| /* vi: set sw=4 ts=4: */ |
| /* |
| * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. |
| */ |
| |
| #include "busybox.h" |
| #include <syslog.h> |
| |
| |
| static void nuke_str(char *str) |
| { |
| if (str) memset(str, 0, strlen(str)); |
| } |
| |
| |
| static int i64c(int i) |
| { |
| i &= 0x3f; |
| if (i == 0) |
| return '.'; |
| if (i == 1) |
| return '/'; |
| if (i < 12) |
| return ('0' - 2 + i); |
| if (i < 38) |
| return ('A' - 12 + i); |
| return ('a' - 38 + i); |
| } |
| |
| |
| static void crypt_make_salt(char *p, int cnt) |
| { |
| unsigned x = x; /* it's pointless to initialize it anyway :) */ |
| |
| x += getpid() + time(NULL) + clock(); |
| do { |
| /* x = (x*1664525 + 1013904223) % 2^32 generator is lame |
| * (low-order bit is not "random", etc...), |
| * but for our purposes it is good enough */ |
| x = x*1664525 + 1013904223; |
| /* BTW, Park and Miller's "minimal standard generator" is |
| * x = x*16807 % ((2^31)-1) |
| * It has no problem with visibly alternating lowest bit |
| * but is also weak in cryptographic sense + needs div, |
| * which needs more code (and slower) on many CPUs */ |
| *p++ = i64c(x >> 16); |
| *p++ = i64c(x >> 22); |
| } while (--cnt); |
| *p = '\0'; |
| } |
| |
| |
| static char* new_password(const struct passwd *pw, uid_t myuid, int algo) |
| { |
| char salt[sizeof("$N$XXXXXXXX")]; /* "$N$XXXXXXXX" or "XX" */ |
| char *orig = (char*)""; |
| char *newp = NULL; |
| char *cipher = NULL; |
| char *cp = NULL; |
| char *ret = NULL; /* failure so far */ |
| |
| if (myuid && pw->pw_passwd[0]) { |
| orig = bb_askpass(0, "Old password:"); /* returns ptr to static */ |
| if (!orig) |
| goto err_ret; |
| cipher = pw_encrypt(orig, pw->pw_passwd); /* returns ptr to static */ |
| if (strcmp(cipher, pw->pw_passwd) != 0) { |
| syslog(LOG_WARNING, "incorrect password for '%s'", |
| pw->pw_name); |
| bb_do_delay(FAIL_DELAY); |
| puts("Incorrect password"); |
| goto err_ret; |
| } |
| } |
| orig = xstrdup(orig); /* or else bb_askpass() will destroy it */ |
| newp = bb_askpass(0, "New password:"); /* returns ptr to static */ |
| if (!newp) |
| goto err_ret; |
| newp = xstrdup(newp); /* we are going to bb_askpass() again, so save it */ |
| if (ENABLE_FEATURE_PASSWD_WEAK_CHECK |
| && obscure(orig, newp, pw) && myuid) |
| goto err_ret; /* non-root is not allowed to have weak passwd */ |
| |
| cp = bb_askpass(0, "Retype password:"); |
| if (!cp) |
| goto err_ret; |
| if (strcmp(cp, newp)) { |
| puts("Passwords don't match"); |
| goto err_ret; |
| } |
| |
| /*memset(salt, 0, sizeof(salt)); - why?*/ |
| crypt_make_salt(salt, 1); /* des */ |
| if (algo) { /* MD5 */ |
| strcpy(salt, "$1$"); |
| crypt_make_salt(salt + 3, 4); |
| } |
| ret = xstrdup(pw_encrypt(newp, salt)); /* returns ptr to static */ |
| /* whee, success! */ |
| |
| err_ret: |
| nuke_str(orig); |
| if (ENABLE_FEATURE_CLEAN_UP) free(orig); |
| nuke_str(newp); |
| if (ENABLE_FEATURE_CLEAN_UP) free(newp); |
| nuke_str(cipher); |
| nuke_str(cp); |
| return ret; |
| } |
| |
| |
| #if 0 |
| static int get_algo(char *a) |
| { |
| /* standard: MD5 */ |
| int x = 1; |
| if (strcasecmp(a, "des") == 0) |
| x = 0; |
| return x; |
