/* $NetBSD: rm.c,v 1.58 2026/04/26 01:49:28 jschauma Exp $ */ /*- * Copyright (c) 1990, 1993, 1994, 2003 * The Regents of the University of California. 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. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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. */ #include <sys/cdefs.h> #ifndef lint __COPYRIGHT("@(#) Copyright (c) 1990, 1993, 1994\ The Regents of the University of California. All rights reserved."); #endif /* not lint */ #ifndef lint #if 0 static char sccsid[] = "@(#)rm.c 8.8 (Berkeley) 4/27/95"; #else __RCSID("$NetBSD: rm.c,v 1.58 2026/04/26 01:49:28 jschauma Exp $"); #endif #endif /* not lint */ #include <sys/param.h> #include <sys/stat.h> #include <sys/types.h> #include <err.h> #include <errno.h> #include <fcntl.h> #include <fts.h> #include <grp.h> #include <locale.h> #include <pwd.h> #include <signal.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> static int dflag, eval, fflag, iflag, Pflag, stdin_ok, vflag, Wflag; static int xflag; static sig_atomic_t pinfo; static int check(char *, char *, struct stat *, const char *); static void checkdot(char **); static void progress(int); static void rm_file(char **); static int rm_overwrite(char *, struct stat *); static void rm_tree(char **); __dead static void usage(void); /* * For the sake of the `-f' flag, check whether an error number indicates the * failure of an operation due to an non-existent file, either per se (ENOENT) * or because its filename argument was illegal (ENAMETOOLONG, ENOTDIR). */ #define NONEXISTENT(x) \ ((x) == ENOENT || (x) == ENAMETOOLONG || (x) == ENOTDIR) /* * rm -- * This rm is different from historic rm's, but is expected to match * POSIX 1003.2 behavior. The most visible difference is that -f * has two specific effects now, ignore non-existent files and force * file removal. */ int main(int argc, char *argv[]) { int ch, rflag; setprogname(argv[0]); (void)setlocale(LC_ALL, ""); rflag = 0; while ((ch = getopt(argc, argv, "dfiPRrvWx")) != -1) switch (ch) { case 'd': dflag = 1; break; case 'f': fflag = 1; iflag = 0; break; case 'i': fflag = 0; iflag = 1; break; case 'P': Pflag = 1; break; case 'R': case 'r': /* Compatibility. */ rflag = 1; break; case 'v': vflag = 1; break; case 'x': xflag = 1; break; case 'W': Wflag = 1; break; case '?': default: usage(); } argc -= optind; argv += optind; if (argc < 1) { if (fflag) return 0; usage(); } (void)signal(SIGINFO, progress); checkdot(argv); if (*argv) { stdin_ok = isatty(STDIN_FILENO); if (rflag) rm_tree(argv); else rm_file(argv); } exit(eval); /* NOTREACHED */ } static void rm_tree(char **argv) { FTS *fts; FTSENT *p; int flags, needstat, rval; /* * Remove a file hierarchy. If forcing removal (-f), or interactive * (-i) or can't ask anyway (stdin_ok), don't stat the file. */ needstat = !fflag && !iflag && stdin_ok; /* * If the -i option is specified, the user can skip on the pre-order * visit. The fts_number field flags skipped directories. */ #define SKIPPED 1 flags = FTS_PHYSICAL; if (!needstat) flags |= FTS_NOSTAT; if (Wflag) flags |= FTS_WHITEOUT; if (xflag) flags |= FTS_XDEV; if ((fts = fts_open(argv, flags, NULL)) == NULL) err(1, "fts_open failed"); while ((p = fts_read(fts)) != NULL) { switch (p->fts_info) { case FTS_DNR: if (!fflag || p->fts_errno != ENOENT) { warnx("%s: %s", p->fts_path, strerror(p->fts_errno)); eval = 1; } continue; case FTS_ERR: errx(EXIT_FAILURE, "%s: %s", p->fts_path, strerror(p->fts_errno)); /* NOTREACHED */ case FTS_NS: /* * FTS_NS: assume that if can't stat the file, it * can't be unlinked. */ if (fflag && NONEXISTENT(p->fts_errno)) continue; if (needstat) { warnx("%s: %s", p->fts_path, strerror(p->fts_errno)); eval = 1; continue; } break; case FTS_D: /* Pre-order: give user chance to skip. */ if (!fflag && !check(p->fts_path, p->fts_accpath, p->fts_statp, "examine files in")) { (void)fts_set(fts, p, FTS_SKIP); p->fts_number = SKIPPED; } continue; case FTS_DP: /* Post-order: see if user skipped. */ if (p->fts_number == SKIPPED) continue; break; default: if (!fflag && !check(p->fts_path, p->fts_accpath, p->fts_statp, "remove")) continue; } rval = 0; /* * If we can't read or search the directory, may still be * able to remove it. Don't print out the un{read,search}able * message unless the remove fails. */ switch (p->fts_info) { case FTS_DP: case FTS_DNR: if (!fflag && !check(p->fts_path, p->fts_accpath, p->fts_statp, "remove")) continue; rval = rmdir(p->fts_accpath); if (rval != 0 && fflag && errno == ENOENT) continue; break; case FTS_W: rval = undelete(p->fts_accpath); if (rval != 0 && fflag && errno == ENOENT) continue; break; default: