blob: 52b66ca50508fbe68f5af72c2635b6e65ee4ec62
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 | |
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; |
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 |