1 /* $NetBSD: rm.c,v 1.53 2013/04/26 18:43:22 christos Exp $ */
2
3 /*-
4 * Copyright (c) 1990, 1993, 1994, 2003
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 #include <sys/cdefs.h>
33 #ifndef lint
34 __COPYRIGHT("@(#) Copyright (c) 1990, 1993, 1994\
35 The Regents of the University of California. All rights reserved.");
36 #endif /* not lint */
37
38 #ifndef lint
39 #if 0
40 static char sccsid[] = "@(#)rm.c 8.8 (Berkeley) 4/27/95";
41 #else
42 __RCSID("$NetBSD: rm.c,v 1.53 2013/04/26 18:43:22 christos Exp $");
43 #endif
44 #endif /* not lint */
45
46 #include <sys/param.h>
47 #include <sys/stat.h>
48 #include <sys/types.h>
49
50 #include <err.h>
51 #include <errno.h>
52 #include <fcntl.h>
53 #include <fts.h>
54 #include <grp.h>
55 #include <locale.h>
56 #include <pwd.h>
57 #include <signal.h>
58 #include <stdio.h>
59 #include <stdlib.h>
60 #include <string.h>
61 #include <unistd.h>
62
63 static int dflag, eval, fflag, iflag, Pflag, stdin_ok, vflag, Wflag;
64 static int xflag;
65 static sig_atomic_t pinfo;
66
67 static int check(char *, char *, struct stat *);
68 static void checkdot(char **);
69 static void progress(int);
70 static void rm_file(char **);
71 static int rm_overwrite(char *, struct stat *);
72 static void rm_tree(char **);
73 __dead static void usage(void);
74
75 /*
76 * For the sake of the `-f' flag, check whether an error number indicates the
77 * failure of an operation due to an non-existent file, either per se (ENOENT)
78 * or because its filename argument was illegal (ENAMETOOLONG, ENOTDIR).
79 */
80 #define NONEXISTENT(x) \
81 ((x) == ENOENT || (x) == ENAMETOOLONG || (x) == ENOTDIR)
82
83 /*
84 * rm --
85 * This rm is different from historic rm's, but is expected to match
86 * POSIX 1003.2 behavior. The most visible difference is that -f
87 * has two specific effects now, ignore non-existent files and force
88 * file removal.
89 */
90 int
main(int argc,char * argv[])91 main(int argc, char *argv[])
92 {
93 int ch, rflag;
94
95 setprogname(argv[0]);
96 (void)setlocale(LC_ALL, "");
97
98 Pflag = rflag = xflag = 0;
99 while ((ch = getopt(argc, argv, "dfiPRrvWx")) != -1)
100 switch (ch) {
101 case 'd':
102 dflag = 1;
103 break;
104 case 'f':
105 fflag = 1;
106 iflag = 0;
107 break;
108 case 'i':
109 fflag = 0;
110 iflag = 1;
111 break;
112 case 'P':
113 Pflag = 1;
114 break;
115 case 'R':
116 case 'r': /* Compatibility. */
117 rflag = 1;
118 break;
119 case 'v':
120 vflag = 1;
121 break;
122 case 'x':
123 xflag = 1;
124 break;
125 #ifndef __ANDROID__
126 case 'W':
127 Wflag = 1;
128 break;
129 #endif
130 case '?':
131 default:
132 usage();
133 }
134 argc -= optind;
135 argv += optind;
136
137 if (argc < 1) {
138 if (fflag)
139 return 0;
140 usage();
141 }
142
143 (void)signal(SIGINFO, progress);
144
145 checkdot(argv);
146
147 if (*argv) {
148 stdin_ok = isatty(STDIN_FILENO);
149
150 if (rflag)
151 rm_tree(argv);
152 else
153 rm_file(argv);
154 }
155
156 exit(eval);
157 /* NOTREACHED */
158 }
159
160 static void
rm_tree(char ** argv)161 rm_tree(char **argv)
162 {
163 FTS *fts;
164 FTSENT *p;
165 int flags, needstat, rval;
166
167 /*
168 * Remove a file hierarchy. If forcing removal (-f), or interactive
169 * (-i) or can't ask anyway (stdin_ok), don't stat the file.