if (Pflag) { if (rm_overwrite(p->fts_accpath, NULL)) continue; } rval = unlink(p->fts_accpath); if (rval != 0 && fflag && NONEXISTENT(errno)) continue; break; } if (rval != 0) { warn("%s", p->fts_path); eval = 1; } else if (vflag || pinfo) { pinfo = 0; (void)printf("%s\n", p->fts_path); } } if (errno) err(1, "fts_read"); fts_close(fts); } static void rm_file(char **argv) { struct stat sb; int rval; char *f; /* * Remove a file. POSIX 1003.2 states that, by default, attempting * to remove a directory is an error, so must always stat the file. */ while ((f = *argv++) != NULL) { /* Assume if can't stat the file, can't unlink it. */ if (lstat(f, &sb)) { if (Wflag) { sb.st_mode = S_IFWHT|S_IWUSR|S_IRUSR; } else { if (!fflag || !NONEXISTENT(errno)) { warn("%s", f); eval = 1; } continue; } } else if (Wflag) { warnx("%s: %s", f, strerror(EEXIST)); eval = 1; continue; } if (S_ISDIR(sb.st_mode) && !dflag) { warnx("%s: is a directory", f); eval = 1; continue; } if (!fflag && !S_ISWHT(sb.st_mode) && !check(f, f, &sb, "remove")) continue; if (S_ISWHT(sb.st_mode)) rval = undelete(f); else if (S_ISDIR(sb.st_mode)) rval = rmdir(f); else { if (Pflag) { if (rm_overwrite(f, &sb)) continue; } rval = unlink(f); } if (rval && (!fflag || !NONEXISTENT(errno))) { warn("%s", f); eval = 1; } if (vflag && rval == 0) (void)printf("%s\n", f); } } /* * rm_overwrite -- * Overwrite the file 3 times with varying bit patterns. * * This is an expensive way to keep people from recovering files from your * non-snapshotted FFS filesystems using fsdb(8). Really. No more. Only * regular files are deleted, directories (and therefore names) will remain. * Also, this assumes a fixed-block file system (like FFS, or a V7 or a * System V file system). In a logging file system, you'll have to have * kernel support. * * A note on standards: U.S. DoD 5220.22-M "National Industrial Security * Program Operating Manual" ("NISPOM") is often cited as a reference * for clearing and sanitizing magnetic media. In fact, a matrix of * "clearing" and "sanitization" methods for various media was given in * Chapter 8 of the original 1995 version of NISPOM. However, that * matrix was *removed from the document* when Chapter 8 was rewritten * in Change 2 to the document in 2001. Recently, the Defense Security * Service has made a revised clearing and sanitization matrix available * in Microsoft Word format on the DSS web site. The standardization * status of this matrix is unclear. Furthermore, one must be very * careful when referring to this matrix: it is intended for the "clearing" * prior to reuse or "sanitization" prior to disposal of *entire media*, * not individual files and the only non-physically-destructive method of * "sanitization" that is permitted for magnetic disks of any kind is * specifically noted to be prohibited for media that have contained * Top Secret data. * * It is impossible to actually conform to the exact procedure given in * the matrix if one is overwriting a file, not an entire disk, because * the procedure requires examination and comparison of the disk's defect * lists. Any program that claims to securely erase *files* while * conforming to the standard, then, is not correct. We do as much of * what the standard requires as can actually be done when erasing a * file, rather than an entire disk; but that does not make us conformant. * * Furthermore, the presence of track caches, disk and controller write * caches, and so forth make it extremely difficult to ensure that data * have actually been written to the disk, particularly when one tries * to repeatedly overwrite the same sectors in quick succession. We call * fsync(), but controllers with nonvolatile cache, as well as IDE disks * that just plain lie about the stable storage of data, will defeat this. * * Finally, widely respected research suggests that the given procedure * is nowhere near sufficient to prevent the recovery of data using special * forensic equipment and techniques that are well-known. This is * presumably one reason that the matrix requires physical media destruction, * rather than any technique of the sort attempted here, for secret data. * * Caveat Emptor. * * rm_overwrite will return 0 on success. */ static int rm_overwrite(char *file, struct stat *sbp) { struct stat sb, sb2; int fd, randint; char randchar; fd = -1; if (sbp == NULL) { if (lstat(file, &sb)) goto err; sbp = &sb; } if (!S_ISREG(sbp->st_mode)) return 0; /* flags to try to defeat hidden caching by forcing seeks */ if ((fd = open(file, O_RDWR|O_SYNC|O_RSYNC|O_NOFOLLOW, 0)) == -1) goto err; if (fstat(fd, &sb2)) { goto err; } if (sb2.st_dev != sbp->st_dev || sb2.st_ino != sbp->st_ino || !S_ISREG(sb2.st_mode)) { errno = EPERM; goto err; } #define RAND_BYTES 1 #define THIS_BYTE 0 #define WRITE_PASS(mode, byte) do { \ off_t len; \ size_t wlen, i; \ char buf[8 * 1024]; \ \ if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET)) \ goto err; \ \ if (mode == THIS_BYTE) \ memset(buf, byte, sizeof(buf)); \ for (len = sbp->st_size; len > 0; len -= wlen) { \ if (mode == RAND_BYTES) { \ for (i = 0; i < sizeof(buf); \ i+= sizeof(u_int32_t)) \ *(int *)(buf + i) = arc4random(); \ } \ wlen = len < (off_t)sizeof(buf) ? (size_t)len : sizeof(buf); \ if ((size_t)write(fd, buf, wlen) != wlen) \ goto err; \ } \ sync(); /* another poke at hidden caches */ \ } while (0) #define READ_PASS(byte) do { \ off_t len; \ size_t rlen; \ char pattern[8 * 1024]; \ char buf[8 * 1024]; \ \ if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET)) \ goto err; \ \ memset(pattern, byte, sizeof(pattern)); \ for(len = sbp->st_size; len > 0; len -= rlen) { \ rlen = len < (off_t)sizeof(buf) ? (size_t)len : sizeof(buf); \ if((size_t)read(fd, buf, rlen) != rlen) \ goto err; \ if(memcmp(buf, pattern, rlen)) \ goto err; \ } \ sync(); /* another poke at hidden caches */ \ } while (0) /* * DSS sanitization matrix "clear" for magnetic disks: * option 'c' "Overwrite all addressable locations with a single * character." */ randint = arc4random(); randchar = *(char *)&randint; WRITE_PASS(THIS_BYTE, randchar); /* * DSS sanitization matrix "sanitize" for magnetic disks: * option 'd', sub 2 "Overwrite all addressable locations with a * character, then its complement. Verify "complement" character * was written successfully to all addressable locations, then * overwrite all addressable locations with random characters; or * verify third overwrite of random characters." The rest of the * text in d-sub-2 specifies requirements for overwriting spared * sectors; we cannot conform to it when erasing only a file, thus * we do not conform to the standard. */ /* 1. "a character" */ WRITE_PASS(THIS_BYTE, 0xff); /* 2. "its complement" */ WRITE_PASS(THIS_BYTE, 0x00); /* 3. "Verify 'complement' character" */ READ_PASS(0x00); /* 4. "overwrite all addressable locations with random characters" */ WRITE_PASS(RAND_BYTES, 0x00); /* * As the file might be huge, and we note that this revision of * the matrix says "random characters", not "a random character" * as the original did, we do not verify the random-character * write; the "or" in the standard allows this. */ if (close(fd) == -1) { fd = -1; goto err; } return 0; err: eval = 1; warn("%s", file); if (fd != -1) close(fd); return 1; } static int check(char *path, char *name, struct stat *sp, const char *dowhat) { int ch, first; char modep[15]; /* Check -i first. */ if (iflag) (void)fprintf(stderr, "%s '%s'? ", dowhat, path); else { /* * If it's not a symbolic link and it's unwritable and we're * talking to a terminal, ask. Symbolic links are excluded * because their permissions are meaningless. Check stdin_ok * first because we may not have stat'ed the file. */ if (!stdin_ok || S_ISLNK(sp->st_mode) || !(access(name, W_OK) && (errno != ETXTBSY))) return (1); strmode(sp->st_mode, modep); if (Pflag) { warnx( "%s: -P was specified but file could not" " be overwritten", path); return 0; } (void)fprintf(stderr, "override %s%s%s:%s for '%s'? ", modep + 1, modep[9] == ' ' ? "" : " ", user_from_uid(sp->st_uid, 0), group_from_gid(sp->st_gid, 0), path); } (void)fflush(stderr); first = ch = getchar(); while (ch != '\n' && ch != EOF) ch = getchar(); return (first == 'y' || first == 'Y'); } /* * POSIX.2 requires that if "." or ".." are specified as the basename * portion of an operand, a diagnostic message be written to standard * error and nothing more be done with such operands. * * Since POSIX.2 defines basename as the final portion of a path after * trailing slashes have been removed, we'll remove them here. */ #define ISDOT(a) ((a)[0] == '.' && (!(a)[1] || ((a)[1] == '.' && !(a)[2]))) static void checkdot(char **argv) { char *p, **save, **t; int complained; complained = 0; for (t = argv; *t;) { /* strip trailing slashes */ p = strrchr(*t, '\0'); while (--p > *t && *p == '/') *p = '\0'; /* extract basename */ if ((p = strrchr(*t, '/')) != NULL) ++p; else p = *t; if (ISDOT(p)) { if (!complained++) warnx("\".\" and \"..\" may not be removed"); eval = 1; for (save = t; (t[0] = t[1]) != NULL; ++t) continue; t = save; } else ++t; } } static void usage(void) { (void)fprintf(stderr, "usage: %s [-f|-i] [-dPRrvWx] file ...\n", getprogname()); exit(1); /* NOTREACHED */ } static void progress(int sig __unused) { pinfo++; }
