xref: /freebsd/usr.sbin/setfmac/setfmac.c (revision 7ef62cebc2f965b0f640263e179276928885e33d)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2002, 2004 Networks Associates Technology, Inc.
5  * All rights reserved.
6  *
7  * This software was developed for the FreeBSD Project by NAI Labs, the
8  * Security Research Division of Network Associates, Inc. under
9  * DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA
10  * CHATS research program.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions and the following disclaimer.
17  * 2. Redistributions in binary form must reproduce the above copyright
18  *    notice, this list of conditions and the following disclaimer in the
19  *    documentation and/or other materials provided with the distribution.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  * $FreeBSD$
34  */
35 
36 #include <sys/types.h>
37 #include <sys/mac.h>
38 #include <sys/queue.h>
39 #include <sys/stat.h>
40 
41 #include <ctype.h>
42 #include <err.h>
43 #include <errno.h>
44 #include <fts.h>
45 #include <libgen.h>
46 #include <regex.h>
47 #include <stdio.h>
48 #include <stdlib.h>
49 #include <string.h>
50 #include <unistd.h>
51 
52 struct label_spec {
53 	struct label_spec_entry {
54 		regex_t regex;	/* compiled regular expression to match */
55 		char *regexstr;	/* uncompiled regular expression */
56 		mode_t mode;	/* mode to possibly match */
57 		const char *modestr;	/* print-worthy ",-?" mode string */
58 		char *mactext;	/* MAC label to apply */
59 		int flags;	/* miscellaneous flags */
60 #define		F_DONTLABEL	0x01
61 #define		F_ALWAYSMATCH	0x02
62 	} *entries,		/* entries[0..nentries] */
63 	  *match;		/* cached decision for MAC label to apply */
64 	size_t nentries;	/* size of entries list */
65 	STAILQ_ENTRY(label_spec) link;
66 };
67 
68 struct label_specs {
69 	STAILQ_HEAD(label_specs_head, label_spec) head;
70 };
71 
72 void usage(int) __dead2;
73 struct label_specs *new_specs(void);
74 void add_specs(struct label_specs *, const char *, int);
75 void add_setfmac_specs(struct label_specs *, char *);
76 void add_spec_line(const char *, int, struct label_spec_entry *, char *);
77 int apply_specs(struct label_specs *, FTSENT *, int, int);
78 int specs_empty(struct label_specs *);
79 
80 static int qflag;
81 
82 int
83 main(int argc, char **argv)
84 {
85 	FTSENT *ftsent;
86 	FTS *fts;
87 	struct label_specs *specs;
88 	int eflag = 0, xflag = 0, vflag = 0, Rflag = 0, hflag;
89 	int ch, is_setfmac;
90 	char *bn;
91 
92 	bn = basename(argv[0]);
93 	if (bn == NULL)
94 		err(1, "basename");
95 	is_setfmac = strcmp(bn, "setfmac") == 0;
96 	hflag = is_setfmac ? FTS_LOGICAL : FTS_PHYSICAL;
97 	specs = new_specs();
98 	while ((ch = getopt(argc, argv, is_setfmac ? "Rhq" : "ef:qs:vx")) !=
99 	    -1) {
100 		switch (ch) {
101 		case 'R':
102 			Rflag = 1;
103 			break;
104 		case 'e':
105 			eflag = 1;
106 			break;
107 		case 'f':
108 			add_specs(specs, optarg, 0);
109 			break;
110 		case 'h':
111 			hflag = FTS_PHYSICAL;
112 			break;
113 		case 'q':
114 			qflag = 1;
115 			break;
116 		case 's':
117 			add_specs(specs, optarg, 1);
118 			break;
119 		case 'v':
120 			vflag++;
121 			break;
122 		case 'x':
123 			xflag = FTS_XDEV;
124 			break;
125 		default:
126 			usage(is_setfmac);
127 		}
128 	}
129 	argc -= optind;
130 	argv += optind;
131 
132 	if (is_setfmac) {
133 		if (argc <= 1)
134 			usage(is_setfmac);
135 		add_setfmac_specs(specs, *argv);
136 		argc--;
137 		argv++;
138 	} else {
139 		if (argc == 0 || specs_empty(specs))
140 			usage(is_setfmac);
141 	}
142 	fts = fts_open(argv, hflag | xflag, NULL);
143 	if (fts == NULL)
144 		err(1, "cannot traverse filesystem%s", argc ? "s" : "");
