/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1991, 1993, 1994
 *      The Regents of the University of California.  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. 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>
#include <sys/endian.h>
#include <sys/stat.h>
#include <arpa/inet.h>

#include <db.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <libgen.h>
#include <limits.h>
#include <pwd.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "pw_scan.h"

#define INSECURE        1
#define SECURE          2
#define PERM_INSECURE   (S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH)
#define PERM_SECURE     (S_IRUSR|S_IWUSR)
#define LEGACY_VERSION(x)  _PW_VERSIONED(x, 3)
#define CURRENT_VERSION(x) _PW_VERSIONED(x, 4)

static HASHINFO openinfo = {
        4096,           /* bsize */
        32,             /* ffactor */
        256,            /* nelem */
        2048 * 1024,    /* cachesize */
        NULL,           /* hash() */
        BIG_ENDIAN      /* lorder */
};

static enum state { FILE_INSECURE, FILE_SECURE, FILE_ORIG } clean;
static struct passwd pwd;                       /* password structure */
static char *pname;                             /* password file name */
static char prefix[MAXPATHLEN];

static int is_comment;  /* flag for comments */
static char line[LINE_MAX];

void    cleanup(void);
void    error(const char *);
void    cp(char *, char *, mode_t mode);
void    mv(char *, char *);
int     scan(FILE *, struct passwd *);
static void     usage(void);

int
main(int argc, char *argv[])
{
        static char verskey[] = _PWD_VERSION_KEY;
        char version = _PWD_CURRENT_VERSION;
        DB *dp, *sdp, *pw_db;
        DBT data, sdata, key;
        FILE *fp, *oldfp;
        sigset_t set;
        int ch, cnt, ypcnt, makeold, tfd, yp_enabled = 0;
        unsigned int len;
        uint32_t store;
        const char *t;
        char *p;
        char buf[MAX(MAXPATHLEN, LINE_MAX * 2)];
        char sbuf[MAX(MAXPATHLEN, LINE_MAX * 2)];
        char buf2[MAXPATHLEN];
        char sbuf2[MAXPATHLEN];
        char tbuf[1024];
        char *username;
        u_int method, methoduid;
        int Cflag, dflag, iflag;
        int nblock = 0;

        iflag = dflag = Cflag = 0;
        strcpy(prefix, _PATH_PWD);
        makeold = 0;
        username = NULL;
        oldfp = NULL;
        while ((ch = getopt(argc, argv, "Cd:iNps:u:v")) != -1)
                switch(ch) {
                case 'C':                       /* verify only */
                        Cflag = 1;
                        break;
                case 'd':
                        dflag++;
                        strlcpy(prefix, optarg, sizeof(prefix));
                        break;
                case 'i':
                        iflag++;
                        break;
                case 'N':                       /* do not wait for lock */
                        nblock = LOCK_NB;       /* will fail if locked */
                        break;
                case 'p':                       /* create V7 "file.orig" */
                        makeold = 1;
                        break;
                case 's':                       /* change default cachesize */
                        openinfo.cachesize = atoi(optarg) * 1024 * 1024;
                        break;
                case 'u':                       /* only update this record */
                        username = optarg;
                        break;
                case 'v':                       /* backward compatible */
                        break;
                default:
                        usage();
                }
        argc -= optind;
        argv += optind;

        if (argc != 1 || (username && (*username == '+' || *username == '-')))
                usage();

        /*
         * This could be changed to allow the user to interrupt.
         * Probably not worth the effort.
         */
        sigemptyset(&set);
        sigaddset(&set, SIGTSTP);
        sigaddset(&set, SIGHUP);
        sigaddset(&set, SIGINT);
        sigaddset(&set, SIGQUIT);
        sigaddset(&set, SIGTERM);
        (void)sigprocmask(SIG_BLOCK, &set, (sigset_t *)NULL);

        /* We don't care what the user wants. */
        (void)umask(0);

        pname = *argv;

        /*
         * Open and lock the original password file.  We have to check
         * the hardlink count after we get the lock to handle any potential
         * unlink/rename race.
         *
         * This lock is necessary when someone runs pwd_mkdb manually, directly
         * on master.passwd, to handle the case where a user might try to
         * change his password while pwd_mkdb is running. 
         */
        for (;;) {
                struct stat st;

                if (!(fp = fopen(pname, "r")))
                        error(pname);
                if (flock(fileno(fp), LOCK_EX|nblock) < 0 && !(dflag && iflag))
                        error("flock");
                if (fstat(fileno(fp), &st) < 0)
                        error(pname);
                if (st.st_nlink != 0)
                        break;
                fclose(fp);
                fp = NULL;
        }

