mirror of
https://github.com/sheumann/hush.git
synced 2024-10-29 20:27:40 +00:00
407 lines
8.9 KiB
C
407 lines
8.9 KiB
C
/* vi: set sw=4 ts=4: */
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#include <fcntl.h>
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#include <stdio.h>
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#include <string.h>
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#include <signal.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include <utime.h>
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#include <syslog.h>
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#include <time.h>
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#include <sys/resource.h>
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#include <errno.h>
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#include "busybox.h"
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static char crypt_passwd[128];
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static int create_backup(const char *backup, FILE * fp);
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static int new_password(const struct passwd *pw, int amroot, int algo);
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static void set_filesize_limit(int blocks);
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int get_algo(char *a)
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{
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int x = 1; /* standard: MD5 */
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if (strcasecmp(a, "des") == 0)
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x = 0;
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return x;
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}
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extern int update_passwd(const struct passwd *pw, char *crypt_pw)
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{
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char filename[1024];
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char buf[1025];
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char buffer[80];
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char username[32];
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char *pw_rest;
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int has_shadow = 0;
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int mask;
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int continued;
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FILE *fp;
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FILE *out_fp;
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struct stat sb;
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struct flock lock;
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if (access(bb_path_shadow_file, F_OK) == 0) {
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has_shadow = 1;
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}
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if (has_shadow) {
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snprintf(filename, sizeof filename, "%s", bb_path_shadow_file);
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} else {
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snprintf(filename, sizeof filename, "%s", bb_path_passwd_file);
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}
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if (((fp = fopen(filename, "r+")) == 0) || (fstat(fileno(fp), &sb))) {
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/* return 0; */
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return 1;
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}
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/* Lock the password file before updating */
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lock.l_type = F_WRLCK;
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lock.l_whence = SEEK_SET;
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lock.l_start = 0;
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lock.l_len = 0;
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if (fcntl(fileno(fp), F_SETLK, &lock) < 0) {
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fprintf(stderr, "%s: %s\n", filename, strerror(errno));
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return 1;
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}
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lock.l_type = F_UNLCK;
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snprintf(buf, sizeof buf, "%s-", filename);
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if (create_backup(buf, fp)) {
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fcntl(fileno(fp), F_SETLK, &lock);
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fclose(fp);
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return 1;
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}
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snprintf(buf, sizeof buf, "%s+", filename);
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mask = umask(0777);
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out_fp = fopen(buf, "w");
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umask(mask);
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if ((!out_fp) || (fchmod(fileno(out_fp), sb.st_mode & 0777))
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|| (fchown(fileno(out_fp), sb.st_uid, sb.st_gid))) {
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fcntl(fileno(fp), F_SETLK, &lock);
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fclose(fp);
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fclose(out_fp);
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return 1;
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}
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continued = 0;
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snprintf(username, sizeof username, "%s:", pw->pw_name);
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rewind(fp);
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while (!feof(fp)) {
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fgets(buffer, sizeof buffer, fp);
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if (!continued) { // Check to see if we're updating this line.
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if (strncmp(username, buffer, strlen(username)) == 0) { // we have a match.
