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>
57 #define ENSC_WRAPPERS_FCNTL 1
58 #define ENSC_WRAPPERS_UNISTD 1
61 #define MNTPOINT "/etc"
63 typedef enum { rfsYES, rfsNO, rfsONLY } RootFsOption;
87 #define OPTION_BIND 1024
88 #define OPTION_MOVE 1025
89 #define OPTION_MTAB 1026
90 #define OPTION_FSTAB 1027
91 #define OPTION_CHROOT 1028
92 #define OPTION_SECURE 1029
93 #define OPTION_RBIND 1030
94 #define OPTION_ROOTFS 1031
96 #define XFLAG_NOAUTO 0x01
98 static struct option const
100 { "help", no_argument, 0, 'h' },
101 { "version", no_argument, 0, 'v' },
102 { "bind", no_argument, 0, OPTION_BIND },
103 { "move", no_argument, 0, OPTION_MOVE },
104 { "mtab", required_argument, 0, OPTION_MTAB },
105 { "fstab", required_argument, 0, OPTION_FSTAB },
106 { "rootfs", required_argument, 0, OPTION_ROOTFS },
107 { "chroot", no_argument, 0, OPTION_CHROOT },
108 { "secure", no_argument, 0, OPTION_SECURE },
109 { "rbind", no_argument, 0, OPTION_RBIND },
114 # define MS_REC 0x4000
117 static struct FstabOption {
118 char const * const opt;
119 unsigned long const flag;
120 unsigned long const mask;
121 unsigned long const xflag;
123 } const FSTAB_OPTIONS[] = {
124 { "defaults", 0, (MS_RDONLY|MS_NOSUID|MS_NODEV|MS_NOEXEC|
125 MS_SYNCHRONOUS), 0, false },
126 { "rbind", MS_BIND|MS_REC, MS_BIND|MS_REC, 0, false },
127 { "bind", MS_BIND, MS_BIND, 0, false },
128 { "move", MS_MOVE, MS_MOVE, 0, false },
129 { "async", 0, MS_SYNCHRONOUS, 0, false },
130 { "sync", MS_SYNCHRONOUS, MS_SYNCHRONOUS, 0, false },
131 { "atime", 0, MS_NOATIME, 0, false },
132 { "noatime", MS_NOATIME, MS_NOATIME, 0, false },
133 { "dev", 0, MS_NODEV, 0, false },
134 { "nodev", MS_NODEV, MS_NODEV, 0, false },
135 { "exec", 0, MS_NOEXEC, 0, false },
136 { "noexec", MS_NOEXEC, MS_NOEXEC, 0, false },
137 { "suid", 0, MS_NOSUID, 0, false },
138 { "nosuid", MS_NOSUID, MS_NOSUID, 0, false },
139 { "ro", MS_RDONLY, MS_RDONLY, 0, false },
140 { "rw", 0, MS_RDONLY, 0, false },
142 { "remount", MS_REMOUNT, MS_REMOUNT, 0, false },
143 { "users", MS_NOEXEC|MS_NOSUID|MS_NODEV,
144 MS_NOEXEC|MS_NOSUID|MS_NODEV, 0, false },
145 { "mandlock", MS_MANDLOCK, MS_MANDLOCK, 0, false },
146 { "nodiratime", MS_NODIRATIME, MS_NODIRATIME, 0, false },
148 { "dirsync", MS_DIRSYNC, MS_DIRSYNC, 0, false },
150 { "_netdev", 0, 0, 0, false },
151 { "auto", 0, 0, 0, false },
152 { "noauto", 0, 0, XFLAG_NOAUTO, false },
153 { "user", 0, 0, 0, false },
154 { "nouser", 0, 0, 0, false },
157 int wrapper_exit_code = 1;
160 showHelp(int fd, char const *cmd, int res)
162 VSERVER_DECLARE_CMD(cmd);
164 WRITE_MSG(fd, "Usage: ");
167 " [--help] [--version] [--bind] [--move] [--rbind] [-t <type>] [--chroot]\n"
168 " [--mtab <filename>] [--fstab <filename>] [--rootfs yes|no|only]\n"
169 " [-n] -a|([-o <options>] [--] <src> <dst>)\n\n"
170 "Executes mount-operations under the current directory: it assumes sources in\n"
171 "the current root-dir while destinations are expected in the chroot environment.\n\n"
172 "For non-trivial mount-operations it uses the external 'mount' program which\n"
173 "can be overridden by the $MOUNT environment variable.\n\n"
175 " --bind|move|rbind ... set the correspond flags; with this options\n"
176 " the mount will be executed internally without\n"
177 " calling an external mount program.\n"
178 " -t <type> ... assume the given filesystem type\n"
