizeof(passphrase),
            RPP_REQUIRE_TTY) == NULL)
                errx(1, "Unable to read passphrase");
        if (saltopt)
                saltfile = saltopt;
        else {
                printf("Salt file: ");
                fflush(stdout);
                saltfile = fgets(saltfilebuf, sizeof(saltfilebuf), stdin);
                if (saltfile)
                        saltfile[strcspn(saltfile, "\n")] = '\0';
        }
        if (!saltfile || saltfile[0] == '\0')
                warnx("Skipping salt file, insecure");
        else {
                int fd;

                fd = open(saltfile, O_RDONLY);
                if (fd == -1) {
                        int *s;

                        fprintf(stderr, "Salt file not found, attempting to "
                            "create one\n");
                        fd = open(saltfile, O_RDWR|O_CREAT|O_EXCL, 0600);
                        if (fd == -1)
                                err(1, "Unable to create salt file: '%s'",
                                    saltfile);
                        for (s = (int *)saltbuf;
                            s < (int *)(saltbuf + sizeof(saltbuf)); s++)
                                *s = arc4random();
                        if (write(fd, saltbuf, sizeof(saltbuf))
                            != sizeof(saltbuf))
                                err(1, "Unable to write salt file: '%s'",
                                    saltfile);
                        fprintf(stderr, "Salt file created as '%s'\n",
                            saltfile);
                } else {
                        if (read(fd, saltbuf, sizeof(saltbuf))
                            != sizeof(saltbuf))
                                err(1, "Unable to read salt file: '%s'",
                                    saltfile);
                }
                close(fd);
        }
        if ((key = calloc(1, BLF_MAXUTILIZED)) == NULL)
                err(1, NULL);
        if (pkcs5_pbkdf2(passphrase, sizeof(passphrase), saltbuf,
            sizeof (saltbuf), key, BLF_MAXUTILIZED, rounds))
                errx(1, "pkcs5_pbkdf2 failed");
        explicit_bzero(passphrase, sizeof(passphrase));

        return (key);
}

int
config(char *dev, char *file, struct disklabel *dp, char *key, size_t keylen)
{
        struct vnd_ioctl vndio;
        char *rdev;
        int fd, rv = -1;

        if ((fd = opendev(dev, O_RDONLY, OPENDEV_PART, &rdev)) == -1) {
                err(4, "%s", rdev);
                goto out;
        }

        vndio.vnd_file = file;
        vndio.vnd_secsize = (dp && dp->d_secsize) ? dp->d_secsize : DEV_BSIZE;
        vndio.vnd_nsectors = (dp && dp->d_nsectors) ? dp->d_nsectors : 100;
        vndio.vnd_ntracks = (dp && dp->d_ntracks) ? dp->d_ntracks : 1;
        vndio.vnd_key = (u_char *)key;
        vndio.vnd_keylen = keylen;

        /*
         * Configure the device
         */
        rv = ioctl(fd, VNDIOCSET, &vndio);
        if (rv)
                warn("VNDIOCSET");

        close(fd);
        fflush(stdout);
 out:
        if (key)
                explicit_bzero(key, keylen);
        return (rv < 0);
}

__dead void
usage(void)
{
        (void)fprintf(stderr,
            "usage: mount_vnd [-k] [-K rounds] [-o options] "
            "[-S saltfile] [-t disktype]\n"
            "\t\t image vnd_dev\n");
        exit(1);
}