3 // Copyright (C) 2003 Enrico Scholz <enrico.scholz@informatik.tu-chemnitz.de>
5 // This program is free software; you can redistribute it and/or modify
6 // it under the terms of the GNU General Public License as published by
7 // the Free Software Foundation; version 2 of the License.
9 // This program is distributed in the hope that it will be useful,
10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 // GNU General Public License for more details.
14 // You should have received a copy of the GNU General Public License
15 // along with this program; if not, write to the Free Software
16 // Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19 // secure-mount <general mount(8) options> [--chroot]
20 // [--mtab <mtabfile>] [--fstab <fstabfile>]
22 // Executes mount-operations under the current directory: it assumes sources
23 // in the current root-dir while destinations are expected in the chroot
32 #include "pathconfig.h"
34 #include <lib/internal.h>
45 #include <sys/mount.h>
47 #include <sys/types.h>
56 #define ENSC_WRAPPERS_FCNTL 1
57 #define ENSC_WRAPPERS_UNISTD 1
60 #define MNTPOINT "/etc"
62 typedef enum { rfsYES, rfsNO, rfsONLY } RootFsOption;
86 #define OPTION_BIND 1024
87 #define OPTION_MOVE 1025
88 #define OPTION_MTAB 1026
89 #define OPTION_FSTAB 1027
90 #define OPTION_CHROOT 1028
91 #define OPTION_SECURE 1029
92 #define OPTION_RBIND 1030
93 #define OPTION_ROOTFS 1031
95 #define XFLAG_NOAUTO 0x01
97 static struct option const
99 { "help", no_argument, 0, 'h' },
100 { "version", no_argument, 0, 'v' },
101 { "bind", no_argument, 0, OPTION_BIND },
102 { "move", no_argument, 0, OPTION_MOVE },
103 { "mtab", required_argument, 0, OPTION_MTAB },
104 { "fstab", required_argument, 0, OPTION_FSTAB },
105 { "rootfs", required_argument, 0, OPTION_ROOTFS },
106 { "chroot", no_argument, 0, OPTION_CHROOT },
107 { "secure", no_argument, 0, OPTION_SECURE },
108 { "rbind", no_argument, 0, OPTION_RBIND },
113 # define MS_REC 0x4000
116 static struct FstabOption {
117 char const * const opt;
118 unsigned long const flag;
119 unsigned long const mask;
120 unsigned long const xflag;
122 } const FSTAB_OPTIONS[] = {
123 { "defaults", 0, (MS_RDONLY|MS_NOSUID|MS_NODEV|MS_NOEXEC|
124 MS_SYNCHRONOUS), 0, false },
125 { "rbind", MS_BIND|MS_REC, MS_BIND|MS_REC, 0, false },
126 { "bind", MS_BIND, MS_BIND, 0, false },
127 { "move", MS_MOVE, MS_MOVE, 0, false },
128 { "async", 0, MS_SYNCHRONOUS, 0, false },
129 { "sync", MS_SYNCHRONOUS, MS_SYNCHRONOUS, 0, false },
130 { "atime", 0, MS_NOATIME, 0, false },
131 { "noatime", MS_NOATIME, MS_NOATIME, 0, false },
132 { "dev", 0, MS_NODEV, 0, false },
133 { "nodev", MS_NODEV, MS_NODEV, 0, false },
134 { "exec", 0, MS_NOEXEC, 0, false },
135 { "noexec", MS_NOEXEC, MS_NOEXEC, 0, false },
136 { "suid", 0, MS_NOSUID, 0, false },
137 { "nosuid", MS_NOSUID, MS_NOSUID, 0, false },
138 { "ro", MS_RDONLY, MS_RDONLY, 0, false },
