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NetBSD/lib/libutil/passwd.c

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/* $NetBSD: passwd.c,v 1.53 2018/06/24 01:53:14 kamil 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/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: passwd.c,v 1.53 2018/06/24 01:53:14 kamil Exp $");
#endif /* LIBC_SCCS and not lint */
#include <sys/types.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/wait.h>
#include <assert.h>
#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <paths.h>
#include <pwd.h>
#include <grp.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <util.h>
static const char *pw_filename(const char *filename);
static void pw_cont(int sig);
static const char * pw_equal(char *buf, struct passwd *old_pw);
static const char *pw_default(const char *option);
static int read_line(FILE *fp, char *line, int max);
static void trim_whitespace(char *line);
static char pw_prefix[MAXPATHLEN];
const char *
pw_getprefix(void)
{
return(pw_prefix);
}
int
pw_setprefix(const char *new_prefix)
{
size_t length;
_DIAGASSERT(new_prefix != NULL);
length = strlen(new_prefix);
if (length < sizeof(pw_prefix)) {
(void)strcpy(pw_prefix, new_prefix);
while (length > 0 && pw_prefix[length - 1] == '/')
pw_prefix[--length] = '\0';
return(0);
}
errno = ENAMETOOLONG;
return(-1);
}
static const char *
pw_filename(const char *filename)
{
static char newfilename[MAXPATHLEN];
_DIAGASSERT(filename != NULL);
if (pw_prefix[0] == '\0')
return filename;
if (strlen(pw_prefix) + strlen(filename) < sizeof(newfilename))
return strcat(strcpy(newfilename, pw_prefix), filename);
errno = ENAMETOOLONG;
return(NULL);
}
int
pw_lock(int retries)
{
const char *filename;
int i, fd;
mode_t old_mode;
int oerrno;
/* Acquire the lock file. */
filename = pw_filename(_PATH_MASTERPASSWD_LOCK);
if (filename == NULL)
return(-1);
old_mode = umask(0);
fd = open(filename, O_WRONLY|O_CREAT|O_EXCL, 0600);
for (i = 0; i < retries && fd < 0 && errno == EEXIST; i++) {
sleep(1);
fd = open(filename, O_WRONLY|O_CREAT|O_EXCL,
0600);
}
oerrno = errno;
(void)umask(old_mode);
errno = oerrno;
return(fd);
}
int
pw_mkdb(const char *username, int secureonly)
{
const char *args[9];
int pstat, i;
pid_t pid;
pid = vfork();
if (pid == -1)
return -1;
if (pid == 0) {
args[0] = "pwd_mkdb";
args[1] = "-d";
args[2] = pw_prefix;
args[3] = "-pl";
i = 4;
if (secureonly)
args[i++] = "-s";
if (username != NULL) {
args[i++] = "-u";
args[i++] = username;
}
args[i++] = pw_filename(_PATH_MASTERPASSWD_LOCK);
args[i] = NULL;
execv(_PATH_PWD_MKDB, (char * const *)__UNCONST(args));
_exit(1);
}
pid = waitpid(pid, &pstat, 0);
if (pid == -1) {
warn("error waiting for pid %lu", (unsigned long)pid);
return -1;
}
if (WIFEXITED(pstat)) {
if (WEXITSTATUS(pstat) != 0) {
warnx("pwd_mkdb exited with status %d",
WEXITSTATUS(pstat));
return -1;
}
} else if (WIFSIGNALED(pstat)) {
warnx("pwd_mkdb exited with signal %d", WTERMSIG(pstat));
return -1;
}
return 0;
}
int
pw_abort(void)
{
const char *filename;
filename = pw_filename(_PATH_MASTERPASSWD_LOCK);
return((filename == NULL) ? -1 : unlink(filename));
}
/* 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 sig)
{
if (editpid != -1)
kill(editpid, sig);
}
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);
}
void
pw_edit(int notsetuid, const char *filename)
{
int pstat;
char *p;
const char * volatile editor;
const char *argp[] = { "sh", "-c", NULL, NULL };
if (filename == NULL)
filename = _PATH_MASTERPASSWD_LOCK;
filename = pw_filename(filename);
if (filename == NULL)
return;
if ((editor = getenv("EDITOR")) == NULL)
editor = _PATH_VI;
p = malloc(strlen(editor) + 1 + strlen(filename) + 1);
if (p == NULL)
return;
sprintf(p, "%s %s", editor, filename);
argp[2] = p;
switch(editpid = vfork()) {
case -1:
free(p);
return;
case 0:
if (notsetuid) {
setgid(getgid());
setuid(getuid());
}
