busybox/loginutils/passwd.c

/* vi: set sw=4 ts=4: */
/*
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

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


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


static int i64c(int i)
{
	i &= 0x3f;
	if (i == 0)
		return '.';
	if (i == 1)
		return '/';
	if (i < 12)
		return ('0' - 2 + i);
	if (i < 38)
		return ('A' - 12 + i);
	return ('a' - 38 + i);
}


static void crypt_make_salt(char *p, int cnt)
{
	unsigned x = x; /* it's pointless to initialize it anyway :) */

	x += getpid() + time(NULL) + clock();
	do {
		/* x = (x*1664525 + 1013904223) % 2^32 generator is lame
		 * (low-order bit is not "random", etc...),
		 * but for our purposes it is good enough */
		x = x*1664525 + 1013904223;
		/* BTW, Park and Miller's "minimal standard generator" is
		 * x = x*16807 % ((2^31)-1)
		 * It has no problem with visibly alternating lowest bit
		 * but is also weak in cryptographic sense + needs div,
		 * which needs more code (and slower) on many CPUs */
		*p++ = i64c(x >> 16);
		*p++ = i64c(x >> 22);
	} while (--cnt);
	*p = '\0';
}


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 *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;
	}

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


#if 0
static int get_algo(char *a)
{
	/* standard: MD5 */
	int x = 1;
	if (strcasecmp(a, "des") == 0)
		x = 0;
	return x;
}
#endif


static int update_passwd(const char *filename, const char *username,
			const char *new_pw)
{
	struct stat sb;
	struct flock lock;
	FILE *old_fp;
	FILE *new_fp;
	char *new_name;
	char *last_char;
	unsigned user_len;
	int old_fd;
	int new_fd;
	int i;
	int ret = 1; /* failure */

	logmode = LOGMODE_STDIO;
	/* New passwd file, "/etc/passwd+" for now */
	new_name = xasprintf("%s+", filename);
	last_char = &new_name[strlen(new_name)-1];
	username = xasprintf("%s:", username);
	user_len = strlen(username);

	old_fp = fopen(filename, "r+");
	if (!old_fp)
		goto free_mem;
	old_fd = fileno(old_fp);

	/* Try to create "/etc/passwd+". Wait if it exists. */
	i = 30;
	do {
		// FIXME: on last iteration try w/o O_EXCL but with O_TRUNC?
		new_fd = open(new_name, O_WRONLY|O_CREAT|O_EXCL,0600);
		if (new_fd >= 0) goto created;
		if (errno != EEXIST) break;
		usleep(100000); /* 0.1 sec */
	} while (--i);
	bb_perror_msg("cannot create '%s'", new_name);
	goto close_old_fp;
 created:
	if (!fstat(old_fd, &sb)) {
		fchmod(new_fd, sb.st_mode & 0777); /* ignore errors */
		fchown(new_fd, sb.st_uid, sb.st_gid);
	}
	new_fp = fdopen(new_fd, "w");
	if (!new_fp) {
		close(new_fd);
		goto unlink_new;
	}

	/* Backup file is "/etc/passwd-" */
	last_char[0] = '-';
	/* Delete old one, create new as a hardlink to current */
	i = (unlink(new_name) && errno != ENOENT);
	if (i || link(filename, new_name))
		bb_perror_msg("warning: cannot create backup copy '%s'", new_name);
	last_char[0] = '+';

	/* Lock the password file before updating */
	lock.l_type = F_WRLCK;
	lock.l_whence = SEEK_SET;
	lock.l_start = 0;
	lock.l_len = 0;
	if (fcntl(old_fd, F_SETLK, &lock) < 0)
		bb_perror_msg("warning: cannot lock '%s'", filename);
	lock.l_type = F_UNLCK;