139 { "rw", 0, MS_RDONLY, 0, false },
141 { "remount", MS_REMOUNT, MS_REMOUNT, 0, false },
142 { "users", MS_NOEXEC|MS_NOSUID|MS_NODEV,
143 MS_NOEXEC|MS_NOSUID|MS_NODEV, 0, false },
144 { "mandlock", MS_MANDLOCK, MS_MANDLOCK, 0, false },
145 { "nodiratime", MS_NODIRATIME, MS_NODIRATIME, 0, false },
147 { "dirsync", MS_DIRSYNC, MS_DIRSYNC, 0, false },
149 { "_netdev", 0, 0, 0, false },
150 { "auto", 0, 0, 0, false },
151 { "noauto", 0, 0, XFLAG_NOAUTO, false },
152 { "user", 0, 0, 0, false },
153 { "nouser", 0, 0, 0, false },
156 int wrapper_exit_code = 1;
159 showHelp(int fd, char const *cmd, int res)
161 VSERVER_DECLARE_CMD(cmd);
163 WRITE_MSG(fd, "Usage: ");
166 " [--help] [--version] [--bind] [--move] [--rbind] [-t <type>] [--chroot]\n"
167 " [--mtab <filename>] [--fstab <filename>] [--rootfs yes|no|only]\n"
168 " [-n] -a|([-o <options>] [--] <src> <dst>)\n\n"
169 "Executes mount-operations under the current directory: it assumes sources in\n"
170 "the current root-dir while destinations are expected in the chroot environment.\n\n"
171 "For non-trivial mount-operations it uses the external 'mount' program which\n"
172 "can be overridden by the $MOUNT environment variable.\n\n"
174 " --bind|move|rbind ... set the correspond flags; with this options\n"
175 " the mount will be executed internally without\n"
176 " calling an external mount program.\n"
177 " -t <type> ... assume the given filesystem type\n"
178 " -o <options> ... set additional options; see mount(2) for details\n"
179 " -n ... do not update the mtab-file\n"
180 " --mtab <filename> ... use <filename> as an alternative mtab file\n"
181 " [default: /etc/mtab]\n"
182 " --chroot ... chroot into the current directory before\n"
183 " mounting the filesystem\n"
184 " --fstab <filename> ... use <filename> as an alternative fstab file;\n"
185 " this option has an effect only with the '-a'\n"
186 " option [default: /etc/fstab]\n"
187 " --rootfs yes|no|only ... specifies how to handle an entry for a rootfs\n"
188 " ('/') when processing an fstab file. 'yes' will\n"
189 " mount it among the other entries, 'only' will\n"
190 " mount only the rootfs entry, and 'no' will ignore\n"
191 " it and mount only the other entries [default: yes]\n"
192 " -a ... mount everything listed in the fstab-file\n\n"
193 " <src> ... the source-filesystem; this path is absolute\n"
194 " to the current root-filesystem. Only valid\n"
195 " without the '-a' option.\n"
196 " <dst> ... the destination mount-point; when used with\n"
197 " '--chroot', this path is relative to the current\n"
198 " directory. Only valid without the '-a' option\n\n"
199 "Please report bugs to " PACKAGE_BUGREPORT "\n");
208 "secure-mount " VERSION " -- secure mounting of directories\n"
209 "This program is part of " PACKAGE_STRING "\n\n"
210 "Copyright (C) 2003 Enrico Scholz\n"
211 VERSION_COPYRIGHT_DISCLAIMER);
216 isSameObject(struct stat const *lhs,
217 struct stat const *rhs)
