summaryrefslogtreecommitdiff
path: root/runit/chpst.c
blob: 2e94a37c0f02c7045947ee7581b5fb4f51625de1 (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
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
/*
Copyright (c) 2001-2006, Gerrit Pape
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

   1. Redistributions of source code must retain the above copyright notice,
      this list of conditions and the following disclaimer.
   2. Redistributions in binary form must reproduce the above copyright
      notice, this list of conditions and the following disclaimer in the
      documentation and/or other materials provided with the distribution.
   3. The name of the author may not be used to endorse or promote products
      derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

/* Busyboxed by Denys Vlasenko <vda.linux@googlemail.com> */

//config:config CHPST
//config:	bool "chpst (8.7 kb)"
//config:	default y
//config:	help
//config:	  chpst changes the process state according to the given options, and
//config:	  execs specified program.
//config:
//config:config SETUIDGID
//config:	bool "setuidgid (4.2 kb)"
//config:	default y
//config:	help
//config:	  Sets soft resource limits as specified by options
//config:
//config:config ENVUIDGID
//config:	bool "envuidgid (3.6 kb)"
//config:	default y
//config:	help
//config:	  Sets $UID to account's uid and $GID to account's gid
//config:
//config:config ENVDIR
//config:	bool "envdir (2.5 kb)"
//config:	default y
//config:	help
//config:	  Sets various environment variables as specified by files
//config:	  in the given directory
//config:
//config:config SOFTLIMIT
//config:	bool "softlimit (4.3 kb)"
//config:	default y
//config:	help
//config:	  Sets soft resource limits as specified by options

//applet:IF_CHPST(APPLET(chpst, BB_DIR_USR_BIN, BB_SUID_DROP))
//                    APPLET_ODDNAME:name       main   location        suid_type     help
//applet:IF_ENVDIR(   APPLET_ODDNAME(envdir,    chpst, BB_DIR_USR_BIN, BB_SUID_DROP, envdir))
//applet:IF_ENVUIDGID(APPLET_ODDNAME(envuidgid, chpst, BB_DIR_USR_BIN, BB_SUID_DROP, envuidgid))
//applet:IF_SETUIDGID(APPLET_ODDNAME(setuidgid, chpst, BB_DIR_USR_BIN, BB_SUID_DROP, setuidgid))
//applet:IF_SOFTLIMIT(APPLET_ODDNAME(softlimit, chpst, BB_DIR_USR_BIN, BB_SUID_DROP, softlimit))

//kbuild:lib-$(CONFIG_CHPST) += chpst.o
//kbuild:lib-$(CONFIG_ENVDIR) += chpst.o
//kbuild:lib-$(CONFIG_ENVUIDGID) += chpst.o
//kbuild:lib-$(CONFIG_SETUIDGID) += chpst.o
//kbuild:lib-$(CONFIG_SOFTLIMIT) += chpst.o