	/* Read current password file, write updated one */
	while (1) {
		char *line = xmalloc_fgets(old_fp);
		if (!line) break; /* EOF/error */
		if (strncmp(username, line, user_len) == 0) {
			/* we have a match with "username:"... */
			const char *cp = line + user_len;
			/* now cp -> old passwd, skip it: */
			cp = strchr(cp, ':');
			if (!cp) cp = "";
			/* now cp -> ':' after old passwd or -> "" */
			fprintf(new_fp, "%s%s%s", username, new_pw, cp);
			/* Erase password in memory */
		} else
			fputs(line, new_fp);
		free(line);
	}
	fcntl(old_fd, F_SETLK, &lock);

	/* We do want all of them to execute, thus | instead of || */
	if ((ferror(old_fp) | fflush(new_fp) | fsync(new_fd) | fclose(new_fp))
	 || rename(new_name, filename)
	) {
		/* At least one of those failed */
		goto unlink_new;
	}
	ret = 0; /* whee, success! */

 unlink_new:
	if (ret) unlink(new_name);

 close_old_fp:
	fclose(old_fp);

 free_mem:
	if (ENABLE_FEATURE_CLEAN_UP) free(new_name);
	if (ENABLE_FEATURE_CLEAN_UP) free((char*)username);
	logmode = LOGMODE_BOTH;
	return ret;
}


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;
	char *opt_a = "";
	const char *filename;
	char *myname;
	char *name;
	char *newp;
	struct passwd *pw;
	uid_t myuid;
	struct rlimit rlimit_fsize;
	char c;

	logmode = LOGMODE_BOTH;
	openlog(applet_name, LOG_NOWAIT, LOG_AUTH);
	opt = getopt32(argc, 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();
	if ((opt & OPT_lud) && (!argc || myuid))
		bb_show_usage();

	myname = xstrdup(bb_getpwuid(NULL, myuid, -1));
	name = argc ? 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);
	}

	filename = bb_path_passwd_file;
#if ENABLE_FEATURE_SHADOWPASSWDS
	{
		struct spwd *sp = getspnam(name);
		if (!sp) {
			/* LOGMODE_BOTH */
			bb_error_msg("no record of %s in %s, using %s",
					name, bb_path_shadow_file,
					bb_path_passwd_file);
		} else {
			filename = bb_path_shadow_file;
			pw->pw_passwd = sp->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 '!' */
		newp = xstrdup(&pw->pw_passwd[1]);
	} else if (opt & OPT_delete) {
		newp = xstrdup("");
	}