219 return (lhs->st_dev==rhs->st_dev &&
220 lhs->st_ino==rhs->st_ino);
226 if (fchdir(fd)==-1 || chroot(".")==-1) return -1;
231 writeX(int fd, void const *buf, size_t len)
233 if ((size_t)(write(fd, buf, len))!=len) return -1;
238 writeStrX(int fd, char const *str)
240 return writeX(fd, str, strlen(str));
243 static inline char const *
244 getType(struct MountInfo const *mnt)
246 if (mnt->type==0) return "none";
247 else if (strncmp(mnt->type, "ext", 3)==0) return "ufs";
248 else return mnt->type;
252 restoreRoot(struct Options const *opt)
254 if (opt->do_chroot!=0 && fchroot(opt->cur_rootdir_fd)==-1) {
255 perror("secure-mount: fchdir(\"/\")");
256 WRITE_MSG(2, "Failed to restore root-directory; aborting\n");
262 updateMtab(struct MountInfo const *mnt, struct Options const *opt)
266 assert(opt->mtab!=0);
268 if (opt->do_chroot && fchroot(opt->cur_dir_fd)==-1) {
269 perror("secure-mount: fchroot(\".\")");
273 fd=open(opt->mtab, O_CREAT|O_APPEND|O_WRONLY, 0644);
276 perror("secure-mount: open(<mtab>)");
280 if (flock(fd, LOCK_EX)==-1) {
281 perror("secure-mount: flock()");
285 if (writeStrX(fd, mnt->src)==-1 ||
286 writeStrX(fd, " ")==-1 ||
287 writeStrX(fd, mnt->dst)==-1 ||
288 writeStrX(fd, " ")==-1 ||
289 writeStrX(fd, getType(mnt))==-1 ||
290 writeStrX(fd, " ")==-1 ||
291 writeStrX(fd, mnt->data ? mnt->data : "defaults")==-1 ||
292 writeStrX(fd, " 0 0\n")==-1) {
293 perror("secure-mount: write()");
306 callExternalMount(struct MountInfo const *mnt)
308 char const * argv[10];
312 char const * mount_prog = getenv("MOUNT");
314 if (mount_prog==0) mount_prog = MOUNT_PROG;
316 argv[idx++] = mount_prog;
318 if (mnt->flag & MS_BIND) argv[idx++] = "--bind";
319 else if (mnt->flag & MS_MOVE) argv[idx++] = "--move";
322 if (mnt->data && *mnt->data &&
323 strcmp(mnt->data, "defaults")!=0) {
324 if (mnt->mask & MS_NODEV)
325 argv[idx++] = mnt->data;
327 char * tmp = alloca(strlen(mnt->data) + sizeof("nodev,"));
328 strcpy(tmp, "nodev,");
329 strcat(tmp, mnt->data);
334 argv[idx++] = "nodev";
338 argv[idx++] = mnt->type;
341 argv[idx++] = mnt->src;
347 perror("secure-mount: fork()");
352 execv(mount_prog, const_cast(char **)(argv));
353 PERROR_Q("secure-mount: execv", mount_prog);
357 if (wait4(pid, &status, 0, 0)==-1) {
358 perror("secure-mount: wait4()");
362 return (WIFEXITED(status)) && (WEXITSTATUS(status)==0);
366 secureChdir(char const *dir, struct Options const *opt)
371 if (opt->do_chroot!=0 && fchroot(opt->cur_dir_fd)==-1) {
372 perror("secure-mount: fchroot(\".\")");
376 if (chdir(dir)==-1) {
377 PERROR_Q("secure-mount: chdir", dir);
381 dir_fd = open(".", O_RDONLY|O_DIRECTORY);
383 perror("secure-mount: open(\".\")");
388 if (fchdir(dir_fd)==-1)
389 PERROR_Q("secure-mount: fchdir", dir);
402 canHandleInternal(struct MountInfo const *mnt)
404 static char const * FS[] = {
405 "tmpfs", "sysfs", "proc", "sockfs", "pipefs", "futexfs",
406 "inotifyfs", "devpts", "ext3", "ext2", "ramfs",