179 " -o <options> ... set additional options; see mount(2) for details\n"
180 " -n ... do not update the mtab-file\n"
181 " --mtab <filename> ... use <filename> as an alternative mtab file\n"
182 " [default: /etc/mtab]\n"
183 " --chroot ... chroot into the current directory before\n"
184 " mounting the filesystem\n"
185 " --fstab <filename> ... use <filename> as an alternative fstab file;\n"
186 " this option has an effect only with the '-a'\n"
187 " option [default: /etc/fstab]\n"
188 " --rootfs yes|no|only ... specifies how to handle an entry for a rootfs\n"
189 " ('/') when processing an fstab file. 'yes' will\n"
190 " mount it among the other entries, 'only' will\n"
191 " mount only the rootfs entry, and 'no' will ignore\n"
192 " it and mount only the other entries [default: yes]\n"
193 " -a ... mount everything listed in the fstab-file\n\n"
194 " <src> ... the source-filesystem; this path is absolute\n"
195 " to the current root-filesystem. Only valid\n"
196 " without the '-a' option.\n"
197 " <dst> ... the destination mount-point; when used with\n"
198 " '--chroot', this path is relative to the current\n"
199 " directory. Only valid without the '-a' option\n\n"
200 "Please report bugs to " PACKAGE_BUGREPORT "\n");
209 "secure-mount " VERSION " -- secure mounting of directories\n"
210 "This program is part of " PACKAGE_STRING "\n\n"
211 "Copyright (C) 2003 Enrico Scholz\n"
212 VERSION_COPYRIGHT_DISCLAIMER);
217 isSameObject(struct stat const *lhs,
218 struct stat const *rhs)
220 return (lhs->st_dev==rhs->st_dev &&
221 lhs->st_ino==rhs->st_ino);
227 if (fchdir(fd)==-1 || chroot(".")==-1) return -1;
232 writeX(int fd, void const *buf, size_t len)
234 if ((size_t)(write(fd, buf, len))!=len) return -1;
239 writeStrX(int fd, char const *str)
241 return writeX(fd, str, strlen(str));
244 static inline char const *
245 getType(struct MountInfo const *mnt)
247 if (mnt->type==0) return "none";
248 else if (strncmp(mnt->type, "ext", 3)==0) return "ufs";
249 else return mnt->type;
253 restoreRoot(struct Options const *opt)
255 if (opt->do_chroot!=0 && fchroot(opt->cur_rootdir_fd)==-1) {
256 perror("secure-mount: fchdir(\"/\")");
257 WRITE_MSG(2, "Failed to restore root-directory; aborting\n");
263 updateMtab(struct MountInfo const *mnt, struct Options const *opt)
267 assert(opt->mtab!=0);
269 if (opt->do_chroot && fchroot(opt->cur_dir_fd)==-1) {
270 perror("secure-mount: fchroot(\".\")");
274 fd=open(opt->mtab, O_CREAT|O_APPEND|O_WRONLY, 0644);
277 perror("secure-mount: open(<mtab>)");
281 if (flock(fd, LOCK_EX)==-1) {
282 perror("secure-mount: flock()");
286 if (writeStrX(fd, mnt->src)==-1 ||
287 writeStrX(fd, " ")==-1 ||
288 writeStrX(fd, mnt->dst)==-1 ||
289 writeStrX(fd, " ")==-1 ||
290 writeStrX(fd, getType(mnt))==-1 ||
291 writeStrX(fd, " ")==-1 ||
292 writeStrX(fd, mnt->data ? mnt->data : "defaults")==-1 ||
293 writeStrX(fd, " 0 0\n")==-1) {
294 perror("secure-mount: write()");
307 callExternalMount(struct MountInfo const *mnt)
309 char const * argv[10];
313 char const * mount_prog = getenv("MOUNT");
315 if (mount_prog==0) mount_prog = MOUNT_PROG;
317 argv[idx++] = mount_prog;
319 if (mnt->flag & MS_BIND) argv[idx++] = "--bind";
320 else if (mnt->flag & MS_MOVE) argv[idx++] = "--move";
323 if (mnt->data && *mnt->data &&
324 strcmp(mnt->data, "defaults")!=0) {
325 if (mnt->mask & MS_NODEV)