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pw_rest = strchr(buffer, ':');
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*pw_rest++ = '\0';
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pw_rest = strchr(pw_rest, ':');
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fprintf(out_fp, "%s:%s%s", buffer, crypt_pw, pw_rest);
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} else {
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fputs(buffer, out_fp);
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}
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} else {
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fputs(buffer, out_fp);
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}
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if (buffer[strlen(buffer) - 1] == '\n') {
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continued = 0;
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} else {
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continued = 1;
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}
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bzero(buffer, sizeof buffer);
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}
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if (fflush(out_fp) || fsync(fileno(out_fp)) || fclose(out_fp)) {
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unlink(buf);
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fcntl(fileno(fp), F_SETLK, &lock);
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fclose(fp);
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return 1;
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}
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if (rename(buf, filename) < 0) {
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fcntl(fileno(fp), F_SETLK, &lock);
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fclose(fp);
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return 1;
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} else {
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fcntl(fileno(fp), F_SETLK, &lock);
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fclose(fp);
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return 0;
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}
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}
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extern int passwd_main(int argc, char **argv)
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{
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int amroot;
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char *cp;
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char *np;
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char *name;
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char *myname;
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int flag;
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int algo = 0; /* -a - password algorithm */
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int lflg = 0; /* -l - lock account */
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int uflg = 0; /* -u - unlock account */
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int dflg = 0; /* -d - delete password */
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const struct passwd *pw;
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unsigned short ruid;
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#ifdef CONFIG_FEATURE_SHADOWPASSWDS
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const struct spwd *sp;
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#endif /* CONFIG_FEATURE_SHADOWPASSWDS */
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amroot = (getuid() == 0);
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openlog("passwd", LOG_PID | LOG_CONS | LOG_NOWAIT, LOG_AUTH);
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while ((flag = getopt(argc, argv, "a:dlu")) != EOF) {
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switch (flag) {
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case 'a':
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algo = get_algo(optarg);
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break;
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case 'd':
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dflg++;
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break;
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case 'l':
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lflg++;
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break;
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case 'u':
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uflg++;
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break;
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default:
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bb_show_usage();
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}
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}
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ruid = getuid();
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pw = (struct passwd *) getpwuid(ruid);
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if (!pw) {
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bb_error_msg_and_die("Cannot determine your user name.");
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}
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myname = (char *) bb_xstrdup(pw->pw_name);
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if (optind < argc) {
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name = argv[optind];
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} else {
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name = myname;
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}
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if ((lflg || uflg || dflg) && (optind >= argc || !amroot)) {
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bb_show_usage();
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}
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pw = getpwnam(name);
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if (!pw) {
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bb_error_msg_and_die("Unknown user %s\n", name);
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}
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if (!amroot && pw->pw_uid != getuid()) {
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syslog(LOG_WARNING, "can't change pwd for `%s'", name);
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bb_error_msg_and_die("Permission denied.\n");
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}
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#ifdef CONFIG_FEATURE_SHADOWPASSWDS
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sp = getspnam(name);
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if (!sp) {
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sp = (struct spwd *) pwd_to_spwd(pw);
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}
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cp = sp->sp_pwdp;
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np = sp->sp_namp;
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#else
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cp = pw->pw_passwd;
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np = name;
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#endif /* CONFIG_FEATURE_SHADOWPASSWDS */
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safe_strncpy(crypt_passwd, cp, sizeof(crypt_passwd));
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if (!(dflg || lflg || uflg)) {
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if (!amroot) {
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if (cp[0] == '!') {
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syslog(LOG_WARNING, "password locked for `%s'", np);
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bb_error_msg_and_die( "The password for `%s' cannot be changed.\n", np);
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}
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}
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printf("Changing password for %s\n", name);
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if (new_password(pw, amroot, algo)) {
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bb_error_msg_and_die( "The password for %s is unchanged.\n", name);
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}
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} else if (lflg) {
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if (crypt_passwd[0] != '!') {
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memmove(&crypt_passwd[1], crypt_passwd,
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sizeof crypt_passwd - 1);
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crypt_passwd[sizeof crypt_passwd - 1] = '\0';
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crypt_passwd[0] = '!';
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}
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} else if (uflg) {
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if (crypt_passwd[0] == '!') {
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memmove(crypt_passwd, &crypt_passwd[1],
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sizeof crypt_passwd - 1);
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}
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} else if (dflg) {
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crypt_passwd[0] = '\0';
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}
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set_filesize_limit(30000);
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signal(SIGHUP, SIG_IGN);
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signal(SIGINT, SIG_IGN);
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signal(SIGQUIT, SIG_IGN);
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umask(077);
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if (setuid(0)) {
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syslog(LOG_ERR, "can't setuid(0)");
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bb_error_msg_and_die( "Cannot change ID to root.\n");
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}
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if (!update_passwd(pw, crypt_passwd)) {
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syslog(LOG_INFO, "password for `%s' changed by user `%s'", name,
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myname);
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printf("Password changed.\n");