| } |
| #endif |
| |
| |
| static int update_passwd(const char *filename, const char *username, |
| const char *new_pw) |
| { |
| struct stat sb; |
| struct flock lock; |
| FILE *old_fp; |
| FILE *new_fp; |
| char *new_name; |
| char *last_char; |
| unsigned user_len; |
| int old_fd; |
| int new_fd; |
| int i; |
| int ret = 1; /* failure */ |
| |
| logmode = LOGMODE_STDIO; |
| /* New passwd file, "/etc/passwd+" for now */ |
| new_name = xasprintf("%s+", filename); |
| last_char = &new_name[strlen(new_name)-1]; |
| username = xasprintf("%s:", username); |
| user_len = strlen(username); |
| |
| old_fp = fopen(filename, "r+"); |
| if (!old_fp) |
| goto free_mem; |
| old_fd = fileno(old_fp); |
| |
| /* Try to create "/etc/passwd+". Wait if it exists. */ |
| i = 30; |
| do { |
| // FIXME: on last iteration try w/o O_EXCL but with O_TRUNC? |
| new_fd = open(new_name, O_WRONLY|O_CREAT|O_EXCL,0600); |
| if (new_fd >= 0) goto created; |
| if (errno != EEXIST) break; |
| usleep(100000); /* 0.1 sec */ |
| } while (--i); |
| bb_perror_msg("cannot create '%s'", new_name); |
| goto close_old_fp; |
| created: |
| if (!fstat(old_fd, &sb)) { |
| fchmod(new_fd, sb.st_mode & 0777); /* ignore errors */ |
| fchown(new_fd, sb.st_uid, sb.st_gid); |
| } |
| new_fp = fdopen(new_fd, "w"); |
| if (!new_fp) { |
| close(new_fd); |
| goto unlink_new; |
| } |
| |
| /* Backup file is "/etc/passwd-" */ |
| last_char[0] = '-'; |
| /* Delete old one, create new as a hardlink to current */ |
| i = (unlink(new_name) && errno != ENOENT); |
| if (i || link(filename, new_name)) |
| bb_perror_msg("warning: cannot create backup copy '%s'", new_name); |
| last_char[0] = '+'; |
| |
| /* Lock the password file before updating */ |
| lock.l_type = F_WRLCK; |
| lock.l_whence = SEEK_SET; |
| lock.l_start = 0; |
| lock.l_len = 0; |
| if (fcntl(old_fd, F_SETLK, &lock) < 0) |
| bb_perror_msg("warning: cannot lock '%s'", filename); |
| lock.l_type = F_UNLCK; |
| |
| /* Read current password file, write updated one */ |
| while (1) { |
| char *line = xmalloc_fgets(old_fp); |
| if (!line) break; /* EOF/error */ |
| if (strncmp(username, line, user_len) == 0) { |
| /* we have a match with "username:"... */ |
| const char *cp = line + user_len; |
| /* now cp -> old passwd, skip it: */ |
| cp = strchr(cp, ':'); |
| if (!cp) cp = ""; |
| /* now cp -> ':' after old passwd or -> "" */ |
| fprintf(new_fp, "%s%s%s", username, new_pw, cp); |
| /* Erase password in memory */ |
| } else |
| fputs(line, new_fp); |
| free(line); |
| } |
| fcntl(old_fd, F_SETLK, &lock); |
| |
| /* We do want all of them to execute, thus | instead of || */ |
| if ((ferror(old_fp) | fflush(new_fp) | fsync(new_fd) | fclose(new_fp)) |
| || rename(new_name, filename) |
| ) { |
| /* At least one of those failed */ |
| goto unlink_new; |
| } |
| ret = 0; /* whee, success! */ |
| |
| unlink_new: |
| if (ret) unlink(new_name); |
| |
| close_old_fp: |
| fclose(old_fp); |
| |
| free_mem: |
| if (ENABLE_FEATURE_CLEAN_UP) free(new_name); |
| if (ENABLE_FEATURE_CLEAN_UP) free((char*)username); |
| logmode = LOGMODE_BOTH; |
| return ret; |
| } |
| |
| |
| int passwd_main(int argc, char **argv); |