        /* check only if password database is valid */
        if (Cflag) {
                while (scan(fp, &pwd))
                        if (!is_comment && strlen(pwd.pw_name) >= MAXLOGNAME) {
                                warnx("%s: username too long", pwd.pw_name);
                                exit(1);
                        }
                exit(0);
        }

        /* Open the temporary insecure password database. */
        (void)snprintf(buf, sizeof(buf), "%s/%s.tmp", prefix, _MP_DB);
        (void)snprintf(sbuf, sizeof(sbuf), "%s/%s.tmp", prefix, _SMP_DB);
        if (username) {
                int use_version;

                (void)snprintf(buf2, sizeof(buf2), "%s/%s", prefix, _MP_DB);
                (void)snprintf(sbuf2, sizeof(sbuf2), "%s/%s", prefix, _SMP_DB);

                clean = FILE_INSECURE;
                cp(buf2, buf, PERM_INSECURE);
                dp = dbopen(buf,
                    O_RDWR|O_EXCL, PERM_INSECURE, DB_HASH, &openinfo);
                if (dp == NULL)
                        error(buf);

                clean = FILE_SECURE;
                cp(sbuf2, sbuf, PERM_SECURE);
                sdp = dbopen(sbuf,
                    O_RDWR|O_EXCL, PERM_SECURE, DB_HASH, &openinfo);
                if (sdp == NULL)
                        error(sbuf);

                /*
                 * Do some trouble to check if we should store this users 
                 * uid. Don't use getpwnam/getpwuid as that interferes 
                 * with NIS.
                 */
                pw_db = dbopen(_PATH_MP_DB, O_RDONLY, 0, DB_HASH, NULL);
                if (!pw_db)
                        error(_MP_DB);

                key.data = verskey;
                key.size = sizeof(verskey)-1;
                if ((pw_db->get)(pw_db, &key, &data, 0) == 0)
                        use_version = *(unsigned char *)data.data;
                else
                        use_version = 3;
                buf[0] = _PW_VERSIONED(_PW_KEYBYNAME, use_version);
                len = strlen(username);

                /* Only check that username fits in buffer */
                memmove(buf + 1, username, MIN(len, sizeof(buf) - 1));
                key.data = (u_char *)buf;
                key.size = len + 1;
                if ((pw_db->get)(pw_db, &key, &data, 0) == 0) {
                        p = (char *)data.data;

                        /* jump over pw_name and pw_passwd, to get to pw_uid */
                        while (*p++)
                                ;
                        while (*p++)
                                ;

                        buf[0] = _PW_VERSIONED(_PW_KEYBYUID, use_version);
                        memmove(buf + 1, p, sizeof(store));
                        key.data = (u_char *)buf;
                        key.size = sizeof(store) + 1;

                        if ((pw_db->get)(pw_db, &key, &data, 0) == 0) {
                                /* First field of data.data holds pw_pwname */
                                if (!strcmp(data.data, username))
                                        methoduid = 0;
                                else
                                        methoduid = R_NOOVERWRITE;
                        } else {
                                methoduid = R_NOOVERWRITE;
                        }
                } else {
                        methoduid = R_NOOVERWRITE;
                }
                if ((pw_db->close)(pw_db))
                        error("close pw_db");
                method = 0;
        } else {
                dp = dbopen(buf,
                    O_RDWR|O_CREAT|O_EXCL, PERM_INSECURE, DB_HASH, &openinfo);
                if (dp == NULL)
                        error(buf);
                clean = FILE_INSECURE;

                sdp = dbopen(sbuf,
                    O_RDWR|O_CREAT|O_EXCL, PERM_SECURE, DB_HASH, &openinfo);
                if (sdp == NULL)
                        error(sbuf);
                clean = FILE_SECURE;

                method = R_NOOVERWRITE;
                methoduid = R_NOOVERWRITE;
        }

        /*
         * Open file for old password file.  Minor trickiness -- don't want to
         * chance the file already existing, since someone (stupidly) might
         * still be using this for permission checking.  So, open it first and
         * fdopen the resulting fd.  The resulting file should be readable by
         * everyone.
         */
        if (makeold) {
                (void)snprintf(buf, sizeof(buf), "%s.orig", pname);
                if ((tfd = open(buf,
                    O_WRONLY|O_CREAT|O_EXCL, PERM_INSECURE)) < 0)
                        error(buf);
                if ((oldfp = fdopen(tfd, "w")) == NULL)
                        error(buf);
                clean = FILE_ORIG;
        }