170 */
171 needstat = !fflag && !iflag && stdin_ok;
172
173 /*
174 * If the -i option is specified, the user can skip on the pre-order
175 * visit. The fts_number field flags skipped directories.
176 */
177 #define SKIPPED 1
178
179 flags = FTS_PHYSICAL;
180 if (!needstat)
181 flags |= FTS_NOSTAT;
182 #ifndef __ANDROID__
183 if (Wflag)
184 flags |= FTS_WHITEOUT;
185 #endif
186 if (xflag)
187 flags |= FTS_XDEV;
188 if ((fts = fts_open(argv, flags, NULL)) == NULL)
189 err(1, "fts_open failed");
190 while ((p = fts_read(fts)) != NULL) {
191
192 switch (p->fts_info) {
193 case FTS_DNR:
194 if (!fflag || p->fts_errno != ENOENT) {
195 warnx("%s: %s", p->fts_path,
196 strerror(p->fts_errno));
197 eval = 1;
198 }
199 continue;
200 case FTS_ERR:
201 errx(EXIT_FAILURE, "%s: %s", p->fts_path,
202 strerror(p->fts_errno));
203 /* NOTREACHED */
204 case FTS_NS:
205 /*
206 * FTS_NS: assume that if can't stat the file, it
207 * can't be unlinked.
208 */
209 if (fflag && NONEXISTENT(p->fts_errno))
210 continue;
211 if (needstat) {
212 warnx("%s: %s", p->fts_path,
213 strerror(p->fts_errno));
214 eval = 1;
215 continue;
216 }
217 break;
218 case FTS_D:
219 /* Pre-order: give user chance to skip. */
220 if (!fflag && !check(p->fts_path, p->fts_accpath,
221 p->fts_statp)) {
222 (void)fts_set(fts, p, FTS_SKIP);
223 p->fts_number = SKIPPED;
224 }
225 continue;
226 case FTS_DP:
227 /* Post-order: see if user skipped. */
228 if (p->fts_number == SKIPPED)
229 continue;
230 break;
231 default:
232 if (!fflag &&
233 !check(p->fts_path, p->fts_accpath, p->fts_statp))
234 continue;
235 }
236
237 rval = 0;
238 /*
239 * If we can't read or search the directory, may still be
240 * able to remove it. Don't print out the un{read,search}able
241 * message unless the remove fails.
242 */
243 switch (p->fts_info) {
244 case FTS_DP:
245 case FTS_DNR:
246 rval = rmdir(p->fts_accpath);
247 if (rval != 0 && fflag && errno == ENOENT)
248 continue;
249 break;
250
251 #ifndef __ANDROID__
252 case FTS_W:
253 rval = undelete(p->fts_accpath);
254 if (rval != 0 && fflag && errno == ENOENT)
255 continue;
256 break;
257 #endif
258
259 default:
260 if (Pflag) {
261 if (rm_overwrite(p->fts_accpath, NULL))
262 continue;
263 }
264 rval = unlink(p->fts_accpath);
265 if (rval != 0 && fflag && NONEXISTENT(errno))
266 continue;
267 break;
268 }
269 if (rval != 0) {
270 warn("%s", p->fts_path);
271 eval = 1;
272 } else if (vflag || pinfo) {
273 pinfo = 0;
274 (void)printf("%s\n", p->fts_path);
275 }
276 }
277 if (errno)
278 err(1, "fts_read");
279 fts_close(fts);
280 }
281
282 static void
rm_file(char ** argv)283 rm_file(char **argv)
284 {
285 struct stat sb;
286 int rval;
287 char *f;
288
289 /*
290 * Remove a file. POSIX 1003.2 states that, by default, attempting
291 * to remove a directory is an error, so must always stat the file.