//usage:#define chpst_trivial_usage
//usage:       "[-vP012] [-u USER[:GRP]] [-U USER[:GRP]] [-e DIR]\n"
//usage:       "	[-/ DIR] [-n NICE] [-m BYTES] [-d BYTES] [-o N]\n"
//usage:       "	[-p N] [-f BYTES] [-c BYTES] PROG ARGS"
//usage:#define chpst_full_usage "\n\n"
//usage:       "Change the process state, run PROG\n"
//usage:     "\n	-u USER[:GRP]	Set uid and gid"
//usage:     "\n	-U USER[:GRP]	Set $UID and $GID in environment"
//usage:     "\n	-e DIR		Set environment variables as specified by files"
//usage:     "\n			in DIR: file=1st_line_of_file"
//usage:     "\n	-/ DIR		Chroot to DIR"
//usage:     "\n	-n NICE		Add NICE to nice value"
//usage:     "\n	-m BYTES	Same as -d BYTES -s BYTES -l BYTES"
//usage:     "\n	-d BYTES	Limit data segment"
//usage:     "\n	-o N		Limit number of open files per process"
//usage:     "\n	-p N		Limit number of processes per uid"
//usage:     "\n	-f BYTES	Limit output file sizes"
//usage:     "\n	-c BYTES	Limit core file size"
//usage:     "\n	-v		Verbose"
//usage:     "\n	-P		Create new process group"
//usage:     "\n	-0		Close stdin"
//usage:     "\n	-1		Close stdout"
//usage:     "\n	-2		Close stderr"
//usage:
//usage:#define envdir_trivial_usage
//usage:       "DIR PROG ARGS"
//usage:#define envdir_full_usage "\n\n"
//usage:       "Set various environment variables as specified by files\n"
//usage:       "in the directory DIR, run PROG"
//usage:
//usage:#define envuidgid_trivial_usage
//usage:       "USER PROG ARGS"
//usage:#define envuidgid_full_usage "\n\n"
//usage:       "Set $UID to USER's uid and $GID to USER's gid, run PROG"
//usage:
//usage:#define setuidgid_trivial_usage
//usage:       "USER PROG ARGS"
//usage:#define setuidgid_full_usage "\n\n"
//usage:       "Set uid and gid to USER's uid and gid, drop supplementary group ids,\n"
//usage:       "run PROG"
//usage:
//usage:#define softlimit_trivial_usage
//usage:       "[-a BYTES] [-m BYTES] [-d BYTES] [-s BYTES] [-l BYTES]\n"
//usage:       "	[-f BYTES] [-c BYTES] [-r BYTES] [-o N] [-p N] [-t N]\n"
//usage:       "	PROG ARGS"
//usage:#define softlimit_full_usage "\n\n"
//usage:       "Set soft resource limits, then run PROG\n"
//usage:     "\n	-a BYTES	Limit total size of all segments"
//usage:     "\n	-m BYTES	Same as -d BYTES -s BYTES -l BYTES -a BYTES"
//usage:     "\n	-d BYTES	Limit data segment"
//usage:     "\n	-s BYTES	Limit stack segment"
//usage:     "\n	-l BYTES	Limit locked memory size"
//usage:     "\n	-o N		Limit number of open files per process"
//usage:     "\n	-p N		Limit number of processes per uid"
//usage:     "\nOptions controlling file sizes:"
//usage:     "\n	-f BYTES	Limit output file sizes"
//usage:     "\n	-c BYTES	Limit core file size"
//usage:     "\nEfficiency opts:"
//usage:     "\n	-r BYTES	Limit resident set size"
//usage:     "\n	-t N		Limit CPU time, process receives"
//usage:     "\n			a SIGXCPU after N seconds"

#include "libbb.h"
#include <sys/resource.h> /* getrlimit */

/*
Five applets here: chpst, envdir, envuidgid, setuidgid, softlimit.

Only softlimit and chpst are taking options:

# common
-o N            Limit number of open files per process
-p N            Limit number of processes per uid
-m BYTES        Same as -d BYTES -s BYTES -l BYTES [-a BYTES]
-d BYTES        Limit data segment
-f BYTES        Limit output file sizes
-c BYTES        Limit core file size
# softlimit
-a BYTES        Limit total size of all segments
-s BYTES        Limit stack segment
-l BYTES        Limit locked memory size
-r BYTES        Limit resident set size
-t N            Limit CPU time
# chpst
-u USER[:GRP]   Set uid and gid
-U USER[:GRP]   Set $UID and $GID in environment
-e DIR          Set environment variables as specified by files in DIR
-/ DIR          Chroot to DIR
-n NICE         Add NICE to nice value
-v              Verbose
-P              Create new process group
-0 -1 -2        Close fd 0,1,2

Even though we accept all these options for both softlimit and chpst,
they are not to be advertised on their help texts.
We have enough problems with feature creep in other people's
software, don't want to add our own.

envdir, envuidgid, setuidgid take no options, but they reuse code which
handles -e, -U and -u.
*/

enum {
	OPT_a = (1 << 0) * ENABLE_SOFTLIMIT,
	OPT_c = (1 << 1) * (ENABLE_SOFTLIMIT || ENABLE_CHPST),
	OPT_d = (1 << 2) * (ENABLE_SOFTLIMIT || ENABLE_CHPST),
	OPT_f = (1 << 3) * (ENABLE_SOFTLIMIT || ENABLE_CHPST),
	OPT_l = (1 << 4) * ENABLE_SOFTLIMIT,
	OPT_m = (1 << 5) * (ENABLE_SOFTLIMIT || ENABLE_CHPST),
	OPT_o = (1 << 6) * (ENABLE_SOFTLIMIT || ENABLE_CHPST),
	OPT_p = (1 << 7) * (ENABLE_SOFTLIMIT || ENABLE_CHPST),
	OPT_r = (1 << 8) * ENABLE_SOFTLIMIT,
	OPT_s = (1 << 9) * ENABLE_SOFTLIMIT,
	OPT_t = (1 << 10) * ENABLE_SOFTLIMIT,
	OPT_u = (1 << 11) * (ENABLE_CHPST || ENABLE_SETUIDGID),
	OPT_U = (1 << 12) * (ENABLE_CHPST || ENABLE_ENVUIDGID),
	OPT_e = (1 << 13) * (ENABLE_CHPST || ENABLE_ENVDIR),
	OPT_root = (1 << 14) * ENABLE_CHPST,
	OPT_n = (1 << 15) * ENABLE_CHPST,
	OPT_v = (1 << 16) * ENABLE_CHPST,
	OPT_P = (1 << 17) * ENABLE_CHPST,
	OPT_0 = (1 << 18) * ENABLE_CHPST,
	OPT_1 = (1 << 19) * ENABLE_CHPST,
	OPT_2 = (1 << 20) * ENABLE_CHPST,
};