	rlimit_fsize.rlim_cur = rlimit_fsize.rlim_max = 512L * 30000;
	setrlimit(RLIMIT_FSIZE, &rlimit_fsize);
	signal(SIGHUP, SIG_IGN);
	signal(SIGINT, SIG_IGN);
	signal(SIGQUIT, SIG_IGN);
	umask(077);
	xsetuid(0);
	if (update_passwd(filename, name, newp) != 0) {
		/* LOGMODE_BOTH */
		bb_error_msg_and_die("cannot update password file %s",
				filename);
	}
	/* LOGMODE_BOTH */
	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;
}
1	/* vi: set sw=4 ts=4: */
2	/*
3	* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
4	*/
5
6	#include "busybox.h"
7	#include <syslog.h>
8
9
10	static void nuke_str(char *str)
11	{
12	if (str) memset(str, 0, strlen(str));
13	}
14
15
16	static int i64c(int i)
17	{
18	i &= 0x3f;
19	if (i == 0)
20	return '.';
21	if (i == 1)
22	return '/';
23	if (i < 12)
24	return ('0' - 2 + i);
25	if (i < 38)
26	return ('A' - 12 + i);
27	return ('a' - 38 + i);
28	}
29
30
31	static void crypt_make_salt(char *p, int cnt)
32	{
33	unsigned x = x; /* it's pointless to initialize it anyway :) */
34
35	x += getpid() + time(NULL) + clock();
36	do {
37	/* x = (x*1664525 + 1013904223) % 2^32 generator is lame
38	* (low-order bit is not "random", etc...),
39	* but for our purposes it is good enough */
40	x = x*1664525 + 1013904223;
41	/* BTW, Park and Miller's "minimal standard generator" is
42	* x = x*16807 % ((2^31)-1)
43	* It has no problem with visibly alternating lowest bit
44	* but is also weak in cryptographic sense + needs div,
45	* which needs more code (and slower) on many CPUs */
46	*p++ = i64c(x >> 16);
47	*p++ = i64c(x >> 22);
48	} while (--cnt);
49	*p = '\0';
50	}
51
52
53	static char* new_password(const struct passwd *pw, uid_t myuid, int algo)
54	{
55	char salt[sizeof("$N$XXXXXXXX")]; /* "$N$XXXXXXXX" or "XX" */
56	char *orig = "";
57	char *newp = NULL;
58	char *cipher = NULL;
59	char *cp = NULL;
60	char ret = NULL; / failure so far */
61
62	if (myuid && pw->pw_passwd[0]) {
63	orig = bb_askpass(0, "Old password:"); /* returns ptr to static */
64	if (!orig)
65	goto err_ret;
66	cipher = pw_encrypt(orig, pw->pw_passwd); /* returns ptr to static */
67	if (strcmp(cipher, pw->pw_passwd) != 0) {
68	syslog(LOG_WARNING, "incorrect password for '%s'",
69	pw->pw_name);
70	bb_do_delay(FAIL_DELAY);
71	puts("Incorrect password");
72	goto err_ret;
73	}
74	}
75	orig = xstrdup(orig); /* or else bb_askpass() will destroy it */
76	newp = bb_askpass(0, "New password:"); /* returns ptr to static */
77	if (!newp)
78	goto err_ret;
79	newp = xstrdup(newp); /* we are going to bb_askpass() again, so save it */
80	if (ENABLE_FEATURE_PASSWD_WEAK_CHECK
81	&& obscure(orig, newp, pw) && myuid)
82	goto err_ret; /* non-root is not allowed to have weak passwd */
83
84	cp = bb_askpass(0, "Retype password:");
85	if (!cp)
86	goto err_ret;
87	if (strcmp(cp, newp)) {
88	puts("Passwords don't match");
89	goto err_ret;
90	}
91
92	/memset(salt, 0, sizeof(salt)); - why?/
93	crypt_make_salt(salt, 1); /* des */
94	if (algo) { /* MD5 */
95	strcpy(salt, "$1$");
96	crypt_make_salt(salt + 3, 4);
97	}
98	ret = xstrdup(pw_encrypt(newp, salt)); /* returns ptr to static */
99	/* whee, success! */
100
101	err_ret:
102	nuke_str(orig);
103	if (ENABLE_FEATURE_CLEAN_UP) free(orig);
104	nuke_str(newp);
105	if (ENABLE_FEATURE_CLEAN_UP) free(newp);
