/*      $OpenBSD: passwd.c,v 1.57 2026/03/11 14:59:10 deraadt Exp $     */

/*
 * Copyright (c) 1987, 1993, 1994, 1995
 *      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/types.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/wait.h>

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

#include "util.h"

static char pw_defdir[] = "/etc";
static char *pw_dir = pw_defdir;
static char *pw_lck;

char *
pw_file(const char *nm)
{
        const char *p = strrchr(nm, '/');
        char *new_nm;

        if (p)
                p++;
        else
                p = nm;

        if (asprintf(&new_nm, "%s/%s", pw_dir, p) == -1)
                return NULL;
        return new_nm;
}

void
pw_setdir(const char *dir)
{
        char *p;

        if (strcmp (dir, pw_dir) == 0)
                return;
        if (pw_dir != pw_defdir)
                free(pw_dir);
        pw_dir = strdup(dir);
        if (pw_lck) {
                p = pw_file(pw_lck);
                free(pw_lck);
                pw_lck = p;
        }
}


int
pw_lock(int retries)
{
        int i, fd;
        mode_t old_mode;

        if (!pw_lck) {
                errno = EINVAL;
                return (-1);
        }
        /* Acquire the lock file.  */
        old_mode = umask(0);
        fd = open(pw_lck, O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0600);
        for (i = 0; i < retries && fd == -1 && errno == EEXIST; i++) {
                sleep(1);
                fd = open(pw_lck, O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0600);
        }
        (void) umask(old_mode);
        return (fd);
}

int
pw_mkdb(char *username, int flags)
{
        int pstat, ac;
        pid_t pid;
        char *av[8];
        struct stat sb;

        if (pw_lck == NULL)
                return(-1);

        /* A zero length passwd file is never ok */
        if (stat(pw_lck, &sb) == 0 && sb.st_size == 0) {
                warnx("%s is zero length", pw_lck);
                return (-1);
        }

        ac = 0;
        av[ac++] = "pwd_mkdb";
        av[ac++] = "-d";
        av[ac++] = pw_dir;
        if (flags & _PASSWORD_SECUREONLY)
                av[ac++] = "-s";
        else if (!(flags & _PASSWORD_OMITV7))
                av[ac++] = "-p";
        if (username) {
                av[ac++] = "-u";
                av[ac++] = username;
        }
        av[ac++] = pw_lck;
        av[ac] = NULL;

        pid = vfork();
        if (pid == -1)
                return (-1);
        if (pid == 0) {
                if (pw_lck)
                        execv(_PATH_PWD_MKDB, av);
                _exit(1);
        }
        pid = waitpid(pid, &pstat, 0);
        if (pid == -1 || !WIFEXITED(pstat) || WEXITSTATUS(pstat) != 0)
                return (-1);
        return (0);
}

int
pw_abort(void)
{
        return (pw_lck ? unlink(pw_lck) : -1);
}

/* Everything below this point is intended for the convenience of programs
 * which allow a user to interactively edit the passwd file.  Errors in the
 * routines below will cause the process to abort. */

static pid_t editpid = -1;

static void
pw_cont(int signo)
{
        int save_errno = errno;

        if (editpid != -1)
                kill(editpid, signo);
        errno = save_errno;
}

void
pw_init(void)
{
        struct rlimit rlim;

        /* Unlimited resource limits. */
        rlim.rlim_cur = rlim.rlim_max = RLIM_INFINITY;
        (void)setrlimit(RLIMIT_CPU, &rlim);
        (void)setrlimit(RLIMIT_FSIZE, &rlim);
        (void)setrlimit(RLIMIT_STACK, &rlim);
        (void)setrlimit(RLIMIT_DATA, &rlim);
        (void)setrlimit(RLIMIT_RSS, &rlim);

        /* Don't drop core (not really necessary, but GP's). */
        rlim.rlim_cur = rlim.rlim_max = 0;
        (void)setrlimit(RLIMIT_CORE, &rlim);

