summaryrefslogtreecommitdiff
path: root/loginutils/passwd.c
blob: 2f85e9f217cf89d9b43b9a5ab29e7ae04b912681 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
/* vi: set sw=4 ts=4: */
/*
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

#include "libbb.h"
#include <syslog.h>

static void nuke_str(char *str)
{
	if (str) memset(str, 0, strlen(str));
}

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;
	}

	crypt_make_salt(salt, 1, 0); /* des */
	if (algo) { /* MD5 */
		strcpy(salt, "$1$");
		crypt_make_salt(salt + 3, 4, 0);
	}
	/* pw_encrypt returns ptr to static */
	ret = xstrdup(pw_encrypt(newp, salt));
	/* 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;
}

int passwd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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;
	int rc;
	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;
#if ENABLE_FEATURE_SHADOWPASSWDS
	/* Using _r function to avoid pulling in static buffers */
	struct spwd spw;
	char buffer[256];
#endif

	logmode = LOGMODE_BOTH;
	openlog(applet_name, LOG_NOWAIT, LOG_AUTH);
	opt = getopt32(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();
	/* -l, -u, -d require root priv and username argument */
	if ((opt & OPT_lud) && (myuid || !argv[0]))
		bb_show_usage();

	/* Will complain and die if username not found */
	myname = xstrdup(bb_getpwuid(NULL, -1, myuid));
	name = argv[0] ? 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);
	}

#if ENABLE_FEATURE_SHADOWPASSWDS
	{
		/* getspnam_r may return 0 yet set result to NULL.
		 * At least glibc 2.4 does this. Be extra paranoid here. */
		struct spwd *result = NULL;
		if (getspnam_r(pw->pw_name, &spw, buffer, sizeof(buffer), &result)
		 || !result || strcmp(result->sp_namp, pw->pw_name) != 0) {
			/* LOGMODE_BOTH */
			bb_error_msg("no record of %s in %s, using %s",
					name, bb_path_shadow_file,
					bb_path_passwd_file);
		} else {
			pw->pw_passwd = result->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 '!' */
		/* pw->pw_passwd points to static storage,
		 * strdup'ing to avoid nasty surprizes */
		newp = xstrdup(&pw->pw_passwd[1]);
	} else if (opt & OPT_delete) {
		//newp = xstrdup("");
		newp = (char*)"";
	}

	rlimit_fsize.rlim_cur = rlimit_fsize.rlim_max = 512L * 30000;
	setrlimit(RLIMIT_FSIZE, &rlimit_fsize);
	bb_signals(0
		+ (1 << SIGHUP)
		+ (1 << SIGINT)
		+ (1 << SIGQUIT)
		, SIG_IGN);
	umask(077);
	xsetuid(0);

#if ENABLE_FEATURE_SHADOWPASSWDS
	filename = bb_path_shadow_file;
	rc = update_passwd(bb_path_shadow_file, name, newp);
	if (rc == 0) /* no lines updated, no errors detected */
#endif
	{
		filename = bb_path_passwd_file;
		rc = update_passwd(bb_path_passwd_file, name, newp);
	}
	/* LOGMODE_BOTH */
	if (rc < 0)
		bb_error_msg_and_die("cannot update password file %s",
				filename);
	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;
}