/* TODO: use recursive_action? */
static NOINLINE void edir(const char *directory_name)
{
	int wdir;
	DIR *dir;
	struct dirent *d;
	int fd;

	wdir = xopen(".", O_RDONLY | O_NDELAY);
	xchdir(directory_name);
	dir = xopendir(".");
	for (;;) {
		char buf[256];
		char *tail;
		int size;

		errno = 0;
		d = readdir(dir);
		if (!d) {
			if (errno)
				bb_perror_msg_and_die("readdir %s",
						directory_name);
			break;
		}
		if (d->d_name[0] == '.')
			continue;
		fd = open(d->d_name, O_RDONLY | O_NDELAY);
		if (fd < 0) {
			if ((errno == EISDIR) && directory_name) {
				if (option_mask32 & OPT_v)
					bb_perror_msg("warning: %s/%s is a directory",
						directory_name, d->d_name);
				continue;
			}
			bb_perror_msg_and_die("open %s/%s",
						directory_name, d->d_name);
		}
		size = full_read(fd, buf, sizeof(buf)-1);
		close(fd);
		if (size < 0)
			bb_perror_msg_and_die("read %s/%s",
					directory_name, d->d_name);
		if (size == 0) {
			unsetenv(d->d_name);
			continue;
		}
		buf[size] = '\n';
		tail = strchr(buf, '\n');
		/* skip trailing whitespace */
		while (1) {
			*tail = '\0';
			tail--;
			if (tail < buf || !isspace(*tail))
				break;
		}
		xsetenv(d->d_name, buf);
	}
	closedir(dir);
	xfchdir(wdir);
	close(wdir);
}

static void limit(int what, long l)
{
	struct rlimit r;

	/* Never fails under Linux (except if you pass it bad arguments) */
	getrlimit(what, &r);
	if ((l < 0) || (l > r.rlim_max))
		r.rlim_cur = r.rlim_max;
	else
		r.rlim_cur = l;
	if (setrlimit(what, &r) == -1)
		bb_perror_msg_and_die("setrlimit");
}

int chpst_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int chpst_main(int argc UNUSED_PARAM, char **argv)
{
	struct bb_uidgid_t ugid;
	char *set_user = set_user; /* for compiler */
	char *env_dir = env_dir;
	char *root;
	char *nicestr;
	unsigned limita;
	unsigned limitc;
	unsigned limitd;
	unsigned limitf;
	unsigned limitl;
	unsigned limitm;
	unsigned limito;
	unsigned limitp;
	unsigned limitr;
	unsigned limits;
	unsigned limitt;
	unsigned opt;

	if ((ENABLE_CHPST && applet_name[0] == 'c')
	 || (ENABLE_SOFTLIMIT && applet_name[1] == 'o')
	) {
		// FIXME: can we live with int-sized limits?
		// can we live with 40000 days?
		// if yes -> getopt converts strings to numbers for us
		opt_complementary = "-1";
		opt = getopt32(argv, "+a:+c:+d:+f:+l:+m:+o:+p:+r:+s:+t:+u:U:e:"
			IF_CHPST("/:n:vP012"),
			&limita, &limitc, &limitd, &limitf, &limitl,
			&limitm, &limito, &limitp, &limitr, &limits, &limitt,
			&set_user, &set_user, &env_dir
			IF_CHPST(, &root, &nicestr));
		argv += optind;
		if (opt & OPT_m) { // -m means -asld
			limita = limits = limitl = limitd = limitm;
			opt |= (OPT_s | OPT_l | OPT_a | OPT_d);
		}
	} else {
		option_mask32 = opt = 0;
		argv++;
		if (!*argv)
			bb_show_usage();
	}

	// envdir?
	if (ENABLE_ENVDIR && applet_name[3] == 'd') {
		env_dir = *argv++;
		opt |= OPT_e;
	}

	// setuidgid?
	if (ENABLE_SETUIDGID && applet_name[1] == 'e') {
		set_user = *argv++;
		opt |= OPT_u;
	}