        /*
         * The databases actually contain three copies of the original data.
         * Each password file entry is converted into a rough approximation
         * of a ``struct passwd'', with the strings placed inline.  This
         * object is then stored as the data for three separate keys.  The
         * first key * is the pw_name field prepended by the _PW_KEYBYNAME
         * character.  The second key is the pw_uid field prepended by the
         * _PW_KEYBYUID character.  The third key is the line number in the
         * original file prepended by the _PW_KEYBYNUM character.  (The special
         * characters are prepended to ensure that the keys do not collide.)
         */
        /* In order to transition this file into a machine-independent
         * form, we have to change the format of entries.  However, since
         * older binaries will still expect the old MD format entries, we 
         * create those as usual and use versioned tags for the new entries.
         */
        if (username == NULL) {
                /* Do not add the VERSION tag when updating a single
                 * user.  When operating on `old format' databases, this
                 * would result in applications `seeing' only the updated
                 * entries.
                 */
                key.data = verskey;
                key.size = sizeof(verskey)-1;
                data.data = &version;
                data.size = 1;
                if ((dp->put)(dp, &key, &data, 0) == -1)
                        error("put");
                if ((sdp->put)(sdp, &key, &data, 0) == -1)
                        error("put");
        }
        ypcnt = 0;
        data.data = (u_char *)buf;
        sdata.data = (u_char *)sbuf;
        key.data = (u_char *)tbuf;
        for (cnt = 1; scan(fp, &pwd); ++cnt) {
                if (!is_comment && 
                    (pwd.pw_name[0] == '+' || pwd.pw_name[0] == '-')) {
                        yp_enabled = 1;
                        ypcnt++;
                }
                if (is_comment)
                        --cnt;
#define COMPACT(e)      t = e; while ((*p++ = *t++));
#define SCALAR(e)       store = htonl((uint32_t)(e));      \
                        memmove(p, &store, sizeof(store)); \
                        p += sizeof(store);
#define LSCALAR(e)      store = HTOL((uint32_t)(e));       \
                        memmove(p, &store, sizeof(store)); \
                        p += sizeof(store);
#define HTOL(e)         (openinfo.lorder == BYTE_ORDER ? \
                        (uint32_t)(e) : \
                        bswap32((uint32_t)(e)))
                if (!is_comment && 
                    (!username || (strcmp(username, pwd.pw_name) == 0))) {
                        /* Create insecure data. */
                        p = buf;
                        COMPACT(pwd.pw_name);
                        COMPACT("*");
                        SCALAR(pwd.pw_uid);
                        SCALAR(pwd.pw_gid);
                        SCALAR(pwd.pw_change);
                        COMPACT(pwd.pw_class);
                        COMPACT(pwd.pw_gecos);
                        COMPACT(pwd.pw_dir);
                        COMPACT(pwd.pw_shell);
                        SCALAR(pwd.pw_expire);
                        SCALAR(pwd.pw_fields);
                        data.size = p - buf;

                        /* Create secure data. */
                        p = sbuf;
                        COMPACT(pwd.pw_name);
                        COMPACT(pwd.pw_passwd);
                        SCALAR(pwd.pw_uid);
                        SCALAR(pwd.pw_gid);
                        SCALAR(pwd.pw_change);
                        COMPACT(pwd.pw_class);
                        COMPACT(pwd.pw_gecos);
                        COMPACT(pwd.pw_dir);
                        COMPACT(pwd.pw_shell);
                        SCALAR(pwd.pw_expire);
                        SCALAR(pwd.pw_fields);
                        sdata.size = p - sbuf;

                        /* Store insecure by name. */
                        tbuf[0] = CURRENT_VERSION(_PW_KEYBYNAME);
                        len = strlen(pwd.pw_name);
                        memmove(tbuf + 1, pwd.pw_name, len);
                        key.size = len + 1;
                        if ((dp->put)(dp, &key, &data, method) == -1)
                                error("put");

                        /* Store insecure by number. */
                        tbuf[0] = CURRENT_VERSION(_PW_KEYBYNUM);
                        store = htonl(cnt);
                        memmove(tbuf + 1, &store, sizeof(store));
                        key.size = sizeof(store) + 1;
                        if ((dp->put)(dp, &key, &data, method) == -1)
                                error("put");