106	nuke_str(cipher);
107	nuke_str(cp);
108	return ret;
109	}
110
111
112	#if 0
113	static int get_algo(char *a)
114	{
115	/* standard: MD5 */
116	int x = 1;
117	if (strcasecmp(a, "des") == 0)
118	x = 0;
119	return x;
120	}
121	#endif
122
123
124	static int update_passwd(const char filename, const char username,
125	const char *new_pw)
126	{
127	struct stat sb;
128	struct flock lock;
129	FILE *old_fp;
130	FILE *new_fp;
131	char *new_name;
132	char *last_char;
133	unsigned user_len;
134	int old_fd;
135	int new_fd;
136	int i;
137	int ret = 1; /* failure */
138
139	logmode = LOGMODE_STDIO;
140	/* New passwd file, "/etc/passwd+" for now */
141	new_name = xasprintf("%s+", filename);
142	last_char = &new_name[strlen(new_name)-1];
143	username = xasprintf("%s:", username);
144	user_len = strlen(username);
145
146	old_fp = fopen(filename, "r+");
147	if (!old_fp)
148	goto free_mem;
149	old_fd = fileno(old_fp);
150
151	/* Try to create "/etc/passwd+". Wait if it exists. */
152	i = 30;
153	do {
154	// FIXME: on last iteration try w/o O_EXCL but with O_TRUNC?
155	new_fd = open(new_name, O_WRONLY\|O_CREAT\|O_EXCL,0600);
156	if (new_fd >= 0) goto created;
157	if (errno != EEXIST) break;
158	usleep(100000); /* 0.1 sec */
159	} while (--i);
160	bb_perror_msg("cannot create '%s'", new_name);
161	goto close_old_fp;
162	created:
163	if (!fstat(old_fd, &sb)) {
164	fchmod(new_fd, sb.st_mode & 0777); /* ignore errors */
165	fchown(new_fd, sb.st_uid, sb.st_gid);
166	}
167	new_fp = fdopen(new_fd, "w");
168	if (!new_fp) {
169	close(new_fd);
170	goto unlink_new;
171	}
172
173	/* Backup file is "/etc/passwd-" */
174	last_char[0] = '-';
175	/* Delete old one, create new as a hardlink to current */
176	i = (unlink(new_name) && errno != ENOENT);
177	if (i \|\| link(filename, new_name))
178	bb_perror_msg("warning: cannot create backup copy '%s'", new_name);
179	last_char[0] = '+';
180
181	/* Lock the password file before updating */
182	lock.l_type = F_WRLCK;
183	lock.l_whence = SEEK_SET;
184	lock.l_start = 0;
185	lock.l_len = 0;
186	if (fcntl(old_fd, F_SETLK, &lock) < 0)
187	bb_perror_msg("warning: cannot lock '%s'", filename);
188	lock.l_type = F_UNLCK;
189
190	/* Read current password file, write updated one */
191	while (1) {
192	char *line = xmalloc_fgets(old_fp);
193	if (!line) break; /* EOF/error */
194	if (strncmp(username, line, user_len) == 0) {
195	/* we have a match with "username:"... */
196	const char *cp = line + user_len;
197	/* now cp -> old passwd, skip it: */
198	cp = strchr(cp, ':');
199	if (!cp) cp = "";
200	/* now cp -> ':' after old passwd or -> "" */
201	fprintf(new_fp, "%s%s%s", username, new_pw, cp);
202	/* Erase password in memory */
203	} else
204	fputs(line, new_fp);
205	free(line);
206	}
207	fcntl(old_fd, F_SETLK, &lock);
208
209	/* We do want all of them to execute, thus \| instead of \|\| */
210	if ((ferror(old_fp) \| fflush(new_fp) \| fsync(new_fd) \| fclose(new_fp))
211	\|\| rename(new_name, filename)
212	) {
213	/* At least one of those failed */
214	goto unlink_new;
215	}
216	ret = 0; /* whee, success! */
217
218	unlink_new:
219	if (ret) unlink(new_name);
220
221	close_old_fp:
222	fclose(old_fp);
223
224	free_mem:
225	if (ENABLE_FEATURE_CLEAN_UP) free(new_name);
226	if (ENABLE_FEATURE_CLEAN_UP) free((char*)username);
