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"
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: "[OPTIONS] [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 Encryption method"
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 #include <sys/resource.h> /* setrlimit */
43
new_password(const struct passwd * pw,uid_t myuid,const char * algo)44 static char* new_password(const struct passwd *pw, uid_t myuid, const char *algo)
45 {
46 char salt[MAX_PW_SALT_LEN];
47 char *orig = (char*)"";
48 char *newp = NULL;
49 char *cp = NULL;
50 char *ret = NULL; /* failure so far */
51
52 if (myuid != 0 && pw->pw_passwd[0]) {
53 char *encrypted;
54
55 orig = bb_ask_stdin("Old password: "); /* returns ptr to static */
56 if (!orig)
57 goto err_ret;
58 encrypted = pw_encrypt(orig, pw->pw_passwd, 1); /* returns malloced str */
59 if (strcmp(encrypted, pw->pw_passwd) != 0) {
60 syslog(LOG_WARNING, "incorrect password for %s", pw->pw_name);
61 bb_do_delay(LOGIN_FAIL_DELAY);
62 puts("Incorrect password");
63 goto err_ret;
64 }
65 if (ENABLE_FEATURE_CLEAN_UP)
66 free(encrypted);
67 }
68 orig = xstrdup(orig); /* or else bb_ask_stdin() will destroy it */
69 newp = bb_ask_stdin("New password: "); /* returns ptr to static */
70 if (!newp)
71 goto err_ret;
72 newp = xstrdup(newp); /* we are going to bb_ask_stdin() again, so save it */
73 if (ENABLE_FEATURE_PASSWD_WEAK_CHECK
74 && obscure(orig, newp, pw)
75 && myuid != 0
76 ) {
77 goto err_ret; /* non-root is not allowed to have weak passwd */
78 }
79
80 cp = bb_ask_stdin("Retype password: ");
81 if (!cp)
82 goto err_ret;
83 if (strcmp(cp, newp) != 0) {
84 puts("Passwords don't match");
85 goto err_ret;
86 }
87
88 crypt_make_pw_salt(salt, algo);
89
90 /* pw_encrypt returns malloced str */
91 ret = pw_encrypt(newp, salt, 1);
92 /* whee, success! */
93
94 err_ret:
95 nuke_str(orig);
96 if (ENABLE_FEATURE_CLEAN_UP) free(orig);
97
98 nuke_str(newp);
99 if (ENABLE_FEATURE_CLEAN_UP) free(newp);
100
101 nuke_str(cp);
102 return ret;
103 }
104
105 int passwd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
passwd_main(int argc UNUSED_PARAM,char ** argv)106 int passwd_main(int argc UNUSED_PARAM, char **argv)
107 {
108 enum {
109 OPT_algo = (1 << 0), /* -a - password algorithm */
110 OPT_lock = (1 << 1), /* -l - lock account */
111 OPT_unlock = (1 << 2), /* -u - unlock account */
112 OPT_delete = (1 << 3), /* -d - delete password */
113 OPT_lud = OPT_lock | OPT_unlock | OPT_delete,
114 };
115 unsigned opt;
116 int rc;
117 const char *opt_a = CONFIG_FEATURE_DEFAULT_PASSWD_ALGO;
118 const char *filename;
119 char *myname;
120 char *name;
121 char *newp;
122 struct passwd *pw;
123 uid_t myuid;
124 struct rlimit rlimit_fsize;
125 char c;
126 #if ENABLE_FEATURE_SHADOWPASSWDS
127 /* Using _r function to avoid pulling in static buffers */
128 struct spwd spw;
129 char buffer[256];
130 #endif
131
132 logmode = LOGMODE_BOTH;
133 openlog(applet_name, 0, LOG_AUTH);
134 opt = getopt32(argv, "a:lud", &opt_a);
135 //argc -= optind;
136 argv += optind;
137
138 myuid = getuid();
139 /* -l, -u, -d require root priv and username argument */
140 if ((opt & OPT_lud) && (myuid != 0 || !argv[0]))
141 bb_show_usage();
142
143 /* Will complain and die if username not found */
144 myname = xstrdup(xuid2uname(myuid));
145 name = argv[0] ? argv[0] : myname;
146
147 pw = xgetpwnam(name);
148 if (myuid != 0 && pw->pw_uid != myuid) {
149 /* LOGMODE_BOTH */
150 bb_error_msg_and_die("%s can't change password for %s", myname, name);
151 }
152
153 #if ENABLE_FEATURE_SHADOWPASSWDS
154 {
155 /* getspnam_r may return 0 yet set result to NULL.