407 "hugetlbfs", "usbfs", "binfmt_misc",
412 if (!mnt) return false;
413 else if ((mnt->flag & (MS_BIND|MS_MOVE))) return true;
414 else if (mnt->type==0) return false;
416 for (i=FS+0; *i!=0; ++i)
417 if (strcmp(mnt->type, *i)==0) return true;
423 mountSingle(struct MountInfo const *mnt, struct Options const *opt)
427 if (!secureChdir(mnt->dst, opt))
430 if (canHandleInternal(mnt)) {
431 unsigned long flag = mnt->flag;
432 if (!(flag & MS_NODEV)) flag |= MS_NODEV;
434 if (mount(mnt->src, ".",
435 mnt->type ? mnt->type : "",
436 flag, mnt->data)==-1) {
437 perror("secure-mount: mount()");
441 else if (!callExternalMount(mnt))
444 if (!opt->ignore_mtab &&
445 updateMtab(mnt, opt)==-1) {
446 WRITE_MSG(2, "Failed to update mtab-file\n");
453 static struct FstabOption const *
454 searchOption(char const *opt, size_t len)
456 struct FstabOption const * i;
457 for (i=FSTAB_OPTIONS+0; i<FSTAB_OPTIONS+DIM_OF(FSTAB_OPTIONS); ++i)
458 if (strncmp(i->opt, opt, len)==0) return i;
464 transformOptionList(struct MountInfo *info, size_t UNUSED *col)
466 char const * ptr = info->data;
469 char const * pos = strchr(ptr, ',');
470 struct FstabOption const * opt;
472 if (pos==0) pos = ptr+strlen(ptr);
473 opt = searchOption(ptr, pos-ptr);
476 info->flag &= ~opt->mask;
477 info->flag |= opt->flag;
478 info->mask |= opt->mask;
479 info->xflag |= opt->xflag;
487 } while (*ptr!='\0');
492 #define MOVE_TO_NEXT_FIELD(PTR,ALLOW_EOL) \
493 while (!isspace(*PTR) && *PTR!='\0') ++PTR; \
494 if (col) *col = buf-start_buf+1; \
495 if (!(ALLOW_EOL) && *PTR=='\0') return prFAIL; \
497 while (isspace(*PTR)) ++PTR
499 static enum {prDOIT, prFAIL, prIGNORE}
500 parseFstabLine(struct MountInfo *info, char *buf, size_t *col)
502 char const * const start_buf = buf;
505 while (isspace(*buf)) ++buf;
506 if (*buf=='#' || *buf=='\0') return prIGNORE;
509 MOVE_TO_NEXT_FIELD(buf, false);
511 MOVE_TO_NEXT_FIELD(buf, false);
513 MOVE_TO_NEXT_FIELD(buf, false);
514 err_col = buf-start_buf+1;
516 MOVE_TO_NEXT_FIELD(buf, true);
518 info->flag = MS_NODEV;
522 if (strcmp(info->type, "swap") ==0) return prIGNORE;
523 else if (strcmp(info->type, "none") ==0) info->type = 0;
524 else if (strcmp(info->type, "devpts")==0) {
525 info->mask |= MS_NODEV;
526 info->flag &= ~MS_NODEV;
529 if (col) *col = err_col;
530 if (!transformOptionList(info,col)) return prFAIL;
531 if (info->xflag & XFLAG_NOAUTO) return prIGNORE;
536 #undef MOVE_TO_NEXT_FIELD
539 showFstabPosition(int fd, char const *fname, size_t line_nr, size_t col_nr)
541 char buf[3*sizeof(line_nr)*2 + 4];
542 size_t len = utilvserver_fmt_uint(buf+1, line_nr)+1;
546 len += utilvserver_fmt_uint(buf+len, col_nr);
547 WRITE_STR(fd, fname);
548 Vwrite(fd, buf, len);
553 mountFstab(struct Options const *opt)
559 assert(opt->fstab!=0);
560 fd = open(opt->fstab, O_RDONLY);
562 perror("secure-mount: open(<fstab>)");
566 len = lseek(fd, 0, SEEK_END);