execvp(_PATH_BSHELL, (char *const *)__UNCONST(argp));
_exit(1);
}
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 c;
(void)printf("re-edit the password file? [y]: ");
(void)fflush(stdout);
c = getchar();
if (c != EOF && c != '\n')
while (getchar() != '\n');
if (c == 'n')
pw_error(NULL, 0, 0);
}
/* for use in pw_copy(). Compare a pw entry to a pw struct. */
/* returns a character string labelling the miscompared field or 0 */
static const char *
pw_equal(char *buf, struct passwd *pw)
{
struct passwd buf_pw;
size_t len;
_DIAGASSERT(buf != NULL);
_DIAGASSERT(pw != NULL);
len = strlen (buf);
if (buf[len-1] == '\n')
buf[len-1] = '\0';
if (!pw_scan(buf, &buf_pw, NULL))
return "corrupt line";
if (strcmp(pw->pw_name, buf_pw.pw_name) != 0)
return "name";
if (pw->pw_uid != buf_pw.pw_uid)
return "uid";
if (pw->pw_gid != buf_pw.pw_gid)
return "gid";
if (strcmp( pw->pw_class, buf_pw.pw_class) != 0)
return "class";
if (pw->pw_change != buf_pw.pw_change)
return "change";
if (pw->pw_expire != buf_pw.pw_expire)
return "expire";
if (strcmp( pw->pw_gecos, buf_pw.pw_gecos) != 0)
return "gecos";
if (strcmp( pw->pw_dir, buf_pw.pw_dir) != 0)
return "dir";
if (strcmp( pw->pw_shell, buf_pw.pw_shell) != 0)
return "shell";
return (char *)0;
}
void
pw_copy(int ffd, int tfd, struct passwd *pw, struct passwd *old_pw)
{
char errbuf[200];
int rv;
rv = pw_copyx(ffd, tfd, pw, old_pw, errbuf, sizeof(errbuf));
if (rv == 0) {
warnx("%s", errbuf);
pw_error(NULL, 0, 1);
}
}
static void
pw_print(FILE *to, const struct passwd *pw)
{
(void)fprintf(to, "%s:%s:%d:%d:%s:%lld:%lld:%s:%s:%s\n",
pw->pw_name, pw->pw_passwd, pw->pw_uid, pw->pw_gid,
pw->pw_class, (long long)pw->pw_change,
(long long)pw->pw_expire,
pw->pw_gecos, pw->pw_dir, pw->pw_shell);
}
int
pw_copyx(int ffd, int tfd, struct passwd *pw, struct passwd *old_pw,
char *errbuf, size_t errbufsz)
{
const char *filename;
char mpwd[MAXPATHLEN], mpwdl[MAXPATHLEN], *p, buf[8192];
FILE *from, *to;
int done;
_DIAGASSERT(pw != NULL);
_DIAGASSERT(errbuf != NULL);
/* old_pw may be NULL */
if ((filename = pw_filename(_PATH_MASTERPASSWD)) == NULL) {
snprintf(errbuf, errbufsz, "%s: %s", pw_prefix,
strerror(errno));
return (0);
}
(void)strcpy(mpwd, filename);
if ((filename = pw_filename(_PATH_MASTERPASSWD_LOCK)) == NULL) {
snprintf(errbuf, errbufsz, "%s: %s", pw_prefix,
strerror(errno));
return (0);
}
(void)strcpy(mpwdl, filename);
if (!(from = fdopen(ffd, "r"))) {
snprintf(errbuf, errbufsz, "%s: %s", mpwd, strerror(errno));
return (0);
}
if (!(to = fdopen(tfd, "w"))) {
snprintf(errbuf, errbufsz, "%s: %s", mpwdl, strerror(errno));
(void)fclose(from);
return (0);
}
for (done = 0; fgets(buf, (int)sizeof(buf), from);) {
const char *neq;
if (!strchr(buf, '\n')) {
snprintf(errbuf, errbufsz, "%s: line too long", mpwd);
(void)fclose(from);
(void)fclose(to);
return (0);
}
if (done) {
(void)fprintf(to, "%s", buf);
if (ferror(to)) {
snprintf(errbuf, errbufsz, "%s",
strerror(errno));
(void)fclose(from);
(void)fclose(to);
return (0);
}
continue;
}
if (!(p = strchr(buf, ':'))) {
snprintf(errbuf, errbufsz, "%s: corrupted entry", mpwd);
(void)fclose(from);
(void)fclose(to);
return (0);
}
*p = '\0';
if (strcmp(buf, pw->pw_name)) {
*p = ':';
(void)fprintf(to, "%s", buf);
if (ferror(to)) {
snprintf(errbuf, errbufsz, "%s",
strerror(errno));
(void)fclose(from);
(void)fclose(to);
return (0);
}
continue;
}
*p = ':';
if (old_pw && (neq = pw_equal(buf, old_pw)) != NULL) {
if (strcmp(neq, "corrupt line") == 0)
(void)snprintf(errbuf, errbufsz,
"%s: entry %s corrupted", mpwd,
pw->pw_name);
else
(void)snprintf(errbuf, errbufsz,
"%s: entry %s inconsistent %s",
mpwd, pw->pw_name, neq);
(void)fclose(from);
(void)fclose(to);
return (0);
}
pw_print(to, pw);
done = 1;
if (ferror(to)) {
snprintf(errbuf, errbufsz, "%s", strerror(errno));
(void)fclose(from);
(void)fclose(to);
return (0);
}
}
/* Only append a new entry if real uid is root! */