                        /* Store insecure by uid. */
                        tbuf[0] = CURRENT_VERSION(_PW_KEYBYUID);
                        store = htonl(pwd.pw_uid);
                        memmove(tbuf + 1, &store, sizeof(store));
                        key.size = sizeof(store) + 1;
                        if ((dp->put)(dp, &key, &data, methoduid) == -1)
                                error("put");

                        /* Store secure by name. */
                        tbuf[0] = CURRENT_VERSION(_PW_KEYBYNAME);
                        len = strlen(pwd.pw_name);
                        memmove(tbuf + 1, pwd.pw_name, len);
                        key.size = len + 1;
                        if ((sdp->put)(sdp, &key, &sdata, method) == -1)
                                error("put");

                        /* Store secure by number. */
                        tbuf[0] = CURRENT_VERSION(_PW_KEYBYNUM);
                        store = htonl(cnt);
                        memmove(tbuf + 1, &store, sizeof(store));
                        key.size = sizeof(store) + 1;
                        if ((sdp->put)(sdp, &key, &sdata, method) == -1)
                                error("put");

                        /* Store secure by uid. */
                        tbuf[0] = CURRENT_VERSION(_PW_KEYBYUID);
                        store = htonl(pwd.pw_uid);
                        memmove(tbuf + 1, &store, sizeof(store));
                        key.size = sizeof(store) + 1;
                        if ((sdp->put)(sdp, &key, &sdata, methoduid) == -1)
                                error("put");

                        /* Store insecure and secure special plus and special minus */
                        if (pwd.pw_name[0] == '+' || pwd.pw_name[0] == '-') {
                                tbuf[0] = CURRENT_VERSION(_PW_KEYYPBYNUM);
                                store = htonl(ypcnt);
                                memmove(tbuf + 1, &store, sizeof(store));
                                key.size = sizeof(store) + 1;
                                if ((dp->put)(dp, &key, &data, method) == -1)
                                        error("put");
                                if ((sdp->put)(sdp, &key, &sdata, method) == -1)
                                        error("put");
                        }
                }
                /*
                 * Create original style password file entry.
                 *
                 * Don't copy comments since this could reveal encrypted
                 * passwords if entries have been simply commented out
                 * in master.passwd.
                 */
                if (makeold && !is_comment) {
                        char uidstr[20];
                        char gidstr[20];

                        snprintf(uidstr, sizeof(uidstr), "%u", pwd.pw_uid);
                        snprintf(gidstr, sizeof(gidstr), "%u", pwd.pw_gid);

                        if (fprintf(oldfp, "%s:*:%s:%s:%s:%s:%s\n",
                            pwd.pw_name, pwd.pw_fields & _PWF_UID ? uidstr : "",
                            pwd.pw_fields & _PWF_GID ? gidstr : "",
                            pwd.pw_gecos, pwd.pw_dir, pwd.pw_shell) < 0)
                                error("write old");
                }
        }
        /* If YP enabled, set flag. */
        if (yp_enabled) {
                buf[0] = yp_enabled + 2;
                data.size = 1;
                key.size = 1;
                tbuf[0] = CURRENT_VERSION(_PW_KEYYPENABLED);
                if ((dp->put)(dp, &key, &data, method) == -1)
                        error("put");
                if ((sdp->put)(sdp, &key, &data, method) == -1)
                        error("put");
        }

        if ((dp->close)(dp) == -1)
                error("close");
        if ((sdp->close)(sdp) == -1)
                error("close");
        if (makeold) {
                (void)fflush(oldfp);
                if (fclose(oldfp) == EOF)
                        error("close old");
        }

        /* Set master.passwd permissions, in case caller forgot. */
        (void)fchmod(fileno(fp), S_IRUSR|S_IWUSR);

        /* Install as the real password files. */
        (void)snprintf(buf, sizeof(buf), "%s/%s.tmp", prefix, _MP_DB);
        (void)snprintf(buf2, sizeof(buf2), "%s/%s", prefix, _MP_DB);
        mv(buf, buf2);
        (void)snprintf(buf, sizeof(buf), "%s/%s.tmp", prefix, _SMP_DB);
        (void)snprintf(buf2, sizeof(buf2), "%s/%s", prefix, _SMP_DB);
        mv(buf, buf2);
        if (makeold) {
                (void)snprintf(buf2, sizeof(buf2), "%s/%s", prefix, _PASSWD);
                (void)snprintf(buf, sizeof(buf), "%s.orig", pname);
                mv(buf, buf2);
        }
        /*
         * Move the master password LAST -- chpass(1), passwd(1) and vipw(8)
         * all use flock(2) on it to block other incarnations of themselves.
         * The rename means that everything is unlocked, as the original file
         * can no longer be accessed.
         */
        (void)snprintf(buf, sizeof(buf), "%s/%s", prefix, _MASTERPASSWD);
        mv(pname, buf);

