mirror of
https://github.com/sheumann/hush.git
synced 2024-08-18 21:29:23 +00:00
298 lines
7.6 KiB
C
298 lines
7.6 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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*/
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#include "busybox.h"
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#include <syslog.h>
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static void nuke_str(char *str)
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{
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if (str) memset(str, 0, strlen(str));
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}
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static char* new_password(const struct passwd *pw, uid_t myuid, int algo)
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{
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char salt[sizeof("$N$XXXXXXXX")]; /* "$N$XXXXXXXX" or "XX" */
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char *orig = (char*)"";
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char *newp = NULL;
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char *cipher = NULL;
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char *cp = NULL;
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char *ret = NULL; /* failure so far */
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if (myuid && pw->pw_passwd[0]) {
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orig = bb_askpass(0, "Old password:"); /* returns ptr to static */
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if (!orig)
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goto err_ret;
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cipher = pw_encrypt(orig, pw->pw_passwd); /* returns ptr to static */
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if (strcmp(cipher, pw->pw_passwd) != 0) {
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syslog(LOG_WARNING, "incorrect password for '%s'",
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pw->pw_name);
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bb_do_delay(FAIL_DELAY);
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puts("Incorrect password");
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goto err_ret;
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}
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}
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orig = xstrdup(orig); /* or else bb_askpass() will destroy it */
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newp = bb_askpass(0, "New password:"); /* returns ptr to static */
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if (!newp)
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goto err_ret;
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newp = xstrdup(newp); /* we are going to bb_askpass() again, so save it */
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if (ENABLE_FEATURE_PASSWD_WEAK_CHECK
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&& obscure(orig, newp, pw) && myuid)
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goto err_ret; /* non-root is not allowed to have weak passwd */
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cp = bb_askpass(0, "Retype password:");
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if (!cp)
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goto err_ret;
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if (strcmp(cp, newp)) {
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puts("Passwords don't match");
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goto err_ret;
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}
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/*memset(salt, 0, sizeof(salt)); - why?*/
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crypt_make_salt(salt, 1); /* des */
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if (algo) { /* MD5 */
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strcpy(salt, "$1$");
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crypt_make_salt(salt + 3, 4);
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}
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ret = xstrdup(pw_encrypt(newp, salt)); /* returns ptr to static */
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/* whee, success! */
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err_ret:
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nuke_str(orig);
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if (ENABLE_FEATURE_CLEAN_UP) free(orig);
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nuke_str(newp);
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if (ENABLE_FEATURE_CLEAN_UP) free(newp);
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nuke_str(cipher);
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nuke_str(cp);
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return ret;
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}
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static int update_passwd(const char *filename, const char *username,
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const char *new_pw)
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{
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struct stat sb;
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struct flock lock;
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FILE *old_fp;
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FILE *new_fp;
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char *new_name;
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char *last_char;
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unsigned user_len;
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int old_fd;
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int new_fd;
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int i;
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int ret = 1; /* failure */
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logmode = LOGMODE_STDIO;
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/* New passwd file, "/etc/passwd+" for now */
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new_name = xasprintf("%s+", filename);
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last_char = &new_name[strlen(new_name)-1];
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username = xasprintf("%s:", username);
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user_len = strlen(username);
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old_fp = fopen(filename, "r+");
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if (!old_fp)
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goto free_mem;
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old_fd = fileno(old_fp);
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/* Try to create "/etc/passwd+". Wait if it exists. */
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i = 30;
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do {
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// FIXME: on last iteration try w/o O_EXCL but with O_TRUNC?
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new_fd = open(new_name, O_WRONLY|O_CREAT|O_EXCL,0600);
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if (new_fd >= 0) goto created;
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if (errno != EEXIST) break;
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usleep(100000); /* 0.1 sec */
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} while (--i);
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bb_perror_msg("cannot create '%s'", new_name);
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goto close_old_fp;
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created:
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if (!fstat(old_fd, &sb)) {
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fchmod(new_fd, sb.st_mode & 0777); /* ignore errors */
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fchown(new_fd, sb.st_uid, sb.st_gid);
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}
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new_fp = fdopen(new_fd, "w");
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if (!new_fp) {
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close(new_fd);
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goto unlink_new;
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}
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/* Backup file is "/etc/passwd-" */
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last_char[0] = '-';
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/* Delete old one, create new as a hardlink to current */
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i = (unlink(new_name) && errno != ENOENT);
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if (i || link(filename, new_name))
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bb_perror_msg("warning: cannot create backup copy '%s'", new_name);
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last_char[0] = '+';
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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(old_fd, F_SETLK, &lock) < 0)
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bb_perror_msg("warning: cannot lock '%s'", filename);
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lock.l_type = F_UNLCK;
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/* Read current password file, write updated one */
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while (1) {
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char *line = xmalloc_fgets(old_fp);
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if (!line) break; /* EOF/error */
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if (strncmp(username, line, user_len) == 0) {
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/* we have a match with "username:"... */
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const char *cp = line + user_len;
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/* now cp -> old passwd, skip it: */
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cp = strchr(cp, ':');
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if (!cp) cp = "";
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/* now cp -> ':' after old passwd or -> "" */
