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