        /*
         * Close locked password file after rename()
         */
        if (fclose(fp) == EOF)
                error("close fp");

        exit(0);
}

int
scan(FILE *fp, struct passwd *pw)
{
        static int lcnt;
        size_t len;
        char *p;

        p = fgetln(fp, &len);
        if (p == NULL)
                return (0);
        ++lcnt;
        /*
         * ``... if I swallow anything evil, put your fingers down my
         * throat...''
         *      -- The Who
         */
        if (len > 0 && p[len - 1] == '\n')
                len--;
        if (len >= sizeof(line) - 1) {
                warnx("line #%d too long", lcnt);
                goto fmt;
        }
        memcpy(line, p, len);
        line[len] = '\0';

        /* 
         * Ignore comments: ^[ \t]*#
         */
        for (p = line; *p != '\0'; p++)
                if (*p != ' ' && *p != '\t')
                        break;
        if (*p == '#' || *p == '\0') {
                is_comment = 1;
                return(1);
        } else
                is_comment = 0;

        if (!__pw_scan(line, pw, _PWSCAN_WARN|_PWSCAN_MASTER)) {
                warnx("at line #%d", lcnt);
fmt:            errno = EFTYPE; /* XXX */
                error(pname);
        }

        return (1);
}

void                    
cp(char *from, char *to, mode_t mode)              
{               
        static char buf[MAXBSIZE];
        int from_fd, rcount, to_fd, wcount;

        if ((from_fd = open(from, O_RDONLY, 0)) < 0)
                error(from);
        if ((to_fd = open(to, O_WRONLY|O_CREAT|O_EXCL, mode)) < 0)
                error(to);
        while ((rcount = read(from_fd, buf, MAXBSIZE)) > 0) {
                wcount = write(to_fd, buf, rcount);
                if (rcount != wcount || wcount == -1) {
                        int sverrno = errno;

                        (void)snprintf(buf, sizeof(buf), "%s to %s", from, to);
                        errno = sverrno;
                        error(buf);
                }
        }
        if (rcount < 0) {
                int sverrno = errno;

                (void)snprintf(buf, sizeof(buf), "%s to %s", from, to);
                errno = sverrno;
                error(buf);
        }
}


void
mv(char *from, char *to)
{
        char buf[MAXPATHLEN];
        char *to_dir;
        int to_dir_fd = -1;

        /*
         * Make sure file is safe on disk. To improve performance we will call
         * fsync() to the directory where file lies
         */
        if (rename(from, to) != 0 ||
            (to_dir = dirname(to)) == NULL ||
            (to_dir_fd = open(to_dir, O_RDONLY|O_DIRECTORY)) == -1 ||
            fsync(to_dir_fd) != 0) {
                int sverrno = errno;
                (void)snprintf(buf, sizeof(buf), "%s to %s", from, to);
                errno = sverrno;
                if (to_dir_fd != -1)
                        close(to_dir_fd);
                error(buf);
        }

        if (to_dir_fd != -1)
                close(to_dir_fd);
}

void
error(const char *name)
{

        warn("%s", name);
        cleanup();
        exit(1);
}

void
cleanup(void)
{
        char buf[MAXPATHLEN];

        switch(clean) {
        case FILE_ORIG:
                (void)snprintf(buf, sizeof(buf), "%s.orig", pname);
                (void)unlink(buf);
                /* FALLTHROUGH */
        case FILE_SECURE:
                (void)snprintf(buf, sizeof(buf), "%s/%s.tmp", prefix, _SMP_DB);
                (void)unlink(buf);
                /* FALLTHROUGH */
        case FILE_INSECURE:
                (void)snprintf(buf, sizeof(buf), "%s/%s.tmp", prefix, _MP_DB);
                (void)unlink(buf);
        }
}

static void
usage(void)
{

        (void)fprintf(stderr,
"usage: pwd_mkdb [-CiNp] [-d directory] [-s cachesize] [-u username] file\n");
        exit(1);
}