292 */
293 while ((f = *argv++) != NULL) {
294 /* Assume if can't stat the file, can't unlink it. */
295 if (lstat(f, &sb)) {
296 #ifndef __ANDROID__
297 if (Wflag) {
298 sb.st_mode = S_IFWHT|S_IWUSR|S_IRUSR;
299 } else {
300 #endif
301 if (!fflag || !NONEXISTENT(errno)) {
302 warn("%s", f);
303 eval = 1;
304 }
305 continue;
306 #ifndef __ANDROID__
307 }
308 } else if (Wflag) {
309 warnx("%s: %s", f, strerror(EEXIST));
310 eval = 1;
311 continue;
312 #endif
313 }
314
315 if (S_ISDIR(sb.st_mode) && !dflag) {
316 warnx("%s: is a directory", f);
317 eval = 1;
318 continue;
319 }
320 if (!fflag && !S_ISWHT(sb.st_mode) && !check(f, f, &sb))
321 continue;
322 #ifndef __ANDROID__
323 if (S_ISWHT(sb.st_mode))
324 rval = undelete(f);
325 else if (S_ISDIR(sb.st_mode))
326 #else
327 if (S_ISDIR(sb.st_mode))
328 #endif
329 rval = rmdir(f);
330 else {
331 if (Pflag) {
332 if (rm_overwrite(f, &sb))
333 continue;
334 }
335 rval = unlink(f);
336 }
337 if (rval && (!fflag || !NONEXISTENT(errno))) {
338 warn("%s", f);
339 eval = 1;
340 }
341 if (vflag && rval == 0)
342 (void)printf("%s\n", f);
343 }
344 }
345
346 /*
347 * rm_overwrite --
348 * Overwrite the file 3 times with varying bit patterns.
349 *
350 * This is an expensive way to keep people from recovering files from your
351 * non-snapshotted FFS filesystems using fsdb(8). Really. No more. Only
352 * regular files are deleted, directories (and therefore names) will remain.
353 * Also, this assumes a fixed-block file system (like FFS, or a V7 or a
354 * System V file system). In a logging file system, you'll have to have
355 * kernel support.
356 *
357 * A note on standards: U.S. DoD 5220.22-M "National Industrial Security
358 * Program Operating Manual" ("NISPOM") is often cited as a reference
359 * for clearing and sanitizing magnetic media. In fact, a matrix of
360 * "clearing" and "sanitization" methods for various media was given in
361 * Chapter 8 of the original 1995 version of NISPOM. However, that
362 * matrix was *removed from the document* when Chapter 8 was rewritten
363 * in Change 2 to the document in 2001. Recently, the Defense Security
364 * Service has made a revised clearing and sanitization matrix available
365 * in Microsoft Word format on the DSS web site. The standardization
366 * status of this matrix is unclear. Furthermore, one must be very
367 * careful when referring to this matrix: it is intended for the "clearing"
368 * prior to reuse or "sanitization" prior to disposal of *entire media*,
369 * not individual files and the only non-physically-destructive method of
370 * "sanitization" that is permitted for magnetic disks of any kind is
371 * specifically noted to be prohibited for media that have contained
372 * Top Secret data.
373 *
374 * It is impossible to actually conform to the exact procedure given in
375 * the matrix if one is overwriting a file, not an entire disk, because
376 * the procedure requires examination and comparison of the disk's defect
377 * lists. Any program that claims to securely erase *files* while
378 * conforming to the standard, then, is not correct. We do as much of
379 * what the standard requires as can actually be done when erasing a
380 * file, rather than an entire disk; but that does not make us conformant.
381 *
382 * Furthermore, the presence of track caches, disk and controller write
383 * caches, and so forth make it extremely difficult to ensure that data
384 * have actually been written to the disk, particularly when one tries
385 * to repeatedly overwrite the same sectors in quick succession. We call
386 * fsync(), but controllers with nonvolatile cache, as well as IDE disks
387 * that just plain lie about the stable storage of data, will defeat this.