568 lseek(fd, 0, SEEK_SET)==-1) {
569 perror("secure-mount: lseek(<fstab>)");
576 size_t line_nr=0, col_nr;
578 if (read(fd, buf, len+1)!=len) {
579 perror("secure-mount: read()");
582 buf[len] = '#'; // workaround for broken dietlibc strtok_r()
587 while ((ptr=strsep(&ptrptr, "\n")) != 0) {
588 struct MountInfo mnt;
591 switch (parseFstabLine(&mnt, ptr, &col_nr)) {
593 showFstabPosition(2, opt->fstab, line_nr, col_nr);
594 WRITE_MSG(2, ": syntax error\n");
597 case prIGNORE : break;
599 bool is_rootfs = (strcmp(mnt.dst, "/")==0);
601 if (( is_rootfs && opt->rootfs==rfsNO) ||
602 (!is_rootfs && opt->rootfs==rfsONLY)) { /* ignore the entry */ }
603 else if (!mountSingle(&mnt, opt)) {
604 showFstabPosition(2, opt->fstab, line_nr, 1);
605 WRITE_MSG(2, ": failed to mount fstab-entry\n");
622 initFDs(struct Options *opt)
624 opt->cur_dir_fd = Eopen(".", O_RDONLY|O_DIRECTORY, 0);
625 opt->cur_rootdir_fd = Eopen("/", O_RDONLY|O_DIRECTORY, 0);
627 Efcntl(opt->cur_dir_fd, F_SETFD, FD_CLOEXEC);
628 Efcntl(opt->cur_rootdir_fd, F_SETFD, FD_CLOEXEC);
632 parseRootFS(char const *str)
634 if (strcasecmp(str, "yes")==0) return rfsYES;
635 else if (strcasecmp(str, "no")==0) return rfsNO;
636 else if (strcasecmp(str, "only")==0) return rfsONLY;
638 WRITE_MSG(2, "secure-mount: invalid option for '--rootfs': '");
641 exit(wrapper_exit_code);
645 int main(int argc, char *argv[])
647 struct MountInfo mnt = {
656 struct Options opt = {
658 .fstab = "/etc/fstab",
660 .ignore_mtab = false,
663 .cur_rootdir_fd = -1,
668 int c = getopt_long(argc, argv, "ht:nao:", CMDLINE_OPTIONS, 0);
672 case 'h' : showHelp(1, argv[0], 0);
673 case 'v' : showVersion();
674 case 't' : mnt.type = optarg; break;
675 case 'n' : opt.ignore_mtab = true; break;
676 case 'a' : opt.mount_all = true; break;
677 case 'o' : mnt.data = optarg; break;
678 case OPTION_RBIND : mnt.flag |= MS_REC; /*@fallthrough@*/
679 case OPTION_BIND : mnt.flag |= MS_BIND; break;
680 case OPTION_MOVE : mnt.flag |= MS_MOVE; break;
681 case OPTION_MTAB : opt.mtab = optarg; break;
682 case OPTION_FSTAB : opt.fstab = optarg; break;
683 case OPTION_CHROOT: opt.do_chroot = true; break;
684 case OPTION_ROOTFS: opt.rootfs = parseRootFS(optarg); break;
686 WRITE_MSG(2, "secure-mount: The '--secure' option is deprecated...\n");
689 WRITE_MSG(2, "Try '");
690 WRITE_STR(2, argv[0]);
691 WRITE_MSG(2, " --help\" for more information.\n");
698 if (opt.mount_all && optind<argc) {
699 WRITE_MSG(2, "Can not specify <src> and '-a' at the same time\n");
704 signal(SIGCHLD, SIG_DFL);
707 if (!mountFstab(&opt)) return EXIT_FAILURE;
708 else return EXIT_SUCCESS;
711 if (optind+2!=argc) {
712 WRITE_MSG(2, "Invalid <src> <dst> pair specified\n");
717 mnt.data = strdup(mnt.data);
718 if (!transformOptionList(&mnt, 0)) {
719 WRITE_MSG(2, "Invalid options specified\n");
724 mnt.src = argv[optind++];
725 mnt.dst = argv[optind++];
727 if (!mountSingle(&mnt, &opt)) return EXIT_FAILURE;