156 * At least glibc 2.4 does this. Be extra paranoid here. */
157 struct spwd *result = NULL;
158 errno = 0;
159 if (getspnam_r(pw->pw_name, &spw, buffer, sizeof(buffer), &result) != 0
160 || !result /* no error, but no record found either */
161 || strcmp(result->sp_namp, pw->pw_name) != 0 /* paranoia */
162 ) {
163 if (errno != ENOENT) {
164 /* LOGMODE_BOTH */
165 bb_perror_msg("no record of %s in %s, using %s",
166 name, bb_path_shadow_file,
167 bb_path_passwd_file);
168 }
169 /* else: /etc/shadow does not exist,
170 * apparently we are on a shadow-less system,
171 * no surprise there */
172 } else {
173 pw->pw_passwd = result->sp_pwdp;
174 }
175 }
176 #endif
177
178 /* Decide what the new password will be */
179 newp = NULL;
180 c = pw->pw_passwd[0] - '!';
181 if (!(opt & OPT_lud)) {
182 if (myuid != 0 && !c) { /* passwd starts with '!' */
183 /* LOGMODE_BOTH */
184 bb_error_msg_and_die("can't change "
185 "locked password for %s", name);
186 }
187 printf("Changing password for %s\n", name);
188 newp = new_password(pw, myuid, opt_a);
189 if (!newp) {
190 logmode = LOGMODE_STDIO;
191 bb_error_msg_and_die("password for %s is unchanged", name);
192 }
193 } else if (opt & OPT_lock) {
194 if (!c)
195 goto skip; /* passwd starts with '!' */
196 newp = xasprintf("!%s", pw->pw_passwd);
197 } else if (opt & OPT_unlock) {
198 if (c)
199 goto skip; /* not '!' */
200 /* pw->pw_passwd points to static storage,
201 * strdup'ing to avoid nasty surprizes */
202 newp = xstrdup(&pw->pw_passwd[1]);
203 } else if (opt & OPT_delete) {
204 newp = (char*)"";
205 }
206
207 rlimit_fsize.rlim_cur = rlimit_fsize.rlim_max = 512L * 30000;
208 setrlimit(RLIMIT_FSIZE, &rlimit_fsize);
209 bb_signals(0
210 + (1 << SIGHUP)
211 + (1 << SIGINT)
212 + (1 << SIGQUIT)
213 , SIG_IGN);
214 umask(077);
215 xsetuid(0);
216
217 #if ENABLE_FEATURE_SHADOWPASSWDS
218 filename = bb_path_shadow_file;
219 rc = update_passwd(bb_path_shadow_file, name, newp, NULL);
220 if (rc > 0)
221 /* password in /etc/shadow was updated */
222 newp = (char*) "x";
223 if (rc >= 0)
224 /* 0 = /etc/shadow missing (not an error), >0 = passwd changed in /etc/shadow */
225 #endif
226 {
227 filename = bb_path_passwd_file;
228 rc = update_passwd(bb_path_passwd_file, name, newp, NULL);
229 }
230 /* LOGMODE_BOTH */
231 if (rc < 0)
232 bb_error_msg_and_die("can't update password file %s", filename);
233 bb_error_msg("password for %s changed by %s", name, myname);
234
235 /*if (ENABLE_FEATURE_CLEAN_UP) free(newp); - can't, it may be non-malloced */
236 skip:
237 if (!newp) {
238 bb_error_msg_and_die("password for %s is already %slocked",
239 name, (opt & OPT_unlock) ? "un" : "");
240 }
241
242 if (ENABLE_FEATURE_CLEAN_UP)
243 free(myname);
244 return 0;
245 }
246