388 *
389 * Finally, widely respected research suggests that the given procedure
390 * is nowhere near sufficient to prevent the recovery of data using special
391 * forensic equipment and techniques that are well-known. This is
392 * presumably one reason that the matrix requires physical media destruction,
393 * rather than any technique of the sort attempted here, for secret data.
394 *
395 * Caveat Emptor.
396 *
397 * rm_overwrite will return 0 on success.
398 */
399
400 static int
rm_overwrite(char * file,struct stat * sbp)401 rm_overwrite(char *file, struct stat *sbp)
402 {
403 struct stat sb, sb2;
404 int fd, randint;
405 char randchar;
406
407 fd = -1;
408 if (sbp == NULL) {
409 if (lstat(file, &sb))
410 goto err;
411 sbp = &sb;
412 }
413 if (!S_ISREG(sbp->st_mode))
414 return 0;
415
416 /* flags to try to defeat hidden caching by forcing seeks */
417 if ((fd = open(file, O_RDWR|O_SYNC|O_RSYNC|O_NOFOLLOW, 0)) == -1)
418 goto err;
419
420 if (fstat(fd, &sb2)) {
421 goto err;
422 }
423
424 if (sb2.st_dev != sbp->st_dev || sb2.st_ino != sbp->st_ino ||
425 !S_ISREG(sb2.st_mode)) {
426 errno = EPERM;
427 goto err;
428 }
429
430 #define RAND_BYTES 1
431 #define THIS_BYTE 0
432
433 #define WRITE_PASS(mode, byte) do { \
434 off_t len; \
435 size_t wlen, i; \
436 char buf[8 * 1024]; \
437 \
438 if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET)) \
439 goto err; \
440 \
441 if (mode == THIS_BYTE) \
442 memset(buf, byte, sizeof(buf)); \
443 for (len = sbp->st_size; len > 0; len -= wlen) { \
444 if (mode == RAND_BYTES) { \
445 for (i = 0; i < sizeof(buf); \
446 i+= sizeof(u_int32_t)) \
447 *(int *)(buf + i) = arc4random(); \
448 } \
449 wlen = len < (off_t)sizeof(buf) ? (size_t)len : sizeof(buf); \
450 if ((size_t)write(fd, buf, wlen) != wlen) \
451 goto err; \
452 } \
453 sync(); /* another poke at hidden caches */ \
454 } while (/* CONSTCOND */ 0)
455
456 #define READ_PASS(byte) do { \
457 off_t len; \
458 size_t rlen; \
459 char pattern[8 * 1024]; \
460 char buf[8 * 1024]; \
461 \
462 if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET)) \
463 goto err; \
464 \
465 memset(pattern, byte, sizeof(pattern)); \
466 for(len = sbp->st_size; len > 0; len -= rlen) { \
467 rlen = len < (off_t)sizeof(buf) ? (size_t)len : sizeof(buf); \
468 if((size_t)read(fd, buf, rlen) != rlen) \
469 goto err; \
470 if(memcmp(buf, pattern, rlen)) \
471 goto err; \
472 } \
473 sync(); /* another poke at hidden caches */ \
474 } while (/* CONSTCOND */ 0)
475
476 /*
477 * DSS sanitization matrix "clear" for magnetic disks:
478 * option 'c' "Overwrite all addressable locations with a single
479 * character."
480 */
481 randint = arc4random();
482 randchar = *(char *)&randint;
483 WRITE_PASS(THIS_BYTE, randchar);
484
485 /*
486 * DSS sanitization matrix "sanitize" for magnetic disks:
487 * option 'd', sub 2 "Overwrite all addressable locations with a
488 * character, then its complement. Verify "complement" character
489 * was written successfully to all addressable locations, then
490 * overwrite all addressable locations with random characters; or
491 * verify third overwrite of random characters." The rest of the
492 * text in d-sub-2 specifies requirements for overwriting spared
493 * sectors; we cannot conform to it when erasing only a file, thus
494 * we do not conform to the standard.