145 	while (errno = 0, (ftsent = fts_read(fts)) != NULL) {
146 		switch (ftsent->fts_info) {
147 		case FTS_DP:		/* skip post-order */
148 			break;
149 		case FTS_D:		/* do pre-order */
150 		case FTS_DC:		/* do cyclic? */
151 			/* don't ever recurse directories as setfmac(8) */
152 			if (is_setfmac && !Rflag)
153 				fts_set(fts, ftsent, FTS_SKIP);
154 		case FTS_DEFAULT:	/* do default */
155 		case FTS_F:		/* do regular */
156 		case FTS_SL:		/* do symlink */
157 		case FTS_SLNONE:	/* do symlink */
158 		case FTS_W:		/* do whiteout */
159 			if (apply_specs(specs, ftsent, hflag, vflag)) {
160 				if (eflag) {
161 					errx(1, "labeling not supported in %s",
162 					    ftsent->fts_path);
163 				}
164 				if (!qflag)
165 					warnx("labeling not supported in %s",
166 					    ftsent->fts_path);
167 				fts_set(fts, ftsent, FTS_SKIP);
168 			}
169 			break;
170 		case FTS_DNR:		/* die on all errors */
171 		case FTS_ERR:
172 		case FTS_NS:
173 			err(1, "traversing %s", ftsent->fts_path);
174 		default:
175 			errx(1, "CANNOT HAPPEN (%d) traversing %s",
176 			    ftsent->fts_info, ftsent->fts_path);
177 		}
178 	}
179 	if (errno != 0)
180 		err(1, "fts_read");
181 	fts_close(fts);
182 	exit(0);
183 }
184 
185 void
186 usage(int is_setfmac)
187 {
188 
189 	if (is_setfmac)
190 		fprintf(stderr, "usage: setfmac [-Rhq] label file ...\n");
191 	else
192 		fprintf(stderr, "usage: setfsmac [-ehqvx] [-f specfile [...]] [-s specfile [...]] file ...\n");
193 	exit(1);
194 }
195 
196 static int
197 chomp_line(char **line, size_t *linesize)
198 {
199 	char *s;
200 	int freeme = 0;
201 
202 	for (s = *line; (unsigned)(s - *line) < *linesize; s++) {
203 		if (!isspace(*s))
204 			break;
205 	}
206 	if (*s == '#') {
207 		**line = '\0';
208 		*linesize = 0;
209 		return (freeme);
210 	}
211 	memmove(*line, s, *linesize - (s - *line));
212 	*linesize -= s - *line;
213 	for (s = &(*line)[*linesize - 1]; s >= *line; s--) {
214 		if (!isspace(*s))
215 			break;
216 	}
217 	if (s != &(*line)[*linesize - 1]) {
218 		*linesize = s - *line + 1;
219 	} else {
220 		s = malloc(*linesize + 1);
221 		if (s == NULL)
222 			err(1, "malloc");
223 		strncpy(s, *line, *linesize);
224 		*line = s;
225 		freeme = 1;
226 	}
227 	(*line)[*linesize] = '\0';
228 	return (freeme);
229 }
230 
231 void
232 add_specs(struct label_specs *specs, const char *file, int is_sebsd)
233 {
234 	struct label_spec *spec;
235 	FILE *fp;
236 	char *line;
237 	size_t nlines = 0, linesize;
238 	int freeline;
239 
240 	spec = malloc(sizeof(*spec));
241 	if (spec == NULL)
242 		err(1, "malloc");
243 	fp = fopen(file, "r");
244 	if (fp == NULL)
245 		err(1, "opening %s", file);
246 	while ((line = fgetln(fp, &linesize)) != NULL) {
247 		freeline = chomp_line(&line, &linesize);
248 		if (linesize > 0) /* only allocate space for non-comments */
249 			nlines++;
250 		if (freeline)
251 			free(line);
252 	}
253 	if (ferror(fp))
254 		err(1, "fgetln on %s", file);
255 	rewind(fp);
256 	spec->entries = calloc(nlines, sizeof(*spec->entries));
257 	if (spec->entries == NULL)
258 		err(1, "malloc");
259 	spec->nentries = nlines;
260 	while (nlines > 0) {
261 		line = fgetln(fp, &linesize);
262 		if (line == NULL) {
263 			if (feof(fp))
264 				errx(1, "%s ended prematurely", file);
265 			else
266 				err(1, "failure reading %s", file);
267 		}
268 		freeline = chomp_line(&line, &linesize);
269 		if (linesize == 0) {
270 			if (freeline)
271 				free(line);
272 			continue;
273 		}
274 		add_spec_line(file, is_sebsd, &spec->entries[--nlines], line);
275 		if (freeline)
276 			free(line);
277 	}
278 	fclose(fp);
279 	if (!qflag)
280 		warnx("%s: read %lu specifications", file,
281 		    (long)spec->nentries);