227	logmode = LOGMODE_BOTH;
228	return ret;
229	}
230
231
232	int passwd_main(int argc, char **argv)
233	{
234	enum {
235	OPT_algo = 0x1, /* -a - password algorithm */
236	OPT_lock = 0x2, /* -l - lock account */
237	OPT_unlock = 0x4, /* -u - unlock account */
238	OPT_delete = 0x8, /* -d - delete password */
239	OPT_lud = 0xe,
240	STATE_ALGO_md5 = 0x10,
241	/STATE_ALGO_des = 0x20, not needed yet /
242	};
243	unsigned opt;
244	char *opt_a = "";
245	const char *filename;
246	char *myname;
247	char *name;
248	char *newp;
249	struct passwd *pw;
250	uid_t myuid;
251	struct rlimit rlimit_fsize;
252	char c;
253
254	logmode = LOGMODE_BOTH;
255	openlog(applet_name, LOG_NOWAIT, LOG_AUTH);
256	opt = getopt32(argc, argv, "a:lud", &opt_a);
257	argc -= optind;
258	argv += optind;
259
260	if (strcasecmp(opt_a, "des") != 0) /* -a */
261	opt \|= STATE_ALGO_md5;
262	//else
263	// opt \|= STATE_ALGO_des;
264	myuid = getuid();
265	if ((opt & OPT_lud) && (!argc \|\| myuid))
266	bb_show_usage();
267
268	myname = xstrdup(bb_getpwuid(NULL, myuid, -1));
269	name = argc ? argv[0] : myname;
270
271	pw = getpwnam(name);
272	if (!pw) bb_error_msg_and_die("unknown user %s", name);
273	if (myuid && pw->pw_uid != myuid) {
274	/* LOGMODE_BOTH */
275	bb_error_msg_and_die("%s can't change password for %s", myname, name);
276	}
277
278	filename = bb_path_passwd_file;
279	#if ENABLE_FEATURE_SHADOWPASSWDS
280	{
281	struct spwd *sp = getspnam(name);
282	if (!sp) {
283	/* LOGMODE_BOTH */
284	bb_error_msg("no record of %s in %s, using %s",
285	name, bb_path_shadow_file,
286	bb_path_passwd_file);
287	} else {
288	filename = bb_path_shadow_file;
289	pw->pw_passwd = sp->sp_pwdp;
290	}
291	}
292	#endif
293
294	/* Decide what the new password will be */
295	newp = NULL;
296	c = pw->pw_passwd[0] - '!';
297	if (!(opt & OPT_lud)) {
298	if (myuid && !c) { /* passwd starts with '!' */
299	/* LOGMODE_BOTH */
300	bb_error_msg_and_die("cannot change "
301	"locked password for %s", name);
302	}
303	printf("Changing password for %s\n", name);
304	newp = new_password(pw, myuid, opt & STATE_ALGO_md5);
305	if (!newp) {
306	logmode = LOGMODE_STDIO;
307	bb_error_msg_and_die("password for %s is unchanged", name);
308	}
309	} else if (opt & OPT_lock) {
310	if (!c) goto skip; /* passwd starts with '!' */
311	newp = xasprintf("!%s", pw->pw_passwd);
312	} else if (opt & OPT_unlock) {
313	if (c) goto skip; /* not '!' */
314	newp = xstrdup(&pw->pw_passwd[1]);
315	} else if (opt & OPT_delete) {
316	newp = xstrdup("");
317	}
318
319	rlimit_fsize.rlim_cur = rlimit_fsize.rlim_max = 512L * 30000;
320	setrlimit(RLIMIT_FSIZE, &rlimit_fsize);
321	signal(SIGHUP, SIG_IGN);
322	signal(SIGINT, SIG_IGN);
323	signal(SIGQUIT, SIG_IGN);
324	umask(077);
325	xsetuid(0);
326	if (update_passwd(filename, name, newp) != 0) {
327	/* LOGMODE_BOTH */
328	bb_error_msg_and_die("cannot update password file %s",
329	filename);
330	}
331	/* LOGMODE_BOTH */
332	bb_info_msg("Password for %s changed by %s", name, myname);
333
334	if (ENABLE_FEATURE_CLEAN_UP) free(newp);
335	skip:
336	if (!newp) {
337	bb_error_msg_and_die("password for %s is already %slocked",
338	name, (opt & OPT_unlock) ? "un" : "");
339	}
340	if (ENABLE_FEATURE_CLEAN_UP) free(myname);
341	return 0;
342	}