FreeBSD-5.3/lib/libutil/pw_util.c
/*-
* Copyright (c) 1990, 1993, 1994
* The Regents of the University of California. All rights reserved.
* Copyright (c) 2002 Networks Associates Technology, Inc.
* All rights reserved.
*
* Portions of this software were developed for the FreeBSD Project by
* ThinkSec AS and NAI Labs, the Security Research Division of Network
* Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035
* ("CBOSS"), as part of the DARPA CHATS research program.
*
* 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 the University of
* California, Berkeley and its contributors.
* 4. 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.
*/
#ifndef lint
#if 0
static const char sccsid[] = "@(#)pw_util.c 8.3 (Berkeley) 4/2/94";
#endif
static const char rcsid[] =
"$FreeBSD: src/lib/libutil/pw_util.c,v 1.35 2004/05/18 15:53:58 stefanf Exp $";
#endif /* not lint */
/*
* This file is used by all the "password" programs; vipw(8), chpass(1),
* and passwd(1).
*/
#include <sys/param.h>
#include <sys/errno.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <ctype.h>
#include <err.h>
#include <fcntl.h>
#include <inttypes.h>
#include <libgen.h>
#include <paths.h>
#include <pwd.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <libutil.h>
static pid_t editpid = -1;
static int lockfd = -1;
static char masterpasswd[PATH_MAX];
static char passwd_dir[PATH_MAX];
static char tempname[PATH_MAX];
static int initialized;
#if 0
void
pw_cont(int sig)
{
if (editpid != -1)
kill(editpid, sig);
}
#endif
/*
* Initialize statics and set limits, signals & umask to try to avoid
* interruptions, crashes etc. that might expose passord data.
*/
int
pw_init(const char *dir, const char *master)
{
#if 0
struct rlimit rlim;
#endif
if (dir == NULL) {
strcpy(passwd_dir, _PATH_ETC);
} else {
if (strlen(dir) >= sizeof(passwd_dir)) {
errno = ENAMETOOLONG;
return (-1);
}
strcpy(passwd_dir, dir);
}
if (master == NULL) {
if (dir == NULL) {
strcpy(masterpasswd, _PATH_MASTERPASSWD);
} else if (snprintf(masterpasswd, sizeof(masterpasswd), "%s/%s",
passwd_dir, _MASTERPASSWD) > (int)sizeof(masterpasswd)) {
errno = ENAMETOOLONG;
return (-1);
}
} else {
if (strlen(master) >= sizeof(masterpasswd)) {
errno = ENAMETOOLONG;
return (-1);
}
strcpy(masterpasswd, master);
}
/*
* The code that follows is extremely disruptive to the calling
* process, and is therefore disabled until someone can conceive
* of a realistic scenario where it would fend off a compromise.
* Race conditions concerning the temporary files can be guarded
* against in other ways than masking signals (by checking stat(2)
* results after creation).
*/
#if 0
/* 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);
/* Create with exact permissions. */
(void)umask(0);
#endif
initialized = 1;
return (0);
}
/*
* Lock the master password file.
*/
int
pw_lock(void)
{
if (*masterpasswd == '\0')
return (-1);
/*
* If the master password file doesn't exist, the system is hosed.
* Might as well try to build one. Set the close-on-exec bit so
* that users can't get at the encrypted passwords while editing.
* Open should allow flock'ing the file; see 4.4BSD. XXX
*/
for (;;) {
struct stat st;
lockfd = open(masterpasswd, O_RDONLY, 0);
if (lockfd < 0 || fcntl(lockfd, F_SETFD, 1) == -1)
err(1, "%s", masterpasswd);
/* XXX vulnerable to race conditions */
if (flock(lockfd, LOCK_EX|LOCK_NB) == -1) {
if (errno == EWOULDBLOCK) {
errx(1, "the password db file is busy");
} else {
err(1, "could not lock the passwd file: ");
}
}
/*
* If the password file was replaced while we were trying to
* get the lock, our hardlink count will be 0 and we have to
* close and retry.
*/
if (fstat(lockfd, &st) == -1)
err(1, "fstat() failed: ");
if (st.st_nlink != 0)
break;
close(lockfd);
lockfd = -1;
}
return (lockfd);
}
/*
* Create and open a presumably safe temp file for editing the password
* data, and copy the master password file into it.
*/
int
pw_tmp(int mfd)
{
char buf[8192];
ssize_t nr;
const char *p;
int tfd;
if (*masterpasswd == '\0')
return (-1);
if ((p = strrchr(masterpasswd, '/')))
++p;
else
p = masterpasswd;
if (snprintf(tempname, sizeof(tempname), "%.*spw.XXXXXX",
(int)(p - masterpasswd), masterpasswd) >= (int)sizeof(tempname)) {
errno = ENAMETOOLONG;
return (-1);
}
if ((tfd = mkstemp(tempname)) == -1)
return (-1);
if (mfd != -1) {
while ((nr = read(mfd, buf, sizeof(buf))) > 0)
if (write(tfd, buf, (size_t)nr) != nr)
break;
if (nr != 0) {
unlink(tempname);
*tempname = '\0';
close(tfd);
return (-1);
}
}
return (tfd);
}
/*
* Regenerate the password database.