282 	STAILQ_INSERT_TAIL(&specs->head, spec, link);
283 }
284 
285 void
286 add_setfmac_specs(struct label_specs *specs, char *label)
287 {
288 	struct label_spec *spec;
289 
290 	spec = malloc(sizeof(*spec));
291 	if (spec == NULL)
292 		err(1, "malloc");
293 	spec->nentries = 1;
294 	spec->entries = calloc(spec->nentries, sizeof(*spec->entries));
295 	if (spec->entries == NULL)
296 		err(1, "malloc");
297 	/* The _only_ thing specified here is the mactext! */
298 	spec->entries->mactext = label;
299 	spec->entries->flags |= F_ALWAYSMATCH;
300 	STAILQ_INSERT_TAIL(&specs->head, spec, link);
301 }
302 
303 void
304 add_spec_line(const char *file, int is_sebsd, struct label_spec_entry *entry,
305     char *line)
306 {
307 	char *regexstr, *modestr, *macstr, *regerrorstr;
308 	size_t size;
309 	int error;
310 
311 	regexstr = strtok(line, " \t");
312 	if (regexstr == NULL)
313 		errx(1, "%s: need regular expression", file);
314 	modestr = strtok(NULL, " \t");
315 	if (modestr == NULL)
316 		errx(1, "%s: need a label", file);
317 	macstr = strtok(NULL, " \t");
318 	if (macstr == NULL) {	/* the mode is just optional */
319 		macstr = modestr;
320 		modestr = NULL;
321 	}
322 	if (strtok(NULL, " \t") != NULL)
323 		errx(1, "%s: extraneous fields at end of line", file);
324 	/* assume we need to anchor this regex */
325 	if (asprintf(&regexstr, "^%s$", regexstr) == -1)
326 		err(1, "%s: processing regular expression", file);
327 	entry->regexstr = regexstr;
328 	error = regcomp(&entry->regex, regexstr, REG_EXTENDED | REG_NOSUB);
329 	if (error) {
330 		size = regerror(error, &entry->regex, NULL, 0);
331 		regerrorstr = malloc(size);
332 		if (regerrorstr == NULL)
333 			err(1, "malloc");
334 		(void)regerror(error, &entry->regex, regerrorstr, size);
335 		errx(1, "%s: %s: %s", file, entry->regexstr, regerrorstr);
336 	}
337 	if (!is_sebsd) {
338 		entry->mactext = strdup(macstr);
339 		if (entry->mactext == NULL)
340 			err(1, "strdup");
341 	} else {
342 		if (asprintf(&entry->mactext, "sebsd/%s", macstr) == -1)
343 			err(1, "asprintf");
344 		if (strcmp(macstr, "<<none>>") == 0)
345 			entry->flags |= F_DONTLABEL;
346 	}
347 	if (modestr != NULL) {
348 		if (strlen(modestr) != 2 || modestr[0] != '-')
349 			errx(1, "%s: invalid mode string: %s", file, modestr);
350 		switch (modestr[1]) {
351 		case 'b':
352 			entry->mode = S_IFBLK;
353 			entry->modestr = ",-b";
354 			break;
355 		case 'c':
356 			entry->mode = S_IFCHR;
357 			entry->modestr = ",-c";
358 			break;
359 		case 'd':
360 			entry->mode = S_IFDIR;
361 			entry->modestr = ",-d";
362 			break;
363 		case 'p':
364 			entry->mode = S_IFIFO;
365 			entry->modestr = ",-p";
366 			break;
367 		case 'l':
368 			entry->mode = S_IFLNK;
369 			entry->modestr = ",-l";
370 			break;
371 		case 's':
372 			entry->mode = S_IFSOCK;
373 			entry->modestr = ",-s";
374 			break;
375 		case '-':
376 			entry->mode = S_IFREG;
377 			entry->modestr = ",--";
378 			break;
379 		default:
380 			errx(1, "%s: invalid mode string: %s", file, modestr);
381 		}
382 	} else {
383 		entry->modestr = "";
384 	}
385 }
386 
387 int
388 specs_empty(struct label_specs *specs)
389 {
390 
391 	return (STAILQ_EMPTY(&specs->head));
392 }
393 
394 int
395 apply_specs(struct label_specs *specs, FTSENT *ftsent, int hflag, int vflag)
396 {
397 	regmatch_t pmatch;
398 	struct label_spec *ls;
399 	struct label_spec_entry *ent;
400 	char *regerrorstr, *macstr;
401 	size_t size;
402 	mac_t mac;
403 	int error, matchedby;
404 
405 	/*
406 	 * Work through file context sources in order of specification
407 	 * on the command line, and through their entries in reverse
408 	 * order to find the "last" (hopefully "best") match.