| int passwd_main(int argc, char **argv) |
| { |
| enum { |
| OPT_algo = 0x1, /* -a - password algorithm */ |
| OPT_lock = 0x2, /* -l - lock account */ |
| OPT_unlock = 0x4, /* -u - unlock account */ |
| OPT_delete = 0x8, /* -d - delete password */ |
| OPT_lud = 0xe, |
| STATE_ALGO_md5 = 0x10, |
| /*STATE_ALGO_des = 0x20, not needed yet */ |
| }; |
| unsigned opt; |
| const char *opt_a = ""; |
| const char *filename; |
| char *myname; |
| char *name; |
| char *newp; |
| struct passwd *pw; |
| uid_t myuid; |
| struct rlimit rlimit_fsize; |
| char c; |
| |
| logmode = LOGMODE_BOTH; |
| openlog(applet_name, LOG_NOWAIT, LOG_AUTH); |
| opt = getopt32(argc, argv, "a:lud", &opt_a); |
| argc -= optind; |
| argv += optind; |
| |
| if (strcasecmp(opt_a, "des") != 0) /* -a */ |
| opt |= STATE_ALGO_md5; |
| //else |
| // opt |= STATE_ALGO_des; |
| myuid = getuid(); |
| if ((opt & OPT_lud) && (!argc || myuid)) |
| bb_show_usage(); |
| |
| myname = xstrdup(bb_getpwuid(NULL, myuid, -1)); |
| name = argc ? argv[0] : myname; |
| |
| pw = getpwnam(name); |
| if (!pw) bb_error_msg_and_die("unknown user %s", name); |
| if (myuid && pw->pw_uid != myuid) { |
| /* LOGMODE_BOTH */ |
| bb_error_msg_and_die("%s can't change password for %s", myname, name); |
| } |
| |
| filename = bb_path_passwd_file; |
| #if ENABLE_FEATURE_SHADOWPASSWDS |
| { |
| struct spwd *sp = getspnam(name); |
| if (!sp) { |
| /* LOGMODE_BOTH */ |
| bb_error_msg("no record of %s in %s, using %s", |
| name, bb_path_shadow_file, |
| bb_path_passwd_file); |
| } else { |
| filename = bb_path_shadow_file; |
| pw->pw_passwd = sp->sp_pwdp; |
| } |
| } |
| #endif |
| |
| /* Decide what the new password will be */ |
| newp = NULL; |
| c = pw->pw_passwd[0] - '!'; |
| if (!(opt & OPT_lud)) { |
| if (myuid && !c) { /* passwd starts with '!' */ |
| /* LOGMODE_BOTH */ |
| bb_error_msg_and_die("cannot change " |
| "locked password for %s", name); |
| } |
| printf("Changing password for %s\n", name); |
| newp = new_password(pw, myuid, opt & STATE_ALGO_md5); |
| if (!newp) { |
| logmode = LOGMODE_STDIO; |
| bb_error_msg_and_die("password for %s is unchanged", name); |
| } |
| } else if (opt & OPT_lock) { |
| if (!c) goto skip; /* passwd starts with '!' */ |
| newp = xasprintf("!%s", pw->pw_passwd); |
| } else if (opt & OPT_unlock) { |
| if (c) goto skip; /* not '!' */ |
| newp = xstrdup(&pw->pw_passwd[1]); |
| } else if (opt & OPT_delete) { |
| newp = xstrdup(""); |
| } |
| |
| rlimit_fsize.rlim_cur = rlimit_fsize.rlim_max = 512L * 30000; |
| setrlimit(RLIMIT_FSIZE, &rlimit_fsize); |
| signal(SIGHUP, SIG_IGN); |
| signal(SIGINT, SIG_IGN); |
| signal(SIGQUIT, SIG_IGN); |
| umask(077); |
| xsetuid(0); |
| if (update_passwd(filename, name, newp) != 0) { |
| /* LOGMODE_BOTH */ |
| bb_error_msg_and_die("cannot update password file %s", |
| filename); |
| } |
| /* LOGMODE_BOTH */ |
| bb_info_msg("Password for %s changed by %s", name, myname); |
| |
| if (ENABLE_FEATURE_CLEAN_UP) free(newp); |
| skip: |
| if (!newp) { |
| bb_error_msg_and_die("password for %s is already %slocked", |
| name, (opt & OPT_unlock) ? "un" : ""); |
| } |
| if (ENABLE_FEATURE_CLEAN_UP) free(myname); |
| return 0; |
| } |