if (!done) {
if (getuid() == 0) {
pw_print(to, pw);
done = 1;
} else {
snprintf(errbuf, errbufsz,
"%s: changes not made, no such entry", mpwd);
}
}
if (ferror(to)) {
snprintf(errbuf, errbufsz, "%s", strerror(errno));
(void)fclose(from);
(void)fclose(to);
return (0);
}
(void)fclose(from);
(void)fclose(to);
return (done);
}
void
pw_error(const char *name, int error, int eval)
{
if (error) {
if (name)
warn("%s", name);
else
warn(NULL);
}
warnx("%s%s: unchanged", pw_prefix, _PATH_MASTERPASSWD);
pw_abort();
exit(eval);
}
/* Removes head and/or tail spaces. */
static void
trim_whitespace(char *line)
{
char *p;
_DIAGASSERT(line != NULL);
/* Handle empty string */
if (*line == '\0')
return;
/* Remove leading spaces */
p = line;
while (isspace((unsigned char) *p))
p++;
memmove(line, p, strlen(p) + 1);
/* Handle empty string after removal of whitespace characters */
if (*line == '\0')
return;
/* Remove trailing spaces, line must not be empty string here */
p = line + strlen(line) - 1;
while (isspace((unsigned char) *p))
p--;
*(p + 1) = '\0';
}
/* Get one line, remove spaces from front and tail */
static int
read_line(FILE *fp, char *line, int max)
{
char *p;
_DIAGASSERT(fp != NULL);
_DIAGASSERT(line != NULL);
/* Read one line of config */
if (fgets(line, max, fp) == NULL)
return (0);
if ((p = strchr(line, '\n')) == NULL) {
warnx("line too long");
return (0);
}
*p = '\0';
/* Remove comments */
if ((p = strchr(line, '#')) != NULL)
*p = '\0';
trim_whitespace(line);
return (1);
}
static const char *
pw_default(const char *option)
{
static const char *options[][2] = {
{ "localcipher", "old" },
{ "ypcipher", "old" },
};
size_t i;
_DIAGASSERT(option != NULL);
for (i = 0; i < sizeof(options) / sizeof(options[0]); i++)
if (strcmp(options[i][0], option) == 0)
return (options[i][1]);
return (NULL);
}
/*
* Retrieve password information from the /etc/passwd.conf file, at the
* moment this is only for choosing the cipher to use. It could easily be
* used for other authentication methods as well.
*/
void
pw_getconf(char *data, size_t max, const char *key, const char *option)
{
FILE *fp;
char line[LINE_MAX], *p, *p2;
static char result[LINE_MAX];
int got, found;
const char *cp;
_DIAGASSERT(data != NULL);
_DIAGASSERT(key != NULL);
_DIAGASSERT(option != NULL);
got = 0;
found = 0;
result[0] = '\0';
if ((fp = fopen(_PATH_PASSWD_CONF, "r")) == NULL) {
if ((cp = pw_default(option)) != NULL)
strlcpy(data, cp, max);
else
data[0] = '\0';
return;
}
while (!found && (got || read_line(fp, line, LINE_MAX))) {
got = 0;
if (strncmp(key, line, strlen(key)) != 0 ||
line[strlen(key)] != ':')
continue;
/* Now we found our specified key */
while (read_line(fp, line, LINE_MAX)) {
/* Leaving key field */
if (line[0] != '\0' && strchr(line + 1, ':') != NULL) {
got = 1;
break;
}
p2 = line;
if ((p = strsep(&p2, "=")) == NULL || p2 == NULL)
continue;
trim_whitespace(p);
if (!strncmp(p, option, strlen(option))) {
trim_whitespace(p2);
strcpy(result, p2);
found = 1;
break;
}
}
}
fclose(fp);
if (!found)
errno = ENOENT;
if (!got)
errno = ENOTDIR;
/*
* If we got no result and were looking for a default
* value, try hard coded defaults.
*/
if (strlen(result) == 0 && strcmp(key, "default") == 0 &&
(cp = pw_default(option)) != NULL)
strlcpy(data, cp, max);
else
strlcpy(data, result, max);
}
void
pw_getpwconf(char *data, size_t max, const struct passwd *pwd,
const char *option)
{
char grpkey[LINE_MAX];
struct group grs, *grp;
char grbuf[1024];
pw_getconf(data, max, pwd->pw_name, option);
/* Try to find an entry for the group */
if (*data == '\0') {
(void)getgrgid_r(pwd->pw_gid, &grs, grbuf, sizeof(grbuf), &grp);
if (grp != NULL) {
(void)snprintf(grpkey, sizeof(grpkey), ":%s",
grp->gr_name);
pw_getconf(data, max, grpkey, option);
}
if (*data == '\0')
pw_getconf(data, max, "default", option);
}
}
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