*/
int
pw_mkdb(const char *user)
{
int pstat;
pid_t pid;
(void)fflush(stderr);
switch ((pid = fork())) {
case -1:
return (-1);
case 0:
/* child */
if (user == NULL)
execl(_PATH_PWD_MKDB, "pwd_mkdb", "-p",
"-d", passwd_dir, tempname, (char *)NULL);
else
execl(_PATH_PWD_MKDB, "pwd_mkdb", "-p",
"-d", passwd_dir, "-u", user, tempname,
(char *)NULL);
_exit(1);
/* NOTREACHED */
default:
/* parent */
break;
}
if (waitpid(pid, &pstat, 0) == -1)
return (-1);
if (WIFEXITED(pstat) && WEXITSTATUS(pstat) == 0)
return (0);
errno = 0;
return (-1);
}
/*
* Edit the temp file. Return -1 on error, >0 if the file was modified, 0
* if it was not.
*/
int
pw_edit(int notsetuid)
{
struct sigaction sa, sa_int, sa_quit;
sigset_t oldsigset, sigset;
struct stat st1, st2;
const char *editor;
int pstat;
if ((editor = getenv("EDITOR")) == NULL)
editor = _PATH_VI;
if (stat(tempname, &st1) == -1)
return (-1);
sa.sa_handler = SIG_IGN;
sigemptyset(&sa.sa_mask);
sa.sa_flags = 0;
sigaction(SIGINT, &sa, &sa_int);
sigaction(SIGQUIT, &sa, &sa_quit);
sigemptyset(&sigset);
sigaddset(&sigset, SIGCHLD);
sigprocmask(SIG_BLOCK, &sigset, &oldsigset);
switch ((editpid = fork())) {
case -1:
return (-1);
case 0:
sigaction(SIGINT, &sa_int, NULL);
sigaction(SIGQUIT, &sa_quit, NULL);
sigprocmask(SIG_SETMASK, &oldsigset, NULL);
if (notsetuid) {
(void)setgid(getgid());
(void)setuid(getuid());
}
errno = 0;
execlp(editor, basename(editor), tempname, (char *)NULL);
_exit(errno);
default:
/* parent */
break;
}
for (;;) {
if (waitpid(editpid, &pstat, WUNTRACED) == -1) {
if (errno == EINTR)
continue;
unlink(tempname);
editpid = -1;
break;
} else if (WIFSTOPPED(pstat)) {
raise(WSTOPSIG(pstat));
} else if (WIFEXITED(pstat) && WEXITSTATUS(pstat) == 0) {
editpid = -1;
break;
} else {
unlink(tempname);
editpid = -1;
break;
}
}
sigaction(SIGINT, &sa_int, NULL);
sigaction(SIGQUIT, &sa_quit, NULL);
sigprocmask(SIG_SETMASK, &oldsigset, NULL);
if (stat(tempname, &st2) == -1)
return (-1);
return (st1.st_mtime != st2.st_mtime);
}
/*
* Clean up. Preserve errno for the caller's convenience.
*/
void
pw_fini(void)
{
int serrno, status;
if (!initialized)
return;
initialized = 0;
serrno = errno;
if (editpid != -1) {
kill(editpid, SIGTERM);
kill(editpid, SIGCONT);
waitpid(editpid, &status, 0);
editpid = -1;
}
if (*tempname != '\0') {
unlink(tempname);
*tempname = '\0';
}
if (lockfd != -1)
close(lockfd);
errno = serrno;
}
/*
* Compares two struct pwds.
*/
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);
}
/*
* Make a passwd line out of a struct passwd.
*/
char *
pw_make(const struct passwd *pw)
{
char *line;
asprintf(&line, "%s:%s:%ju:%ju:%s:%ju:%ju:%s:%s:%s", pw->pw_name,
pw->pw_passwd, (uintmax_t)pw->pw_uid, (uintmax_t)pw->pw_gid,
pw->pw_class, (uintmax_t)pw->pw_change, (uintmax_t)pw->pw_expire,
pw->pw_gecos, pw->pw_dir, pw->pw_shell);
return line;
}
/*
* Copy password file from one descriptor to another, replacing or adding
* a single record on the way.