326 argv[idx++] = mnt->data;
328 char * tmp = alloca(strlen(mnt->data) + sizeof("nodev,"));
329 strcpy(tmp, "nodev,");
330 strcat(tmp, mnt->data);
335 argv[idx++] = "nodev";
339 argv[idx++] = mnt->type;
342 argv[idx++] = mnt->src;
348 perror("secure-mount: fork()");
353 execv(mount_prog, const_cast(char **)(argv));
354 PERROR_Q("secure-mount: execv", mount_prog);
358 if (wait4(pid, &status, 0, 0)==-1) {
359 perror("secure-mount: wait4()");
363 return (WIFEXITED(status)) && (WEXITSTATUS(status)==0);
367 secureChdir(char const *dir, struct Options const *opt)
372 if (opt->do_chroot!=0 && fchroot(opt->cur_dir_fd)==-1) {
373 perror("secure-mount: fchroot(\".\")");
377 if (chdir(dir)==-1) {
378 PERROR_Q("secure-mount: chdir", dir);
382 dir_fd = open(".", O_RDONLY|O_DIRECTORY);
384 perror("secure-mount: open(\".\")");
389 if (fchdir(dir_fd)==-1)
390 PERROR_Q("secure-mount: fchdir", dir);
403 canHandleInternal(struct MountInfo const *mnt)
405 static char const * FS[] = {
406 "tmpfs", "sysfs", "proc", "sockfs", "pipefs", "futexfs",
407 "inotifyfs", "devpts", "ext3", "ext2", "ramfs",
408 "hugetlbfs", "usbfs", "binfmt_misc",
413 if (!mnt) return false;
414 else if ((mnt->flag & (MS_BIND|MS_MOVE))) return true;
415 else if (mnt->type==0) return false;
417 for (i=FS+0; *i!=0; ++i)
418 if (strcmp(mnt->type, *i)==0) return true;
424 mountSingle(struct MountInfo const *mnt, struct Options const *opt)
428 if (!secureChdir(mnt->dst, opt))
431 if (canHandleInternal(mnt)) {
432 if (mount(mnt->src, ".",
433 mnt->type ? mnt->type : "",
434 mnt->flag, mnt->data)==-1) {
435 perror("secure-mount: mount()");
439 else if (!callExternalMount(mnt))
442 if (!opt->ignore_mtab &&
443 updateMtab(mnt, opt)==-1) {
444 WRITE_MSG(2, "Failed to update mtab-file\n");
451 static struct FstabOption const *
452 searchOption(char const *opt, size_t len)
454 struct FstabOption const * i;
455 for (i=FSTAB_OPTIONS+0; i<FSTAB_OPTIONS+DIM_OF(FSTAB_OPTIONS); ++i)
456 if (strncmp(i->opt, opt, len)==0) return i;
462 transformOptionList(struct MountInfo *info, size_t UNUSED *col)
464 char const * ptr = info->data;
465 char * data = malloc(strlen(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;
484 strncpy(dst, ptr, pos-ptr);
494 } while (*ptr!='\0');
500 #define MOVE_TO_NEXT_FIELD(PTR,ALLOW_EOL) \
501 while (!isspace(*PTR) && *PTR!='\0') ++PTR; \
502 if (col) *col = buf-start_buf+1; \
503 if (!(ALLOW_EOL) && *PTR=='\0') return prFAIL; \
505 while (isspace(*PTR)) ++PTR
507 static enum {prDOIT, prFAIL, prIGNORE}
508 parseFstabLine(struct MountInfo *info, char *buf, size_t *col)
510 char const * const start_buf = buf;
513 while (isspace(*buf)) ++buf;
514 if (*buf=='#' || *buf=='\0') return prIGNORE;
517 MOVE_TO_NEXT_FIELD(buf, false);
519 MOVE_TO_NEXT_FIELD(buf, false);
521 MOVE_TO_NEXT_FIELD(buf, false);
522 err_col = buf-start_buf+1;
524 MOVE_TO_NEXT_FIELD(buf, true);
526 info->flag = MS_NODEV;
530 if (strcmp(info->type, "swap") ==0) return prIGNORE;
531 else if (strcmp(info->type, "none") ==0) info->type = 0;
532 else if (strcmp(info->type, "devpts")==0) {
533 info->mask |= MS_NODEV;
534 info->flag &= ~MS_NODEV;
537 if (col) *col = err_col;
538 if (!transformOptionList(info,col)) return prFAIL;
539 if (info->xflag & XFLAG_NOAUTO) return prIGNORE;
544 #undef MOVE_TO_NEXT_FIELD
547 showFstabPosition(int fd, char const *fname, size_t line_nr, size_t col_nr)
