1 | /* vi: set sw=4 ts=4: */
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2 | /*
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3 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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4 | */
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5 | //config:config PASSWD
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6 | //config: bool "passwd"
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7 | //config: default y
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8 | //config: select FEATURE_SYSLOG
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9 | //config: help
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10 | //config: passwd changes passwords for user and group accounts. A normal user
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11 | //config: may only change the password for his/her own account, the super user
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12 | //config: may change the password for any account. The administrator of a group
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13 | //config: may change the password for the group.
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14 | //config:
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15 | //config: Note that Busybox binary must be setuid root for this applet to
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16 | //config: work properly.
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17 | //config:
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18 | //config:config FEATURE_PASSWD_WEAK_CHECK
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19 | //config: bool "Check new passwords for weakness"
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20 | //config: default y
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21 | //config: depends on PASSWD
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22 | //config: help
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23 | //config: With this option passwd will refuse new passwords which are "weak".
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24 |
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25 | //applet:/* Needs to be run by root or be suid root - needs to change /etc/{passwd,shadow}: */
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26 | //applet:IF_PASSWD(APPLET(passwd, BB_DIR_USR_BIN, BB_SUID_REQUIRE))
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27 |
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28 | //kbuild:lib-$(CONFIG_PASSWD) += passwd.o
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29 |
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30 | //usage:#define passwd_trivial_usage
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31 | //usage: "[OPTIONS] [USER]"
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32 | //usage:#define passwd_full_usage "\n\n"
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33 | //usage: "Change USER's password (default: current user)"
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34 | //usage: "\n"
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35 | //usage: "\n -a ALG Encryption method"
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36 | //usage: "\n -d Set password to ''"
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37 | //usage: "\n -l Lock (disable) account"
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38 | //usage: "\n -u Unlock (enable) account"
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39 |
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40 | #include "libbb.h"
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41 | #include <syslog.h>
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42 | #include <sys/resource.h> /* setrlimit */
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43 |
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44 | static char* new_password(const struct passwd *pw, uid_t myuid, const char *algo)
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45 | {
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46 | char salt[MAX_PW_SALT_LEN];
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47 | char *orig = (char*)"";
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48 | char *newp = NULL;
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49 | char *cp = NULL;
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50 | char *ret = NULL; /* failure so far */
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51 |
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52 | if (myuid != 0 && pw->pw_passwd[0]) {
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53 | char *encrypted;
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54 |
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55 | orig = bb_ask_stdin("Old password: "); /* returns ptr to static */
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56 | if (!orig)
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57 | goto err_ret;
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58 | encrypted = pw_encrypt(orig, pw->pw_passwd, 1); /* returns malloced str */
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59 | if (strcmp(encrypted, pw->pw_passwd) != 0) {
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60 | syslog(LOG_WARNING, "incorrect password for %s", pw->pw_name);
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61 | bb_do_delay(LOGIN_FAIL_DELAY);
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62 | puts("Incorrect password");
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63 | goto err_ret;
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64 | }
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65 | if (ENABLE_FEATURE_CLEAN_UP)
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66 | free(encrypted);
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67 | }
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68 | orig = xstrdup(orig); /* or else bb_ask_stdin() will destroy it */
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69 | newp = bb_ask_stdin("New password: "); /* returns ptr to static */
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70 | if (!newp)
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71 | goto err_ret;
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72 | newp = xstrdup(newp); /* we are going to bb_ask_stdin() again, so save it */
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73 | if (ENABLE_FEATURE_PASSWD_WEAK_CHECK
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74 | && obscure(orig, newp, pw)
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75 | && myuid != 0
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76 | ) {
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77 | goto err_ret; /* non-root is not allowed to have weak passwd */
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78 | }
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79 |
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80 | cp = bb_ask_stdin("Retype password: ");
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81 | if (!cp)
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82 | goto err_ret;
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83 | if (strcmp(cp, newp) != 0) {
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84 | puts("Passwords don't match");
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85 | goto err_ret;
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86 | }
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87 |
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88 | crypt_make_pw_salt(salt, algo);
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89 |
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90 | /* pw_encrypt returns malloced str */
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91 | ret = pw_encrypt(newp, salt, 1);
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92 | /* whee, success! */
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93 |
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94 | err_ret:
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95 | nuke_str(orig);
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96 | if (ENABLE_FEATURE_CLEAN_UP) free(orig);
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97 |
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98 | nuke_str(newp);
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99 | if (ENABLE_FEATURE_CLEAN_UP) free(newp);
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100 |
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101 | nuke_str(cp);
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102 | return ret;
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103 | }
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104 |
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105 | int passwd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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106 | int passwd_main(int argc UNUSED_PARAM, char **argv)
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107 | {
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108 | enum {
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109 | OPT_algo = (1 << 0), /* -a - password algorithm */
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110 | OPT_lock = (1 << 1), /* -l - lock account */
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111 | OPT_unlock = (1 << 2), /* -u - unlock account */
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112 | OPT_delete = (1 << 3), /* -d - delete password */
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113 | OPT_lud = OPT_lock | OPT_unlock | OPT_delete,
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114 | };
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115 | unsigned opt;
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116 | int rc;
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117 | const char *opt_a = CONFIG_FEATURE_DEFAULT_PASSWD_ALGO;
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118 | const char *filename;
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119 | char *myname;
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120 | char *name;
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121 | char *newp;
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122 | struct passwd *pw;
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123 | uid_t myuid;
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124 | struct rlimit rlimit_fsize;
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125 | char c;
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126 | #if ENABLE_FEATURE_SHADOWPASSWDS
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127 | /* Using _r function to avoid pulling in static buffers */
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128 | struct spwd spw;
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129 | char buffer[256];
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130 | #endif
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131 |
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132 | logmode = LOGMODE_BOTH;
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133 | openlog(applet_name, 0, LOG_AUTH);
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134 | opt = getopt32(argv, "a:lud", &opt_a);
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135 | //argc -= optind;
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136 | argv += optind;
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137 |
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138 | myuid = getuid();
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139 | /* -l, -u, -d require root priv and username argument */
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140 | if ((opt & OPT_lud) && (myuid != 0 || !argv[0]))
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141 | bb_show_usage();
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142 |
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143 | /* Will complain and die if username not found */
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144 | myname = xstrdup(xuid2uname(myuid));
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145 | name = argv[0] ? argv[0] : myname;
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146 |
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147 | pw = xgetpwnam(name);
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148 | if (myuid != 0 && pw->pw_uid != myuid) {
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149 | /* LOGMODE_BOTH */
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150 | bb_error_msg_and_die("%s can't change password for %s", myname, name);
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151 | }
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152 |
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153 | #if ENABLE_FEATURE_SHADOWPASSWDS
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154 | {
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155 | /* getspnam_r may return 0 yet set result to NULL.