*/
int
pw_copy(int ffd, int tfd, const struct passwd *pw, struct passwd *old_pw)
{
char buf[8192], *end, *line, *p, *q, *r, t;
struct passwd *fpw;
size_t len;
int eof, readlen;
if ((line = pw_make(pw)) == NULL)
return (-1);
eof = 0;
len = 0;
p = q = end = buf;
for (;;) {
/* find the end of the current line */
for (p = q; q < end && *q != '\0'; ++q)
if (*q == '\n')
break;
/* if we don't have a complete line, fill up the buffer */
if (q >= end) {
if (eof)
break;
if ((size_t)(q - p) >= sizeof(buf)) {
warnx("passwd line too long");
errno = EINVAL; /* hack */
goto err;
}
if (p < end) {
q = memmove(buf, p, end - p);
end -= p - buf;
} else {
p = q = end = buf;
}
readlen = read(ffd, end, sizeof(buf) - (end - buf));
if (readlen == -1)
goto err;
else
len = (size_t)readlen;
if (len == 0 && p == buf)
break;
end += len;
len = end - buf;
if (len < (ssize_t)sizeof(buf)) {
eof = 1;
if (len > 0 && buf[len - 1] != '\n')
++len, *end++ = '\n';
}
continue;
}
/* is it a blank line or a comment? */
for (r = p; r < q && isspace(*r); ++r)
/* nothing */ ;
if (r == q || *r == '#') {
/* yep */
if (write(tfd, p, q - p + 1) != q - p + 1)
goto err;
++q;
continue;
}
/* is it the one we're looking for? */
t = *q;
*q = '\0';
fpw = pw_scan(r, PWSCAN_MASTER);
*q = t;
if (strcmp(fpw->pw_name, pw->pw_name) != 0) {
/* nope */
free(fpw);
if (write(tfd, p, q - p + 1) != q - p + 1)
goto err;
++q;
continue;
}
if (old_pw && !pw_equal(fpw, old_pw)) {
warnx("entry inconsistent");
free(fpw);
errno = EINVAL; /* hack */
goto err;
}
free(fpw);
/* it is, replace it */
len = strlen(line);
if (write(tfd, line, len) != (int)len)
goto err;
/* we're done, just copy the rest over */
for (;;) {
if (write(tfd, q, end - q) != end - q)
goto err;
q = buf;
readlen = read(ffd, buf, sizeof(buf));
if (readlen == 0)
break;
else
len = (size_t)readlen;
if (readlen == -1)
goto err;
end = buf + len;
}
goto done;
}
/* if we got here, we have a new entry */
len = strlen(line);
if ((size_t)write(tfd, line, len) != len ||
write(tfd, "\n", 1) != 1)
goto err;
done:
free(line);
return (0);
err:
free(line);
return (-1);
}
/*
* Return the current value of tempname.
*/
const char *
pw_tempname(void)
{
return (tempname);
}
/*
* Duplicate a struct passwd.
*/
struct passwd *
pw_dup(const struct passwd *pw)
{
struct passwd *npw;
ssize_t len;
len = sizeof(*npw) +
(pw->pw_name ? strlen(pw->pw_name) + 1 : 0) +
(pw->pw_passwd ? strlen(pw->pw_passwd) + 1 : 0) +
(pw->pw_class ? strlen(pw->pw_class) + 1 : 0) +
(pw->pw_gecos ? strlen(pw->pw_gecos) + 1 : 0) +
(pw->pw_dir ? strlen(pw->pw_dir) + 1 : 0) +
(pw->pw_shell ? strlen(pw->pw_shell) + 1 : 0);
if ((npw = malloc((size_t)len)) == NULL)
return (NULL);
memcpy(npw, pw, sizeof(*npw));
len = sizeof(*npw);
if (pw->pw_name) {
npw->pw_name = ((char *)npw) + len;
len += sprintf(npw->pw_name, "%s", pw->pw_name) + 1;
}
if (pw->pw_passwd) {
npw->pw_passwd = ((char *)npw) + len;
len += sprintf(npw->pw_passwd, "%s", pw->pw_passwd) + 1;
}
if (pw->pw_class) {
npw->pw_class = ((char *)npw) + len;
len += sprintf(npw->pw_class, "%s", pw->pw_class) + 1;
}
if (pw->pw_gecos) {
npw->pw_gecos = ((char *)npw) + len;
len += sprintf(npw->pw_gecos, "%s", pw->pw_gecos) + 1;
}
if (pw->pw_dir) {
npw->pw_dir = ((char *)npw) + len;
len += sprintf(npw->pw_dir, "%s", pw->pw_dir) + 1;
}
if (pw->pw_shell) {
npw->pw_shell = ((char *)npw) + len;
len += sprintf(npw->pw_shell, "%s", pw->pw_shell) + 1;
}
return (npw);
}
#include "pw_scan.h"
/*
* Wrapper around an internal libc function
*/
struct passwd *
pw_scan(const char *line, int flags)
{
struct passwd pw, *ret;
char *bp;
if ((bp = strdup(line)) == NULL)
return (NULL);
if (!__pw_scan(bp, &pw, flags)) {
free(bp);
return (NULL);
}
ret = pw_dup(&pw);
free(bp);
return (ret);
}