409 	 */
410 	matchedby = 0;
411 	STAILQ_FOREACH(ls, &specs->head, link) {
412 		for (ls->match = NULL, ent = ls->entries;
413 		    ent < &ls->entries[ls->nentries]; ent++) {
414 			if (ent->flags & F_ALWAYSMATCH)
415 				goto matched;
416 			if (ent->mode != 0 &&
417 			    (ftsent->fts_statp->st_mode & S_IFMT) != ent->mode)
418 				continue;
419 			pmatch.rm_so = 0;
420 			pmatch.rm_eo = ftsent->fts_pathlen;
421 			error = regexec(&ent->regex, ftsent->fts_path, 1,
422 			    &pmatch, REG_STARTEND);
423 			switch (error) {
424 			case REG_NOMATCH:
425 				continue;
426 			case 0:
427 				break;
428 			default:
429 				size = regerror(error, &ent->regex, NULL, 0);
430 				regerrorstr = malloc(size);
431 				if (regerrorstr == NULL)
432 					err(1, "malloc");
433 				(void)regerror(error, &ent->regex, regerrorstr,
434 				    size);
435 				errx(1, "%s: %s", ent->regexstr, regerrorstr);
436 			}
437 		matched:
438 			ls->match = ent;
439 			if (vflag) {
440 				if (matchedby == 0) {
441 					printf("%s matched by ",
442 					    ftsent->fts_path);
443 					matchedby = 1;
444 				}
445 				printf("%s(%s%s,%s)", matchedby == 2 ? "," : "",
446 				    ent->regexstr, ent->modestr, ent->mactext);
447 				if (matchedby == 1)
448 					matchedby = 2;
449 			}
450 			break;
451 		}
452 	}
453 	if (vflag && matchedby)
454 		printf("\n");
455 	size = 0;
456 	STAILQ_FOREACH(ls, &specs->head, link) {
457 		/* cached match decision */
458 		if (ls->match && (ls->match->flags & F_DONTLABEL) == 0)
459 			 /* add length of "x\0"/"y," */
460 			size += strlen(ls->match->mactext) + 1;
461 	}
462 	if (size == 0)
463 		return (0);
464 	macstr = malloc(size);
465 	if (macstr == NULL)
466 		err(1, "malloc");
467 	*macstr = '\0';
468 	STAILQ_FOREACH(ls, &specs->head, link) {
469 		/* cached match decision */
470 		if (ls->match && (ls->match->flags & F_DONTLABEL) == 0) {
471 			if (*macstr != '\0')
472 				strcat(macstr, ",");
473 			strcat(macstr, ls->match->mactext);
474 		}
475 	}
476 	if (mac_from_text(&mac, macstr))
477 		err(1, "mac_from_text(%s)", macstr);
478 	if ((hflag == FTS_PHYSICAL ? mac_set_link(ftsent->fts_accpath, mac) :
479 	    mac_set_file(ftsent->fts_accpath, mac)) != 0) {
480 		if (errno == EOPNOTSUPP) {
481 			mac_free(mac);
482 			free(macstr);
483 			return (1);
484 		}
485 		err(1, "mac_set_link(%s, %s)", ftsent->fts_path, macstr);
486 	}
487 	mac_free(mac);
488 	free(macstr);
489 	return (0);
490 }
491 
492 struct label_specs *
493 new_specs(void)
494 {
495 	struct label_specs *specs;
496 
497 	specs = malloc(sizeof(*specs));
498 	if (specs == NULL)
499 		err(1, "malloc");
500 	STAILQ_INIT(&specs->head);
501 	return (specs);
502 }
503