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156 | * At least glibc 2.4 does this. Be extra paranoid here. */
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157 | struct spwd *result = NULL;
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158 | errno = 0;
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159 | if (getspnam_r(pw->pw_name, &spw, buffer, sizeof(buffer), &result) != 0
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160 | || !result /* no error, but no record found either */
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161 | || strcmp(result->sp_namp, pw->pw_name) != 0 /* paranoia */
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162 | ) {
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163 | if (errno != ENOENT) {
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164 | /* LOGMODE_BOTH */
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165 | bb_perror_msg("no record of %s in %s, using %s",
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166 | name, bb_path_shadow_file,
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167 | bb_path_passwd_file);
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168 | }
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169 | /* else: /etc/shadow does not exist,
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170 | * apparently we are on a shadow-less system,
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171 | * no surprise there */
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172 | } else {
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173 | pw->pw_passwd = result->sp_pwdp;
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174 | }
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175 | }
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176 | #endif
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177 |
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178 | /* Decide what the new password will be */
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179 | newp = NULL;
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180 | c = pw->pw_passwd[0] - '!';
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181 | if (!(opt & OPT_lud)) {
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182 | if (myuid != 0 && !c) { /* passwd starts with '!' */
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183 | /* LOGMODE_BOTH */
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184 | bb_error_msg_and_die("can't change "
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185 | "locked password for %s", name);
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186 | }
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187 | printf("Changing password for %s\n", name);
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188 | newp = new_password(pw, myuid, opt_a);
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189 | if (!newp) {
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190 | logmode = LOGMODE_STDIO;
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191 | bb_error_msg_and_die("password for %s is unchanged", name);
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192 | }
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193 | } else if (opt & OPT_lock) {
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194 | if (!c)
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195 | goto skip; /* passwd starts with '!' */
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196 | newp = xasprintf("!%s", pw->pw_passwd);
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197 | } else if (opt & OPT_unlock) {
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198 | if (c)
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199 | goto skip; /* not '!' */
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200 | /* pw->pw_passwd points to static storage,
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201 | * strdup'ing to avoid nasty surprizes */
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202 | newp = xstrdup(&pw->pw_passwd[1]);
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203 | } else if (opt & OPT_delete) {
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204 | newp = (char*)"";
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205 | }
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206 |
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207 | rlimit_fsize.rlim_cur = rlimit_fsize.rlim_max = 512L * 30000;
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208 | setrlimit(RLIMIT_FSIZE, &rlimit_fsize);
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209 | bb_signals(0
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210 | + (1 << SIGHUP)
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211 | + (1 << SIGINT)
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212 | + (1 << SIGQUIT)
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213 | , SIG_IGN);
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214 | umask(077);
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215 | xsetuid(0);
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216 |
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217 | #if ENABLE_FEATURE_SHADOWPASSWDS
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218 | filename = bb_path_shadow_file;
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219 | rc = update_passwd(bb_path_shadow_file, name, newp, NULL);
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220 | if (rc > 0)
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221 | /* password in /etc/shadow was updated */
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222 | newp = (char*) "x";
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223 | if (rc >= 0)
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224 | /* 0 = /etc/shadow missing (not an error), >0 = passwd changed in /etc/shadow */
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225 | #endif
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226 | {
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227 | filename = bb_path_passwd_file;
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228 | rc = update_passwd(bb_path_passwd_file, name, newp, NULL);
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229 | }
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230 | /* LOGMODE_BOTH */
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231 | if (rc < 0)
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232 | bb_error_msg_and_die("can't update password file %s", filename);
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233 | bb_error_msg("password for %s changed by %s", name, myname);
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234 |
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235 | /*if (ENABLE_FEATURE_CLEAN_UP) free(newp); - can't, it may be non-malloced */
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236 | skip:
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237 | if (!newp) {
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238 | bb_error_msg_and_die("password for %s is already %slocked",
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239 | name, (opt & OPT_unlock) ? "un" : "");
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240 | }
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241 |
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242 | if (ENABLE_FEATURE_CLEAN_UP)
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243 | free(myname);
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244 | return 0;
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245 | }
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