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} else {
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syslog(LOG_WARNING, "an error occurred updating the password file");
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bb_error_msg_and_die("An error occurred updating the password file.\n");
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}
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return (0);
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}
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static int create_backup(const char *backup, FILE * fp)
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{
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struct stat sb;
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struct utimbuf ub;
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FILE *bkfp;
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int c, mask;
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if (fstat(fileno(fp), &sb))
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/* return -1; */
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return 1;
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mask = umask(077);
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bkfp = fopen(backup, "w");
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umask(mask);
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if (!bkfp)
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/* return -1; */
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return 1;
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/* TODO: faster copy, not one-char-at-a-time. --marekm */
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rewind(fp);
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while ((c = getc(fp)) != EOF) {
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if (putc(c, bkfp) == EOF)
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break;
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}
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if (c != EOF || fflush(bkfp)) {
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fclose(bkfp);
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/* return -1; */
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return 1;
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}
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if (fclose(bkfp))
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/* return -1; */
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return 1;
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ub.actime = sb.st_atime;
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ub.modtime = sb.st_mtime;
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utime(backup, &ub);
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return 0;
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}
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static int i64c(int i)
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{
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if (i <= 0)
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return ('.');
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if (i == 1)
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return ('/');
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if (i >= 2 && i < 12)
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return ('0' - 2 + i);
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if (i >= 12 && i < 38)
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return ('A' - 12 + i);
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if (i >= 38 && i < 63)
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return ('a' - 38 + i);
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return ('z');
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}
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static char *crypt_make_salt(void)
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{
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time_t now;
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static unsigned long x;
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static char result[3];
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time(&now);
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x += now + getpid() + clock();
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result[0] = i64c(((x >> 18) ^ (x >> 6)) & 077);
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result[1] = i64c(((x >> 12) ^ x) & 077);
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result[2] = '\0';
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return result;
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}
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static int new_password(const struct passwd *pw, int amroot, int algo)
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{
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char *clear;
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char *cipher;
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char *cp;
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char orig[200];
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char pass[200];
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time_t start, now;
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if (!amroot && crypt_passwd[0]) {
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if (!(clear = getpass("Old password:"))) {
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/* return -1; */
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return 1;
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}
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cipher = pw_encrypt(clear, crypt_passwd);
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if (strcmp(cipher, crypt_passwd) != 0) {
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syslog(LOG_WARNING, "incorrect password for `%s'",
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pw->pw_name);
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time(&start);
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now = start;
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while (difftime(now, start) < FAIL_DELAY) {
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sleep(FAIL_DELAY);
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time(&now);
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}
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fprintf(stderr, "Incorrect password.\n");
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/* return -1; */
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return 1;
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}
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safe_strncpy(orig, clear, sizeof(orig));
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bzero(clear, strlen(clear));
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bzero(cipher, strlen(cipher));
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} else {
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orig[0] = '\0';
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}
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if (! (cp=getpass("Enter the new password (minimum of 5, maximum of 8 characters)\n"
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"Please use a combination of upper and lower case letters and numbers.\n"
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"Enter new password: ")))
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{
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bzero(orig, sizeof orig);
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/* return -1; */
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return 1;
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}
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safe_strncpy(pass, cp, sizeof(pass));
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bzero(cp, strlen(cp));
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/* if (!obscure(orig, pass, pw)) { */
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if (obscure(orig, pass, pw)) {
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if (amroot) {
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printf("\nWarning: weak password (continuing).\n");
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} else {
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/* return -1; */
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return 1;
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}
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}
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if (!(cp = getpass("Re-enter new password: "))) {
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bzero(orig, sizeof orig);
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/* return -1; */
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return 1;
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}
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if (strcmp(cp, pass)) {
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fprintf(stderr, "Passwords do not match.\n");
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/* return -1; */
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return 1;
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}
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bzero(cp, strlen(cp));
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bzero(orig, sizeof(orig));
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if (algo == 1) {
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cp = pw_encrypt(pass, "$1$");
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} else
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cp = pw_encrypt(pass, crypt_make_salt());
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bzero(pass, sizeof pass);
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safe_strncpy(crypt_passwd, cp, sizeof(crypt_passwd));
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return 0;
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}
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static void set_filesize_limit(int blocks)
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{
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struct rlimit rlimit_fsize;
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rlimit_fsize.rlim_cur = rlimit_fsize.rlim_max = 512L * blocks;
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setrlimit(RLIMIT_FSIZE, &rlimit_fsize);
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}
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