495 */
496
497 /* 1. "a character" */
498 WRITE_PASS(THIS_BYTE, 0xff);
499
500 /* 2. "its complement" */
501 WRITE_PASS(THIS_BYTE, 0x00);
502
503 /* 3. "Verify 'complement' character" */
504 READ_PASS(0x00);
505
506 /* 4. "overwrite all addressable locations with random characters" */
507
508 WRITE_PASS(RAND_BYTES, 0x00);
509
510 /*
511 * As the file might be huge, and we note that this revision of
512 * the matrix says "random characters", not "a random character"
513 * as the original did, we do not verify the random-character
514 * write; the "or" in the standard allows this.
515 */
516
517 if (close(fd) == -1) {
518 fd = -1;
519 goto err;
520 }
521
522 return 0;
523
524 err: eval = 1;
525 warn("%s", file);
526 if (fd != -1)
527 close(fd);
528 return 1;
529 }
530
531 static int
check(char * path,char * name,struct stat * sp)532 check(char *path, char *name, struct stat *sp)
533 {
534 int ch, first;
535 char modep[15];
536
537 /* Check -i first. */
538 if (iflag)
539 (void)fprintf(stderr, "remove '%s'? ", path);
540 else {
541 /*
542 * If it's not a symbolic link and it's unwritable and we're
543 * talking to a terminal, ask. Symbolic links are excluded
544 * because their permissions are meaningless. Check stdin_ok
545 * first because we may not have stat'ed the file.
546 */
547 if (!stdin_ok || S_ISLNK(sp->st_mode) ||
548 !(access(name, W_OK) && (errno != ETXTBSY)))
549 return (1);
550 strmode(sp->st_mode, modep);
551 if (Pflag) {
552 warnx(
553 "%s: -P was specified but file could not"
554 " be overwritten", path);
555 return 0;
556 }
557 (void)fprintf(stderr, "override %s%s%s:%s for '%s'? ",
558 modep + 1, modep[9] == ' ' ? "" : " ",
559 user_from_uid(sp->st_uid, 0),
560 group_from_gid(sp->st_gid, 0), path);
561 }
562 (void)fflush(stderr);
563
564 first = ch = getchar();
565 while (ch != '\n' && ch != EOF)
566 ch = getchar();
567 return (first == 'y' || first == 'Y');
568 }
569
570 /*
571 * POSIX.2 requires that if "." or ".." are specified as the basename
572 * portion of an operand, a diagnostic message be written to standard
573 * error and nothing more be done with such operands.
574 *
575 * Since POSIX.2 defines basename as the final portion of a path after
576 * trailing slashes have been removed, we'll remove them here.
577 */
578 #define ISDOT(a) ((a)[0] == '.' && (!(a)[1] || ((a)[1] == '.' && !(a)[2])))
579 static void
checkdot(char ** argv)580 checkdot(char **argv)
581 {
582 char *p, **save, **t;
583 int complained;
584
585 complained = 0;
586 for (t = argv; *t;) {
587 /* strip trailing slashes */
588 p = strrchr(*t, '\0');
589 while (--p > *t && *p == '/')
590 *p = '\0';
591
592 /* extract basename */
593 if ((p = strrchr(*t, '/')) != NULL)
594 ++p;
595 else
596 p = *t;
597
598 if (ISDOT(p)) {
599 if (!complained++)
600 warnx("\".\" and \"..\" may not be removed");
601 eval = 1;
602 for (save = t; (t[0] = t[1]) != NULL; ++t)
603 continue;
604 t = save;
605 } else
606 ++t;
607 }
608 }
609
610 static void
usage(void)611 usage(void)
612 {
613
614 (void)fprintf(stderr, "usage: %s [-f|-i] [-dPRrvWx] file ...\n",
615 getprogname());
616 exit(1);
617 /* NOTREACHED */
618 }
619
620 static void
progress(int sig __unused)621 progress(int sig __unused)
622 {
623
624 pinfo++;
625 }
626