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fprintf(new_fp, "%s%s%s", username, new_pw, cp);
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/* Erase password in memory */
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} else
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fputs(line, new_fp);
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free(line);
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}
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fcntl(old_fd, F_SETLK, &lock);
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/* We do want all of them to execute, thus | instead of || */
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if ((ferror(old_fp) | fflush(new_fp) | fsync(new_fd) | fclose(new_fp))
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|| rename(new_name, filename)
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) {
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/* At least one of those failed */
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goto unlink_new;
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}
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ret = 0; /* whee, success! */
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unlink_new:
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if (ret) unlink(new_name);
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close_old_fp:
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fclose(old_fp);
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free_mem:
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if (ENABLE_FEATURE_CLEAN_UP) free(new_name);
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if (ENABLE_FEATURE_CLEAN_UP) free((char*)username);
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logmode = LOGMODE_BOTH;
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return ret;
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}
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int passwd_main(int argc, char **argv);
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int passwd_main(int argc, char **argv)
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{
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enum {
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OPT_algo = 0x1, /* -a - password algorithm */
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OPT_lock = 0x2, /* -l - lock account */
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OPT_unlock = 0x4, /* -u - unlock account */
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OPT_delete = 0x8, /* -d - delete password */
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OPT_lud = 0xe,
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STATE_ALGO_md5 = 0x10,
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/*STATE_ALGO_des = 0x20, not needed yet */
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};
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unsigned opt;
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const char *opt_a = "";
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const char *filename;
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char *myname;
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char *name;
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char *newp;
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struct passwd *pw;
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uid_t myuid;
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struct rlimit rlimit_fsize;
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char c;
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#if ENABLE_FEATURE_SHADOWPASSWDS
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/* Using _r function to avoid pulling in static buffers */
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struct spwd spw;
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struct spwd *result;
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char buffer[256];
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#endif
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logmode = LOGMODE_BOTH;
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openlog(applet_name, LOG_NOWAIT, LOG_AUTH);
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opt = getopt32(argc, argv, "a:lud", &opt_a);
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argc -= optind;
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argv += optind;
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if (strcasecmp(opt_a, "des") != 0) /* -a */
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opt |= STATE_ALGO_md5;
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//else
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// opt |= STATE_ALGO_des;
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myuid = getuid();
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if ((opt & OPT_lud) && (!argc || myuid))
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bb_show_usage();
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myname = xstrdup(bb_getpwuid(NULL, myuid, -1));
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name = argc ? argv[0] : myname;
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pw = getpwnam(name);
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if (!pw) bb_error_msg_and_die("unknown user %s", name);
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if (myuid && pw->pw_uid != myuid) {
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/* LOGMODE_BOTH */
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bb_error_msg_and_die("%s can't change password for %s", myname, name);
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}
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filename = bb_path_passwd_file;
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#if ENABLE_FEATURE_SHADOWPASSWDS
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if (getspnam_r(pw->pw_name, &spw, buffer, sizeof(buffer), &result)) {
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/* LOGMODE_BOTH */
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bb_error_msg("no record of %s in %s, using %s",
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name, bb_path_shadow_file,
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bb_path_passwd_file);
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} else {
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filename = bb_path_shadow_file;
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pw->pw_passwd = spw.sp_pwdp;
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}
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#endif
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/* Decide what the new password will be */
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newp = NULL;
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c = pw->pw_passwd[0] - '!';
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if (!(opt & OPT_lud)) {
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if (myuid && !c) { /* passwd starts with '!' */
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/* LOGMODE_BOTH */
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bb_error_msg_and_die("cannot change "
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"locked password for %s", name);
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}
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printf("Changing password for %s\n", name);
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newp = new_password(pw, myuid, opt & STATE_ALGO_md5);
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if (!newp) {
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logmode = LOGMODE_STDIO;
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bb_error_msg_and_die("password for %s is unchanged", name);
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}
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} else if (opt & OPT_lock) {
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if (!c) goto skip; /* passwd starts with '!' */
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newp = xasprintf("!%s", pw->pw_passwd);
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} else if (opt & OPT_unlock) {
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if (c) goto skip; /* not '!' */
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newp = xstrdup(&pw->pw_passwd[1]);
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} else if (opt & OPT_delete) {
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newp = xstrdup("");
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}
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rlimit_fsize.rlim_cur = rlimit_fsize.rlim_max = 512L * 30000;
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setrlimit(RLIMIT_FSIZE, &rlimit_fsize);
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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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xsetuid(0);
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if (update_passwd(filename, name, newp) != 0) {
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/* LOGMODE_BOTH */
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bb_error_msg_and_die("cannot update password file %s",
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filename);
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}
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/* LOGMODE_BOTH */
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bb_info_msg("Password for %s changed by %s", name, myname);
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if (ENABLE_FEATURE_CLEAN_UP) free(newp);
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skip:
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if (!newp) {
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bb_error_msg_and_die("password for %s is already %slocked",
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name, (opt & OPT_unlock) ? "un" : "");
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}
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if (ENABLE_FEATURE_CLEAN_UP) free(myname);
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return 0;
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}
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