	// envuidgid?
	if (ENABLE_ENVUIDGID && applet_name[0] == 'e' && applet_name[3] == 'u') {
		set_user = *argv++;
		opt |= OPT_U;
	}

	// we must have PROG [ARGS]
	if (!*argv)
		bb_show_usage();

	// set limits
	if (opt & OPT_d) {
#ifdef RLIMIT_DATA
		limit(RLIMIT_DATA, limitd);
#else
		if (opt & OPT_v)
			bb_error_msg("system does not support RLIMIT_%s",
				"DATA");
#endif
	}
	if (opt & OPT_s) {
#ifdef RLIMIT_STACK
		limit(RLIMIT_STACK, limits);
#else
		if (opt & OPT_v)
			bb_error_msg("system does not support RLIMIT_%s",
				"STACK");
#endif
	}
	if (opt & OPT_l) {
#ifdef RLIMIT_MEMLOCK
		limit(RLIMIT_MEMLOCK, limitl);
#else
		if (opt & OPT_v)
			bb_error_msg("system does not support RLIMIT_%s",
				"MEMLOCK");
#endif
	}
	if (opt & OPT_a) {
#ifdef RLIMIT_VMEM
		limit(RLIMIT_VMEM, limita);
#else
#ifdef RLIMIT_AS
		limit(RLIMIT_AS, limita);
#else
		if (opt & OPT_v)
			bb_error_msg("system does not support RLIMIT_%s",
				"VMEM");
#endif
#endif
	}
	if (opt & OPT_o) {
#ifdef RLIMIT_NOFILE
		limit(RLIMIT_NOFILE, limito);
#else
#ifdef RLIMIT_OFILE
		limit(RLIMIT_OFILE, limito);
#else
		if (opt & OPT_v)
			bb_error_msg("system does not support RLIMIT_%s",
				"NOFILE");
#endif
#endif
	}
	if (opt & OPT_p) {
#ifdef RLIMIT_NPROC
		limit(RLIMIT_NPROC, limitp);
#else
		if (opt & OPT_v)
			bb_error_msg("system does not support RLIMIT_%s",
				"NPROC");
#endif
	}
	if (opt & OPT_f) {
#ifdef RLIMIT_FSIZE
		limit(RLIMIT_FSIZE, limitf);
#else
		if (opt & OPT_v)
			bb_error_msg("system does not support RLIMIT_%s",
				"FSIZE");
#endif
	}
	if (opt & OPT_c) {
#ifdef RLIMIT_CORE
		limit(RLIMIT_CORE, limitc);
#else
		if (opt & OPT_v)
			bb_error_msg("system does not support RLIMIT_%s",
				"CORE");
#endif
	}
	if (opt & OPT_r) {
#ifdef RLIMIT_RSS
		limit(RLIMIT_RSS, limitr);
#else
		if (opt & OPT_v)
			bb_error_msg("system does not support RLIMIT_%s",
				"RSS");
#endif
	}
	if (opt & OPT_t) {
#ifdef RLIMIT_CPU
		limit(RLIMIT_CPU, limitt);
#else
		if (opt & OPT_v)
			bb_error_msg("system does not support RLIMIT_%s",
				"CPU");
#endif
	}

	if (opt & OPT_P)
		setsid();

	if (opt & OPT_e)
		edir(env_dir);

	if (opt & (OPT_u|OPT_U))
		xget_uidgid(&ugid, set_user);

	// chrooted jail must have /etc/passwd if we move this after chroot.
	// OTOH chroot fails for non-roots.
	// Solution: cache uid/gid before chroot, apply uid/gid after.
	if (opt & OPT_U) {
		xsetenv("GID", utoa(ugid.gid));
		xsetenv("UID", utoa(ugid.uid));
	}

	if (opt & OPT_root) {
		xchroot(root);
	}

	/* nice should be done before xsetuid */
	if (opt & OPT_n) {
		errno = 0;
		if (nice(xatoi(nicestr)) == -1)
			bb_perror_msg_and_die("nice");
	}

	if (opt & OPT_u) {
		if (setgroups(1, &ugid.gid) == -1)
			bb_perror_msg_and_die("setgroups");
		xsetgid(ugid.gid);
		xsetuid(ugid.uid);
	}

	if (opt & OPT_0)
		close(STDIN_FILENO);
	if (opt & OPT_1)
		close(STDOUT_FILENO);
	if (opt & OPT_2)
		close(STDERR_FILENO);

	BB_EXECVP_or_die(argv);
}