        /* Turn off signals. */
        (void)signal(SIGALRM, SIG_IGN);
        (void)signal(SIGHUP, SIG_IGN);
        (void)signal(SIGINT, SIG_IGN);
        (void)signal(SIGPIPE, SIG_IGN);
        (void)signal(SIGQUIT, SIG_IGN);
        (void)signal(SIGTERM, SIG_IGN);
        (void)signal(SIGCONT, pw_cont);

        if (!pw_lck)
                pw_lck = pw_file(_PATH_MASTERPASSWD_LOCK);
}

void
pw_edit(int notsetuid, const char *filename)
{
        int pstat;
        char *p;
        char *editor;
        char *argp[] = {"sh", "-c", NULL, NULL};

        if (!filename) {
                filename = pw_lck;
                if (!filename)
                        return;
        }

        if ((editor = getenv("EDITOR")) == NULL)
                editor = _PATH_VI;

        if (asprintf(&p, "%s %s", editor, filename) == -1)
                return;
        argp[2] = p;

        switch (editpid = vfork()) {
        case -1:                        /* error */
                free(p);
                return;
        case 0:                         /* child */
                if (notsetuid) {
                        setgid(getgid());
                        setuid(getuid());
                }
                execv(_PATH_BSHELL, argp);
                _exit(127);
        }

        free(p);
        for (;;) {
                editpid = waitpid(editpid, (int *)&pstat, WUNTRACED);
                if (editpid == -1)
                        pw_error(editor, 1, 1);
                else if (WIFSTOPPED(pstat))
                        raise(WSTOPSIG(pstat));
                else if (WIFEXITED(pstat) && WEXITSTATUS(pstat) == 0)
                        break;
                else
                        pw_error(editor, 1, 1);
        }
        editpid = -1;
}

void
pw_prompt(void)
{
        int first, c;

        (void)printf("re-edit the password file? [y]: ");
        (void)fflush(stdout);
        first = c = getchar();
        while (c != '\n' && c != EOF)
                c = getchar();
        switch (first) {
        case EOF:
                putchar('\n');
                /* FALLTHROUGH */
        case 'n':
        case 'N':
                pw_error(NULL, 0, 0);
                break;
        }
}

static int
pw_equal(const struct passwd *pw1, const struct passwd *pw2)
{
        return (strcmp(pw1->pw_name, pw2->pw_name) == 0 &&
            pw1->pw_uid == pw2->pw_uid &&
            pw1->pw_gid == pw2->pw_gid &&
            strcmp(pw1->pw_class, pw2->pw_class) == 0 &&
            pw1->pw_change == pw2->pw_change &&
            pw1->pw_expire == pw2->pw_expire &&
            strcmp(pw1->pw_gecos, pw2->pw_gecos) == 0 &&
            strcmp(pw1->pw_dir, pw2->pw_dir) == 0 &&
            strcmp(pw1->pw_shell, pw2->pw_shell) == 0);
}

static int
pw_write_entry(FILE *to, const struct passwd *pw)
{
        char    gidstr[16], uidstr[16];

        /* Preserve gid/uid -1 */
        if (pw->pw_gid == (gid_t)-1)
                strlcpy(gidstr, "-1", sizeof(gidstr));
        else
                snprintf(gidstr, sizeof(gidstr), "%u", (u_int)pw->pw_gid);

        if (pw->pw_uid == (uid_t)-1)
                strlcpy(uidstr, "-1", sizeof(uidstr));
        else
                snprintf(uidstr, sizeof(uidstr), "%u", (u_int)pw->pw_uid);

        return fprintf(to, "%s:%s:%s:%s:%s:%lld:%lld:%s:%s:%s\n",
            pw->pw_name, pw->pw_passwd, uidstr, gidstr, pw->pw_class,
            (long long)pw->pw_change, (long long)pw->pw_expire,
            pw->pw_gecos, pw->pw_dir, pw->pw_shell);
}

void
pw_copy(int ffd, int tfd, const struct passwd *pw, const struct passwd *opw)
{
        struct passwd tpw;
        FILE   *from, *to;
        int     done;
        char   *p, *ep, buf[8192];
        char   *master = pw_file(_PATH_MASTERPASSWD);

        if (!master)
                pw_error(NULL, 0, 1);
        if (!(from = fdopen(ffd, "re")))
                pw_error(master, 1, 1);
        if (!(to = fdopen(tfd, "we")))
                pw_error(pw_lck ? pw_lck : NULL, pw_lck ? 1 : 0, 1);