549 char buf[3*sizeof(line_nr)*2 + 4];
550 size_t len = utilvserver_fmt_uint(buf+1, line_nr)+1;
554 len += utilvserver_fmt_uint(buf+len, col_nr);
555 WRITE_STR(fd, fname);
556 Vwrite(fd, buf, len);
561 mountFstab(struct Options const *opt)
567 assert(opt->fstab!=0);
568 fd = open(opt->fstab, O_RDONLY);
570 perror("secure-mount: open(<fstab>)");
574 len = lseek(fd, 0, SEEK_END);
576 lseek(fd, 0, SEEK_SET)==-1) {
577 perror("secure-mount: lseek(<fstab>)");
584 size_t line_nr=0, col_nr;
586 if (read(fd, buf, len+1)!=len) {
587 perror("secure-mount: read()");
590 buf[len] = '#'; // workaround for broken dietlibc strtok_r()
595 while ((ptr=strsep(&ptrptr, "\n")) != 0) {
596 struct MountInfo mnt;
599 switch (parseFstabLine(&mnt, ptr, &col_nr)) {
601 showFstabPosition(2, opt->fstab, line_nr, col_nr);
602 WRITE_MSG(2, ": syntax error\n");
605 case prIGNORE : break;
607 bool is_rootfs = (strcmp(mnt.dst, "/")==0);
609 if (( is_rootfs && opt->rootfs==rfsNO) ||
610 (!is_rootfs && opt->rootfs==rfsONLY)) { /* ignore the entry */ }
611 else if (!mountSingle(&mnt, opt)) {
612 showFstabPosition(2, opt->fstab, line_nr, 1);
613 WRITE_MSG(2, ": failed to mount fstab-entry\n");
630 initFDs(struct Options *opt)
632 opt->cur_dir_fd = Eopen(".", O_RDONLY|O_DIRECTORY, 0);
633 opt->cur_rootdir_fd = Eopen("/", O_RDONLY|O_DIRECTORY, 0);
635 Efcntl(opt->cur_dir_fd, F_SETFD, FD_CLOEXEC);
636 Efcntl(opt->cur_rootdir_fd, F_SETFD, FD_CLOEXEC);
640 parseRootFS(char const *str)
642 if (strcasecmp(str, "yes")==0) return rfsYES;
643 else if (strcasecmp(str, "no")==0) return rfsNO;
644 else if (strcasecmp(str, "only")==0) return rfsONLY;
646 WRITE_MSG(2, "secure-mount: invalid option for '--rootfs': '");
649 exit(wrapper_exit_code);
653 int main(int argc, char *argv[])
655 struct MountInfo mnt = {
664 struct Options opt = {
666 .fstab = "/etc/fstab",
668 .ignore_mtab = false,
671 .cur_rootdir_fd = -1,
676 int c = getopt_long(argc, argv, "ht:nao:", CMDLINE_OPTIONS, 0);
680 case 'h' : showHelp(1, argv[0], 0);
681 case 'v' : showVersion();
682 case 't' : mnt.type = optarg; break;
683 case 'n' : opt.ignore_mtab = true; break;
684 case 'a' : opt.mount_all = true; break;
685 case 'o' : mnt.data = optarg; break;
686 case OPTION_RBIND : mnt.flag |= MS_REC; /*@fallthrough@*/
687 case OPTION_BIND : mnt.flag |= MS_BIND; break;
688 case OPTION_MOVE : mnt.flag |= MS_MOVE; break;
689 case OPTION_MTAB : opt.mtab = optarg; break;
690 case OPTION_FSTAB : opt.fstab = optarg; break;
691 case OPTION_CHROOT: opt.do_chroot = true; break;
692 case OPTION_ROOTFS: opt.rootfs = parseRootFS(optarg); break;
694 WRITE_MSG(2, "secure-mount: The '--secure' option is deprecated...\n");
697 WRITE_MSG(2, "Try '");
698 WRITE_STR(2, argv[0]);
699 WRITE_MSG(2, " --help' for more information.\n");
706 if (opt.mount_all && optind<argc) {
707 WRITE_MSG(2, "Can not specify <src> and '-a' at the same time\n");
712 signal(SIGCHLD, SIG_DFL);
715 if (!mountFstab(&opt)) return EXIT_FAILURE;
716 else return EXIT_SUCCESS;
719 if (optind+2!=argc) {
720 WRITE_MSG(2, "Invalid <src> <dst> pair specified\n");
725 mnt.data = strdup(mnt.data);
726 if (!transformOptionList(&mnt, 0)) {
727 WRITE_MSG(2, "Invalid options specified\n");
732 mnt.src = argv[optind++];
733 mnt.dst = argv[optind++];
735 if (!mountSingle(&mnt, &opt)) return EXIT_FAILURE;