        for (done = 0; fgets(buf, (int)sizeof(buf), from);) {
                if ((ep = strchr(buf, '\n')) == NULL) {
                        warnx("%s: line too long", master);
                        pw_error(NULL, 0, 1);
                }
                if (done) {
                        if (fputs(buf, to))
                                goto fail;
                        continue;
                }
                if (!(p = strchr(buf, ':'))) {
                        warnx("%s: corrupted entry", master);
                        pw_error(NULL, 0, 1);
                }
                *p = '\0';
                if (strcmp(buf, opw ? opw->pw_name : pw->pw_name)) {
                        *p = ':';
                        if (fputs(buf, to))
                                goto fail;
                        continue;
                }
                if (opw != NULL) {
                        *p = ':';
                        *ep = '\0';
                        if (!pw_scan(buf, &tpw, NULL))
                                pw_error(NULL, 0, 1);
                        if (!pw_equal(&tpw, opw)) {
                                warnx("%s: inconsistent entry", master);
                                pw_error(NULL, 0, 1);
                        }
                }
                if (pw_write_entry(to, pw) == -1)
                        goto fail;
                done = 1;
        }
        if (!done && pw_write_entry(to, pw) == -1)
                goto fail;

        if (ferror(to) || fflush(to))
fail:
                pw_error(NULL, 0, 1);
        free(master);
        (void)fclose(to);
}

int
pw_scan(char *bp, struct passwd *pw, int *flags)
{
        int root;
        char *p, *sh;
        const char *errstr;

        if (flags != NULL)
                *flags = 0;

        if (!(p = strsep(&bp, ":")) || *p == '\0')      /* login */
                goto fmt;
        pw->pw_name = p;
        root = !strcmp(pw->pw_name, "root");

        if (!(pw->pw_passwd = strsep(&bp, ":")))        /* passwd */
                goto fmt;

        if (!(p = strsep(&bp, ":")))                    /* uid */
                goto fmt;
        pw->pw_uid = strtonum(p, -1, UID_MAX, &errstr);
        if (errstr != NULL) {
                if (*p != '\0') {
                        warnx("uid is %s", errstr);
                        return (0);
                }
                if (flags != NULL)
                        *flags |= _PASSWORD_NOUID;
        }
        if (root && pw->pw_uid) {
                warnx("root uid should be 0");
                return (0);
        }

        if (!(p = strsep(&bp, ":")))                    /* gid */
                goto fmt;
        pw->pw_gid = strtonum(p, -1, GID_MAX, &errstr);
        if (errstr != NULL) {
                if (*p != '\0') {
                        warnx("gid is %s", errstr);
                        return (0);
                }
                if (flags != NULL)
                        *flags |= _PASSWORD_NOGID;
        }

        pw->pw_class = strsep(&bp, ":");                /* class */
        if (!(p = strsep(&bp, ":")))                    /* change */
                goto fmt;
        pw->pw_change = atoll(p);
        if ((*p == '\0') && (flags != (int *)NULL))
                *flags |= _PASSWORD_NOCHG;
        if (!(p = strsep(&bp, ":")))                    /* expire */
                goto fmt;
        pw->pw_expire = atoll(p);
        if ((*p == '\0') && (flags != (int *)NULL))
                *flags |= _PASSWORD_NOEXP;
        pw->pw_gecos = strsep(&bp, ":");                /* gecos */
        pw->pw_dir = strsep(&bp, ":");                  /* directory */
        if (!(pw->pw_shell = strsep(&bp, ":")))         /* shell */
                goto fmt;

        p = pw->pw_shell;
        if (root && *p) {                               /* empty == /bin/sh */
                for (setusershell();;) {
                        if (!(sh = getusershell())) {
                                warnx("warning, unknown root shell");
                                break;
                        }
                        if (!strcmp(p, sh))
                                break;
                }
                endusershell();
        }

        if ((p = strsep(&bp, ":"))) {                   /* too many */
fmt:            warnx("corrupted entry");
                return (0);
        }

        return (1);
}

__dead void
pw_error(const char *name, int error, int eval)
{
        char   *master = pw_file(_PATH_MASTERPASSWD);

        if (error) {
                if (name)
                        warn("%s", name);
                else
                        warn(NULL);
        }
        if (master) {
                warnx("%s: unchanged", master);
                free(master);
        }

        pw_abort();
        exit(eval);
}